EFFECT OF Al AND Mg ON FORMATION AND CRYSTAL OF TOBERMORITE

Abstract

The purpose of this study is to consider the effects of addition of Al and Mg on the formation and crystal of tobermorite. The samples were synthesized in different conditions of curing （autoclave curing or hydration curing at 80℃） and additional materials （gehlenite, akermanite, and gehlenite-akermanite） which are known as industrial by-products. Therefore, this study will contribute in terms of developing sustainable society. As a result, 1.1nm tobermorite which was including Al was generated by addmixing gehlenite or gehlenite-akermanite under high pressure and high temperature condition （autoclave curing）. In addition, the large amount of Al in gehlenite or gehlenite-akermanite replaced Si at bridging site in 1.1nm tobermorite. Furthermore, the interlayer spacing of 1.4nm tobermorite got narrower to 1.1nm without strong drying after 80℃ hydration. This was due to replacing Si to Al in gehlenite, and SiO4 tetrahedra at bridging site was tied together and interlayer spacing got narrower. This result is great step to realize a material design to produce 1.1nm tobermorite in concrete at low temperature. On the other hand, the amount of 1.1nm tobermorite increased by admixture akermanite under high pressure and high temperature condition. But akermanite was hard to react at low temperature condition such as 80℃.