AC型沥青混合料车辙变形机理分析

通过某高速公路车辙病害的调查和沥青混合料技术指标的测试,采用永久变形量大和变形量小的混合料技术指标作对比分析,得出理论最大相对密度的失真将直接造成体积指标的失控。研究还表明,一个设计孔隙率和间隙率偏小且具有驼峰级配的混合料,饱和度指标对沥青用量非常敏感,沥青用量微小的变化,将导致饱和度较大的差异,很容易造成混合料软弱易塑而发生车辙,施工时也极易压实,会出现压实度、体积指标合适但混合料易塑的悖论。因此,设计时应合理选择体积指标和防止出现驼峰级配,施工控制时体积指标应与设计指标相联系,不宜一概而论。

Mechanism Analysis on AC Asphalt Mixture Rut Deformation

Through survey on rut occurred on an expressway and the tests on asphalt mixture technical index,also through the comparative analysis on the technical index of two different mixtures,of which one has larger permanent deformation and the other has smaller permanent deformation,it can be concluded that the distortion of theoretical maximum relative density directly leads to ineffective controll of the bulk index.In addition,the analysis indicates that the mixture which features smaller designed void ratio and pore ratio as well as Hump Gradation,the saturation is quite sensitive to asphalt consumption;small change of asphalt consumption would lead to bigger difference of saturation,which may make the mixture softer and not only easy to rutting but also to compaction during construction,so that wrong conclusion may be reached indicating that the compactness and bulk index are satisfactory but the mixture is quite soft and features plasticity.Therefore,reasonable bulk index should be selected and hump gradation should be avoided during the design phase.The bulk index during construction should be linked with the design index.The different cases should be considered.