Modeling cyclic behavior of unbound aggregates using two-surface plasticity theory

Abstract

Various empirical rutting models have been proposed to predict the permanent deformation of aggregate base/ subbase layers in pavements. Nevertheless, an analytical model is required for large-scale finite element simu-lation of the pavement structure. A two-surface plasticity theory is used to predict the long-term cyclic behavior and provide path-dependent material responses of aggregates. The deviatoric stresses for each aggregate were determined based on the shear stress ratio and the shear strength properties at source and engineering grada-tions. The proposed rutting model was optimized and validated via repeated load triaxial tests using 11 aggre-gates. The numerical results demonstrate that the proposed model accurately describes aggregates with low-level permanent strain and thus enables the yield surface, long-term shear strain, and path-dependent resilient modulus to be assessed. Overall, the proposed physics-based modeling approach can help understand and predict the deformation behavior of aggregates subjected to moving-wheel loads.