SA concrete fine crack repair agent is a kind of solvent-free low viscosity inorganic liquid, its low viscosity ensures the permeability, can penetrate into the small cracks of concrete, in the water in the air or the water in the capillary pores of concrete, reaction with the free calcium ions in concrete, generate calcium silicate gel, fill concrete small cracks and capillary channels.The catalyst can accelerate the speed of this reaction, so that a large number of gel bodies can be generated in a short time and shorten the construction period.