The road construction sector is one of the largest consumers of bitumen. The fast depletion of limited bitumen resources has compelled researchers to adopt alternate binders to construct asphalt pavements. Biomass sources have gained attention as a means of modifying the conventional asphalt binder to meet all of the performance parameter requirements of different climatic conditions. This paper reviews the properties and application of biomass-derived sustainable products. It discusses two widely used primary thermochemical conversion processes: pyrolysis and hydrothermal liquefaction. The effect of the chemical compositions of the bio-oils extracted from different biomass sources is reviewed. After comprehending the properties of bio-oils and the blending of bio-binders, the standard, chemical, and rheological properties of bio-oil-modified binders are reviewed in detail. The performance parameters of bio-oil-modified bituminous mixtures are also reviewed to check the adaptability of bio-oil to and its compatibility with the bituminous mixture. The review reveals that the properties of bio-oil vary drastically with the biomass resource. There are numerous aspects that need to be considered in relation to the oxidative aging of the bio-oil-modified binder and mixtures, which affects the performance at low- and intermediate-temperature conditions. It is observed that the addition of most biomass-derived bio-oils, which are fluid in nature at ambient temperature, leads to better performance at low and intermediate temperatures but undesirable performance at high-temperature conditions because of significant changes in the stiffness of the material. It is found from the review that treating a copolymer with or adding it to bio-oil can enhance the material's properties, resulting in better performance in severe field conditions and, at the same time, making it an environmentally friendly material.
Read full abstract