Mechanical properties of hot-mix asphalt made with recycled concrete aggregates coated with bitumen emulsion

The incorporation of recycled concrete aggregates (RCA) in hot-mix asphalt (HMA) could be a way to promote sustainable construction. To date, several investigations have examined the use of this type of waste material in HMA. Several researchers have observed that due to the action of water, the use of this material proved to have insufficient durability. In this investigation, a laboratory characterisation of HMA made with RCA from construction and demolition waste (CDW) for base layers in road pavements was conducted. Percentages of 5%, 10%, 20% and 30% of RCA in place of natural aggregates were analysed. To improve the water resistance of the mixes, the RCA were coated with 5% of bitumen emulsion prior to the mixing process. The results indicated that the mixes comply with the Spanish water resistance specifications required for base layers. The stiffness, permanent deformation and fatigue of the mixtures were also studied. The results indicated that HMA made with RCA coated with bitumen emulsion exhibited mechanical properties similar to those obtained for conventional mixtures.