*Article* **Effect of Crack on Durability of RC Material under the Chloride Aggressive Environment**

#### **Yongchun Cheng, Yuwei Zhang, Guojin Tan \* and Yubo Jiao**

College of Transportation, Jilin University, Changchun 130025, Jilin, China; chengyc@jlu.edu.cn (Y.C.); ywzhang15@mails.jlu.edu.cn (Y.Z.); jiaoyb@jlu.edu.cn (Y.J.)

**\*** Correspondence: tgj@jlu.edu.cn; Tel.: +86-0431-8509-5446

Received: 5 January 2018; Accepted: 4 February 2018; Published: 7 February 2018

**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.

**Keywords:** rebar corrosion; cracked RC material; aggressive environment; durability; electrochemical test methods
