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 fixed behavioral model capable of fully describing the complex behavior of materials such as aggregates in all conditions. Because of economic considerations, 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 pavements, using KENLAYER. These models were: 1.linear elastic subbase and subgrade; 2.linear subgrade and base; 3.linear base and subbase; 4.nonlinear subbase and base; 5.nonlinear subgrade and sub-base and linear base; 6.nonlinear base and subgrade . the behavior of Asphalt layer was viscoelastic. In order to benefit from economic conditions in implementation, examined with fine-grained/granular material and different layer thickness. best 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 ( finegrained ) with a lifespan 5, 6, 7. Based on type of material behavior and layer thickness, 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 layer, thickness models different results. Increasing the thickness of subbase and decreasing the thickness of base layer in model 1 and 2 increased the lifespan 3 and 11 years respectively, which can improve plan in terms of cost. However, in models 3, 5, 6 it showed both increase and decrease in lifespan; it had no tangible effects on 4.