(1)Shelling. The cement mortar leveling layer and the concrete joint surface are peeled off, and the adhesion is poor. The simple method of judging is to use a small hammer or metal object to strike the sound of an empty hollowing. If the entire joint surface is peeled off, the mortar leveling layer should be completely removed and the surface should be resurfaced. If only partial peeling is used, it can be repaired by means of a special infusion material perfusion method.(2) Crack. A "V" shaped groove of about 1 cm width was cut with an electric cutter along the crack portion and repaired with a middle layer material.(3) Gap. When there are pits or notches on the surface of the base layer, the dust and loose materials are first removed and smoothed with middle layer material.
(4) Poor strength. Due to insufficient cement labeling, unreasonable mortar ratio or poor curing, the strength is poor and the surface is loose. The concrete should be re-cast after removal or strengthened with concrete reinforced base oil.