Concrete cancer is a serious problem that, if left undiagnosed and untreated, can affect the structural integrity of a building. It is caused by the oxidation of the embedded steel structure as a result of water penetration and can lead to the concrete fracturing and chipping. In order to prevent and treat concrete cancer, it is important to understand the causes and remedies. The most common cause of concrete cancer is water penetration.
When water penetrates concrete through fine cracks or eroded porous surfaces, the structural steel within which it expands oxidizes. This expansion creates more concrete cracks, allowing for greater water penetration, the spread of cancer, and ultimately chipping (when concrete starts to fall out of a building). In order to repair concrete cancer, it is important to remove damaged concrete, clean and replace oxidized and exposed steel, and fill in cracks. This process usually begins with the removal of concrete contaminated with chlorides.
There are many ways to do this, but the most common include waterblasting or using electric hammers, chisels, concrete saws and other similar tools. After removing chloride, the reinforcing bar is made resistant to corrosion by applying protective coatings. To strengthen protection against chloride contamination, a surface treatment in the form of a cathodic system is applied. For situations where concrete carbonation and low concrete coverage are the problem, the engineer might recommend the use of a polymer-modified repair system. This option removes the concrete around the rebar and cleans the steel, before applying both the steel primer and a polymer-modified material.
They can also apply a protective anti-carbonation layer to the entire surface of the concrete. Sometimes experts may recommend the use of additional reinforcing steel anodes before applying new concrete, or the steel could be replaced in severe cases. Chemical water repellency can be added to the concrete surface itself by applying Resistain, a waterproofing sealant for concrete. Remedies may include site-specific electrochemical treatment for near-ocean properties, or simply removing damaged concrete, cleaning or removing affected steel, and replacing with new material. An anti-carbonation coating or other specialized coating can be applied to strengthen and preserve the concrete. Whether it's detecting a long-standing water ingress problem, treating the resulting concrete cancer, or waterproofing balconies, or installing preventive maintenance of protective coatings, Conspar can help. Over time, small initial areas of particular cancer become larger and more costly to repair. In our experience, this equates to damage growth of approximately 5% per year, which directly affects repair costs.
As demonstrated by these rates, concrete cancer repair and prevention is of paramount importance to homeowners in terms of maintaining the value of their asset and avoiding high repair costs in the future. Fracture in concrete leading edges, ceilings, beams, and columns is most commonly due to the onset and development of concrete cancer. These areas may have visible rust spots on the surface, localized fractures, and a “bubbling” sound when struck with a hammer. These require a complete rupture to reveal clean steel, remove rust from all steel surfaces, and restore concrete to paintable finishes using specifically designed structural patch materials. The methodology used by Conspar since 1996 is verified and recommended by structural engineers and is fully detailed in our “Site Specific Specifications (SSS)”. Repair and rectify all areas of specific cancer as detailed in the “Site-Specific Scope of Work (SSW)” compiled after a site visit.
The corresponding repair methodology specified in the designated material product data sheet is then applied. Other common areas of water-driven concrete cancer include basements, underground parking lots, flat concrete roofs, and balconies. Consider high-quality waterproofing options such as Wolfin or Cosmofin waterproofing membranes to seal new horizontal concrete surfaces. Stratum properties across Australia face significant repair costs and life-threatening damage from concrete cancer.
Common signs include cracking, crumbling or flaking of concrete; rust spots or bubbles on concrete or cement plaster; and leaks in ceilings and walls. Water penetration causes reinforcing steel to rust which expands with rust causing more cracks and chips in the concrete. Concrete is porous absorbing acid created during chipping process accelerating corrosion exposing internal steel structure to air & water. Repairing & filling small cracks will help stop spread of concrete cancer, but key to successful remedy is timely & professional identification & treatment.
Water is likely to eventually penetrate inner steel & concrete cancer will occur over time.
Concrete cancer
can be a serious & costly problem if left untreated misdiagnosed or given an irreparable remedy. Regardless whether damage is severe or moderate waterproofing & integral sealing after repair are important to minimize risk of concrete cancer. It's a good idea to regularly look for telltale signs so that it can be remedied before it worsens & becomes serious problem & begins to affect strength & structural integrity of building. If there are voids on surface they need to be repaired so that concrete surface does not crack before applying Resistain.Concrete cancer
, if left undiagnosed & untreated can affect structural integrity of building but with timely & professional identification & treatment it can be prevented & treated successfully..
