Volume 36, Issue 1 (January 2008)
Characterization of Louisiana Asphalt Mixtures Using Simple Performance Tests
The main objective of this study was to characterize the performance of HMA mixes based on four laboratory tests, including three simple performance tests (SPTs) dynamic modulus ∣E∗∣, flow time (Ft), flow number (FN), and a Loaded Wheel Tracking (LWT) test. In addition, two dynamic modulus prediction models, namely Witczak and Hirsch, were evaluated. Thirteen plant-produced HMA mixtures were selected in this study. Laboratory characterization tests included the dynamic modulus ∣E∗∣, flow number (FN), and Hamburg-Type LWT tests. Test results indicated that the ∣E∗∣ test was sensitive to the nominal maximum aggregate size (NMAS) in the HMA mixture. Larger aggregates combined with recycled asphalt (RAP) tended to have high ∣E∗∣ values at high temperatures. Both the Witczak and Hirsch models could predict the dynamic modulus ∣E∗∣ values with a reasonable reliability. However, the Witczak model reliability increases for higher NMAS. On the other hand, the Hirsch model reliability increases for lower NMAS. The general ranking of the SPTs and LWT test was similar. In addition, this ranking was consistent with the field use of those mixtures in terms of their design traffic volume.