Layered Viscoelastic Analysis with Moving Loads of Low-Volume Roadway Pavement Response

Abstract

Low-volume roads (LVRs) are typically not expected to withstand large amounts of traffic, consequently they have relatively thin pavement structures. However situations can occur when traffic loading rapidly increases, resulting in rapid structural deterioration of the pavement. Examples include resource exploration and production, new industrial facilities, and military operations. Improved evaluation procedures, including computation of pavement structural responses, are needed to accommodate these scenarios. This paper reports recent advances in methods for computing the structural response of LVRs that incorporate viscoelastic asphalt material behavior and accommodate moving loads. Application of layered elastic analysis, using a Hankel transform with numerical integration methods, is popular in several mechanistic-empirical pavement design procedures. This paper describes an application of the collocation method for approximating the creep compliance and viscoelastic solution, which removes the necessity for approximating the Laplace transform inversion. This was coupled with Boltzmann’s superposition principle for moving loads. Comparisons showed that the proposed approximate method matched well with the viscoelastic solution, and with the full-scale instrumented test data of highway pavements. The measured near surface response of a thin LVR test pavement subjected to military truck loads was then modeled to determine the suitability of the approach for LVR. The modeled results for asphalt strain and vertical pressure in the granular layers showed generally good agreement with the measured instrumentation data. The developed structural response model provided a more realistic simulation of flexible pavement viscoelastic material behavior and accommodation of moving loads with similar computational speed to a conventional layered elastic approach.