Effects of elevated temperatures and re-curing on concrete containing rice husk ash

The novelty of this study lies in investigating the effects of elevated temperatures and re-curing on rice husk ash concrete. Concrete specimens were exposed to temperatures 300, 500, and 700 degrees C and underwent water recuring. The mechanical behavior was then analyzed, including compressive strength, elastic modulus and energy absorption capacity. The microstructurals of these specimens were studied under various conditions. The most pronounced degradation occurred at 700 degrees C; the average reduction in compressive strength and elastic modulus of the specimens was 42 % and 79 %, respectively. The concrete specimens containing RHA had better mechanical performance at elevated temperatures than ordinary Portland concrete. The duration of water recuring enhanced the behavior of concrete. The specimens' recovery of strength and modulus of elasticity at all examined temperatures ranged between 8 % and 36 % and 10 % and 85 %, respectively. Models were constructed to predict the stress-strain curves of RHA concrete under elevated temperatures, including its mechanical properties. Finally, the response surface method (RSM) was used to determine the optimal design parameters.