Abstract
Exposed to aggressive environments, the rebar in reinforced concrete (RC) bridges will be corroded gradually. Durability of RC material mostly depends on the rebar corrosion behavior. In this research, influences of crack on rebar corrosion were investigated. Firstly, RC specimens with different crack number, width and spacing were prepared and the rebar corrosion was conducted through an accelerated chloride penetration method. Then, corrosion current densities of rebar were calculated from electrochemical test methods including liner polarization (LP), Tafel potentiodynamic polarization (TPP) and electrochemical impedance spectroscopy (EIS) measurements. Finally, the discussion was presented about a more reasonable electrochemical testing method for rebar corrosion in RC material. Besides, the significant influence factor among crack width, number and spacing was evaluated based on both One-way analysis of variance (One-way ANOVA) and Turkey’s honest significant difference (Turkey’s HSD) test. The results revealed that a more reasonable way to obtain corrosion current densities of rebar is combining EIS measurement with TPP measurement. Crack number shows the most significant effect on corrosion behavior of rebar, while crack spacing possesses the least one.
Highlights
Reinforced concrete (RC) is one of the most widely used materials for bridge structures
The major work of this study includes the recommendation of the reasonable electrochemical test method for rebar in RC material and quantitative analysis of the effect of crack number, width and spacing on rebar corrosion
The following conclusions were drawn: (1) Due to the electrochemical impedance spectroscopy (EIS) excluding the polarization resistance (Rp) error caused by concrete and Stern-Geary coefficient (B) from Tafel potentiodynamic polarization (TPP) reflecting the non-uniform corrosion of rebar in RC material, a more accurate electrochemical test method combining EIS with TPP measurements was recommended for rebar corrosion behavior in RC material
Summary
Reinforced concrete (RC) is one of the most widely used materials for bridge structures. In the process of bridge reinforcement, environmental problems including noise pollution, dust pollution and consumption of natural resources will occur. The corrosion of rebar in concrete is crucial to the durability of RC structures, especially in chloride aggressive environments [1,2]. Cracks will be formed due to material shrinkage, thermal gradients and repeated mechanical loading causing a higher osmotic pressure, which often leads to a higher chloride diffusion coefficient in concrete [3,4]. It is necessary to investigate corrosion behavior of rebar under the effect of crack in chloride aggressive environment [5,6,7,8]
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