Reinforced concrete often causes steel rust and concrete peeling due to the external environment; for example, vehicle impact, insufficient protective layer, neutralization of concrete, misuse of sea sand and environmental factors can cause steel rust or concrete cracks to be flooded. Cause the steel bars to rust.
　　The methods to prevent rusting of steel bars can be divided into strengthening concrete quality and protecting steel bars to protect concrete structures. Of course, if concrete can control some components, such as water, chloride ions, oxygen, carbon dioxide, etc., to penetrate into it, or even to the surface of the steel bar, or to truly implement the construction quality of the reinforced concrete structure project, the steel bar will be able to achieve this without any further protection. Use quality.
　　 However, these influencing factors are often seen everywhere when the project is in progress. Therefore, the steel bars should be protected as much as possible.
　　Rebar protection, generally there are two kinds of hot-dip galvanizing and epoxy resin coating.
These two methods have their own advantages and disadvantages. A large number of experimental results show that the processing performance of the hot-dip galvanized steel bar in the field is better. It can exert its superior characteristics in engineering and improve the reliability and corrosion resistance of the project. , Make the project more economical.

 

　　Alternatives to the thickness of the concrete protective layer still need to be used correctly and appropriately, and the combination of zinc and concrete includes:
　　 (1) The reaction of zinc with Ca(OH)2.
　　 (2) The pure state of the zinc surface.
　　 (3) The production of hydrogen.
Because concrete has a high alkaline environment (PH=12.5～13.2), a pure state protective layer is formed on the surface of steel bars to prevent corrosion of steel bars. Just like it protects steel bars, zinc is an amphoteric element (which can interact with acid, Alkali reacts), the lowest corrosion rate is at PH=12.5, which is equivalent to the PH value of cement hydration.
　　 And zinc will dissolve when PH=8～12.5, after the concrete hardens, the reaction of zinc with alkaline environment can stop.
The net reaction of zinc and calcium hydroxide forms a zinc-passivated zinc-calcium hydroxide barrier layer, but it is also accompanied by the generation of hydrogen. Adding a small amount of chromate (70-100ppm) to the cement can overcome the generation of hydrogen, and it is only necessary to prevent the construction personnel from being injured by chromic acid or chromate during work.