In addition, the aging of asphalt mixtures could also affect the crack resistance of asphalt mixtures. Therefore, this paper aims to use this test to study the crack resistance of SMA-13 asphalt mixtures and to explore the effects of ARA on the anti-crack ability of the mixtures. This paper adopted this test to reflect the crack resistance of asphalt mixtures and chose two indexes, W initial and CT Index, to represent the anti-crack ability of SMA-13 asphalt mixtures in terms of crack formation and the propagation stage. It has two stages, namely the crack formation stage and the crack propagation stage. The IDEAL-CT test is a method to reveal the anti-crack ability of asphalt mixtures. Research about using ARA and polyethylene (PE) together in an asphalt mixture was also conducted, and a good weight content combination of ARA and PE (0.2% and 0.5%, respectively), which could have a very good enhancement effect on the mixture, was also suggested. ARA could comprehensively enhance all the properties of the SMA-16 asphalt mixtures, such as high- and low-temperature performances. For instance, ARA could help to increase the ductility and other properties of asphalt mortar and the rutting resistance of asphalt mixtures. Anti-rut agents are a kind of polymer additive used in road construction to enhance the properties of asphalt mixtures. Therefore, lignin fiber is now widely used in SMA-13 asphalt mixtures to absorb the asphalt in the mixtures. The oil–aggregate ratio of SMA mixtures are often relatively higher than those of normal mixtures. In engineering practice, stone-matrix asphalt, with a 13-mm nominal maximum aggregate size (SMA-13) asphalt mixture, is a type of skeleton dense graded mixture and is now widely used in many roads that require better road performance to make driving safer and smoother. Micro cracks are usually seen as the initial distress because they can often result in stress concentration phenomenon in pavement structures, which can cause more serious problems, such as bigger cracks, etc. Nowadays, pavements are facing more and more distress due to the fact that the increasing number of vehicles or loads on roads cause asphalt mixtures bear more inner stress, which causes the tendency towards experiencing distress, especially when mixtures are put through the process of aging after being put into service. The FTIR parameters selected from the grey correlation analysis could be used to well predict the anti-crack ability of the asphalt mixtures. After conducting a series of tests, the results showed that the aging process could well affect the crack resistance of the test samples and the peak areas of the asphalt extracted from the mixtures. Grey correlation analysis was adopted to choose the most suitable FTIR spectrum parameters to derive the prediction models of W initial and CT Index under different aging degrees. The peak areas of the FTIR spectrum were utilized to reveal the chemical properties of the asphalt material inside the SMA-13 asphalt mixtures, with and without ARA under different aging degrees. The fracture formation work (W initial) and cracking index (CT Index) in the IDEAL-CT test were adopted to reflect the cracking ability of the asphalt mixtures in both the crack formation stage and the crack propagation stage. The test samples were prepared using the specifications listed by AASHTO. A convenient testing method to predict the anti-crack ability of the mixtures in a road was also derived in this study. IDEAL-CT test and Fourier transform infrared (FTIR) spectroscopy were utilized to analyze the relationships between the crack resistance of LFSMA-13, with and without ARA, and the parameters of the FTIR spectrum of the asphalt extracted from the test samples. This paper aims to better analyze the crack resistance of lignin fiber reinforced SMA-13 (LFSMA-13) asphalt mixtures, with and without polymer anti-rut agent (ARA), under different aging degrees.
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