Comparative Study on Rice Husk Ash and Silica Fume as Supplementary Cementitious Material in High Performance Concrete Production

Abstract

High-Performance Concrete (HPC) utilisation is gaining wide acceptance across the globe due to its high strength, elastic modulus, durability properties and economy. The production process however, requires incorporation of supplementary cementitious materials (SCMs) with Silica fume (SF) mentioned in literature as most adopted. Non-availability of silica fume in the sub-Sahara African countries has necessitated search for local alternative SCMs for HPC production of which Rice husk ash (RHA) has been found readily available with little or no attempt to benchmark its performance level with silica fume. This article thereby reports on a study conducted to establish the comparative effectiveness of Nigeria’s RHA as an alternative to SF in HPC production for the development of a sustainable built environment in the era of pandemic. It further examines the effect of pre-soaked pumice in comparison to superabsorbent polymer (SAP) as internal curing (IC) agent on compressive strength of the HPCs. HPC mixes of varied RHA contents (5, 10 and 15% by weight of binder (bwob)) were studied and examined for compressive strength in comparison with HPC mix of 7.5% bwob SF content. The IC-agents were kept constant (SAP at 0.2% bwob and pre-soaked pumice at 5% by weight of coarse aggregate (bwoca) respectively) for this experiment. The HPC specimen were immersed in water bath for 28 days of curing before testing for compressive strength. The results reveal C3 (i.e., 5%RHA based-HPC specimen with SAP as IC-agent at 0.2%bwob) had compressive strength value slightly higher (i.e., 0.13%) than the control specimen – C0 (7.5%SF based-HPC with similar SAP content).