The Surface Area of Hardened Cement Paste as Measured by Various Techniques

Hydrated cement paste has a high specific surface area due almost entirely to the calcium-silicate-hydrate reaction product. The surface area of cement paste is closely related to many crucial properties, including strength and permeability, and is therefore a useful predictive measurement. It is also a useful parameter for studying the nature of the calcium-silicate-hydrate gel itself. Unfortunately, the surface area of cement paste is difficult to measure accurately, and different techniques have given widely varying values. This review discusses these different techniques, summarizes the surface area results given by each, and attempts to rationalize the differences in these results by considering the different physical principles by which each technique generates a surface area value.