Experimental development of low cement content and recycled construction and demolition waste aggregates concrete

Innovative eco-efficient concrete was developed and characterized, to reduce the environmental impact related to construction and demolition waste, extraction of natural aggregates, and CO2 emissions of Portland cement. Several concrete mixtures with low cement content and incorporating construction and demolition waste (CDW) recycled aggregates, herein named "low cement recycled aggregates concrete" (LCRAC), were newly developed. Characterization tests were performed to minimize cement dosage and maximize the replacement of natural by CDW aggregates. An optimized matrix of low cement concrete was developed and high replacement volume rates of CDW aggregates (43-80%) were considered, leading to different LCRAC, to evaluate their influence on concrete properties. The mechanical properties of LCRAC are highly influenced by the aggregates composition and its replacement rate. A reduced and optimized cement dosage, of 175 kg/m(3), allows producing sustainable LCRAC for structural applications. The strength reduction of LCRAC is limited to only 30% when incorporating high volume of CDW, up to 60%, since the strength loss of CDW is balanced by the matrix high compactness and higher strength, resulting in equivalent strength of ordinary concrete formulation. (C) 2020 Elsevier Ltd. All rights reserved.