Amoyen, Jinggoy M.2026-10-262026-10-262023-05Amoyen, J. M. (2023). Effectiveness of Rice (Oryza sativa) Hull ash (RHA) as partial replacement of cement in the properties of concrete exposed in coastal conditions. [Unpublished Undergraduate Feasibility Study, Don Mariano Marcos Memorial State University - North La Union Campus, Sapilang, Bacnotan, La Union]. Lakasa ti Sirib, DMMMSU Institutional Repository.https://lakasa.dmmmsu.edu.ph/handle/123456789/2852The silica content of the ricehull ash (RHA) gives it the pozzolanic property which makes it a suitable replacement for ordinary Portland cement. This study aimed to determine the effect of 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 treatments (5%, 10%, 15%) level of RHA, a 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 5% 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.en-USRice hull ashCement replacementConcrete propertiesCoastal conditionsSustainable construction materialsAgricultural waste utilizationConcrete durabilityConcreteRice hull ashCementBuilding materialsgricultural wastes as building materialsSustainable constructionThesis