Are recycled and low temperature asphalt mixture more sustainable

Innovations are necessary to achieve reduction of both CO2 emissions and use of fossil materi-als during construction and maintenance of roads. To enable selection of promising innovations and to facili-tate material selection in green procurement, quantitative tools to assess both life cycle costs and environmen-tal impacts are used. In this research, environmental product indicators of asphalt innovations were used to investigate the environmental consequences of the strategic decision of the Dutch national road administration Rijkswaterstaat to use “green” porous asphalt (PA) top layers. Sustainable asphalt mixtures that were pro-duced at low temperatures and/or with different degrees of reclaimed asphalt were compared to a reference hot mix PA. Asphalt with recycled content turned out to have 4%-5% lower life cycle costs than the reference mixture and caused 12%-17% less CO2 emissions. Low temperature mixes were estimated to cause 5%-10% less environmental impacts than the reference, but the costs increased with a few percent due to the addition of rejuvenators. Life time expectancy is relevant for the outcomes of the comparison: if the sustainable asphalt mixtures would have a two year shorter life timer, the environmental and cost impacts would overshoot the reference impacts. Suggestions for further research are 1) to monitor lifetime of sustainable pavements and 2) to decrease uncertainty in the environmental results by updating this study when more information on the as-phalt environmental profiles is available and 3) to investigate in cost and environmental assessment of other solutions for more sustainable asphalt, such as self-healing, rejuvenating, and reduced resistance and fuel con-sumption.