Before you can repair concrete, you have to know what caused the problem in the first place. Here is advice on troubleshooting the damage and coming up with the best concrete repair solution.
Concrete surfaces are constantly under attack by
the elements resulting in the need for repairs.
When I was in college I had a job doing maintenance in a downtown Denver hotel. I didn’t really know what I was doing but most things weren’t that hard to figure out. One time, though, I needed to repair a broken up concrete door threshold. I removed the old concrete and went down to the hardware store and bought a bag of premixed concrete. I added the amount of water the bag said to use (maybe just a little extra for good luck) and poured it in and troweled it off-another job well done!
But no! Two weeks later my boss called me into his office. Seems he had just gone past my repair work and found it as cracked up as the original threshold. I was so disappointed! We went back to the scene of the crime to do some actual investigation in advance of launching off on another repair attempt. While we were standing there, one of the kitchen workers came through with a heavy hard-wheeled dolly loaded with supplies that dropped onto the threshold as he passed: we knew the cause of the problem. For the next repair, we added reinforcing steel, used higher strength concrete, and eliminated the drop-off onto the threshold. When I left a year later, the new threshold was still working well.
I took away a good lesson-one that I soon found applied to just about any repair work. Before you can repair anything you have to know what caused the problem in the first place and you have to understand how it is supposed to work. Only then can you make an intelligent decision on how to do the repair.
With any concrete repair, take that lesson to heart and you’re off to a great start. First figure out what caused the damage, do the necessary preparation of removing any unsound concrete and contamination, then install a repair designed to solve the problem. The worst thing you can do is make a repair that doesn’t last. Someone once told me that over 50% of concrete repairs fail again within two years. That is not a track record that inspires confidence.
So let’s start by evaluating the problem and then we can decide how we are going to make a durable repair. This article is only a very superficial treatment of this subject. For more details, the best source is either the International Concrete Repair Institute or the American Concrete Institute. ICRI, in conjunction with ACI, publishes the Concrete Repair Manual which is over 2000 pages long.