Effects of Various Corrosive Ions on Metakaolin Concrete

In order to study and verify if the three corrosive irons of SO42−, Mg2+, and Cl− could promote or inhibit each other in concrete corrosion as time goes by, we take Metakaolin (MK) as the research object to explore the interaction mechanism among ions by testing the physical and mechanical propertie...

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Bibliographic Details
Published inCrystals (Basel) Vol. 11; no. 9; p. 1108
Main Authors Chen, Xupeng, Sun, Zhuowen, Pang, Jianyong
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.09.2021
Subjects
Aggregates
Cement
complex ion
Concrete mixing
Corrosion
corrosion degradation
dry-wet alternation
Ettringite
Gypsum
Magnesium hydroxide
Mechanical properties
Metakaolin
microstructure
Phase composition
Physical properties
China
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Summary:In order to study and verify if the three corrosive irons of SO42−, Mg2+, and Cl− could promote or inhibit each other in concrete corrosion as time goes by, we take Metakaolin (MK) as the research object to explore the interaction mechanism among ions by testing the physical and mechanical properties, the ion content, the phase composition, and the microstructural changes of the MK concrete under the action of various ion combinations. The results show that during the initial and middle stages of the corrosion (40–80 days), SO42− and Mg2+ are in reciprocal inhibition relation, Cl− could inhibit the action of SO42−, and Mg2+ could promote the diffusion of Cl−. However, at the final stage of corrosion (120 days), SO42− and Mg2+ could mutually promote each other, and both irons could promote the diffusion of Cl−. Mg2+ could mainly produce magnesium hydroxide and M-S-H inside the concrete, SO42− mainly generates the ettringite and gypsum, while Cl− mainly produces Friedel salt and NaCl crystal.
ISSN:2073-4352
2073-4352
DOI:10.3390/cryst11091108