Evaluation of volumetric performance of asphalt mixtures containing recycled construction aggregate (RCA)

High rate of construction and demolition waste materials results in a large amount of stockpiled waste materials. Pavement industry is now considering a sustainable approach for asphalt mixture design incorporating certain waste materials. This research investigates the feasibility of substitution of virgin aggregates in asphalt mixes with recycled construction aggregates (RCA) obtained from the construction and demolition sector. A preliminary experimental study including determination of flakiness index, particle shape, wet/dry strength variation, water absorption rate, particle density, crushing value, deleterious material and weak particles was conducted on blends of RCA and virgin aggregates to evaluate the engineering properties of aggregate blends. Different asphalt mixes incorporating RCA at different rates were prepared and evaluated using a gyratory compaction. The results of the regression analysis showed that the asphalt mixtures containing 20% to 22% RCA provide comparable volumetric properties as the control sample, while mixes with higher RCA substitutions achieved higher air voids, and lower voids in the mineral aggregate (VMA), voids filled with asphalt (VFA) and binder film index (BFI). The results of this study suggested a feasible use of RCA for partial aggregate replacement in hot mix asphalt (HMA).

Automated summary

The high rate of construction and demolition waste materials leads to an increase in stockpiled waste materials. This study investigates the feasibility of using recycled construction aggregates (RCA) obtained from the construction and demolition sector as a substitute for virgin aggregates in asphalt mixes. The results show that asphalt mixtures containing 20% to 22% RCA provide comparable volumetric properties to the control samples, indicating that the use of RCA for partial aggregate replacement in hot mix asphalt (HMA) is feasible.