Optimization and Characterization of Concrete Properties Blended with Sesame Straw Ash as a Partial Replacement of Cement by Response Surface Methodology

Abstract

To encourage sustainable development, it is crucial to explore alternative materials from agricultural or industrial sources that can reduce construction expenses and improve concrete strength. The disposal methods for these agricultural by-products pose environmental challenges. This research focuses on utilizing agricultural waste ash, specifically Sesame straw ash (SSA), as a partial replacement for cement in creating eco-friendly concrete. The study investigated the effects of Sesame straw ash (SSA) on concrete with substitutions of 0, 5, 10, 15, 20, and 25 % relative to the cement weight. The compressive, splitting tensile, and flexural strengths were assessed, along with the workability of concrete with varying SSA proportions. Results showed that adding SSA decreases the workability and strengths of concrete. However, it was noted that the strengths of SSA-modified concrete generally improve with longer curing time. The discrepancy between the predicted and actual values for all responses was found to be under 5 %, demonstrating excellent correlation between predicted and real results in optimal mixing configurations. The ideal mix of 0 % SSA and a curing age of 90 days achieved the maximum compressive strength of 28.294 MPa and a splitting tensile strength of 3.949 MPa and flexural strength of 3.99 MPa. It was concluded that the developed models were suitable for estimating the strengths of the concrete.