If you want a job for life, it could be painting the Sydney Harbor Bridge; once you’re done, you’ll probably have to start at the other end again. The paint continues to prevent the steel from corroding, and corrosion of the steel is what causes rotting of the concrete, also called concrete cancer or spalling.
How does concrete ‘rot’?
Concrete is used in most commercial and residential buildings in a number of applications such as slabs, stairs, posts and columns, support beams, balconies and verandas, walls, pathways, and swimming pools. Large volumes of concrete are involved in structures such as bridges, piers, and high-rise towers. Concrete is generally reinforced with steel bars or mesh, and in larger developments, significant amounts of steel are required for added strength.
The enemies of reinforced concrete are water and air. If these elements gain access to the steel encased within the concrete, it can corrode – the steel expands as it decomposes and fractures the surrounding concrete. As the concrete cracks and crumbles, there is an even greater opportunity for water and air to come into contact with the reinforcing steel and the process intensifies. There are obvious safety concerns as the structural integrity of concrete is reduced.
How to identify rot in concrete
It may be happening without being seen within the concrete, but as it continues it becomes more apparent. You may notice rust marks running through the concrete or the concrete is chipping, cracking, or crumbling. In extreme cases, large sections of the concrete will break off, exposing the rusted reinforcing steel. Reconstructive treatment can involve substantial and costly corrective measures.
A professional building inspection can identify the problem or warn of possible future problems. It can be water accumulated somewhere, small cracks in the concrete or rebar too close to the surface of the concrete. Certainly, it is better to be safe than sorry with concrete rot; It may simply be a matter of improving drainage, painting a surface, or sealing cracks with some type of epoxy mortar or filler. If you have any concerns about concrete rot, it is worth seeking expert advice.
I like to be by the sea
Well yes, most of us do, but this is where concrete rot can be even more prevalent, as chlorides in moist, salty air react more aggressively with reinforcing steel. Concrete rot is an ever-present problem in places near the sea and homeowners must constantly be on the lookout for any signs of deterioration and ensure that protective measures are maintained.
The same can be said for the chlorides associated with chlorine in swimming pools or saltwater pools.
In addition, there is often moisture near the ground surface in beachfront blocks and the water can absorb the structure. Large buildings with basements or underground parking garages can experience the same problem with groundwater seepage.
In short, concrete rot is a common problem. It can cause major structural damage that can be difficult and expensive to repair. It’s not always easy to spot, it can have serious safety implications, and it can be avoided by getting expert advice and using the right materials and proper construction guidelines.