Comparison of Nonlinear Analysis Algorithms for Two Typical Asphalt Pavement Analysis Programs

Two representative programs, MICH-PAVE and KENLAYER, are selected and compared to many key aspects of their analysis algorithms to achieve an in-depth understanding of the features of the Finite Element Method and elastic layered system theory in nonlinear material analysis of the structure of asphalt pavement. Furthermore, by conducting a case study, the impact of using different analysis methods on the calculation results is presented. Moreover, the feasibility of the equivalent resilient modulus obtained by the Finite Element Method is discussed. The results show that the difference among the nonlinear analysis algorithms used by the two software packages is mainly reflected in the determination of the initial resilient modulus, the stress correction, and the convergence condition. Besides, the Finite Element Method could consider the variation of the resilient modulus induced by the change in the stress condition in both the radial and the depth directions simultaneously. In contrast, the theory of the elastic layered system only considers the dependence of the resilient modulus on the stress in the depth direction. Additionally, the use of diverse nonlinear analysis methods has different levels of impact on mechanical responses. Finally, the equivalent resilient modulus obtained by nonlinear analysis can be used to calculate mechanical responses of pavement structure except the surface deflection in a linear analysis.