Effect of Chlorides and Curing Duration on the Hydration and Strength Development of Plain and Slag Blended Cements

摘要

This study investigated the effect of chloride ingress on the hydration mechanism and strength development of plain and slag blended cements. The slag blends were prepared by combining two slags with a CEM I 52.5R-type cement at 30%wt. replacement, while a CEM I 42.5R-type cement was selected as the plain cement. Mortar and paste samples were prepared using a water/binder ratio of 0.5. These were subjected to three different curing regimes - control, 7 and 28 days control curing followed by curing by immersion in a 3% NaCl solution, and tested for compressive strength and hydration using TGA and XRD. Results showed that chloride ingress accelerated the early hydration up to 28 days, and decelerated the later hydration. This effect was more pronounced on samples that were cured for shorter durations before exposure. The slag blends had better strength performance than the plain cement in all curing and exposure conditions.