▎ 摘　　要

NOVELTY - A composite asphalt modifier comprises graphene microgel modified by polyurethane oligomer and styrene-butadiene-styrene (SBS) modifier composition in the weight ratio of 0.03-1.5:3-15. USE - Composite asphalt modifier for obtaining compound modified asphalt (claimed). ADVANTAGE - The compound modified asphalt formed using composite asphalt modifier has high toughness at low temperature. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of composite asphalt modifier, which involves mixing polyurethane oligomer-modified graphene microparticles and SBS modifier particles, and stirring at 150-200 degrees C for 1-2 hours; and (2) application of composite asphalt modifier. The composite asphalt modifier is mixed with matrix asphalt, and stirred at 150-200 degrees C for 1-2 hours, to obtain compound modified asphalt.