Effect of Fischer-Tropsch wax on the performance of high-viscosity polymer asphalt binders

High-viscosity Polymer asphalt (HVPA) is often used as a binder in long-life, porous pavements, involving high mixing and construction temperatures to meet construction quality requirements. Warm additives can improve construction performance and reduce carbon emissions. In this article, Fischer-Tropsch wax (FTW) products with melting temperatures of 90 C and 110 C were used to modify two commercial HVPA binders. The viscosities of the warm-mix modified HVPA binders were tested at different temperatures, and the reduced construction temperatures were calculated. Mix molding experiments were used to further determine the cooling effect. FTW showed a negligible decrease in high-temperature performance, which also was proved by Marshall stability experiments on mixtures. The negative effect on low-temperature performance is significant, which makes FTW not suitable for cold regions. However, the positive effects on fatigue resistance and durability of FTW are also significant. Different HPVAs react with FTW to different degrees, and the different effects make the selection of FTW as a warm mix additive more careful. The cooling effect and low-temperature performances need to be considered comprehensively.