Bitumen, a black, viscous material derived from crude oil, is commonly used as a binder in road construction. Lignin, on the other hand, is a natural polymer found in plant cell walls and is abundant in agricultural waste.
Processing lignin into bio-bitumen offers an environmentally friendly solution with up to a 70% reduction in greenhouse gas emissions compared to conventional bitumen.
Along with bio-bitumen, it also has 10% rubber powder, further cutting the proportion of petroleum bitumen.
India imports 50% of its bitumen requirements, costing ₹25,000–30,000 crore annually. For this project alone, which features up to 15% bio-bitumen blending, savings of ₹4,000–4,500 crore in foreign exchange have been estimated. To meet a 15% blending target, around 15 lakh tonnes of bio-bitumen would be needed.
The viability of lignin-based bio-bitumen was first tested on a service road in Halol, Gujarat. After two and a half years and three monsoon seasons, the CSIR-CRRI confirmed its durability with no signs of distress. The Nagpur-Mansar highway could also be a demonstration of how scalable this technology is for larger projects.
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The success of this project will be determined over the next two years as the CRRI evaluates the road’s performance under heavy traffic and varying weather conditions. According to a CRRI scientist, the bio-bitumen will pass the endurance test if the road’s deflection remains within 0.4mm during this period.
CRRI will submit a detailed report on the results based on blending performance, said Union Minister Nitin Gadkari. Once the report is finalised, bitumen manufacturers will be directed to develop a policy for sourcing lignin for blending purposes. Currently, 40-grade bio-bitumen, known to be stronger than its conventional counterpart, has been developed.
Gadkari also noted that this marks an initial step toward sourcing raw materials for bitumen from farmers, aligning with the broader goal of fostering sustainable infrastructure.
Union Minister Nitin Gadkari, while inaugurating the project, highlighted the dual economic and environmental benefits. He stated, “The bio-bitumen used in this project reduces dependency on imports and transforms agricultural waste into a valuable resource. Farmers will evolve as not just food producers but also energy providers.”
India’s bitumen consumption is expected to grow from 88 lakh tonnes in FY24 to 100 lakh tonnes in FY25. This innovation aligns with the Aatmanirbhar Bharat mission by reducing import dependency and boosting domestic production, the company said.
At around 1.30 pm, shares of Praj Industries were trading at ₹820.40, up 1.8%, on the BSE. The stock touched an intraday high of ₹839, gaining over 4.5% during early trade.
