LSM.LV – a public broadcasting of Latvia – reported on March 21, 2021 that scientists at Riga Technical University (RTU) have been looking for a solution to pave Latvia's roads with rubberized asphalt made from recycled end-of-life tires.

This summer, an experimental plot of a local highway could be paved with asphalt concrete containing rubber granules from recycled tires.

Scientists from RTU have developed and tested several new recipes for bitumen, the glue that contains rubber powder which is further used in asphalt and concrete. Road builders typically add specific polymers to bitumen so that road surface is more resilient to cracks and pits.

Latvia to experiment with paving roads with old tires. | Video by LSM.LV.

The scientists also suggest replacing the polymer in part, combining it with rubber powder from recycled end-of-life tires. As studies show, rubber-modified bitumen is competitive in terms of quality.

“The rubber can be stretched and released, and it bounces back, demonstrating flexibility effect. We cannot stretch the bitumen, it will break,” said Viktors Haritonovs, lead researcher at the RTU Road and Bridge Department. "Consequently, by supplementing the bitumen with rubber, we allow the bitumen to become more flexible, more stretchy.”

If the polymer costs €4,000 a ton, then the rubber granules are about €120 to €150, Haritonovs said. “See what the difference is in terms of prices. Therefore, it is a competitive solution,” he added.

The use of rubber in the production of asphalt is nothing new: the method has been known for 70 years, but the technologies applied are evolving. Recycled tire rubber has not been used yet in Latvia’s road construction. One of the reasons was that there was no suitable raw material and now there are several tire recycling plants that produce the needed rubber powder.

In August, the new asphalt recipe will be tested in practice, in a 1 km stretch of road. Further discussions with are taking place to start a bigger trial of the rubberized asphalt from recycled tires in the country.

Original article by LSM.LV.