Strength of slag-cement concrete cured in place and in other conditions

Slag (ground-granulated blast-furnace slag) blended cements are beneficial in high-strength concrete for reducing hydration temperatures that are a problem in concretes with high cement contents. However; strength development of slag cement is highly sensitive to curing conditions. This paper reports the strength development of 16 full-scale columns containing 0 to 70% slag as the binder with compressive strengths ranging from 40 to tao MPa. The compressive strengths were evaluated by securing cores in the columns. Further, the influences of curing temperature and moisture availability were systematically studied by subjecting standard cylinder specimens to temperature-matched and sealed curing conditions. Altogether; 1250 specimens were tested, 800 of which were cores. The study shows that the in-place strength of the concrete with slag blends is significantly less than the standard-cured cylinders. Also, sealed curing is the most representative of the in-place curing conditions when compared with temperature-matched curing and standard curing conditions.