Abstract Manager

Reducing waste and conserving natural resources are the main reasons for using recycled concrete aggregate (RCA) in concrete pavement. Concrete reuse helps the construction sector reduce the need for virgin aggregate, lessening quarrying operations and the related environmental effects, like dust production and habitat destruction. Supplementary cementitious materials (SCMs) significantly reduce CO2 emissions and cement usage in concrete mixes. Substituting crushed RCA for natural aggregates (Nag) and SCMs for conventional cement can achieve a more sustainable concrete production method. This method is a greener option because it reduces the environmental impact of concrete and helps protect natural resources.

This study aims to examine the durability and mechanical characteristics of concrete mixes designed for interlocking concrete pavers that contain SCMs and coarse recycled concrete aggregates (CRCA). The research evaluates the feasibility of incorporating environmentally sustainable materials into traditional concrete production, focusing on shear strength and splitting tensile strength. Three concrete mixes with different proportions of CRCA and SCMs (0%, 20%, and 40%) and (0%, 20%, and 30%) are evaluated against the control mix. Ground glass pozzolans (GP), limestone cement (GUL), and slag were used as SCMs in this study. The specimens were tested after 28 days of curing.

The outcome indicated that the control mix (CM) had the highest shear strength value compared to the other mixes. As the percentage of CRCA in mixtures increased, the shear strength value dropped by as much as 20.27%. However, when the replacement percentage of CRCA was 20%, there was a slight variation in the shear strength value of less than 1%. In addition, the splitting tensile strength value was highest for CM. The splitting tensile strength value dropped by 14.5% as the CRCA replacement percentage up to 40%. The mixes with the lowest value were RC 40/S 20/G 10. The difference in tensile strength was less than 1% when the CRCA replacement percentage was 20%. Furthermore, the results demonstrate that adding SCMs had no discernible impact on the concrete's shear and splitting tensile strengths. Consequently, the results support using CRCA up to 20% as a partial substitute for NAg in interlocking concrete paving (ICPs) to lower natural aggregate consumption and serve as a step towards more sustainable concrete construction.

Keywords: Coarse recycled concrete aggregate (CRCA), Supplementary cementitious materials (SCMs), Slag, Ground Glass Pozzolans (GP), Limestone Cement (GUL), Sustainable concrete, Shear and tensile strength