The invention relates to the technical field of roadbed materials, in particular to a composite filling material and a preparation method and application thereof. The composite filling material provided by the invention is prepared from the following raw materials in parts by weight: 18 to 26 parts of pretreated
phosphogypsum, 30 to 45 parts of pretreated household garbage
incineration bottom ash, 8 to 18 parts of alkaline excitation material, 6 to 20 parts of aluminum-
silicon material, 5 to 25 parts of aggregate and 1 to 4 parts of
sodium sulfate aqueous solution, the pretreatment of the
phosphogypsum comprises
lime milk aging treatment; the pretreated household garbage
incineration bottom ash comprises gelation active
fine powder and structural aggregate. The composite filling material formed by taking the ardealite, the household garbage
incineration bottom ash, the alkaline excitation material and the aluminum-
silicon material as main raw materials is high in industrial
solid waste mixing amount, stable in performance and environment-friendly, reduces the
pollutant leaching risk, is suitable for roadbed structures such as an embankment filling layer, a semi-rigid base layer and a flexible
subbase layer, and has a wide application prospect. And the benefit is obvious.