Use of concrete fine fraction waste as a replacement of Portland cement

Abstract

This work aims to evaluate the use of fine fraction of concrete waste (CW) from construction and demolition waste (CDW) as a replacement for Ordinary Portland cement (OPC) in production of composites. Therefore, the CW was mechanically treated (crushing and sifting) and characterized regarding its granulometry, chemical and mineralogical composition (XRF and XRD) and pozzolanic activity (PAI). The CW fraction used consists of particles with a diameter below 0.15 mm. Mortar specimens with different CW granulometry and replacement content (0%, 15%, 25% and 50%) were produced to test their compressive strength. Also, studies of compressive strength, elasticity modulus, tensile strength and SEM/EDS were carried out in concrete specimens with different replacement content (0%, 15% and 25%). Results show that the studied material has compatible characteristics with Portland cement and can be used in replacement contents up to 25% in mortars and concretes. Furthermore, there were not discrepant changes in elasticity modulus, tensile strength and micrography of concretes, which indicates a potential use of CW as an environmentally friendly alternative in the production of eco-efficient cement.