The most common driveway surfaces are BLACKTOP, ASPHALT, TAR, GRAVEL, and PAVING. BLACKTOP is a mixture of ASPHALT and stone that is heated and poured into place. ASPHALT is a combination of bitumen and aggregate that is heated and applied to the surface. TAR is a petroleum-based product that is heated and applied to the surface. GRAVEL is a loose material made up of small stones and rocks that is spread over the surface. PAVING is a process of laying down a layer of concrete or ASPHALT over the surface. All of these materials provide a durable and attractive surface for driveways.