Multi-dimensional composite modified asphalt mixture and preparation method thereof

The invention provides a multi-dimensional composite modified asphalt mixture and a preparation method thereof, and aims to solve the technical problems that the pavement performance of an existing asphalt mixture is poor, and an asphalt pavement prepared from the asphalt mixture is difficult to be poor in high and low temperature performance and is seriously damaged by water. The composite modified asphalt mixture is prepared from the following raw materials in parts by weight: 80 to 120 parts of mineral aggregate, 5 to 6 parts of asphalt, 0.03 to 0.07 part of nano organic bentonite, 0.0005 to 0.0015 part of acorn, 0.004 to 0.008 part of graphene oxide and 0.10 to 0.14 part of polyurethane. The composite modified asphalt mixture provided by the invention belongs to an environment-friendly, non-toxic and non-corrosive composite asphalt mixture and has excellent pavement performance, and the tensile strength, compressive strength, shear strength, aging resistance, rutting resistance and fatigue resistance of t