• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.189-192
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• 1998

The mechanical properties of alkali resistance (AR) glass fiber reinforced cement(GFRC) under different curing conditions were investigated in this study. The specimens were formed by extrusion process, and then steam cured and autoclaved. An autoclaved specimen showed the elastic-brittle behavior up to 4% of fiber volume fraction. However, it was found that the fracture behavior for cured specimen was changed to the elastic-plastic with crack branches fracture at greater than 3 vol.% of fiber.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.117-137
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• 2012

In the ALC(Autoclaved lightweight concrete) manufacturing process, if the pre-cured semi-cake is removed after proper time is passed, it will be hard to retain the moisture and be easily cracked. Therefore, in this research, we took the research by multiple regression analysis to find relationship between variables for the prediction the hardness that is the control standard of the removal time. We study the relationship between Independent variables such as the V/T(Vibration Time), V/T movement, expansion height, curing time, placing temperature, Rising and C/S ratio and the Dependent variables, the hardness by multiple regression analysis. In this study, first, we calculated regression equation by the regression analysis, then we tried phased regression analysis, best subset regression analysis and residual analysis. At last, we could verify curing time, placing temperature, Rising and C/S ratio influence to the hardness by the estimated regression equation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.199-200
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• 2023

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.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.2
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• pp.101-111
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• 2012

In the ALC(Autoclaved lightweight concrete) manufacturing process, if the pre-cured semi-cake is removed after proper time is passed, it will be hard to retain the moisture and be easily cracked. Therefore, in this research, we took the research by multiple regression analysis to find relationship between variables for the prediction the hardness that is the control standard of the removal time. We study the relationship between Independent variables such as the V/T(Vibration Time), V/T movement, expansion height, curing time, placing temperature, Rising and C/S ratio and the Dependent variables, the hardness by multiple regression analysis. In this study, first, we calculated regression equation by the regression analysis, then we tried phased regression analysis, best subset regression analysis and residual analysis. At last, we could verify curing time, placing temperature, Rising and C/S ratio influence to the hardness by the estimated regression equation.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.437-442
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• 1998

In order to investigate the mechanical properties of several fibers for reinforced cement these speciments with 2wol% of ARG and organic fibers were formed by vacuum extrusion process. After steam curing and autoclaving the flexural strength and the elastic modulus of FRC were measured. It was found that the ARG-FRC showed the elastic-brittle fracture behavior in both steam cured and autoclaved condition. And also the steam cured PP and PVA-FRC had elstic-plastic behavior but their ductility were reduced and changed to the elastic-brittle after autoclaving This change in mechanical behavior was found to be related to the thermal stablity of thes organic fibers.

• Advances in concrete construction
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• v.8 no.2
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• pp.139-144
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• 2019

In this study, the mechanical properties of reactive powder concrete (RPC) with a constant cement to silica fume ratio of 4 were investigated. In the experimental program, reactive powder concretes with steel fiber at different ratios were produced. Five productions using quartz sand with a maximum grain size of 0.6 mm were performed. A superplasticizer with a ratio of 3% of the cement was used for all productions. $40{\times}40{\times}160mm$ prismatic specimens were prepared and tested for flexural and compression. The specimens were exposed to two different curing conditions as autoclave and standard curing condition. Autoclave exposure was performed for 3 hours under a pressure of 2 MPa. It was observed that the compressive strength of concrete, along with the flexural strength exposed to autoclave was quite high compared to the strength of concretes subjected to standard curing. The results obtained indicated that the compressive strength, along with the flexural strength of autoclaved concrete increased as the amount of cement used increases. Approximately 15% increase in flexural strength was achieved with a 4% steel fiber addition. The maximum compressive strength that has been reached is over 210 MPa for reactive powder concrete for the same steel fiber ratio and with a cement content of $960kg/m^3$. The relationship between compressive strength and flexural strength of reactive powder concrete exposed to both curing conditions was also identified.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.67-70
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• 1992

1930년 스웨덴에서 개발에 성공, 네덜란드에서 더욱 발전시킨 ALC(Autoclaved Light-weignt Concrete의 약칭) 는 가볍고, 견고하고, 그리고 시공이 간편한 경제적인 요건들을 충족시키는 건축자재로 세계적으로 널리 사용되고 있으며 , 국내에서는 불과 수년 전부터 연구 개발되고 있는 실정이다. ALC 란 시멘트와 규사, 생석회등 무기질 원료를 고온,고압으로 증기 양생시킨 경량의 기포 콘크리트 제품을 통칭한 것이다. ALC공정은 bulk ALC를 생산하는 batch공정과 이 bulk ALC에 대한 처리 공정으로 크게 나눌 수가 있으며 여기에서는 bulk ALC 처리 공정을 side shield treatment, anti-corrosion treatment, curing grate transferer, cutting station, curing car transportation, autoclave traveling platform, 및 packing 의 공정으로 세분하여 각 공정개요 소개 및 PLC(Programmable Logic Controller의 약칭)를 이용한 제어 system에 대하여 설명하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.373-374
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• 2010

This study is to search for recycling method of the WCP(waste concrete powder). From the experiment analysis on the chemical composition, we confirmed that $SiO_2$ was occupied about 60% of WCP. To investigate the applicability of WCP as replacement material of Quartz, we tested the properties of autoclaved light weight concrete containing WCP. As a results, when increasing the replacement of WCP, compressive strength decreased and pore diameter did not change. On the other hand, when increasing curing times, compressive strength and pore diameter increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.57-60
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• 2005

This is the experimental study on the strength development of the light weight concrete block according to the autoclaving time. The calcareous source used the cement, siliceous material used the bottom ash ground to fine particle, and the PP fiber used to increase toughness. The results of this experiment are as follows. According to the increase of autoclaving time and the fiber content, compressive and flexural strengths are increased. Despite of the changes of the autoclaving time, tobermorite was produced on each of the specimens. However, the phase of tobermorite was changed in accordance with the changes of autoclaving time.

• Journal of the Korea Institute of Building Construction
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• v.8 no.3
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• pp.93-99
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• 2008

The purpose of this study is to evaluate the bond strength and corrosion resistance of coated reinforcing bar using hybrid-type polymer cement slurry(PCS). PCS coated steels, which is made from two types of polymer dispersions such as St/BA and EVA are prepared, and tested for bond strength and various corrosion resistances such as autoclaved cure, carbonation and H2SO4 solution. From the test results, the bond strength of PCS coated reinforcing bar using ordinary portland cement at 1-5, 2-1 and 4-5 of mixes is higher than that of uncoated regular steel. However, bond strength of almost PCS coated reinforcing bars using ultra rapid high strength cement is higher than that of epoxy coated bar, is also in ranges of 102% to 123% compared to that of uncoated regular steel. In autoclaved accelerating test, the ratio of corrosion of uncoated regular steel is increased with the increase in NaCl content, but the corrosion of PCS coated steel was very small. In the acceleration test for carbonation, increasing the amount of NaCl the corrosion of coated steel did not produce. The corrosion of uncoated regular steel is increased with the increase in the amount of NaCl. It can be seen that the NaCl following the acceleration test for carbonation can lower the corrosion resistance of concrete. As a result, the corrosion of steel largely is affected by the acceleration curing, chloride ion penetration and carbonation and shown more severe corrosion by applying complex factors. These corrosions of steel can be suppressed by the coating of PCS.