Permeability of Coarse Matrix-High Binder Mixtures and Its Effects on Performance
Author(s):
R.P. Izzo, J.W. Button
Publication Date:
April 1997
Abstract:
The primary objective of this study is to evaluate permeability of coarse matrix-high binder (CMHB) mixtures in comparison with dense-graded mixtures and estimate the relative effects on pavement performance. Specific objectives include (1) developing a permeability test protocol, (2) comparing oxidative aging of CMHB and dense-graded mixtures, (3) comparing moisture susceptibility of CMHB and dense-graded mixtures, (4) monitoring field performance of CMHB field test pavements, and (5) suggesting methods to optimize performance of CMHB mixtures.The primary objective of this study is to evaluate permeability of coarse matrix-high binder (CMHB) mixtures in comparison with dense-graded mixtures and estimate the relative effects on pavement performance. Specific objectives include (1) developing a permeability test protocol, (2) comparing oxidative aging of CMHB and dense-graded mixtures, (3) comparing moisture susceptibility of CMHB and dense-graded mixtures, (4) monitoring field performance of CMHB field test pavements, and (5) suggesting methods to optimize performance of CMHB mixtures.Findings indicate CMHB mixtures are more permeable than dense-graded mixtures at similar air void contents; however, these differences are generally small and often statistically insignificant. Permeability of newly constructed CMHB pavements is often quite high, but usually decreases rapidly with traffic to acceptable levels. Flushing was the most common form of early CMHB pavement distress. However, this was usually explained by excessive asphalt above the optimum. Because of the coarse texture, even with some flushing the texture appeared comparatively good. TxDOT static creep testing did not conclusively establish that CMHB mixtures are less rut-susceptible than corresponding dense-graded mixtures. CMHB mixtures are generally more resistant to moisture damage and oxidative aging than dense-graded mixtures made using similar materials.
Report Number:
1238-1F
Electronic Link(s):
Document/Product
http://tti.tamu.edu/documents/1238-1F.pdf
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