Unified Mechanistic Approach for Modeling Tests of Unbound Pavement Materials

Abstract

Several tests are used for the characterization of unbound materials for pavement applications. The resilient modulus has been one of the most common tests for design specification of unbound materials. The California bearing ratio (CBR) is another laboratory test that is frequently used. The dynamic cone penetrometer (DCP) test is a more common test for in situ quality assessment/quality control of unbound materials. For better connection between design and quality assurance (QA)/quality control (QC), it would be helpful to have a reliable, mechanistic method for correlating test results. This is particularly true for the use of new materials, for which there is not an extensive body of data to empirically draw such connections. This paper presents a framework for a unified approach for modeling these tests. A discrete-element method (DEM) is used to simulate the CBR test, the DCP test, and the resilient modulus test. An initial evaluation demonstrated that the simulations can account for the effect of aggregate shape, size, gradation, friction, and stiffness. As such, this methodology shows promise for the development of mechanistic-based correlation between test results. These results are presented, along with some limitations of the current model and challenges for the future.