The invention discloses a
cement-based permeable
nanocrystal self-repairing waterproof admixture and a preparation method thereof, and belongs to the technical field of building materials. The admixture is composed of quick-hardening sulphoaluminate
cement,
nano silicon dioxide, nano
anhydrous calcium carbonate, bacillus pasteurii and the like, nanoparticles are subjected to
surface modification through a
silane coupling agent, microorganisms are embedded through
sodium alginate to form microcapsules, the mineral activity is improved in combination with ball milling treatment, and a chemical expansion and
microorganism mineralization double-repair
system is constructed. After the nano-
powder is modified, the
dispersity is improved by 60%, pores of 10-50 nm can be filled, the
survival rate of spores can reach 85% or above through microbial embedding, activation is conducted within 48 hours when the nano-
powder meets water, the self-repairing efficiency of a double-repairing
system on cracks of 0.1-0.3 mm is larger than or equal to 90%, and the anti-permeability pressure
recovery rate after repairing is larger than or equal to 80%. The 7d anti-permeability pressure of the product is greater than or equal to 1.2 MPa, and the 28d anti-permeability pressure of the product is greater than or equal to 1.6 MPa, and the product has early-stage rapid repairing and long-term waterproof performance, solves the problems of insufficient durability and low self-repairing efficiency of a traditional material, and is suitable for underground
engineering, bridges, tunnels and other scenes.