Prediction of the Compressive Strength of Aluminum Waste–Cement Concrete Using Scheffe’s Theory

The characterization of aluminum waste (AW) as a supplementary cementitious material (SCM) and its effect on concrete properties were investigated. This paper proposes a model for the prediction of the compressive strength of AW-cement concrete using Scheffe’s theory. The powder (material) derived from aluminum smelting waste obtained from the aluminum extrusion plant, Inyishi, in Ikeduru local government area in Imo State, Nigeria was used in this research as partial replacement for cement in various mix proportions. The compressive strengths predicted by this model agreed with the corresponding experimentally obtained values. The optimum compressive strength of AW-cement concrete predicted by Scheffe’s simplex model is $28.832\mathrm{N}/{\mathrm{mm}}^2$. The density of the resulting AW-cement concrete was not significantly affected by the partial replacement of cement with aluminum waste. The addition of AW decreased both the initial and final setting times. The initial and final setting times for 0% cement replacement were 62 and 532 minutes while the corresponding values for 5, 10, 15, 20, and 30% replacement ranged from 36 to 58 min for the initial and 435 to 518 min for the final setting times. It was also observed that the AW absorbed water from the mix and therefore reduced workability. The model developed was tested for adequacy using $t$-statistic and $f$-statistic tests and were found to be adequate.