Evaluation of Groundnut Shell Ash as a Supplementary Cementitious Material in Concrete Production in Kano State

This study evaluates the pozzolanic potential of groundnut shell ash (GSA) as a supplementary cementitious material in concrete production, using locally sourced material from Kano State, North West Nigeria. The annual generation of large quantities of groundnut shell waste in northern Nigeria presents both an environmental management challenge and a potential raw material resource for the construction industry. Groundnut shells are incinerated in a controlled furnace at temperatures of 600, 700, and 800 degrees Celsius, and the resultant ash is characterised for chemical composition, loss on ignition, and fineness using XRF and BET analysis. GSA is incorporated as a partial replacement for ordinary Portland cement at 0, 5, 10, 15, and 20 percent by weight. Concrete cube specimens are produced and tested for compressive strength, setting time, and water absorption at 7, 28, and 56 days. Results indicate that GSA calcined at 700 degrees Celsius exhibits the highest silica content and pozzolanic activity index. Compressive strength is maintained at acceptable levels up to 10 percent GSA replacement, reaching 96 percent of control strength at 28 days. Setting time increases moderately with GSA addition. The study concludes that GSA calcined under optimised conditions can partially substitute OPC in non-structural concrete applications, reducing both cement consumption and agricultural waste. Keywords: groundnut shell ash, pozzolan, supplementary cementitious material, concrete, Kano State.