Strength of Binary Blended Cement Composites Containing Plantain Leaf Ash

Abstract

The strength characteristics of binary blended cement composites made with Ordinary Portland Cement (OPC) and Corn Cob Ash (CCA) were investigated in this work. 105 concrete cubes and 105 sandcrete cubes of 150mm x 150mm x 150mm were produced at percentage OPC replacement with CCA of 5%, 10%, 15%, 20%, and 25% and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The 3-28 day compressive strength values of OPC-CCA binary blended cement concrete were found to be much lower than the control values; the 50 day strengths were comparable to the control values; while the 90 day strengths were higher than the control values especially at 5-15% replacements of OPC with CCA, ranging from 24.00N/mm2 for 15% replacement of OPC to 27.00N/mm2 for 5% replacement of OPC compared with the control value of 23.60N/mm2. This same trend was observed for OPC-CCA binary blended cement sandcrete. The variation in density was not significant. Mathematical models were developed for predicting compressive strengths of OPC-CCA binary blended cement composites using polynomial regression analysis. The model values of compressive strengths obtained from the various model equations were found to be either exactly the same as those of the equivalent laboratory values or very close to them, with differences ranging from 0 to 0.3N/mm2. Thus, OPC-CCA binary blended cement composites could be good for civil engineering works and the developed model equations can be used to estimate their strengths for various curing ages and percentage OPC replacement with CCA.