To reduce time caused by road rehabilitation, highway engineers are giving more attention to whitetopping - placing an unbonded concrete overlay over deteriorated asphalt - as an alternative to reconstructing roads or resurfacing them with asphalt. The Colorado Department of Highways (CDOH) is evaluating whitetopping as a possible solution to the state's road rehabilitation problems. On June 2, 1990, it participated in a test project involving the whitetopping of a section of Harmony Road in Fort Collins. Concrete overlay sections of 3.5 inches thick and 5 inches thick were placed. For the next few years, the CDOH will monitor the performance of the two overlays.
Fast-track paving methods were used to demonstrate how quickly whitetopped pavements can be opened to traffic. Only 24 hours after paving began, the whitetopped sections were ready for service. The key to the success of fast-track overlay placement is to keep a constant supply of concrete in front of the paver to ensure continuous paving. Before opening the overlay to traffic, workers sawcut longitudinal and transverse joints. Instead of waiting for concrete to set before sawing the joints, they used a special lightweight saw to cut joints only two hours after overlay placement.