Technical analysis of the recycling of construction waste in construction site

Abstract This work aims to technically evaluate the recycling of construction waste from concrete and mortar, generated on a construction site of a large construction company. Subfloor, internal and external coating mortars were analyzed, considering replacement of natural sand by recycled aggregate in the percentages of 25% and 50%. Properties were evaluated in the fresh state (consistency, incorporated air content, mass density), in the hardened state (hardened density, modulus of elasticity, flexural strength, compressive strength) and in the coating mortar (adhesive strength, cracks and water permeability). It was found that the fine content of the recycled aggregates was less than 10%, with no potential impact on cracking. It was also observed an increase in the content of incorporated air with an increase in the content of substitution of natural aggregate for recycled in the mortars of subfloor and external coating mortars, however for the internal coating mortars the behavior was the opposite. Regarding adhesive strength, there was no impact on the replacement content. For compressive and flexural strength, there were significant variations, but all mortars remain in the same classification extract, according to NBR 13281. As far as cracks are concerned, these were reduced by replacing natural sand with recycled aggregate. In terms of water permeability, the results found were considered low for all types of mortars.