Strength test results of semi-circular specimens.

To enhance the high-temperature stability, low-temperature crack resistance, moisture susceptibility, and fatigue life of asphalt mixtures, this study systematically investigates the effects of Zhongmao Modifier (ZM), a solid granular direct-to-asphalt polymer–resin additive produced by Zhongmao Company (Shenyang, China), dosage and mixing process parameters on the pavement performance of asphalt mixtures and elucidates the underlying mechanisms. Orthogonal experiments determined the optimal mixing parameters as a mixing temperature of 170°C, dry mixing time of 180 s, and wet mixing time of 240 s. Experimental results show that the ZM modifier significantly improves the dynamic stability and rutting resistance of the mixture, with dynamic stability increasing to 5245 and rut depth decreasing to 2.26 mm at a dosage of 0.5%. The low-temperature flexural strain increases while the bending stiffness decreases, indicating improved crack resistance. In terms of moisture stability, both the retained stability and freeze–thaw splitting strength ratio outperform those of the base asphalt, reaching 88% and 90%, respectively. Fatigue test results reveal that the ZM modifier markedly extends fatigue life, with a maximum increase of 128.9%, and reduces fatigue sensitivity to the stress ratio. Displacement evolution analysis indicates that the modifier enhances inter-aggregate bonding, increases failure displacement, prolongs the stable phase, and significantly improves overall durability. Mechanistic analysis suggests that the polymer–resin components of the ZM modifier form a stable elastic network within the asphalt matrix and strengthen the interfacial bonding between asphalt and aggregates, thereby improving high-temperature stability and durability while maintaining low-temperature flexibility. The findings provide theoretical support and practical guidance for the broader application of ZM-modified asphalt mixtures in real-world pavement engineering, particularly for enhancing the performance and service life of road surfaces under varying environmental conditions.

为提升沥青混合料的高温稳定性、低温抗裂性、水稳定性与疲劳寿命，本研究系统探究了由中国沈阳中茂公司生产的固态颗粒状直接掺加型聚合物-树脂类添加剂——中茂改性剂（Zhongmao Modifier，ZM）的掺量与拌和工艺参数对沥青混合料路面性能的影响，并阐明了其作用机理。本研究通过正交试验确定了最优拌和工艺参数：拌和温度170℃，干拌时长180s，湿拌时长240s。试验结果表明，当ZM改性剂掺量为0.5%时，混合料的动稳定度提升至5245，车辙深度降至2.26mm，显著改善了其动稳定度与抗车辙性能。低温弯曲应变提升且弯曲劲度模量降低，表明混合料的抗裂性能得到优化。在水稳定性能方面，残留稳定度与冻融劈裂强度比均优于基质沥青混合料，分别达到88%与90%。疲劳试验结果显示，ZM改性剂可显著延长混合料的疲劳寿命，最大增幅达128.9%，同时降低了混合料对应力比的疲劳敏感性。位移演化分析表明，该改性剂可强化集料间的粘结作用，提升破坏位移，延长稳定阶段，显著改善混合料的整体耐久性。机理分析表明，ZM改性剂中的聚合物-树脂组分可在沥青基体中形成稳定的弹性网络，并强化沥青与集料之间的界面粘结，从而在保持低温柔韧性的同时，提升混合料的高温稳定性与耐久性。本研究成果可为ZM改性沥青混合料在实际路面工程中的大规模推广应用提供理论支撑与实践指导，尤其有助于在多变环境条件下提升路面的使用性能与服役寿命。