Every year European roads are built and repaired to the tune of several billion Euros.
Intensive efforts are underway all over the world to get ‘more road for your money’ by developing better methods for both design and quality control of materials. One problem is that today there are no good methods for checking how robustly and safely the roads were built. Therefore they often don’t last as long as they were supposed to and more money has to go to road construction.
But now a young scientist has developed a method where sound waves can reveal what a road looks like underneath and thereby show whether it is being properly built. According to the Swedish Road Administration, the method, which is expected to become the new standard, may entail major quality enhancements and cost savings.
Damage to bridges, tunnels, dams, and nuclear power plants can be uncovered using this technology, and dangerous accidents can thereby be prevented. Today most prognoses are based on educated guesses from previous experience, which often prove to be wrong. Since a road consists of many different materials – gravel, bitumen, air, water – it’s difficult to predict how it will respond to future traffic and environmental loads. Because roads, unlike buildings, for instance, are ‘built into’ the ground, it’s hard to inspect them visually.
“But with sound waves, roughly as with x-rays and ultrasound, you can obtain information about the composition and stiffness of the material on a computer screen. This allows you to monitor whether work is being done properly, thus ensuring that the road will last as long and withstand loads as well as projected. Today inspectors typically have to drill cores and break up asphalt and concrete samples, instead of using this non-destructive type of testing,”