Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars

Concrete spalling is one of the most common types of damage encountered in RC structures. Concrete spalling is caused by corrosion of steel reinforcement within the RC due to carbonation and/or chloride contamination. A simple patch repair work is a common technique used to reapply concrete at s...

Full description

Saved in:
Bibliographic Details
Main Author: Christian, Alvin
Other Authors: Tan Kang Hai
Format: Final Year Project
Language:English
Published: Nanyang Technological University 2023
Subjects:
Online Access:https://hdl.handle.net/10356/168308
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-168308
record_format dspace
spelling sg-ntu-dr.10356-1683082023-06-16T15:35:02Z Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars Christian, Alvin Tan Kang Hai School of Civil and Environmental Engineering CKHTAN@ntu.edu.sg Engineering::Civil engineering Concrete spalling is one of the most common types of damage encountered in RC structures. Concrete spalling is caused by corrosion of steel reinforcement within the RC due to carbonation and/or chloride contamination. A simple patch repair work is a common technique used to reapply concrete at spalling area. However, cracks within the concrete would start to form within a month after the application of patch repair. This is because the application of patch repair inadvertently introduces an additional corrosion mechanism. Steel reinforcement corrosion can be significantly reduced by implementing sacrificial anodes which are made from less noble materials than steel reinforcement to divert majority of corrosion activity to the anodes. In this study, the effect of zinc sacrificial anodes to RC slabs with patch repair work was studied. The microcell and macrocell corrosion of both the steel reinforcement and zinc sacrificial anodes within four RC slabs with different sacrificial anode arrangements were measured to determine the most effective arrangement of zinc sacrificial anodes in protecting the steel reinforcement. Two RC slabs have sacrificial anodes installed in the patch work area with one slab having a single 300 mm × 50 mm × 10 mm zinc plate placed in the centre of the patch work, while the other slab having twelve 25 mm × 50 mm × 10 mm zinc plates spread evenly within the patch work. The last RC slab would have twelve 25 mm × 50 mm × 10 mm zinc plates installed within the corroded area surrounding the patch work area. Linear Polarisation Resistance and Galvanic Coupling were techniques used to measure the magnitude of microcell and macrocell corrosion current density, respectively. It was found out that patch repair mix applied to RC slabs lowers corrosion potential value. Subsequently, the corrosion potential difference between steel reinforcement outside and within the patch area increases and thus induces an additional macrocell corrosion. Furthermore, the highest amount of macrocell corrosion can be encountered at steel segments near the patch repair area. Compared with each sample, it was discovered that zinc sacrificial anodes installed within areas with high level of chloride contamination provided the best protection for the steel reinforcement against corrosion damage. Bachelor of Engineering (Civil) 2023-06-12T00:18:28Z 2023-06-12T00:18:28Z 2023 Final Year Project (FYP) Christian, A. (2023). Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/168308 https://hdl.handle.net/10356/168308 en CT-04 application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Civil engineering
spellingShingle Engineering::Civil engineering
Christian, Alvin
Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
description Concrete spalling is one of the most common types of damage encountered in RC structures. Concrete spalling is caused by corrosion of steel reinforcement within the RC due to carbonation and/or chloride contamination. A simple patch repair work is a common technique used to reapply concrete at spalling area. However, cracks within the concrete would start to form within a month after the application of patch repair. This is because the application of patch repair inadvertently introduces an additional corrosion mechanism. Steel reinforcement corrosion can be significantly reduced by implementing sacrificial anodes which are made from less noble materials than steel reinforcement to divert majority of corrosion activity to the anodes. In this study, the effect of zinc sacrificial anodes to RC slabs with patch repair work was studied. The microcell and macrocell corrosion of both the steel reinforcement and zinc sacrificial anodes within four RC slabs with different sacrificial anode arrangements were measured to determine the most effective arrangement of zinc sacrificial anodes in protecting the steel reinforcement. Two RC slabs have sacrificial anodes installed in the patch work area with one slab having a single 300 mm × 50 mm × 10 mm zinc plate placed in the centre of the patch work, while the other slab having twelve 25 mm × 50 mm × 10 mm zinc plates spread evenly within the patch work. The last RC slab would have twelve 25 mm × 50 mm × 10 mm zinc plates installed within the corroded area surrounding the patch work area. Linear Polarisation Resistance and Galvanic Coupling were techniques used to measure the magnitude of microcell and macrocell corrosion current density, respectively. It was found out that patch repair mix applied to RC slabs lowers corrosion potential value. Subsequently, the corrosion potential difference between steel reinforcement outside and within the patch area increases and thus induces an additional macrocell corrosion. Furthermore, the highest amount of macrocell corrosion can be encountered at steel segments near the patch repair area. Compared with each sample, it was discovered that zinc sacrificial anodes installed within areas with high level of chloride contamination provided the best protection for the steel reinforcement against corrosion damage.
author2 Tan Kang Hai
author_facet Tan Kang Hai
Christian, Alvin
format Final Year Project
author Christian, Alvin
author_sort Christian, Alvin
title Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
title_short Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
title_full Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
title_fullStr Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
title_full_unstemmed Patch repair technology with sacrificial zinc anodes in RC slabs with corroded steel bars
title_sort patch repair technology with sacrificial zinc anodes in rc slabs with corroded steel bars
publisher Nanyang Technological University
publishDate 2023
url https://hdl.handle.net/10356/168308
_version_ 1772829124848517120