Asphalt modifier for asphalt mixture and asphalt mixture containing the same

An asphalt modifier for an asphalt mixture, the asphalt modifier being intended to be mixed with an aggregate and an asphalt binder, the asphalt modifier comprising:

• a reinforcing fiber bundle of 1 to 10 wt % based on a total weight of the asphalt modifier, the reinforcing fiber bundle having a length of 8 to 34 mm and composed of a plurality of reinforcing fiber strands, wherein the reinforcing fiber bundle is a glass fiber bundle having 300 to 4,800 TEX (kg/km);
• and
• a coating layer comprising low-density polyethylene of 55 to 90 wt %, linear low-density polyethylene of 0.05 to 30 wt %, an inorganic material of 0.05 to 5 wt %, based on the total weight of the asphalt modifier, respectively, and at least one selected from the group consisting of an antioxidant and a UV stabilizer, the coating layer forming an envelope of the reinforcing fiber bundle, the low-density polyethylene and the linear low-density polyethylene having a melting point of 90 to 130° C.,
• wherein the inorganic material includes at least one selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, zeolite, talc, kaolin, zinc oxide, titanium dioxide, titanium oxide, alumina, aluminum hydroxide, magnesium hydroxide, glass fiber scrap, diatomaceous earth, and clay.