应力吸收结构层拉压模量差异对路面力学性能的影响

Influence of Tensile Modulus and Compressive Modulus Difference of Stress Absorbing Structural Layer on Mechanical Properties of Pavement

应力吸收结构层沥青混合料是一种沥青含量较高的热拌沥青混合料,具备较好的弯拉变形性能和抗车辙性能,且其拉伸模量与压缩模量(下文简称“拉压模量”)存在较大的差异。为研究旧水泥路面加铺中该类材料的拉压模量差异对路面结构的影响,针对其不同拉压模量的本构模型,建立32种路面结构模型进行数值模拟,分析材料的模量和厚度对路面力学性能的影响。结果显示:依据以压缩模量模型计算得到的应力吸收结构层材料的层底拉应变结果进行路面设计偏保守;应力吸收结构层材料拉压模量比的降低,对于减小层底拉应变从而降低材料疲劳引起的开裂风险是有利的;应力吸收结构层的层底拉应变与其厚度呈正相关,两种模量模式下计算得到的应变差与厚度呈正相关。

Stress absorbing structural layer asphalt mixture are hot-mix asphalt mixture with high asphalt content,which have good bending and tensile deformation properties and rutting resistance,and there are large differences between the tensile modulus and compressive modulus.In order to study the influence of tensile modulus and compressive modulus difference of this material on the pavement structure in the retrofitting of old cement pavement,the intrinsic model of this material with different tensile modulus and compressive modulus was numerically modeled and 32 pavement structure models were established for numerical simulations to analyze the influence of modulus and thickness of this material on the mechanical properties of the pavement.The results showed that:the results of pavement design are conservative in terms of the calculated sublaminar tensile strain of the stress absorbing structural layer material obtained from the compressive modulus model;the reduction of the tensile to compressive modulus ratio of the stress absorbing structural layer material is beneficial to reduce the sublaminar tensile strain and thus the risk of fatigue cracking of the material;the sublaminar tensile strain of the stress absorbing structural layer is positively correlated with its thickness,and the difference in the calculated strain between the two modulus models is positively related to the thickness.