基于间接拉伸的老化沥青混合料残余寿命评价

为评价老化沥青混合料残余寿命，通过室内模拟老化条件制作试件和现场取芯试件，采用一次性间接拉伸试验探讨不同老化时间水平下试件的弹性模量、破坏模量以及劈裂强度演化规律，提出了以弹性模量为基础的老化系数评价指标；采用应力控制模式下的间接拉伸疲劳试验，研究了老化系数、残余疲劳寿命以及累计耗散能的关系。结果表明:在不同老化时间水平下，各评价指标的变化幅度存在显著差异，在老化初期弹性模量和破坏模量的变化幅度高于劈裂强度，弹性模量敏感性强、区分度高以及变异系数小能可靠和合理地评价老化沥青混合料力学性能；在短期老化时，老化系数增量显著，随着老化程度增加，老化系数增量趋于平稳；老化系数与残余疲劳寿命、累计耗散能存在良好的相关性，残余疲劳寿命和累计耗散能随着老化系数的增加而增加。

Evaluation of Residual Life of Aged Asphalt Mixture Based on Indirect Tensile

To evaluate the residual life of aged asphalt mixture, specimens were fabricated and cored in situ via simulating aging conditions indoor. The evolution laws of elastic modulus, failure modulus and splitting strength of specimens under different aging time levels were studied by one-time indirect tensile test, and the aging coefficient evaluation indexes based on elastic modulus were proposed. The relationship among aging coefficient, residual fatigue life and accumulative dissipated energy was studied with indirect tensile fatigue test under stress control mode. The result indicates that under different aging time levels, there are significant differences in the variation range of each evaluation index and at the beginning of aging, the variation range of elastic modulus and failure modulus is higher than that of splitting strength. That the elastic modulus has some advantages of high sensitivity, high differentiation and low coefficient of variation can be used to evaluate reliably and reasonably the mechanical properties of aged asphalt mixture. In the short-term aging, the increment of aging coefficient is significant, however, with the increase of aging degree, it tends to be stable. The aging coefficient has a good correlation with residual fatigue life and accumulative dissipated energy and the residual fatigue life and accumulative dissipated energy increase with the increasing of aging coefficient.