Ultra-Thin, Fiber-Reinforced Concrete Overlays for Urban Intersections

Abstract

An industry partnership involving state and local highway officials; ready mix concrete producers; and fiber, admixture, and cement suppliers paved the way for extensive testing of a new concrete technology in Tennessee. Known as ultra-thin whitetopping (UTW), this experimental repair procedure involves placing a layer 50 to 75 mm (2 to 3 in.) thick of high-strength concrete over milled asphalt. Crucial to a long life for the thin concrete is a high synthetic fiber content, normally 1.4 kg/m3 (3 lbs/yd3) with joints spaced at a minimum of 0.92 to 1.22 m (3 to 4 ft) on center. From 1992 to 1995, seven cities in Tennessee participated in UTW demonstrations. The field tests were so successful that synthetic fiber-reinforced UTW is now being bid on many state and local projects. Presently, the primary use of UTW is to rehabilitate high average daily traffic intersections. Other potential uses include overlays of residential streets, parking lots, and airport aprons.