Research on the early hydration properties of C3A prepared by sol–gel method

Abstract

The results of hydration of C3A (tricalcium aluminate), prepared by the sol—gel method, for up to 18 h are presented. The hydration heat and heat of evolution were determined by an isothermal calorimeter. The hydration process was divided into three stages and the degree of hydration of the pastes at different stages was analysed by X-ray phase analysis without standards. The ion concentration of the hydration solution was determined using a filter method by X-ray fluorescence and inductively coupled plasma. When the C3A powders were in contact with initially pure water, Ca2+ and aluminate anions were released rapidly. In the first few minutes the C3A powders reacted with water very rapidly and Ca(OH)2 crystals more readily formed at higher rather than lower hydration temperatures. C3AH6 was the main hydration product in the early stage.