In the UAE and in the region in general, the geology of our coastal cities in the Middle East require the use of pile or raft slab foundations built from reinforced concrete to be used. These very large underground structures are typically constructed in the water table. Waterproofing attempts typically fail to stop all water ingress, and the basements are often times leaky and inundated with groundwater or significant leaks. Sometimes I have seen entire basements flooded almost to the ceiling of the basement.
The question we should be asking ourselves is, once the leaks are plugged and the water pumped out, do we still have a problem or are we in the clear?
Do we still have a problem or are we in the clear?
To be sure this is not a one liner. Let’s consider the situation. The floor is made from reinforced concrete. It is now fully laden with chlorides, even after removing all the offending water...
We certainly can’t see the chlorides, but they are there – unless you have somehow managed to miraculously to suction out the chlorides from within the concrete matrix.
With the chlorides present in party like quantities, you now have the main recipe for corrosion;
Salt
Water (moisture in the concrete)
Oxygen
Unfortunately for corrosion engineers, and fortunately for owners, the initiation of corrosion is not something that you can see. If the waterproofing fails…poof….and there is a leak
If corrosion begins….there is only silence. You won’t hear anything, you won’t see anything, at least not until it is too late.
So while the owner goes about renting out his building and counting his rental income, the corrosion reaction also goes about eating away at his steel foundation.
What are the owner’s options?
There are a plethora of remedies available. All claim to stop this phenomenon in some way or form. But to be honest there is only one method, which will in effect freeze the corrosion in its tracks. Cathodic Protection. In the next part of this blog, we discuss in more detail the corrosion problem, cathodic protection and sustainability.