• Journal of the Korea Institute of Building Construction
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• v.14 no.3
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• pp.252-258
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• 2014

With the vision of 'a low carbon green develop' various industrial by-products were used as replacement of cement, in order to reduce $CO_2$ emissions from the manufacturing process of cement. Blast furnace slag is one of the industrial by-products. Due to the similar chemical compositions to ordinary Portland cement, blast furnace slag have been widely used in concrete with minimum side effects. Hence, in recent years, alkali activated slag-based composites are extensively studied by many researchers. However, the alkali activator can cause a number of problems in practice. Therefore, in this study, an alternative way of activating the slag was investigated. To activate the slag without using an alkali activator, calcium sulfate dihydrate was chosen and mixed with natural recycled fine aggregate. Fundamental properties of the slag-based mortar were tested to evaluate the effect of calcium sulfate dihydrate.

• Cement
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• s.200
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• pp.36-39
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• 2013

포틀랜드 시멘트만이 유일하던 지난 1976년, 제설과정에서 발생하는 부산물인 슬래그(slag)를 재활용한 시멘트를 국내 최초로 생산한 한국C&T(주)는 1985년 무재해 3배 달성업체로 노동부 은탑산업상을 수상한 바 있으며 1986년 증권감독원으로부터 우량기업으로 선정되는 등 양질의 슬래그 시멘트 생산을 통해 연관산업 발전에 이바지해왔다. 신뢰에 기반을 둔 경영과 끊임없는 기술개발을 토대로 2014년 힘찬 도약을 준비해 나가고 있는 한국C&T(주) 김훈석 대표이사를 만났다.

• Magazine of RCR
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• v.13 no.4
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• pp.42-47
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• 2018

• Cement Symposium
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• no.25
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• pp.102-109
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• 1997

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.149-156
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• 1997

In order to improve compressive strength of cement mortar, powder admixture(FAS) was mmufactured by mixing fly ash. Il-anhydite and silica hume, and superplasticizer was used for the control of fluidity reduction with the use of this admixture. Cement was substituted by 10, 20wt% of FAS respectively. At W/S = 0.40, the fluidity of' cement paste substituted by PAS was decreased. NSF and NT-2 were very effective fbr the control of fluidity reduction. As the particle size of U -anhydrite was fine, the fluidity of cement mortar was increased. The fluidity reduction of cement mortar substituted by 10wt% of FAS was controlled. The compressive strength of cement mortar substituted by 10wt% of FAS showed higher. value than that of 20wt%, expecially specimen(C1) substituted by 10wt% of $\gamma$ had the highest compressive strength value.

• Resources Recycling
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• v.14 no.2
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• pp.10-18
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• 2005

The manufacture property of anhydrous calcium sulfate (anhydrite Ⅱ) from flue gas desulfurization (FGD) gypsum discharged from domestic thermoelectric power plants to apply as an auxiliary material of cement and concrete by high temperature treatment were investigated. The FGD gypsum was completely converted to anhydrite Ⅱ at the temperature of 700$^{\circ}C$ and the retention time of 1 hr. In the phase transformation process, particle size was also changed. The chemical composition, particle size and heat property of anhydrite Ⅱ made from the FGD gypsum were similar to them of natural gypsum. In the leaching test of sulfate ion (SO$_4^{2-}$) at the temperature of 90$^{\circ}C$ and the retention time of 1 hr, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ that was sintered at 700$^{\circ}C$ for 1 hr was about 50 wt.% based on that of natural gypsum. In addition, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ by adding the slaked lime of 3 wt.% decreased about 70 wt.% comparing with that of natural gypsum. In the application test, the compressive strength of cement and concrete manufactured by using the anhydrite Ⅱ as an auxiliary material were similar or superior compared with them of cement and concrete done by natural gypsum as an auxiliary material.

• Journal of the Korean Wood Science and Technology
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• v.8 no.1
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• pp.1-12
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• 1980

경화촉진제로서 염화칼슘, 경화억제제로서 수크로오즈를 처리한 포트렌트시멘트의 양생효과를 전자현미경에 의해 관찰한 결과, 경화억제제를 처리한 시멘트는 결정을 이루지 못하고 융기상태로 남아있고, 경화촉진제를 처리한 시멘트는 겔형으로 변한후 육각형의 결정을 이루는 것이 관찰되었다. 또한 시멘트-목재 복합체의 양생은 좀 다른 양상을 보이고있어 경화제가 처리된 WCC는 포플러 스리버 표면에서 작은 융기가 겔상의 표면에 많이 관찰되나 무처리는 거의 일정한 모양의 입자가 관찰되어 시멘트 경화촉진제와 억제제의 효과를 구명하였다.

• Cement
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• s.192
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• pp.39-47
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• 2011

최근 온실가스 감축과 기후변화 그리고 녹색성장에 대한 관심증대와 더불어 시멘트 분야의 연구 생산분야는 천연자원 사용량을 줄이고, 소성공정을 도입하지 않은 새로운 개념의 무기바인더가 다시 고개를 들고 있다. 다른 용어로는 비소성, 무시멘트 등으로 표현되기도 하는데, 광의의 개념으로 보면 알칼리 활성화제를 사용한 비소성 무기결합재인 지오폴리머가 바로 그것이다. 지오폴리머 결합재는 1957년 우크라이나의 토목공학회에서 개발한 알칼리 활성 슬래그시멘트에 기원을 두고 있고, 1970년대 말 프랑스의 다비도비치에 의해 지오폴리머라는 용어가 처음 사용되기 시작했다. 알칼리 활성 무기결합재(Alkali-activated inorganic binder)의 정의이다. Alkali-activated inorganic binder는 원래는 결합능력이 없던 재료에 대해서 Alkali-activating 용액을 첨가했을 때, 시멘트처럼 결합능력을 가지게 되는 모든 종류의 결합시스템을 말한다. 국내에도 이미 2000년 초부터 지오폴리머의 개념을 도입한 제품이 상업화되어 오랫동안 품질검증을 거쳐 안정성이 확인되고 있다. 최근에 다시 전남대가 그 동안의 연구성과를 발 빠르게 중소기업에 기술 이전하여 소위 무시멘트 시대에 진입하는 분위기이다. 지난 9월 동아에스텍(주)과 조인트벤처 설립을 위해 손을 잡았고, 사업화가 곧 진행될 것으로 보인다. 이를 계기로 국내에도 무시멘트회사가 본격적으로 등장하게 된 것이다. 따라서 본 고는 무시멘트의 개념을 잘 표현한 문헌으로 일본콘크리트공학 연차논문집, 2010년 1월호를 번역 요약 발췌한 것이다.

• Composites Research
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• v.25 no.4
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• pp.110-116
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• 2012

Recently, the development and field applications of Ternary Blended Cement(TBC), where blast furnace slag and fly ash are recycled in Ordinary Portland Cement(OPC) in order to obtain improvements in the durability and heat of hydration reduction performance in large scale civil structures, have been increasing. Also, there are continuing efforts by construction companies to reduce the construction time with the aim of reducing construction costs. Therefore, there is a need to improve the performance of TBC, which has a relatively slow early strength development. In order to improve the early strength of TBC mortar, the compressive strength, SO3 content, and SEM analysis was determined in this study on mortar with the fineness and content of blast furnace slag and anhydrite regulated. As a result, to secure the early strength of TBC mortar, using blast furnace slag with a fineness of approximately $4,200cm^2/g$, adding 3.5% anhydrite with a fineness of approximately $10,000cm^2/g$, and managing the $SO_3$ content to roughly 3.72% was found to provide the most outstanding early strength properties.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.801-809
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• 2006

Epoxy resin has widely been used as adhesives and corrosion-resistant paints in the construction industry for many years, since it has desirable properties such as high adhesion and chemical resistance. Until now, in the production of conventional epoxy cement mortars, the use of any hardener has been considered indispensable for the hardening of the epoxy resin. However we have noticed the fact that even without any hardener, the hardening process of the epoxy resin can proceed by the action of hydroxides in cement mortars. As a result the disadvantages of the two-component mixing of the epoxy resin and hardener have been overcome. The purpose of this study is to evaluate the mechanical properties and durability of epoxy cement mortar without a hardener exposed at indoor and outdoor for one year. The epoxy cement mortars without and with a hardener were prepared with various polymer-cement ratios, and tested for weight change, flexural and compressive strengths, water absorption, carbonation depth and pore size distribution. Especially, the basic properties of the epoxy cement mortars without hardener are discussed in comparison with ones with the hardener. From the test results, it is concluded thai the epoxy cement mortars without a hardener exposed at indoor and outdoor for one year have higher strength and better durability than ones with the hardener within the polymer-cement ratios of 10 to 20%.