Compressive strength and ultrasound pulse velocity of mineral admixtured mortars

Abstract

Ultrasound pulse velocity is used to evaluate the compressive strength of mortar with mineral admixtures. In addition, the relationship between ultrasound velocity and destructive compressive strength are evaluated. Silica fume (SF), fly ash (FA) and blast furnace slag (BFS) are used as mineral admixtures for the replacement of Portland cement (PC) up to 30%, 50% and 70%, respectively, by weight. The maximum compressive strength and ultrasonic pulse velocity (UPV) have been observed with the samples containing BFS. Both compressive strength and UPV are very low for all the levels of mineral admixture at an early age curing, especially for samples containing high volume FA. However, with the increase of curing period both compressive strength and UPV of all the samples are increased. 10% of SF increased both compressive strength and UPV at 7, 28 and 90-day curing period, but the other SF replacement decreased. At 28 and 90-day of curing periods, BFS increased UPV for all levels and increased compressive strength for 10% and 20% BFS replacement. In addition, reductions due to BFS at early ages are decreased for the other level of BFS, even at 28-day of curing period and for 10%, 20%, 30% and 50% increased compressive strength 36%, 24%, 22% and 8%, respectively. The increment in the compressive strength due to curing period is higher than that of UPV. The relationship between UPV and compressive strength is exponential for SF, FA and BFS.