The simplified viscoelastic continuum damage model has been widely accepted as a tool to predict fatigue performance of asphalt concrete. One key component in the model is the damage characteristic curve that results from a cyclic fatigue test. This curve characterizes the relationship between material integrity (stiffness) and the level of damage in the material. As with any experimental measurement, it is important to know and quantify the variability of the damage curve, but traditional statistical methods are ill-suited for experiments that yield functional data as opposed to univariate data. In this study, a variance index of the damage characteristic curve is first proposed and compared with the expert judgment of the variance of a set of nine different asphalt mixtures. Then, an example analysis for establishing the repeatability limit of a specific mixture as the application of the variance index is presented using the resampling method and hypothesis test. The major findings are as follows: 1) the proposed variance index can match the expert judgment of variability; 2) the shape of the damage characteristic curve can affect the performance of the variance index; 3) the resampling method and hypothesis test can be applied to flag inconsistent data in multi-user or multi-laboratory results; and 4) the resampling method can also be used to construct the repeatability limit of the variance index.

简化的粘弹性连续体损伤模型已被广泛用作预测沥青混凝土疲劳性能的工具。该模型的一个关键组成部分是循环疲劳试验得出的损伤特征曲线。该曲线表征了材料完整性（刚度）与材料损坏程度之间的关系。与任何实验测量一样，了解和量化损伤曲线的可变性很重要，但是传统的统计方法不适用于产生功能数据而不是单变量数据的实验。在这项研究中，首先提出了损伤特征曲线的方差指数，并将其与一组9种不同沥青混合料方差的专家判断相比较。然后，通过重采样方法和假设检验，介绍了使用方差指数确定特定混合物的重复性极限的示例分析。主要发现如下：1）提出的方差指数可以与专家对变异性的判断相匹配；2）损伤特征曲线的形状会影响方差指标的表现；3）重采样方法和假设检验可用于标记多用户或多实验室结果中不一致的数据；4）重采样方法也可用于构建方差指数的可重复性极限。1）提出的方差指数可以匹配专家对变异性的判断；2）损伤特征曲线的形状会影响方差指标的表现；3）重采样方法和假设检验可用于在多用户或多实验室结果中标记不一致的数据；4）重采样方法也可用于构建方差指数的可重复性极限。1）提出的方差指数可以匹配专家对变异性的判断；2）损伤特征曲线的形状会影响方差指标的表现；3）重采样方法和假设检验可用于标记多用户或多实验室结果中不一致的数据；4）重采样方法也可用于构建方差指数的可重复性极限。