Electrochemical Chloride Extraction Using By Developed High Performance Conductive Cement Based Anode Materials

With the development of subway construction and underground space in coastal city,concrete engineering in the environment of corrosive ions increase gradually,corrosion damage case of marine concrete structure appear constantly.Compared with the traditional way of the chloride,Electrochemical desalination is an effective and nondestructive measure to govern chloride ion invasion and improve the performance of concrete durability.This study through contrast test of varieties of conductive phases,use conductive cement base material's resistivity?strength and toughness as control index,develop carbon fiber high-performance conductive cement based anode material.Analysis the influence of current density ? electrolyte solution on efficiency of electrochemical chloride extraction and performance of concrete,put forward the method of electrochemical chloride that use conductive cement based materials as anode.The main research contents are as follows:?1?The test use carbon fiber as a conductive phase product conductive cement base material,study the physical and mechanical properties of carbon fiber conductive cement base material through resistivity?compressive strength?flexural strength?fracture energy and drying shrinkage,discuss the influence of SAP on resistivity and shrinkage of conductive cement based material,develop high-performance conductive cement based anode material.?2?The test use metal net as a conductive phase,study the influence of electrolyte solution,current density,protection layer thickness and mix ratio on the efficiency of electrochemical dechlorination.Ordinary carbon steel and corrosion resistant steel are chosen to study the influence of reinforcement type on concrete before and after chloride.It also analysis the microstructure evolution of concrete before and after electrochemical dechlorination.Experimental results show that electrochemical dechlorination efficiency increased with the increase of current density,the best current density is 2A/m²,electrolyte solution is saturated Ca?OH?₂ solution;Cover thickness and compactness of concrete will make chlorine removal rate decline;After dechlorination,content of Ca?OH?₂ and porosity increase obviously,there is no obvious hydration product;different reinforced type has no obvious influence on the chloride removal efficiency.?3?In order to discuss conductive layer thickness' s influence on chlorine removal rate,this this study choose high performance conductive cement based materials as anode,current density is 2A/m²,conductive layer thickness is 10 mm ? 20 mm and 30mm.At the same time,it test the type of concrete andreinforcement,concrete protective layer thickness' quantitative influence law of electrochemical dechlorination efficiency.After electrochemical chloride extraction,it analysis microstructure and composition evolution through the technical means of SEM?XRE?TG and so on.The results shows that reduce conductive cement-base material coating thickness can effectively reduce the accumulation of chlorine ion in concrete interface area conductive cement base material,the best coating thickness is 10 mm;With the increase of protective layer thickness and compactness,chloride removal efficiencydecrease gradually;After dechiorination the content of Ca?OH?₂ near the rebar increase;SEM results show that the adhesion stress of concrete and conductive cement base material is in good condition,line scanning shows that chloride ion content reduce gradually from the concrete to the conductive cement base material;In conductive cement base material,the carbon fiber lap well,content of Ca?OH?₂ increase,microstructure has no obvious degradation phenomenon.