Rheological properties and microscopic characterization of high viscosity asphalt with different warm mixing agents

The pursuit of low carbon and clean sustainable development in road construction is imperative, and warm mix asphalt technology can help the transition from traditional high carbon emission paving materials to cleaner paving materials, thereby promoting the realization of sustainable development of road materials. The objective of this study is to examine the impact patterns of USP (a novel warm-mix additive) and Sasobit, both as individual entities and in combination, on the rheological and conventional characteristics of high viscosity asphalt. Additionally, the study seeks to delve into the mechanisms of action underlying these two distinct categories of warm-mix additives. The results of the research indicate that both warm-mix additives are effective in reducing temperatures when used alone or in combination. When used alone, USP shows significant advantages in low temperature performance, superior to both conventional hot mix asphalt and Sasobit warm-mix asphalt. The high temperature performance of USP modified asphalt is closely related to its dosage. On the other hand, the use of Sasobit alone can improve the high-temperature performance and creep recovery properties of high viscosity asphalt, but results in a decrease in low-temperature performance. When USP is blended with Sasobit, the resulting asphalt exhibits both good high and low temperature performance, with a significant improvement in aging resistance observed in the 5% USP and 2.5% Sasobit group. In conclusion, in order to ensure that warm-mix additives have a beneficial effect on the properties of high viscosity asphalt, the combined use of multiple warm-mix additives can be considered comprehensively to achieve a balance between low carbon emissions and excellent performance.