Evaluation of Portland Cement Concrete as a Rehabilitation Option for Overlaying an Existing Asphalt Roadway
Record Type: DOT

Whitetopping is the process of placing concrete on an existing asphalt roadway. An advantage of whitetopping is the ability to resist rutting and shoving that can cause collection of water on the roadway. Whitetopping impedes structural related distresses such as loss of support, pumping, faulting and corner breaks when constructed on a strong base. Another advantage of this process is to bridge isolated problems that would be reflected through a flexible pavement. The concept behind whitetopping is that when PCC is bonded to an underlying layer of asphalt, the two form a composite layer forcing the neutral axis in the slab downward. This would cause more of the concrete to be acting in compression rather than tension. Whitetopping has not been a rehabilitation method used by the North Dakota Department of Transportation in the past. The objective of this experimental feature is to determine if whitetopping is a feasible option for rehabilitation of an asphalt roadway. In order to determine the effectiveness of whitetopping as possible rehabilitation technique, the North Dakota Department of Transportation (NDDOT) elected to set up a test section to collect and evaluate performance data on this type of project. The NDDOT has constructed three test sections of 5", 6", and 7" of PCC to be placed over an existing asphalt section. Each whitetopping test section was approximately 500' in length. The project is located on US Highway 52 between Pingree and Buchanan, ND. The project will be evaluated on visual distresses and ride for a period of ten-years with reports every two-years. Test sections 1 and 3 are showing the most distresses. The primary distress is longitudinal cracking. Test sections 1 and 3 are adjacent to hot bituminous pavement sections. Test section 1 had a 40’ longitudinal crack that appeared immediately after construction. Test section 2 is performing well with only minor distresses. The control section is performing well with minor rutting and two transverse cracks. The longitudinal cracking in test sections 1 and 3 are likely the result of poor subgrade conditions. The location of the longitudinal cracks is in the same area as the distresses shown in photo 1 prior to whitetopping the asphalt. These distresses appeared to have reflected through the whitetopping sections. The ride remains good in all sections.
Start date: 1998/6/30
End date: 2008/6/30
Status: Active
Contract/Grant Number: ND 1998-01
Secondary Number: NH-2-052(012)244
Total Dollars: 0
Source Organization: North Dakota Department of Transportation
Date Added: 12/02/2004
Index Terms: Portland cement concrete, Overlays (Pavements), Asphalt, Whitetopping, Rutting, Pavement distress, Flexible pavements, Performance evaluations, Research projects, North Dakota,

Federal Highway Administration
http://www.fhwa.dot.gov/
1200 New Jersey Avenue, SE
Washington, DC 20590
USA
Phone: (202) 366-4000

Fuchs, Bryon
Phone: (701) 328-6903

North Dakota Department of Transportation
http://www.state.nd.us/dot/
300 Airport Road
Bismarck, ND 58505
USA
Phone: (701) 328-2500
Fax: (701) 328-1420

Fuchs, Bryon
Phone: (701) 328-6903