Effect of recycled concrete aggregate size on physical and mechanical properties of eco-friendly-self-compacting concrete

Abstract

In recent years, the rapid increase in population and building demand across the world leads to significant deterioration or reduction of natural resources. Meanwhile the huge amounts of waste from the demolition of buildings and concrete structures in the landfill space become a serious ecological and environmental problem. The recovery of aggregates from recycled concrete for the formulation of new concrete would contribute to reducing the depletion of natural resources and therefore integrate into the context of sustainable development, because there are several socio-economic advantages. The objective of this possibility of using aggregates from recycled concrete mixes. We have established a comparison between the physical and mechanical behavior of SCC based on RCA (Recycled Sand: SR 0/3 and Recycled Gravel RG: 3/8 and 8/15) and that of SCC based on natural aggregates (NA) on fresh support and hardened state. Additionally, Non-Destructive Testing (NDT) methods were conducted in this research to obtain more information about the properties of the studied SCC. The results of the tests on fresh SCC meet the recommendations of the French Association of Civil Engineering (AFGC). The physical and mechanical behavior of SCC-RS is relatively weak compared to SCC-NA/RG. This is directly related to the high absorption capacity of the aggregates (depending on the size of the aggregates) and the poor quality of the mortar attached to the aggregates, which can create areas of weakness in the concrete structure. From the regression results, it was found that there is a direct correlation between the physical and mechanical properties of different concretes indicated by the higher values of R-squared (R2 = 0.92).