Effects of cow bone ash as a partial replacement of cement in the production of concrete

Abstract The demand for cement in the production of concrete is on the increase and its production is accompanied with the emission greenhouse gases resulting into global warming. Cow bones are being dumped into landfills thereby causing environmental pollution. This study aimed at investigating the use of cow bone ash (CBA) as a partial replacement of cement in concrete. The bones were propely cleaned of dirt and calcinated in a furnace at a temperature of 900℃. The ash was characterized to determine its elemental oxide compositions, and used to replace cement in 0, 5, 10, and 20%, respectively. Concrete proportioning of 1:2:4 and water-binder ratio of 0.5 were adopted. The workability of the concrete was investigated and thereafter, cast in moulds of 100 mm cubes and cured in water for 7, 14, 28, and 56 days, respectively. A total of 48 cubes were cast and the compressive strength was evaluated at corresponding curing ages. The results of characterization revealed that the CBA exhibited more of calcereous compounds and Hydroxyapatite with supplementary cementitious property owing to the presence of silica, ferric and alumina. The slump decreased with increasing content of CBA. In addition, the compressive strength was observed to reduce with increasing CBA. However, at later age of curing, the compressive strength of concrete with 5% CBA surpassed all levels of replacement. This is an evidence of pozzolanic potential being exhibited by the CBA. Futhermore, the least water absorption was observed with 5% CBA. In conclusion, the incoporation of 5% CBA enhanced the compressive strength of the concrete and could be recommended for structural works.