Early-strength anti-crack concrete for assembly and preparation method thereof

The invention provides an early-strength anti-crack concrete for assembly and a preparation method thereof, and the early-strength anti-crack concrete is prepared from ordinary Portland cement, fly ash, sand, gravel, a composite admixture, steel fiber and water, the composite admixture is prepared from an early strength component, an expanding agent, a water reducing agent, a defoaming agent, a delayed coagulation component, a modified nano material, high-performance polymer fibers and organic microspheres, wherein the modified nano material is prepared from carbon nanotubes, nano silicon powder and nano titanium oxide. By using the coagulant and the early strength agent, the concrete can quickly form calcium silicate hydrate in the early stage, and the early compressive strength of the concrete is improved. Meanwhile, magnesium hydroxide and calcium hydroxide in the gelatinoid and generated calcium gluconate and calcium citrate are beneficial for improving the durability of the concrete, the cracking risk is