Potholes, birdbaths, cracks, ruts and loose gravel are nuisances and often hazards for users of many asphalt parking lots. By "whitetopping" a deteriorated "blacktop" pavement, the owner can make the lot do what it should--provide clean, safe and convenient parking for customers and employees. Whitetopping is the application of a concrete overlay of suitable thickness (usually 3, 3 1/2 or 4 inches) to increase the load-carrying capacity of the pavement and provide a clean, safe surface. Such an overlay will give many years of maintenance-free service.


The deteriorated asphalt parking lot at Mr. "C" Discount Liquors in Indianapolis was resurfaced with a thin concrete overlay in June 1984. The Metropolitan Indianapolis Ready Mixed Concrete Association (MIRMCA) presented the project as a whitetopping demonstration.

Preparing the base--For the most part, the only subbase preparation necessary on this project was sweeping with a stiff broom to remove all loose material. On jobs that have large potholes in the blacktop, some leveling should also be done to prevent large variations in the concrete slab thickness.

Setting forms--Because the pavement was specified 3 1/2 inches thick, wood 2x4s were convenient side forms. The 2x4s were nailed to short wood studs, and the studs were spiked to the blacktop.

Placing concrete--The overlay was placed in alternate lanes using a manually pulled vibrating screed. Slump was specified not greater than 3 inches. Control joints were formed in the fresh concrete with a tool that could cut a groove 1/4 the thickness of the overlay.