Study On Corrosion Behavior Of Reinforced Concrete In Chloride And Its Coupling Solution

The study on the durability of reinforced concrete structure is one of the major problems in the construction field currently, The premature corrosion of the steel makes the structure premature failure, it will inevitably lead to material waste, and cause significant economic losses to the national economy. Therefore in the design of reinforced concrete reinforced protection became a top priority. There are more research results on the corrosion of steel reinforcing bar in reinforced concrete structure, but there is still no a complete system of theory study, and a qualitative and quantitative analysis of the corrosion of steel in chloride and coupled environment has not made, especially the effect of sulfate on steel in chlorine environment not a conclusion.For the coupled environment of chloride and sulfate in groundwater has corrosion effect on steel in reinforced concrete. the experiment process of this paper can be summarized as "one’3’,two’4’and two’5’ ".One "3" means that the subject selected the water-cement ratio is three kinds of reinforced concrete specimens with the water-cement ratio of 0.25,0.35,0.45;Two "4" is refers to the subject chose four different concentrations of salt solution and using four kinds of test methods. 4 different concentrations of salt solution specifically: solution A is 2000 mg / L NaCl solution, solution B is 2000 mg / L NaCl and 500 mg / L Na₂SO₄ coupled solution, solution C is a coupled solution of 2000mg/L NaCl and 5000mg/L Na₂SO₄, solution D is a coupled solution 2000mg/L NaCl and 50000mg/L Na₂SO₄; four experimental methods specific are refers to the electrochemical method, Electric flux method, resistance method and micro analysis method.Two "5" means that this test take every 60 days as an experimental cycle, and experienced a total of five cycles; this project finally got five conclusions. Namely:（1） resistance as a non-destructive and sustainable experimental methods,it can be applied in the field of steel corrosion;（2）Relative to the other two mix, The corrosion resistance of steel is the strongest of the specimen, and the water cement ratio is 0.35（3） the rate of reinforcement corrosion in chloride environments is developed by the way of "increase- decrease- increase", spiral increase;（4） Sulphate corrosion of reinforcing steel bar in chlorine salt solution,is associated with the concentration of sulfate, when the concentration of sulfate is much lower than the concentration of chlorine sulphate salt, Sulphate corrosion of reinforcement, but this promotion will decrease with time; when the concentration of sulfate and chlorine concentration equal or higher than chlorine salt, sulfate on the steel corrosion in chloride have an inhibition, this inhibition will be enhanced with the sulfate concentration, and this inhibition with time development enhanced;（5） Lanzhou groundwater environment have medium corrosion effect on reinforcing steel bar.In summary,the subject has recorded the corrosion process of steel in chloride as well as the coupling conditions, and qualitative and quantitative analysis of the steel corrosion process in various environments were made. Select appropriate concrete mix proportion for durability requirements in Lanzhou area; Analysis corrosion mechanism of steel in chloride solution; analysis the effect of sulfate on steel corrosion in chloride environment; All test methods verifies each other, in particular, to verify whether the resistance method is suitable for application in the field of steel corrosion.