The primary use (70%) of aslt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create aslt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs. The terms "aslt" and "bitumen" are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, "aslt" (or "aslt cement") is commonly used for a refined residue from the distillation process of selected crude oils. Outside the United States, the product is often called "bitumen".