Performance of bio-asphalts: state of the art review.

The global population spike, rise in industrialization, and highway infrastructure development induce focus on sustainable development. The ever-increasing consumption of non-renewable crude oil and asphalt levies a heavy toll on economic welfare of future generations. This enormous demand of asphalt is due to its wide applicability in flexible pavements. Therefore, the construction industry is exploring the partial substitution of renewable materials in asphalt with a focus on economical, social, and environmental benefits. The current decade has seen a rampant rise of bio-asphalt as an alternative to asphalt. Hence, it is imperative to explore the performance of bio-asphalt for its sustainable applicability. This review comprehensively summarizes the performance of bio-asphalt obtained from various biomass sources. It deals with elemental composition of bio-oil, preparation procedure, rheological performance, mixture performance, and aging mechanism of bio-asphalt along with modification required to improve the performance. The environmental impacts and field application of the bio-asphalts are also discussed.