Evaluation of Effects of Recycled Concrete Aggregate on Volumetrics of Hot-Mix Asphalt

Abstract

Each year around 200 million tons of demolition wastes are produced from aging U.S. infrastructures. Of that amount, 100 million tons are portland cement concrete debris. Disposal of these wastes in landfills has been a traditional solution, but environmental regulations, costs, and a lack of landfill areas have hindered safe disposal. These problems have led to a search for alternate ways of reusing demolition wastes by recycling. Recycling the concrete waste not only reduces the waste disposal problem but also reduces the quarrying of virgin aggregate. The incorporation of recycled concrete as a hot-mix asphalt (HMA) aggregate can be a viable option in terms of costs and environmental considerations. This use of recycled concrete aggregate (RCA) as an HMA aggregate can be beneficial for constructing low-volume roads. RCA differs from virgin aggregates in that there is cement paste on the surface of the recycled concrete. In this study, 5% RCA was evaluated as an HMA aggregate. Mix designs were conducted, and the effect of RCA on the volumetrics of HMA was evaluated. The mix design results indicated that RCA is absorptive, and that as the percentage of recycled concrete increased in the mix, the optimum asphalt content increased linearly. The statistical regression model showed that RCA had significant effects on the volumetrics of the mix.

Recycled construction and demolition waste in Cold Asphalt Mixtures: evolutionary properties

“…As far as the ecological and financial implications are concerned, CAM can be further improved when produced with 100% recycled materials from Construction and Demolition Waste Aggregates (CDWA 4 ). Research on HMA with recycled aggregates from waste materials has experienced extensive and growing success recently (Bhusal et al, 2011;Chen et al, 2011;Liu et al, 2012;Mills-Beale and You, 2010;Modarres et al, 2015;Paranavithana and Mohajerani, 2006;Pérez et al, 2010;Pérez et al, 2012;Wong et al, 2007), thus reinforcing this new approach within pavement engineering. To a lesser extent, and although more research in this regard is necessary, different studies on CAM with recycled aggregates can also be found at present (Gómez-Meijide and Pérez, 2014b;Gómez-Meijide et al, 2015;Modarres and Ayar, 2014).…”

Feasibility of using recycled concrete aggregates for half-warm mix asphalt

“…Most studies agree that it is possible to use RCA to manufacture HMA. However, HMA made with RCA displays increased optimum bitumen content than mixtures made with only with natural aggregates [7,[9][10][11][12][13][14][15]. The high porosity of the attached mortar [7,15] appears as mainly responsible for this increased bitumen consumption.…”

Evaluation of Marshall Compactor Effect on the Degradation of Recycled Concrete Aggregate

“…As a result, the asphalt content of the mixture is optimised [10]. The optimal asphalt content is contingent upon RCA particle size [11], as smaller particles have a larger surface area-to-volume ratio [12].…”