Ettringite formation expansion and crystallization pressure a thermodynamic approach

Existing literature on the formation of ettringite (both early and delayed ettringite formation), their stability and expansion leading to damage in concretes have been reviewed. Crystallization pressure due to ettringite expansion may be one of the important causes of crack formation in hardened concretes. It is suggested that a crystal of ettringite will grow only when there is a crystal nuclei of critical size. Based on thermodynamic considerations, an equation has been derived to calculate the crystallization pressure.