Performance of asphalt mixtures with partial replacement of fossil binders by bio-based binders

The interest in using bio materials in asphalt pavements gas grown considerably in the last decade due to their potential economic and environmental benefits. In fact, their use can help in diminishing the consumption of traditional fossil based binder and absorbs a substantial amount of biomass, allowing the decarbonization process of the road construction sector. In literature, different bio materials coming from different sources (forestry and agriculture crops and residues, industrial residues, sewage, municipal solid waste, animal residue) and obtained with different processes (bio refinery, precipitation and separation processes, enzymatic hydrolysis, etc.) can be found and they can be served as additive, modifier or partial/total substitute of the fossil based binder. In the last decade, researchers have developed bio based binders to substitute partially (bio extender) or completely (bio binder) the fossil-based one, but most of these products are derived from complex and expensive processes and they may have a negative impact on land use, moreover they are using expensive resins and synthetic polymers to improve the overall performances. Therefore, in future research efforts, it would be vital to find biomasses from waste feedstock available locally in large quantities, which can be more attractive on the economic and environmental point of view. In addition, the use of wastes polymers in combination with bio materials could be the key for replacing large quantities of fossil based binder without compromising the performances of the mixture and of the pavement and could be the best environmental, economics and sustainable solution compared to the fossil based asphalt mixtures. In the present chapter, the performance properties of asphalt mixtures composed with bio materials used as bio extenders, considering a percentage of fossil binder replacement greater than 20% will be presented.