본 연구는 최근 친환경 대체 시멘트로 주목받고 있는 칼슘설포알루미네이트(calcium sulfoaluminate, CSA) 시멘트의 수화 반응을 탐구한다. 배합수 및 석고의 첨가량에 따른 페이스트 배합실험을 하였으며, X-선 회절(X-ray diffraction, XRD)실험을 통해 각 변수 및 재령 일에 따른 광물 상(mineralogical phase)을 정량분석하였다. 클링커 광물의 정량분석 결과를 입력 값으로 깁스 에너지(Gibbs energy) 최소화 계산을 통한 CSA 시멘트의 수화반응 모형을 도출하였다. 배합수의 증가는 CSA 시멘트의 수화반응을 촉진 및 향상하는 것으로 조사되었으며, 석고 첨가량 증가에 따라 CSA 시멘트의 완전 수화를 위한 최소 요구 배합 수량이 증가하는 것으로 조사되었다.

This study evaluated the standard consistency, setting time, hydration heat, and compressive strength of binary blended cement concrete (general and high strength) using air cooled ladle furnace slag (LFS) of 3, 5, 7, 10wt.% as an admixture for ordinary portland cement (OPC). Results showed that binary blended cements using the LFS of lower than 5wt.% shortened the setting time and reinforced the compressive strength of concrete (general and high-strength) compared to OPC concretes although binary blended cements needed more water to achieve the standard consistency. This indicated that LFS could be used as a useful admixture for manufacturing binary blended cement. Thus, we expected that the upcycling of LFS would be contributed to save energy consumption and reduce the greenhouse gas emission from the field of cement industry.

The phenomenon of leaching consists in the dissolution of solid calcium in cement hydrates when concrete is exposed to any aggressive solution. Calcium leaching is completely controlled by the thermodynamic equilibrium between cement hydrates and the porous solution. Thus, it might be described by considering the hydrates (C-S-H and aluminates) solubility evolution with pH. Nevertheless a simplifed model has been proposed considering only the different calcium phases of the hydrates. This study suggested definition of calcium leaching density with type of cement hydrate.

The purpose of this study is to explore the time dependant behaviors of chloride ions adsorption with cement hydrates, focused on its mechanism. AFt phase and CH phase were not able to absorb chloride ion, however, C-S-H phase and AFm phase had a significant chloride adsorption capacity. Based on the results, this study suggested theoretical approach to depict chloride adsorption behavior with elapsed time of C-S-H phase and AFm phase effectively. AFm phase showed a slow chemical adsorption in 40 days, while C-S-H phase showed binding behavior with 3 stages including the stage of instantaneous physical adsorption other stages.