Formation of hydrogarnets: Calcium hydroxide attack on clays and feldspars

Abstract

The reaction of calcium hydroxide with sericite, with shale and with a few igneous rocks gives hydrogarnets, hydrated calcium silicates and free alkalies. In the experiments described, slurries of the hydroxide and the starting materials were boiled (95 °C). Hydrothermal treatment was carried out at 1 MPa and at 2 MPa. The full significance of the findings is unknown but the possible unfavourable influence of these reactions on the durability of concrete is considered.