NCAT Test Track Sponsor Meeting
May 17, 2011
Mike O'Leary and I traveled to Auburn, AL to attend the NCAT Test Track Sponsor Meeting on Wednesday, May 11, 2011. The purpose of this meeting was to get an update of how the test sections are performing as they approach the end of the fourth research cycle.
To summarize for those who are not familiar with the test track:
- It is a 1.7 mile loop comprised of 46, 200 ft, sections that are sponsored on 3 year cycles.
- Five heavily loaded tractor-trailers circle the track 16 hours a day, five days a week.
- The trucks apply 5 to 6 times the damage of legally loaded trucks.
- The pavement accumulates 10 million ESALs during the research cycle (typical damage seen after 20 years on a rural interstate highway accelerated into 2-3 years).
- Performance data is continuously monitored (rutting, cracking, roughness, etc)
In 2009, eight WMA sections were constructed. Buzz Powell stated that all of the WMA sections had slightly higher rutting than the HMA (6-7 mm compared to 5 mm) but that each technology was comparable in terms of surface performance. The Evotherm section had the lowest mix temperature of 250 F. That’s 25°F less than all of the other WMA sections at 275°F and 85°F less than the HMA Control!
Wednesday afternoon, we walked around the track and examined each section. There was no visual difference between S9 (HMA), S10 (Foam), and S11 (Evotherm). All sections looked to be performing the same. The next reconstruction will occur during the Spring/Summer of 2012.
I also wanted to note that part of the original Evotherm section (E10) that was placed in 2005 remains on the track and is still performing well after 18 million ESALs!
Author: Jenna Michael