Investigation of Proposed AASHTO Rut Test Procedure Using the Asphalt Pavement Analyzer

About the report:

The Virginia Department of Transportation uses the Asphalt Pavement Analyzer with beam specimens to test and approve asphalt mixtures for rut resistance. Some agencies use cylindrical specimens that impart distinct testing advantages such as the ease of fabrication. This study attempted to develop a correlation between measurements using beams and cylindrical specimens. A secondary purpose was to locate and test mixes that had rutted in the field so that the precise laboratory criteria that define rutting could be determined. The tentative AASHTO procedure using cylindrical specimens with 4 percent air voids provided poor correlations with the conventional beam test results. A second testing using 8 percent air voids provided a better correlation, but the testing of cylindrical specimens was more variable than the testing of beam specimens. Therefore, the researchers recommended that VDOT continue testing beam specimens for approval and research. Correlations were developed that will allow the automated system of rut measurement to be used for future testing. VDOT pavements were found to develop negligible rutting, so the attempt to identify failed sections and ultimately failure criteria were not successful.

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