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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korea Institute of Building Construction
Journal Basic Information
Journal DOI :
The Korean Institute of Building Construction
Editor in Chief :
Volume & Issues
Volume 12, Issue 6 - Dec 2012
Volume 12, Issue 5 - Oct 2012
Volume 12, Issue 4 - Aug 2012
Volume 12, Issue 3 - Jun 2012
Volume 12, Issue 2 - Apr 2012
Volume 12, Issue 1 - Feb 2012
Selecting the target year
Hydration Analysis of Fine Particle and Old Mortar Attached on the Surface of Recycled Aggregate
Ko, Dong-Woo ; Choi, Hee-Bok ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 460~467
DOI : 10.5345/JKIBC.2012.12.5.460
When recycled aggregate with old mortar and particles is used in concrete mixing, such aggregates can affect hydration reaction by promoting or inhibiting it. In this study, the possibility of hydration reaction on old mortar and particle was analyzed. Hydration reaction was carried out in old mortar that is finely crushed by an impact machine in the production of recycled aggregates, and it was found that this did have an impact on the strength development of concrete. Unlike in old cement, the hydration reaction did not progress in the particles, and it had high amounts of silica powder and calcium carbonate. In conclusion, the old mortar can have the influence of improving compressive strength, but the particles can delay the setting time of recycled aggregate concrete.
Bond Strength of Mortar mixed Activated Hwangtoh
Go, Seong-Seok ; Yeo, Sang-Ku ; Lee, Hyun-Chul ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 468~477
DOI : 10.5345/JKIBC.2012.12.5.468
This study aimed to mix and test mortar incorporating activated Hwangtoh to improve the Hwangtoh brick bond strength of brick structures. To do this, the bond strength correlation of mortar was analyzed by means of materials and experiment factors and levels, and the optimum conditions were suggested after analyzing the physical properties of brick and the mix ratio of mortar and additive. Furthermore, the compressive strength and bond strength were found to be in inverse proportion, and in terms of the materials and mixing level, W/C ratio, substitution ratio of activated Hwangtoh, and fine aggregate grading were shown to have a considerable influence on the strength. In conclusion, the optimum mixing conditions to improve the bond strength are found to set W/C ratio at 65% and replacmenet ratio of activated Hwangtoh at 10%.
Radiation Shielding Property of Concrete Using the Rapidly Cooled Steel Slag from Oxidizing Process in the Converter Furnace as Fine Aggregate
Kim, Jin-Man ; Cho, Sung-Hyun ; Kwak, Eun-Gu ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 478~489
DOI : 10.5345/JKIBC.2012.12.5.478
Each year, about four million tons of steel slag, a by-product produced during the manufacture of steel by refining pig iron in the converter furnace, is generated. It is difficult to recycle this steel slag as aggregate for concrete because the reaction with water and free-CaO in steel slag results in a volume expansion that leads to cracking. However, the steel slag used in this study is atomized using an air-jet method, which rapidly changes the melting substance at high temperature into a solid at a room temperature and prevents free-CaO from being generated in steel slag. This rapidly-cooled steel slag has a spherical shape and is even heavier than natural aggregate, making it suitable for the aggregate of radiation shielding concrete. This study deals with the radiation shielding property of concrete that uses the rapidly-cooled steel slag from the oxidizing process in the converter furnace as fine aggregate. It was shown that the radiation shielding performance of concrete mixed with rapidly-cooled steel slag is even more superior than that of ordinary concrete.
Quality of Recycled Fine Aggregate using Neutral Reaction with Sulfuric Acid and Low Speed Wet Abrader
Kim, Ha-Seog ; Lee, Kyung-Hyun ; Kim, Jin-Man ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 490~502
DOI : 10.5345/JKIBC.2012.12.5.490
The use of recycled aggregate, even for low-performance concrete, has been very limited because recycled aggregate, which contains a large amount of old mortar, is very low in quality. To produce a high-quality recycled aggregate, removing the paste that adheres to the recycled aggregate is very important. We have conducted research on a complex abrasion method, which removes the component of cement paste from recycled fine aggregate by using both a low-speed wet abrasion crusher as a mechanical process and neutralization as chemical processes, and well as research on the optimal manufacturing condition of recycled fine aggregates. Subsequently, we evaluated the quality of recycled fine aggregate manufactured using these methods, and tested the specimen made by this aggregate. As a result, it was found that recycled fine aggregates produced by considering the aforementioned optimal abrasion condition with the use of sulfuric acid as reactant showed excellent quality, recording a dry density of 2.4 and an absorption ratio of 2.94. Furthermore, it was discovered that gypsum, which is a reaction product occurring in the process, did not significantly affect the quality of aggregates. Furthermore, the test of mortar using this aggregate, when gypsum was included as a reaction product, showed no obvious retarding effect. However, the test sample containing gypsum recorded a long-term strength of 25.7MPa, whereas the test sample that did not contain gypsum posted a long-term strength of 29.4MPa. Thus, it is thought to be necessary to conduct additional research into the soundness and durability because it showed a clear reduction of strength.
Characteristics of Alkali-activated Natural Hwangtoh Paste Utilizing Microwave Heating
Kim, Baek-Joong ; Yi, Chong-Ku ; Kang, Kyung-In ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 503~509
DOI : 10.5345/JKIBC.2012.12.5.503
In this study, the potential use of indigenous natural loess(Hwangtoh) as a new construction material, via alkali activation in conjunction with microwave heating, was investigated. Hwangtoh pastes with three different mix proportions of varying alkali liquid concentrations at a constant liquid-to-Hwangtoh ratio of 0.55 were prepared. Through the investigation it was found that it is possible to prepare Hwangtoh paste with
at the age of 4 hours with the alkali solution of 8M NaOH and 1:4.5 mass ratio of liquefied
at the curing temperature of
by microwave heating. The strength development at early age of the alkali activated Hwangtoh paste specimens may be attributed to both a higher rate of reaction and moisture evaporation due to microwave heating.
Recycling of In-site waste soil material to fill a hollow between PHC pile and Earthen wall
Jang, Myung-Houn ; Choi, Hee-Bok ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 510~517
DOI : 10.5345/JKIBC.2012.12.5.510
This study evaluated the recycling potential of in-site waste soil as pile back filling material (PBFM). We performed experiments to check workability, segregation resistance, bond strength, direct shear stress test, and dynamic load test using in-site waste soil in coastal areas. We found that PBFM showed better performance than general cement paste in terms of workability, segregation resistance, and bond strength. On the other hand, the structural performance of PBFM was slightly lower than that of general cement paste due to the skin friction force of pile by Pile Driving Analyzer and direct shear stress. However, because this type of performance degradation in terms of structure can be improved through the use of piles with larger diameter or by changing the type of pile, considering the economics and environment, we considered that recycling of PBFM has sufficient value.
Knowledge-Based Model for Forecasting Percentage Progress Costs
Kim, Sang-Yong ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 518~527
DOI : 10.5345/JKIBC.2012.12.5.518
This study uses a hybrid estimation tool for effective cost data management of building projects, and develops a realistic cost estimation model. The method makes use of newly available information as the project progresses, and project cost and percentage progress are analyzed and used as inputs for the developed system. For model development, case-based reasoning (CBR) is proposed, as it enables complex nonlinear mapping. This study also investigates analytic hierarchy process (AHP) for weight generation and applies them to a real project case. Real case studies are used to demonstrate and validate the benefits of the proposed approach. By using this method, an evaluation of actual project performance can be developed that appropriately considers the natural variability of construction costs.
Life Cycle Cost Breakdown Structure Development of Buildings through Delphi Analysis
Jeong, Jae-Hyuk ; Shin, Han-Woo ; Ryu, Han-Guk ; Kim, Gwang-Hee ; Kim, Tae-Hui ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 528~538
DOI : 10.5345/JKIBC.2012.12.5.528
With domestic construction projects becoming bigger, more specialized and more advanced, the construction industry is striving to improve quality and quantity, and is diversifying functions and shapes. Nevertheless, the process of a construction project causes problems when we estimate construction price, because the cost breakdown structures are different in each step. The primary aim of this study was to estimate building life cycle cost using the Delphi method. The cost breakdown structure for life cycle cost was classified into planning, design, construction, maintenance and waste disposal, and each detailed classification was determined by estimating life cycle cost. Moreover, the developed cost breakdown structure is verified by consulting with experts to secure objectivity and validity.
Compressive Shear and Bending Performance of Compressed Laminated Wood after Microwave Heating
Park, Cheul-Woo ; Lim, Nam-Gi ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 539~547
DOI : 10.5345/JKIBC.2012.12.5.539
To manufacture laminated wood with improved mechanical properties by providing uniform adhesiveness, the adhesive was applied and the plate adhesive was laminated on the wood surface. Then, after laminating the wood on the top part of the adhesivebond, it was heated and dried while the adhesive was stiffened using microwaves, and the test piece was manufactured by compressing it with the press machine for thirty minutes. The temperature and the water content were examined according to the heating time of the wood heated with the microwave, and testing was conducted on the shear strength and flexural strength of the wood. In addition, the microstructure of the adhesive bond between the wood was recorded to confirm the penetrabilityinto the wood structure for the adhesive. After the test was conducted, it was found that the test piece manufactured with wood that has its water content leveled with the microwave heating showed improved shear strength and bending strength compared to the standard test piece. With regard to adhesives, liquefied polyvinyl acetate resin and plate`s PVB resin were found to have superior adhesive strength. Also, after filming the cellular microstructure, it was found that when the laminated wood is heated with microwaves, the infiltration of the adhesive into the inside of the wood becomes easy, which makes it effective for improving adhesiveness.
An Experimental Study on the Thermal Performance of Cement Mortar with Granulated PCM
Jeong, You-Gun ; Park, Ki-Bong ; Lee, Han-Seung ;
Journal of the Korea Institute of Building Construction, volume 12, issue 5, 2012, Pages 548~557
DOI : 10.5345/JKIBC.2012.12.5.548
In this study the thermal performance of G-PCM replaced for find aggregate in mortar specimens was evaluated using TG-DTA. As a result, it was found that when solid changed into liquid, it absorbed heat, and when liquid changed into solid, it radiated heat. In addition, the fluidity and the compressive strength of mortar with G-PCM can be applied to the floor mortar and a wall finish material. Also the higher the replacement ratio, the larger the latent heat capacity. It was found that the mortar with G-PCM slowed the increase and decrease of temperature. Thus, the duration of pleasant indoor temperature is extended by the floor and wall mortar with G-PCM. In conclusion, G-PCM is expected to reduce the heating energy consumption.