重复荷载作用下沥青混合料流变次数试验

Experiment on Flow Number of Asphalt Mixture under Repeated Load

提出基于标准化应变率准则、粗糙惩罚法和霍尔模型的沥青混合料流变次数计算方法,通过重复荷载永久变形试验对3种沥青混合料的流变次数及变异性进行了研究,对其主要影响因素进行了敏感性分析,并以流变次数为主要控制指标建立了沥青混合料永久变形回归公式。研究表明基于标准化应变率准则的流变次数计算方法可以明显地减小计算离散性,计算结果更符合其真实物理意义。温度、荷载水平、围压水平以及加载时间等因素对流变次数均有显著影响。流变次数与斜率b以及不同荷载作用次数下的累积永久变形均有很好的相关性,可以作为沥青混合料抗车辙性能的评价指标。基于流变次数的永久变形回归公式可以在不同的荷载和环境条件下全程预估不同种类沥青混合料永久变形的发展过程。

A calculation method for flow number of asphalt mixture based on normalized strain rate criterion, roughness penalty method and Hoerl model is proposed. The repeated load permanent deformation test is conducted on three types of asphalt mixture to analyze their flow numbers and variability. The main factors of them are also investigated. Using the flow number as the main indicator, the regression formula of permanent deformation is derived for asphalt mixtures. It is found that （1） the proposed method can greatly reduce the calculation discreteness, the result can well match its physical meaning; （2） temperature, load magnitude, confining pressure magnitude and loading time have significant effects on flow number; （3） flow number has a good correlation with slope b and accumulative permanent deformation under different loading cycles, it can be used as an evaluation indicator to anti-rutting performance for asphalt mixtures. The regression formula of permanent deformation based on flow number can accurately predict the development of permanent deformation of different types of asphalt mixture under different loadings and environmental conditions.