A Review of Warm Mix Asphalt
Arif Chowdhury and Joe W. Button, Texas A&M University, December 2008, 75 pp. (473700-00080-1)
Warm Mix Asphalt (WMA) technology, recently developed in Europe, is gaining strong interest in the US. By lowering the viscosity of asphalt binder and/or increasing the workability of mixture using minimal heat, WMA technology allows the mixing, transporting, and paving process at significantly lower temperature. Using this new technology, asphalt mix can be produced as much as 100ºF lower than traditional hot mix asphalt (HMA). Several benefits of lower mixing and compaction temperature include: less emission, savings in energy cost, longer construction season, less odor, and construction during non-peak periods. Despite the apparent benefits, some researchers are concerned about the long-term performance of this new mixture. In last few years, dozens of field test sections have been constructed thorough out the USA using different WMA technologies. It is too early to report the performance; but so far, no negative performance has been reported in the literature. In the last few years, several large national and state level research projects have been initiated to evaluate, validate, and implement this new technology.
This report documents the results of a comprehensive review of worldwide information dealing with the following issues as related to warm mix asphalt: Current state of the art/practice of WMA; cost and benefits of WMA technology; plant modifications to accommodate WMA; mixture design; durability and performance; performance related testing; quality control; specifications; and construction guidelines.
Keywords: Warm Mix Asphalt, Hot Mix Asphalt
ENTIRE REPORT (Adobe Acrobat File – 940 KB)