Asphalt mixtures with construction and demolition debris

This paper reports on research into the technical viability of the use of construction and demolition debris in hot-mix asphalt. A semi-dense and a coarse asphalt mixture were studied, both containing 50% recycled aggregate from construction and demolition debris. Two control mixtures were also studied, similar in grading but not containing recycled aggregates. It was shown that the mixtures containing recycled aggregates were more open graded and had considerable potential for stripping, a characteristic that can be related to the high water absorption level of the mortar adhered to the recycled aggregates. It was also shown that the dynamic modulus was higher in the mixtures made with recycled aggregates, particularly in the semi-dense asphalts. Whereas a deterioration of the fatigue law was observed in the semi-dense mixtures, this property did not appear to worsen in the coarse mixtures. This meant it was possible to design structural sections for flexible pavements bearing medium or low volumes of traffic with a service life comparable with that of conventional materials. Nevertheless, further research is required as, for the time being, the lack of resistance to water action casts doubt on the use of asphalt mixtures incorporating these types of recycled aggregate.