Concrete Mix Process Optimization Using Full Factorial Design

A full factorial design was employed to obtain optimum target concrete mixtures strength using data obtained through full experimental design from Central Bank of Nigeria (CBN) Abeokuta Renovation Project, Ogun state (2014). The factors were four; water, cement, fine aggregate and coarse aggregate. The factors had three levels each which were in volume fraction ranges, designated as low, medium and high. A total of 81 concrete mixtures with three replicates (243 specimens) were considered by varying the levels of the factors affecting strength of concrete. The data obtained from these 243 specimens was analysed using plots analyses, factors effect plots, residual analyses and analysis of variance. Also, a regression model for concrete strength with its parameters was estimated. From the model and the estimated parameters, it was shown that the factor-level combinations that gave the optimum approximation of the target strength of concrete (28.00N/mm2) was water at low (0.14), cement at high (0.15), fine aggregate (0.30) and coarse aggregate at low (0.38) levels.