GRAND FORKS -- In response to the many questions that have been asked of the North Dakota Department of Transportation, I would like to explain the process of road repair that was done on Demers Avenue, Gateway Drive and Interstate 29 in the Grand Forks area over the summer.
The concrete pavements on Demers Avenue and Gateway Drive were built many years ago -- Demers Avenue in 1972 and Gateway Drive in 1986-87. Concrete pavements are sawn into panels to control cracking, and over the years these panels have shifted, or faulted, which causes a bump at every sawn joint.
The faulted joints cause the thump, thump, thump we feel and hear on older concrete pavements.
Modern concrete pavements are built with dowel bars to help prevent faulting. And using dowel bars also gives us a way to bring old roadways up to date.
To repair the bumps, a newer type of technology called Dowel Bar Retrofit was the solution rather than complete reconstruction of the roadway. The Dowel Bar Retrofit technique involves cutting slots in the concrete and placing six steel dowel bars at the joint, much like a woodworker would glue in a wooden dowel to connect two pieces of wood.
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The slots then are filled with a quick-setting concrete grout.
Often, as was the case with Demers Avenue, Gateway Drive, and I-29, bad areas of concrete are removed and replaced prior to the Dowel Bar Retrofit project using a process called Concrete
Pavement Repair.
After the concrete repair and dowel bar work is completed, a pavement grinder is used to produce a smooth ride on the roadway.
Because sound concrete is long-lasting (30-plus years), repairs made to an existing concrete roadway can extend the life of the roadway many years at a fraction -- about one-tenth -- of the cost of new construction.
To reconstruct Gateway Drive would have cost about $20 million, while performing the concrete repair, dowel bar retrofit and grinding cost under $2 million. Another benefit is that although these projects disrupted traffic for a short time, the impact was far less than a complete reconstruction project.
Herald readers may feel free to contact me with their concerns or questions regarding our state highways. I can be reached by phone at (701) 787-6500, email at lnoehre@nd.gov or mail at PO Box 13077, Grand Forks, ND 58208-3077.
Noehre is Grand Forks district engineer for the North Dakota Department of Transportation.
