Abstract: In order to research the influence of material composition, temperature and loading speed on the shear performance of gussasphalt, triaxial shear test was used to test the maximum failure load and its corresponding axial deformation of gussasphalt. Based on Coulomb-Moore theory, the shear strength parameters such as cohesion c, internal friction angle φ and shear strength τ were calculated. The research results show that: For three kinds of composite modified asphalt mixtures, the shear strength of the mixture is polymer composite modification>lake asphalt composite modification>hard asphalt composite modification. The shear strength and parameters of polymer composite modified asphalt mixture are the largest and the comprehensive shear performance is the best. With the increase of the asphalt aggregate ratio, the internal friction angle is gradually decreased, and the shear strength and cohesion first increase and then decrease, reaching the maximum value respectively when the asphalt aggregate ratio is 7.8% (τ= 1.15 MPa, c=0.82 MPa）. The shear resistance of the mixtures with medium gradation is the best. When the gradation is changed from fine to coarse, the cohesion and shear strength increase at first and then decrease, and the influence is more significant. It can be seen that the shear resistance of gussasphalt with suspended dense structure depends more on the bonding effect. Temperature is the most significant factor affecting the shear performance of the mixtures, and the shear strength and cohesion gradually decrease with the increase of temperature. When the temperature rises from 25 ℃ to 60 ℃, the shear strength and cohesion decrease by 33% and 37% respectively. The internal friction angle decreases with the increase of temperature, but the change trend is not obvious. The shear resistance indexes gradually increase with the increase of the loading rate, but the trend is relatively slow. The internal friction angle has little effect on the loading rate, and the maximum difference is only 1.52°. Compared with other factors analyzed, the loading rate has no significant effect on the shear strength of the mixture.

Key words: bridge engineering; gussasphalt mixture; shear strength; triaxial shear test; cohesion; internal friction angle

摘要： 为研究材料组成、温度、加载速度等对浇注式沥青混合料抗剪性能的影响，采用三轴剪切试验，测试浇注式沥青混合料的最大破坏荷载及其对应的轴向变形，并基于库伦-摩尔理论，计算得到抗剪强度参数黏聚力c、内摩擦角φ及抗剪强度τ。研究结果表明：对三种复合改性沥青混合料，混合料抗剪强度大小为聚合物复合改性>湖沥青复合改性>硬质沥青复合改性，聚合物复合改性沥青混合料抗剪强度及参数最大，综合抗剪性能最优；随油石比增大，内摩擦角逐渐减小，抗剪强度和黏聚力先增大后减小，油石比7.8%时分别达到最大值（τ=1.15 MPa、c=0.82 MPa）；中级配下混合料抗剪性能最好，级配由细变粗时，黏聚力与抗剪强度先增大后减小，影响更为显著，可见悬浮密实型结构的浇注式沥青混合料抗剪性能更依赖于黏结作用；温度是影响混合料抗剪性能最显著的因素，抗剪强度和黏聚力随温度的升高逐渐减小，当温度从25 ℃升到60 ℃时，抗剪强度和黏聚力分别降低了33%和37%，内摩擦角随温度的升高虽也减小，但变化趋势不大；抗剪指标均随加载速率的增大逐渐变大，但趋势较缓慢，内摩擦角对加载速率几乎没有影响，最大差值仅为1.52°；相比分析的其他因素，加载速率对混合料的抗剪强度影响并不显著。

关键词: 道路工程；浇注式沥青混合料；抗剪强度；三轴剪切试验；黏聚力；内摩擦角