A professor at Delft University of Technology has come up with a way to make self-healing roads – with a little help from microwaves. Erik Schlangen is proposing to mix asphalt with tiny fragments of steel wool, of the kind used to scour pans. The purpose of the steel is not to reinforce the asphalt, but to heat up when subject to microwave radiation. Most roads in the Netherlands are constructed using porous asphalt. The spaces in the pavement structure help to absorb sound and water, making Dutch roads dryer and quieter than those built with more solid bitumen.
However, the gaps also make the structure more vulnerable to erosion and weathering. This leads to the formation of microscopic cracks in the bitumen that holds the aggregate together. The result is progressive “ravelling”, and eventually the formation of potholes and loose stones that can damage vehicles using the road.
Schlangen’s idea is to add steel so that the road is easier to heat by induction. When it is heated, the asphalt melts and the microscopic cracks are filled in and hold the aggregate in place.
The Dutch government donated a 400m stretch of the A58 as a test bed for Schlangen’s concept. Research conducted on samples from that pavement have suggested that the life of a road can be doubled if it is melted once every four years.
Image caption: Researcher develops simple trick to make roads “self-healing”
Image source: Interesting Engineering