Towards and Integrated Pavement Design Approach: Using HWTD to Support the MEPDG
Sergey Grebenschikov and Jorge A. Prozzi, University of Texas at Austin, November 2010, 80 pp. (167274-1)
Variability of hot-mix asphalt (HMA) production can have drastic effects on pavement performance. A poor gradation or an inappropriate amount of asphalt binder could lead to early distresses and shorter pavement life. Other factors, such as the air void content in the asphalt layer, the type of aggregate gradation used in the mix or volumetrics, in general, can also have significant effects on performance.
This research study focuses on analyzing two techniques for observing the variability of mix production and its effects on pavement performance. First, this study focuses on using the Mechanistic-Empirical Pavement Design Guide (MEPDG) to analyze and predict the effect of the variability of HMA production on rutting in the asphalt layer. Then, this study makes an attempt to compare the results produced by the MEPDG with the results produced by the Hamburg Wheel Tracking Device (HWTD). In order to effectively establish correlations between the two techniques, an experiment was conducted during this research. This experiment focused on using volumetric data from a previous research project. The data from this project was used to model asphalt mixes and pavement structures in the MEPDG and the performance results were then compared to actual data obtained in the laboratory from the Hamburg Wheel Tracking Device (HWTD).
The variability of mix production was captured by analyzing three types of limestone mixes: a coarse dense-graded hot-mix asphalt (Type C, according to TxDOT specification), a fine dense-graded hot-mix asphalt (Type D), and a medium graded stone matrix asphalt (SMA-D). The master gradation band for each mixture was split into three categories: fine, target (actual job mix formula), and coarse. Each mixture was tested at a variable range of binder contents which were obtained using the TxDOT Mix Design Method (TxDOT, 2009). The variability of these mixes and their resistance to rutting as predicted by the MEPDG and measured by the HWTD is discussed in this report.
Keywords: Hot-Mix Asphalt, Asphalt Mix Production, Mechanistic-Empirical Pavement Design Guide (MEPDG), Hamburg Wheel Tracking Device (HWTD)
ENTIRE REPORT (Adobe Acrobat File – 967 KB)