Compressive strength and Scheffe’s optimization of mechanical properties of recycled ceramics tile aggregate concrete

Abstract

Ceramic industry generates a large amount of wastes which are presently not reused in any significant quantity. Reusing these wastes in concrete could solve the ceramic industry waste management problem and also lead to a more sustainable concrete industry. While the use of ceramic wastes as coarse aggregate has been extensively investigated, not much findings are available on its use as fine aggregate and there are presently no models for predicting the properties of ceramic wastes aggregate concretes. This study investigates effect of crushed recycled-ceramic tiles (CRT) fine aggregate content on compressive strength of concrete. Scheffe’s second degree polynomial models were also formulated for compressive strength, slump height and cost of CRT concrete. Results show that incorporation of CRT as fine aggregate improves the compressive strength of concrete and this increase is directly proportional to its content. Authors therefore recommend up to 100% replacement of conventional fine aggregate with CRT in concrete production. The formulated models could predict compressive strength, slump and cost of CRT concrete if the mix ratio is known and vice versa. Analysis of variance and normal probability plots of model residuals were used to test adequacy of the models, and the models were found to be adequate at 95% confidence level. With the model equations, sample optimization was carried out to obtain the most economical mix for certain predefined criteria and the results were promising. Several similar optimizations can be carried out using the formulated model equations for any desired criteria of the modeled responses.