Characterization of Recycled Concrete Aggregate as Potential Replacement of Natural Aggregate in Asphalt Pavement

Abstract

The Construction Industry around the world generates the largest amount of waste and uses generally tons of non-renewable natural resources. Recently, the use of Construction Waste and Demolition (C&WD) in different construction fields has been reported by different authors as its composition includes a wide range of materials. One example of C&WD with potential use in Pavement Infrastructure is Recycled Concrete Aggregate (RCA). RCA have been studied as suitable replacement to Natural Aggregates (NA) in asphalt pavement, results have shown good performance and important environmental and economic benefits from the use of RCA with respect to conventional aggregates. This paper aims to evaluate the feasibility of using RCA obtained from different resources as a replacement material to NA in asphalt concrete mixtures. NA from regional representative quarries were used in this investigation. Instead, RCA was obtained from two different sources; one source, was obtained from a concrete pavement demolition project (Recycled Concrete Aggregate Pavement source-RCAP), and the second source was obtained from the demolition of some concrete structures in a baseball stadium in Barranquilla’s city (Recycled Concrete Aggregate Building source – RCAB). Characterization of both RCA and NA includes determination of physical, mechanical and chemical properties according to Colombian Standards. Laboratory test results indicates that RCA could be a viable option as potential replacement of natural aggregate in asphalt pavement and to reduce the carbon footprint during the production of asphalt mixtures. Nevertheless, some intrinsic properties of the material must be considered with special care, e.g. absorption, gradation, abrasion resistance, pH, among others. Finally, scanning electron microscope (SEM) techniques were used to provide images on RCA’s surface morphology and its composition, giving significant differences between RCA and NA.