Highway asphalts vary in consistency from the water-thin liquids used in dust palliatives to solid asphalts pulverized into powder form and used for blending purposes. The various types include: Hard Asphalts, Asphalt Cement, Slow-Curing Liquid Asphalts (SC Road Oils), Rapid-Curing Liquid Asphalts (RC Cutbacks), Medium-Curing Liquid Asphalt (MC Cutbacks), and Asphalt Emulsions. Cutback asphalt is simply a combination of asphalt cement and petroleum solvent. Some are thin enough to be used as prime oil or tack, while others must be heated for use. Their uses included dust control, pavement maintenance, construction (chip seal) and cold mix patching.