UTILIZATION OF RICE HUSK ASH AS A SUPPLEMENTARY CEMENTITIOUS MATERIAL IN HIGH-STRENGTH CONCRETE: A REVIEW

Abstract

Rice husk ash (RHA) has emerged as a promising sustainable supplementary cementitious material (SCM) for high-strength concrete (HSC) applications due to its high amorphous silica content and environmental benefits. This review synthesizes recent peer-reviewed research on the mechanical properties, durability characteristics, and microstructural behavior of HSC incorporating RHA. The paper evaluates optimal replacement levels, compressive strength development, workability, and long-term performance through systematic analysis of experimental studies published between 2019 and 2026. Key findings indicate that RHA replacements of 5–15% by weight of cement can enhance compressive strength in HSC, with optimal results frequently achieved at 10–15% replacement levels, yielding strengths exceeding 100 MPa at 28 days when properly combined with other pozzolanic materials or nano-silica. Durability assessments reveal significant improvements in chloride ion resistance, water absorption reduction, and reduced permeability with controlled RHA incorporation. The pozzolanic reactivity of RHA, characterized by amorphous SiO₂ content ranging from 69–90%, enables the formation of dense calcium silicate hydrate (C-S-H) gels, enhancing microstructural densification. However, challenges including variable ash composition, porosity development at higher replacement levels, and workability reduction necessitate careful mix optimization. This review identifies research gaps in long-term performance prediction, standardization protocols, and field-scale applications, while emphasizing RHA's potential in advancing sustainable, eco-friendly HSC production aligned with circular economy principles and carbon emission reduction goals