Concrete Overlays or Whitetopping: Pavement Repair

Whitetopping is a portland cement concrete overlay on existing asphalt concrete pavement. It can be used as a road surface course where traditional paving materials have failed due to rutting or general deterioration.

There are three types of whitetopping:

  • Conventional (thickness greater than 8 inches)
  • Thin (thicknesses over 4 but less than 8 inches.)
  • Ultra-thin – (2 to 4 inches) Ultra-thin whitetopping (UTW) is a bonded, fiber reinforced concrete overlay.

This rehabilitation option has been used for many years on airport pavements, highways, secondary roads, and other pavements.

Whitetopping offers:

  • Improved performance — no rutting or washboarding
  • Ability to maintain surface grade – many installers mill off the amount of asphalt that will be replaced by the UTW so that they don’t change the surface grade
  • Competitive price with other resurfacing methods

Whitetopping contributes to sustainable solutions by:

Cool. Concrete’s higher albedo reduces heat islands.  If part of a project site may contribute to LEED Credit SS 7.

Minimizes waste. Less material to landfill – most of the existing, worn asphalt pavement serves as a base for the concrete, thus eliminating the need and expense to tear up and haul away the asphalt

Base. Most of the existing, worn asphalt pavement is left in place and serves as a base. Ruts in the asphalt are milled down to start with a clean level surface. Ultra-thin whitetopping (UTW) should not be placed over asphalt pavement that shows signs of deep pavement distress. If potholes, alligator cracking, or deep fissures exist in the asphalt, the concrete will not form an adequate bond, resulting in pavement that lacks adequate support. Asphalt pavement should be at least 3-inches thick to provide a sufficient base for UTW. Many installers mill off the amount that will be replaced by the UTW so that they don’t change the surface grade. Whitetopping can be placed using conventional paving equipment.

Joints. Joint spacing is critical to a good performing UTW project. Successful projects use a short joint spacing to form, in effect, a mini-block paver system. Experience indicates that joint spacings should be no more than 12 to 18 inches each way per inch of whitetopping thickness. For example, a 3-inch UTW surface should be jointed into 3x 3 or 4×4 foot squares. Joints are sawed early to control surface cracking.