Forensic investigation of the cause(s) of slippery ultra-thin bonded wearing course of an asphalt pavement: influence of aggregate mineralogical compositions |
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| Authors: | Mengesha A Beyene Richard C Meininger Nelson H Gibson Jose F Munoz Jack Youtcheff |
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| Affiliation: | 1. SES Group and Associate, LLC, 614 Biddle Street, Chesapeake City, MD 21915, USA;2. Turner-Fairbank Highway Research Centre, Federal Highway Administration, 6300 Georgetown Pike, McLean, VA 22101, USA |
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| Abstract: | The cause(s) of slippery ultra-thin bonded wearing course (UTBWC) of an asphalt pavement was investigated. Petrographic analysis showed that the aggregate used in the UTBWC is mainly limestone with an average acid-insoluble residue of 5.1%. Coefficient of friction tests were performed both on a comparative UTBWC from Virginia with a different aggregate mineralogy VA-UTBWC and on slabs extracted from the slippery UTBWC pavement overlay. The tests clearly showed that the slippery UTBWC overlay sharply declined throughout the polishing process, consistent with the aggregate mineralogical composition and its low amount of acid-insoluble residue. In contrast, the comparative VA-UTBWC mix showed a gradual increase and then decrease in friction with continued polishing. This investigation clearly showed that the cause of the slippery asphalt pavement problem of the road mainly attributed to limestone aggregate polishing. |
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| Keywords: | polishing slippery ultra-thin bonded wearing course (UTBWC) skid resistance acid-insoluble residue coefficient of friction test |
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