Method of road quality appraisal by sound waves

Each year, Europe spends billions of euros to build and repair roads. People are making constant efforts to minimize the cost of road construction by developing more optimal methods in both design and quality verification of materials. One problem is that there are no effective measures to check the stability and safety of the road. Therefore, the current roads do not exist as long as one expected, the construction still consumes a lot of society's money.

Now, a young scientist has developed a method to use sound waves to assess the condition of the road and whether the construction of the road is standard. According to the Swiss Road Administration, this method is expected to become a new standard, bringing significant improvements in quality and cost savings.

Using this measure, one can detect damage in bridges, tunnels, dams, nuclear plants. Therefore, unfortunate accidents can be limited. Today, most guesses are based on the theory drawn from previous cases. The accuracy of this measure is usually not high. A road built from a variety of materials: gravel, asphalt, air, water so it is difficult to predict how it will react to future traffic and environmental loads. Unlike a building, the road is partially underground, so it is difficult to check if only with the naked eye.

Now, a young scientist has developed a method to use sound waves to assess the condition of the road and whether the construction of the road is standard. (Photo: Wikimedia)

Nils Rydén, researcher in mechanical geology at the Department of Mechanical Engineering, Lund University, who developed the technology, said: 'Like X-rays and ultrasound, sound waves indicate information on texture and solidity of materials on a computer screen ".

"This allows you to check whether the building is being built well, so ensuring the road will have the same lifespan and load as the design. Today, inspectors often have to drill down. under the road, smashing the asphalt and concrete specimens The inspection method without breaking anything is still very new. '

According to Nils Rydén, there are roads that only last a few years. The reason may be because the material is not well compressed, because the road bed is too weak or because of construction in rainy conditions. Such errors are not detected during the last inspection.

Most of the country's facilities were built 40 to 50 years ago. Now they need to be repaired, partly due to degradation and the other part is because the size and standards are obsolete. Time has passed and the problem is emerging as to how long these structures will last. The concrete foundation of the Swiss atomic nuclear plant is in the same situation. There are no measures to check and verify whether they are in good condition or not.

Over the past few years, Nils Rydén has been very busy with his research and with consulting with the Road Administration Department, public and private agencies build their own technology application in accordance with certain goals. He said: 'A bridge cannot collapse into the ground. Just like the safety of bridges or hydropower plants, there have actually been collapses in the US and Russia. '

Nils Rydén had the idea of ​​experimenting with sound road quality appraisals when he wrote his master's thesis in 2000. At the same time, there were similar projects being conducted abroad, for example. in U.S.A. However, according to him, this Swiss method is the most advanced technology today.Earlier, sound was used to test supplies in the automotive and aircraft industry, searching for oil and underground gas.

Briefly about technology to use sound waves

This new technology is based on measuring the dispersion of sound waves. Similar to ultrasound in medicine, the purpose of this exercise is to identify the solidness and thickness of the construction material, or cracks if any . The speed of sound waves is directly related. to the solidity of the material. Differences in solids can be used to measure the thickness of layers and detect undesirable damage to the naked eye. To measure, people use sound waves with low frequencies, about 50 - 10,000 Hz. Waves with frequencies above 20,000 Hz are often referred to as ultrasound waves. It is not possible to use ultrasound in this technology because the ultrasound will disappear right away in a few (1/10 meter) asphalt and concrete. X-rays can also be used for concrete, but they are extremely expensive and complex compared to sound waves.