Fracture Damage Properties of SBS-Modified Asphalt Mixtures Reinforced with Basalt Fiber after Freeze-Thaw Cycles Using the Acoustic Emission Approach

This paper focuses on the fracture damage characteristics of styrene-butadiene-styrene (SBS)-modified SMA-13 specimens with basalt fiber under various freeze-thaw (F-T) cycles. SBS-modified stone mastic asphalt (SMA)-13 specimens with basalt fiber were prepared, first, using the superpave gyratory compaction method. Then, asphalt mixture specimens processed with 0-21 F-T cycles were adopted for the high-temperature compression and low-temperature splitting tests. Meanwhile, the acoustic emission (AE) test was conducted to evaluate the fracture characteristics of the asphalt mixture during loading. The results showed that the AE parameters could effectively reflect the damage fracture characteristics of the asphalt mixture specimen during the high-temperature compression and low-temperature splitting processes. The fracture damage of the asphalt mixture specimens during compression or splitting are classified into three stages based on the variation of the AE signals, i.e., when the load level is below 0.1 similar to 0.2 during the first stage and the load level is 0.1-0.9 or 0.2-0.8 during the second stage. The AE signal amplitude and count show clear correlations with the compression and splitting load levels. Meanwhile, the AE signal clarifies the formation, development, and failure of internal damage for the asphalt mixture specimens during the compression and splitting processes. The intensity (value and density) of the AE signal parameters of asphalt mixture decreases with increasing F-T cycles. It is evident that the F-T cycle has a significant adverse effect on the mechanical strength of asphalt mixture, which makes asphalt mixtures more likely to cause early failure.