Since being rediscovered in the late 1970s, whitetopping has become a standard method for rehabilitating deteriorated asphalt pavements. Adding a thin (usually 3 to 4 inches) concrete overlay greatly increases load-carrying capacity. The new surface is also free of nuisances found in many asphalt pavements: potholes, birdbaths, soft spots, ruts, and loose material.
Have whitetopped pavements placed during the past several years lived up to these claims? To answer that question we've collected performance data and photographs from parking lot overlays up to 8 years old. The data come from several states, all in cold climates.
Does whitetopping really reduce parking lot maintenance costs? Parking lot owners we talked with say yes, without a doubt. In most cases they've spent nothing to keep the lot performing well. The keys to good performance were: closely spaced joints, usually 10 feet apart or less; air-entrained 4000-psi concrete; and timely curing.