In reinforced concrete constructions, reinforcing bar generates more CO₂ per unit weight than other construction materials. In particular, cutting and bending rebar is the main source of rebar waste in the construction industry. Rebar-cutting waste is inevitable during the construction of a reinforced concrete structure since the rebar is not manufactured as designed. Large amounts of waste can be avoided by utilizing optimal cutting patterns and schedules. This research provides a fundamental analysis of the automatic calculation of column rebar length using BIM-based shape codes to minimize cutting waste to near zero. By employing this approach in practice, it is possible to minimize the rate of rebar-cutting waste, reduce costs, shorten construction duration, and reduce CO₂ emissions. In addition, the development of this research will serve as a clue for the development of BIM-based rebar layout automation algorithms.

In this study, an easily recyclable separable glued-laminated timber (GLT)-steel beam was developed, and a structural design method was presented. The GLT and steel were mechanically composited using self-tapping screws. The GLT-steel beam was designed to fail in the compression of GLT. The bending moment and load-carrying capacity of the GLT-steel beam were predicted based on composite beam theory and compared with experimental test data. As a result, the GLT-steel beam exhibited ductile behavior, and compression failure of GLT was observed. The screw connection showed no damage while the steel plate was extended. The load-carrying capacity of GLT after failure was similar to the load resistance predicted by the compressive strength of GLT and the tensile strength of steel. This indicates that the ductile behavior of the GLT-steel beam can be safely designed by the tensile strength (yield) of steel.

Free-form buildings serve as landmarks, and interest and demand are increasing. However, in the case of free-form concrete members, different curved surfaces are required depending on the location where they are used, and the formwork is custom-made and used. Concrete is poured into the manufactured formwork to produce FCP (Free-form Concrete Panel). However, since it is an atypical building that requires precise curvature, compaction cannot be performed after concrete is poured. This leads to the occurrence of bughole, which reduce the strength and aesthetics of concrete. Therefore, in this study, we intend to conduct basic experiments to develop a magnetic compaction device that can be used for FCP. As a result of the experiment, it was confirmed that the bug hole was improved when the magnetic compaction device was applied, and there was no significant difference in compressive strength and flexural strength. This technology can be used in the field of Free-form concrete where it is difficult to perform compaction work, and it is expected to be used as a basic research related to technology for new automatic compaction.

Currently, the Off-Site Construction (OSC) construction method, which emphasizes the minimization of field work, is being emphasized at construction sites due to the lack of construction skilled manpower, extreme weather, and the Severe Disaster Punishment Act. In this study, we developed a stacked PC modular, which is a method of stacking PC modules, and solved the lifting problem by reducing the weight of the unit module, which is emerging as the biggest disadvantage of PC modules, to around 20 tons. For the connection between modules, structural safety was secured through repeated history tests of the wall and slab connection. Walls and slabs satisfied all statutory fire resistance times through fire resistance tests, and residential performance was evaluated to be satisfactory through mock-up demonstration. The developed PC modular has been applied to the construction of commercial houses, detached houses, shopping malls, churches, etc., and has design results for many buildings such as dormitories, detached houses with 4 floors or more, and resorts, so it is expected that an atmosphere of revitalization of construction methods will be created.

In view of the labor-intensive characteristics of the construction industry and the persistent negative image, the problems of continuous aging and manpower shortage in the domestic construction industry are becoming more and more serious, which must be solved for the survival of the domestic construction industry. China has made certain achievements in prefabricated buildings. Through this research, we describe the development process of China's prefabricated buildings in different stages, and analyze the necessary policy promotion and standard support in the development of prefabricated buildings. Analyze and examine the necessary conditions for China's prefabricated building achievements and success factors, and make better proposals for the development of the construction industry in South Korea.

Recently, with the digitalization of the construction industry, free-form building construction technology is developing. However, the technology for manufacturing free-form concrete panels is still insufficient. In this study, the surface error of the FCP according to the thickness of the lower silicon plate, which is a component of the existing lower multi-point press, was analyzed in order to manufacture a precise FCP. As a result of the analysis, it was found that the thinner the thickness, the larger the error value. These results can be used as a basis for existing research and are expected to be used for research on high-quality FCP manufacturing technology.

Corrosion of reinforcement steel is a major cause of deterioration in reinforced concrete (RC) structures. In order to protect these structures from corrosion, corrosion inhibitors are added to the concrete mix. In recent years, zwitterionic compounds have shown promising results as corrosion inhibitors in concrete due to their ability to form a protective layer on the surface of the reinforcement steel. The experimental study involves preparing concrete samples with different concentrations of adding the hybrid corrosion inhibitor at a high concentration of chloride ions. This study aims to determine the chloride threshold value and service life of hybrid corrosion inhibitors in reinforced concrete based on zwitterions. The samples are subjected to accelerated corrosion tests in a chloride environment to determine the threshold value and service life of the corrosion inhibitor. The effect of hybrid inhibitor on mechanical properties is guaranteed in allowable range. The chloride threshold concentration and service life of hybrid inhibitor containing samples perform greater than those of plain RC.

Safety management of steel frame members is a very important part to maintain safety and function. However, precise inspection is not possible for steel frame members due to finishing materials and insulation materials, leading to poor inspection. For steel members, an insulating spray coating method is used for high thermal conductivity. The insulation spray method is not only uneconomical, but also has the disadvantage of spoiling the aesthetics. In addition, VOCs are released from paints used in spraying, so a solution is needed. In this study, heating paint was used to improve the disadvantages of the insulation spray coating method and the high thermal conductivity of steel frame members. In addition to this, in order to reduce VOCs generated from the paint, active clay was added to produce a functional exothermic paint, and then the experiment was conducted. As the amount of activated clay increased, the film thickness increased, and the VOCs emission and thermal conductivity decreased.

As one of the resource recovery projects, this study aims to select natural fibers and synthetic fibers that can be used for concrete mixing among waste fibers and reuse them for the base concrete mixture. Using waste fiber, we seek a solution to the problem of reduced fluidity and hardening time of fiber-reinforced concrete and find the optimal mix of the ground concrete mixed with waste fiber.

In this study, the compressive strength development was analyzed at early ages of concrete specimens admixed with non-sintered hwangto to reduce the CO₂ emissions generated during cement production. The W/B of the specimens was set at 0.41, the percentage of non-sintered hwangto admixture was set at three levels of 15, 30, and 45%, and the compressive strength were measured at 1, 3, 7, and 28 days. The results showed that the compressive strength decreases as the percentage of non-sintered hwangto increases, but the strength development rate increases, and the NHTC41-15 test specimen developed a compressive strength close to NC41 at 28 days.

Test results for a total of four types of complex waterproofing methods were analyzed. In the case of the A method, the stress generated by high-viscosity compounds adhering to the base test body during the behavior of the test body was transferred to the sheet surface layer. In the case of the B method and the C method, the properties of the waterproof sheet consisting of a non-hardened seal based and a non-hardened seal are well reflected and stress absorption in the non-hardened seal layer acts strongly, rapidly reducing stress transfer to the surface of the waterproof sheet. In the case of the D method, slip occurs due to repeated behavior, and the stress on the attachment surface is reduced, and the stress transfer to the surface is greatly reduced. As a result, four types of composite waterproofing methods resulted in changing the stress transfer mechanism caused by behavior on the concrete surface due to the physical properties of the internal constituent material of the waterproof sheet.

This study evaluated the mechanical and electrical properties of low-cement mortar using a large amount of industrial by-products to reduce carbon emissions from the cement industry. As types of industrial by-products, blast furnace slag and fly ash, which are representative materials, were used, and ultra-high fly ash was mixed and evaluated to solve the problem of initial strength loss. In addition, in order to evaluate the electrical properties, 1% of MWCNT was incorporated relative to the powder mass. As experimental items, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age, and the rate of change in electrical resistance was measured on the 28th day of age. As a result of the experiment, the initial strength of the test specimen mixed with blast furnace slag and fly ash was significantly lower than that of 100% cement, and the specimen mixed with blast furnace slag showed strength equal to that of cement at 28 days of age. As an electrical characteristic, the electrical resistance was reduced when the load was loaded, and this reason is judged to be the effect of improving the conductivity as the connection between CNTs is narrowed by the compressive load.

CLC is used as a filling material for many buildings, and according to energy saving design standards, CLC also requires insulation performance. However, it shows lower insulation performance compared to organic insulation, so additional research is needed. Therefore, in this study, the insulation properties of CLC were analyzed by incorporating EPS beads with high insulation performance into CLC. In this experiment, EPS beads and blast furnace slag were replaced, and W/B was fixed at 33%. The EPS Bead mixing ratio was divided into 5 levels: 0, 0.5, 1.0, 1.5, 2.0 (%), and the experimental items were measured for apparent density and thermal conductivity. As a result of the experiment, the apparent density and thermal conductivity tended to decrease as the mixing ratio of EPS beads increased. It is judged that the density decreased due to the low density and the micropores inside, and the thermal conductivity also decreased.

In the domestic industrial sector, greenhouse gases emitted from the cement industry account for about 10%, with most of them generated during the cement clinker calcination process. During the calcination process, 57% of carbon dioxide is emitted from the decarbonation reaction of limestone, 30% from fuel consumption, and 13% from electricity usage. In response to these issues, the cement industry is making efforts to reduce carbon dioxide emissions by developing technologies for raw material substitution and conversion, improving process efficiency by utilizing low-carbon alternative heat sources, developing CO₂ capture and utilization technologies, and recycling waste materials. In addition, due to the limitations in purchasing and storing industrial byproducts generated from industrial facilities, many studies are underway regarding the recycling of construction waste. Therefore, this study analyzes the manufacture of calcium silicate cement (CSC), which can store carbon dioxide as carbonate minerals in industrial facilities, and aims to contribute to the development of environmentally friendly regenerated cement using construction waste.

The purpose of this study was to review ways to increase mechanical performance and apply to actual structures by reinforcing AL perforated sheets, which are industrial by-products generated after capacitor production, with mortar to reinforce the stress of structural members. The AL perforated sheet was reinforced so that it behaves integrally at the position receiving compression, tension, and bending stress. It was confirmed that the stress received by the AL perforated sheet increased according to the number of reinforcements, and as a result, the mechanical properties were improved.

A new shape-stable composite phase change material (PCM) have been produced via an easy and simple vacuum impregnation method. The composite PCM have been derived from almond shell biochar (ASB) as supporting material and capric acid (CA) as phase change material. Cost effective waste almond shells (AS) are renewable, eco-friendly, and rich in pores which enhance the possibility of CA impregnation. Therefore, in this study, three different ratios of CA (1:1, 1:2 and 1:3) have been incorporated in ASB to produce shape-stabilized phase change composites (ASCAs). Different techniques such as scanning electron microscopy (SEM), Fourier transform-infrared spectroscope (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) have been applied to evaluate the characteristics of ASCAs. The attained composite PCMs have exhibited shape stability with high latent heat storage, that makes it suitable for thermal energy storage applications.

In recent decades, climate change has become an issue of global importance. The calcium sulfoaluminate (CSA) cement emits lower CO₂ than the Portland cements while manufacturing. However, ettringite, which is a main hydration product of CSA cement, starts dehydrating at a temperature above 100℃, hence it may limit the CSA cement for high temperature application. Recently, an early carbonation curing of cement-based material has been extensively studied in terms of carbon neutralization. The carbonation curing of CSA cement has a potential to transform the AFt and AFm phases into calcium carbonate, and the transformation of unstable hydrates to stable hydrates can increase the resistance to elevated temperature. This review study summarizes and discusses the carbonation curing effect of CSA cement and the thermal stability of CSA cement exposed to elevated temperatures.

Recently, large and high-rise buildings are increasing, and accordingly, concrete weight reduction is required. Lightweight aggregate concrete can provide economic feasibility and large space, but safety can be reduced due to problems such as low strength and poor durability. Since the development of such low strength of concrete is important in the early construction stage, it is necessary to evaluate the vertical formwork demolding period at the early age. The correlation was analyzed by measuring the compressive strength and ultrasonic pulse velocity. As a result, the ultrasonic pulse rates of normal and lightweight aggregate concrete at the time of 5 MPa expression, which is the time of vertical mold deformation, were 3.07 km/s and 2.77 km/s for W/B 41, and 2.89 km/s and 2.73 km/s for W/B 33.

This study was proceeded to analyze thixotropy of cement paste according to the addition timing of PVA and borax as a basic study of thixotropy of concrete. According to experiment results, the case added borax first and PVA later is that cement paste shows low thixotorpy, and the case added PVA first and borax later is that cement paste shows thixotropy but in certain mix condition fluidity of decrease due to a chemical bond between PVA and borax. The case add PVA and borax simultaneously is that cement paste was expressed thixotropy in all mix condition. Therefore the case add PVA and borax simultaneously is suitable for expressing thixotropy of cement paste.

The corrosion of steel rebar embedded in the coastal areas is corroding once the chloride ions ingress through the pores of the concrete. Therefore, in the present study, a 100 ㎛ thick Al and Zn coating was deposited by an arc thermal spray process onto the steel. The corrosion studies of these deposited coatings were assessed in 3.5 wt.% NaCl contaminated concrete pore (CP) solution with immersion periods. The results show that the Al coating is more corrosion resistance compared to the Zn coating attributed to the formation of gibbsite (γ-Al(OH)₃) whereas Zn coating exhibits Zn(OH)₂ onto the coating surface as passive layer. The Zn(OH)₂ is readily soluble in an alkaline solution. Alternatively, γ-Al(OH)₃ on the Al coating surface is less solubility in the alkaline pH, which further provides barrier protection against corrosion.

In this study, the steel slag was immersed in CO₂ nano-bubble water by Electric arc funace it was accelerated aging was reviewed through XRD analysis. The main minerals of the electric furnace oxidized slag were spinel and gehlenite, and there was no change with the number of CO₂ nano-bubbles. Minerals such as larnite, calcio-olivine, agnetite, calcite, and spinel were distributed in electrically reduced slag, and the content of calcite more than doubled with CO₂ nano-bubble immersion. Therefore, it is judged that the acceleration aging of Electric arc funace reduced slag is effective according to the immersion of CO₂ nano-bubble.

In order to reduce the high absorption ratio of spent coffee grounds, this study examined the compressive strength and absorption ratio of mortar replacing coated spent coffee grounds according to the type of water repellent. In order to examine this, as the water repellent used, a silane-based water repellent (fluorine-based water repellent) and an acrylic-based water repellent, which are film-type water repellents, and a silane/siloxane-based water repellent, which are penetration-type water repellents, were used. The spent coffee grounds were coated with each of three water repellents, and mortar was prepared by mixing cement and fine aggregate. As a result of the experiment, the compressive strength and absorption ratio of the mortar replaced with coated spent coffee grounds coated with the film-type water repellent were superior to the penetration-type water repellent. Therefore, in order to reduce the high absorption ratio of spent coffee grounds, a suitable water repellent is a film-type water repellent. Among them, it is judged that the acrylic type has excellent water repellency and is suitable.

Recently, the importance of improving air quality has been greatly highlighted due to environmental problems such as indoor air pollution, and efforts are being made to improve indoor air quality not only in Korea but also around the world. In this situation, this study aims to study the physical properties of cement boards using pearlite with excellent physical adsorption performance due to micropores in materials, expanded graphite that is widely used as a flame retardant to prevent heat transfer in the event of a fire. The experimental items are bending fracture load and impact resistance. The bending destruction load at the fiber mixing rates 1, 2, 3, and 4 (%) did not meet the standard 140N, but the bending destruction load at 5% was 168.2N, and the impact resistance of the fiber mixing rates 1 and 2 (%) could not be measured due to cracks and damage, and the impact resistance at 3, 4, and 5 (%).

After mixing the pozzolan-based powder and water repellent with porosity into the cement mortar, microanalysis and measurement of the water repellent contact angle confirmed that the NZS specimen using natural zeolite had the highest contact angle. The specific surface area is increased due to the porosity of natural zeolite, so the adhesion of silane-siloxane is relatively better than that of FA, and it is judged to have a uniform distribution inside the mortar.

This study identified the problems of the current technical education for beginner technical personnel engaged in CM companies, and suggested improvement plans for the problems. The item 'difficulty in improving practical practical skills' appeared the highest, and responses to the items 'insufficient educational programs to improve individual competency' and 'education contents do not keep pace with technological development or the trend of the times' As for improvement measures, 'expanding educational programs to strengthen practical skills' was the highest, followed by responses to 'expansion and systematization of online education' and 'diversification and segmentation of educational contents of each educational institution' appeared high.

Asbestos is a durable and heat-resistant building material used in various building materials such as slate, ceiling tex, and spray paint. It has been banned since 2009 after found to be a first-class carcinogen that causes various cancers and asbestos lung disease. Since workers are likely to be exposed to asbestos in the process of dismantling and removal of asbestos-made building materials and facilities, laws and work standards are proposed by the Ministry of Employment and Labor to ensure the safety of asbestos dismantling work. In addition, prior studies on exposure levels and analysis methods have been conducted in this regard mainly for residents. However, the relation between the results of the risk assessment of the process conducted during the asbestos investigation and the work is still ambiguous for the safety of workers. Therefore, this study proposes a process model development methodology that considers work risk based on the results of a survey from asbestos dismantling companies.

The purpose of this study is to derive the cause of the quantity difference and present the considerations when take-off rebar quantity based on BIM model by comparing the quantity of rebar based on BIM model with 2D drawing. This research was limited to take-off the quantity of rebars in the building frame work, and after take-off the quantity of rebars by 3D modeling the 2D drawing of the target building with Revit, the quantity difference was compared with 2D-based software. Therefore, when take-off the quantity of rebars based on the BIM model, instead of take-off the existing 2D-based quantity premium proportion, according to general structural consider development length, lap splice length, covering thickness, reinforcing bars and spacing. In the future, this study is expected to contribute to improving the accuracy of BIM-based frame construction quantity take-off.

The construction industry's lack of experience and expertise makes it difficult for projects to realize the full benefits of implementing modular construction. Such project performance-hindering elements are often labeled as modular challenges. The added requirement for the transportation of the finished volumetric module is one aspect of the 'module transportation logistics,' the under-researched modular challenge that can prevent projects from incurring maximum cost and productivity benefits. The typical module transportation phases include lifting, transporting, and offloading. From conducting a literature review, this paper aims to investigate the equipment commonly adopted to lift and offload the module and validate its economic efficiency by comparing it with the alternative lifting/offloading equipment used in the two case projects. The results showed that hydraulic jacks are an economic alternative to the crane for lifting/offloading the module. The increase in single-module projects with smaller budgets made crane usage economically undesirable, and this study suggested a viable option for a more economical alternative.

As large logistics buildings have high floor heights and long spans, these buildings are designed as PC structures, and large cranes are used to lift PC members. PC erection planning can generally cause errors depending on the field engineer's experience. To solve this problem, a basic analysis method is needed to establish a systematic PC member erection plan. Crane work can be minimized if the trajectory is easily and quickly calculated according to the location of the crane and applied to the site. Therefore, the objective of this study is a basic study of crane trajectory distance calculation for sustainable PC members erection of large logistic building. In this study, a crawler crane commonly used for lifting PC members is limited. The trajectory distance for the PC erection plan was automatically calculated using the algorithm.

Reinforced concrete structures require large amounts of concrete and rebar in the construction stage. Rebar is a major resource for reinforced concrete structures, and generates more CO₂ per unit weight than other materials. To solve this problem, it was confirmed that the cutting waste can be close to zero when the special length of the rebar is calculated in the drawing created after structural design. However, a system for automatically calculating the length of reinforcing bars to efficiently calculate the total amount of reinforcing bars has not been established. Therefore, the objective of this study is a basic study of automatic rebar length estimate algorithm of bearing wall by using BIM-based shape codes built in Revit. The bearing wall rebar can be automatically derived using the developed model. Furthermore, through applying the developed model to the construction field, it will greatly contribute to reducing greenhouse gas emissions by reducing rebar cutting waste.

Since the COVID-19 pandemic, the importance of remote work has been emphasized, and new digital technologies are rapidly being developed. One such digital technology is the metaverse, which combines reality and virtual space to create an expanded digital world. The metaverse can provide online collaborative spaces that visualize and transmit information and data in real-time. When applied to construction sites, this technology is expected to enable more efficient and stable project management. However, research on construction metaverses, both domestically and internationally, is still inadequate. In this study, 16 influential factors for promoting the application of metaverses to the construction industry were identified through the initial stages of the system dynamics technique. These performance factors were classified into four categories: systemrelated factors for metaverse site construction, device-related factors, user-related factors, and construction site-related factors. It is expected that this study will promote research on the activation of Con-Metaverse by developing casual loop diagrams(CLD) to identify the relationship between each performance factor and constructing stock & flow diagrams(SFD) for simulations in future studies.

Wall structure smart modular is a building construction method where modules are manufactured in a factory and assembled on-site. This method is gaining popularity in the construction industry as it reduces construction time and mitigates risks such as material supply and labor costs. Wall structure smart modular is necessary as it provides comfortable temporary classroom space during renovation and remodeling of aging school buildings. The structure and characteristics of each type of temporary classroom modular were compared, and wall structure modular showed superior performance in terms of height and weight competitiveness compared to mixed structures. With these advantages, wall structure modular can ensure economic efficiency and recyclability as a temporary classroom. In the future, we aim to compare and analyze the standards such as inter-floor noise and heat transfer coefficient for wall structure and mixed structures.

This study confirmed the improvement of the Composite Waterproof Method in which the sheet layer is partially attached with perforated film and the joint is FRP-treated.

In accordance with changes in the domestic construction environment, interest in off-site construction methods (factory-manufactured construction methods) including modular construction methods is rapidly increasing. Among various off-site (OSC) construction methods, the front runner is the steel-based box-type modular construction method. Compared to the existing wet construction method, the steel modular construction method is increasing in terms of securing economic feasibility by shortening the construction period and increasing the prefabrication rate. However, due to the recent rise in raw materials and a sharp rise in the exchange rate, the economic feasibility of the wet method is deteriorating compared to the wet method. Therefore, a hybrid between 9-Matrix-based OSC construction methods is considered as a solution, away from the steel-box type combination, and a comparative study of the construction process between each construction method is being conducted. It was analyzed that the PC modular construction method shortened the construction period by 9% compared to the existing steel modular construction method. On the other hand, when comparing the construction period of the Gayang-dong demonstration complex calculated assuming that all modules are applied, it is estimated that there will be a 12% reduction in construction period compared to the steel modular method and a whopping 43% compared to the RC method.

This dissertation investigates the feasibility of accurately calculating the required rebar length using BIM-based shape codes and the potential benefits of such an approach in terms of cost reduction, waste reduction, and environmental improvement. The study aims to explore the possibility of automatically calculating slab rebar length before construction to reduce rebar cutting waste and cost. The results of this study will provide insights into the potential of using shape codes to reduce rebar cutting waste and cost in building frame construction.

With the development of technology, interest in the implementation of free-form buildings is increasing, and research on producing free-form panels is being conducted accordingly. Since free-form buildings are curved and consist of geometric shapes, there are many problems with the production technology of free-form panels that implement them. Due to the inability to reuse molds, the cost of disposal of construction waste and waste of manpower for assembly increase the construction period and construction cost. To improve these limitations, a 3D printed concrete nozzle for FCP production was developed. However, this technology is not quantitatively extruded according to the shape of the panel, and there is a problem that residues are generated. Therefore, an free-form panel extrusion experiment was conducted to analyze the limitations of existing nozzles and to analyze the requirements for the development of new concrete extrusion nozzles. Existing nozzles were unable to be quantitatively extruded, resulting in errors. Due to the weak pressure of the screw and the inability to adjust the internal pressure, detailed extrusion speed control was impossible, and residue generation in the opening and closing device seemed to be the cause. Therefore, a pump capable of quantitative concrete pressure transfer and a pressure control device for easy extrusion of concrete are required. In addition, it is judged that it is necessary to develop an opening and closing device and an extrusion device that do not generate residues. The results of this study are expected to provide information for FCP production and production and to be a basic study of technologies necessary for the production of free-form building panels.

Through the industrial revolution that began in the 18th century, the amount of carbon dioxide in the atmosphere increased rapidly as humans used fossil energy such as coal and oil as fuel for steam engines and factory machines. The amount of carbon dioxide emitted while producing cement, the main material of concrete used in construction, is large enough to account for 5-8% of the world's carbon dioxide emissions. In this study, Non cement-based matrix were used to reduce carbon dioxide emissions from cement production. Red mud is an industrial by-product generated in the manufacturing process of aluminum hydroxide using bauxite, and more than 120 million tons are produced worldwide. In addition, red mud is a porous material that can be physically adsorbed, and causes a photocatalytic reaction of TiO₂ to remove harmful substances such as nitrogen oxide formaldehyde in the air and chemically adsorbs ammonia and hydrogen sulfide. Therefore, this study aims to examine the physical properties of the matrix by mixing red mud, an industrial by-product with good adsorption performance, into the Non cement-based matrix.

In this study, the table flow of fiber reinforced cement composites mixed with CNTs dispersed differently according to the dispersion method was evaluated. The mixture was composed of plain mixture according to the presence or absence of ultrasonic dispersion and PCE-based dispersants A and B of 0.5% and 1.0%, respectively, CNT was mixed with 0.03% of cement weight and fiber was mixed with 1.5% of total volume. As a result of the experiment, NC-A0.5 showed a fluidity similar to that of P without CNT. The fluidity of NC-A0.5 and P-N showed a similar tendency, which is considered to be due to the distribution of evenly dispersed CNT particles without agglomeration between cement particles due to the dispersant. NC-B0.5 showed a similar level of firmness to P-U, but after hitting 250 mm, B Agent seems to have a significant effect on liquidity improvement.Both NC-A1.0 and NC-B1.0 seem to have increased flow due to excessive dispersion.

In this study, comparison of the quality standard of chemical admixtures between Korea and China is conducted. It is classified into three types of water reducing agents: standard, delayed, and accelerated according to the sensitivity and strength improvement of the sensitivity and strength of the agent. However, Chinese standards classify reducing agents only as standard, high efficiency, and high performance, and do not add AE agents into water reducing agent. On the other hand, that of Korea has a classification regulation for reducing agents added with AE agents.

In this study, an approach has been made to understand the effect of encapsulation thickness of the nanoencapsulated PCMs on the phase transition kinetics. Paraffin is encapsulated by silica via single pot polycondensation reaction. Different ratios of silica precursor are chosen to encapsulate paraffin. The obtained encapsulated PCMs are identified as nano sized, as well as with increasing silica precursor, thicker silica encapsulations have been manifested with shrinking core diameter. The synthesized PCMs are characterized using various characterization techniques. Isochronal kinetic studies are done in differential scanning calorimeter (DSC) to understand about their phase transformation behaviors. This study can appreciate the cognition of the large-scale applications of PCMs into the building constructions as well as the fundamental conception on the phase transition kinetics of PCMs can also be amended.

This study aims to mix the base concrete by mixing latex to improve the durability performance to reduce the composite deterioration of the base concrete. Latex fiber has high resistance to freezing and thawing, adhesion, and deicing agent (calcium chloride), and it is used to secure long-term durability to reduce cracking and compound deterioration of concrete. In addition, through experiments, we are trying to find ways to improve the strength of concrete by studying the mixing of the appropriate mixing ratio of latex.

In this study, the correlation between the rheolog y parameter of fresh concrete and the rheology parameter of wet sieving mortar was analyzed for analyzing to possibility predicting the rheology parameter of fresh concrete. Through the experiment, the dynamic yield stress and plastic viscosity of concrete and wet sieving mortar show a direct proportional relationship, and the two data had a correlation. Therefore, it is thought that it is possible to predict the rheology parameter of fresh concrete through the rheology parameter of wet sieving mortar. However, in order to more accurately predict the rheology parameter of fresh concrete, it is need additional relationship analysis by collecting more rheology parameter data of fresh concrete and wet sieving mortar.

Using the limestone powder as material that can alternate the clinker, it seems to get positive effect as filler and enhance workability of cement, but the amount of replacement can affect compressive strength of cement. This study was evaluated the effect of limestone mixed cement fineness and SO₃ content on cement mortar. As a result of measuring the compressive strength, it showed 93% compared to the compressive strength of Plain 28 days at fineness 4,400 and SO₃ 2.6%. It is judged that additional research is necessary to express the strength equivalent to that of Plain.

In this study, in CO₂ sequestration was carried out through pressure carbonation for concrete slurry water to realize carbon neutrality in the cement industry. As a result of the experiment, it was confirmed that as the pressure of CO₂ increased, the pH decreased and the amount of CaCO₃ produced increased. However, despite the CO₂ pressure of 5 bars, the carbonation reaction for 10 minutes alone did not proceed completely.

In this study, mechanical properties of high strength cement composites (HSC) containing recycled glass powder (GP) after heating were investigated. As a result, at 100Mpa, as the heating temperature increased, the compressive strength increased while the elastic modulus decreased . At 140Mpa, after heating at 300℃, the spalling occurred excluding GP0, and it is believed to be due to the high density of HSC.

With the development of cities, the density of the population is continuously increasing as buildings become larger and more high-rise, but since the Haeundae residential complex fire in Busan in 2010, there has been a growing need to meet the fire protection performance of buildings as large-scale fires continue to occur every year. On the other hand, fire doors, which are one of the fire protection performance of buildings, have been judged unqualified in 82% of cases when fire doors constructed on the actual site were inspected after completion. The reason for this is that paper honeycomb and glasswool, which are used as core materials for fire doors, absorb moisture, reducing thermal insulation performance, and sagging due to increased weight, leading to performance degradation due to warping in empty spaces. To overcome these problems, research is underway to apply lightweight aerated concrete, an inorganic material, as a core material. Therefore, in order to select a blowing agent that produces stable bubbles prior to the production of lightweight bubble concrete for application as a fire door inner core, this study examined the physical performance according to the type of blowing agent and dilution concentration, and the following conclusions were drawn. Compared to vegetable bubbles and independent bubbles, synthetic bubbles have 3~8% higher thermal conductivity than independent bubbles, but 3~6% lower slurry density than vegetable bubbles, and 2~13% higher compressive strength, which is thought to be an improvement of synthetic bubbles.

This study measured the thickness and speculation coefficient of the coating for existing buildings and calculated the diffusion coefficient of the coating to predict the depth of carbonation through numerical analysis in order to evaluate the impact of the external finish and local environment. As a result, it was possible to predict the short-term and long-term carbonation depth of reinforced concrete buildings coated with coating film with considerable reliability.

This study aims to investigate and improve the carbon dioxide sequestration capability and the mechanical properties of non-hydraulic low calcium silicate cement especially designed for CO₂ reaction and ordinary Portland cement subjected to the carbonation curing facilitating pH swing method. Nitric acid (HNO₃) was utilized as an liquid for the mixing of cement paste to enhance the initial dissolution of Ca ions from the cements by promoting low pH environment and prevent the direct precipitation of Ca with the anion, owing to the high solubility of Ca(NO₃)₂ in water. The results presented that the higher the concentration of HNO₃, the higher the compressive strength and CO₂ sequestration (until 0.1 M). Ca dissolution caused by the harsh acid attack onto the anhydrous cement particle lead to the higher carbonation reaction degree, forming abundant CaCO₃ crystals after the reaction. However, cement paste mixed with excessively high concentration of HNO₃ presented deterioration due to the too harsh pH environment and abundant NO₃- ions which are known to retard the reaction of cement.

Estimating the construction period at the initial stage of the project and determining whether it is appropriate is very important for the developer's decision-making and the success of the construction company's business. Existing researchers have conducted various studies to calculate the appropriate construction period, but there is no study on the influencing factors and methodology for the construction period of beam-column PC apartment building frame construction. The purpose of this study is to calculate the PC member assembly time using the mathematical algorithm of PC member assembly. The results of this study can be used as basic data to calculate the construction date of the standard floor of PC construction.

This paper investigates the applicability of movable sensors that can be attached to hard hats to protect construction site safety management to prevent safety accidents based on accident case studies in the field of construction engineering and the gas sensors currently used in construction sites. We would like to propose MQ-2, a standard Arduino gas sensor.

Existing modular research has been mainly focused on S (shelter structure) and I (infill interior finishing material), and considerable research has been conducted, and the results are being proposed. However, in the case of the rest (exterior materials and windows, etc.), existing construction methods and materials are borrowed, and supporting hardware members and insulation materials are constructed on site, which acts as a factor hindering overall shortening of the construction period. That is, since the advantages and characteristics of modularity cannot be utilized in the absence of modular cladding, manufacturing of cladding is required. Therefore, it is necessary to develop a cladding system that can drastically reduce the construction period in factories while considering the structural characteristics of PC modulars.

Despite the acuuracy, stability, and economic feasibility of geomagnetic field-based indoor positioning, its applicability in construction sites needs to be thoroughly discussed due to the issue of distortion of geomagnetic fields around ferromagnetic objects such as rebars. In this study, the possibility of applying the geomagnetic field-based indoor positioning in construction sites was reviewed through the Student's t-test after measuring the changes in geomagnetic field values depending on the presence or absence of rebars. The statistical analysis revealed that there is a high probability (over 80%) of significant changes in geomagnetic field values when measuring points are located within 60cm from the rebars. On the other hand, the probability of minimal changes in geomagnetic field values is over 90% when measuring points are located more than 60cm from the rebars. This suggests the application of geomagnetic-based indoor positioning in construction sites would be possible if the issue of distortion in geomagnetic field values near rebars within 60cm is resolved.

Recently, heat island and dry island phenomena occur frequently due to land surface development and excessive energy consumption in urban areas. As a result, the surface temperature of the building and the entire temperature of its surroundings are increased, and as a result, the durability of the building is rapidly deteriorated. In order to suppress these causes, a method of maintaining the temperature of road heating wires was implemented as a temporary measure, but this did not predict climate change. Therefore, this study is a method to measure the compressive strength, density, and thermal conductivity of lightweight concrete using waste glass foam beads. After fabricating a simple chamber, the temperature and humidity of the inside and outside were measured with an Arduino device in consideration of external factors. Therefore, if waste glass foam beads made through proper mixing are constructed in the urban center, the quality of the urban can be improved.

The construction industry is increasingly adopting vision AI technologies to improve efficiency and safety management. However, the complex and dynamic nature of construction sites can pose challenges to the accuracy of vision AI models trained on datasets that do not consider the background. This study investigates the effect of background on object recognition for vision AI in construction sites by constructing a learning dataset and a test dataset with varying backgrounds. Frame scaffolding was chosen as the object of recognition due to its wide use, potential safety hazards, and difficulty in recognition. The experimental results showed that considering the background during model training significantly improved the accuracy of object recognition.

The compressive strength of concrete is greatly affected by the temperature inside the concrete at the initial age immediately after pouring. In the KCI Concrete Standard Specification, only the temperature correction strength (Tn) according to the curing temperature is applied in the mixing strength calculation formula, and mSn is not considered. The formula based on the Chrino model of the blast furnace slag concrete was calculated, and the strength of the structural concrete and the strength of the water cured specimen in the same mixture were compared with the predicted strength. As a result, the error between the predicted strength and the measured strength was greater in the structural concrete than in the concrete specimen.

Recently, the construction industry has seen the emergence of interior and exterior finishes using ultra-high performance concrete (UHPC) and colored concrete products using precast concrete (PC). However, the excessive amount of pigment used for coloring reduces the strength of the concrete. There is a need to improve the durability and chromaticity of colored concrete, and further analytical studies on the properties of colored concrete are also required. Therefore, in this paper, colored ultra-high strength cement composites (C-UHSCC) containing red and green inorganic pigments were prepared, and the compressive strength and color of the specimens were measured according to the age, and the correlation between strength and color was analyzed by simple linear regression analysis using R² value. The results showed that the red color was highly correlated with L^* and a^*, and the green color was highly correlated with a^*. These results can be considered for various concrete formulations, but research is needed to suggest the optimal pigment mixing ratio for proper strength and color development.

In general, all buildings are equipped with various types of handles for opening and closing the door, and unlike wooden doors, steel doors such as fire doors are equipped with a box-shaped door lock box frame surrounding the outside of the door lock to protect the door lock, which is called a cylinder protection cover. These cylinder protection covers have various types and types of fastening structures, and the cylinder protection covers on the market are molded in factories and standardized according to the size and shape of the door lock, requiring various types of cylinder protection covers. Accordingly, a variable cylinder protection cover with a simple prefabricated structure that can fundamentally solve these problems can be used as one cylinder protection cover regardless of the type, shape, and size of the door lock.

In this study, a concrete was prepared using an alkaline aqueous solution produced by electrolyzing potassium carbonate in order to improve the low initial strength of concrete using blast furnace slag. In order to confirm the increase in initial strength, the compressive strength of specimens was measured on the age of 7, 28 days. As a result, the blast furnace slag concrete using the electrolysis alkaline aqueous solution as the mixed water show high strength more than the blast furnace slag concrete using the general mixed water.

This study proposed the optimal mixing time for pre-mixed cement and post mixed cement using the statistical analysis method of box plots. Pre-mixed cement can prevent material seegregation, strength loss, and quality variation if mixed for at least 60 seconds, and the data median is shown to be within the box range. Post-mixed cement should be mixed for at least 180 seconds to prevent material segregation, strength loss, and quality variation, and compressive strength tends to increase with longer vibrating times. Therefore, it is suggested that using pre-mixed cement can shorten the vibrating time and increase the productivity of the concrete.

In this study, red mud with low recyclability was manufactured as liquid red mud, neutralized with sulfuric acid and nitric acid, and then added to cement paste to conduct research on physical and chemical properties. As a result, liquid red mud-added cement paste neutralized with sulfuric acid and nitric acid showed higher compressive strength after one day than cement paste with plain and non-neutralized liquid red mud. This indicates that nitric acid and sulfuric acid neutralization can increase initial strength.

In this study, the strength development characteristics of calcium silicate cement mixed mortar according to carbonation hardening conditions were evaluated. As a result of measuring the compressive strength, the strength increased according to the carbonation hardening time, and the strength increase rate was higher for the specimen with a CO₂ concentration of 20%.

This study aimed to evaluate the feasibility of estimating the setting time and compressive strength in Ternary Blended Concrete(TBC) using Settimeter, Strength meter, and Hybrid meter. It was determined that the hardness values at the initial setting time and final setting time of Settimeter, Hybrid meter, and at the 5 MPa of Strength meter were not affected by the mixing ratio of TBC. However, future studies need to consider the errors caused by the instability of the measurement surface during condensation and the state of the measurement surface after hardening.

In this study, the effect of hybrid fiber reinforcement on the residual strength and impact resistance of high-strength cementitious composites exposed to high temperatures was investigated. A cementitious composites was manufactured in which 0.15 vol% of polypropylene fiber (PP) and 1.0 vol% of smooth steel fiber (SSF) were double-mixed, and a residual strength test was conducted while thermal stress was applied by heating test, and then a high-velocity impact test was performed. In the case of general cementitious composites, the rear surface is damaged due to explosion and low tensile strength during high temperature or impact, while hybrid fiber reinforced cementitious composites can repeatedly absorb and distribute stress until multiple fibers are damaged to suppress the propagation of impact and resistance to explosion. Therefore, this study analyzed the residual strength of cementitious composites exposed to high temperatures depending on whether hybrid fibers were mixed or not, and collected research data on fracture behavior through high-speed impact tests to evaluate impact resistance and mechanical properties.

Steel doors, which are common in general buildings, do not seal the gap between the door and the floor, so drafts, noise, dust, and lights flow from the outside, and shielding devices are installed in various materials and methods, such as adding magnetic gate paper to the side of the door or installing a gasket under the door, but performance is limited. Accordingly, in order to fundamentally solve these problems, we researched and developed a double gap blocking device that can improve fire resistance and airtightness performance in steel doors. Unlike general products, the double gap blocking device has the advantage of maximizing airtight performance by forming an air layer in the center when the door is closed, as well as greatly improving the fire resistance performance, which is the basic performance of the fire door.

Although concrete is a material widely used in the construction industry, it is very vulnerable to cracking and has a disadvantage in that durability deteriorates when cracks occur. When cracks occur, harmful factors are introduced through the micro-cracks of the structure, reducing durability. Therefore, in this study, as part of a study to alleviate the problems of maintenance and durability deterioration due to cracks in concrete structures, the mechanical properties of self-healing mortar according to the size of the capsule made of cement material were reviewed.

This study investigates the effect of nano-silica and nano-calcite on the hydration properties and mechanical performance of limestone calcined clay cement (LC³) paste. The pastes were synthesized by replacing limestone with nano-silica and nano-calcite in order to enhance the mechanical properties in both early and late stages of hydration. The nano-calcite enhanced the strength of LC³ pastes at 1 day of hydration, however, the strength decreased compared to the ordinary LC³ pastes afterwards due to excessive amount of carboaluminate produced in the pastes. On the other hand, nano-silica improved the mechanical properties of LC³ pastes at all ages of hydration. This is mainly due to the nucleation effect and pozzolanic reaction of nano-silica, affecting the early age and late ages of hydration, respectively. The nucleation effect of both nanomaterials were confirmed by the analysis of hydration heat, supporting the enhanced early age strength of nanomaterial incorporated LC³ pastes. Furthermore, the dense matrix was shown in the pore size distribution, and the increased C-S-H due to the pozzolanic reaction evidence the improved compressive and splitting tensile strength of nano-silica incorporated LC³ pastes.

Neglected buildings for long period can seriously reduce the durability of the building due to rust in rebars and deterioration in concrete quality due to exposure to outside air, and the seriousness of suspended buildings such as safety accidents and social crimes is emerging due to poor management. In this study, various problems such as the occurrence of safety accidents were analyzed through a fact-finding survey of buildings that have not been maintained due to long-term neglect in all areas of Jeju. In order to reuse a building that has been discontinued, the safety of the building structure itself must be checked. After securing safety through durability investigation, construction should be resumed or converted into a normal building through re-purposing, dismantling, remodeling, etc.

This study aims to analyze the factors that cause differences in the evaluation results of the life cycle carbon emissions assessment of buildings in both Korea and China as part of the methodology research of building life cycle assessment for Chinese buildings to promote building life cycle assessment in China. Specifically, it examines the building LCA standards of Korea and the standard for building carbon emission calculation in China as mentioned in the green building certification systems of both countries. Based on the investigation of the two standards, the life cycle carbon emissions of the evaluation target building were evaluated using the building life cycle assessment methods of both countries, and the influencing factors that cause differences in the life cycle carbon emission assessment results of the two countries were analyzed.

Building Information Modeling (BIM) design has been mandatory in Korea since 2016, and it has been gradually expanding in the industry, with a slow attempt to apply it in remodeling constructions. This is because Korea is facing a situation where many buildings are over 30 years old and require remodeling or reconstruction. The remodeling industry is also a growing market, as it saves construction time and cost compared to reconstruction. BIM is an ideal technology element for a competitive remodeling construction, as remodeling constructions face a complicated construction process from the start, including demolition, maintenance, and reinforcement to save the change process. However, there are still limitations in applying BIM to remodeling constructions, due to considerations of the existing building and the complicated requests of the inhabitants. BIM still has technical and environmental limitations for general use. In this study, I analyzed BIM application cases from existing studies and suggest what improvement points should be strengthened.

Mainly, this research is consisted management of construction works. And this research is explained how make manage of workers health and methods of safety work in construction sites. As a result, writter researches to make ideas for manage to use that analyse each type of workers they are old workers, foreigner workers and general technicians.

The construction inspection is conducted by the contractor or construction supervisor after a certain stage of work has been completed. As the consturction inspection task is dependant on construction schedule, however, it is difficult to plan inspection task systematically, resulting in increased supervision costs, delays in construction, and disputes. Therefore, this study aims to integrate inspection work with schedule management to systematize inspection procedures. Firstly, the inspection work is defined based on the construction supervision checklist. Then its relationship with the construction process, required time, and resources for inspection tasks are defined in construction schedule. Lastly, a process management program is used to assess the effects of applying the inspection work and examine changes in the overall construction period and process management. The proposed method in this study can support to plan construction inspection more systematically and to improve the effectiveness of construction quality management.

The technical proposal bidding system emphasizes the evaluation of the construction company's technical capabilities, with the aim of improving the quality and cost-effectiveness of the construction. However, in the VE analysis and proposal process for technical proposal bidding, the ideas are often reused from similar past construction projects, and the application of new construction technologies/methods is often lacking. Therefore, this study proposes a methodology for managing VE proposal information by integrating it into a BIM model using parametric modeling. This research developed database based on the existing VE proposals and new construction technology/method information from the Korea Institute of Civil Engineering and Building Technology. And by using parametric modeling, the proposed method integrate the VE database with BIM model. The methodology proposed in this study is expected to improve the reliability and effectiveness of VE-related idea proposals in technical proposal bidding.

Free-form Concrete Panel(FCP) is each panel that composes the concrete exterior skin of Free-form building. FCPs contain curved surfaces, and FCPs have different curvature, size, and angles. In order to manufacture FCP, high technology is required, and it is currently difficult to manufacture it according to the design shape. In particular, many errors occur in the side shape of FCP. This is because when the side silicone mold is applied, it is installed without a coupling method between molds and support device. In this study, basic research was conducted to develop a side silicone mold support device to solve the above problems. We classified the required performance and derived the detailed requirements. Also, Based on this, we drew the basic design of the support device. We plans to conduct design improvement, mock-up making, and FCP manufacturing experiments through future research.

Construction of reinforced concrete structures required massive amounts of concrete and steel rebar. The current procedure to estimate the quantity of rebar requires tedious and time-consuming manual labor. Consequently, this circumstance made the engineers vulnerable to error and mistake, which led to the rebar waste. No system that is capable of automatically calculating rebar length has yet been developed Thus, this study proposes a preliminary investigation of automatic rebar length estimation of beam element by using BIM-based shape codes drawn in Revit. Beam is chosen due to its complexity in the rebar arrangement. In addition, the development of this study could assist engineers on the construction site and effectively contribute to the minimization of rebar waste in the future.

In this study, light-heat generating materials were produced in two ways, and the performance of two light-generating insulation sheets was reviewed. As a result of the experiment, it was possible to confirm the improved heating performance of the light heating insulation sheet compared to the existing bubble sheet. The light heat insulation sheet (b) showed improved thermal properties compared to the existing bubble sheet, and it is believed that the temperature has increased due to the combined effect of initial hydration heat and heat generation after installation. In future studies additional experiments are needed to compensate for the insufficient insulation performance due to the single bubble sheet through the double bubble sheet and to adjust the amount of light-generating materials added as a consideration of the optimal heat-generating effect of the light-generating insulation sheet (b).

In order to reduce crack defects caused by the behavior of concrete during floor tile construction, this paper introduced a hybrid floor adhesion system that first constructs an organic adhesive with crack correspondence and attaches tiles with inorganic mortar.

In this paper, we introduce a model for detecting Personal Protective Equipment (PPE) using YOLO (You Only Look Once), an object detection neural network. PPE is used to maintain a safe working environment, and proper use of PPE protects workers' safety and health. However, failure to wear PPE or wearing it improperly can cause serious safety issues. Therefore, a PPE detection system is crucial in industrial settings.

The masonry structure is constructed by cement mortar binding material of brick objects and uses reinforced hardware(connected hardware or wall tie) together when building. However, over time, the corrosion of reinforced steel and the deterioration of joint mortar as well as bricks cause the risk of collapse. In particular, when the externally decorated brick wall is installed on the concrete girder for each floor, the angle bracket is not constructed or corroded, the full-layer weight load is applied to the wall of 0.5B, which is an example of full-scale or collapse. As a result of the evaluation, it was confirmed that the performance was improved compared to the existing bracket, and we plan to carry out a real-life test and long-term performance review of the building using the bracket in the future.

In this study, the mass production process was simulated using a 1m³ batcher plant to evaluate the application of high-strength fire resistance concrete. The strength ranges of concrete were set to 50, 60, 70, and 80 MPa, and each concrete mix proportions was selected through preliminary experiments in the laboratory. For the selected concrete mix proportions, after the mixer load value was stabilized in the batcher plant, the slump flow and air content of the fresh concrete were evaluated, and the compressive strength was evaluated up to 56 days. As a result of the experiment, both the slump flow and air content of the fresh concrete satisfied the target performance, and in the case of compressive strength, 50 and 60 MPa satisfied the target performance at 28 days and 70 and 80 MPa at 56 days.

In this study, the performance of the prediction model was compared and analyzed using DNN and LSTM learning models to predict the amount of dry shrinkage of the concrete. As a result of the analysis, DNN model had a high error rate of about 51%, indicating overfitting to the training data. But, the LSTM learning model showed a relatively higher accuracy with an error rate of 12% compared to the DNN model. Also, the Pre_LSTM model which preprocess data, showed the performance with an error rate of 9% and a coefficient of determination of 0.887 in the LSTM learning model.

The purpose of this study is to enhance the photocatalytic properties of a mixture of low-cost titanium dioxide and calcium carbonate through a simple mixing process. To increase the photocatalytic activity, the weight ratio of titanium dioxide to calcium carbonate was selected as a variable. Photocatalytic activity was evaluated by measuring the degradation of methylene blue and NOx under ultraviolet light. The results showed that a mixture containing 60% titanium dioxide and 40% calcium carbonate exhibited the highest photocatalytic activity.

The purpose of this study is to compare and analyze the effect of type and volume fraction of fiber on the electrical conductivity and shielding effectiveness of cementitious composites. The large specific surface area of amorphous metallic fiber, as well as the high number of fibers per unit weight, provided an advantage in the formation of conductive path. As the result, the electrical conductivity of amorphous metallic fiber was evaluated to be higher, and the shielding effectiveness was also higher. However, the shielding effectiveness according to electrical conductivity was confirmed to have a threshold point, and further research is needed to improve it.

Recently, a lot of nano-scale material technology development and research have been conducted in construction fields to improve the compressive strength and durability of cement-based Composites. There are some studies that have confirmed the properties and application effects of cement-based complex using each nanomaterial, but development and research using both materials are relatively limited. This study sought to confirm the effect of multi-wall carbon nanotubes (MWCNT) and nanosilica, which are representative construction nanomaterials, on the compressive strength, voids, and microstructure formation of cement. The purpose was to produce a cement composite by changing the mixing rate of the two nanomaterials, and to find the optimal mixing amount considering its mechanical and rheological properties.

In this study, the analysis of concrete cracks was conducted with a total of three variables: coating thickness, oxygen diffusion rate, and reinforced diameter of reinforced concrete structures. Cracks occurred after about 3, 4, and 6 years at the coating thickness of 30, 40, and 50mm when the coating thickness was used as a variable, and cracks occurred after about 4, 5, and 10 years at oxygen diffusivity of 2e-9, 2e-11, and 2e-12 (m²/s) when the oxygen diffusion rate was used as a variable. In the case of reinforcing bar diameters, cracks occurred after about 4, 3, and 2 years on the reinforcing bar diameters of D10, D19, and D25.

Environmental pollution problems are occurring in Jeju Island due to negative treatment of basalt waste. Measures for various approaches and utilization measures are needed to solve the problem of waste stones that occur during basalt processing. In this study, the Properties of permeable blocks with basalt were identified and the applicability and functionality as building materials were reviewed. This experiment is basic data for evaluating the functionality of the permeable block by manufacturing permeable blocks using basalt waste stones and analyzing flexural strength and compressive strength. The higher the basalt waste stone replacement rate, the lower the flexural strength and compressive strength, but it was judged that 20% of basalt waste stone replacement rate that satisfies the minimum flexural strength (4.0MPa) stipulated in KS F 4419 was appropriate. In addition, additional permeability coefficient and absorption rate experiments tended to increase as the basalt lung stone replacement rate increased. Therefore, it is judged that the permeable block using basalt waste stone is superior to the existing permeable block.

In recent years, the use of high-strength grout has gained popularity in offshore wind power generation complexes for facility foundations and bridges. These marine wind farms require support for horizontal loads from wind and waves. To ensure the strength of the grout produced in environments similar to the actual placing site, this study investigated the curing of high-strength grout discharged through pump pressure in various environments, and examined the difference in strength according to different variables. Compressive strength measurements revealed that the core specimen collected from the bottom (3cm) and uppermost (50cm) of the specimen exhibited lower strength compared to other height specimens, while the core specimen obtained from the corner exhibited lower strength compared to the center. These findings suggest that the strength difference between the center and the corner is more pronounced when curing at low temperatures. This effect is greater than the strength reduction that typically occurs during low-temperature curing, and thus, necessitates careful attention in similar construction environments.

This study attempted to derive an appropriate application range by reviewing the integration performance of joints according to the application range of SRA concrete. As a result, it was confirmed that the integration performance was improved even if SRA concrete was placed only by 75mm, which is 0.5 times the thickness of the member.

In this study, the mechanical properties, alkali-silica reaction(ASR) expansion and residual mechanical properties after ASR of waste glass fine aggregate(GS) mortar according to mineral mixture were evaluated. As a result, it was found that the mineral mixture reduces the ASR expansion. However, mechanical properties and residual mechanical properties have decreased.

This study was conducted as part of research and development of high-strength grout. Accordingly, dolomite aggregate was used as a filler incorporated into the high-strength grout. Dolomite aggregate has a disadvantage of increasing the viscosity of the grout due to higher generation of fine powder than other aggregates. Accordingly, in this experiment, it was confirmed that the viscosity, flow time, and flow of high-strength grout change according to the volume composition ratio of dolomite aggregate and cement-based material. All experiments were conducted based on the Korean Industrial Standard KS F 4044, and the mixing factor was applied according to the composition ratio of the binder and the filler. In the experiment, the amount of fine powder contained in the dolomite aggregate rather than the silica sand used in the past is grasped, and after mixing with the grout accordingly, the mixture is proceeded to measure the viscosity in an unhardened state. In addition, the flow and flow time of the grout are evaluated according to the viscosity. As a result of the experiment, it was confirmed that the viscosity and flow time decreased and the flow increased as the volume composition ratio of the dolomite aggregate to the cement-based material increased.

This paper presents a study on the selection of optimal mix proportions for producing lightweight pre-foam concrete as a substitute for Autoclaved Lightweight Concrete (ALC) without the accelerated curing. The study was conducted using a rapid hardening binder made from by-products of the steel industry as the primary raw material. The experimental results established the optimal mix proportions, which included retarder content, water/binder ratio, foam content, and fiber inclusion amount, for the production of lightweight foam concrete. The optimal mix proportion was determined to have a retarder content at the minimum amount required to secure the working time, W/B of 35%, a foam content limited to 65% or less, and a fiber inclusion amount of 0.05% or less.

Recently, interest in concrete quality has been increasing. It is important to manage these factors due to unit-water content and aggregate quality that affect concrete quality. In this study, the unit-water content of concrete was measured through an economical, easy-to-measure, and portable Frequency Domain Reflecmetry sensor among micro-methods that compensated for the shortcomings of existing concrete unit-water content measurement methods. As a result of predicting the unit-water content, the accuracy within the ± 10 kg/m³ error range was confirmed to be more than 72% of all factors. In order to ensure high accuracy, it is considered necessary to conduct an experiment to evaluate the unit-water content by conducting additional experiments according to other variables and factors.

The construction industry is a hazardous environment in which many field workers work. Therefore, there is a limit to the safety manager's grasp of all situations. In order to solve these problems, the application of automatic control technology in connection with AI and CCTV is being introduced, and the development of intelligent CCTV to reduce the safety accident rate is actively progressing. This study seeks to present future directions by identifying the current status of intelligent CCTV developed to reduce the safety accident rate at construction sites and analyzing its limitations. Through this, the range of accident prevention types of the safety control system at the construction site will be confirmed and the need for future intelligent CCTV function development will be suggested.

This paper presents a new method for indoor localization track workers in construction sites. While GPS and NTRIP are effective for outdoor positioning, they are less accurate when used indoors. To address this issue, the proposed method utilizes Aruco markers to measure the distance between workers and the markers. By collecting data values, the location of each worker can be determined in real-time with high accuracy. This approach has the potential to enhance work efficiency and safety at construction sites, as it provides more precise indoor positioning compared to conventional methods, leading to improved work efficiency.

The procedure of predicting the construction cost and selecting the best alternative is performed based on comparative review of each building case. In the case of office building, it is required continuously until design is complete, since the owner requirements are various and likely to change during the design process compared to a standardized apartment. However, since the comparison work for each alternative in practice uses only the unit construction cost, there is no correlation between the alternative and the final result, and it is difficult to quantitatively determine the effect of the determined design factor on the total construction cost. It is needed that a means to support the generation of design alternatives using similar building cases during the design phase. This paper proposes a BIM-based data replacing process to support creating and comparison of design alternatives of internal finishing for office building. When design alternatives are created through the proposed process, it is possible to compare several similar cases with current project under equivalent design circumstance. Because only some finishing properties are replaced while maintaining the shape information such as the length, height, and base constraint of the object to be replaced.

A panic device is a type of door lock that opens when pressed or pushed by the body, so it is an emergency escape device designed to easily open the door and escape in an emergency situation such as fire or earthquake. It is an ideal door handle for an emergency exit. Because many people move quickly and it is easy to use, it is common in Europe and North America, but in Korea, the product is expensive, so it is used on a limited basis in luxury buildings such as hotels, but its use is gradually increasing. East Asian countries such as Korea, China, and Japan mainly prefer the North American type. The design of the penic device used in is a uniform and universal design, and research and development of a new design of the penic device was required to develop a new design type product considering the aesthetics of the building.

Building Information Modeling (BIM) design has been mandatory in Korea since 2016, and it has been gradually expanding in the industry, with a slow attempt to apply it in remodeling constructions. This is because Korea is facing a situation where many buildings are over 30 years old and require remodeling or reconstruction. The remodeling industry is also a growing market, as it saves construction time and cost compared to reconstruction. BIM is an ideal technology element for a competitive remodeling construction, as remodeling constructions face a complicated construction process from the start, including demolition, maintenance, and reinforcement to save the change process. However, there are still limitations in applying BIM to remodeling constructions, due to considerations of the existing building and the complicated requests of the inhabitants. BIM still has technical and environmental limitations for general use. In this study, I analyzed BIM application cases from existing studies and suggest what improvement points should be strengthened.

Positioning information of workers is important for safety management at construction sites. Among the various indoor positioning technologies, geomagnetic fields-based technology is more economical and has less error than other technologies. However, there is a problem that the installation and dismantling of materials such as formwork at construction sites can cause degradation in positioning performance. Therefore, in this study, the distortion of the geomagnetic field near euro-form was quantitatively measured and the application method of geomagnetic field-based indoor positioning technology on formwork stage was presented. The results showed that the distortion occurred within 10cm of the wall and column form, but positioning accuracy could be affected up to 60cm from the form due to the characteristic of geomagnetic field-collecting technology. Therefore, applying this technology to the formwork stage requires complementary measures, such as using other positioning techniques up to 60 cm near the formwork, or excluding distorted area when positioning. It is expected that this study can contribute to the efficient safety management of workers by suggesting ways to prevent an increase in positioning error when applying geomagnetic field sequence-based indoor positioning technology during the formwork stage.

As the introduction of new climate system, efforts to change carbon neutrality, efforts to convert carbon neutrality. In Korea, we are setting up carbon emissions through greenhouse gas and energy target management system for business and companies that emit carbon emissions. The construction industry quantitatively predict the carbon emissions, but it is struggling to set up the amount of carbon emissions before construction stage, but it is suffering from lack of data. Therefore, this study was conducted by collecting data on the energy usage amount of carbon emissions according to the energy usage of the construction phenomenon and low-capacity prediction of the construction phenomenon. Through collected data, the average energy usage amount by building users and evaluated the average carbon emissions. It also evaluated the contribution of carbon emissions by energy sources.

In modern architecture, tiles are used as a decorative material to enhance the appearance of buildings. However, defects occurring during tile installation affect not only the appearance of the building, but also its maintenance. This study aims to investigate stable tile installation by producing tile modules using the floating mortar method and conducting freeze-thaw tests to measure their adhesion strength. Test results showed that the adhesion strength increased as the mesh size decreased, except for S3 mesh. This study highlights the importance of research on tile installation to solve problems related to building appearance and maintenance.

The thermal conductivity of the insulation material has a great influence on the heat transmission coefficient, which is currently used for energy evaluation of buildings. The thermal conductivity of insulation changes with changes in the environment, such as humidity and ultraviolet rays, and can be expected to with the passage of time. But there is a lack of data on this, so this study measured the thermal conductivity of organic insulation according to environmental conditions and time, As a result, in the case of XPS, the thermal conductivity value increased over time, which is estimated to be due to the decrease in insulation performance as the foaming gas escapes to the outside, and in the case of PIR class2 No.2 and PIR noncombustible, the increased thermal conductivity value is similar, but in the case of PIR class2 No.2, a relatively moderate increase can be seen, and in the case of PIR noncombustible, a large increase is seen at the beginning, which is judged to be due to the decrease in insulation performance as the internal foaming gas is substituted with air from the outside.

The purpose of this study is to analyze the applicability and limitations of SPOT robots in the construction industry. The SPOT robot, which is being introduced to construction sites for smart construction with the progress of the 4th industrial revolution, is shaped like a four-legged dog and is equipped with various sensors for data collection and autonomous driving. In this study, hardware and software were analyzed, such as the size of the SPOT robot, mobility on slopes and heights, operating environment, and software functions that can collect data with a sensor weighing up to 14 kg. In addition, while the SPOT robot operates in a construction environment, performance such as stability, accuracy, signal connection distance, and obstacle avoidance are evaluated, and the applicability and limitations of the SPOT robot in the construction industry are analyzed. Based on this analysis, the purpose of this study is to evaluate when and how SPOT robots can be effectively used at construction sites, identify limitations, and derive contributions and improvements for the construction industry.

Optimal fleet management in the planning stage is one of the most critical activities that guarantee successful construction projects. In South Korea, the construction standard production rate database (CSPRD) is normally employed. However, when it comes to a trade-off problem that involves decision-making on optimal sets of equipment to perform a certain task, the method will require the planners' in-depth knowledge and experience regarding the target process and a time consuming estimation of the performance of every possible scenario must be conducted for the deduction of the optimal fleet management. On this account, this research paper proposes a lightweight method of using mixed integer nonlinear programming (MINLP) in multi-objective problems based on CSPRD-based mathematical equations to assist planners in the preplanning stage of choosing the optimal sets of types and size machinery to efficiently arrange the construction scheduling and budgeting.

This study is tocompare and analyze the results of hydration heat analysis and on-field measurements using the method with hydration heat difference and insulation curing method for controlling hydration heat in mass concrete. As a result of the analysis, the temperature difference between the center and the surface was predicted very similarly, and the mass concrete surface was controlled to a safe level when evaluating with a temperature crack index, and after being finished, it was confirmed that there was no hydration crack.

In this study, the hydration heat differential method was applied to mass concrete structures, and the hydration heat analysis was compared and analyzed with on-site measurement results. The results showed that the temperature history measurements of mass concrete were managed at a difference of 8.4 ℃, and although there was some deviation in thermal stress, a similar trend was observed. Consequently, it was determined that the thermal stress on the surface of mass concrete is less than its tensile strength, which would prevent the occurrence of thermal cracks.

With taller buildings and larger typhoons, the impact of building winds is growing. During the 11th Typhoon Hinnamno in 2022, the building wind in Busan L City exceeded 60m/s, reaching the highest speed ever. Although many studies have been conducted on reducing the wind load of buildings, which is one of the problem factors caused by strong wind speed, there is a lack of research on wind speed reducing sculptures that can directly control strong wind speed. In this paper, several types of wind speed reduction sculptures were proposed to solve these problems, and the wind speed reduction capability of the proposed sculptures was analyzed through computational fluid dynamics (CFD). These results can contribute to suggesting effective design methods for improving the urban environment and reducing pedestrian stress.

This paper confirms the application sites of dry coupler technology, which is a direct connection method using screw threads, and Unlike wet couplers, this method can stand on its own without proof support and continuous work on the upper part. Furthermore, concludes with personal considerations to improve constructability.

Concrete surfaces have weak surface strength due to bleeding and laitance, and problems such as peeling, cracking, and cracking may occur. In particular, underground parking lots can be said to be more vulnerable to peeling, breaking, and cracking if excessive loading of materials and equipment movement are not managed at the initial age after placing of concrete. Cracks, peeling, and cracking problems in slab concrete in underground parking lots of apartments can lead to leakage problems and affect finishing materials constructed on top of topping concrete, reducing the performance required for waterproof materials. Therefore, in this study, the bleeding and surface strength according to the standard of topping concrete and the use of admixture were reviewed to solve the crack, peeling, and cracking problems among the types of defects in underground parking lot slab concrete. As a result, it was derived that the optimal concrete compressive strength is 30MPa or more, and it is a reasonable performance design method to prohibit the substitution of admixtures.

When primer is applied manually, adhesion performance decreases due to a decrease in primer penetration performance on the surface, and construction period delay may occur due to a long time due to a decrease in work efficiency when a large area is worked using a conventional roller. In addition, in the case of the roller method, precision work in corners and narrow spaces is not possible, so it is urgent to come up with measures to ensure uniform quality. In addition, secondary work occurs to remove fine powder from the surface before primer application, resulting in construction period delay due to the rise of the working stage. Therefore, in this study, equipment was used instead of manual work for primer work, and as a result, penetration performance and adhesion performance were improved about twice. From these results, it was confirmed that favorable results such as improving work speed, securing high quality, improving the working environment, and resolving the shortage of functional workers can be obtained.

In this study, concrete pumpability was investigated using a sliding pipe rheometer when the slump was different, and the cause was analyzed by comparing the actual field pump pressure. As a result of the experiment, it was found that the concrete pumpability was greatly affected by the slump measurement value.

In this study, the bond strength characteristics of cement liquid waterproofing are confirmed. Investigation was made on the properties of adhesion strength due to cement liquid waterproof construction methods and changes in curing temperature. It is intended to reduce the possibility of tiles falling off by ensuring the adhesion strength of the cement liquid waterproofing.

Noise, dust, etc. caused by road pavement cutting work, which frequently occurs in new construction or reconstruction of buildings, construction of complexes, etc., are environmental hazards and cause civil complaints. Recently, an eco-friendly pavement cutter is being developed to make the work low in noise and dust, however, the on-site cutting performance of the equipment has not been quantified. In this study, in order to derive a standard value for comparing the cutting performance of the eco-friendly cutter under development, a conventional pavement cutter was applied to four residential sites in Seoul and Gyeonggi-do, and the cutting data was collected. As a result of analyzing the collected data, the conventional pavement cutter showed a cutting performance of 12.3 to 20.2 sec/m, and the average was 27.2 sec/m. In the future, additional cutting experiments with various mixing ratios, materials, and depths are planned to confirm the performance of conventional pavement cutter in more detail.

The unit curtain wall is an exterior finish currently used on the exterior walls of high-rise buildings. Curtain walls used as non-endurance walls are largely classified into stick curtain walls and unit curtain walls, and their use has recently been on the rise to reduce risks at construction sites through factory manufacturing. Accordingly, this study attempted to examine the insulation performance according to the shape of the unit curtain wall profile through insulation simulation.

The unit curtain wall is an exterior finish currently used on the exterior walls of high-rise buildings. Although the structural impact is not significant due to the non-strength wall, in the case of the unit curtain wall to which the factory manufacturing method is applied, deformation of the profile may occur according to its own weight. Therefore, in this study, stability is evaluated through design standard calculation applied when finishing the outer wall according to the design shape of the unit curtain wall profile.

The objective of this study is to evaluate the airborne sound insulation performance between housing units and community facilities during the construction phase. Community facilities adjacent to housing units can lead to noise problems, hence it is necessary to minimize noise transmission during the design phase. However, flanking noise transmitted through gaps of structures, windows, pipes, and other openings may result in substandard sound insulation performance falling below the design standards. Therefore, It is crucial to measure airborne sound insulation in the field during the construction phase. The measurement was conducted using the survey method for the field measurement of the airborne sound insulation in accordance with KS F ISO 10052:2021. Although the noise standards caused by community facilities in apartment complexes are not specified in current laws and regulations, desired noise level was set based on international guidelines for indoor noise. First, the level of noise generated in community facilities was estimated, and then the sound insulation performance was evaluated to determine whether the desired noise level was achieved.

As technology improves with the 4th industrial revolution, smart construction is becoming a key part of safety management in the architecture and civil engineering. By using object detection technology with CCTV data, construction sites can be managed efficiently. In this study, super resolution technology based on deep learning is proposed to improve the accuracy of object detection in construction sites. As the resolution of a train set data and test set data get higher, the accuracy of object detection model gets better. Therefore, according to the scale of construction sites, different object detection models can be considered.

The production plan of Precast Concrete members is closely related to the assembly plan of Precast Concrete members, and is an important management factor for the process planning of Precast Concrete construction. This may cause a delay in the construction period due to manufacturing errors occurring in the production process of members and transportation errors according to the production sequence. Therefore, it is necessary to have an efficient production plan for Precast Concrete members that can produce the necessary quantity from the point of assembly of the members and supply them in a timely manner. This study is a basic study for establishing a production plan for Precast Concrete members, and the purpose of the study is to examine the factors that affect the establishment of a production plan for Precast Concrete members. In this study, the influencing factors according to the production method and conditions when establishing a production plan for Precast Concrete members were considered. In the future, correlation analysis among influencing factors will be carried out, and it is expected that it will be used as basic data for schedule management of Precast Concrete construction and derivation of construction period calculation standards.

The development of corrosion inhibitors with outstanding performance is a never-ending and complex process engaged in by researchers, engineers and practitioners. Computational assessment of organic corrosion inhibitors performance is a crucial step towards the design of new task-pecific materials. Herein, electronic features, adsorption characteristics and bonding mechanisms of two pyridine oximes, namely 2-pyridylaldoxime (2POH) and 3-pyridylaldoxime (3POH) with the iron surface were investigated using molecular dynamics (MD), and self-consistent-charge density-unctional tight-binding (SCC-DFTB) simulations. SCC-DFTB simulations revealed that 3POH molecule can form covalent bonds with iron atoms in its neutral and protonated states, while 2POH molecule can only bond with iron through its protonated form, resulting in interaction energies of -2.534, -2.007, -1.897, and -0.007 eV for 3POH, 3POH+, 2POH+, and 2POH, respectively. Projected density of states (PDOSs) analysis of pyridines-Fe(110) interactions indicated that pyridine molecules chemically adsorbed on the iron surface.

As a result of examining research contents related to soil excretion being studied in Korea, there are five methods for soil excretion testing. As a result of analyzing the correlation between each test method and concrete compressive strength, the chemical test method and the Methylene blue test showed a high correlation index.

This study attempted to derive an appropriate application range by reviewing the integration performance of joints according to the application range of SRA concrete. As a result, it was confirmed that the integration performance was improved even if SRA concrete was placed only by 75mm, which is 0.5 times the thickness of the member.

Nanomaterials are being actively studied in the fields of cement and concrete. However, research on other nanomaterials is insufficient because much of the carbon-based nanomaterials are made up of carbon nanotubes. Therefore, in this study, carbon-based water-soluble graphene oxide was mixed into mortar according to the cement replacement rate to conduct a characteristic evaluation. As a result, as the substitution rate of graphene oxide increased, workability decreased, and there was no effect of enhancing compressive strength. In addition, it was confirmed that the compressive strength decreased due to a large amount of air bubbles when the mixture was mixed for the purpose of improving workability.

After January 2023, as part of the plan to realize housing stability for the people, the weights for each field of reconstruction safety diagnosis have been adjusted. Among them, the weight of the residential environment sector has been raised from 15% to 30%, so that it occupies a high proportion. The adequacy review will also be partially implemented if requested by the local government. Therefore, it is also required to improve the existing reconstruction safety diagnosis manual for rational review. In this study, we intend to examine the problems and points to be improved through the review cases from the introduction of the system to the present. Through this, it is intended to be used as basic data to approach changes in demand for reconstruction and future trends in the future housing market.

In this study, a mortar was prepared using Rhodobacter capsulatus which is forming glycocalyx and immersed in a simulated sewage environment. As a result of the experiment, it was observed that bacteria continued to grow in the mortar immersed in the simulated sewage environment, and it was confirmed that glycocalyx was formed by bacteria on the surface of mortar specimen.

Out of an estimated 7 million buildings nationwide, approximately 38% of them have been standing for over 30 years, and this number is expected to continue to increase. Additionally, due to the Building Act, safety inspections will be mandatory for approximately 70,000 buildings annually, leading to an increase in demand for building safety inspections. However, the current building safety diagnosis heavily relies on manpower, making it difficult to diagnose locations that are hard to access, and requiring lengthy investigation periods. Therefore, this paper presents the basic research results of a non-contact concrete damage depth estimation technique using laser technology aimed at remote building safety diagnosis and shortening investigation periods.

As facilities in apartment unit by age, residents feel uncomfortable in their lives, but maintenance and management are not carried out properly. For the systematic maintenance of facilities, the derivation of facilities that require maintenance shall be preceded. This study aims to derive items that require intensive management among exclusive facilities. The purpose of this study is to analyze the history of repairing facilities through complaints about the exclusive use of public rental housing to identify the cause and to derive items that require intensive management of the exclusive use of apartment houses.

In this study, we conducted a case analysis of the building finish and equipment deterioration sector in the validity assessment of safety inspection findings for reconstruction. A total of 21 cases were analyzed to confirm the characteristic of performance score for each subsector. It is confirmed that the average performance score was generally affected by maintenance activity, had regional characteristics.

Although there are many old school buildings that is more than 40 years in Korea, it is difficult to rebuild all of them due to limitations in budget management. Therefore, objective feasibility evaluation criteria are necessary to determine which school buildings should be rebuilt preferentially among the numerous old school buildings. One of the rebuilding feasibility evaluation items, economic evaluation generally requires documents such as construction statements and facility drawings. However, because most buildings older than 40 years do not have these documents, an economic analysis model that requires only basic building information should be developed. In this study, the economic analysis model that can be used for evaluating the rebuilding feasibility only with the number of years, total floor area, and structural information of school buildings was established. This model can contribute to the objective feasibility evaluation of old school buildings because it can evaluate numerous buildings on the same criteria based on basic building information.

In order to prevent disaster risks caused by building aging in advance, the prevailing opinion is that it is urgent to actively improve systems such as mandatory safety inspections, and to calculate risks and develop safety management systems due to building aging. The need for systematic risk management continues to be emphasized in the process of safety inspection and repair of old buildings, but the risk management and safety management techniques of each construction entity have not been established in practice. Accordingly, this study aims to analyze the vulnerability factors of aging buildings and provide basic data on the development of a risk rating calculation model for old buildings and the efficiency of safety management systems in the future.

The need for maintenance of bridge infrastructure is increasing due to aging, and the cost of maintaining the infrastructure must be calculated for effective budget distribution. Therefore, in this study, representative defects according to bridge superstructure type are derived to calculate the cost for each repair method. First of all, the representative bridges, PSCI girder bridge, Rahmen bridge, Steel box girder bridge, and RC slab bridge, were selected as superstructures using BMS data, and repair methods for defects were presented. In addition, the cost of the repair method by superstructure type was compared. This result is expected to predict total maintenance costs in consideration of the maintenance cycle.

Due to the deterioration of infrastructure, the importance of maintenance is continuously increasing. Therefore, an integrated maintenance method for various facilities is required. In this study, a maintenance priority determination method for integrated maintenance of roads and pipe network facilities was developed. It is possible to analyze attribute information by using GIS data of roads and pipe networks, and shape information can be used. This information is derived as quantitative figures for determining maintenance priorities. In the future, it is expected that facility maintenance can be further advanced in connection with maintenance method and quantity information for each facility.

The solid-state reference electrodes made of polyaniline-coated MnO₂ (SSRE-PAM) and their electrochemical characteristics were studied in simulated concrete pore solutions (SCPS) containing 0 and 3.5% NaCl. Saturated calomel electrodes (SCE) have been used to conduct electrochemical studies on the stability behavior of SSRE-PAM. Open circuit potential (OCP) and potentiodynamic polarization techniques were used to assess the corrosion performance of steel rebar exposed in SCPS with 0 and 3.5% NaCl using SSRE-PAM. The results demonstrate that the SSRE-PAM was capable of identifying steel rebar in a concrete environment that was either passive or active. Potentiodynamic polarization parameters such as E_corr and I_corr for steel rebar in SCPS containing 0 and 3.5%)NaCl are greater than that of the passive condition (0% NaCl). All the studies validate the importance of using SSRE-PAM for corrosion monitoring applications in concrete structures.

Green remodeling of pubic buildings for improving indoor environment and reducing energy consumption is increasingly promoted. The objective of this study is to measure and analyze for wall's thermal performance, thermal transmittance, of existing buildings. The method of this present study refered the ISO 9869-1 and is to measured heat flow, surface temperature of wall, and in/outdoor temperature over 7 days. And it was compared the calculated thermal transmittance with measured one. The measured wall's thermal transmittance value is about two times than the calculated thermal transmittance value.

The visualization of information serves as a valuable tool for facilitating communication and exchange of opinions among stakeholders by conveying information in an intuitive and clear manner. As a preliminary study of visualization for construction field, this study proposed a model for generating three-dimensional floor layout using 360-degree panoramic cameras. The model integrates the layouts by calculating normal vectors of the plane which has openings, and applying translation and rotation matrices between the normal vectors. The results of this study can contribute to improving communication in construction sites by incorporating visualization, and further to the digital transformation of the construction industry.

The inspection work at construction sites is one of the important supervisory tasks, which involves verifying that the building is being constructed by the numerical values specified in the design drawings. The conventional measuring method for inspection involves using tools or equipment such as rulers directly by the personnel at the site, and it is usually confirmed by vision. Therefore, this study proposes an model to measure numerical values on images of the construction site. Through the case study to measure the installation interval of jack supports, the proposed algorithm was verified the effiect and validity. The results of this study suggest that it can support inspection work even in the office, which may have been overlooked by on-site inspectors, and contribute to the digitization of inspection work at construction sites.

According to relevant laws, in the case of a construction project with a total construction cost of 30 billion won or more, a post-construction evaluation must be performed after completion. In addition, a post-construction evaluation report must be prepared and entered into the Continuous Acquisition & Life-cycle Support(CALS). As a result of reviewing the currently accumulated post-construction evaluation reports, since the report is not standardized, it is difficult for public project owners to write the report. It also hinders the post-construction evaluation and management center from verifying contents, analyzing data, and deriving meaningful results. In order to improve the convenience of the public owners who must conduct post-construction evaluations and the work efficiency of the center, evaluation factors were standardized and a standard post-construction evaluation report format for road construction was developed in Excel. Through this, the data in the reports will be effectively accumulated, managed, and analyzed, so that meaningful results will be produced and be helpful in future construction work.

In line with the advent of the 4th industrial revolution, project performance such as construction productivity and safety is being improved through the use of various smart technologies in construction projects. However, most studies focus on case analysis according to technology application, and research on performance impact and evaluation methods is insufficient. However, the performance impact of the use of smart construction technology can vary greatly depending on the capabilities and level of support of the organization using the technology. Therefore, this study aims to establish factors that affect the performance of smart construction technology utilization at the organizational level and analyze the performance impact relationship. The results of this study will provide the basis for establishing an organizational system and evaluating performance for the efficient use of smart construction technology in the future.

In accordance with recent changes in construction trends, interest in introducing the OSC, such as the Precast Concrete, is increasing in apartment buildings. In domestic studies, studies on the prediction of the construction period of PC apartment buildings through simulation have been conducted, but there is no study on the comparison of the construction period according to the actual construction of Precast Concrete(PC) and Reinforced Concrete(RC). Therefore, this study seeks to grasp the technology of the current PC construction method and to secure the original technology of project management through comparison of the absolute time of frame construction for PC and RC buildings composed of the same plane.

This study evaluated the compressive strength after making mortar with low cement composition for carbon-neutral steam curing to respond to climate change. Blast furnace slag, fly ash, and ultra-high powder fly ash were used as substitutes for cement. The cement substitute was used at 40% of the mass of cement, and after steam curing, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age. As a result of the experiment, at the age of 1 day, the mixture using only cement showed the highest strength, but from the 3rd day, the specimen using ultra-high powder showed a high strength development rate, followed by blast furnace slag and fly ash.

In the concrete industry, efforts are being made to reduce CO₂ emissions, and technologies that collect, store, and utilize CO₂ have recently been studied. This study analyzed the change in compressive strength after the accelerated carbonation test of Non-Sintered Cement(NSC) mortar. Type C Fly Ash and Type F Fly Ash were mixed in a 1:1 ratio and then mixed with Blast Furnace Slag fine powder to produce NSC. The mortar produced was cured underwater until the target age. In addition, an accelerated carbonation test was conducted under the condition of a concentration of 5 (±1.0%) of CO₂ gas for 14 days. The mortar compressive strength was measured before and after 14 days of accelerated carbonation test based on the 7th and 28th days of age. As a result of the experiment, the compressive strength was improved in all binder. In general, the compressive strength of NSC mortar subjected to the accelerated carbonation test was similar to that of Ordinary Portland Cement(OPC) mortar not subjected to the accelerated carbonation test.

In this study, the performance evaluation and structural safety of rainwater permeation detention block were analyzed. As a result, the compressive strength (19.3 MPa), flexural strength (5.2 MPa), and permeability coefficient (2.0 mm/s) of the eco-friendly prefabricated rainwater permeable detention block satisfied the KS F 4419 and SPS-KCIC0001-0703 and it was confirmed sufficient safety even under maximum load.

In this study, we aimed to identify changes in fire resistance according to the type of sleeves used for pipe penetrations and to examine their accreditation of fire resistance performance and use them as basic data. The test results of fire resistance according to the type of sleeve used in non-metallic pipe facilities showed that the temperature on the support side was higher for sleeves with higher thermal conductivity. For the temperature on the surface of the pipes, in the case of galvanized steel plates, steel pipes, and structures without sleeves, the highest temperature was observed after the expansion of the firestop material for 46 to 53 minutes and then decreased. PVC sleeves showed a steady increase in temperature until 53 minutes, after which the temperature did not increase further. In addition, for non-metallic pipes, the effect of the type of sleeve on fire resistance is considered to be insignificant because the lower part (heating direction of the furnace) under the support structure is cut off to block the heat during the two-hour fire resistance test.

In this study, the effects of NaOH and KOH alkali activators of various concentrations on the performance of alkali activated waste concrete powder (WCP) was discussed. The samples activated by alkaline solutions were cured for up to 28 days and then compressive strength test was performed. These samples were also characterized using various techniques to explore the phase evolution, and microstructural changes. Results showed superior performance of NaOH-activated WCP. Additionally, activation of WCP by 8M concentrated alkali solutions improved the strength, reactivity and microstructure of alkali activated WCP binder sample.

Recently, as the radioactive waste disposal facility becomes scarce, the importance of efficient disposal of waste from nuclear power plants is increasing. This study was conducted to utilize radioactive waste concrete powder as solidifying agent for radioactive waste treatment. Paste with an age of more than one year was used with a disk mill to have a particle size of 150㎛ or less, and treated at temperatures of 500℃, 600℃ and 700℃ for 2 hours. In order to simulate the radioactive cement powder, aqueous solutions of Di-water, CsCl 1M, SrCl₂ 1M and CoCl₂ 1M were used as blending water at W/C 0.7 and to improve fluidity, polycarboxylate type superplasticizer was used at 0.4 wt.% based on the weight of recycled cement paste powder. Characterisation was carried out using vicat method, strength and density.

This study, as part of a study to reduce carbon dioxide emissions from the cement industry, compared and analyzed microhydration heat and strength characteristics of no-cement composites using blast furnace slag powder as a binder and CaO, CaCl₂, Ca(HCOO)₂ and Ca(NO₃)₂ as alkali activators. As a result of the evaluation, considering the strength, it is judged appropriate to use CaO, CaCl₂ and Ca(NO₃)₂.

Slag and ash generally have a higher powder degree than portland cement, so workability may deteriorate under the same unit quantity condition, and strength and durability decrease when the unit quantity is increased. At this time, if an aggregate having a low water absorption and an appropriate particle size is used to recover the loss of strength, it can contribute to reducing the unit quantity of the binder. Therefore, for the purpose of improving the workability and strength of non-sintered cement mortar using slag and ash, ferro nikel slag whose particle size was adjusted was used as an aggregate and its applicability was identified. In this experimental condition, it was confirmed that non-sintered cement mortar tends to improve workability and secure strength when ferro nikel slag having various particle size distributions is used as an aggregate. This can be analyzed as the effect of ferro nikel slag material properties including glassy properties and mixing conditions with a wide particle size distribution.

In this study, porous concrete with improved functionality was developed by using superabsorbent polymer (SAP) to provide rooting space for plants. The depth of settlement and mass change according to the substitution and addition rate of SAP were determined by investigating the functional performance of SAP and the volume change upon saturation. Test results indicated the depth of penetration settlement increased as the substitution rate of SAP increased, but the mass change could not be confirmed as the addition rate of SAP increased. The instability of the specimens due to the excessive volume change of SAP, as well as the osmotic pressure phenomenon according to the pH concentration, were identified as the cause. Therefore, future studies are needed to investigate the appropriate substitution and addition rate of SAP, as well as to reduce the osmotic pressure phenomenon according to the pH concentration, which would contribute to the improvement of the functional performance of vegetation concrete.

This paper summarized the safety diagnosis method in the field of durability among the structural safety suggested in the safety diagnosis manual of the reconstruction project and analyzed the safety diagnosis case. It is expected to be a reference material for safety diagnosis in the field of durability by pointing out cases that are wrong during existing safety diagnosis and cases where diagnostics are likely to make errors.

In the present investigation, the chloride ion penetration resistance of nuclear power plant concrete with varying water-to-cement ratios was assessed. A comparative analysis was conducted on concretes that do not incorporate supplementary cementitious materials, such as fly ash, using permanently decommissioned nuclear structures as a reference. The objective is to employ this acquired data as a fundamental resource for the evaluation of the residual service life of nuclear power plant structures in subsequent studies.

This study is part of the carbonation degree DB accumulation through quantitative analysis of carbonation depth, Ca(OH)₂ and CO₂ according to the type of finish and years of use of old concrete structures in order to predict the amount of CO₂ that can be absorbed through carbonation of concrete. To this end, the depth of carbonation of the concrete core specimen is measured using an indicator, and the dry amount of water combined with CO₂ in the sample is measured using a differential thermal gravimetric analyzer for samples in the carbonation area and non-carbonated area classified by the indicator, and the absorption compared to the weight of the sample. The amount of absorbed CO₂ was calculated. In addition, the degree of carbonation was calculated through quantitative comparison of Ca(OH)₂ in the carbonation section and non-carbonation section. In the future, we will continue to add the survey and analysis data of dismantled structures and use them as basic data for estimating the amount of carbon dioxide that can be absorbed according to the exposure conditions and years of use by concrete mix.

In a reinforced concrete structure, coupler construction is easier to install than jointing or welding reinforcing bars, so it is possible to work by one person. When constructing a reinforcing bar coupler, the coupler construction method must be different for each member that receives a large tensile force or a member that receives a small tensile strength. Various coupler products are used in the global construction market, and the quality, performance, and cost of reinforcing bar joints vary from product to product. This study compares and analyzes the quality and cost of representative rebar couplers according to the requirements using the quality house of QFD-HOQ. The case study presents a quality and cost improvements strategy through QFD-HOQ analysis of rebar couplers.

This study compared the compressive strength and healing strength to confirm the self-healing performance of mortar incorporating Bioinspired Self-healing Capsule (BSC) into cement composites as part of a study to mitigate the problem of durability deterioration due to cracks in concrete structures. As a result of the evaluation, it was found that the healing performance decreased as the mixing ratio of the BSC capsule increased.

The properties of cement mortar mixed with manganese-doped titanium dioxide nanowires (TiO₂(Mn)-NWs) were investigated in this study. The TiO₂(Mn)-NWs were synthesized using solvo-thermal synthesis and electro-spinning techniques. The TiO₂(Mn)-NWs at weights of 1%, ₂%, and 3% of the cement were respectively mixed into the cement mortar. The results showed that as the amount of TiO₂(Mn)-NWs increased, the flow value of the cement mortar was decreased and the setting time of cement mortar was accelerated. Moreover, as the amount of TiO₂(Mn)-NWs increased, the compressive strength of cement mortar was increased and the efficiency of acetaldehyde removal was improved.

This paper presents an experimental study on the bending behavior of Kagome truss composite beams reinforced by fiber-reinforced composites (FRC). Two types of FRCs, i.e., high ductile FRC with a high tensile ductility and high strength FRC with high compressive strength were used; and three Kagome truss composite beams reinforced by FRCs were manufactured. In order to investigate the bending behavior of beams, bending tests were carried out. Test results showed that types of FRCs and reinforcement methods significantly influenced the bending behavior of Kagome truss composite beams.

In this paper, the effect of change of sleeve type on fireproofing performance of through-penetration firestop system on metallic pipes was analyzed. As a result, if the material of the sleeve is high in thermal conductivity and thick, a large amount of heat is transferred to the top of the support structure.

The performance of the construction project is to be evaluated within 60 days of completion, according to relevant laws. It evaluates cost, construction period, design change, re-construction, safety, etc. for each project stage. And the project owners are inputting the evaluation results of the construction work into the construction project information system(CALS). The post-evaluation result information entered in this way can be referred to in the basic design of the construction project by referring to the related contents if there is a similar construction in the future. And It can also be used to predict and respond to the required period and cost by analyzing the accumulated data. In this study, in order to provide reference data that can be used in similar projects in the future, the latest analysis methods are reviewed and the possibility of future application is considered. Accordingly, this study intends to focus on the construction cost part among the indicators such as construction cost, construction period, design change, and re-construction that are currently being dealt with in post evaluation.

With the aging of buildings, the number and importance of regular inspections of buildings are increasing. The current safety inspection goes through a procedure in which a skilled technician visits an old building, visually checks it, takes a photo, and finally organizes and judges it at the office. For this, field personnel and analysis and review personnel are required. Since the inspection procedure includes taking pictures, a huge amount of data has been accumulated from the time digital photos were used to the present. When a model that can check cracks outside a building is developed using these data, manpower and time required can be greatly reduced. Therefore, this study aims to create a model for classifying cracks that occur outside the building through the artificial intelligence method. The created model can be used as a basic model for determining cracks only by external photography in the future, and furthermore, it can be used as basic data for calculating the size and width of cracks.

Interest in the commercialization of research results is increasing according to the recent social atmosphere. In the field of construction, new technologies are also being actively commercialized. Pre-analysis of products is an important procedure for future market entry. This study aims to conduct a product-based importance-performance analysis as one of the preliminary analysis methods for the commercialization of technologies developed in the field of construction and to explore their applicability. This study conducts a survey on those involved by setting the categories of product quality, convenience, and usability for the commercialization of previously developed pipeline inspection product. Based on this, we would like to present an analysis that calculates importance and performance of the product and helps to set the development direction through interrelationship analysis.

The military has adopted and implemented risk assessment since 2013 to reduce fatalities and accident rates at construction sites. However, risk assessment is carried out as a voluntary preventive activity and is maintained as a superficial administrative process for owners. Risk assessment must comply with the Occupational Safety and Health Act and the Enforcement Guideline of Risk Assessment. However, the scope of the assessment covers many industries, including manufacturing and distribution, making it difficult to apply to construction sites. As a result, the guidelines are interpreted and applied differently at each construction site. This study aims to improve the risk assessment system so that it is applicable to construction projects and proposes the improvement of the risk assessment system by analyzing the current status of serious accidents in military construction projects.

As the number of defects in apartments has increased recently, lawsuits and disputes related to defects have also increased. As a result, the loss of time and money is enormous. Therefore, fundamental measures are needed to reduce the occurrence of defects. Therefore, the purpose of this study is to propose a plan to reduce defects, focusing on window construction. To this end, existing studies were reviewed, and data from domestic construction companies were collected and classified to organize the types of defects. Based on the classified data, eight types with a high incidence of window glass were analyzed according to the time of occurrence, and the cause and causal relationship of the defect were schematized. It aims to identify the degree of possibility of recurrence of defects for each of the eight defect types for experts and derive key management elements using the RII method. Therefore, the goal is to select key management elements of window construction that actively reflect the characteristics of the construction stage.

Steel construction is one of the commonly used methods in building construction due to its efficiency in terms of time and cost. In particular, the top-down method using steel frames is widely used in the construction of underground structures in urban areas to shorten the construction period. However, there is currently no standardized cost estimation for subway steel frame construction in Korea, causing difficulties in determining the expected cost. In this study, we aim to provide basic data for establishing a cost estimation standard for subway steel frame construction through on-site surveys of subway steel frame construction commonly used in urban areas.

This study empirically validates whether the effect of strengthening the legal regulations in the construction industry under the 'Construction Business Act' is true in order to expand the direct construction of the comprehensive construction corporation. Checking the effectiveness of the legal regulation that can force direct construction of the required scope of construction will not only be a logical background in the strengthening of law regulations but also suggest arguments that contradict some construction companies called legal regulation.

In order to expand its entry into not only the domestic construction market but also overseas global markets, it is necessary to secure technological competitiveness, and as a fundamental measure, it is necessary to increase the proportion of R&D investment and establish and revitalize R&D organizations. Therefore, the purpose of this study is to analyze construction sales and construction R&D investment for global construction companies in Korea and Japan, derive implications, and provide basic data for government policy establishment and global construction company strategy establishment. As a result of analyzing R&D investments in construction companies in Korea and Japan, it can be seen that Japanese construction companies have higher R&D investment costs compared to sales compared to Korea. In particular, the proportion of R&D investment continues to increase year-on-year, strengthening global competitiveness due to technology development. In addition, Japanese construction companies have established a technology research institute to discover and conduct future R&D research such as advanced IT, disaster prevention, and environment.

As the shape and size of detectable objects diversifying recognition and segmentation algorithms have been developed to acquire accurate shape information. Although a high density of data captured by the repetition of scanning improves the accuracy of algorithms the high dense data decreases the efficiency due to its large size. This paper proposes standardization algorithms using the feature of structural members on indoor point cloud data to improve the process. First of all we determine the reduction rate of the density based on the features of the target objects then the data reduction algorithm compresses the data based on the reduction rate. Second the data arrangement algorithm rotates the data until the normal vector of data is aligned along the coordinate axis to allow the following algorithms to operate properly. Final the data arrangement algorithm separates the rotated data into their leaning axis. This allows reverse engineering of indoor point clouds to obtain the efficiency and accuracy of refinement processes.

In construction sites, small-scale construction quantities or limited work hours below the daily work volume may occur due to on-site conditions. For small-scale quantities, the input of equipment and labor is designed based on an hourly basis in the invoice, resulting in a difference from the actual cost. In this study, we aim to explore solutions from the perspective of construction cost standards to secure appropriate construction costs for small-scale and time-limited construction sites. Firstly, to preserve the basic construction costs on-site, we established standards where half the cost would be charged for construction quantities below four hours and a full day's cost would be designed for construction quantities between four to eight hours. Additionally, realistic construction cost calculation standards are expected to be provided by realizing a surcharge rate for work hour limitations to secure appropriate construction costs.

In the field of domestic construction, 3D modeling mainly targets outdoor construction sites, and acquires outdoor spatial information by operating UAVs and UGVs equipped with cameras. 3D modeling of construction sites tends to expand its scope to indoors along with the increasing demand for site monitoring and management through indoor spatial information. In the case of indoors, it is impossible to shoot with a drone after the framework and outer walls of the building are completed, so it is necessary to collect indoor spatial information and 3D modeling using a 360 camera. The purpose of this study is limited to basic research to establish a process that can obtain simple and high-quality indoor 3D modeling results using indoor data collected from 360 cameras.

In order to respond to changes in the industrial environment such as the 4th industrial revolution, university education also needs active educational innovation efforts. This study proposed a construction construction hybrid curriculum that can actively utilize online education in the direction of educational innovation in domestic universities. The hybrid curriculum was based on online learning through lecture videos used in team-based learning. The hybrid curriculum additionally allows learners to choose their learning methods. In a hybrid class, learners can choose the class participation method they want from offline classroom or online real-time. Hybrid classes are considered to strengthen learners' options and take a step forward in learner-centered education.

Improving productivity in industries is a very critical issue, and improving labor productivity is especially important in construction industry, which is a labor-intensive industry. However, researches on labor productivity in construction industry are insufficient, and most of previous studies have limitations in terms of specificity and logic. In this study, fuzzy DEMATEL method was used to structural analyze of influence factors for labor productivity in construction industry based on previous researches and expert survey. The result of this study contributes to deriving priorities for improving labor productivity.

The ripple effect is analyzed in the post-construction evaluation phase, but only the qualitative analysis and simple numerical fluctuations are analyzed, thus, no reliable ripple-effect analysis has been conducted. Therefore, in this study, a focus group interview was conducted with 10 experts to propose a plan to improve the ripple effect metrics. Consequently, by linking with the policy-effect metrics of the pre-feasibility study, it is expected that the utilization of the analysis results will be improved and objective and quantitative analysis will be possible.

Due to recent enhance of safety law and regulations in construction sites, safety inspectors have been more required in construction sites. However, most of them are novice for safety inspection which have not enough experience and skill. Therefore, the novice safety inspector's performance on hazard recognition needs to be improved for effective safety management. The performance of safety inspection is influenced by the inspector's experience and background because the inspection is usually conducted by the inspector's eyes. Therefore, there is a difference in safety inspection performance between novice and experienced safety managers. This study aims to analyze the gap of risk perception between novice and experienced safety managers using quantitative visual data. For this objective, this study conducted eye tracking experiments for novice and experienced group to evaluate cognitive performance of safety risk factors. The results provides the level of safety awareness based on their experience in construction safety. The limitation of this study is a lack of the number of samples used in this study and did not consider the various characteristics of the participants. If these limitations are supplemented in future research, it can be used to develop safety education contents for novice safety managers.

As data management and analysis technology advances, there is active discussion on how to utilize data generated in construction projects. Among them, the materials produced during the supervision work are highly useful because their generation cycle and format are regulated according to relevant laws. In this study, we analyzed whether the data produced during the supervision work in the construction phase of apartment housing can be utilized for project performance management. First, this study identified key data necessary for performance management through FGI with experts in the field of apartment housing. Next, we collected supervisory data from the case project and identified whether the data was generated, its cycle, and storage format. As a result of the analysis, the supervisory data contained various information that could measure the performance of construction projects and had the advantage of standardized data. In the future, utilizing supervisory data is expected to enable effective performance management of apartment housing construction projects.

In construction work, there is often a difference between the estimated construction period and the actual construction period. Accordingly, the project may be delayed from the scheduled date, leading to huge losses due to problems such as increased costs during construction. In this way, it is important to calculate the appropriate construction period at the project planning stage in construction work. To solve this problem, we would like to study a model that will increase the accuracy of the scheduled construction period at the project planning stage. This study compared and analyzed linear regression, Lasso regression, Ridge regression among the types of regression analysis to select an appropriate construction period prediction model to secure an appropriate construction period at the project planning stage to reduce problems during construction.

The tunnel construction projects is demanded more efficient risk management measures and loss forecasts to prepare for risk losses from an increase in the trend of tunnel construction. This study aims to analyze the risk factors that caused the loss of material in actual tunnel construction and to develop a quantified predictive loss model, based on the past loss record of tunnel construction projects.

The purpose of this study is to prevent dispute due to change orders in construction projects and to handle change orders smoothly. For this purpose, this study analyzed arbitration cases caused by change order handled by the Korea Commercial Arbitration Board. Based on this, dispute factors were analyzed and change order management factors and management plans were presented. Change order management factors were derived from responsibility, contract, design, process, construction cost, and schedule management, and a detailed management plan according to the relevant factor was presented.

Kiscon, Seumteo, KONEPS and CSI are representative construction-related DBs. All four DBs are operated by the public. However, the characteristics of data are different depending on the purpose. Therefore, it is difficult to utilize integrated data and it is only used sparingly. Creating and sharing a unique key that can identify a construction site will enable integrated accumulation and management of construction-related data for various purposes. At this point, it is most efficient to assign a unique key based on KISCON. KISCOn data conforms to the construction site definition and covers most of the public, private, architectural and civil works. In addition, there is an advantage in that DB construction is performed in the construction situation, which is a relatively preceding process. In the future, it is necessary to create a practical construction site integrated DB through the production of an integrated key table containing linkage information of unique keys for site management, performance indicators, and statistics production.

Although the construction industry has become highly advanced, traditional accidents still occur on construction sites, prompting numerous studies and systems aimed at accident prevention using smart construction technology. This study is an exploratory investigation of utilizing unmanned aerial vehicles (UAVs) for safety management. The study aims to verify harmful and hazardous factors that UAVs can detect on construction sites, classify management factors, and define improvement measures to present a checklist for each process. Through this, we hope that smart construction technology will be further expanded and applied for on-site safety management.

If the participants in construction site safety management perform their duties in accordance with the provisions of the Industrial Safety and Health Act, the burden on safety managers would be minimal. However, the lack of specific work guidelines for each participating entity and the greater responsibility of the safety and health general manager than the management supervisor have resulted in safety managers' workload being increased due to the problem of management supervisors' neglect of safety management. In this study, we conducted a survey of the safety manager's duties and related documents during the construction project initiation, early stages, ongoing work, and disaster occurrence/investigation, and conducted interviews to improve and enhance the division of duties.

Modular construction is a cost-effective and time-saving method of building that involves prefabricating modules in a factory and assembling them on-site. However, effective management factors must be considered at each stage of the process to ensure quality and stability. This study analyzes these management factors and proposes systematic ways to manage them, including construction planning, data management, and quality assurance. Proper management can improve construction quality, shorten construction time, and reduce costs. These stage-specific management factors are crucial for the success of modular construction projects, and further research and efforts are needed to promote its widespread use in the construction market.

In this study, the legal and institutional status of construction supervising and construction inspector was identified. As a result of examining the definitions of construction supervision terms, focusing on domestic construction-related laws, it was found that there were no consistency between each laws regarding 'terminology' and 'definitions'. In addition, the scope of construction inspector's work continues to expand through the delegation provisions to lower statutes, however, responsibility, authority, and inspection cost are not taken into account properly. In addition in order to introduce digital technology to the smart construction site, which is currently active under way, it is judged that the law and institutional contents need to be improved further.

This study examined the effect of curing conditions on the compressive strength of dry mortar for floor. The compressive strength according to the relative humidity during curing was compared, and the influence of expansive additives on compressive strength under water curing was reviewed. As a result, low relative humidity conditions during curing was not effective in improving the compressive strength of dry mortar for floor, and it was judged that the continuous hydration reaction insufficient due to lack of the moisture supply. In order to improve compressive strength, high relative humidity maintenance was found to be an important factor. However, under water curing conditions, the compressive strength has decreased as a result of continuous volume expansion due to the use of the expansive additives.

The Post-Construction Evaluation and Management System has been operated over the past 20 years not only to analyze the performance of large-scale construction projects, and but also to provide useful reference data for future similar projects. Although the Post-Construction Evaluation and Management Center has been legally designated and operated since 2020, various problems have been occurring in the operation of the system. Accordingly, this study proposes strategies for facilitating Post-Construction Evaluation and Management System in terms of the following three aspects: (1) improving the implementation rate of post-construction evaluation; (2) improving the information management system related to post-construction evaluation; (3) improving the utilization of post-construction evaluation outcomes. Based on the results of this study, a specific action plan will be prepared, which is expected to contribute to the efficiency of construction project performance management in the future.

Frequent accidents occur when workers at construction sites leave the safety zone, and particularly in the past 5 years, 9 fatal accidents occurred at the Korea Railroad Corporation due to train accidents on other tracks during track work. With the Severe Accident Punishment Act taking effect in January 2022, it is a priority to secure a safe work environment for workers at industrial (construction) sites. Therefore, there is a need to manage workers' departure from the safety zone (construction zone) and to facilitate communication within the construction zone. In this study, a mobile edge computing CCTV system is proposed that uses geofencing to determine whether workers are working in the danger zone, which can judge and respond in real-time to the ever-changing field environment. The proposed system is mobile and flexible, rather than server-based fixed CCTV. However, since it is designed mainly based on images, it has limitations in recognition rate depending on the environment such as distance, viewing angle, and illumination. As a way to compensate for this, it is required to develop more reliable equipment by combining technologies such as LiDAR and Radar.

Using the CSI(Construction Safety Management Integrated Information) data, a comparative analysis was conducted by work type and construction cost according to whether the construction sites were subject to making a safety management plan or not. As a result, by type of work, the ratio of deaths in non-plan sites was high in mechanical facilities and earthworks, and the operation performance of the system was much higher in sites that were less than 5 billion won of construction cost.

In this application study, field pilot tests were performed to evaluate the validity of a proposed formula between the exerted electrical energy and SPT N-value based on the result of the basic study. Measurement sensors and recording system were developed to obtain exerted motor current and drilling depth in a field. By using the correlation formula proposed in the basic study, the measured motor current and boring speed were applied to predict SPT N-value and the predicted N-values were compared to SPT N-value of site exploration. From the comparisons it is verified that the exerted electrical energy to bore ground might be used to predict SPT N-value and pile tip location.

PHC pile head cutting is an essential work in pile foundation construction. However, since the work has labor-intensive characteristics, there are problems such as productivity and safety. So in previous study PHC pile one-cutting head cutting automation equipment was developed to solve this problem. However, it has been investigated as a limitation that checking the cutting position of the PHC pile can be challenging in place where a rotary laser leveler cannot irradiate cutting position, as the sensing unit of the developed automated equipment utilizes an optical method. Therefore, the objective of this study is to delvelop a GNSS-based methodology for sensing the cutting position of PHC piles to overcome the limitations of the optical method and to examine its feasibility for field application. If the proposed methodology is applied to the construction site, it is expected that the convenience and productivity of the PHC pile cutting position sensing work will be improved.

To improve the cost performance of construction sites, various systems and standards are constantly being developed and implemented. Although legal requirements for these system and standard improvements have been increasing, the cost efficiency performance of construction sites remains stagnant. We have digitized documents generated through construction supervision work at 39 building construction sites and proposed a model that can support decision-making in cost efficiency evaluation. This model selects key keywords that are considered to be highly related to cost efficiency by identifying the patterns and relationships of keywords through associated rule analysis and social network analysis using keywords derived from documents. In addition, it is expected to be used as a decision-making aid to determine the cost efficiency of a specific building construction site by establishing a logistic regression model using core keywords. As a systematic database of construction supervision documents and an integrated system of massive data generated by digital technology are established in the future, the accuracy and reliability of the cost efficiency evaluation model are expected to be reinforced.

This paper provides an overview of seismic design considerations for vertical construction joints of a slurry walls used as a permanent basement walls.

The current building structural standards present design requirements for the vertical construction joint of a slurry wall when it is used as a permanent wall. This paper proposes design methods and considerations according to the requirements of the relevant standards.

To design the shear connections for vertical construction joints of slurry walls, it is necessary to create a force-displacement curve that represents the structural performance of the shear connections. This paper proposes a method for preparing the force-displacement curve of the shear connections including major considerations.

Current building structural standards require the shear strength and rigidity in the design of vertical construction joints in a slurry wall. This paper proposes a shear key resistance method for shear connection of vertical construction joints, and compares its structural performance with the currently prevalent method of shear friction rebar. The study found the structural performance of the shear key resistance method was significantly better than that of the shear friction rebar method.

The shear connection of the vertical construction joint of a slurry wall by the concrete shear key has excellent structural performance and is economical and eco-friendly. However, technology for forming concrete shear keys in the underground is still underdeveloped. This paper proposes the development of the construction technology required to form a concrete shear key at the vertical construction joint of the slurry wall.

In an era where everything is digitalized using AI(Artificial Intelligence), such as the ChatGPT craze, the evacuation guidance system still uses an analog and fixed method, so there is a limit to quick response in case of fire. In order to overcome this, we introduce a digitally transformed evacuation guidance system using AI and discuss its effectiveness.

In the era of AI, intelligent construction safety technologies are being introduced to the construction safety environment, but the application of AI has limitations due to the lack of accident images to learn in complex construction sites. In order to overcome this, we will introduce an intelligent risk detection system that dramatically improves risk detection accuracy by combining AI with digital twin technology, and introduce various cases.

This article proposes a method to assess construction safety risk during the construction phase based on accident loss costs. Risk assessments for hazardous construction work are required by law, but they lack quantitative criteria. To address this, a survey estimated loss costs due to fatalities in the construction industry, finding labor loss cost and delay reimbursement cost to be the largest factors. The proposed method uses algorithm to calculate expected accidents and risk levels based on project characteristics, work methods, personnel, and environment data. This method is expected to enhance the reliability and usability of risk assessments during the construction phase of construction projects.

In this study, the compressive strength and ultrasonic pulse velocity were evaluated according to the elapsed time on concrete mixed with normal and lightweight aggregates at early age. For evaluation in various strength ranges, the design compressive strength was set to 30, 45, and 60MPa and evaluated. As a result of the experiment, the compressive strength of concrete mixed with lightweight aggregates developed 5MPa earlier compared to normal aggregate concrete, and the UPV showed a similar tendency.

The purpose of this research and development is to develop a structure module that improves the efficiency and constructability of the layout structure as well as the design development of rainwater permeable storage tank blocks using inorganic binders and aggregates with the aim of reducing greenhouse gas (CO₂) with eco-friendly materials. In addition, for the efficient response to flooding of the developed permeable storage structure, we present a technical solution for combining drone mapping technology and flood monitoring technology that can analyze topographical factors in detail.