A method to make asphalt 30-40% stronger has been developed in Russia

Scientists from Perm Polytechnic have proposed a method to increase the strength of road pavement. Researchers have developed an asphalt composition with the addition of natural chrysotile asbestos fibers. According to the press service of PNIPU, such an additive can slow down pavement degradation and increase its strength by 30-40%.

Currently, various methods are used to strengthen asphalt, but they have limitations. Most solutions are either too expensive or not effective enough. Synthetic fibers are considered a promising option, but they are costly, require special equipment, and have poor adhesion to bitumen. There is also a cheaper alternative – cellulose threads, but they are susceptible to water.

Chrysotile asbestos, according to researchers, can be a more convenient option. It is a natural mineral consisting of very thin, flexible fibers, similar to microscopic threads. Such particles are strong, do not melt even at temperatures up to 1500 ℃, and adhere well to bitumen.

In nature, chrysotile asbestos forms within serpentinites – special mineral bodies that form deep underground at high temperatures and pressures. In Russia, the main deposits of this mineral are located in the Sverdlovsk and Orenburg regions, in the south of the Krasnoyarsk Krai, and in the Republic of Tyva.

In total, researchers manufactured and tested 243 samples. Each of them was tested for strength at temperatures from 0 to 50 ℃.

In addition to strength, scientists evaluated the water resistance, shear resistance, and crack resistance of the material. After analyzing the data, they determined the combination of components at which strength and water resistance reach their maximum.

According to Konstantin Pugin, Professor of the Department of "Automobiles and Technological Machines" at PNIPU, Doctor of Technical Sciences, the best result was shown by a mixture with 1.2–1.8% chrysotile asbestos fibers and 5.9–7.2% bitumen. When heated to 50 ℃, the compressive strength of such a composition increased by 30–40% compared to conventional unreinforced mixtures.

The water resistance of the material reached 95–100%. This means that the pavement should not lose strength after rains or soften from moisture. At the same time, the crack resistance remained within acceptable limits, meaning the material should not degrade in frosts.