Sustainable paving alternative for low-volume roads using cold recycled asphalt

Abstract

Reclaimed asphalt pavement (RAP) is a waste generated by removing asphalt material from a pavement. If RAP is not recycled, the pavement will require new asphalt layers, typically formed by virgin materials (bitumen and aggregates). One way to recycle RAP is by applying the cold-asphalt technique with bitumen emulsion as an additive, which potentially has environmental benefits. This technique can be a cost-effective alternative for low-volume road (LVR) networks that connect to main asphalt-paved roads. The objective of this research is to analyse the alternative of paving with RAP using cold bitumen emulsion as a binder. This pavement structure was compared with a traditional hot-mix asphalt pavement as an alternative for LVRs. The environmental impact analysis, through a streamlined life-cycle analysis, showed that the cold recycled alternative typically generates 50% less impact than a traditional pavement. In terms of global warming, the hot-mix asphalt pavement generates three times more emissions than the cold recycled alternative. The most important factors in these differences are the in situ construction technique of the RAP alternative and, as is the case in Chile, the long distances to a hot-mix asphalt plant.