COMBINED EFFECTS OF INTERNAL CURING, SLAG, AND SILICA FUME ON DRYING SHRINKAGE OF CONCRETE

Abstract

This study evaluated drying shrinkage of concrete mixtures containing different replacement levels of total aggregate with pre-wetted lightweight aggregate (0, 8, and 10% by volume), replacements of cement with Grade 100 slag cement (0 and 30% by volume), and replacements of cement with silica fume (0, 3, and 6% by volume). The internal curing water provided by pre-wetted LWA ranged from 5.7 to 7.5% by weight (mass) of cementitious material. The mixtures had watercementitious material ratios of 0.44 or 0.45 and paste contents between 23.36 and 24.06% by volume. The results show that internal curing provided by pre-wetted LWA reduces both earlyage (0 to 30 days) and long-term (30 to 365 days) shrinkage. Shrinkage is reduced further as slag is added in conjunction with LWA. An additional reduction in shrinkage is observed as silica fume is added in conjunction with the LWA and slag.