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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Recycled Construction Resources Institute
Journal Basic Information
Journal DOI :
Korean Recycled Construction Resource Institute
Editor in Chief :
Volume & Issues
Volume 2, Issue 4 - Dec 2014
Volume 2, Issue 3 - Sep 2014
Volume 2, Issue 2 - Jun 2014
Volume 2, Issue 1 - Mar 2014
Selecting the target year
Evaluation of Reinforced Concrete Column Exposed to Chloride Attack Considering Repair Timing
Kim, Seong-Jun ; Kim, Young-Joon ; Kwon, Seung-Jun ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 1~9
DOI : 10.14190/JRCR.2014.2.1.001
In this paper,
amount is evaluated considering repairing timing and unit
amount per repair method including various stage of material manufacturing, moving, and construction. Four mix proportions with mineral admixture are considered and repairing timing/numbers are simulated based on the results from Life 365 which can handle chloride penetration. Furthermore two repair methods (simple cover concrete replacement and replacement with electro-chemical method for removing chloride content) are considered and the related
emissions are evaluated. From the study, the case with high W/B (water to binder ratio) ratio shows smaller
emission in construction stage but it increases more rapidly with increasing number of repair.
emission considering electro-chemical method greatly increases with the increasing unit
for the repairing method. The numbers of jumping step (repairing number) are evaluated to be 9 for WB37-OPC, 18 for WB50-OPC, 4 for WB40-SG, and 7 for WB47-SG respectively. RC structures with the longer maintenance free period are evaluated to be advantageous for saving
Fundamental Evaluation and Hydration Heat Analysis of Low Heat Concrete with Premixed Cement
Yoon, Ji-Hyun ; Jeon, Joong-Kyu ; Jeon, Chan-Ki ; Kim, Ki-Hyung ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 10~18
DOI : 10.14190/JRCR.2014.2.1.010
This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.
A Study on the Mechanical Properties of Fiber Reinforced Concrete by Kenaf Dosages
Kwon, Yeong-Ho ; Jun, Woo-Chul ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 19~25
DOI : 10.14190/JRCR.2014.2.1.019
The purpose of this study is to establish experimentally the mechanical properties of fiber reinforced concrete using kenaf dosages and propose the usable method of kenaf fiber in the concrete industry as natural fiber materials. Kenaf fiber help make the concrete strength including tensile and flexural stronger, more resistant to plastic and drying shrinkage, less amount of carbon dioxide because of having a rough surface and excellent tensile strength of fiber and improving the concrete's corrosion resistance. It is to select the kenaf dosages of 4 cases (0, 0.3, 0.6 and
and perform various tests including slump, air content, plastic and drying shrinkage, flexural and tensile strength for fiber reinforced concrete. The results of this study are as follows : In case of increasing kenaf fiber dosages, show the slump decrease and air content increase, also take effect results for increasing concrete strength including flexural and tensile, decreasing plastic and drying shrinkage. therefore, considered test results and cost, the optimum dosages of kenaf fiber is proposed about
and need to study on the site application considering concrete quality and another compared tests.
Effects of Mineral Admixture on the Characteristics of Grout for PSC Bridge
Koh, Kyung-Taek ; Ryu, Gum-Sung ; Ahn, Ki-Hong ; Kang, Su-Tae ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 26~33
DOI : 10.14190/JRCR.2014.2.1.026
The study investigates the effects of the type, replacement ratio and method of use of mineral admixtures on the fluidity, bleeding ratio, volumetric change and compressive strength of the grout in order to provide basic data for the development of high-quality grout for PSC bridges. In view of the results relative to the type and replacement ratio of the mineral admixtures, it appears that fly ash has practically no effect on the improvement of the fluidity nor on the reduction of bleeding and shrinkage of the grout. On the contrary, blast furnace slag and silica fume appear to have significant effect on the improvement of the fluidity or on the reduction of bleeding and shrinkage of the grout. With regard to the combined use of mineral admixtures, the combination of fly ash and blast furnace slag provides satisfactory fluidity but with significant increase of bleeding and shrinkage, whereas the combination of blast furnace slag and silica fume reduces bleeding and shrinkage but with large loss of the fluidity. On the other hand, the combination of fly ash and silica fume results in satisfactory fluidity accompanied with fair reduction of bleeding and shrinkage of the grout. In view of these results, the type, replacement ratio and method of use of the mineral admixtures are seen to influence the fluidity, bleeding and volumetric change of the grout. Accordingly, it is necessary to select the mineral admixtures considering these effects for their exploitation in the grout of PSC bridges.
Characteristics for Reinforcement Corrosion and Chloride Ion Diffusion of High Volume Fly Ash Concrete
Kwon, Soon-Oh ; Bae, Su-Ho ; Lee, Hyun-Jin ; Jung, Sang-Hwa ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 34~39
DOI : 10.14190/JRCR.2014.2.1.034
The purpose of this experimental research is to evaluate the resistance of reinforcement corrosion and chloride ion penetration of high volume fly ash (HVFA) concrete. For this purpose, concrete test specimens were made for various strength level and replacement ratio of fly ash, and then compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91 and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that compressive strength of HVFA concrete was decreased with increasing replacement ratio of fly ash but long-term resistance against reinforcement corrosion and chloride ion penetration of that was increased.
A Characteristics of Fly-ash Concrete Incorporating Tablet-shaped Accelerators in Cold Weather
Lee, Yong-Soo ; Ryou, Jae-Suk ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 40~45
DOI : 10.14190/JRCR.2014.2.1.040
Although the accelerators are used at the early stage to control setting-time and strength of concrete when cold-weather concrete is utilized, no security of workability occurs because the early hydration makes them react rapidly. Therefore, the tablet used in previous study is applied in this study. In particular, because a small amount of fly-ash being replaced in cold weather concrete of domestic, fly-ash concrete incorporating the tablet is discussed in workability by elapsed time, early strength to ensure the development of adequate strength, and freezing-thawing resistance. As a result, both 0.5 and 1.0% tablets were found to be superior. Thus, it was verified in cold weather concrete incorporating fly-ash that workability can be secured, as well as the development of early strength to prevent early frost.
The Properties of Strength Development of High Volume Fly Ash Concrete with Reduction of Unit Water Content
Choi, Yun-Wang ; Park, Man-Seok ; Choi, Byung-Keol ; Oh, Sung-Rok ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 46~51
DOI : 10.14190/JRCR.2014.2.1.046
In this study, strength development properties of high volume fly ash concrete was evaluated through compressive strength of concrete with reduction of unit water content. And concrete specimens were prepared according to target strength 3 level and variation of unit water content. As a result, the improved fluidity were obtained as a result of the ball bearing action of the spherical, the electrostatic repulsion and the particle size distribution of fly ash particles in case of using more than 50% fly ash. Through this, the mixture of fly ash has been shown to reduce the amount of water required in concrete. Also, the early strength of high volume fly ash concrete with reduction of unit water content was improved more about 66% than general concrete mixture.
Study on Mechanical Properties of Geopolymer Concrete using Industrial By-Products
Kim, Si-Hwan ; Koh, Kyung-Taek ; Lee, Jang-Hwa ; Ryu, Gum-Sung ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 52~59
DOI : 10.14190/JRCR.2014.2.1.052
This study examines the compressive strength, elastic modulus and splitting tensile strength of geopolymer concrete in order to evaluate its mechanical characteristics according to the admixing of fly ash and blast furnace slag. Moreover, identical tests are also conducted considering the amount of powder, the mixing ratio of alkali activator and the mixing ratio of silica fume for further comparative analysis considering various variables. The comparison with the formulae specified in Korean and overseas codes reveal that a mixing ratio of 18% is adequate for the alkali activator and that a replacement ratio of 5% by silica fume is recommended for silica fume. The elastic modulus of the geopolymer concrete appears to increase slightly with the increase of the compressive strength per variable and age and to be smaller than the values predicted by the formulae specified in Korean and overseas codes. In addition, the examination of the stress-strain curves shows that the geopolymer concrete exhibits ductile behavior compared to the conventional OPC. In view of the splitting tensile strength, high strength is observed for a powder content of
and a replacement ratio of 18% by silica fume. The resulting ratio of the compressive strength to the splitting tensile strength is seen to range between 8.7 and 10.2%.
Autogenous Shrinkage Properties of High Strength Alkali Activated Slag Mortar
Oh, Sang-Hyuk ; Hong, Sung-Hyun ; Lee, Kwang-Myong ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 60~65
DOI : 10.14190/JRCR.2014.2.1.060
Recently, lots of researches on alkali-activated slag (AAS) concrete have been carried out to resolve the environmental issues such as recycling by-products and global warming. AAS concrete would have high strength and high level of durability. On the other hand, it is known that large amount of shrinkage occurred in AAS concrete due to rapid alkaline reaction in the early age, and however, the related studies about autogenous shrinkage of high strength AAS mortar are relatively rare. In this study, fresh mortar properties such as flow and setting time, compressive strength and autogenous shrinkage of AAS mortar with W/B=0.40 to 0.50, were measured. AAS mortar was activated with sodium silicate (Ms=1.0) with 5, 6 and 7 % of
. Test results revealed that AAS morar shows larger autogenous shrinkage than OPC mortar and the lower W/B of AAS mortar, the greater autogenous shrinkage. Therefore, the application of appropriate curing and the use of shrinkage reduction admixture would be needed to reduce autogenous shrinkage of AAS mortar.
Improved Durability Performances in Cement Mortar with Rice Husk Ash
Saraswathy, Velu ; Karthick, Subbiah ; Kwon, Seung-Jun ;
Journal of the Korean Recycled Construction Resources Institute, volume 2, issue 1, 2014, Pages 66~73
DOI : 10.14190/JRCR.2014.2.1.066
Currently many researches have been performed for enhancing durability of concrete. Rice husk ash has several advantages like early strength of concrete and dense pore structure. A calcium silicate hydrate (CSH) gel around the cement particles due to pozzolanic reaction of rice husk can increase the strength of concrete against cracking. Very limitedly a systematic and detailed investigation on the corrosion performance of rice husk ash and silica fume blended concrete is performed. A realistic approach has been made through compressive strength, bond strength, and split tensile strength etc. Corrosion performance was also evaluated rapid chloride ion penetration test (RCPT) and impressed voltage test, and the results were discussed in the paper.