粒料回弹模量室内试验方法

回弹模量是表征粒料刚度和抵抗变形能力的一个重要指标.中国的《公路沥青路面设计规范》(JTG D50-2017)和美国路面力学-经验设计方法(MEPDG)均采用回弹模量作为沥青路面柔性基层的力学设计参数,用于表征基层材料在车辆动荷载作用下的刚度以及抗永久变形能力.首先,基于中外文献调研分析,介绍了粒料回弹模量的影响因素.其次,对中外回弹模量室内试验规程进行了对比分析,并结合室内粒料回弹模量试验结果,提出了粒料回弹模量室内试验方法中的不足和改进方案.最后,总结了中外现有常用回弹模量预测模型的主要考虑因素.研究成果有助于未来修订粒料室内回弹模量试验规程以及建立新的粒料回弹模量预测模型.

Laboratory Testing Methods for Determining the Resilient Modulus of Unbound Granular Materials

Resilient modulus (Mr) is an index for characterizing the stiffness and resistance to deformation of unbound granular materials (UGM). Both the Chinese 2017 Specifications for Design of Highway Asphalt Pavement and American Mechanics-Empirical Pavement Design Guide (MEPDG) Method use the resilient modulus as the only mechanical input parameter for structure design of pavement base layers, which can characterize the stiffness or resistance to permanent deformation of the pavement base layers under traffic loads. The present study was conducted to compare various laboratory Mr testing standards of UGM. First, factors that can significantly influence the Mr of UGM are discussed based on a comprehensive literature review. Second, the domestic and foreign laboratory testing standards for determining the Mr of UGM were compared. In addition, laboratory testing results were analyzed to reveal shortcomings of the testing methods, and corresponding methods for improving the shortcomings were proposed accordingly. Last, factors considered in the prediction models of the resilient modulus of UGM were summarized. Key findings presented in this paper can provide guidance for revising the laboratory testing standards and establishing new prediction models of resilient modulus of UGM.