Concrete cancer and pipe repair: Understanding the link

Concrete cancer can cause serious structural damage to buildings and structures
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Concrete cancer is a common problem. Until you experience it first hand, you might know what it is. But once you become aware of it, you will start seeing it everywhere.

It is easy to spot. Concrete buildings, walls, fence posts… any concrete structure which has been reinforced with steel and has chunks missing from it is suffering from concrete cancer.

At first, concrete cancer is merely unsightly. Visible damage is not nice to look at it. Left untreated however and it can cause serious degradation, surface damage, structural damage and ultimately the collapse of the concrete.

Although concrete has been around for thousands of years, concrete cancer has only become a problem since steel was introduced to the mix.

As such, the construction indsutry is learning about concrete cancer all the time. We are discovering what causes it and how it can be prevented. There is a role for pipe repair in that.

What is concrete cancer?

Concrete cancer occurs in concrete structures which have been reinforced with steel. In terms of the history of concrete, reinforcement is a fairly new development.

The first building to be built in Europe from reinforced concrete was the famous Weaver’s Mill in Swansea, opened in August 1898.

When constructed, it was billed as a building so strong it could never be destroyed. It survived two World War II bombings in 1941. When it was eventually demolished in 1984 as part of a regeneration project, it took a considerable amount of effort to raze it to the ground.

That was the point of reinforcing concrete with steel. It was done to create a super-strength material which could withstand almost anything. At the same time, steel combats the negative impacts of the expansion and contraction of concrete. It prevents cracking.

There was however a side effect of reinforcing concrete with steel which nobody thought to consider. What would happen if moisture and oxygen penetrated the concrete and the steel inside began to rust? The answer to that was the problem we now know as concrete cancer.

How does concrete cancer occur?

Concrete cancer happens when the steel reinforcement starts to corrode. As it does so, it expands. This causes the concrete surrounding the steel to crack, starting off a vicious circle.

Once the concrete has cracked, more moisture and oxygen gets in to react with the steel. The process of corrosion quickens, eventually leading to the disintegration of the concrete and significant structural damage.

Concrete cancer is not just restricted to buildings. North America in the 1970s began installing thousands of kilometres of prestressed concrete cylinder pipe (PCCP) for high capacity, high pressure water networks running beneath towns and cities.

A concrete pipe with high tensile steel wires carrying water. You probably do not need telling how that has gone, right?

In the United States alone, nationwide repairs and reinforcements of PCCP pipelines could cost more than $40 billion according to a technical assessment carried out by the U.S. Environmental Protection Agency and the American Water Works Association.

How can concrete cancer be avoided?

The easiest way to avoid concrete cancer is in the construction stage via strict regulations governing the composition of steel reinforced concrete.

That was the lesson pipeline and water industries took from the 1970s. Safety standards had been diluted and lowered from when PCCP first burst onto the scene as a pipe material in the 1940s.

Changes to the structural design of PCCP in an attempt to save costs resulted in the raft of pipeline failures across the US.

Weaver’s Mill in contrast was still standing tall and almost indestructible 95 years after it opened because it had been built with the right balance between steel and concrete to prevent concrete cancer. Those Victorians knew what they were doing.

But what if you live or work in a building constructed with reinforced concrete? How can you prevent concrete cancer becoming a problem?

Waterproofing is perhaps the best way. If you can prevent moisture getting into steel reinforced concrete, then you lessen the chances of corrosion taking place.

Cracks should also be attended to as a matter of urgency. One method of concrete cancer repair and prevention is to fill cracks and holes in reinforced concrete with an epoxy putty.

Different putties have different formulations. Filling gaps and cracks in reinforced concrete using an epoxy putty with high corrosion resistance like Sylmasta AB Original will better protect the steel.

Concrete cancer and pipe repair

Which brings us nicely onto concrete cancer and pipe repair. If moisture is the main cause of concrete cancer, then clearly a burst or leaking pipe near reinforced concrete is bad news.

To make matters worse, drinking water is chlorinated. Those studying concrete cancer have recently concluded that even low levels of chlorine can have an impact.

Chloride ions and other chloride-based compounds found in chlorine react with the calcium in the concrete, turning it into calcium carbonate.

This lowers the pH level of the concrete to the point where it will begin to attack the steel, causing it to corrode. Drinking water effectively turns concrete against the steel inside it.

Carbon dioxide has the same impact on concrete. There is a theory as a result that global warming and increased levels of CO2 have made concrete cancer more prevalent over the past 30 years.

Whilst it will take global action on climate change to reduce carbon dioxide levels, preventing concrete cancer through quick and easy pipe repair is a much more achievable goal.

It is vital to act rapidly when you notice a burst or leaking pipe. The sooner it is repaired, the less chlorinated water can escape and potentially come into contact with reinforced concrete.

Your first port of call might be a plumber. If they can fix the leak as a matter of urgency, then great. But what if they cannot attend the problem for several days? Or what if you cannot afford to hire a specialist?

This is where a pipe repair kit comes in. A pipe repair kit contains all the products for fixing a live leak in under 30 minutes without the need for any formal training and at a cost of under £20 for a small domestic line.

And that is the link between pipe repair and concrete cancer. Fast response to the former can help prevent the latter.

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