The Construction and Performance of Ultra-thin Whitetopping Intersections on US-169

The Minnesota Department of Transportation (Mn/DOT) constructed an ultra-thin whitetopping (UTW) project at three intersections on US-169 at Elk River to gain more experience in both the design and performance of ultra-thin whitetopping. A brief description of the Mn/DOT’s history in the area of whitetopping is presented followed by a detailed description of the construction of the instrumented whitetopping test sections on US-169. All concrete mixes contained either polypropylene or polyolefin fibers. The compressive strength, flexural strength, Poisson’s ratio and elastic modulus were measured for these mixes and the results are provided. Distinct cracking patterns developed within each test section. The UTW test sections with a 1.2-m x 1.2-m (4-ft x 4-ft) joint pattern included corner breaks and transverse cracks. Corner breaks were the primary distress in the test section with a 1.8-m x 1.8-m (6-ft x 6-ft) joint pattern, although very little cracking was exhibited. The strain measurements emphasize the importance of the support provided by the HMA layer. A reduction in this support occurs when the temperature of the HMA is increased or when the HMA begins to ravel. Cores should be pulled from the pavement when evaluating whether UTW is a viable rehabilitation alternative to determine if the asphalt is stripping and if the asphalt layer has adequate thickness. UTW can be successfully placed on as little as 76 mm (3 in.) of asphalt, if the quality of the asphalt is good. The cores should also reveal the asphalt layer is of uniform thickness and stripping/raveling has not occurred. If these conditions exist, UTW is a good option for rehabilitating asphalt pavements.


  • English

Media Info

  • Media Type: Web
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; Tables;
  • Pagination: 183p

Subject/Index Terms

Filing Info

  • Accession Number: 01054633
  • Record Type: Publication
  • Report/Paper Numbers: State Project No. 7106-60
  • Created Date: Jul 30 2007 10:48AM