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Title: EVALUATING ASPHALTENE SETTLING TEST AND RELATING RESULTS TO PHYSICAL PROPERTIES OF PAVING ASPHALTS
Accession Number: 00367359
Record Type: Component
Availability: Find a library where document is available Abstract: The asphaltene settling test was designed to measure the compatibility of the components of an asphalt cement by measuring the settling rate of teh asphaltene for a mixture of asphalt in hexane. The results are reported as the length of time required for the asphaltenes to settle out of a solution of hexane. The main premise on which the settling test is based is that the asphaltenes with the longer settling times are better dispersed in the hexanemaltene phase and that longer settling times indicate that the mixtures have more compatible components. The purposes of this study were (a) to evaluate the settling test in terms of test repeatability and the effect of varying selected parameters of the procedure on test results, (b) to determine the settling time of a series of asphalt cement specimens in order to investigate potential relationships between settling time and asphalt characteristics, and (c) to evaluate the effectiveness of asphalt modifiers such as softening agents and antistripping agents. Based on the results, it is felt that additional work is required if the test is to have a practical value. Nevertheless, the findings indicate that (a) the test has a fair repeatability; the coefficients of variation of settling times for 262 asphalts ranged from 2.8 to 9.4 percent; (b) the settling time of asphalt is sensitive to the test temperature; (c) no well-defined relationship was found between settling time and specification-type asphalt characteristics (penetration, viscosity, specific gravity, flash point); (d) the major factor that affected test results was the asphalt producer; and (e) the addition of antistripping agents reduced the settling time with respect to the virgin asphalt, whereas the effect of adding a softening agent was inconsistent, although there was a tendency for reduced settling times. A modified procedure to simplify the procedure, to reduce the time and cost of performing the test, and to improve its repeatability is presented. (Author)
Supplemental Notes: Publication of this paper sponsored by Committee on Characteristics of Bituminous Materials. 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
Monograph Title: Monograph Accession #: 01411648
Authors: Roberts, Freddy LKennedy, Thomas WPagination: pp 111-118
Publication Date: 1982
Serial: ISBN: 0309033209
Media Type: Print
Features: Figures
(13)
; References
(4)
; Tables
(2)
TRT Terms: Uncontrolled Terms: Subject Areas: Highways; Materials; Pavements; I23: Properties of Road Surfaces
Files: TRIS, TRB
Created Date: Nov 30 1982 12:00AM
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