A Theoretical Analysis of the Causes, Effects, Repair and Rehabilitation of Concrete Corrosion in Estuarine and Terrestrial Environments

Newberry, Christopher Adam (2008). A Theoretical Analysis of the Causes, Effects, Repair and Rehabilitation of Concrete Corrosion in Estuarine and Terrestrial Environments B.Sc Thesis, School of Engineering, The University of Queensland.

       
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Author Newberry, Christopher Adam
Thesis Title A Theoretical Analysis of the Causes, Effects, Repair and Rehabilitation of Concrete Corrosion in Estuarine and Terrestrial Environments
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2008
Thesis type B.Sc Thesis
Supervisor Hamid Ronagh
Total pages 173
Language eng
Subjects 0905 Civil Engineering
Formatted abstract
A theoretical analysis of the causes, affects, repair and rehabilitation of concrete corrosion in estuarine and terrestrial environments.

Reinforced concrete dates back to the 1860s, although it is arguably the most versatile material used in modern construction. This is primarily due to its low cost, wide availability, formability and excellent structural and durability properties. Corrosion of metals is considered an electrochemical process in which iron (Fe) oxidises in the presences of moisture and oxygen to produce rust (2Fe(OH)2). There exists two main direct causes of steel corrosion within reinforced concrete, namely neutralisation (carbonation) and chloride induced corrosion (chloride attack).

Chlorides reduce the highly alkaline passive layer surrounding concrete reinforcement, which in turn promotes an oxide layer over the steel which results in subsequent corrosion. Similarly, carbonation neutralises the passive layer to approximately pH 8.5 using carbon. The typical methodology for concrete affected by carbonation is usually patch repairing with a suitable anticarbonation coating applied afterwards and realkalisation. If chloride is the cause of corrosion then patching (including overlaying and encasement), cathodic protection and electrochemical chloride extraction are the three most common strategy options.

In this study three previously completed case studies were examined and included a rail bridge and shopping complex in Queensland and a wharf in New Zealand. Results concluded that the reinforcement corrosion of two case studies were as a result of chloride induced corrosion. It was determined that carbonation was the cause of the shopping complex’s corrosion.

It was concluded that the recommended treatments against chloride induced corrosion included a combination of Impressed Current Cathodic Protection (ICCP) and Patch Repair/Protective Coating systems. On the contrary, Electrochemical Realkalisation (ER) and Patch Repair/Protective Coating systems were the chosen options against carbonation.
Keyword Concrete corrosion
Estuarine
Terrestrial

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
 
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Created: Tue, 11 Nov 2014, 15:16:30 EST by Ahmed Taha Siddiqui on behalf of Scholarly Communication and Digitisation Service