NH-716 Trial Showcases 60% Recycled Pavement Technology in Highway Construction
A field trial on NH-716 successfully used 60% reclaimed asphalt pavement in a new road layer, highlighting indigenous rejuvenation technology.
A significant field-scale demonstration on National Highway-716 (Chennai–Tirupati Package-I) has showcased the use of 60% Reclaimed Asphalt Pavement (RAP) in the Dense Bituminous Macadam layer. The trial was a collaborative effort involving CSIR-Central Road Research Institute (CSIR-CRRI), Oriental Structural Engineers Private Limited (OSEPL), and Ooms Polymer Modified Bitumen Pvt. Ltd. (Ooms India).
The demonstration was attended by senior officials from the National Highways Authority of India (NHAI) and the Government of Tamil Nadu, along with industry stakeholders. It showcased the complete high-RAP recycling process, from material recovery and characterisation to rejuvenation, mix design, plant production, and field compaction. Visitors also toured the hot mix plant and an Experience Centre that illustrated the journey of reclaimed asphalt.
RAP as a Resource
Reclaimed Asphalt Pavement contains valuable aggregates and aged bitumen that can be scientifically recovered and reused. At a 60% utilisation rate, a substantial portion of the new asphalt mix is derived from existing pavement. This approach conserves natural resources, reduces dependence on virgin materials, and lowers the environmental footprint of highway construction, treating existing roads as a "resource bank."
Indigenous Rejuvenation Technology
A key element of the trial was the use of REJUBIT, an indigenous RAP rejuvenator jointly developed by CSIR-CRRI and Ooms India. The technology is designed to restore the properties of aged bitumen, enabling a higher proportion of reclaimed material to be incorporated into new mixes. Its successful application marks the progression of this research-led technology from the laboratory to field-scale implementation.
Expert Perspectives
Dr. Chalumuri Ravi Sekhar, Director of CSIR-CRRI, stated that RAP should be viewed as an engineering resource, not waste. He noted that the demonstration brings together the complete recycling chain under actual field conditions, which is crucial for building confidence and establishing a scientific pathway for greater material reuse.
Dr. Ambika Behl, Senior Principal Scientist at CSIR-CRRI and Project Leader, described RAP as "black gold for the road sector," containing non-renewable aggregates and bitumen. She emphasised that the trial shows how higher recycling levels can be achieved through rigorous characterisation and scientific mix design.
Representatives from OSEPL and Ooms India highlighted the significance of moving from laboratory design to live highway laying while maintaining quality control. The Chief Guest, Sh. Er. A. Venkatachalam, Director of the Highway Research Station in Chennai, called the demonstration a milestone for Tamil Nadu, noting the state's road network offers significant potential for recycling.
The trial section was executed under the technical guidance of CSIR-CRRI, with Dr. Ambika Behl leading the project and Dr. Rajiv Kumar involved in design and construction. The initiative aims to generate field experience and contribute to the evidence base for the wider adoption of high-RAP recycling in Indian highway projects.