Asphalt mixture compositely modified by ethylene-vinyl acetate copolymer, naphthenic oil and polyphosphoric acid and preparation method thereof

The invention provides an asphalt mixture compositely modified by an ethylene-vinyl acetate copolymer, naphthenic oil and polyphosphoric acid and a preparation method of the asphalt mixture, and aims to solve the technical problems of improving high and low temperature diseases and aging resistance of an asphalt pavement while ensuring the pavement performance of the asphalt mixture. The composite modified asphalt mixture is prepared from the following raw materials in parts by weight: 100 parts of mineral aggregate, 5 to 7 parts of asphalt, 0.24 to 0.49 part of ethylene-vinyl acetate copolymer, 0.1 to 0.21 part of naphthenic oil and 0.025 to 0.105 part of polyphosphoric acid. The composite modified asphalt mixture provided by the invention belongs to an environment-friendly, non-toxic and non-corrosive composite asphalt mixture, is excellent in pavement performance, can enhance the high-temperature stability, low-temperature crack resistance and water stability of an asphalt pavement, has great significance