To analyse the differences in the high-temperature performance of twin-screw desulphurised rubber powder/undesulphurised rubber powder composite SBS-modified asphalt and its mixes. This paper analyses the performance differences between desulphurised rubber powder composite SBS-modified asphalt (ACR/SBS), rubber powder composite SBS-modified asphalt (CR/SBS) and SBS-modified asphalt and their mixtures by multi-stress repeated creep recovery (MSCR) and submerged Hamburg rutting tests. In addition, fluorescence microscopy was used to reveal the micro-mechanisms underlying the differences in the high-temperature performance of the three asphalts. The results show that the twin-screw desulphurisation of rubber powder can significantly improve the high-temperature performance and water damage resistance of its composite-modified asphalt and mixture. The rutting depth of ACR/SBS-MA mixes was one-third and one-thirteenth of CR/SBS-MA mixes and SBS-MA mixes, respectively, under the hydrothermal coupling condition at 80 °C. The cross-linking bonds were opened during the twin-screw desulphurisation process to form a stable cross-linking network structure with SBS. The research of this thesis can lay theoretical and technical support for the promotion and application of desulphurised rubber-modified asphalt.

To investigate the rheological properties and influence mechanisms of twin-screw activated rubber composite-modified asphalt, we used SBS-modified asphalt (SBS) as the reference. Raw rubber powder composite-modified asphalt (RA/SBS) and activated rubber composite-modified asphalt (ARA/SBS) were prepared. A dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were employed to comparatively analyze the rheological characteristics of the three modified asphalts, while Fourier transform infrared spectroscopy (FTIR) and fluorescence microscopy were used to reveal the micro-mechanisms in ARA/SBS. The results showed that ARA/SBS exhibited better storage stability and low-temperature flexibility compared to SBS and RA/SBS, and ARA/SBS demonstrated lower viscosity than RA/SBS. Among the three, ARA/SBS showed significantly improved high-temperature performance. The comparison of creep stiffness S and creep rate m indicated optimal performance in ARA/SBS, confirming that twin-screw activated rubber powder could significantly enhance the low-temperature properties of modified asphalt. Microscopically, chemical reactions occurred between oxygen-containing functional groups in activated rubber and polar groups in asphalt, while a cross-linked network structure formed between activated rubber molecules and asphalt molecular chains, improving compatibility and enhancing the rheological properties of composite modified asphalt.

Objective: We investigated the contribution of oxygen and UV light to the UV aging process of warm mix asphalt (WMA). Methods: In this paper, warm mix asphalt was prepared with different aging methods (RTFOT, PAV and UV) and UV aging times (50 h, 100 h, 150 h and 200 h). The cohesion and bonding functions of WMA were tested using surface free energy theory. In addition, the UV aging functional groups of WMA were analyzed using Fourier transform infrared spectroscopy (FTIR). On this basis, the contribution of oxygen and ultraviolet light to the UV aging of WMA was analyzed using the random forest model. Results and conclusions: The results showed that UV aging had the greatest effect on the adhesion property index and functional group index of WMA, followed by PAV aging, and RTFOT aging had the least effect. With the extension of UV aging time, the adhesion and cohesion functions of WMA showed a decreasing trend, while the carbonyl index and sulfoxide index showed an increasing trend. When the UV aging time exceeded 150 h, the adhesion function and functional group index of WMA gradually tended to stabilize. The effect of UV aging on the adhesive properties of WMA was mainly due to adhesive damage. There were significant differences in the effects of oxygen isolation and light–oxygen-coupled UV aging on the adhesive properties and functional group index of WMA. In the light–oxygen-coupled UV aging of warm mix asphalt, the contribution of UV radiation was 79.9%, and the contribution of oxygen was 20.1%.

This study presents a method to more reasonably control the quality performance of activated rubber asphalt by microwave activation. Different activated rubber asphalt preparation process parameters (reaction temperature, stirring rate, and reaction time) were selected to explore the influence of different process parameters on the macroscopic properties of rubber asphalt, and a multi-indicator evaluation model was set up using the theoretical method of the RSR model to determine the optimal production process parameters. The results showed that reaction temperature had the strongest influence (gray correlation > 0.85) among production parameters, followed by stirring rate and reaction time. The optimal parameters identified were a reaction temperature of 220 °C, a stirring rate of 1000 rpm, and a reaction time of 120 min, under which the viscosity–temperature sensitivity decreased by approximately 18%, and the rutting factor (G*/sinδ) increased by over 20%, indicating significant improvements in rheological stability and high-temperature performance. The integrated evaluation approach provided reliable and practical guidance for producing high-performance activated rubber asphalt.

To investigate the contribution rates of oxygen and ultraviolet radiation to the Ultraviolet (UV) aging process of warm mix asphalt(WMA). WMA with different aging methods（RTFOT, PAV and UV）and UV aging time（50h,100h,150h and 200h）was prepared. Cohesive work and adhesive work of WMA tests were performed using surface free energy theory. In addition, The UV aging functional groups of WMA was analyzed using fourier transform infrared (FTIR). The influence laws of oxygen barrier and lightoxygen coupling conditions on the adhesion index and functional group index of WMA were explored, based on which the contribution of oxygen and ultraviolet light to the UV aging of WMA was analyzed by using the random forest model. The test results showed that UV aging had the greatest effect on the adhesion performance index and functional group index of WMA, followed by PAV aging, and RTFOT aging had the least effect. With the prolongation of UV aging time, the adhesion and cohesion functions of WMA showed a decreasing trend, while the carbonyl index and sulfoxide index showed an increasing trend. When the UV aging time exceeded 150h, the adhesion function and functional group index of WMA were gradually stabilized. The effect of UV aging on the adhesive properties of WMA was mainly due to adhesive damage. There were significant differences in the effects of oxygen isolation and light-oxygen coupled UV aging on the adhesive properties and functional group index of WMA. In the light-oxygen coupled UV aging of warm mix asphalt, the contribution of UV radiation was 79.9% and the contribution of oxygen was 20.1%.