Some Concrete Repair

Concrete repair is interesting. I have seen it done correctly and incorrectly and the ones that typically make the most mistakes repairing it are the ones that place the concrete. They do not make the mistakes because they are bad with concrete. They make the mistakes because they are good with concrete. Many of the repair mortars do not require much work. They do involve a little reading of the data sheets. It used to be that most concrete repair mortar required a bonding agent to be painted on the surface prior to the mortar being applied. Now many just require water, but they do require proper preparation of the surface and they want the surface to be SSD, Saturated Surface-Dry. The concrete needs to be soaking wet but no standing water. Many of the manufacturers' products say keep the substrate wet for 24 hours. This is done because the concrete sucks the moisture out of the repair mortar which creates a weak bond. Some still call for a bonding agent but you need to pay attention to the product itself and see what the data sheet says to do. The data sheets state the proper mixing instructions and the physical properties. The manufacturer's expect you to know what they mean when they state SSD. I have also noticed that when the concrete finishers work with the repair products they make the mistake of overworking the product. The finishers want to keep pushing it down to make a tighter surface and when they overwork the products they actually can make it weaker at the surface. So, in the instance of an SSD application, if they put too little water down and over work the surface, they then end up with a product that is bound to fail.

The ICRI, International Concrete Repair Institute has a list of terms that can be downloaded for reference. The link is below.

http://www.icri.org/GENERAL/ConcreteRepairTerminology.pdf

Their website is

http://www.icri.org/