C20-level self-compacting concrete with steel slag and recycled aggregates and preparation method of C20-level self-compacting concrete

The invention discloses C20-level self-compacting concrete with steel slag and recycled aggregates and a preparation method of the C20-level self-compacting concrete. The C20-level self-compacting concrete with the steel slag and the recycled aggregates is prepared from raw materials in parts by mass as follows: 1 part of water, 3.089 parts of natural coarse aggregates, 1.322 parts of recycled coarse aggregates, 3.822 parts of fine aggregates, 0.970-1.213 parts of cement, 1.213-1.455 parts of the steel slag, 0.609 parts of fly ash, 0.064 parts of added water and 0.00495-0.0124 parts of an additive. The concrete has good liquidity, filling performance and segregation resistance, gradual loss and strength both meet related requirements of buildings, meanwhile, the preparation method is simple, the production cost of self-compacting concrete with the same strength on year-on-year basis is reduced, the problem about treatment of the steel slag and building waste is solved, pressure of resource exhaustion is relie