大粒径透水沥青混合料抗反射裂缝影响因素及仿真研究

    Influence Factors and Simulation of Anti-reflection Crack of Large Stone Porous Asphalt Mixes

    • 摘要: 为了定量评价大粒径透水沥青混合料(large stone porous asphalt mixes,LSPM)的抗反射裂缝性能,开展了不同级配、试样高度和空隙率条件下的室内路面抗裂缝性能测试(overlay tester,OT)试验,分别采用最大荷载损失率、第一周期荷载损失率和50%荷载损失率加载周期数3个指标进行评价,建立了基于试样高度和空隙率的抗反射裂缝疲劳寿命预估模型;进而开展OT试验的内聚力模型有限元分析,对不同因素影响抗反射裂缝的试验过程开展研究.结果表明:荷载损失率可以通过对数模型进行预估;采用第一周期荷载损失率和50%荷载损失率下加载周期数更能有效地评估不同级配LSPM-30的抗反射裂缝性能;试样孔隙率对LSPM-30抗反射裂缝具有更显著影响,推荐LSPM-30的OT试验抗反射裂缝试样高度不小于70 mm;数值分析结果表明裂缝是由于裂尖的拉应力/应变较大而诱发的张开型裂缝,主要分布于沥青胶结料内及沥青胶结料和集料的界面处.

       

      Abstract: Overlay tester (OT) tests were carried out with different gradations, sample heights and air void to quantitatively evaluate anti-reflection crack performance of large stone porous asphalt mixes (LSPM) in this paper. Maximum load loss rate, first cycle load loss rate and loading cycle of 50% load loss rate were adopted for analysis, and anti-reflection crack prediction models based on sample height and air void were put forward. Finite element analysis of cohesion zone model in OT test was carried out to study the mechanism of different factors affecting anti-reflection crack. Results show that the load loss rate can be estimated by the natural logarithm model. The anti-reflection crack performance of LSPM-30 with different gradations can be more effectively evaluated with first cycle load loss rate and loading cycles of 50% load loss rate. The air void of samples has a more significant influence on the anti-reflection crack of LSPM-30 than that of the height, and the height of the anti-reflection crack samples in OT test is recommended to be no less than 70 mm in this study. The results of numerical analysis show that the crack type is I crack induced by the higher tensile stress/strain at the crack tip, which is mainly distributed in the interior of asphalt mortar and the interface between asphalt mortar and aggregate.

       

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