Full-Scale Pavement Testing of a High Polymer Modified Asphalt Concrete Mixture

Abstract

Asphalt concrete (AC) mixtures with high polymer (HP) content (i.e., >6% polymer content) may offer additional advantages in flexible pavements subjected to heavy and slow-moving traffic loads. The objective of this effort was to evaluate the structural response of an HP AC mixture using full-scale pavement testing. Two experiments were conducted: Experiment 1 consisted of a PMA AC layer on top of a crushed aggregate base (CAB) and a subgrade (SG), and Experiment 2 consisted of an HP AC layer with a reduced thickness on top of the same CAB and SG. Both pavements were subjected to dynamic loads applied at the pavement surface simulating falling weight deflectometer (FWD) loading conditions. Pavement surface deflections along with critical pavement responses at different depths and locations within the pavement layers were monitored during testing through embedded instrumentations. Field-produced mixtures were sampled during construction and evaluated for performance properties. At the end of each experiment, cores were cut from the AC layer for in-place density measurements. In general, at the centerline of the load, the reduced thickness of the HP AC layer resulted in higher vertical surface deflections and vertical stresses at the middle of the CAB layer and at 15.2 cm below the surface of the SG layer. The mechanistic analysis of the built pavement structures showed that the HP pavement would result in better AC fatigue and rutting performance, higher rutting in the unbound layers, but similar total pavement rutting.