Researchers from the Australian university RMIT have developed an additive for asphalt mixture, which significantly increases its protection from ultraviolet radiation and overheating in the sun, Techkult reported.

For the hot Australian climate the problem is very urgent, and there, as well as in many places in the world, there is a problem of disposal of old tires. Scientists offered to grind them into rubber crumbs and add to asphalt.

The idea was born after another experiment, in which the addition of rubber crumbs increased the heat resistance of concrete. Researchers have arranged an experiment with three different compositions of asphalt, which were added 7,5%, 15% and 22,5% of crumb. Samples for a month and a half were placed in the machine to simulate the impact of solar radiation during the year. Measurements of the chemical and mechanical properties of the samples showed that they withstood the radiation and heat much better than conventional asphalt.

They found that the higher the crumb concentration in the asphalt, the better it resisted the heat. However, when the coefficient exceeds 22%, the degradation of strength characteristics begins and the road surface becomes vulnerable to mechanical damage. The optimal range of 18-22% was experimentally determined when the asphalt lifetime under the scorching sun actually doubles. And at the same time, the problem of recycling old tires is solved.