Method of preparing superhydrophobic asphalt

A method of forming a superhydrophobic asphalt, the method comprising:

• applying a layer of polypropylene granules to a surface of a polymer modified asphalt,
• wherein the polymer modified asphalt has a softening point of 80 to 95° C., a viscosity at 135° C. of 1575 to 1650 cP, a ductility at 25° C. of 11.5 to 17.5 cm, a flash point of 300 to 360° C., and a performance grade of 76-10,
• wherein the polypropylene granules are substantially free of fluoropolymers, have a maximum particle size of 250 μm, a minimum particle size of 100 μm, and are present on the uncured coated asphalt in an amount of 185 to 275 g polypropylene granules per m2 of surface of the polymer modified asphalt,
• to form an uncured coated asphalt;
• and
• curing the uncured coated asphalt
• at 75 to 150° C. and at a temperature less than the melting point of said polypropylene granules, for 15 to 90 minutes,
• to form the superhydrophobic asphalt, wherein:
• the superhydrophobic asphalt comprises a polypropylene layer disposed upon a polymer modified asphalt layer, has a water contact angle of 145 to 170°;
• and
• wherein the polypropylene layer is present in an amount of 50 to 125 g per m2 of polymer modified asphalt layer, has a Ra surface roughness of 10 to 50 μm, and the polypropylene particles are mostly attached to the asphalt surface perpendicularly, as opposed to sideways, and
• wherein the superhydrophobic asphalt has a work of adhesion of 1 to 15 mN/m.