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In order to further explore the performance of mixture with waste tire rubber (WTR) and amorphous poly alpha olefin (APAO) modified asphalt, the 12%WTR+4%APAO and 15%WTR+4%APAO modified asphalt mixtures were selected as research objectives. The asphalt mixtures with matrix asphalt, WTR modified asphalt, and SBS modified asphalt were prepared for comparative analysis. Through the mixture design, the optimum asphalt-aggregate ratio of five asphalt mixtures was determined respectively. The volumetric parameters and resilient modulus were studied. The laboratory performances were studied by standard Marshall stability test, wheel tracking test, immersion Marshall test, freeze–thaw splitting test, indirect tensile strength test, indirect tensile fatigue test, and Marshall stability after long-term aging test. Compared with the other three asphalt mixtures, the results showed that the 12% WTR+4%APAO modified asphalt mixture had the highest Marshall stability and high-temperature performance. While the 15% WTR+4%APAO modified asphalt mixture had better permanent deformation resistance at high temperatures, moisture stability, aging resistance, and relatively good fatigue performance. The statistical hypothesis test results also confirmed that WTR/APAO modified asphalt has a significant effect on mechanical properties. Based on the results of various performance, the 15% WTR+4% APAO was the optimal content for asphalt mixture. [ABSTRACT FROM AUTHOR]

• WTR/APAO modified asphalt was applied to the stress-absorption interlayer. • Physical, durability, shear resistance, reflection cracking resistance were investigated. • OT and Paris' Law were used to evaluate the reflection cracking resistance of the stress-absorption interlayer. Stress-absorption interlayer (SAI) is one of the most important methods to prevent reflection cracking. This paper analyzed the properties of SAI with the waste tire rubber (WTR) and amorphous ploy alpha olefin (APAO) complex modified asphalt binder. Research found that WTR/APAO modified asphalt works excellently as a binder in SAI. The SAI with base asphalt, WTR/APAO, WTR and SBS modified asphalt mixture were prepared for comparative analysis. The mechanical properties and durability of four SAIs were determined using Marshall stability, Indirect tensile (IDT) strength, immersion Marshall and Marshall stability after aging procedure. The bond strength and shear resistance of three SAIs with modified asphalt were determined using slant shear tests under different conditions. The overlay tests (OT) were used to characterize the fatigue and anti-reflection cracking performance. Besides, the Paris' Law was used to characterize the fracture properties based on OT. Research found that WTR/APAO SAI had the strongest high temperature stability, deformation resistance, bond strength and shear resistance. WTR/APAO and SBS SAIs had excellent water stability and anti-aging performance. WTR/APAO SAI had the highest bond strength at both high and normal temperatures. The OT number of cycles of all three SAIs reached 1200 times. This indicator showed that all three SAIs had excellent fatigue and anti-reflection cracking performance. Further research found that the fracture properties n in Paris' Law showed that WTR/APAO and SBS SAIs had better cracking resistance. The addition of APAO improved the cracking resistance of WTR SAI. [ABSTRACT FROM AUTHOR]

• The aging resistance of WTR/APAO modified asphalt and asphalt mixture were investigated. • The evaluation indexes of the effect of long-term aging on performance was proposed. • The incorporation of WTR and APAO improves the resistance of asphalt to long-term aging. • The high and low temperature performance of 15%WTR + 4%APAO asphalt mixture after long-term aging are better than SBS asphalt mixture. The aging resistance of asphalt mixture has an important impact on the long-term quality and service life of asphalt pavements. This research aims at studying the effects of long-term aging on waste tire rubber (WTR) and amorphous poly alpha olefin (APAO) modified asphalt binder and mixtures. The prepared compounds included, 12%WTR + 4%APAO and 15%WTR + 4%APAO modified asphalts, were used as experimental objects. Base asphalt binder (70 penetration grade), 15%WTR modified asphalt and styrene–butadiene-styrene (SBS) modified asphalt were the reference objects. First, pressure aging vessel (PAV) and long-term oven aging (LTOA) were used to simulate the long-term aging of asphalt binder and mixture, respectively. Secondly, the performance tests of asphalt binder and mixture were carried out, and the evaluation indexes of the effects of long-term aging on performance were proposed. For the asphalt binder, the results show that the incorporation of WTR and APAO significantly improves the post-aging conventional properties, rheological properties and fatigue properties. The Fourier transform infrared spectroscopy (FTIR) results were found to correlate to the physical tests results. In the asphalt mixture part, the results show that 15%WTR + 4%APAO modified mixture has better high temperature and fatigue performance after aging, among the rubber-based asphalt mixtures. The low-temperature performance of WTR/APAO asphalt mixture was not compromised after aging. Compared with the SBS modified asphalt mixture, the high and low-temperature performance of 15%WTR + 4%APAO asphalt mixture after aging are better. Overall, 15%WTR+4% APAO asphalt mixture has better advantages to counteract the influence of oxidative aging. [ABSTRACT FROM AUTHOR]