Prediction of Compressive strength of Periwinkle Shell Aggregate Concrete Using a Quadratic Polynomial Function

Abstract

In this study, a mathematical model is developed to predict the compressive strength of normal concrete made with periwinkle shell as coarse aggregate using a quadratic polynomial function. The response function is expressed as a multivariable function of the proportions of the component materials (water, ordinary Portland cement, sand and periwinkle shell). A total of thirty experimental runs were used to demonstrate the applicability of the mathematical model developed. The first ten mix ratios were used to develop the model while the remaining twenty mix ratios were used as check points to validate the model. Both the measured and predicted values were found to coincide at all points of observation. The model was tested for reliability at 95% level of confidence using Student’s t test and was found to be adequate. A visual basic program was developed based on the model was invoked to speed up the selection of the mix ratios of the component materials corresponding to the desired compressive strength value and vice versa.

Keywords: Mathematic model, Compressive strength, Quadratic polynomial function, Periwinkle shell, Multivariable function, Mix proportions