01373817

Component

In this study, a new approach was used to evaluate changes in asphalt concrete microstructure under full-scale accelerated pavement test loading with a Heavy Vehicle Simulator (HVS) of composite pavement. The approach compared X-ray computed tomography (CT) images taken before and after HVS rut testing. Results were used to identify the differences in the movement of aggregate and changes in air-void content and distribution occurring during rutting accumulation of rubberized gap graded and polymer modified dense graded mixes for two overlay thicknesses (64 and 114 mm). Although high air void content for the sections constructed with rubberized gap graded mix were expected to cause more densification related rutting and earlier failure related to this densification, the actual reason behind the earlier failure was determined to be primarily greater shear flow to the sides of the wheelpath associated with the gap gradation and small aggregate size. Significant movement of aggregate was observed in the direction of travel as well as to the side under the pushed wheel. Important differences in aggregate movement and air-void changes were also observed between different overlay thicknesses indicating the depth of the rut phenomenon, important information for the design of overlays on aged asphalt concrete as well.

This paper was sponsored by TRB committee AFD40 Full-Scale Accelerated Pavement Testing

01362476

12-4300

English

22p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; References; Tables

Air voids; Asphalt concrete pavements; Heavy vehicles; Load tests; Microstructure; Ruts (Pavements); Tomography

Heavy vehicle simulators; X-ray computed tomography

Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I33: Other Materials used in Pavement Layers

Transportation Research Board Annual Meeting 2012 Paper #12-4300

TRIS, TRB

Feb 8 2012 5:23PM