Extending the Life of Reinforced Concrete Structures
Corrosion of embedded reinforcement remains one of the leading causes of deterioration in reinforced concrete structures across Australia, particularly within marine, coastal, and high-moisture environments. While conventional patch repairs can address visible damage, they do not always stop the underlying electrochemical corrosion process occurring within the surrounding concrete.
Understanding Reinforcement Corrosion
Steel reinforcement within concrete is naturally protected by the highly alkaline environment created by cement hydration. Over time, however, chloride ingress (commonly from marine salts) or carbonation can break down this passive layer, initiating corrosion.
As steel corrodes, it expands significantly in volume, generating internal stresses that lead to:
Concrete cracking
Delamination
Spalling
Structural section loss
Reduced durability and service life
Traditional patch repairs remove damaged concrete and reinstate cover, but they can unintentionally create “incipient anode” or “halo” effects, where corrosion accelerates adjacent to the repaired area due to electrochemical differences between old contaminated concrete and new repair mortar.
What is Cathodic Protection?
Cathodic protection is an electrochemical corrosion control system designed to stop reinforcing steel from acting as an anode and corroding.
In simple terms, the system introduces a more controlled electrochemical pathway, forcing the reinforcing steel into a cathodic (protected) state.
This can be achieved through:
Galvanic (Sacrificial) Anode Systems
These systems utilise sacrificial metals such as zinc, which preferentially corrode instead of the reinforcing steel.
Typical applications include:
Localized concrete repairs
Patch repair interfaces
Marine and splash-zone environments
Balconies, slabs, beams, and columns
Impressed Current Cathodic Protection (ICCP)
ICCP systems utilise an external power supply connected to inert anodes (commonly titanium-based systems) to deliver a controlled protective current to the reinforcement.
These systems are typically suited to:
Large-scale structures
Severe chloride contamination
Marine infrastructure
Car parks and podium slabs
Bridges and wharves
Long-term asset preservation strategies
Common Cathodic Protection Components
Modern cathodic protection systems utilize a wide range of discrete and distributed anode technologies depending on the structure, exposure conditions, and repair objectives.
Why Cathodic Protection Matters
Cathodic protection is about interrupting the corrosion mechanism itself.
When appropriately designed and installed, CP systems can:
Significantly extend structural service life
Reduce future maintenance cycles
Minimize recurrent patch repairs
Protect surrounding reinforcement beyond local repair zones
Improve lifecycle cost outcomes
Preserve critical and heritage infrastructure
For many structures exposed to chlorides, patch repairs alone can become cyclical. Cathodic protection helps break that cycle.
CARE’s Approach
CARE combines practical remediation capability with engineering-led understanding of corrosion science and concrete pathology.
Our approach may include:
Corrosion diagnostics and condition assessment
Half-cell potential mapping
Chloride and carbonation profiling
Concrete scanning and reinforcement identification
Repair methodology development
Galvanic anode installation
ICCP integration support
Concrete reinstatement and durability repairs
QA inspection and testing
We believe successful remediation requires more than replacing damaged concrete, it requires understanding why deterioration occurred and implementing systems capable of improving long-term durability performance.
As Australian infrastructure continues to age, cathodic protection will play an increasingly important role in sustainable asset preservation and concrete rehabilitation.