ABSTRACT

Currently, Egypt is using the [AASHTO, 1993 AASHTO, 1993. Guide for design of pavement structure. Washington, DC: American Association of State Highway and Transportation Officials. [Google Scholar]. Guide for design of pavement structures. Washington, DC: American Association of State Highway and Transportation Officials] guide for the flexible pavement structural design. In this method the resilient modulus (M_R) of the unbound granular base/subbase materials and subgrade soils is a measure of material stiffness used for characterisation. It is considered one of the major factors affecting the pavement layerthicknesses. However, in Egypt, California Bearing Ratio (CBR) is the main strength parameter used for characterisation of the unbound materials and subgrade soils due to its availability and simplicity. In this research, a comprehensive experimental testing programme was conducted on different unbound granular base/subbase materials typically used in pavement construction projects in Egypt. The testing programme includes M_R, CBR, and basic material properties. The effect of aggregate gradation on M_R is investigated. A model predicting M_R as a function of the basic material properties is proposed. The M_R–CBR relationship adopted in the current Egyptian Code of Practice is verified based on the testing results. The experimental data warranted the calibration of the current model. The calibrated model has reasonable goodness of fit statistics and yields rational M_R estimates for the local materials.

摘要

目前，埃及正在使用 [AASHTO, 1993AASHTO，1993 年。路面结构设计指南。华盛顿, 直流:美国国家公路和运输官员协会。 [谷歌学术]。路面结构设计指南。华盛顿特区：美国国家公路和运输官员协会] 柔性路面结构设计指南。在这种方法中，弹性模量 (M_R) 未结合的粒状基层/底基层材料和路基土壤是用于表征的材料刚度的量度。它被认为是影响路面层厚的主要因素之一。然而，在埃及，加州承载比 (CBR) 是用于表征未结合材料和路基土壤的主要强度参数，因为它的可用性和简单性。在这项研究中，对埃及路面建设项目中通常使用的不同未粘合颗粒基层/底基层材料进行了全面的实验测试计划。测试程序包括 M _R、 CBR 和基本材料特性。研究了骨料级配对 M _R的影响。预测 M _R的模型建议作为基本材料特性的函数。现行埃及行为守则采用的MR-CBR关系是根据测试结果验证的_。实验数据保证了当前模型的校准。校准后的模型具有合理的拟合优度统计数据，并为当地材料产生合理的 M _{R估计值。}