Case 2

Cause of Defects

Corrosion of reinforcements may have taken place causing an expansion in concrete volume. This expansion would causes cracks formation in concrete and hence on the paint work.

Corrosion may be due to (Figure 1a to c):

• Insufficient concrete cover provided [5]
• Improper detailing of reinforcement at design stage[5]
• Improper handling and placement of concrete and reinforcement at construction stage [5]

Wind driven rain may have entered into the cracks and wash out the rust onto the external surface.

The rust might have leached out to stain the wall. The light coloured wall shows off the rust stain marks distinctly.
It is also evident that algae growth is starting to form around the rust stains.

Rust stains decreases the aesthetic value of the wall. However, the source and degree of corrosion must be identified so that its effect on the structural integrity of the building can be assessed.