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Hydrate Characteristics of Cement Mixtures with Expansion Additive According to Age and Improvement Effect on Initial Strength

팽창재를 사용한 시멘트 혼합물의 재령별 수화물의 특성과 초기강도 개선 효과

  • Song, Tae-Hyeob (Building Research Department, Korea Institute of Construction Technology) ;
  • Park, Ji-Sun (Building Research Department, Korea Institute of Construction Technology) ;
  • Lee, Sea-Hyun (Building Research Department, Korea Institute of Construction Technology)
  • 송태협 (한국건설기술연구원 공공건축연구본부) ;
  • 박지선 (한국건설기술연구원 공공건축연구본부) ;
  • 이세현 (한국건설기술연구원 공공건축연구본부)
  • Received : 2013.10.01
  • Accepted : 2013.10.15
  • Published : 2013.10.27

Abstract

CSA, a cement mineral compound that is mainly composed of $3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4$, generates ettringite as a hydration product after a reaction with glass (lime), gypsum and water to speed up the hardening process and enhance the strength and degree of expansion. When used as a cement admixture, there is increased production of ettringite, which can improve the initial strength in the first three days and ameliorate the reduction in the initial strength caused by the use of fly ash in particular. In this study, a hydrate analysis was performed using XRD and SEM after substitution with fly ash (30%) and CSA (8%) with the goal of observing the effect of CSA on the initial strength of a cement mixture containing fly ash. The results of the analysis showed that an addition of CSA promoted the production of ettringite and improved the initial strength, resulting in the generation of hydrates, which can effectively enhance the long-term strength of these materials.

Keywords

References

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