Avaliação de pastas de cimento Portland contendo cinza pesada moída

Abstract

In this study, the influence of adding ground coal bottom ash in Portland cement pastes was evaluated. Blended cements were prepared with ground bottom ash of three distinct particle size distributions and sub-stitutions, by volume, of 10%, 30%, and 50%. For each blended cements, pastes were prepared with water to binder ratios of 0.35 and 0.40, by mass. Early age hydration was investigated by isothermal calorimetry. Af-ter being subject to wet curing, the pastes were tested for thermogravimetric analysis, insoluble residue con-tent and compressive strength tests at 7, 28, and 91 days. Degree of hydration increased with the addition of ground bottom ash for all fineness and replacement contents. Increase in heat evolution and compressive strength, along with the decrease in the insoluble residue content, lead to the conclusion that the added ground bottom ash acted both chemically and physically in the hydration of the blended cements. The find-ings suggest that the ground bottom ash could replace up to 50% of the ordinary Portland cement without compromising compressive strength at 91 days of hydration.