Techniques for Assessing the Nonlinear Resilient Response of Unbound Granular-Layered Structures
The resilient stress-deformation characteristics of aggregates that form granular pavement layers are reviewed. A standardized plate bearing test (PBT) is proposed that separates resilient and permanent deformation readings and detects material stress dependency. A nonlinear, stress-dependent model proposed by Ehrler is used to reproduce the observed deformation behavior of a granular layer subjected to repeated plate bearing tests at different applied stress levels. The use of equipment exploiting the relationship between resilient behavior and the natural frequency of vibration of a mass resting on a semi-infinite half space (the natural vibration method—NVM) is described. The results predict granular pavement stiffnesses when a nonlinear, stress-dependent model is employed, and these are very simply related to PBT results obtained on the same material. The NVM approach may be more practical than the modified PBT procedure proposed as it can be used more quickly.