沥青混合料疲劳响应模型试验研究

首先总结分析了沥青混合料不同疲劳试验方法的特点、两种疲劳试验控制模式的适用范围,建议采用应力控制模式的间接拉伸疲劳试验方法。然后分析了不同试验因素的影响,选定了加载波型,确定了疲劳试验的应力比水平、频率及温度等试验参数的范围。采用旋转压实成型方法,对3种沥青混合料进行试件成型。分别考虑3种空隙率水平,应用均匀试验设计方法,进行了不同温度、频率、应力比水平下的间接拉伸疲劳试验,对试验结果进行了显著性分析,并应用多元线性回归方法,得到了适用于不同荷载条件下基于温度、频率、沥青饱和度、初始应变及初始劲度模量的沥青混合料疲劳模型。与国外疲劳模型进行了对比分析,表明得到的疲劳模型具有较好的比对性,可用于沥青混合料疲劳寿命的预估。

Researching on Fatigue Model of Asphalt Mixtures

Firstly different fatigue testing methods of HMA are summarized,the scope of applicability of two kinds of control mode are analyzed,and it is recommended that indirect tensile fatigue test with stress control mode be used.Then the effect of different testing factors are analyzed,the scope of the loading wave,stress ratio,frequency and temperature are selected.Three kinds of HMA specimens are compacted by gyratory compactor.Indirect tensile fatigue tests are carried out by uniform test design method under different temperature,frequency and loading,including asphalt mixes of three different voids ratio.Significance of the testing results is analyzed.The fatigue models are brought forward through multiple linear regression methods based on VFA,temperature,frequency,initial strain and initial modulus for general and heavy-duty loading.Comparative study is made of the fatigue models at home and abroad,it is shown that the fatigue models are comparable.They could be used for the fatigue prediction of asphalt mixtures.