Reinforcement corrosion research based on the linear polarization resistance method for coral aggregate seawater concrete in a marine environment

Bo Da (Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China)
Hongfa Yu (Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China)
Haiyan Ma (Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China)
Zhangyu Wu (Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Publication date: 3 September 2018

Abstract

Purpose

This paper aims to reduce the cost, limit the time and increase raw material source availability, coral aggregate seawater concrete (CASC) composed of coral, coral sand, seawater and cement can be widely used for the construction of ports, levees, airports and roads to achieve practical engineering values. However, the naturally porous coral structure and abundant Cl in the seawater and coral lead to extremely severe reinforcement corrosion for CASC. It is well known that Cl is the main cause of reinforcement corrosion in the marine environment. Therefore, it is necessary to research the reinforcement corrosion of CASC in the marine environment.

Design/methodology/approach

In this study, linear polarization resistance was adopted to test the linear polarization curves of reinforcement in CASC with different exposure times. Ecorr, Rp, Icorr and Vcorr were calculated according to the weak electrochemical polarization theory and Stern–Geary formula. The effects of concrete cover thickness, exposure time, reinforcement types and inhibitor on reinforcement corrosion in CASC were analysed. The reinforcement corrosion degradation rule was determined, which provided theoretical support for the durability improvement, security assessment, service life prediction and service quality control of CASC structures in marine islands and reef engineering.

Findings

The corrosion resistance was enhanced with increased concrete cover thickness, and the concrete cover thickness for organic new coated steel should be at least 5.5 cm to reduce the reinforcement corrosion risks in CASC structures. The corrosion resistance of different types of reinforcements followed the rule: 2205 duplex stainless steel > 316 stainless steel > organic new coated steel > zinc-chromium coated steel > common steel. In the early exposure stage, the anti-corrosion effectiveness of the calcium nitrate inhibitor (CN) was superior to that for the amino alcohol inhibitor (AA). With the extension of exposure time, the decreasing rate of anticorrosion effectiveness of CN was higher than that of AA.

Originality/value

Reinforcement corrosion of CASC in a marine environment was studied. Concrete cover thickness, exposure time, reinforcement type and inhibitor influenced the reinforcement corrosion were investigated. New technique of reinforcement anti-corrosion in marine engineering was proposed. Possible applications of CASC in marine engineering structures were suggested.

Keywords

Acknowledgements

The authors gratefully acknowledge the financial supports from the National Key Basic Research Development Plan of China (973 Plan) under Grant No. 2015CB655102, the National Natural Science Foundation of China under Grant No. 51508272 and Grant No. 51678304, the Natural Science Foundation of Jiangsu Province under Grants No. SBK2018041341, the Project funded by China Postdoctoral Science Foundation under Grant No. 2018M630558.

Citation

Da, B., Yu, H., Ma, H. and Wu, Z. (2018), "Reinforcement corrosion research based on the linear polarization resistance method for coral aggregate seawater concrete in a marine environment", Anti-Corrosion Methods and Materials, Vol. 65 No. 5, pp. 458-470. https://doi.org/10.1108/ACMM-03-2018-1911

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Emerald Publishing Limited

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