Title: Effect of Ultrafine Particles on Heat of Hydration of Cement Mortars

Author(s): El Hadj Kadri and Roger Duval

Publication: Materials Journal

Volume: 99

Issue: 2

Appears on pages(s): 138-142

Keywords: alumina; calcite; mortar; pozzolan; silica fume.

DOI: 10.14359/11705

Date: 3/1/2002

Abstract:
This paper presents the results of the effect of fine inert and hydraulic fillers on the early hydration of mortars incorporating these powders. The activity of the mineral additives is assessed by measuring the heat of hydration of the different blended mortars that consist of 90% portland cement and 10% admixture with a 0.45 water-binder ratio (w/b). During the early stages, the fine particles accelerate the hydration rate by providing an increased number of nuclei sites for hydrates growth. These results concern the inert filler (alumina) and the hydraulic or pozzolanic microfillers (ultrafine calcite, silica fume, and quartz powder), or both. At very early stages, the finest particles increase the compressive strength of blended mortars compared with control mortar. Moreover, silica powders, especially silica fume, develop a pozzolanic activity that later increases the compressive strength.