The global construction industry is increasingly seeking sustainable alternatives to Ordinary Portland Cement (OPC) to mitigate carbon dioxide emissions associated with its production. In Vietnam, a leading global rice exporter, the disposal of rice husk presents a significant environmental challenge, as it is often burned in open fields. This study investigates the utilization of Rice Husk Ash (RHA) as a Supplementary Cementitious Material (SCM) in the production of High-Strength Concrete (HSC). The experimental investigation involved replacing OPC with processed RHA at substitution levels of 0%, 5%, 10%, 15%, and 20% by weight, with a specific target compressive strength exceeding 60 MPa. Mechanical properties and durability were assessed through compressive strength testing and rapid chloride permeability tests. The results demonstrate that RHA possesses high pozzolanic reactivity, effectively refining the pore structure of the concrete matrix through the formation of additional calcium silicate hydrate (C-S-H) gel. The comparative analysis reveals that a replacement level of 10% to 15% is optimal, achieving maximum compressive strength and significantly improved resistance to chloride penetration compared to the control mix. The study concludes that utilizing RHA in HSC production is a viable strategy for the Vietnamese construction sector, offering a sustainable solution that addresses both agricultural waste management issues and the demand for high-performance building materials.
Keywords: Rice Husk Ash; High-Strength Concrete; Supplementary Cementitious Materials; Pozzolanic activity; Sustainable construction; Chloride resistance.