Mechanical Response Analysis Of Viscoelastic Layered System In Asphalt Pavement

Asphalt mixtures are typical viscoelastic materials. Realistic responses of asphalt pavements can only be obtained by conducting viscoelastic analysis. This study proposed a procedure for determining viscoelastic responses of multilayered asphalt pavements. A computer code is developed to determine the elastic responses of pavements subjected to uniform circular pressures according to the layered elastic theory. The results from the code were successfully, verified against those from BISAR and KENLAYER. Therefore, the intention of the study is to derive a viscoelastic solution able to take into account the time-and dependent-nature of the viscoelastic materials in the multilayered system. A linear viscoelastic solution for the multilayered system subjected to a cylindrical unit step load is derived from the elastic solution by using the principle of elastic-viscoelastic correspondence.The viscoelastic behavior of asphalt concrete is characterized using the Prony model. The relaxance of asphalt concrete is obtained by replacing the corresponding variables in the Prony model and is substituted into the elastic solution to obtain the step response function in the Laplace domain. The time domain response is solved through numerical Laplace inversion. The response due to an arbitrary loading history is solved using an incremental formulation of convolution integral taking advantage of the Prony series representation of step response function. The computer code developed for elastic analysis is extended to implement the viscoelastic analysis procedure and the results are in good agreement with those obtained from finite element analyses, the analysis based on the viscoelastic solution is much faster than finite element analyses. The procedure developed in this study provides an effective tool for pavement analysis and design.