Substitution by Mass and Volume of a Natural Aggregate with Recycled Concrete Aggregate in an Asphalt Mixture

Abstract

The foregoing article shows a study that had the main goal of evaluating the influence effect of substituting by mass and volume, natural aggregate (NA) of a hot mix asphalt (HMA) with recycled concrete aggregate (RCA). It specifically seeks to evaluate the influence this has on design, volumetric composition of mix and on mechanical resistance under monotonic load evaluated through the Marshall test. A better response can be observed in mixes in terms of resistance and optimum asphalt content (OAC) obtention when substitution of NA with RCA is done by volume. In terms of mix design, the HMA can use RCA as a substitute by mass of the coarse fraction of NA in roadways with low transit volume, increasing in 0.5% the OAC with relation to the control mix (100% NA), while the total substitution of aggregate would require an increase of 0.8%. When substituting the coarse fraction of NA with RCA by volume, the HMA mix can be used in roadways with high transit volumes by increasing the OAC in 0.3% with relation to the control mix, and the total aggregate substitution would require an increase of 0.5% in order to be used in roadways with low and medium transit volumes.