Effectiveness of Rice (Oryza sativa) Hull Ash (RHA) as Partial Replacement of Cement in Concrete Exposed in Coastal Conditions

Cement use and production are among the largest contributors to greenhouse gases. Thus, we endeavor to utilize agricultural wastes to reduce the consumption of cement while improving the properties of the concrete. This study aimed to determine the effect of rice hull ash (RHA), as partial cement replacement, on concrete's workability, permeability, and compressive strength. Also, it aimed to compare the changes in compressive strength before and after exposure to coastal conditions and perform a cost analysis of concrete mixtures. This experiment used three different RHA loadings (5%, 10%, 15%) as partial replacement to cement. This study concludes that replacing cement with RHA resulted in low workability and lower chloride penetration. Also, replacing cement of up to 10% RHA has comparable compressive strength with pure concrete before exposure to coastal conditions. Replacing up to 15% of RHA has comparable compressive strength with pure concrete after exposure to coastal conditions. Using RHA replacement has a lower production cost than pure concrete.