This dissertation is compiled of the findings of several phases of a detailed research study
that was aimed at investigating the Skid Resistance phenomenon.
In the first phase of the dissertation research a study was performed to evaluate the
different factors that influence frictional measurements obtained using the Dynamic
Friction Tester (DFT). A temperature calibration factor that would account for
temperature effects on DFT readings and IFI computations was developed. In addition,
other variables that also affect the friction measurements obtained using the DFT are
identified.
In the next phase of the dissertation research the effect of pavement roughness on the
Skid Resistance was investigated. The variation of the normal load and its nonlinear
relation to SN was used to explain lower SN values measured on relatively rougher
surfaces. The feasibility of using the International Roughness Index (IRI) and the
Dynamic Load Coefficient (DLC) as predictors of the reduction in SN due to pavement
roughness was also investigated.
In the final phase of the dissertation research an in-depth investigation was carried out to
better understand the principles underlying the concept of the International Friction Index
(IFI), and specifically the role played by the Speed Constant (
Sp) parameter in the IFI
computations. The parameter
Sp dictates the speed variation of the wet friction
measurements taken on a given pavement surface. The results of the current investigation
suggest the revision of the procedure for computation of the
Sp parameter to incorporate
device specific properties.
Furthermore, the incorporation of vehicle characteristics in the
Sp parameter
computations would help address a well known deficiency of the IFI, which is the
inconsistent
FR60 (predicted friction at 60 km/h) obtained from the friction values
measured at two different slip speeds on the same surface. This study also showed that
the modification of the
Sp parameter reduces significantly the slip speed dependency of
the device calibration parameters
A and B.
Finally, a modified IFI procedure that incorporates device specific slip conditions is
presented. The modified IFI procedure showed consistently better predictive capability
than the conventional ASTM procedure on all the different devices considered in this
study.
| Identifer | oai:union.ndltd.org:USF/oai:scholarcommons.usf.edu:etd-5116 |
| Date | 06 November 2009 |
| Creators | Fuentes, Luis G. |
| Publisher | Scholar Commons |
| Source Sets | University of South Flordia |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Graduate Theses and Dissertations |
| Rights | default |
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