Highways England, Costain and the University of Cambridge have recently been awarded funding from the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation, to investigate intelligent road repair. The idea is that these clever roads will not only sense that they are damaged, they will heal themselves too.
Although this may all sound rather sci-fi, such developments are not as fanciful as they seem. Researchers in academic institutions around the world are already at work on self-healing highway materials as well as sensors that can be embedded in the road and transmitting data.
The research will also look at how to use ‘digital twins’ – a much-used phrase which usually means a digital representation of a live asset, in this case a road, which is linked to its ‘living’ twin by data flows in both directions. Data could include traffic flow information, temperature measurements and feedback from sensors in structures, or in the road itself. Early identification of damage inside a road pavement, before it became visible, would allow it to be quickly repaired and also help highway engineers understand why some roads perform better than others and then make future design decisions accordingly.
There are several possibilities for how road materials could become self-healing. Tiny capsules could be included in the mix that would break with strain to release their contents and seal up micro-cracks before they can grow up to become larger cracks or potholes. In asphalt-paved roads, the healing material would be bitumen based.
Researchers at the Delft University of Technology have invented a different version of self-healing roads, with several already laid by contractor Heijmans in the Netherlands. Tiny steel fibres are mixed into the asphalt and then every few years, an induction machine is driven across the road. Eddy currents in the tiny steel wires heat them up which in turn heats up the bitumen which runs into tiny cracks.
Sensor technology is already well-advanced too. Sensors can be self-powered, harvesting mechanical energy from traffic loads. They can measure a wide range of parameters such as moisture, pressure, strain and temperature and communicate their information wirelessly to a node which then transmits the information on for analysis and action.
Certain states in the US have been working on embedded sensor technology for decades. There are test sections in China and in France – as well as in the US. A system called PEGASE, developed by the French institute of science and technology for roads, IFSTTAR, is already licensed by A3IP, a French company which specialises in electronics and embedded sensors.
The intelligent road repairs project was one of eight research projects which together will share around £60m funding. The other projects include using robots and AI to carry out maintenance and repair to offshore structures, creating synthetic diamonds, and decarbonising acrylic polymers which are used in a range of applications including in paints and coatings.
Thermal Road Repairs is a green technology company which supplies systems to improve the quality, cost and time efficiency of road repairs and paving – at a far lower environmental cost than traditional methods. We invest significantly in R&D, to create new technologies and to continuously improve our existing ones.
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Details of ESPRC grant
Delft University of Technology research
Review of embedded sensor technology