Prediction of optimum compressive strength of light-weight concrete containing Nigerian palm kernel shells

Palm kernel shells (PKS) are vast agricultural by-products that possess silica and alumina minerals in Nigeria. The use of PKS as aggregates has not been standardized for public use, hence, there is need for the prediction and optimization through trial mixes. A target mix was calculated based on American Concrete Institute, ACI code using PKS laboratory properties. Subsequently, factorial design was used to refine mix proportions with additional fourteen mix designs through the means of central composite design. This study employed response surface methodology to design constituent mix proportions and afterward predicted respective values of their compressive strength. The effect of each mix proportion was investigated for fresh and hardened properties of light-weight palm kernel shell concrete (LWPKSC). In addition, the optimal compressive strength of concrete was predicted at 22.24 MPa and realized experimentally at 21.10 MPa. The mix proportion ratio was found to be 1:3.33:1:27 at water-cement ratio of 0.50 with an oven-dry density less than 2000 kg/m 3 . Finally, analysis of variance, (ANOVA) of the results showed that optimum compressive strength of the concrete could be predicted and reliable. </p