Concrete is an extremely durable material, but it’s not entirely invulnerable to damage. Once damage occurs, obviously, it has to be evaluated and then repaired. Repairs are often minor, but can sometimes be more extensive and may require the installation of a concrete overlay to adequately deal with the damage.
The most common type of damage to concrete is cracking. Not all cracks are created equal – there are different kinds of cracking, including:
Crosswise or slanting cracks: This type of cracking can be due to the concrete contracting with heat and cold, poor joint placement, or shrinking during the drying process.
Diagonal or random cracks: These cracks are due to plastic shrinkage as a result of too much evaporation after the concrete has been poured.
Reinforcement corrosion: These are cracks that occur above the reinforcement. The cause is improper pouring depth.
Cracks in line with or above reinforcement: This type of cracking usually happens when too much water has been used in the mix. It can also be attributed to caving in around the rebar.
Concrete damage can also occur as the result of creep – this is a problem when the concrete has been under continuous heavy loads. Even something as strong as concrete can bend under constant pressure, and when this happens, the points that are taking the heaviest loads can begin to crack. Creep can also happen when the soil underneath the concrete can no longer support the weight.
When concrete is continuously subjected to compression, tension, bending or twisting, it can end up developing fatigue. This can happen often in places like Minnesota. Large and small cracks will begin to appear. Fatigue can be difficult to diagnose, and may require the assistance of an engineer.
Scaling is another common problem with concrete. With scaling, small areas can begin to flake off the surface. Scaling has a number of causes, including repeated freezing and thawing, over-finishing, improper curing, finishing before the bleed water is gone, use of de-icing salts, or poor draining. The problem has to be corrected, or the small patches will get bigger.
In the hands of a professional, concrete repair is a highly desirable and cost-effective alternative to complete replacement. Depending on the type of damage, various techniques can be used, ranging from simple patching to installing concrete overlays. Replacement is hardly ever the best option, since even with brand new concrete; you can expect to develop issues that will require maintenance, likely within a few years.