Chloride ion concentration distribution characteristics within concrete covering-layer considering the reinforcement bar presence. (1st February 2019)

• Record Type: Journal Article
• Authors: Wang, Yuanzhan; Liu, Chenxi; Li, Qingmei; Wu, Linjian
• Is Part Of: Ocean engineering. Volume 173(2019)
• Page Start: 608
• Page End: 616
• Publication Date: 2019-02-01
• Subjects: Chloride concentration prediction -- Reinforcement bar effect -- Covering-layer; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2019.01.048
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Reinforcement bar corrosion induced by chloride ions ingress is one of the dominating causes for the deterioration of reinforced concrete structures in salty environment. Thus, it is particularly important to accurately predict chloride concentration in concretes and evaluate the structural service life. This paper presents the results of an indoor experimental investigation on chloride diffusion in plain and reinforced mortar specimens exposed to tidal zone, which is simulated by a self-design marine environment automatic simulation device. Concrete covering-layer was divided into major influence area (MIA) and secondary influence area (SIA) to accurately describe the chloride ion concentration distribution characteristics. MIA is the region affected by direct and indirect blocking effect of reinforcement bar, while SIA is the area only influenced by the indirect one. Also, the relative influence coefficient C re was defined to measure the impact of reinforcement bar on the chloride ion ingress. The results indicate that indirect blocking effect of rebar resulting from changes of material properties is the major cause for the chloride ion concentration distribution in SIA and it is only relative to the diffusion depth. Whereas, direct blocking effect of bar caused by physical obstruction to accumulate chloride ions contributes most to the chloride increase in MIA and it is correlated to the diffusion depth, exposure time and diameter of bar. Finally, an empirical prediction model of chloride concentration in concrete covering-layer considering the effect of reinforcement presence is proposed. Highlights: A self-designed artificial marine environment automatic simulation device can simulate the actual tidal fluctuation. The influence area of rebar on chloride distribution was extended to concrete covering-layer not merely the apex of rebar. An empirical model predicting chloride concentration in covering-layer of reinforced concrete was proposed.