Performance of Sustainable Materials, Construction Practices Highlight Fourth Track Cycle
NCAT hosted the fourth Pavement Test Track Conference in February, highlighting how the test track helps turn theory into practice and enables transportation agencies to do more with less. Along with presentations from NCAT researchers, the conference also featured representatives from sponsoring agencies who discussed how longer-lasting, safer, more economical roads are the direct result of implementing test track research.
The fourth research cycle began in 2009, when 17 of the track’s 200-foot test sections were either reconstructed or rehabilitated. The remaining 29 sections were left in place to allow for additional traffic loading. Trafficking began in August 2009 and ended in September 2011 after 10 million equivalent single axle loads (ESALs) were applied. “The timing of fleet operations was scheduled so that the 25-month testing cycle included three summers,” says Dr. Buzz Powell, NCAT’s assistant director and manager of the Pavement Test Track.
Warm-Mix and RAP: A Winning Combination
Using warm-mix asphalt (WMA) technologies in recycled asphalt pavement (RAP) mixes is a win-win scenario in every respect. The cost benefits are evident—reduced material costs and less fuel usage. Plus, the enhanced workability of warm-mix can facilitate using increased RAP contents, which translates into even greater cost savings.
Visiting Scholars Get Useful Research, Unique Auburn Experience
When Flavio Padula graciously describes his experience as an NCAT visiting scholar as “perfect,” he is referring to both his work at NCAT and his family’s quality of life in Auburn.
“Besides all the great opportunities that I was given at NCAT, coming to the U.S. was also a wonderful event for me and my family,” Padula said. “We really enjoyed Auburn and American people.”
NCAT invites your comments and questions, which may be submitted to Karen Hunley at email@example.com.
Greg Sholar, Florida DOT: What lift thickness is optimal for SP-4.75 mixtures? What thickness would be considered too thin for good paving practices? Is there a maximum thickness where rutting becomes an issue? What binder grade is being used in this mix type?
Former NCAT Associate Director Receives AAPT Honor
Prithvi (Ken) Kandhal, associate director emeritus of NCAT, recently received honorary membership in the Association of Asphalt Paving Technologists (AAPT). This honor comes after 40 years of work in the AAPT and the field of asphalt pavement design and construction.
Lab Testing Materials with the Vacuum Oven
Testing asphalt pavement materials such as aggregate, reclaimed asphalt pavement (RAP) and mixture specimens often requires that samples be dried to a constant mass. Most labs accomplish this using convection ovens or fan drying, depending on sample type. The National Center for Asphalt Technology (NCAT) recently completed a study to determine if vacuum ovens are an economically feasible alternative to convection ovens and fan drying in an asphalt pavement lab.
A new specification requirement has been issued related to segregation in dense-graded mixtures. For visually identified segregated areas, cores will be obtained and measured for in-place density. Areas having a density less than 90.0 percent Gmm will have to be removed and replaced.