IMPACT OF CONSTRUCTION AND DEMOLITION WASTE ON CONCRETE PRODUCTION: A SUSTAINABILITY APPROACH

Abstract

The utilization of construction and demolition waste is an effective strategy for reducing the environmental impact of the construction sector and promoting the circular economy, with proven application in the manufacture of new concretes. In this field, recycled aggregates obtained from concrete waste, although they present unfavorable physical properties compared to those obtained from rock crushing, can replace the latter under certain conditions. This research evaluates the technical and environmental feasibility of using recycled aggregates to replace those obtained from rock crushing in the manufacture of hydraulic concretes. Through experimental tests of workability, compressive strength, capillary absorption, resistivity, and drying shrinkage, complemented by a life-cycle analysis, mixtures with 20%, 30%, and 40% replacements of recycled concrete aggregates with natural aggregates were analysed. The results showed that a substitution of up to 30% maintains strengths above 26 MPa at 28 days and complies with ASTM and INEN standards, reducing CO₂ emissions by up to 16.7% and energy consumption by 15%. Higher substitution percentages increased porosity and capillary absorption, requiring pretreatments and additives to preserve durability. This approach supports the transition toward more sustainable constructions that rely less on virgin resources.