Concrete cancer, also known as concrete chipping, is a serious problem that can cause structural damage to buildings. It occurs when steel reinforcement inside a concrete slab begins to rust and expand, displacing the surrounding concrete and causing it to become brittle and crack. There are several external factors that can contribute to concrete cancer, such as chloride corrosion in salt water or extreme weather conditions. Flat roofs are particularly prone to this problem.
Additionally, improper construction techniques can lead to steel expanding and deforming, resulting in concrete parts falling off. This is known as “spalling” and increases the exposure of the steel, compounding the problem. The initial stage of concrete cancer is caused by the alkaline nature of freshly poured concrete being reduced through the ingress of water. This process weakens the steel bars that resist tensile forces in concrete, reducing their effective cross-sectional area until they can no longer withstand the load they have to bear.
At this point, the slab or other structure is at risk of suddenly failing or collapsing. The best way to prevent concrete cancer is through waterproofing. Invest in good quality waterproofing membranes to help minimize the chances of water leaks. Common signs of concrete cancer include cracking, crumbling, or flaking of concrete, rust spots or bubbles on concrete or cement plaster, and leaks in the ceiling and walls.
If you suspect you have a problem with concrete cancer, it's important to seek professional help from a reputable company like Freyssinet who have experience treating it. They will be able to assess the damage and provide you with a quote for repairs. Remedies for concrete cancer may include electrochemical treatment for properties near the ocean, or simply removing damaged concrete, cleaning or removing affected steel, and replacing with new material. An anti-carbonation sealant is usually also placed over the entire surface of the concrete to reinforce its strength.
Concrete cancer is a serious problem that can cause structural damage to buildings if left untreated. Investing in good quality waterproofing membranes is the best way to prevent it from occurring in the first place. If you suspect you have a problem with concrete cancer, it's important to seek professional help from a reputable company who have experience treating it.