Self-compacting concrete admixture and preparation method thereof

The invention discloses a self-compacting concrete admixture and a preparation method thereof. The self-compacting concrete admixture comprises the following components in parts by weight: 160-180 parts of a water reducing agent, 120-155 parts of a slump retaining agent, 20-28 parts of sodium gluconate, 0.5-1.3 parts of hydroxyl propyl cellulose, 2-4 parts of a thickener, 1-1.9 parts of an air entraining agent, 0.2-0.7 part of a defoaming agent, 10-24 parts of sodium nitrite and 80-135 parts of water; wherein the water reducing agent comprises at least one of a polycarboxylate water reducing agent and a sodium lignin sulfonate water reducing agent; the thickener comprises at least one of polyacrylamide and sodium polyacrylate; the air entraining agent comprises at least one of an alkane sulfonate-based air entraining agent, a saponin-based composite air entraining agent and a modified rosin-based thermopolymer-based air entraining agent. The self-compacting concrete admixture has the advantages of reducing se