Behavioural mechanism of SBR, LDPE, and SBS modified bituminous mixtures

Increased heavy-vehicle traffic, higher traffic volumes, and temperature changes lead to distresses such as stripping, rutting, fatigue cracks in asphalt pavements, increasing the cost of road maintenance. Therefore, it is inevitable that the properties of bitumen and asphalt mixtures must be improved. Polymer modification is one of the methods to improve bitumen properties. In the present paper, styrene butadiene styrene (SBS), styrene-butadiene rubber (SBR), and low-density polyethylene (LDPE), along with Sasobit wax, were used to modify the bitumen. For that purpose, we used tests, including conventional bitumen tests and linear amplitude sweep (LAS) tests. The results of the present study showed that the polymer mentioned above improves the rutting index of the base bitumen. Based on the bending beam test results, polymer additives and Sasobit have no positive effect on the low-temperature performance of the base bitumen. The LAS test results were used to compare PMBs' fatigue performance, and it was evident that SBR had the most significant effect on increasing the fatigue life of the base bitumen. In the meantime, Sasobit increases the fatigue life of PMBs at high strain levels.