Sustainable selection of the concrete incorporating recycled tire aggregate to be used as medium to low strength material

Many studies have been conducted on the mechanical properties of concrete incorporating recycled tire aggregate. The present work has the same theme with two clear distinctions: First, a vast majority of past experiments were conducted on concretes with compressive strengths in the range between 30 and 60 MPa. In the present work, concretes with compressive strength values below 20 MPa were designed and prepared in the laboratory by replacing conventional aggregates by recycled tire aggregates with an amount of 10, 20 and 30% by volume. Compressive strength was measured up till 90 days and results showed that replacing a small portion of natural fine aggregate with a finer rubber aggregate increased the 90 days compressive strength of concrete by 12%, possibly due to the resulted densification of the fine aggregate. All the past studies concluded that using rubber aggregate reduces the compressive strength of concrete. Based on the statistical analyses of the results from the past studies and the present work, a relationship with high accuracy was developed to predict the compressive strength of concrete incorporating fine rubber aggregate. Secondly, the environmental performance of rubberized concrete was also evaluated by assessing two environmental impact indicators; CO2 footprints and volume utilization of raw materials. Finally, an analytical framework was developed for the sustainable selection of rubberized concrete by incorporating mechanical and environmental performance. Two multi-criteria decision-making techniques were used to select the best ideal solution in favor of rubberized concrete as a structural material and medium to low strength material. The great potential of using rubber content in concrete as a medium to low strength material was observed.