• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.135-146
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• 1996

In this study, the properties of super flowing concrete containing fly ash were experimentally investigated and compared with those of ordinary concrete. Tests were carried out on five types of super flowing concrete mixes containing fly ash and three types of ordinary concrete mixes without fly ash. Flow test, 0-funnel test, box test, L type test and slump test were carried out to obtain the properties for flowability and workability of fresh concrete. The mechanical properties of hardened concrete were also investigated in terms of compressive strength, splitting tensile strength, modulus of elasticity, creep and drying shrinkage. In fresh concrete, it was found that super flowing concrete had excellent workability and flowability compared with ordinary concrete, and had self-compactable performance. Super flowing concrete *also had good mechanical properties at both early and late ages with compressive strength reaching as high as 40 MPa at 28 days. The creep deformation of super flowing concrete investigated was relatively lower than that of ordinary concrete, but drying shrinkage was much higher.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.617-620
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• 2008

When fresh concrete is exposed to the cold weather, the concrete may happen frost damage because of freezing at early ages and the strength development may be go down. Therefore, this paper is intend to investigate the properties and availabilities of cold weather concrete using anti-freeze based formate-acetate for ensure of excellent concrete quality on cold temperature. According to test result for concrete in anti-freeze agent, strength properties in sub-zero temperature increases in comparison with concrete of non anti-freeze agent without decline of strength until later age. When anti-freezing agent is added by 3.0% to binder, it gives good effects on the performance of the fresh and harden concrete.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.491-498
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• 2012

This study examines setting shrinkage, coefficient of thermal expansion, and elastic modulus of unsaturated polyester( UP)-methyl methacrylate(MMA) polymer concrete, which is generally used for repair of portland cement concrete pavement and manufacturing of precast products. In this study, a series of laboratory test were conducted with variables such as UP-MMA ratio, shrinkage reducing agent (SRA) content, and test temperature. The results showed that the setting shrinkage ranged from 29.2 to $82.6{\times}10^{-4}$, which was significantly affected by test temperature. Moreover, the findings revealed that the coefficient of thermal expansion, elastic modulus and ultimate strain of UP-MMA based polymer concrete ranged from 21.6 to $31.2{\times}10^{-6}/^{\circ}C$, 2.8 to $3.3{\times}10^4$ MPa, and 0.00381 to 0.00418, respectively. The results of this study will be used as important data for design and application of UP-MMA based polymer concrete.

• Proceedings of the KAIS Fall Conference
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• 2000.10a
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• pp.237-240
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• 2000

본 연구에서는 비스페놀 A, 에피크로로히트린을 반응시킨 에폭시 기본주제를 중심으로 경화제, 희석제, 충진제, 촉매 등을 배합하여 토목, 건축용 반고체형 에폭시 접착제를 개발하였다. 여기서 특히 에폭시 주제와 희석제의 종류 및 배합비율에 따른 기본 물성, 접착성능 등을 측정하였다. 상온 경화 특성을 측정하기 위하여 경화시 간을 측정한 결과 희석제의 종류와 관계없이 희석제의 양이 증가할수록 경화시간이 증가하고 경화온도도 증가하는 경향을 알 수 있었으며 촉매의 양이 적을 경우가 경화시간이 빠른 것을 알 수 있었다. 또한 경화 시간은 30분 내지 40분 정도로 상온에서 사용할 수 있을 것으로 기대한다. 접착력 시험 결과는 촉매의 양이 적당한 때 가장 좋은 접착력을 나타내고 희석제 중에서 HDGE의 경우가 가장 좋은 접착력을 나타내었고 희식제의 양이 증가할수록 접착력은 증가하였다. 실리카와 철분을 섞어 반고체형 에폭시 접착제를 제조한 경우 기존의 제품보다 우수한 접착력을 나타내었다. 따라서 본 연구에서 개발한 반고체형 접착제는 제조공정 코스트 등에 대한 검토와 함께 제품화하여 토목, 건축 분야의 콘크리트 균열 접착, 볼트와 콘크리트의 접합, 목재의 접합 등에 간편하게 사용될 수 있으며, 배합물질과 비율에 따라 전기전자. 토목건축, 자동차산업 등의 산업용 접착제로서 응용될 수 있을 것으로 기대된다.

• Magazine of the Korea Concrete Institute
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• v.14 no.6
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• pp.49-54
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• 2002

아직까지 우리나라에서 폴리머 시멘트 콘크리트가 콘크리트와 같이 광범위하게 사용되고 있는 것은 아니지만 건설재료로서의 사용이 증가하는 추세에 있다. 폴리머 콘크리트의 제조에는 결합재로서 물이나 시멘트가 전혀 사용되지 않고 수지(resin)만을 사용한다. 각종 수지가운데 많이 이용되고 있는 것은 에폭시 수지, 불포화 폴리에스테르 수지, 우레탄 수지, 퓨란 수지 등이 있다. 그러나 원료사정이 국가마다 다르기 때문에 폴리머 콘크리트의 결합재로 사용되는 액상수지 역시 차이가 있다. 우리나라의 경우는 에폭시수지, 불포화 폴리에스테르 수지 및 우레탄 수지가 주로 사용되고 있으며, 가까운 일본의 경우는 폴리머 콘크리트의 결합재로서 워커 빌리티, 저온경화성, 내후성 등이 우수한 메타크릴산 메틸도 사용되고 있다. 또한 폴리머 모르타르 및 콘크리트의 경화반응에 방해를 주지 않도록 충전재 및 골재 등은 건조시켜 함수율이 0.5 % 이하가 되도록 사용하고 있으나, 지금은 흡수제, 가교제 등의 혼화재료가 개발되어 함수율을 3% 까지 허용하고 있으며, 지금까지 불가능하게 생각되었던 폴리머 콘크리트에 대한 레디믹스트 콘크리트(레미콘) 개발도 흥미를 끌고 있다.(중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.497-498
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• 2009

Unsaturated polyester(UP) and epoxy resin require 8${\sim}$11 hours long harding times and heating systems used by reinforcement liner. This study is to evaluate the effects of low temperature harding property of UP with methyl methacrylate(MMA) monomer mixing proportions.

• 레미콘
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• no.7 s.60
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• pp.71-78
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• 1999

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.117-124
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• 2006

The effects of binder content and recycling mixed waste plastics(PA) content on the workability, work life and hardening shrinkage of fresh polymer concrete using mixed waste plastics are examined. As a result, the workability of the polymer concretes using mixed waste plastics tend to improve with increasing binder content, PA content and filler content. The work life of the polymer concretes using mixed waste plastics is shortened with an increase in the initiator content and curing temperature. The length change of the polymer concretes using mixed waste plastics tend to increased with Increasing binder content and PA content. The result of the present research is expected to make a contribution to the recycling of final mixed waste plastics and the continuing efforts for the development of use of the recycled products are thought to expand the horizon for the recycling of the final mixed waste plastics.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.391-398
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• 2011

After a concrete is poured, reinforced concrete structures were distressed by physical and chemical factor over time. It is in need to define important variables related to structural behavior for effectively conducting seismic analysis of structures with age-related degradation. In this study, a sensibility analysis using the first-order second moment method was performed to analyze an important variables for the reinforced concrete shear wall with age-related degradation. Because the seismic capacity of aging structures without a concrete hardening effect can be underestimated, the sensibility of analysis variables was analyzed according to the concrete hardening. Important variables for RC shear wall with age-related degradation was presented by using the tornado diagram.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.791-796
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• 1998

Air voids existed in hardened concrete have an important influence on concrete deterioration such as carbonation, freezing and thawing, and corrosion of embedded steel in concrete. Therefore it is very significant to investigate the pore structure of system(size, number and continuity of air voids) to solve the reason caused concrete deterioration. The purpose of this study is to develop the standard method of measuring air voids which affect properties in hardened concrete using image analyzing system. This paper presents the settlement of rapid and exact experimental method which extracts fine bubbles, calculates the number of air voids, and determines air-void distribution using image analyzing system with computer.