Prediction of Strength Properties of Concrete Containing Calcined Black Cotton Soil Using Response Surface Methodology

Abstract

This research predicts the strength properties of concrete containing Calcined Black Cotton Soil (CBCS) using response surface methodology. Cement production requires large amount of energy and emits greenhouse gases that have negative impact on the environment. Utilization of CBCS as cement replacement in concrete will reduce these negative impact. Experimental plan was designed using response surface method in Design Expert software to predict compressive strength, density and water absorption of concrete containing CBCS. The CBCS was varied from 5 to 20% while the curing period was varied and 7 to 28 days. Face-centered central composite design method of response surface was used. The design consists of two design factors at three levels (coded as -1, 0, +1) each. The factors are the curing period, and the CBCS contents. The results showed that CBCS is a pozzolana. CBCS increases durability of concrete by decreasing its water absorption. All the response surface models developed for the water absorption, density and compressive strength showed very good relationship between the predictors and the responses with coefficients of determination, R² > 0.94 and p-values < 0.05.