Combining internal and external curing to improve quality of self-compacting concrete with consideration of climate effects

Self-compacting concrete used in reinforced concrete structures with high reinforcement ratios such as ports, tall buildings and bridges can bring benefits to the structures. However, the quality of self-compacting concrete is affected by climate conditions and curing methods. Climate conditions are dry and rainy seasons. Curing methods include external and internal curing. External curing by covering the surface of specimens with nylon sheet for zero hour, 4h, 6h and 24h was investigated in this study. Different amounts of lightweight sand to be able to hold water for internal curing were also examined. Results showed that with the combination of internal curing by using 20% lightweight sand to replace traditional sand and external curing by covering with nylon sheet for 24 hours, the compressive strength of self-compacting concrete in the dry season condition is higher than that of self-compacting concrete without lightweight sand ideally cured by soaking under water at laboratory condition.