It is necessary to distinguish the types of cracks. If it is a thermal expansion crack or a shallow expansion crack, and the depth is less than 2mm, it doesn't matter if it doesn't develop vertically and horizontally, so it can be left untreated.
If it is a structural crack, it is recommended to repair it with cement mortar mixed with epoxy resin.
If the surface cement slurry is too thick, it is recommended to clean the surface and repair it again.
To measure cracks, water them with black ink, and then chisel a crack for observation.
In the subsequent construction, quality control, especially the control of masonry protective layer, should be strengthened. Most cracks are caused by too many protective layers. Especially for cantilever cast-in-place box girder, attention should be paid to the cracks near the anchor head and prestressed pipeline. It is suggested to chisel them out directly and then repair them with epoxy resin.