Workability and Improvement Evaluation of Warm-Mixed High-Content SBS Asphalt Mixtures

High-content SBS-modified asphalt has been widely used in high-grade highway pavement engineering due to its excellent mechanical properties and adaptability to heavy traffic. However, its application is hindered by high energy consumption and poor workability at elevated temperatures, which limits the development of green and efficient construction practices. In this study, on the basis of warm mix technology, a self-developed organic viscosity-reducing warm-mixed additive was incorporated to establish a warm-mixed asphalt mixture system with high-content SBS modification. With SMA-13 as the target gradation, the mixing and compaction workability was evaluated. A self-developed apparatus for mixing workability testing was used to determine the minimum mixing energy consumption as an evaluation indicator of mixing workability. Meanwhile, a gyratory compactor was used to obtain the compaction slope for quantifying compaction workability. The test results show that the representative torque value of the warm-mixed mixture at 155 ℃ is close to that of the conventional mixture at 175 ℃, with a 15.3% reduction in minimum mixing energy consumption. In the compaction test, the warm mix system at 140 ℃ achieves a slightly higher compaction slope compared to the conventional system at 160 ℃. Overall, the results demonstrate that warm mix technology enables a 20 ℃ reduction in construction temperature while significantly improving both mixing and compaction workability.