A study on the deterioration of interfacial bonding properties of chloride-contaminated reinforced concrete after electrochemical chloride extraction treatment

摘要

This paper adopted magnesium phosphate cement (MPC) bonding CFRP (MPC-CFRP) as anode materials and the effects of ions distribution, interfacial composition and microstructure on the deterioration of interfacial bonding properties of chloride-contaminated reinforced concrete after electrochemical chloride extraction (ECE) treatment were systemically studied. The results showed that MPC-CFRP materials can be used as the ECE anode and achieve the chloride removal of concrete. Current density is the main influence factor for ECE treatment, the influence of temperature on ECE is small. ECE treatment could effectively remove the chloride ions and decrease the corrosion risk of rebar in concrete. However, ECE treatment altered the interfacial composition and microstructure. After ECE treatment, the contents of K+, Na+ and OH- around the rebar increased significantly, new alkali metal ions rich cementitious phase and directional arrangement of lamellar hydration product with high Ca/Si ratio were formed. Besides, ECE treatment caused the cracking and decomposition of C-S-H in rebar-concrete interface. As a result, the interfacial bond strength decreased. Taking all these factors into consideration, the relatively better condition for ECE treatment is 2 A/m(2). (C) 2018 Elsevier Ltd. All rights reserved.