Microstructural effects on dynamic response of rigid and flexible pavements to moving load under plane strain

Abstract

Granular soils and asphalt concrete materials are characterized by microstructural effects due to their micro-stiffness and micro-inertia. In this work, an attempt is made to investigate if the material microstructure in rigid and flexible pavements affects their dynamic response to loads moving with constant speed under conditions of plane strain and linearity. The rigid pavement is modeled by a homogeneous isotropic and linearly elastic with viscous damping flexural plate resting on a homogeneous isotropic microstructured linear elastic with hysteretic damping half-pane. The flexible pavement is modeled by a layered half-plane with linear isotropic microstructured layers. The top (asphalt concrete) layer is viscoelastic, while the other layers are elastic with hysteretic damping. The dynamic response of both of the above rigid and flexible pavement models to a distributed over a finite length moving load is obtained by using the complex Fourier series approach in conjunction with compatibility and equilibrium at the plate/soil (for rigid pavements) and soil layers (for flexible pavements) interfaces. The so obtained analytical/numerical response solutions for rigid and flexible pavement problems, after verification, are employed for conducting parametric studies in order to assess the microstructural effects on the response of those pavements to moving loads. It was found, at least for the pavement cases considered here, that the presence of the stiff plate in rigid pavements and the viscoelastic top layer in flexible pavements reduce considerably microstructural effects on the pavement response, rendering them not so important for usual vehicle speeds. However, for vehicle speeds very close to the critical speed, microstructural effects become very important.