Evaluation of Corn Cob Ash as Partial Replacement of Cement in Sandcrete Bricks

This study investigates the utilization of corn cob ash as a partial replacement for cement in the production of sandcrete bricks. This was necessitated due to the high cost of cement and the eco-friendly alternative to cement potentials the corn cob ash may possess. The corn cob was obtained from locals in Uselu, Benin City and was washed, dried for 24 hours then burnt in the furnace at 700 °C for 12 hours to obtain the ash at Engineering Faculty Workshop, University of Benin, Benin City. The corn cob ash substitution with cement, were done in weighted percentages, between 10 % and 20 %, cured for 3 days, 16 days and 28 days in a laboratory controlled environment using varying water/cement ratios and fine aggregates. Response surface methodology in Design- Expert 7.0 software was used to produce the experimental designs. The results obtained, reveal that corn cob ash can replace cement, up to 10 % weighted percentages in sandcrete brick, without reducing its compressive strength below 2.5 N/mm 2 and it also had 11.98 % of water absorption, which satisfied the standards for non-load bearing sandcrete bricks. The quadratic model formulated for the blended sandcrete brick was significant possessing a p-value of 0.02 and 0.047 with an adjusted R 2 value of 0.65 and 0.56 for the compressive strengths and water absorption properties respectively.