01033519

Component

This paper describes how it is well documented that environmental effects play a significant role in modifying the material properties, which in turn affect the pavement performance. Studies under the Strategic Highway Research Program (SHRP) were carried out to study the oxidative age hardening characteristics of asphalt binders and mixes. As a result, laboratory procedures to simulate the field-hardening of asphalt binders and mixes were developed. These procedures were adopted by American Association of State Highway and Transportation Officials (AASHTO) as Provisional Protocols PP1-98 and PP2-99. A research study, National Cooperative Highway Research Program (NCHRP) 9-23, was initiated to verify these protocols, identify their limitations, and make recommendations to enhance their predictive capabilities. This paper is a part of the NCHRP 9-23, which deals with the PP2-99 Protocol. Binders and field cores were obtained from Long Term Pavement Performance (LTPP) and other sites across the United States. Plant-mix, laboratory-aged cores, and field-aged cores were characterized using complex modulus (E*) testing. Verification of the existing protocol was carried out using the data collected from testing. Warmer climates resulted in higher aging compared to cooler climates. Laboratory cores were found to have more uniform aging profiles than field cores. Hence, it was concluded that the existing protocol is insufficient to accurately predict the field aging of asphalt mixes. Based on the findings, recommendations were made for future research work and subsequent improvement of the protocol. The recommendations apply only for asphalt mixes containing conventional, non-modified binders.

01020180

06-1287

English

18p

2006

Transportation Research Board 85th Annual Meeting

CD-ROM

Figures (10) ; References (9) ; Tables (1)

Age hardening; Asphalt mixtures; Binders; Core samples; Data collection; Laboratory tests; Pavement performance; Properties of materials

Aged binder; Oxidative hardening

Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways

Transportation Research Board Annual Meeting 2006 Paper #06-1287

TRIS, TRB

Mar 3 2006 10:38AM