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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Recycled Construction Resources Institute
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Journal DOI :
Korean Recycled Construction Resource Institute
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Volume & Issues
Volume 3, Issue 4 - Dec 2015
Volume 3, Issue 3 - Sep 2015
Volume 3, Issue 2 - Jun 2015
Volume 3, Issue 1 - Mar 2015
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Compressive Strength Properties of Steam-cured High Volume GGBFS Cement Concrete
Hong, Seong-Hyun ; Kim, Hyung-Suk ; Choi, Seul-Woo ; Lee, Kwang-Myong ; Choi, Se-Jin ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 1~6
DOI : 10.14190/JRCR.2015.3.1.001
Recently, lots of researches on concrete with high volume mineral admixture such as ground granulated blast furnace slag (GGBFS) have been carried out to reduce
. It is known that the precast concrete has an advantage of high strength at early age due to steam curing, even if concrete has high replacement level of mineral admixture. However it demands the investigation of compressive strength properties according to steam curing regimens. In this study, concretes with water-binder ratio of 32, 35% and water content of 135, 150,
were produced to investigate compressive strength properties of high volume (60% by mass) GGBFS cement concrete according to steam curing regimens. Then steam curing was implemented with the maximum temperature of 50,
and steaming time of 5, 6, 7 hours. From the test results, it was found that steam curing was effective to raise early strength of high volume GGBFS cement concrete, but 28 day compressive strengths of steam cured specimens were lower than those of water cured specimens. Thus, a further study would be needed for the optimum steam curing regimens to satisfy target demolded strength and specified strength for the application of high volume GGBFS cement concrete to precast concrete members.
Shape Improvement and Optimum Gradation of Dry Processed Bottom Ash for Lightweight Mortar
Choi, Hong-Beom ; Kim, Jin-Man ; Sun, Jung-Soo ; Han, Dong-Yeop ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 7~14
DOI : 10.14190/JRCR.2015.3.1.007
The aim of this research is suggesting dry processed bottom ash as a new and economical source of lightweight aggregate for mortar and concrete. The dry process of bottom ash is an advance method of water-free and no chloride because only cooled down by double dry conveyer belt systems. Furthermore, because of relatively slow cooling down process helps burning up the remaining carbon in bottom ash. Using this dry process bottom ash, to evaluate the feasibility of using as a lightweight aggregate for mortar and concrete, two-phase of experiments were conducted: 1) improving shape of the bottom ash, and 2) controlling grade of the bottom ash. From the first phase of experiment, additional abrasing process was conducted for round shape bottom ash, hence improved workability and compressive strength was achieved while unit weight was increased comparatively. Based on the better shape of bottom ash, from the second phase, various grades were adopted on cement mortar, standard grade showed the most favorable results on fresh and hardened properties. It is considered that the results of this research contribute on widening sustainable method of using bottom ash based on the dry process and increasing value of bottom ash as a lightweight aggregate for concrete.
Analysis of Fundamental Properties of Concrete Using Mix of Coarse Aggregate With Formation Causes
Noh, Sang-Kyun ; Kim, Young-Hee ; Kim, Jeong-Bin ; Han, Cheon-Goo ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 15~21
DOI : 10.14190/JRCR.2015.3.1.015
Recently, attempts of replacing some of natural aggregate with mix of low quality aggregate are carried out for stable supply of aggregate. However, low quality aggregate such as recycled aggregate produced during the disposal process of construction wastes and by-product aggregate produced by industrial activities has problem of failing to comply to KS Standards. Therefore, we have compared fundamental properties of concrete by using granite crushed aggregate, recycled aggregate, blast furnace and electric arc furnace slag aggregate for effective utilization of lacking aggregate resources. As the result, slump in case of mixed use of aggregate was increased 0~10% compared to single use. Therefore, it is judged to be economically advantageous as it can expect effects in unit quantity or reduction of SP agent. Compressive strength in case of mixed use of aggregate was increased 0~10% compared to single use as it filled internal crevice of concrete with continuous particle size distribution. Accordingly, if we utilize by satisfying standard particle scope through mix of aggregate with different cause of formation in proper ratio, it was possible to confirm utility of mixed aggregate with demonstration of effects of increases of fluidity and compressive strength of concrete.
Probability-Based Durability Design for Concrete Structure with Crack: Bimodal Distribution of Chloride Diffusion
Na, Ung-Jin ; Kwon, Seung-Jun ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 22~33
DOI : 10.14190/JRCR.2015.3.1.022
Chloride ions in RC (Reinforced Concrete) structures can cause very severe corrosion in reinforcement steel. It is generally informed that chloride penetration can be considerably accelerated by enlarged chloride diffusion due to cracks. These cracks play a role in main routes through which chloride ions penetrate into the concrete, and also lead to steel corrosion in RC structures exposed to chloride attack, such as port and ocean structures. In this paper, field survey including evaluation of crack and chloride concentration distribution in concrete is performed to investigate an effect of crack on chloride diffusion. The service life of cracked concrete exposed to the marine environmental condition is estimated considering the crack effect on chloride diffusion. For this purpose, diffusion coefficients in cracked concrete are obtained based on the field survey. Using the relationship between diffusion coefficients in the cracked concrete and the crack widths, service life of the cracked concrete is predicted in a probabilistic framework. A bimodal distribution with two peaks, consisting of a weighted sum of two normal distributions is introduced to describe chloride diffusion of the concrete wharf with crack.
Study on the Physical Properties of the Artificial Lightweight Aggregate Recycled from the Dyestuff Sludge Treated Chemically With Ti and Fe Salt
Choi, Jong-Oh ; Jung, Yong-Wook ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 34~42
DOI : 10.14190/JRCR.2015.3.1.034
The paper investigates environmental hazards and characteristics of the artificial lightweight aggregate manufactured by using dyestuff sludge from dyeing industrial complex. The dyestuff sludge used in this study is chemically treated with Ti and Fe salt for the purpose of recycling. The artificial lightweight aggregate is manufactured through 3 step; 1) Selecting the optimum moisture content by evaluating plasticity from the mixing ratio of the clay and sludge, 2) shaping round type based on the optimum mixing ratio, 3) drying and Sintering process. Based on KS F 2534 "Lightweight Aggregate for Structural concrete", the particle size, fineness modulus, the density, absorption, unit volume weight, stability and environmental hazards of the manufactured lightweight aggregate are evaluated. Experimental results show that the particle size and fineness modulus is out of the range. However, it is observed that other physical properties are within criteria. In addition, it is confirmed that the problem of the particle size and fineness modulus could be solved in the manufacturing process.
Effect of the Replacement of Recycled Coarse Aggregates Under 13mm on Engineering Properties of the Concrete
Han, Min-Cheol ; Kang, Byeong-Heo ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 43~49
DOI : 10.14190/JRCR.2015.3.1.043
The objective of this paper is to investigate experimentally the effect of the substitution of recycled aggregates under 13mm on the properties of the concrete using coarse aggregate with size of 13~25mm. Recycled aggregate under 13mm were substituted to the concrete ranged from 10% to 100%. To compare the properties with the case of recycled aggregate, crushed stone with smaller than 13mm was also substituted to the concrete by 20% and 40%. Test results showed that increase of recycled aggregate under 13mm resulted in the increase of slump and compressive strength compared with plain mixture, which was made with only aggregate with 13~25mm size. This is due to the dense gradation of aggregate in association with addition of relatively small particle. It is thought that the use of recycled aggregate under 13mm along with 30% contributes to the quality improvement of the concrete made with only 13~25mm aggregate.
Basic Properties of Alkali-activated Mortar With Additive`s Ratio and Type of Superplasticizer
Han, Cheon-Goo ; Chang, Ji-Han ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 50~57
DOI : 10.14190/JRCR.2015.3.1.050
Portland cement production is under critical review due to high amount of
gas released to the atmosphere. Attempts to increase the utilization of a by-products such as fly ash and ground granulated blast-furnace slag to partially replace the cement in concrete are gathering momentum. Many researchs on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of
gas. In this study, we investigated the influence of the fluidity, air content and compressive strength of mortar on alkaline activator in order to develop cementless fly ash and ground granulated blast-furnace slag based alkali-activated mortar with superplasticizer. In view of the results, we found out that Pn of fluidity and compressive strength is the best in four type of superplasticizer, and PNS of powder type of fluidity is better than that of liquid type in the case of AA.
Shear Behavior of RC Beams Using Alkali Activated Slag Concrete
Choi, Sung ; Lee, Kwang-Myong ; Yoo, Sung-Won ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 58~63
DOI : 10.14190/JRCR.2015.3.1.058
Several researches on cement zero concrete using alkali-activators have been conducted to investigate its fundamental material properties such as slump, strength and durability, however, research on the structural behavior of relevant members involving the elastic modulus, stress-strain relationship is essential for the application of this cement zero concrete to structural members. In this paper the shear behavior of reinforced concrete beams using 50 MPa-alkali activated slag concrete was experimentally evaluated. To achieve such a goal, six reinforced concrete beam specimens were fabricated and their shear behaviors were observed. The maximum difference between test results and analysis results in crack shear stress for beam specimens without stirrups is 31%, while that for beam specimens with stirrup is 15%. Furthermore, it is also found that the shear strength of alkali activated slag concrete is by 22~57% greater than the nominal shear strength calculated by design code, implying that shear design equations would provide conservative results on the safety side.
A Study on Economically-Efficient Binder Combination of 80MPa Ultra High Strength Concrete
Park, Chun-Jin ; Koh, Kyung-Teak ; Ryu, Gum-Sung ; Ahn, Gi-Hong ; Ahn, Sang-Ku ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 64~71
DOI : 10.14190/JRCR.2015.3.1.064
Silica fume is generally adopted as admixture for Ultra High Strength Concrete (UHSC) owing to its remarkable contribution to the strength and durability but increases significantly the fabrication cost of UHSC. Accordingly, this study investigates the replacement of silica fume by blast furnace slag (BS) and fly ash (FA) in order to lower the fabrication cost of 80MPa-UHSC. To that goal, experiment is conducted on the mix proportions of mortar in terms of its binder combination, water-to-binder ratio (W/B) and unit binder content. Based on the experimental data, a mix design of concrete is derived and its properties are verified. The results reveal that a W/B of 21% and unit binder content of
are appropriate to achieve 80MPa-UHSC using a binder composed of 60% of OPC, 30% of BS and 10% of FA. The properties of the corresponding UHSC are seen to be satisfactory with a slump flow of 715mm and compressive strength of 97MPa at 28days. The application of the binder combination derived in this study is analyzed to reduce the cost by 50% of binder compared to the mix using silica fume while realizing equivalent performance.
Assessment on Applicability of Recycled Aggregates for Backfill Materials of Underground Transmission Lines Based on Field Demonstration Tests
Kang, Sung-Chur ; Lee, Kang-Ryel ; Ahn, Tae-Bong ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 72~83
DOI : 10.14190/JRCR.2015.3.1.072
Underground transmission lines always generate heat and transmit heat through surrounding backfill materials. Therefore, in the design of power lines it becomes a very crucial factor to transfer heat effectively into the neighbouring soils. In this study, in order to enhance field applicability of recycled aggregates for backfill material of transmission lines, quality criteria and construction criteria were proposed, and thermal stability of power lines through field demonstration tests were analyzed. In the field tests, two types of recycled aggregates and sand which is currently used for backfilling were compared in terms of thermal behaviour. Test results showed that recycled aggregates represented similar trends with sand in temperature and moisture content corresponding to time lapse and distance from the heat source. Consequently, recycled aggregates can be utilized for backfill materials of underground transmission lines as a substitute material of sands.
Engineering Property of Basalt Fiber as a Reinforcing Fiber
Choi, Jeong-Il ; Jang, Yu-Hyun ; Lee, Jae-Won ; Lee, Bang-Yeon ;
Journal of the Korean Recycled Construction Resources Institute, volume 3, issue 1, 2015, Pages 84~89
DOI : 10.14190/JRCR.2015.3.1.084
Basalt fiber has many advantages as a reinforcing fiber such as high tensile strength and similar density to concrete. This study investigated the bonding property and the effect of fiber orientation on tensile strength of basalt fiber. Single fiber pullout tests for basalt and polyvinyl alcohol (PVA) fibers were performed to evaluate the bonding property between basalt fiber and mortar. And then tensile strength of basalt, PVA, and polyethylene (PE) fibers according to fiber orientation were measured. From the test results, it was exhibited that the chemical bond, frictional bond, and slip-hardening coefficient of basalt fiber were 1.88, 1.03, 0.24 times of PVA fibers, respectively. And the strength reduction coefficient of basalt fiber was 9 times of PVA fiber and 3 times of PE fiber.