01373256

Component

Reflection cracking is a common occurrence when distressed asphalt concrete (AC) pavements are rehabilitated with a mill-and-inlay approach. Economic pressures often lead agencies to use this approach which facilitates the need for fatigue cracking resistant materials that can withstand a high strain environment and restore the structural integrity of the pavement. A newly formulated high polymer content mixture (HPM) was recently placed at the National Center for Asphalt Technology Pavement Test Track in a heavily distressed pavement section. In preparation for the inlay, approximately half the depth of the existing structure was milled and cracking was observed on portions of the milled surface. The inlay has performed extremely well with respect to rutting, cracking and ride quality. The focus of this investigation, however, was an examination of the structural response of the section before and after the HPM inlay. Extensive deflection testing and backcalculation quantified a statistically-significant increase in the AC modulus of 55% after the inlay. There was also a noted reduction in the modulus variability. As expected, given the increase in AC modulus, measured asphalt strain, aggregate base pressure and subgrade pressure were all reduced after the inlay at a reference temperature of 68F. A 29% reduction in asphalt strain, a 51% reduction in aggregate base pressure and a 21% reduction in subgrade pressure were all found to be statistically significant. Given these findings, the HPM material was found to have an immediate and significant impact on the measured pavement properties and responses critical to its performance.

01362476

12-1728

English

17p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; References; Tables

Asphalt concrete pavements; Asphalt mixtures; Backcalculation; Deflection tests; Pavement distress; Polymers; Reflection cracking; Rehabilitation

Mill-and-inlay treatments

Highways; Maintenance and Preservation; Pavements; I22: Design of Pavements, Railways and Guideways; I60: Maintenance

Transportation Research Board Annual Meeting 2012 Paper #12-1728

TRIS, TRB

Feb 8 2012 5:04PM