Case III. Influence of Cement Particle Size Distribution on Properties

A series of cement paste microstructures with varying cement particle size distributions (and, therefore, varying surface areas) were created and cured using the VCCTL models (see Figure 10.3.9). The hydration performance and various performance properties were computed, with the following results:

• Coarser cements significantly reduce early-age hydration rates and heat release (and strength development), thus may require that more attention be paid to proper curing.

• At equivalent degrees of hydration, diffusivities of "fine" and "coarse" cements are similar.

• Coarser cements significantly reduce autogenous shrinkage.

Figure 10.3.9. Two-dimensional images of model cement powders of various finenesses (w/c=0.35). The particle size distribution and phase structure of each cement were taken from real cement powders.