Assessing the Mechanical Performance of Asphalt Mixes with Alternative Binders Containing Biomaterials

As the climate crisis continues to grow and the crude oil stock continues to dwindle, alternatives to conventional asphalt binders are being investigated. These alternatives typically consist of biomass and/or waste materials. While their use may reduce the environmental impact of asphalt pavements, their effect on the mechanical performance of asphalt mixtures remains largely unknown. The objective of this study was to assess the mechanical performance of three asphalt mixtures with alternative binders containing bio-based sources. In two cases, the conventional binder was partially replaced with raw biomaterial (15% binder replacement), namely microalgae and poplar sawdust. In the third mix, the conventional binder was completely replaced by a commercially available bio-extended polymer-modified bitumen (PMB). To evaluate the mechanical performance of the mixes, their water susceptibility and cracking performance were tested, besides the necessary volumetric properties. This study found that cracking performance did not deteriorate by the partial replacement of the binder with a biomaterial. However, moisture resistance declined drastically when adding sawdust or algae. Based on the results, a full replacement of the conventional asphalt binder with the commercial bio-extended PMB used in this study is feasible.