Recycled concrete based on lime-fly ash gravel base old material and preparation method thereof

The invention discloses recycled concrete based on a lime-fly ash gravel base old material and a preparation method of the recycled concrete. The recycled concrete is prepared from the following raw materials in parts by weight: 47.5 to 56.4 parts of lime-fly ash gravel old material recycled coarse aggregate, 25.7 to 31.4 parts of lime-fly ash gravel old material recycled fine aggregate, 8.25 to 9.75 parts of lime-fly ash gravel old material recycled powder, 2.75 to 3.25 parts of fly ash, 0.6 to 1.1 parts of sodium hydroxide, 2.1 to 3.2 parts of sodium silicate, 0.25 to 0.3 part of sodium phosphate and 1 to 1.6 parts of water. The preparation method comprises the following steps of: weighing sodium hydroxide, adding water, and stirring to obtain a sodium hydroxide solution; screening the lime-fly ash gravel old material recycled coarse aggregate and fine aggregate; weighing required raw materials and stirring; dissolving sodium phosphate in a sodium hydroxide solution, adding the dry blend and sodium silicate