Abstract: To reveal the microscopic mechanism of silane coupling agent graft-activated waste crumb rubber, and its compatibility and interaction with the asphalt matrix. The waste crumb rubber was graft-activated with silane coupling agent KH550 in the laboratory, and its activation effect and microstructural characteristics wereexplored. Secondly, based on the molecular simulation software of Materials Studio, the monomer and blen-ding system model of asphalt and crumb rubber were constructed. The compatibility and interaction mechanism between asphalt and crumb rubber before and after grafting were analyzed through the indicators of electric dipole moment, solubility parameter, and binding energy. Finally, the simulation results were verified through segregation tests. The results show that a dense silane coupling film is formed on the surface of the waste crumb rubber after KH550 graft activation treatment. The content of C-H and O-H bond functional groups has changed significantly, indicating that KH550 has been successfully grafted onto the surface of the crumb rubber. Compared with ordinary crumb rubber, KH550 graft-activated crumb rubber exhibits stronger polarity, larger binding energy, and smaller difference in solubility parameters between rubber and asphalt, indicating better compatibility between the grafted crumb rubber and asphalt. From the analysis of molecular interaction mechanism, the hydroxyl groups at one end of the KH550 hydrolysis product molecule undergoes dehydration condensation with the hydroxyl groups on the surface of the rubber, while the 3-aminopropyl group at the other end exhibits strong physical adsorption with asphalt, effectively enhancing the compatibility of the system structure. Additionally, the segregation test results for process compatibility are consistent with the molecular simulation results for thermodynamic compatibility, further providing references for evaluating the effective methods of compatibility between activated crumb rubber and asphalt.
1 Zheng J L, Lv S T, Liu C C. Chinese Science Bulletin, 2020, 65(30), 3219(in Chinese) 郑健龙, 吕松涛, 刘超超. 科学通报, 2020, 65(30), 3219. 2 Bao D J, Qiu J H, Yao M H, et al. Materials Research and Application, 2023, 17(1), 166 (in Chinese). 宝鼎晶, 邱剑辉, 姚明辉, 等. 材料研究与应用, 2023, 17(1), 166. 3 Li D N, Leng Z, Zhang S W, et al. Resources, Conservation & Recycling, 2022, 185, 106506. 4 Lv Q, Huang W D, Zheng M, et al. Construction and Building Materials, 2022, 348, 128716. 5 Yao Z, Zhang L B, Liang P F, et al. Materials Reports, 2022, 36(16), 101(in Chinese) 姚震, 张凌波, 梁鹏飞, 等. 材料导报, 2022, 36(16), 101. 6 Lei Y, Wang H, Fini E H, et al. Construction and Building Materials, 2018, 191, 692. 7 Liang M, Xin X, Fan W, et al. Construction and Building Materials, 2015, 74, 124. 8 Xu G J, Fan J W, Ma T, et al. Materials Reports, 2022, 36(16), 5(in Chinese) 徐光霁, 范剑伟, 马涛, 等. 材料导报, 2022, 36(16), 5. 9 Ma T, Chen C L, Zhang Y, et al. China Journal of Highway and Transport, 2021, 34(10), 1(in Chinese). 马涛, 陈葱琳, 张阳, 等. 中国公路学报, 2021, 34(10), 1. 10 Xiao J J, Qiu Z M, Jin F, et al. New Chemical Materials, 2015, 43(11), 120(in Chinese). 肖建军, 邱祖民, 金斐, 等. 化工新型材料, 2015, 43(11), 120. 11 Xu O, Li M, Hou D, et al. Construction and Building Materials, 2020, 256, 119440. 12 Colom X, Falip A, Formela K, et al. Polymer Testing, 2016, 52, 200. 13 Li J, Chen Z X, Xiao F P, et al. Resources, Conservation & Recycling, 2021, 169, 105518. 14 Phiri M M, Phiri M J, Formela K, et al. Journal of Cleaner Production, 2022, 369, 133084. 15 Liu B Q, Li J, Han M Z, et al. Construction and Building Materials, 2020, 238, 117737. 16 Ou S K, Chae W B, Choi S M, et al. Journal of Materials in Civil Engineering, 2015, 27(3), 04014123-1. 17 Min Y H, Fang Y, Huang X J, et al. Applied Surface Science, 2015, 346, 497. 18 Zhang H L, Zhu C Z, Yu J Y, et al. Construction and Building Materials, 2015, 98, 735. 19 Sun L, Xin C T, Ren G L, et al. Journal of Materials in Civil Engineering, 2017, 29(3), 04016227. 20 Liu L, Liu Z H, Xiang Y, et al. Journal of Building Materials, 2017, 20(1), 150(in Chinese) 柳力, 刘朝晖, 向宇, 等. 建筑材料学报, 2017, 20(1), 150. 21 Xiang Y, Fan H J, Liu Z H, et al. Construction and Building Materials, 2020, 236, 117600. 22 Li D D, Greenfield M L. Fuel, 2014, 115, 347. 23 Guo F C, Zhang J P, Pei J Z, et al. Construction and Building Materials, 2020, 252, 118956. 24 Xu G J, Yao Y S, Ma T, et al. Construction and Building Materials, 2023, 369, 130570. 25 Huang M, Zhang H L, Gao Y, et al. International Journal of Pavement Engineering, 2021, 22(3), 319.