Of all countries within the European Union, the Netherlands have the highest density of motorways. The maintenance costs for all these roads is extremely high. For they all have to be replaced every ten years. This is due to cracks in the asphalt. These cracks occur when the bitumen, the glue between the sand and stones in the asphalt, stops working. Nobody had ever built a system to close cracks in the pavement. Until now. The bitumen bonds can be repaired once and again, for several times, by making asphalt electrically conductive. Because asphalt concrete is not an electrically conductive material, steel wool fibers have been added. These are connected inside the asphalt concrete and create small circuits. When this new type of asphalt is heated with induction energy, the bitumen melts and that holds the road together. With help of this induction method, the lifetime of roads can be increased more than four times.
The only necessary maintenance would be needed once in two-three years, when a machine closes all the cracks that could have appeared in that period. This not only reduces the cost of the roads by more than three times, it would also dramatically reduce the number of traffic accidents that happen due to bad road conditions and furthermore it would reduce the delays and traffic jams enormously because this maintenance is much faster compared to making a
new road.
(http://www.youtube.com/watch?v=ebxiJKccgtA)
References:
1. García A., Schlangen E., van de Ven M., Quantalo L., (2009), “Electrical conductivity of asphalt mortar containing conductive fibers and fillers”, Construction and Building Materials, doi:10.1016/j.conbuildmat.2009.06.014.
2. García A., Schlangen E., van de Ven M., (2009), “Closing cracks on conductive asphalt mortar by induction heating”, Second International Conference on Self-Healing Materials, Chicago, June 28 - July.
3. García A., Schlangen E., van de Ven M., (2009), “How to make good conductive asphalt mortar”, AES - ATEMA’ 2009, Montreal.
4. García A., Schlangen E., van de Ven M., (2009), “Increasing the healing rates of asphalt concrete pavements”, 8th International Conference on Fracture and Damage Mechanics, Malta, September 8 - 10. Published in Key Engineering Materials 417, Advances in Fracture and Damage Mechanics VIII.
