Chemical shrinkage of cement pastes and mortars at very early age: Effect of limestone filler and granular inclusions

This article presents a study on the influence of limestone filler and granular inclusions on the chemical shrinkage of cementitious matrices at very early age (<= 24 h). Measurements of chemical shrinkage and hydration degree are carried out on cement pastes and mortars. During this study, two cement types (CEM 1 and CEM 2), two water-to-cement ratios (W/C = 0.30 and 0.40) and three substitution rates of cement by limestone filler (LF/C = 0; 0.25 and 0.67) are used. The effects of aggregate shape (glass beads and natural sand), aggregate-to-cement mass ratio (A/C = 0.5 and 1) and particle size distribution (D = I and 2 mm) on the chemical shrinkage and the hydration rate are quantified. The results obtained show that limestone filler causes an acceleration of both Le Chatelier's contraction and hydration process since the very first hours of hydration. In addition, the chemical shrinkage amplitude is not significantly influenced by the presence of aggregates. Finally, the presence of limestone filler and granular inclusions does not cause significant modification of the quasi-linear relation observed at early age between the chemical shrinkage and the hydration degree of the cementitious matrices. (c) 2007 Elsevier Ltd. All rights reserved.