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Formation Behavior of Microporous Ettringite Body by Hydration of Tricalciumaluminate Clinker and Gypsum

알루민산삼칼슘 클링커와 석고의 수화에 의한 에트린자이트 미세다공체 생성거동

  • Na, Hyeon-Yeop (Department of Advanced Materials Engineering, Kyungnam University) ;
  • Song, Tae-Woong (Department of Advanced Materials Engineering, Kyungnam University)
  • 나현엽 (경남대학교 신소재공학과) ;
  • 송태웅 (경남대학교 신소재공학과)
  • Published : 2008.11.30

Abstract

Ettringite$(3CaO{\cdot}Al_2O_3{\cdot}3CaSO_4{\cdot}32H_2O)$, one of the hydrated phase of Portland cement is usually formed in the early stage of hydration by the reaction of tricalciumaluminate$(C_3A)$ and gypsum. The rapid and strong crystal growth of separated rod-shaped ettringite have been utilized for the preparation of special cements of rapid setting, high strength and non-shrinking properties. The ettringite also has been noticed as a promising materials for the immobilization of various waste ions because of its unique crystal structure which has abundant channels and exchangeable ionic compounds. In this study, the formation and growth behavior of the ettringite was investigated in the system $C_3A-CaSO_4-H_2O$ using $C_3A$ clinker and gypsum to obtain a microporous body for waste ion immobilization. Ettringite was revealed to form by the dissolution-precipitation mechanism and the bulk body was by the entangled growth of rod-shaped ettringite crystals. The hardened body was composed of nearly pure rod-shaped ettringite interlocked each other with adequate mechanical strength. The homogeneity of structure, pore size, specific surface area and porosity of the hardened body were influenced by reaction temperature, water/powder ratio and the curing time. The hardened body prepared with water/powder ratio of 1 at $24^{\circ}C$ for one day showed excellent morphological properties for the purposed materials.

Keywords

References

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