For residents of coastal areas, concrete cancer has become a popular term, and is no longer just reserved for the building industry due to its emergence in residential buildings. As the name suggests, concrete cancer affects concrete much like a disease. It removes the structural fortitude of concrete, being one of its primary benefits in building. Removing this strength, can make structures weak and prone to collapse, this makes it quite the headache for building owners and managers.
Concrete cancer or concrete spalling as it is also known, benefits from being diagnosed and treated early, although in its nature, it may return, and the costs and affects can be catastrophic for commercial or residential structures. This ‘disease’ of sorts is created by the steel that is within concrete, not the actual concrete.
Steel acts as a foundation, providing reinforcement which gives additional strength to structures. This steel, despite being encased can rust and degrade. This is because concrete is permeable which means moisture can actually enter the concrete, which, when combined with the natural airborne salts associated with coastal areas, can provide a recipe for disaster. These salts will create the perfect environment for rust and decay of the steel.
This ‘rusting’ then results in steel changing in shape and size, which means the surrounding concrete can crack – typically one of the first symptoms of concrete spalling. As the issue progresses, more cracks and openings can exacerbate the problem. The previously robust supporting steel is no longer able to resist force and the overall structure can be exposed to complete structural failure.
The question then comes up – well why use concrete at all in coastal areas? Well, the strength and durability of concrete is still un-paralleled, and the issue of concrete cancer doesn’t purely lie in the material, but in the maintenance and planning of structure due to their location. This failure in design has become more apparent as structures particularly on the Gold Coast and northern New South Wales, due to the coastal conditions. It has been noted that the problem has been escalating in recent years, and many buildings are in various states of decay due to concrete spalling.
The reason for this is contested, and the classic culprits are,
- Insufficient concrete cover
- Waterproofing of concrete is poor
- Excessive weight creating stress fractures
Concrete Cancer is becoming better understood by those in the building industry, as structures built in the 70’s and 80’s have been known to exhibit the consequences of inadequate concreting. This has led to somewhat of a boom in the remedial building industry, and given building mangers more options when it comes to amending the damage. The age of the building is never a complete indicator of its risk, the quality of construction and maintenance of the building are key components.
Builders in areas that are prone to concrete cancer should take additional steps to reduce the risk of it occurring. This can include concrete waterproofing, through a variety of ways. This practice and preparation is unfortunately too late, and while there are remedies for concrete cancer, it is much easier to have a preventative approach to this disease. The cost and effort associated with removing concrete accurately and unobtrusively and repairing the steel usually in assistance with coatings to further protect the support frame, can be immense.
For large scale projects, including high rises and commercial complexes, the cost associated with going without these buildings can also be substantial. This means that a timely and thorough solution is always desired, although, repairs done half-heartedly, or merely cosmetic fixes, can mean further pain down the line.