How Does Concrete Cancer Occur?

Concrete cancer occurs when moisture and salts, such as in coastal areas, penetrate poor-quality concrete and reach the steel reinforcement bars, causing them to rust and expand. This expansion creates internal pressure, leading to cracks, flaking, and eventual structural damage to the concrete, a process often exacerbated by poor waterproofing, insufficient concrete cover over the rebar, or poor initial construction.

What Factors Can Contribute To Concrete Cancer?

Penetration of Corrosive Agents:
Water, oxygen, and salts (especially chlorides from coastal air) seep into and through the concrete through cracks, poor waterproofing, or low-quality concrete. 

Steel Corrosion:
These agents reach the embedded steel reinforcement bars, causing them to rust. 

Expansion and Cracking:
Rust occupies more volume than the original steel, expanding and exerting immense pressure on the surrounding concrete. This pressure fractures and cracks the concrete. 

Spalling and Disintegration:
The cracking weakens the concrete, leading to “spalling,” where pieces of the concrete surface flake off. 

Accelerated Deterioration:
The newly formed cracks allow more water and contaminants to penetrate further, accelerating the corrosion of the steel and continuing the cycle of damage.