Influence of Calcium Chloride on the Drying Shrinkage of Alite Paste

Abstract The drying shrinkage at 55% relative humidity of alite pastes with and without 1% calcium chloride (CaCl2) at equal degrees of hydration was investigated. CaCl2 increases drying shrinkage at all levels of hydration studied. However, the difference in drying shrinkage of pastes with and without 1% CaCl2 decreased with increased hydration. Shrinkage of pastes with CaCl2 decreased with increasing hydration (40 to 75%), whereas shrinkage of pastes without CaCl2 increased with increasing hydration (43 to 62%). A larger weight loss during drying was noted in pastes without CaCl2. Reference is made to the relationship between the observed shrinkage in alite pastes and differences in the pore size distributions of tricalcium silicate pastes with and without CaCl2.