Question

Reactions and reactivities of compounds in hydraulic cements

Answer 1

The initial reactions with water of the compounds present in Portland and some other hydraulic cements are ones of proton transfer, in which the compounds act as bases. Factors affecting the reactivities of individual compounds include the charges on the oxygen atoms, other chemical or structural features, types and concentrations of defects and formation of protective layers of reaction products. Physical factors, such as particle size distribution and microstructure of the starting material, are also very important. Some hydraulic cements contain one or more constituents that act as bases and one or more that act as acids. With yet others, some or all of the initial processes are simple dissolutions.