On a busy stretch of the Chennai-Tirupathi National Highway, engineers are quietly conducting a trial that could reshape how India builds its roads. Using reclaimed asphalt from the old roadway, mixed with a special rejuvenating additive, they've laid down a new 1-kilometer test section that contains 60% recycled material—double what current standards allow.

Key facts

  • 1 km test section on Chennai-Tirupathi National Highway
  • Uses 60% reclaimed asphalt (double the current 30% limit)
  • Technology developed by CSIR-Central Road Research Institute
  • Commercial production by Ooms Polymer Modified Bitumen Pvt Ltd.
  • Road widening by Oriental Structural Engineers Private Limited

The Science Behind the Savings

Over time, the top layer of bituminous roads loses its elasticity, becoming brittle and less effective. Rather than sending this material to landfills, scientists at CSIR-CRRI developed a rejuvenating additive that can be mixed with cold-milled reclaimed material to restore its strength. "CSIR-CRRI has developed a rejuvenating additive that can be added to cold-milled material to strengthen it for reuse in road laying," explained Chalumuri Ravi Sekhar, Director of CSIR-CRRI.

From Laboratory to Highway

Though the technology was developed two years ago, this marks its first significant field demonstration. The research institute has transferred the technology to Ooms Polymer Modified Bitumen Pvt Ltd. for commercial production, while Oriental Structural Engineers Private Limited handles the actual road widening work. National Highways Authority of India (NHAI) is overseeing the trial, which represents a collaboration between research, industry, and government.

"The Indian Roads Congress Code permits the re-use of 30% bitumen for road re-laying. Now this advancement will allow the use of 60% of the reclaimed material, which is usually sent to the dump yard."
— Ravi Shankar, CSIR-CRRI senior scientist

Broader Implications

If successful, this approach could significantly reduce India's road construction costs and environmental impact. Ravi Shankar notes that "in the long run, recycling bitumen will help reduce dependency on foreign exchange" since India imports much of its bitumen. The team will submit their results to the Indian Roads Congress, which may incorporate the higher recycling rate into national building codes. Highways Research Station Director Venkatachalam acknowledged the potential: "The 60% utilisation seems to bring up interesting possibilities. We will wait for the IRC Code to put it to use."