INFLUENCE OF SORGHUM HUSK ASH AS A MICRO-FILLER IN POLYMER CONCRETE

This research investigated the potential of ground sorghum husk ash (GSHA) as a sustainable micro-filler in epoxy-based polymer concrete through partial replacement of conventional stone dust. Three mix proportions were prepared: a control mix (0 % GSHA) and two modified mixes containing 10 % and 20 % GSHA by weight of total filler. Epoxy resin content was maintained at 12 % in all mixes, while fine aggregate, coarse aggregate, and stone dust proportions were adjusted accordingly. Workability was evaluated using a modified slump test (BS 1881-102:1983), and 150 mm cubes were cast and cured at ambient temperature for 28 days. Compressive strength was determined in accordance with BS 6319-3:1990. Results revealed that increasing GSHA content reduced workability (flow diameter decreased from 475 mm to 280 mm) and slightly lowered hardened density (2429 kg/m³ to 2341 kg/m³) due to the lower specific gravity and higher absorption capacity of the ash. However, compressive strength was significantly enhanced: the control mix achieved 30.0 N/mm², while the 10 % and 20 % GSHA mixes recorded 36.4 N/mm² (+21.3 %) and 34.0 N/mm² (+13.3 %) respectively. The optimum replacement level was therefore identified as 10 %. The study concludes that properly processed sorghum husk ash is an effective, low-cost, and environmentally friendly micro-filler that improves the mechanical performance of epoxy polymer concrete. Its adoption will promote agricultural waste valorisation, reduce reliance on quarried materials, and support sustainable construction practices in Nigeria.