Abstract
Acoustic emission (AE), as a nondestructive testing (NDT) and real-time monitoring technique, could characterize the damage evolution and fracture behavior of materials. The primary objective of this paper was to investigate the improvement mechanism of steel slag on the low-temperature fracture behavior of permeable asphalt mixtures (PAM). Firstly, steel slag coarse aggregates were used to replace basalt coarse aggregates with equal volume at different levels (0%, 25%, 50%, 75%, and 100%). Then, the low-temperature splitting test with slow loading was used to obtain steady crack growth, and the crack initiation and propagation of specimens were monitored by AE technique in real time. From the low-temperature splitting test results, SS-100 (permeable asphalt mixtures with 100% steel slag) has the optimal low-temperature cracking resistance. Therefore, the difference of fracture behavior between the control group (permeable asphalt mixtures without steel slag) and SS-100 was mainly discussed. From the AE test results, a slight bottom-up trend of sentinel function was founded in the 0.6–0.9 displacement level for SS-100, which is different from the control group. Furthermore, the fracture stages of the control group and SS-100 could be divided based on cumulative RA and cumulative AF curves. The incorporation of 100% steel slag reduced the shear events and restrained the growth of shear cracking of the specimen in the macro-crack stage. Finally, the considerable drops of three kinds of b-values in the final phase were found in the control group, but significant repeated fluctuations in SS-100. In short, the fracture behavior of PAM under low temperature was significantly improved after adding 100% steel slag.
Highlights
Permeable asphalt pavement refers to the fully permeable pavement in which rainwater permeates into the ground through subgrade or discharges through buried drainage facilities [1]
The results showed that the addition of steel slag significantly improves the permeability, skid resistance, durability, and rutting resistance of Permeable asphalt mixtures (PAM)
The results revealed that the energy distribution of Acoustic emission (AE) waveform can be used to characterize the irreversible damage mechanism associated with Kaiser and the Felicity effects
Summary
Permeable asphalt pavement refers to the fully permeable pavement in which rainwater permeates into the ground through subgrade or discharges through buried drainage facilities [1]. Permeable asphalt mixtures (PAM), as sustainable pavement materials, are credited with various environmental benefits, such as urban floods alleviation by promoting the natural infiltration of rainwater, underground water quality improvement by treating pollutants, and heat-island effect mitigation by facilitating heat transfer processes [3,4]. Their poor low-temperature cracking resistance has become a barrier against the wide application of PAM [5,6]. Steel slag is the main byproduct of the steel manufacturing industry [7]. According to the data from the World Steel Association, the crude steel production output of China in 2019 has reached
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