India’s road infrastructure plays a crucial role in economic development, but it also poses significant environmental challenges. With the rapid expansion of highways and expressways, the construction and maintenance of roads consume large amounts of natural resources and contribute significantly to carbon emissions. However, leading experts in the industry are pioneering sustainable practices to mitigate environmental impact and improve efficiency. At a webinar titled, “Paving the Future: Making India’s Roads More Sustainable”, held on March 5, 2025, industry stalwarts gathered to discuss India’s road infrastructure, exploring innovative solutions to address the environmental challenges posed by rapid expansion, and the adoption of sustainable practices for long-term economic and ecological benefits.Transforming road asset managementDr Zafar Khan, Joint CEO, Highway Concessions One, highlighted that roads rank among the least sustainable infrastructure components owing to high emissions from construction and maintenance. “From an asset management perspective, we have already taken key steps such as switching to LED lighting and integrating solar power wherever net metering is allowed by the Government,” he said.Despite these efforts, a major challenge remains fuel consumption in maintenance activities, particularly in heating materials for road repairs. In response, Highway Concessions One has initiated a large-scale mangrove plantation project along India’s coastal belt. “Mangroves have the highest carbon sequestration capacity and we are planting 50 lakh mangroves over a three-year period to neutralise our carbon footprint,” shared Dr Khan.Another promising development has been the use of plastic waste in road construction. “After six years of study, we have successfully used 500 tonne of plastic waste in constructing a 72-km National Highway stretch,” he added. “While authorities remain cautious about widespread adoption, this initiative has demonstrated durability and environmental benefits.” Innovations like video surveillance-based lighting, which reduces energy usage by optimising illumination based on traffic density, are also being explored.Role of material innovationDecarbonising road construction materials is a key area of research. Satish Pandey, Senior Principal Scientist and Head - Flexible Pavement Division, CSIR – Central Road Research Institute (CRRI), emphasised the potential of alternative materials. “Road construction heavily relies on natural aggregates but we need to look at industrial waste alternatives like processed steel slag,” he said.One of the most promising advancements in this area is the adoption of steel slag roads, where natural aggregates are entirely replaced with steel industry byproducts. “CRRI has been working with industries to integrate steel slag into road layers,” he added. “This approach not only reduces carbon emissions but minimises the depletion of natural resources.” Recycling also plays a crucial role in sustainable road construction. “If we maximise the reuse of reclaimed asphalt pavement (RAP) up to 70 per cent, we can significantly cut down on the need for virgin bitumen and natural aggregates,” Pandey pointed out. The use of blended cement, such as Portland slag cement, is another effective method to lower emissions. “By incorporating ground granulated blast furnace slag (GGBFS), cement consumption can be reduced by 40 to 50 per cent, cutting down carbon emissions from cement production,” he added.Addressing pavement durability Dr Yonghong Ruan, Asphalt Technology Manager, Honeywell, emphasised the need for materials that can enhance the performance of asphalt, saying, “Pavement durability is an ongoing challenge and we know that roads around the world are subject to thermal cracking, fatigue cracking and permanent deformation. These are all signs that the road needs better performance.” To address these issues, Honeywell introduced Titan®, a polymer designed to modify bitumen to produce polymer-modified bitumen (PMB), significantly improving the overall performance of the pavement. Honeywell Titan® enhances the stiffness of the binder at high temperatures while improving its lubricity, making compaction easier and increasing pavement density. This results in smoother and more durable surfaces.Adding to this, Swapnil Kanaujia, R&D Engineer, Honeywell, shared how Titan® has proven effective in India’s most extreme climates — from the icy terrain of Ladakh to the rain-heavy Northeast and the scorching heat of Rajasthan. “India’s geographical diversity requires tailored solutions,” he stated. “We understood that until we hit the ground, we wouldn’t fully grasp the exact problems we were solving.” Kanaujia explained that Honeywell’s hands-on approach led to projects where roads remained intact even after enduring -35°C in Ladakh or 50°C in Rajasthan, demonstrating the resilience and sustainability of their technology. “Honeywell Titan® helps reduce maintenance cycles, potentially cutting down one maintenance cycle within a decade,” he concluded.Overcoming challenges Despite technological advancements, regulatory and financial hurdles hinder widespread adoption. Dr Khan noted that economic considerations often dictate decision-making in infrastructure projects. “There is no lack of research or documentation – it’s about economic viability,” he asserted. “If a technology proves cost-effective, it will find its way into mainstream use.” Trust between authorities and concessionaires remains a challenge. Dr Khan highlighted that earlier contracts allowed for performance-based maintenance but recent shifts have reverted to fixed maintenance cycles. “Even if we propose innovative materials like RAP, authorities hesitate due to concerns over commercial benefits,” he pointed out. “If I take the risk, I should be able to reap the rewards.”Pandey agreed that regulatory reluctance slows innovation. “If new materials and technologies are already included in the Indian Roads Congress (IRC) guidelines, why should authorities resist their adoption?” He suggested that a comprehensive document consolidating all alternative approaches should be created to improve awareness and facilitate smoother implementation.Incentivising sustainable practicesFor sustainable road construction to become mainstream, policymakers need to implement incentive mechanisms. Dr Khan proposed that making alternative materials mandatory within a certain radius of production facilities could enhance their adoption. “When fly ash was mandated within 200 km of power plants, it became widely used. The same approach should be applied to steel slag and plastic roads.”Pandey emphasised the need for performance-based contracts instead of rigid specifications. “Globally, road quality is monitored based on performance metrics such as roughness and structural deflection. If contractors are required to maintain roads to a specific standard over five years, they will naturally adopt cost-effective and sustainable materials,” he reasoned.Another potential approach is linking infrastructure financing to environmental criteria. “If 20-30 per cent of road project lending is tied to sustainability-linked bonds or green finance, concessionaires will be incentivised to integrate ESG (Environmental, Social, and Governance) principles into their projects,” Dr Khan noted.Exploring the potential of bio-bitumenDr Gurunath Guduru, Manager - Pavement & Quality Assurance, Sekura India Management, shed light on the potential of bio-bitumen as a sustainable alternative to petroleum-based bitumen. “India is actively researching bio-bitumen applications and we have conducted test sections in collaboration with CRRI. While the material is still in its early stages, initial results are promising,” he shared.He also highlighted that hot and cold recycling technologies significantly reduce lifecycle costs. “By using additives tailored to project needs, we can extend pavement life and minimise maintenance. For instance, in the Northeast, we applied Honeywell Titan to combat rutting and moisture damage and the road remains in excellent condition a year later,” he said.The way forwardFor sustainable roads to become a reality, collaboration between additive manufacturers, researchers, and construction firms is essential. Himanshu Pathak, Product Manager, Honeywell, stressed the importance of data-driven decision-making. “Claims about sustainability need to be backed by rigorous testing and real-world trials,” he stated. “If an additive can reduce processing time from 15 hours to five hours, we need verifiable data to substantiate these benefits.”Ultimately, the goal is to build long-lasting, environment-friendly roads without compromising on quality. “Sustainable road construction is not just about reducing emissions; it’s about optimising resources, improving durability, and making economic sense,” Dr Khan concluded.India stands at a crossroads in infrastructure development. By integrating innovative materials, leveraging recycling technologies and creating policies that reward sustainability, the country can pave the way for a greener, more resilient road network. The momentum is there – now is the time to drive change.