A 1 km-long stretch of the access-controlled Chennai-Tirupathi National Highway that is currently being widened has been laid by utilising 60% of the asphalt pavement that had been reclaimed from the old road and rejuvenated. This successful field demonstration for bitumen was possible thanks to technology developed by CSIR-Central Road Research Institute (CSIR-CRRI).  

The top bituminous layer of the road, which has been in use for several years, loses its elasticity. 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, CSIR – CRRI.  

Though the technology was developed two years ago, it has been tried out in small sections so far. Since CSIR-CRRI has transferred the technology to Ooms Polymer Modified Bitumen Pvt Ltd. (Ooms India) for commercial production, that company and Oriental Structural Engineers Private Limited (OSEPL), which is widening the road, have joined hands with the National Highways Authority of India (NHAI) to conduct the trial.  

“The Indian Roads Congress (IRC) 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. In the long run, recycling bitumen will help reduce dependency on foreign exchange. We will also submit the results to the IRC, which may incorporate it into the code,” explained Ravi Shankar, CSIR- CRRI, senior scientist. The team that developed this additive and the technology includes Ambika Behl, senior principal scientist, Rajiv Kumar, Senior scientist and Siksha Swaroopa Kar, senior principal scientist.   

Recently, scientists from the Institute visited the site at Tiruvallur and ensured the methodology and procedure were used correctly. Highways Research Station Director Venkatachalam said Tamil Nadu had been reusing 30% bitumen wherever possible. “The 60% utilisation seems to bring up interesting possibilities. We will wait for the IRC Code to put it to use,” he added.