西北山区长大纵坡沥青路面层间抗剪切疲劳衰减与失效机制研究

It is an urgent problem on pavement structure that cutting slippage, folding, U-shaped cracking and other diseases with large longitudinal slope has become increasingly prominent in the northwest mountain due to deteriorating performance of anti-shearing fatigue at interlayer. However, its failing mechanism has not been showed. By using Fourier Transform Infrared Spectroscopy (FTIR) and Dynamic Shear Rheological (DSR), viscoelastic shear parameters and shear resistance effect of sticking materials under freeze-thaw cycle are analyzed based on Time-temperature Conversion Rule. According to contact models under compression-shear load of "Three Material and Two Interfaces" and modified Mohr-Coulomb shear strength theory, it is discussed the relationship of continuous stress function, straight lines of clearance and total displacements with non-Hertz contacting theory of elastic layer board. A modal threshold of contact boundary is put forward and combined shear strengths in cases of non-delamination, partial delamination and complete delamination of contacting models are established. Then oblique shear fatigue experiments in control of different shear stresses and freeze-thaw cycles are done to set up prediction models of anti-shearing fatigue life-span and to reveal the deteriorating and failing mechanism of anti-shearing fatigue. This research helps for design method of asphalt pavement, interlayer treatments and traffic control with large longitudinal slope in northwest mountain.

西北山区长大纵坡沥青路面层间抗剪切疲劳性能衰减导致路面结构出现推移、拥包以及U型裂缝等病害日益突出，已成为一个亟待解决的问题，但其失效机制尚未阐明。项目拟采用现代傅里叶变换红外光谱（FTIR）和动态剪切流变（DSR）技术相结合，基于时间温度换算法则研究冻融前后粘层材料粘弹剪切参数与抗剪切阻力效应；基于“三材两界面”压剪接触模态与修正莫尔-库伦抗剪强度理论，探求弹性层状板非Hertz法向接触理论中接触面内连续应力函数和间隙等直线与总位移的关系，确定接触界面模态阀值，建立非脱层、部分脱层和完全脱层接触模态下的联合抗剪强度；开展不同剪应力水平控制下斜剪疲劳试验，构建冻融循环影响下不同界面层间抗剪切疲劳寿命预测模型，揭示沥青路面层间抗剪切疲劳衰减与失效机制，提出沥青面层层间抗剪切疲劳对策。研究成果为西北山区长大纵坡沥青路面结构设计方法、层间处理措施以及交通管制提供理论和技术支撑。

长大纵坡沥青路面层间抗剪切疲劳性能衰减导致路面结构出现推移、拥包以及U型裂缝等病害在西北山区日益突出，已成为一个亟待解决的问题。本项目通过联合应用现代傅里叶变换红外光谱（FTIR）和动态剪切流变（DSR）测试技术，探讨层间粘结材料动粘弹剪切特性参数分析与化学组分变化关系；基于压剪接触模态、接触力学和分形理论，借助UTM-100万能试验材料机，开展长大纵坡沥青路面层间抗剪切及剪切疲劳理论与试验研究，项目紧密结合实际工程，解决沥青路面层间抗剪切疲劳性能衰减问题，为长大纵坡沥青路面材料选择和结构设计提供理论基础与技术支撑。取得主要成果如下：.（1）探明了动粘弹剪切参数随冻融循环的变化规律，确定了恢复率和不可恢复蠕变柔量随冻融循环的变化关系及两者之间关系，并建立了考虑动粘弹剪切参数的沥青混合料动态模量主曲线模型。.（2）提出了可靠的FTIR定量分析方法；给出了不同特征官能团含量变化对沥青粘结材料路用性能参数的影响排序，并建立了通过特征官能团含量来预测复数剪切弹性模量的预估方程。.（3）建立了沥青路面层间粘层材料与集料的抗剪强度理论模型；建立了沥青路面、层间粘层材料自身抗剪强度理论模型；建立了西北山区长大纵坡沥青路面层间联合抗剪强度理论模型。.（4）对改进的人工神经网络模型进行理论推导，借助MATLAB编制了沥青混合料试件抗剪强度BP神经网络预测代码，建立了沥青混合料试件层间抗剪切强度的预测模型。.（5）以不同剪应力水平下的剪切疲劳寿命预估方程为基础模型，对其进行频率、温度、冻融循环次数和实际应用参数修正，建立了考虑冻融循环的层间剪切疲劳寿命预估方程。.（6）提出了沥青路面层间非脱层、部分脱层接触模态界面和全脱层接触模态的抗剪切疲劳衰减与失效机制。.（7）提出了西北山区长大纵坡沥青面层层间抗剪切疲劳对策。