Effect of initial and final curing on performance of concrete in hot and arid climates

The effect of initial and final curing conditions of ordinary concrete cast in regions with harsh environmental conditions on the compressive strength and microstructure of concrete is investigated in this research. More than 100 concrete specimens were cast and tested to study the effect of different parameters such as initial curing conditions, final curing durations, outdoor sun exposure, and casting conditions. The results reflect the crucial of the nurturing of concrete after casting in the first 48 hr (initial curing) in increasing its compressive strength, no matter which environment the concrete is exposed to in the later stages of its life. The compressive strength of concrete decreased with decreasing the final curing period regardless of the exposure condition. The degradation in the strength was higher in the case of sun exposure than that of Lab exposure. The maximum degradation in the compressive strength of concrete specimens due to the combined effect of adverse initial and final curing conditions reach up to 68% in the case of outdoor initial curing and zero-day final moist curing. Scanning electron microscopy images and chemical analysis indicate that excessive amount of well-formed and dense clusters of CSH was formulated as the moist curing duration increases.