Passivation of reinforcing steel in reactive MgO cement blended with Portland cement

Tangwei Mi; En-Hua Yang; Cise Unluer

doi:10.1016/j.cemconcomp.2023.105269

Passivation of reinforcing steel in reactive MgO cement blended with Portland cement

Tangwei Mi
, En-Hua Yang
, Cise Unluer (Lead / Corresponding author)

Research output: Contribution to journal › Article › peer-review

14 Citations (Scopus)

190 Downloads (Pure)

Abstract

Reactive MgO cement (RMC) has an ability to gain strength by carbonation. One of the main concerns in RMC systems is the potential corrosion of reinforcing steel in structural applications. This study evaluated the feasibility of replacing small proportions of RMC with Portland cement (PC) to promote the passivation of reinforcing steel. Reinforcing steels embedded in RMC with different proportions of PC were investigated by electrochemical measurements and microstructural analysis. Pore solutions extracted from these pastes were evaluated for their chemical compositions. Inclusion of ≥2% PC enabled the passivation of steel. Passive film forming in RMC-PC blends consisted of Fe₃O₄ and Mg(OH)₂, which was thicker than those in pure PC mixes. The formation of passive film was mainly attributed to the increased pH of the pore solution, which reached over 12 in RMC mixes containing only 2% PC. These findings highlighted the potential of using RMC mixes in reinforced concrete applications.

Original language	English
Article number	105269
Number of pages	10
Journal	Cement and Concrete Composites
Volume	143
Early online date	23 Aug 2023
DOIs	https://doi.org/10.1016/j.cemconcomp.2023.105269
Publication status	Published - Oct 2023

Keywords

Blended cement
Electrochemical properties
MgO
Pore solution
Surface layer

ASJC Scopus subject areas

Building and Construction
General Materials Science

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10.1016/j.cemconcomp.2023.105269Licence: CC BY

Final Published VersionFinal published version, 8.58 MBLicence: CC BY

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title = "Passivation of reinforcing steel in reactive MgO cement blended with Portland cement",

abstract = "Reactive MgO cement (RMC) has an ability to gain strength by carbonation. One of the main concerns in RMC systems is the potential corrosion of reinforcing steel in structural applications. This study evaluated the feasibility of replacing small proportions of RMC with Portland cement (PC) to promote the passivation of reinforcing steel. Reinforcing steels embedded in RMC with different proportions of PC were investigated by electrochemical measurements and microstructural analysis. Pore solutions extracted from these pastes were evaluated for their chemical compositions. Inclusion of ≥2\% PC enabled the passivation of steel. Passive film forming in RMC-PC blends consisted of Fe3O4 and Mg(OH)2, which was thicker than those in pure PC mixes. The formation of passive film was mainly attributed to the increased pH of the pore solution, which reached over 12 in RMC mixes containing only 2\% PC. These findings highlighted the potential of using RMC mixes in reinforced concrete applications.",

keywords = "Blended cement, Electrochemical properties, MgO, Pore solution, Surface layer",

author = "Tangwei Mi and En-Hua Yang and Cise Unluer",

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doi = "10.1016/j.cemconcomp.2023.105269",

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TY - JOUR

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AU - Mi, Tangwei

AU - Yang, En-Hua

AU - Unluer, Cise

PY - 2023/10

Y1 - 2023/10

N2 - Reactive MgO cement (RMC) has an ability to gain strength by carbonation. One of the main concerns in RMC systems is the potential corrosion of reinforcing steel in structural applications. This study evaluated the feasibility of replacing small proportions of RMC with Portland cement (PC) to promote the passivation of reinforcing steel. Reinforcing steels embedded in RMC with different proportions of PC were investigated by electrochemical measurements and microstructural analysis. Pore solutions extracted from these pastes were evaluated for their chemical compositions. Inclusion of ≥2% PC enabled the passivation of steel. Passive film forming in RMC-PC blends consisted of Fe3O4 and Mg(OH)2, which was thicker than those in pure PC mixes. The formation of passive film was mainly attributed to the increased pH of the pore solution, which reached over 12 in RMC mixes containing only 2% PC. These findings highlighted the potential of using RMC mixes in reinforced concrete applications.

AB - Reactive MgO cement (RMC) has an ability to gain strength by carbonation. One of the main concerns in RMC systems is the potential corrosion of reinforcing steel in structural applications. This study evaluated the feasibility of replacing small proportions of RMC with Portland cement (PC) to promote the passivation of reinforcing steel. Reinforcing steels embedded in RMC with different proportions of PC were investigated by electrochemical measurements and microstructural analysis. Pore solutions extracted from these pastes were evaluated for their chemical compositions. Inclusion of ≥2% PC enabled the passivation of steel. Passive film forming in RMC-PC blends consisted of Fe3O4 and Mg(OH)2, which was thicker than those in pure PC mixes. The formation of passive film was mainly attributed to the increased pH of the pore solution, which reached over 12 in RMC mixes containing only 2% PC. These findings highlighted the potential of using RMC mixes in reinforced concrete applications.

KW - Blended cement

KW - Electrochemical properties

KW - MgO

KW - Pore solution

KW - Surface layer

UR - https://www.scopus.com/pages/publications/85169044111

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DO - 10.1016/j.cemconcomp.2023.105269

M3 - Article

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SN - 0958-9465

VL - 143

JO - Cement and Concrete Composites

JF - Cement and Concrete Composites

M1 - 105269

ER -

Passivation of reinforcing steel in reactive MgO cement blended with Portland cement

Abstract

Keywords

ASJC Scopus subject areas

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