Mohammad Hanief
India’s road construction sector is poised for a significant transformation with the successful transfer of an indigenous bio-bitumen technology that converts agricultural residue into a sustainable alternative to conventional petroleum-based road binders. Developed jointly by the CSIR-Central Road Research Institute (CRRI), New Delhi, and the CSIR-Indian Institute of Petroleum (IIP), Dehradun, the innovation signals a decisive move towards cleaner, greener, and more self-reliant highway infrastructure.
Bio-bitumen is produced through the pyrolysis of post-harvest biomass such as rice straw, a process that enables farm residue to be repurposed as a high-value industrial input. The technology directly addresses two of India’s pressing challenges: the environmental impact of fossil fuel dependence in infrastructure and the large-scale burning of crop residue after harvest. By linking agricultural waste management with road construction, the innovation establishes a circular economy model with nationwide relevance.
India’s expanding highway network currently relies heavily on petroleum-derived bitumen, nearly half of which is imported. This dependence exposes the sector to volatile global prices and results in a substantial foreign exchange burden. The introduction of bio-bitumen offers a domestic alternative that can partially substitute conventional bitumen while maintaining performance standards required for high-traffic roads. Laboratory studies have shown that blending bio-bitumen at levels of 20 to 30 per cent does not compromise structural integrity or durability, making it a viable option for mainstream adoption.
The production process begins with the systematic collection of post-harvest crop residue, which is pelletised to ensure uniform feedstock quality. The pellets are then subjected to pyrolysis, a controlled thermal process conducted in the absence of oxygen. This treatment produces bio-oil, which is subsequently refined and blended with conventional bitumen to create a road binder suitable for paving applications. The process has been designed to be energy-efficient and emission-free, enhancing its environmental credentials.
Extensive validation of the bio-bitumen blend has been carried out to ensure compliance with national and international road construction standards. Researchers evaluated the material through a wide range of physical, rheological, chemical, and mechanical tests. Performance assessments included resistance to rutting under high temperatures, cracking behaviour under stress, susceptibility to moisture damage, and resilient modulus measurements. The results demonstrated parity with conventional bitumen, reinforcing confidence in the material’s suitability for long-term infrastructure use.
Field-level feasibility has already been established through a pilot project on the Jorabat-Shillong Expressway in Meghalaya, where a 100-metre stretch of road was laid using the bio-bitumen blend. The trial confirmed the material’s workability during construction as well as its performance under real traffic and climatic conditions. The success of this demonstration has strengthened the case for scaling up the technology across national and state highway projects.
Beyond its application in road construction, the bio-bitumen production process yields several valuable co-products that enhance its economic viability. Pyrolysis generates energy-rich gases that can be used as fuel within the system, reducing external energy requirements. It also produces bio-pesticide fractions and high-grade carbon materials with applications in batteries, water purification, and advanced manufacturing. These multiple value streams contribute to the overall sustainability and cost-effectiveness of the technology.
The development is particularly significant in the context of India’s efforts to reduce import dependence. With annual bitumen imports valued at an estimated ?25,000-30,000 crore, even partial substitution through bio-bitumen could result in substantial savings. At the same time, the technology creates new economic opportunities in rural areas by generating demand for agricultural residue that was previously treated as waste. Farmers stand to benefit from additional income streams, while local processing units can stimulate employment and regional development.
The rapid progression of bio-bitumen from laboratory research to industrial-scale technology transfer highlights the growing maturity of India’s applied research ecosystem. A patent has been filed for the process, and multiple industrial partners have been engaged to facilitate commercial production and deployment. India has emerged as the first country to move bio-bitumen technology to industrial and commercial readiness within the same year, positioning itself as a potential global leader in sustainable road materials.
The successful integration of alternative materials into infrastructure projects is not without precedent in India. Previous initiatives involving waste plastic, steel slag, and bio-fuels have demonstrated that non-conventional inputs can meet performance benchmarks while delivering environmental benefits. Bio-bitumen builds on these experiences, offering a scalable and scientifically validated solution that aligns with climate commitments and development priorities.
Policy-level integration is expected to play a crucial role in the widespread adoption of bio-bitumen. The inclusion of blended bio-bitumen in national highway specifications would provide regulatory clarity and market confidence, encouraging contractors and state agencies to adopt the material. Region-specific implementation strategies, based on the availability of agricultural residue, could further optimise deployment and maximise impact.
As India continues to expand its road network to support economic growth and connectivity, the choice of construction materials will increasingly influence environmental outcomes. Bio-bitumen represents a shift in thinking, where infrastructure development is no longer viewed in isolation from sustainability goals. By transforming farm residue into durable highways, the technology demonstrates how indigenous innovation can simultaneously address pollution, resource efficiency, and self-reliance.
The successful transfer of bio-bitumen technology marks a critical step towards redefining how India builds its roads. It underscores the potential of science-driven solutions to reshape traditional sectors and positions the country on a path towards cleaner, greener, and more resilient infrastructure for the future.
(The author is a senior analyst)
