Effect of high-temperature curing duration on the compressive strength of concrete

Abstract

Concrete is an important construction material in civil engineering due to its strength and durability. However, its mechanical properties may be altered when exposed to high temperatures, particularly those related to coarse aggregates. The use of limestone aggregate could result in a reduction in compressive strength and the formation of cracks, whereas basalt aggregate with its high density and superior heat resistance, has the potential to enhance concrete strength. This research investigated the effect of high-temperature curing duration on the compressive strength of concrete using basalt as coarse aggregate. Cube-shaped concrete specimens (15×15×15cm) were tested at ages of 1, 3, 7, 14, 28, and 56 days under curing at ambient temperature (25°C) and high-temperature curing at 100°C for 3 and 6 hours, with a controlled water-to-cement ratio of 0.45 and coarse aggregate sizes of 3/4, 1/2, and 3/8 inch. The results showed that basalt aggregate consistently provided higher compressive strength than limestone aggregate under all curing conditions, especially at ages of 7 and 28 days with the compressive strength increased 10-22%, which an increasing of 10-18% and 15-22%, respectively. This enhancement was attributed to accelerated cement hydration at elevated temperatures and the superior strength and thermal resistance of basalt aggregate. The findings indicated that basalt aggregate is suitable for the design of early-age high-strength concrete in high-temperature environments.