Back-Calculation of Resilient Modulus of Lightly Stabilized Granular Base Materials from Cyclic Load Testing Facility

Resilient moduli of pavement layers are the basic input parameters for the design of pavements with multilayers in the current mechanistic-empirical pavement design guides. Field measurements are generally believed to provide accurate values to backcalculate pavement layer moduli, but the tests to measure the relevant parameters are difficult to perform, expensive and causes disturbance to the public. Therefore, backcalculation of pavement layer moduli from laboratory scale model testing has been a focus of recent pavement research. This paper presents a backcalculation analysis to evaluate pavement layer moduli using a 3D numerical model developed using the FLAC3D finite difference software. The pertinent measurements that are required for the backcalculation analysis were collected from a cyclic load testing facility under traffic type cyclic loading conditions with a typical pavement structure consisting of a granular road base lightly stabilised with cement-flyash over an expansive soft clay subgrade. This study indicates that the stabilised base material had cross-anisotropic resilient properties with an average vertical resilient modulus of 2875 MPa and an average horizontal resilient modulus of 1598 MPa. From this investigation, the resilient moduli of the stabilized granular base layer and subgrade clay were backcalculated reliably from the analysis using FLAC3D numerical model.