Synthesis of Warm Mix Asphalt Paving Strategies for use in Montana Highway Construction

The objective of this research project is to synthesize the latest research on warm mix asphalt paving technologies and provide the Montana Department of Transportation with implementation recommendations.

Use of Warm Mix Asphalt (WMA) as an alternative to conventional Hot Mix Asphalt (HMA) is gaining national momentum. WMA uses recent technological advances that reduce the temperature needed to produce and compact asphalt for use on roadways. It offers the potential to reduce construction costs by lowering energy use, improving quality and efficiency of construction, and improving environmental stewardship through decreased air emissions. These benefits make WMA technologies appealing to highway agencies and the asphalt paving industry given increased energy costs, reduced highway construction and maintenance budgets, and tighter environmental regulations. Despite these promising benefits, numerous experimental studies and construction projects using WMA have demonstrated varying levels of performance. Several problems have been identified related to increased and premature rutting of surface asphalt concrete courses, moisture damage, and various types of pavement distress. MDT has expressed an interest in examining WMA technologies for use in Montana. Through this project, WTI researchers will examine recent national and international research in Europe to evaluate the applicability of WMA technologies for Montana roadway conditions, and to develop a set of implementation recommendations.