Integrating Traditional Characterization Techniques in Mechanistic Pavement Design Approaches

Abstract

Although widely applicable and useful, the traditional CBR test does not provide the mechanical behaviors such as resilient and permanent deformation characteristics of granular road materials. A relatively simple testing technique is developed to characterize the resilient modulus of granular materials based on the traditional CBR test using repeated load cycles. The Finite Element Method (FEM) analysis has been attempted for the purpose of modeling the Repeated Load CBR and derives an equivalent resilient modulus of the sample as a bulk. Strain gauges were used to measure the lateral deformation of the CBR mould from which the confining stress can be estimated to determine a stress dependent resilient modulus. Furthermore, a large scale cyclic load triaxial test was carried out to validate the result of the repeated load CBR on coarse granular materials from South Africa and Ethiopia. The repeated load CBR test is quite useful to estimate the resilient modulus of unbound granular materials that can be used as an input in mechanistic pavement design analysis in the absence of triaxial testing facilities.