00636327

Component

http://onlinepubs.trb.org...trr/1993/1391/1391-001.pdf

https://scholar.google.co...sley&publication_year=1993

Oxidative aging of asphalt is a primary cause of asphalt hardening in pavements, thus contributing to various forms of pavement cracking. Although the changes in asphalt physical properties on oxidative aging are primarily the result of the formation of oxygen-containing functional groups in the asphalt, the sensitivity of an asphalt to these oxidation products varies widely with asphalt source (composition). An understanding of the kinetics of oxidation in the pavement temperature range is confounded by both the complex composition of asphalt and its thermally reversible microstructure. To better understand the mechanisms of age hardening, the kinetics of asphalt oxidation were investigated from the pavement temperature range [60 deg C (140 deg F)] through the higher temperature range of commonly used accelerated laboratory tests [130 deg C (266 deg F)]. It was found that asphalts with different component compatibilities may exhibit similar age hardening kinetics at the low end of the pavement temperature range, but quite different kinetics at the high end of the range. This is because the aging kinetics become highly dependent on how temperature affects the molecular microstructure. A new microstructural model of the age hardening of asphalt cement is presented that proposes that the kinetics of aging in the pavement temperature range is largely governed by physicochemical factors related to the state of dispersion of the molecular microstructure rather than the inherent reactivity of the molecular components with oxygen. The model is supported by results of past and present research.

This paper appears in Transportation Research Record No. 1391, Asphalt Cement and Asphalt/Polymer Blends. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01403229

English

p. 1-10

1993

Transportation Research Record

0309054621

Figures (13) ; References (11)

Accelerated tests; Age hardening; Asphalt; Asphalt hardening; Kinetics; Materials selection; Microstructure; Oxidation; Physicochemical properties; Temperature; Thermal stresses

Highways; Materials; I31: Bituminous Binders and Materials

TRIS, TRB, ATRI

Sep 14 1993 12:00AM

• COMPARING FIELD AND LABORATORY AGING OF BITUMENS ON A KINETIC BASIS
• EVALUATION AND DEVELOPMENT OF A PRESSURE AGING VESSEL FOR ASPHALT CEMENT
• NEW APPARATUS AND PROCEDURE FOR THE EXTRACTION AND RECOVERY OF ASPHALT BINDER FROM PAVEMENT MIXTURES
• PREPARATION AND CHARACTERIZATION OF ASPHALT-MODIFIED POLYETHYLENE BLENDS
• SOME ASPECTS OF THE EFFECT OF ASPHALT CHEMICAL COMPOSITION ON MATERIAL BEHAVIOR AND PAVEMENT PERFORMANCE