Road Construction with Reduced Environmental Impacts: Performances and Innovative Evaluation Method

As a substantial source of greenhouse gas (GHG) emissions and energy consumption, the road construction domain has to bring a contribution to the reduction of the environmental impacts. Indeed, an important part of the energy consumption and consequently environmental emissions can be attributed to the construction phase of the roads. During the production and compaction phases, a low viscosity of the bituminous mixture is required and this generally necessitates a temperature above 150 °C (hot mix asphalt - HMA). In order to reduce the environmental impacts, various types of warm mix asphalt (WMA) have been developed during the last fifteen years. The uses of these mixtures is however still limited in Europe, in particular because of the lack of knowledge concerning the performances, and the difficulty of choice between numerous products. The presentation will firstly describe the major technologies and performances that can be expected. A model for the choice of the most adapted technology will then be introduced. Indeed, the choice of the most favorable mixture for a given project is not necessarily straightforward and few of the GHG calculators currently available are able to perform a comparison at the asphalt mixture scale – despite the clearly important effects of the asphalt mixture type. The developed multi-criteria methodology takes into account various aspects such as mechanical performance and other qualitative criteria. The proposed model finally helps the road owner in his decision making process and optimizes the environmental impacts reduction.