Research Projects

Bituminous mixes are primarily composed of asphalt (i.e. bitumen) binder (4-8% by mix weight) and mineral aggregates. Despite bitumen lower percentage it makes up approximately 40-50% cost of materials and plays critical role in durability (i.e., resistance to rutting, cracking and moisture damage) of bituminous mix in-service. The bitumen is produced via refining crude oil and considered as non-renewable in nature. Notably, the emerging sensitivity on environmental concerns and scarcity of natural resources, presently the bitumen industry is looking to develop a sustainable (i.e. renewable and environment friendly) alternative of bitumen. The need is more critical for countries like India where not only the demand of bitumen for road construction is increasing but also supply heavily reliant on import of crude oil and bitumen. In FY24, the sales of bitumen for road construction in India rose by 10% to 8.8 million tonnes and more than 40% of total bitumen is imported. In view of above needs, presently the concept of biomaterials incorporation in bitumen to replace conventional Petroleum-Based bitumen is gaining momentum. Lignin is one such biomaterials, which partial replacement in bitumen offers attractive and environment conscious solution. Lignin is the second most abundant (available in large volume) and widespread biopolymer on earth after cellulose. Primarily, it is coproduct of pulp paper industry and 2nd generation ethanol biorefineries. The total amount of bitumen used worldwide is estimated as 70 million ton annually, whereas the current amount lignin produced via pulp paper industry is possibly 50 million ton and will increase. Like, bitumen the lignin has natural binding characteristics. Moreover, from chemical point of view it is known that the lignin three-dimensional cross-linked macromolecule and bitumen have certain chemical similarity like both has polar and nonpolar compounds, availability of hydrocarbons with hydrogen, carbon and oxygen. Also, the lignin structure resembles with resin and asphaltene fraction of bitumen. The addition of lignin has shown positive impact on rheology of bitumen. It not only improved the aging resistance of bitumen but also enhances the physical behaviour by improving high temperature performance (increase in complex modulus and decrease in phase angle). Whereas no univocal effects on intermediate and low temperature performance have been observed. The limited recent studies on lignin modified bituminous mixes showed increased stiffening, improved rutting and moisture resistance. The proposed approach has significant environmental benefits and value addition for co-product of pulp paper and biorefinery industries. As the institute located in agriculture rich landscape with availability of around nine pulp paper units and couple of bio-refineries in region, the required lignin will be obtained. Moreover, one of bioenergy-based industry also agreed to supply lignin. After successful completion of the project a small field road section will be planned in our campus or nearby region.