Corrosion behavior of reinforcing bar in magnesium phosphate cement based on polarization curve

• Published in: Sadhana (Bangalore) Vol. 45; no. 1
• Main Authors: Jun, Li, Yongsheng, Ji, Zhishan, Xu
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01-12-2020; Springer Nature B.V
• Subjects: Ammonium phosphates; Bars; Cement reinforcements; Coordination compounds; Corrosion; Corrosion mechanisms; Corrosion rate; Corrosion resistance; Engineering; Magnesium phosphate; Morphology; Open circuit voltage; Optical microscopes; Polarization; Rebar; Resistance factors; Workstations; pH; MPC; rust; polarization curve; electrochemistry
• ISSN: 0256-2499; 0973-7677
• DOI: 10.1007/s12046-019-1252-4

Apart from focusing on the analysis of the characteristics of reinforcing bars during corrosion, such as open circuit potential and polarization, the study also engages in the investigation of their corrosion in magnesium phosphate cement (MPC). For a more comprehensive understanding of the rusting performances, a comparison was made by an electrochemical workstation between the reinforcing bars in the MPC system and in the ordinary cement. Meanwhile, under an optical microscope, an observation was conducted on the corrosion morphology in MPC at different ages of concrete while during MPC hydration, an exploration based on pH changes and polarization curve theory was carried out to learn about the mechanism of the resistance of the reinforcing bars in MPC to corrosion. Despite their extremely slow rate, corrosion behaviors were practically found in the reinforcing bars in MPC. Both the changes in pH and the formation of ammonium phosphate metal complex in the weak base were considered in the study to be the control factors for the resistance of reinforcing bars in MPC to corrosion.