Asphalt is a material commonly used in PAVING roads and other surfaces. It is made up of a combination of PITCH, BITUMEN, TAR, and BLACKTOP. PITCH is a sticky, black, viscous liquid or semi-solid form of petroleum. BITUMEN is a black, highly viscous liquid or semi-solid form of petroleum. TAR is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. BLACKTOP is a type of asphalt pavement. Repaving is the process of laying new asphalt over an existing surface. PAVING is the process of laying down a surface, such as asphalt, for a road or other area.