TRB Webinar: Special Mixture Design Considerations and Methods for Warm-Mix Asphalt

TRB conducted a web briefing or "webinar" on September 12, 2011, from 2:00 p.m. - 4:00 p.m. EDT that explored procedures for designing dense-graded, asphalt concrete mixtures that will be produced using currently available warm-mix asphalt (WMA) processes.

WMA refers to asphalt concrete mixtures that are produced at temperatures approximately 50°F (28°C) or more cooler than typically used in the production of hot-mix asphalt (HMA). WMA can provide similar strength, durability, and performance characteristics as HMA using substantially reduced production temperatures. Producing asphalt at reduced temperatures provides environmental and health benefits, such as lower greenhouse gas emissions, lower fuel consumption, and reduced exposure of workers to asphalt fumes.

The design of WMA requires some changes to current HMA mix design practices.  This webinar will explore procedures for designing dense-graded, asphalt concrete mixtures that will be produced using currently available WMA processes.  These WMA mix design procedures are based on research conducted in a National Cooperative Highway Research Program (NCHRP) project, Mix Design Practices for Warm Mix Asphalt, which concluded that only minor modification of current mix design practice is needed to address WMA.  To implement the modifications for WMA, researchers developed an appendix to the current dense-graded HMA mix design procedure, Standard Practice for Superpave Volumetric Design for Hot-Mix Asphalt (HMA).  This appendix, Special Mixture Design Considerations and Methods for Warm Mix Asphalt (WMA) is the subject of this webinar.

Presenters for this session:

• Ramon Bonaquist, Advanced Asphalt Technologies, LLC, will present an overview of the appendix, Special Mixture Design Considerations and Methods for Warm Mix Asphalt (WMA), and will provide background information about its development.  
• Brian Prowell, Advanced Materials Services, LLC, will present data from the NCHRP project in which the appendix was used to perform mix designs for several field projects.
• Rick Harvey, Wyoming Department of Transportation, will provide an update of efforts to incorporate the appendix into the AASHTO Standard Methods of Test.

Learning objectives:
Upon completion of the webinar, the audience will be able to identify the modifications of the current Superpave volumetric design procedure, AASHTO R-35, that are needed to design warm-mix asphalt mixtures.

The webinar recording is available.  There is no fee for employees of TRB sponsors who register using their work email address. In addition to employees of TRB sponsor organizations, the following are eligible to receive complimentary webinar registration:

•    TRB and National Academies employees;
•    Chairs of TRB Standing Committees, Sections, or Groups;
•    CRP panel members who were involved with developing the report or project that is the subject of the webinar;
•    Members of the media; and
•    Congressional staff members.

Others must pay $89 to obtain the recorded webinar. Contact Reggie Gillum at RGillum@nas.edu to receive the recording.