| abstract |
Cementitious compositions in which the cementitious properties of fly-ash are carefully controlled. The cementitious compositions may be substantially free harsh acids and bases such as citric acids (~ pH 2.2) and alkali metal activators including alkali hydroxides (~ pH 12-14) and metal carbonates (~ pH 11.6). The use of these harsh chemicals creates acid base reactions during use of the products. Instead of these harsh chemicals, a citric salt, for example potassium citrate, may be used as a reaction accelerator. Boric compounds may be used as a retarder in the compositions. |