The use of warm mix asphalt (WMA) technology offers significant benefits, notably, lower energy demand during production and construction, reduced emissions at the plant and the paver, and increased allowable haul distances. However, it also presents potential engineering challenges. Lower WMA production temperatures and the water injection used with some WMA technologies have raised concerns about possible rutting and moisture susceptibility of WMA pavements. Thus, facilitating the implementation of WMA technologies in the United States requires the collection and analysis of definitive information on the material and engineering properties and long-term performance of WMA pavements constructed with the wide range of WMA technologies now available.
The objectives of this research were to (1) compare the long-term performance of WMA and HMA pavements and (2) identify material and engineering properties of WMA pavements that are significant determinants of their long-term field performance.
The project final report is available as NCHRP Research Report 843.
Databases containing detailed information on the field projects evaluated during NCHRP Project 9-49A and related material test results are available here for download: New Projects and Existing Projects. A database of input data for the Pavement ME Design analyses discussed in the project final report is available on request to NCHRP.