Strength properties of concrete containing palm bunch ash–calcined anthill clay

Abstract This study evaluated the strength properties of concrete produced with palm bunch ash–calcined anthill clay (PBA-CAC) as pozzolans. Two groups of palm bunch ashes were produced: ashes generated by burning only palm bunches (PBA) and ashes obtained by blending palm bunches and anthill clay at elevated temperatures (PBA-CAC). The PBA and PBA-CAC satisfied the requirements of Class C pozzolans. The concrete constituents were batched by mass, and the cement–fine aggregate–coarse aggregate ratio was 1:2:4. The cement content was partially substituted with PBA and PBA-CAC at 5%, 10%, 15%, 20%, and 25%, with the 0% specimen serving as the control. The concrete cubes were cured for 7, 14, 28, 56, and 90 days, whereas the concrete cylinders and beams were cured for 7, 28, 56, and 90 days. The 28th day strength values of the control specimens exceeded those of the PBA and PBA-CAC concrete specimens. By the 90th day of curing, the strength values of the specimens produced with 5% PBA and 5% PBA-CAC exceeded those of the control specimen. The PBA-CAC specimens generally had higher values of compressive strength, splitting tensile strength, and flexural strength than PBA specimens containing the same amount of pozzolan.