Ultra-thin whitetopping--a concrete overlay less than 4 inches thick--is steadily growing in popularity as a solution to deteriorated asphalt pavements. One of the most recent projects involved the whitetopping of a highway intersection in Lancaster, Pa. Although the project is small (only 400 square yards), it is significant, since it marks the first use of ultra-thin whitetopping (UTW) by the Pennsylvania Department of Transportation (PennDOT). As is the case with most UTW applications, no bonding agents or cement slurries were used to bond the overlay to the milled asphalt base. However, the base was dampened just prior to concrete placement to prevent absorption of the mix water into the milled asphalt. To minimize traffic disruption, the UTW was a fast-track placement, with the concrete designed to reach a minimum compressive strength of 3000 psi in 24 hours.