00663106

Monograph

http://onlinepubs.trb.org...nepubs/shrp/SHRP-A-369.pdf

The research results in this report concern the characterization of physical properties of asphalt binders and the development of test procedures for aging and adhesion. Asphalt binders were shown to be linear viscoelastic materials at expected pavement strains. Test methods and models describing rheological behavior were developed with the assumption of linear behavior. A mathematical model that contains parameters that can be used to relate physical and chemical parameters was developed. The test methods and models allow the stiffness of asphalt binders to be characterized as a function of loading time and temperature with the dynamic shear rheometer at intermediate to upper pavement surface temperatures and with a newly developed bending beam rheometer at low temperatures, where thermal cracking is important. To characterize fracture properties, the project developed a direct tension test, in which failure strain, stress, and energy are determined as functions of loading time and temperature. Limited work on fatigue properties at low temperatures successfully related them to tensile properties. A new phenomenon, low-temperature physical hardening, was identified during the project. This phenomenon results in increased stiffness of the binder when it is held at a constant temperature at room temperature or below. The blister test for quantitative measurement of adhesion between asphalt binder and aggregate surfaces was found to be impractical. The investigation of various factors, including film thickness, aging temperature, the effect of oxygen versus air, and the effect of mineral surfaces, led to a new aging procedure for simulating in-service oxidative hardening of asphalt binders, which was adopted as part of the new Strategic Highway Research program (SHRP) binder specification.

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

SHRP-A-369

English

475 p.

1994-4

0309057671

Figures; References; Tables

Adhesion; Asphalt; Asphalt cement; Binders; Concrete hardening; Equipment; Hardness; Physical properties; Research reports; Rheology; Shear modulus; Tension tests

Strategic Highway Research Program

Direct tension tests

Highways; Materials; I31: Bituminous Binders and Materials

TRIS, TRB, ATRI

Jul 19 1994 12:00AM