Influence of silica fume replacement of cement on expansion and drying shrinkage

Abstract

An experimental investigation on the effect of silica fume on expansion of cement and drying shrinkage of mortars is reported. Tests were conducted on cylindrical specimens of 30 mm diameter and 30 mm height for expansion of cement pastes. The drying shrinkage of mortars was studied on bars of 25 mm square cross-section and 250 mm length. The variables of the study were percentage replacements of cement with silica fume. The test results indicate that the expansion of cement pastes with the incorporation of silica fume was less than in the ones without silica fume. The 28-day drying shrinkage of mortar bars increases as does the percentage of silica fume, whereas the shrinkage of mortar bars at 405 days for all replacements of silica fume was observed to be about 2.65 ± 0.11%. The addition of silica fume has no significant effect on the long-term drying shrinkage of the mortar. In this study silica fume was used as partial replacement of cement. The silica fume was varied from 0 to 30% by weight of cement.