The operating method of epoxy resin coated steel bars should pay attention to these problems
Epoxy resin coated steel bar production: different from the usual epoxy resin coating applied to the steel bar surface, the epoxy resin coated steel bar is made by electrostatic powder spraying, and the steel bar surface is coated in the factory.
The United States has successively tested 56 various coating materials, and finally selected this thermosetting electrostatic spray epoxy powder coating material and manufacturing process.
Cohesive force and influence on concrete binding force: The unique properties of epoxy resin powder and the electrostatic spraying process can ensure good adhesion between the coating and the base steel bar, good tensile and bending resistance, and a short radius of 180° bending. There is still no cracks, which is difficult to achieve with other coatings.
What’s important is that the bond strength of epoxy-coated steel bars and concrete has the smallest decrease (relevant standards allow a 10% reduction), while other coatings may greatly reduce the bond strength (even more than 50%) (China's standard It is stipulated that coatings cannot be applied to the surface of steel bars casually, also because general coatings can significantly reduce the bond between steel bars and concrete).
Epoxy powder coating also has the following properties: a. Alkali resistance. Can withstand the high alkaline environment of concrete for a long time (pH=12.5～13.5); b. Chemical resistance.
Because the epoxy resin powder coating has high chemical stability and corrosion resistance, and the film layer is impermeable, it can prevent corrosive media such as water, oxygen, and chloride from contacting steel bars; c. Elasticity and friction resistance All are good.
Epoxy resin coated steel bars have many advantages and advantages. As a new technology, it has been developed rapidly abroad. However, problems and deficiencies have also been found in use, resulting in engineering accidents.
In addition to the quality of the project, it has also been found that there are quality problems and problems in the use of epoxy-coated steel bars. The main problem is whether it can ensure the integrity of the epoxy coating on the surface of the steel bars.