Researchers from the Australian University RMIT worked on the problem. They developed an additive for the asphalt mixture, which significantly increases its protection against ultraviolet radiation and overheating in the sun.

New asphalt recipe

• It is worth noting that the problem of sun exposure to asphalt is very important for the hot Australian climate. In some areas the temperature can exceed 40 degrees. The absolute maximum recorded reached 53.1 degrees.
• In addition, as in many parts of the world, there is a problem of discarding old tires.
• Therefore, the scientists decided to combine the solutions of these two problems and offered to grind tires into rubber crumbs and add to asphalt.
• The idea was born after another experiment where the addition of rubber crumbs increased the heat resistance of concrete.
• The researchers conducted an experiment with three different compositions of asphalt with added crumbs of 7.5%, 15% and 22.5%.
• The samples were placed in a special device to simulate the effects of solar radiation.
• Measurements of the chemical and mechanical properties of the samples showed that they withstand irradiation and heat much better than normal asphalt.
• After one and a half months of continuous irradiation on the UV apparatus, which is equivalent to about a year’s worth of UV radiation in Melbourne, 50 percent less damage from ultraviolet light than conventional bitumen was found.

However, when the coefficient is exceeded by 22 percent, a loss of strength begins – on the contrary, the road surface becomes vulnerable to mechanical damage. Experimentally, the optimal range of 18-22 percent was determined, in which the service life of asphalt actually doubles under the scorching sun.

At the same time, the task of discarding old tires is solved. Used tires cannot be exported to Australia, so there is an urgent need for new methods of recycling locally. According to the source, there were around 450,000 tons of used tires in Australia in 2021. About 70 percent of these were recycled.