The Asphalt Pavement Analyzer (APA) device was used to characterize the impact of
various mix factors on the development of permanent deformation in dense-graded
mixes given a standard compactive effort. Factors included two aggregate sizes, three
VMA levels, two fines contents, three binder contents and four binder types. All
specimens received the same compactive effort (100 gyrations) using the Superpave
Gyratory Compactor (SGC). For some tests, testing temperatures followed the
standard APA test protocol (64C) and for some others, the test temperature was set at
the high temperature of standard performance asphalt binder grade (e.g. 70C for a PG
70-22 asphalt binder).
Statistical results showed that increased binder content increased permanent
deformation in the 19.0 mm dense graded mixes prepared with the PG 64-22 binder
irrespective of the other mix parameters. These effects were not noted in the mixes
prepared with PG 70-22 and PG 76-22 binders, when tested at 64C. However, the
same effect was noted when mixes prepared with PG 70-22, PG 70-22 Modified and
PG 76-22 binders were tested at the high temperature of standard performance asphalt
binder grade. All mixes prepared with the stiffer binders showed very low permanent
deformation when tested at the standard 64C regardless of the value of the other mix
parameters. The statistical analysis of permanent deformation provides evidence that
the mixes prepared with the PG 76-22 and PG 70-22 Modified binders perform better
than mixes prepared with the PG 70-22 and the PG 64-22 binders. The effect of VMA
on permanent deformation depends on the maximum aggregate size used, test
temperature, binder type and the fines content. It was not possible to separate these
interaction effects. The results of this study suggest that the APA is relatively
insensitive to changes in mix properties within the range of variables studied, when
using the standard APA test temperature (64C). However, the APA device is sensitive
when the test temperature matches the high temperature of the standard performance
binder grade (e.g. 70C for a PG 70-22 binder).
Based on the results of this study, it appears that the APA can be used to indicate the
rut resistance of a mixture. Although some of the mix factors have an interactive effect
in the mixes, the APA has a potential to predict the relative rutting of the hot mix
asphalt mixes even when polymer modified mixes are used, provided that testing is
conducted at the appropriate test temperature. / Graduation date: 2005
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29432 |
| Date | 16 November 2004 |
| Creators | Sandoval-Gil, Jesus A. |
| Contributors | Lundy, James R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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