Notes from Asphalt in Depth
Jun 07, 2011
Several members of the MWV Asphalt Innovations team attended NAPA’s Asphalt in Depth seminar last week. You may have spoken with Mike O’Leary at the Evotherm booth or met Courtney Rice and Jenna Michael in one of the sessions. Several speakers discussed Warm Mix Asphalt: Matt Corrigan, FHWA, gave a national overview, Bob Frank of Compliance Monitoring Services addressed best practices; Brad Bradford, R.K. Hall Construction, shared his experience, and Mike Law, Scotty’s Contracting and Stone, dispensed some lessons learned.
Matt Corrigan spoke about the different NCHRP projects going on, including the NCHRP Report 691 ‘Mix Design for WMA’ coming from the 9-43 project. He said that based on this report people will need to simulate foaming in the lab. If a lab does not have a foamer, they may have to use foamed plant mix for the design. He also said that there is still a need to look at other performance criteria or possible design methods for aging because they have noticed that field results look good but lab tests do not in TSR, Hamburg, E*, and Flow. There needs to be more work done to see how WMA is aging compared to HMA in the field.
R.K. Hall has 12 plants and 5 of those have foamers. They produce around 275 F with temperatures of 250 F behind the screed. Fuel usage of the plants running warm mix averages a 19% savings compared to the ones running HMA. Using Evotherm, they produced around 270 F and lab densities were still higher than the target.
Mike Law with Scotty’s Contracting and Stone serves south central Kentucky. They have used Foam, Evotherm 3G, and Sasobit for research performed by Jonathan Fisher at the Kentucky Transportation Center. The Evotherm performed well at lay down temps around 230 and had similar densities to HMA.
There were lots of good questions during the panel discussion. Watch the Evotherm twitter feed this week for them and read the full list and summary on Behind the Screed next week.
Author: Jenna Michael