Aggregate blending optimisation in quarries to improve of the mechanical and environmental properties of concrete

In this study, concrete mix optimisation was carried out with materials provided by Catalca (Ca) and Cendere (Ce) quarries in the region of Istanbul, Turkey which produce concrete aggregate from different rock formations. Accordingly, the properties of six different concrete aggregates produced from these quarries (3 regions in Catalca quarry and 3 regions in Cendere quarry) and the amounts of CO₂-e released into the atmosphere by producing these aggregates were determined. Then, these aggregates were used in different proportions in concrete mixtures and the effects of aggregate types on the mechanical properties of concrete were statistically demonstrated by the experimental design method. According to the results, the mechanical properties of concrete were statistically significantly affected by the use of aggregate in different formations. In addition, empirical approaches that can be used in estimating the compressive strength, tensile strength and elasticity modulus of concrete have been found and using these approaches, mixtures that maximise these mechanical properties of concrete have been determined. Accordingly, mechanical properties of concrete were maximised in mixtures where Ca 1^st Region 25% - Ca 2^nd Region 75%, Ca 1^st Region 60% - Ca 3^rd Region 40%, Ca 2^nd Region 13% - Ca 3^rd Region 87%, Ce 1^st Region 10% - Ce 3^rd Region 90%, Ce 1^st Region 63% - Ca 2^nd Region 37%, and Ca 1^st Region 35% - Ca 2^nd Region 5% - Ca 3^rd Region 60% were used. The CO₂-e values of these mixtures were calculated as 8.405, 8.248, 8.529, 8.630, 8.476, and 8.365 kg/t respectively.