Experimental CRCP Whitetopping Project on Interstate Highway 35 in Texas (05-0895)
Manuel Trevino, University of Texas, Austin
B. Frank McCullough, University of Texas, Austin

Whitetopping is a technique for resurfacing deteriorated asphalt pavements in which a relatively thin concrete pavement slab is placed on top of the old asphalt. It is a viable rehabilitation alternative to asphalt overlays for heavy-traffic roads. The Texas Department of Transportation implemented an experimental continuously reinforced concrete pavement (CRCP) whitetopping project to rehabilitate a 1-mile (1.61-km) segment on Interstate Highway 35 (IH-35), north of Laredo, Texas. The project goal was to find the best conditions for a whitetopping layer in the range of 7 to 9 in. (18 to 23 cm) thick that would provide satisfactory service over a 20 to 30-year design period, and that could be a prototype for the development of similar future projects in that region of Texas. This paper emphasizes the need for suitable conditions under which successful whitetopping projects can take place, such as good support from the substrate for the new concrete layer, water table at a depth greater than the capillary rise, and no stripping of the existing asphalt concrete pavement. These conditions were sought along the project segment to find an ideal site. During construction, three critical factors were closely monitored, namely, the use of a coarse aggregate with low thermal expansion for the concrete, the temperature of the concrete mix, and the prompt application of curing compound. Following construction, the section’s performance was monitored by means of condition surveys and deflection tests, which results revealed that the site selection and the monitoring of critical factors produced the desired outcome.