FHWA’s National WMA Overview
Jan 03, 2012
- By December 2011, 40 State DOTs and all Federal Lands Divisions will have a specification and/or contractual language that allows WMA on Federal-aid or Federal Lands projects.
- By December 2012, at least 30 State DOTs will have achieved set targets for WMA usage.
- Over 30 WMA technologies are offered.
- TRB completed NCHRP Report 691: “Mix Design Practices for Warm Mix Asphalt”. The National Highway Institute offers an on-demand web course, FHWA-NHI-131137, covering the material.
- Two NCHRP projects focus on WMA in 2012: NCHRP 9-52 “Short-Term Laboratory Conditioning of Asphalt Mixtures” and NCHRP 9-53 “Asphalt Foaming Characteristics for Warm Mix Asphalt Applications”.
- A study on “Recycled Asphalt Shingles (RAS) and Recycled Asphalt Pavement (RAP) in HMA/WMA Mixtures” is proposed for 2013.
- NAPA issued a 2nd Edition of Warm-Mix Asphalt: Best Practices
Looking ahead, the FHWA will work on implementation of standardized mixture design procedure (AASHTO R35 Appendix) and emphasize performance testing of WMA using Asphalt Mixture Performance Tester (AMPT) and lab conditioning of WMA mixtures for mechanical testing. Finally, long term performance in the field will continue to be a research focus.
Author: Heather Dolan