Cass County Hwy. 11 Thin Concrete Overlay – Mapleton

Looking for opportunities to re-establish a concrete paving program on county highways, the Cass County Highway Department were able to budget additional funds for this project to construct one of the first thin concrete overlays in North Dakota. In spite of some of the most unsupportive soil types in North Dakota, concrete pavements have performed admirably in Cass County. Based on experiences in other states, this project will also provide a long service life, even with the 5” concrete thickness.

Engineers at an early stage recognized that design effort for this project was little different than that for asphalt overlays. The preparation of life cycle cost (LCC) analysis comparing this 5” concrete overlay to thinner asphalt overlays with less expected service life showed the opportunity for significant upside. Other upside opportunities not included in the LCC were minimizing impacts of load limits for this heavily traveled truck route, safety aspects of the concrete pavement and long life with little maintenance. Even when the project reaches the end of its service life, the pavement can easily be milled out and recycled, as no steel was used. Based on these upside opportunities, the Cass County Board of Commissioners gave approval.

From the beginning, the Contractor gave the project its highest priority. Knowing the traffic would be severely limited during construction, the Contractor committed to constructing the job over a couple week period during a lull in agricultural work during June. The Contractor asked the ready mix producer for maximum effort to make practical progress in slip form paving work. Using 23 trucks at times transporting mix, paving progress was rapid, with one mile paving per day possible. To maximize access to concrete, much of the paving work was performed at night. Concrete paving work was finished in 11 days, with additional time required for asphalt shoulders.

Communication and partnership in effort was a key to success in getting the road open in the earliest possible time. Use of ready mix was a key element to success so the Contractor’s batch plants could remain productive on other projects. Final ride smoothness was excellent due to dedication to the use of slip form paving technology and superior crew efforts.