橡塑改性沥青路面top-down开裂性能分析

Analysis on top-down cracking resistance of rubber-plastic modified asphalt pavement

通过劈裂试验、三轴重复荷载试验和小梁弯曲试验对比了橡塑改性沥青混合料与SBS改性沥青混合料的性能,通过构建有限元模型分析了动荷载作用下沥青路面上面层裂缝的应力变化规律。结果表明,橡塑改性沥青混合料的抗拉性能与高温抗变形性能优于SBS改性沥青混合料,橡塑改性沥青可提高沥青混凝土路面的抗变形能力;橡塑改性沥青混合料的低温抗裂性能优于SBS改性沥青混合料,前者可提高沥青路面抗top-down裂缝开裂性能;在动荷载作用下,沥青路面结构层中的上面层拉应力逐渐增加,导致沥青路面发生top-down裂缝开裂,橡塑改性沥青混合料可增加上面层破坏时的最大拉应力,从而降低沥青路面发生top-down裂缝开裂的可能性。

The properties of rubber-plastic modified asphalt mixture and SBS modified asphalt mixture were compared by splitting test,triaxial repeated load test and small beam bending test,and the stress variation law of the upper layer cracks on asphalt pavement under dynamic load was analyzed by constructing finite element model.The results showed that tensile property and high-temperature deformation resistance of rubber-plastic modified asphalt mixture were better than those of SBS modified asphalt mixture,and rubber-plastic modified asphalt could improve deformation resistance of asphalt concrete pavement.Low-temperature cracking resistance of rubber-plastic modified asphalt mixture was better than that of SBS modified asphalt mixture,and the former could improve the top-down cracking resistance of asphalt pavement.Under the action of dynamic load,the tensile stress of the upper layer in the structural layer of asphalt pavement increased gradually,leading to the cracking of top-down crack of asphalt pavement,and rubber-plastic modified asphalt mixture could increase the maximum tensile stress during the failure of the upper layer,resulting in the reduction in the cracking possibility of top-down crack of asphalt pavement.