A Minnesota, USA transportation research blog titled “CROSSROADS” reported that in June, MnROAD—the only cold-weather accelerated pavement testing facility of its kind in North America—will begin construction on its third phase of research since 1994, the initial time MnDOT rebuilt in partnership with other states.
Dozens of new experiments are planned along MnROAD’s test tracks in rural Albertville: the high-volume original Interstate-94 westbound (built in 1973), the mainline I-94 westbound (originally opened in 1994) and an adjacent low-volume road closed track.
National Road Research Alliance (NRRA)—recently formed by six states and numerous industry partners—will co-sponsor the reconstruction. NRRA-prioritized research will support state and local needs. Dave Van Deusen, MnDOT Research Operations Engineer, said,
“The advantage of having these test sections at MnROAD is that we can take bigger risks and push the envelope in terms of mix designs and layer thicknesses for both asphalt and concrete layers that could not be done on a public roadway.”
Forensic analysis of failed cells
Each test section that is being reconstructed will receive a final forensic study before any reconstruction starts and the old test cells are dug up—allowing researchers a look at each layer to see the distress that has occurred over the years—and make the final analysis of why it failed. There are always many theories on the causes of what actually leads to failure, but until the forensic is performed, there isn’t attestation as to what happened. These findings will help build longer-lasting pavements in the future. Plans were made available for contractors on March 31, 2017; April 28 is the bid letting; and construction begins June 5 and continues until November 2017.
Focus Areas
- HMA overlay and rehab of concrete and methods of enhancing compaction—New mix designs were developed to promote long-term performance, including how reflective cracking effects can be minimized through design or other joint treatment.
- Cold central plant recycling—How can these layers best be used and what type of surface mix or chip seal can be placed on top?
- Fiber-reinforced concrete pavements—Nationally, states want to get a better understanding of the beneficial use of fibers in concrete pavement layers.
- Long-term effects of diamond grinding—Questions arise as to whether diamond grinding might accelerate deterioration in each state’s reactive-aggregates pavements.
- Early opening strength to traffic—What effect does heavy traffic loading have on the long-term performance of full-depth concrete pavement, as well as fast–setting repairs?
- Optimizing the mix components for contractors—What effect do low-cementitious content mixes have on long-term performance and constructability of concrete pavements?
- Compacted concrete pavement for local streets—a form of roller compacted concrete (RCC) that has a standard concrete pavement surface texture. The RCC industry has been successful in Michigan and Kansas constructing CCP pavement on local streets. This research will determine if the texture that is accomplished is durable in harsh freeze-thaw climates.
- Recycled aggregates in aggregate base and larger sub-base materials—States continue to look for effective ways to recycle materials into unbound bases.
- Maintaining poor pavements—Road owners continually have less funding to maintain their roadway systems…
- Partial-depth repair of concrete pavements—Agencies continually seek improved materials and methods for the repair of concrete pavements.
- Thin overlays—Experimenting with very thin overlays can provide a real benefit for many roads currently out there—with thin overlays, the ride can be smoother and the life of older roads can be extended.
To read the entire “CROSSROADS” research blog, please go to: https://mntransportationresearch.org/tag/fibe-reinforced-concrete/.
home page: MnROAD has two 3.5 mile test segments on Interstate 94
and one closed 2.5-mile low-volume road.