Strength of concrete containing rice husk ash subjected to sodium sulfate solution via wetting and drying cyclic

The influences of different replacement levels of rice husk ash (RHA) blended cement concrete subjected to 5% Na2SO4 solution via wetting-drying cycles was evaluated in this study. RHA was used as a Portland cement Type I replacement at the levels of 0%, 10%, 20, 30%, and 40% by weight of binder. The water-to-binder ratio was 0.49 to produce concrete having target strength of 40 MPa at 28 days. The performance of RHA blended cement concrete on compressive strength, reduction in strength and loss of weight was monitored for up to 6 months. The results of the compressive strength test have been shown that use of RHA in blended cement has a significant influence on sulfate concentration. When increasing the replacement level of RHA, the strength of concrete also increases in comparison to OPC concrete (except RHA40) even exposed to 5% Na2SO4 solution. On the other hand, the reduction in strength and weight loss of specimens increased with increase in the exposure time. Generally, it can be said that the incorporation of rice husk ash as cement replacement significantly improved the resistance to sulfate penetration of concrete. Finally, RHA cement replacement in concrete mixed provided better resistance to sodium sulfate attack up to 6-month exposure