Concrete Cancer and Spalling Repair
Concrete Cancer is often identified by signs such as flaking (concrete spalling), rust stains which seem to leak out from within the concrete, bubbling of concrete render or through leaks in the roof of a structure. As often as not, people mistake these signs as general weathering and delapidation, caused by the elements; but whilst this may have a part in exacerbating the problem, the real problem lies within the concrete itself.
As a general rule, Concrete Cancer is caused when the steel reinforcing within a concrete slab begins to rust. As steel rusts it can expand up to 7 times its original size causing the surrounding concrete to be displaced and flakey. As the steel pushes the concrete away, more water gets to the steel expediting the process.
The process can start in many ways, but generally it is due to one of the following:
- Poorly treated reinforcing steel being used in the original pour of the slab
- The ends of reinforcing being too close to the surface allowing water to seep through concrete and react with the steel
- Incompatible metals being used in close proximity to each other, thus causing a reaction
- Fractures in the concrete allowing water to penetrate the concrete and react with the steel
Spalled concrete is an eye-sore, but more than that it is also a potential OH&S hazard. Overtime, and with increased exposure to the elements, untreated pieces of may fall from heights risking the lives of passers-by below as well as potential damaging property. Spalling and delaminated concrete should be repaired immediately, as deffering the treatment will inevitably lead to increased problems into the future.
Furthermore, any attempts to fix the problem for the short-term (such as rendering over the problem) will only exascerbate the issue. Despite, potentially looking better, the rusting process will continue below the surface causing the steel to again displace the concrete and in some cases rust so badly the steel eventually needs replacement. Treatment and repair of the concrete is the best solution.
Remedial with over 40 years corporate experience in Sydney and Brisbane, have staff whom are trained in the identification of underlying issues and where problems stem from. Once found we will begin the process of concrete spalling repair by removing all drummy concrete, grinding back the reinforcing steel to remove all rust, treating the steel with anti-corrosives and then reinstating the render to restore the original facade.
Where the issue has orignated in the slab on the roof of the building structure, it is likely that waterproofing will need to be undertaken. Once the rusted reinforcing has been treated, application of a waterproofing membrane will help prevent the ingress of moisture to the slab and prolong the life of the steel and therefore teh structure itself.
If you would like any more information on concrete cancer, or would like to arrange someone to help solve your concrete problems, whatever the nature, please contact your closest head office today. Or for more information, please request our latest brochure.
