| Description |
Between 2007 and 2008, the Utah Department of Transportation (UDOT) has been collecting field material and testing it using the Asphalt Mixture Performance Tester (AMPT). Thirty-four field mixtures were evaluated as part of this study. The mixtures were produced following UDOT standard volumetric specifications and two binder grades, PG 64-34 and PG 70-28, from three suppliers. Based on the evaluation of the results obtained from these tests, it was found that the AMPT produced data with a coefficient of variation below 15%, indicating good repeatability. Mixtures prepared with different binder grades were easily separated. The dynamic modulus master curves of mixtures prepared using the same binder grade were essentially the same regardless of the aggregate source (same type of mixture was used). Given these results, it was shown that it is possible to obtain asphalt mixture level 1 MEPDG input parameters based on historic data, knowledge of the binder grade used and testing at only 1 temperature. The single temperature test can be used for quality control and to verify that the mixture is of the same kind as the historical data available. This approach can significantly reduce the time and effort required to obtain AMPT data without any loss in performance prediction capacity, thus making adoption of this device more appealing to state DOT's. |
