Iowa Ultra Thin Whitetopping at Two Years of Age, HR-559, 1996

(1996) Iowa Ultra Thin Whitetopping at Two Years of Age, HR-559, 1996. Transportation, Department of


File Size:994kB


An 11.6 km research project was constructed in 1994 on a portion of Iowa Highway 21 in Iowa County, from U.S. 6 to Iowa Highway 212. This research is intended to evaluate the effect of four primary variables on long term performances of the PCC concrete overlay, commonly called whitetopping. The variables are thickness (50 mm, 100 mm, 150 mm, and 200 mm), joint spacing (0.6 m squares, 1.2 m squares, 1.8 m squares, and 4.6 m spacing), fiber use (concrete with and without polypropolene fibers) and surface preparation (patch only, scarifying the surface, and cold-in-place recycling). After two years, only two sections exhibit a small amount of debonding and distress cracking. Both sections are 50 mm thick. Within each of these two sections, only 2% of the area is affected. Two other 50 mm thick sections have a small number of cracks but no debonding has been found. No adverse effects of these cracks are evident. Three asphalt overlay sections were also constructed. In each asphalt section, transverse cracks have recently been found. At two years of age, the research sections are performing very well. An insignificant number of cracks and no distressed areas have been found in any research sections thicker than 50 mm.

Item Type: Departmental Report
Keywords: Debonding, Fiber reinforced concrete, Overlays (Pavements), Whitetopping, Ultra thin whitetopping
Subjects: Transportation > Pavements
Transportation > Pavements > Concrete
Transportation > Research
Transportation > Design and Construction
Transportation > Maintenance and preservation
ID Code: 17096
Deposited By: Iowa DOT Library
Deposited On: 06 Jun 2014 17:47
Last Modified: 15 Jan 2015 15:21