Mechanical Behavior of Fine RHA Concrete

Abstract

This research was aimed to investigate the effect of high fineness rice husk ash (FineRHA) on mechanical behavior of fine RHA concrete as compared to ordinary Portland cement concrete (OPC). The properties to be investigated included slump, unit weight, compressive strength, modulus of elasticity and temperature of hydration. The fine RHA replacements were varied from 0%, 20% and 40% by weight of binder. The ratios of the volume of paste to volume of minimum voids content of total aggregates (g) were 1.2, 1.4 and 1.6. The water to binder ratios were 0.5, 0.6 and 0.7.

The results indicated that fine RHA has a highly pozzolanic reactivity and can be used as a supplementary cementitious material in concrete. Slump of fine RHA concrete was lower than OPC concrete, but higher than that of RHA044 (RHA with average diameter 44 mm) concrete. For the same mixture, the unit weight of fine RHA concrete decreased when RHA replacements were increased. It was also found that the compressive strength after 28 days of fine RHA concrete was higher than OPC at w/b equal to 0.5 and 0.6 especially for fine RHA replacement equal to 20%. The modulus of elasticity of fine RHA concrete was slightly lower than OPC concrete. The temperature of hydration of fine RHA concrete was lower than that of OPC concrete in every mixtures.