The quality problems of the steel bars themselves lead to rust stains on the surface of the steel bars, which further develop into a rust layer on the entire surface of the steel bars, resulting in expansion of the steel bars, reduced adhesion between the steel bars and the concrete, and separation from the concrete.
The concrete itself undergoes damage, resulting in cracks along the reinforcement and detachment of the concrete.
At this point, the corrosion and expansion of steel bars will exacerbate the development of concrete cracks.
As shown in the following figure:.