Development And Application Of High Performance Dual-effect Antirust And Realkalinization Electrolyte Solution

Electrochemical rebalancing technology is a new technology used for repairing the corrosion damage caused by carbonated reinforced concrete.And the alkalinity of concrete can be effectively improved and the corrosion activity of reinforcing bars can be reduced by re-alkalization technology,but the ability however,of long-term effective corrosion inhibition of reinforcing bars,remains to be discussed.In order to further reduce the corrosion activity of reinforcing steel bar and improve the durability of rebar alkalization technology,this paper proposes to develop high performance dual-effect corrosion inhibitors and rebalancing electrolyte solution.The electro migration type corrosion inhibiting agent is introduced into the rebalancing electrolyte solution to improve the alkalinity of concrete and migrate the corrosion inhibiting agent to the surface of reinforcing steel bar to further improve the alkalinity.It is also called the double-effect method of re-alkalization and corrosion inhibition.This method is a new way to prolong the life of carbonated reinforced concrete.In this paper,the corrosion inhibition performance of three kinds of rust inhibitors;ethanolamine,triethylenetetramine,N,N-dimethylethanolamine which were placed in simulated carbonated concrete pore fluid was studied,and the corrosion potential and corrosion current density of steel bars in simulated solution were tracked to predict the corrosion inhibition performance of rust inhibitors in carbonated concrete.Corrosion inhibition performance based on rust inhibitors and electrolytes recommended by relevant technical specifications were predicted.Four kinds of dual-effect re-alkalization corrosion inhibitor electrolytes were prepared preliminarily,and the carbonated reinforced concrete specimens were treated with re-alkalization-corrosion inhibitors.The pH value of the concrete,the change of corrosion potential and current density of the steel bar,the migration ability and retention of the corrosion inhibitor in the concrete protective layer were studied,and the four kinds of dual-effect re-alkalization corrosion inhibitor electrolytes were analyzed.Based on the above research results,a high performance dual-effect electrolyte solution was developed,and a local field test of dual-effect electrolyte solution was carried out in Daodeqiao,Pan’an County,Zhejiang Province.The main work and research conclusions of this paper are as follows:（1）The corrosion inhibition performance of the corrosion inhibitor in simulated carbonated concrete pore fluid shows that ethanolamine and N,N-dimethylethanolamine have certain corrosion inhibition ability when the solution pH=9 and 10.5,while triethylenetetramine has no corrosion inhibition effect,on the contrary,it accelerates the corrosion of steel bars.With the increase of pH value of simulated solution,the rust inhibition effect of ethanolamine and N,N-dimethyl ethanolamine is improved.When the concentration is 0.5 mol/L,ethanolamine has better corrosion inhibition efficiency than N,N-dimethylethanolamine in the pore fluid of carbonated concrete.（2）Based on the corrosion inhibition performance of corrosion inhibitors in simulated carbonated concrete solution,four dual-effect re-alkalization corrosion inhibitor electrolytes were initially allocated,namely A（40g/L K₂CO₃,0.5mol/L ethanolamine）,B（40g/L K₂CO₃,1mol/L ethanolamine）,C（40g/L K₂CO₃,0.5mol/L,N-dimethylethanolamine）,D（40g/L K₂CO₃,1mol/L,N-dimethylethanolamine）,and tetramethanolamine.A double-effect re-alkalization and corrosion inhibition electrolyte solution was used to repair the reinforced concrete specimens.A blank control group was set up in the experiment.The traditional re-alkalization electrolyte solution（40g/L K₂CO₃）was used to repair the reinforced concrete specimens with a current of 1A per unit surface area（m2）and a total electric capacity of 200 A.h.（3）The pH value of the concrete protective layer around the reinforcing bar is increased to more than 10 after the treatment of re-alkalization-corrosion inhibition.Among them,the effect of electrolyte C is the best,and the pH value of the concrete protective layer around the reinforcing bar reaches 12.4.After the treatment of re-alkalization-corrosion inhibition,the corrosion potential of the reinforcing bar is increased and the corrosion current density of the reinforcing bar is reduced.Among them,electrolyte C has the best effect,which increases 508mV and decreases 0.62μA/cm² of corrosion current density compared with the traditional electrolyte solution.Compared with the traditional electrolyte solution,the corrosion potential increases by 48 mV and the corrosion current density decreases by 0.1μA/cm² after two months of repair.Ethanolamine and N,N-dimethylethanol have certain migration in the concrete protective layer,ability and retention capacity under the same conditions as the migration energy of ethanolamine in carbonated concrete.（4）In this paper,a high-performance dual-effect re-alkalization corrosion inhibitor electrolyte solution was developed,and a local field test was carried out in Daodeqiao,Pan’an County,Zhejiang Province.The results show that the developed high-performance dual-effect re-alkalization corrosion inhibitor electrolyte solution can increase the corrosion potential of steel bar faster than the traditional electrolyte solution,and will not change the surface of the component.The color and durability need to be further studied.In this paper,the development of high performance double effect realkalization corrosion liquid electrolyte,made it possible to realkalize corrosion to improve the durability of carbonated reinforced concrete.