A Comparison and Evaluation of Probabilistic Models of Arrangement of Linear and Nonlinear Elastic Behavior of Material in Asphalt Pavement Layers with Mechanistic-Empirical Method

So far, there has not been a fixed behavioral model capable of fully describing the complex behavior of materials such as aggregates in all conditions. Because of economic considerations, asphalt pavements layers are usually made of different materials and thicknesses. This study, 6 pavement models were designed, aiming to examine the effects of different material behavior on the lifespan of asphalt pavements, using KENLAYER software. These models were: 1.linear elastic sub-base and subgrade and nonlinear elastic base; 2.linear subgrade and base and nonlinear sub-base; 3.linear base and sub-base and nonlinear subgrade; 4.nonlinear sub-base and base and linear subgrade; 5.nonlinear subgrade and sub-base and linear base; 6.nonlinear base and subgrade and linear sub-base. In all models, the behavior of Asphalt layer was viscoelastic. In order to benefit from economic conditions in implementation, each model was examined with fine-grained/granular material and with different layer thickness. The best models with lifespan of 12 to 25 years were models 3, 5, 6 with 18, 19, 24, 29 years respectively; the worst were models 1, 2, 4, 6 in fine-grained mode with a lifespan of 5, 6, 7 years. Based on the type of material behavior and layer thickness, the factor destructive to pavements varied between two damage rates, with horizontal tensile strain criterion bottom the asphalt layer and vertical compressive strain top the subgrade. With changes in the layer, thickness the models different results. Increasing the thickness of sub-base and decreasing the thickness of the base layer in model 1 and 2 increased the lifespan 3 and 11 years respectively, which can improve the plan in terms of cost. However, in models 3, 5, 6 it showed both increase and decrease in the lifespan; it had no tangible effects on model 4.