Very high recycling rate (>50%) in hot mix and warm mix asphalts for sustainable road construction

Abstract

Nowadays, the criterion of materials -and cost- savings without sacrificing performance is systematically taken into account by building owners, prime contractors, asphalt producers and road contractors. In-plant reclaiming of asphalt pavement (RAP) at high rate is more and more often used within the framework of rehabilitation or maintenance roadworks. The maximum value of RAP content is generally between 20% and 50% according to the considered asphalt plant equipment limitations. This paper focuses mainly on the analysis of the effect of the RAP content along with the mix productiontemperature on the mix performances. Some mixtures were studied both in laboratory and on the field with RAP content ranging from 10 to 90%, along with two different production temperatures: 160degreesC (conventional temperature of the hot mix asphalt) and 95degrees (proprietary low energy asphalt technique labelled LEA). Such very high RAP contents (>50%) could be used thanks to a very innovative asphalt plant allowing both hot and warm recycling. Characterisation of the studied asphalts produced in laboratory or in plant shows that very high recycling rates in hot mix or warm mix asphalts can be used as a cheap and efficient way to minimize environmental impacts. For the covering abstract see ITRD E157233