NANO TECHNOLOGY FOR SELF-REPAIRING ROADS
By TA News Bureau:
Fibres from end-of-life tyres have found a new application with the invention of futuristic self-repairing of roads by Dr Nemkumar Banthia, Professor of Civil Engineering at the University of British Columbia. He is also CEO of India-Canada Centre for Innovative Multidisciplinary Partnerships to Accelerate Community Transformation and Sustainability (IC-IMPACTS). The roads built using this technology are found to last longer and cheaper to build and maintain. They are more sustainable from an environmental perspective too. He has built a demonstration project to test this technology in Thondebavi village, 90 km from Bengaluru (India). The India-born Canadian researcher has developed the road construction material in such a way that adding scrap tyre fibres to the concrete has shown to improve its resilience and extend the road’s lifespan. In this interview he explains to Tyre Asia the benefits of the technology that he has developed which is environmentally sustainable
Can you explain your research on the technology that can be used to make self-repairing roads?
There are three billion tyres produced each year around the world. When recycled, these tyres generate about three billion kilograms of fibre. We are transferring the by-product of one industry, which would otherwise be disposed of, to another industry as a recycled material. In doing so, we are not only fixing the problem of tyre disposal, but also reducing the carbon footprint of the concrete industry.
In some other fibre types and concrete formulations (excluding tyre fibre), research at our SIERA (Sustainable InfrastructurE ReseArch) facility at the University of British Columbia has shown that cracks can also heal themselves. As cracks form in the concrete, nano-coated fibres prevent them from widening, and produce additional materials in a high humidity environment that allow the cracks to heal. This was the technology used in the road built in Tondebhavi near Bengaluru.
It is said that roads built using this technology last longer and are cheaper to build. Can you throw some light on your observation?
Because of this self-healing mechanism (described above), the concrete developed requires much less maintenance than the typical material used to pave roads.
We have developed a concrete mix that reduces the required cement component by 60 per cent, replacing it with locally sourced flyash. Reducing the amount of cement significantly increases the developed material’s sustainability, as the cement industry currently contributes around five to seven per cent of global emissions.
What has been the outcome of your road project in Thondebavi village?
The material was used for the construction of a road in the village of Thondebavi. The India-Canada Centre for Innovative Multidisciplinary Partnerships to Accelerate Community Transformation and Sustainability (IC-IMPACTS) funded the project. The project demonstrated that this technology could be implemented in many rural and remote locations around the world. It is a low-cost material requiring minimum maintenance and we anticipate the road in Thondebhavi will last as long as 15 years before needing maintenance.
The road has been monitored now for over a year and the results are good as expected. A condition assessment of the pavement indicates that the material is performing well under heavy rains and extreme heat. Other tests performed by the SIERA group predict it should also perform well in extreme cold conditions.
While use of recycled tyre crumbs in pavement application is fairly accepted universally, the use of polymer fibres for tyres is unique as it improves resilience of concrete while extending its life-span. How cost effective is your process?
We developed the material in such a way that adding the scrap tyre fibres to the concrete improves the resilience of the concrete and extends its lifespan. We also reduced the cost by using a high strength material requiring lower thickness in placement such as roads. The high resiliency of the material guarantees minimal maintenance, high durability, increased service life, and lower life-cycle cost.
It is said that polymer fibres used in concrete also bridges cracks as they form. Can you explain this phenomenon?
Polymer fibres — either extracted from tyres or the co-extruded nano-coated fibres used in the Tondebhavi Road — bond with concrete. Once a crack forms, the fibres work to bridge cracks and provide much higher resistance to crack growth. The cracks, therefore, remain narrow, do not extend with time, and in fact, can even heal themselves due to closing pressures.