Abstract
It has recently been found that magnesium potassium phosphate cement (MKPC) paste coating applied on the surface of steel reinforcement can effectively retard the onset of corrosion and suppress corrosion reactions. However, the fast-setting nature of MKPC—which is a merit in repair—can be problematic in a practical engineering process of coating the steel reinforcement with MKPC paste. To address this problem, boric acid (H3BO3) was added as a retarder in an MKPC formulation to prolong the setting time. This work investigated the impact of boric acid (at 5% by weight of MgO) on the anti-corrosion performance of MKPC paste coating through a series of electrochemical (EC) tests. The results showed that the anti-corrosion performance of MKPC paste coating for a mild steel bar could be interfered with by the presence of boric acid. In the same testing situation (immersed in 3.5 wt.% NaCl corrosion solution), the polarization resistance and corrosion current density of the group including boric acid were inferior and exceeded the corrosion thresholds prior to the control group without boric acid. Meanwhile, the time constant phase in the frequency range from 1 Hz to 10 kHz was rarely observed, implying that the presence of boric acid probably impaired the formation of the passivation layer. This decrease in anti-corrosion performance of MKPC paste coating could be related to the larger volume fraction of pores in the range from 0.1 to 10 µm that are formed during the initial stage of coating formation.
Recommended Citation
F. Zhang et al., "Anti-Corrosion Performance of Magnesium Potassium Phosphate Cement Coating on Steel Reinforcement: The Effect of Boric Acid," Materials, vol. 17, no. 21, article no. 5310, MDPI, Nov 2024.
The definitive version is available at https://doi.org/10.3390/ma17215310
Department(s)
Civil, Architectural and Environmental Engineering
Publication Status
Open Access
Keywords and Phrases
anti-corrosion; boric acid; coating; magnesium potassium phosphate cement; plain round reinforcement
International Standard Serial Number (ISSN)
1996-1944
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2024 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Nov 2024
Included in
Architectural Engineering Commons, Civil Engineering Commons, Structural Engineering Commons, Structural Materials Commons
