Evaluation of the physical properties of local wheat husk ash and its effects on the compressive strength of hardened cement paste

The dehusking of wheat results in the significant annual production of wheat husk, an agricultural byproduct. This waste is often burned outdoors to generate energy, with the resulting ash (wheat husk ash, WHA) typically disposed of in landfills, leading to environmental harm. To mitigate the negative environmental impact, this research explores the potential of utilizing wheat husk ash to enhance the mechanical properties of cement paste. The study involved the partial replacement of Portland cement in the mixture with varying proportions of wheat husk ash (0, 5, 10, 15, 20, 25 and 30%) to produce WHA blended cement with sample with 0% as the control, and examined the compressive strength of hardened cement paste (HCP) at different curing ages (3, 7, 14, and 28 days). Chemical water tests revealed that the water-to-cement ratio required for standard HCP increased linearly with the proportion of WHA in the mix. Additionally, it was found that the bulk density of HCP decreased as the percentage of WHA increased. Compressive strength tests of the HCP samples yielded promising results, particularly with 15% (30.04) and 20% (28.73) WHA replacement. The compressive strength improved by approximately 14% with 15% WHA replacement and by 10% with 20% WHA replacement. In conclusion, the incorporation of wheat husk ash (WHA) at optimal percentages in cement mixtures enhances the compressive strength of hardened cement paste, particularly after full curing. This study highlights not only the mechanical improvements achieved through WHA integration but also its potential to significantly reduce the carbon footprint of cement production, demonstrating a dual advantage of improved material performance and environmental sustainability.