Treatment of Concrete Cancer

28 September 2020
By Simon

When it comes to building repair, we’ve found there are few issues that can’t be rectified, and this includes concrete cancer. The term concrete cancer is one that sounds pretty insidious, but the truth is, it is. In much the same way that cancer of the body has the ability to spread and cause damage once it is inside, so too does building cancer, which will grow rapidly causing other elements to weaken and erode too.

But what can you do? This article will cover off the importance of identification, the role of treatments and other things you need to know.

Does my building have concrete cancer?

While there are a few overt signs of concrete cancer, sometimes it is so hidden that it can only be confirmed by a licenced structural engineer. That said, let’s assume there are a few worrying signs you have noticed. In this case you may be able to confirm your building has concrete cancer on your own.

When you see any chipping, spalling (meaning the render is coming away), or cracking on the façade, walls, balcony, or any other areas in the building, there may be an issue underneath. Where you can (it is both safe to and it is not going to be overtly obvious or cause any other issues) peel a section away. If you can se rust stains, see that the issue you have uncovered looks bigger than you first thought, or can see the steel itself, it will be a sign of concrete spalling and time for you to engage a professional to identify the cause so you can get to the task of rectifying the issue sooner than later.

Is cracking really a serious structural issue?

Although cracking may seem like a harmless, external issue that can easily be covered by reapplying a fresh layer of concrete, more often than not, it is a result of a severe structural problem.

It is a product of a prolonged corrosion of reinforced steel, which happens when oxygen and moisture seeps through the concrete and react with the iron in the rebar. Yes, you may be wondering, how do oxygen and water droplets penetrate that far? It can either be because of insufficient concrete cover, poor workmanship, machine damage to a wall, or concrete carbonation. The problem is, as the rusting gets worse, the expanding steel pushes the surrounding concrete our, causing more spalling and cracking and ongoing structural degradation.

When left untreated, the structural integrity of the building will suffer which could potentially damage the entire structure and endanger the occupants and the assets as well.

How to treat concrete cancer?

There is no one-size-fits-all solution for concrete cancer but by engaging a professional team (That’s why you are on the Remedial Website after all right?), you can have confidence that the treatment used to rectify the issue will be one that will deliver a long-term solution to concrete cancer.

Let’s take a look at two oft-used and main types of concrete cancer treatment that our specialists at Remedial recommend.

Polymer Modified Repair System

This is a treatment used for concrete cancer caused by either low concrete cover or by concrete carbonation. In this process, all the spalled and cracked concrete is removed to show the steel within, which is then cleaned and freed from corrosion using different techniques.

Once the rebar has been restored to an almost-new state (or is in fact replaced), it is then surrounded with a steel primer and a polymer modified material that will effectively shield it from corrosion. Ideally, it is then encased with concrete cover that’s between 15-78 mm as specified by AS:3600. The surface is then treated with an anti-carbonation protective coating, which acts as a barrier of carbon dioxide.

Special Concrete Repair with Electrochemical Treatment

This solution is best for properties located near water.

Although the process is often more tedious than the previous one, this treatment starts with the removal of chloride-contaminated concrete. There are numerous ways to undertake this but the common ones include water blasting or the usage of power hammers, chisels, concrete saws, and other similar tools.
After the chloride is removed, the rebar is made corrosion-resistant by the application protective coatings. To reinforce the protection from chloride contamination, a surface treatment in the form of cathodic system is applied.

Is concrete cancer repair possible even for severe cases?

It’s easy to isolate a moderate case of concrete cancer and simply replace the area that is problematic but if the issue is a systemic one, a large-scale removal and replacement may need to be done. The challenge exists, however, to determine the ideal solution for the rectification process. If you simply rely on a handy man, you cannot expect a long-term solution, unless that person truly understands how each of the concrete cancer symptoms are connected with other potential structural issues. They may treat the visible signs but fail to fix the cause of the problems. It’s like getting a new veneer for your tooth when what you really need is a root canal.

This is where technology comes in. At Remedial, our expert work with your consulting engineers to help determine the most appropriate and cost-effective methods to rectify concrete cancer and determine what areas need to be fixed.

If you want to learn more about how we treat concrete cancer or find out about preventative measures that we can apply to your structure to help it before it becomes too late, give our offices a call and ask for us to come out and visit you on-site today.