Ettringite formation in soil-cement interaction process

It is reported that during the hydration of cement more than twenty three minerals form. Parts of these minerals contribute to the strength of cement. However, there are few minerals in the process of cement hydration which are responsible for expansion and deterioration of cement and concrete. Ettringite is known as one of the important minerals which forms in the process of cement hydration. Sulfate resistance cement can be used to prevent the ettringite formation due to excluding alumina ions in its production process. However, clayey soils might contribute to the formation of ettringite due to the solubility of alumina ions at high pH in vicinity of concrete. This paper addresses some of the fundamental aspects of ettringite formation in concrete and the role of clayey soils in its formation in the vicinity of concrete. In this paper the main aspects of hydration process of Portland cement is addressed. With explanation of the major components for ettringite formation the possible situation about the formation of ettringite at the vicinity of clayey soils is pointed out. The results of this paper show that the presence of clayey soils in vicinity of concrete might enhance the ettringite formation in concrete.