Spalling concrete can be a major problem, but it doesn't have to be. If your concrete has already succumbed to spalling, there are a few repair options available. The type of repair and the work involved depends on the location of the spalling, how deep it is, whether it is on a vertical or horizontal surface, and whether there is any exposed rebar. To start, you can apply a waterproofing membrane to prevent further spalling.
After that, patching can be used for random or localized damage. You can also buy products that apply a very thin layer to the concrete. Large ready-mixed concrete bag manufacturers make them, as do other specialized companies. These products work, but be aware of their limitations.
A wise old concrete mason once taught me an important step: applying a very thin coat of cement paint to the old concrete before applying stucco. Polymer modified cement patches are a good choice for areas with deep pitting, broken concrete lips and edges, deep holes, and other areas where the repair may need to be shaped, such as the edge of a concrete apron. Remember - if you are going to follow with an epoxy coating or paint, these repaired areas will still need to be prepared by grinding just like the rest of the existing concrete. Concrete resurfacing is another option for repairing and revitalizing concrete surfaces that suffer from staining and light corrosion due to the elements, as well as more structural problems such as spalling.
Once all repairs have been made, it's important to protect the garage floor from further pitting or spalling by sealing the floor or applying a coating. The most effective way to prevent concrete spalling is to use a waterproof sealant to prevent water from entering where it can cause damage. If you have spalling on a basement wall or other vertical concrete surface, the solution can be a little tricky. What happens is that water settles on the garage floor and works its way into the capillaries of the concrete.
Corroded steel can expand up to ten times its original volume, putting stress on the surrounding concrete. To fix this issue, first cut away the concrete around the spalled area. In order for the stucco to permanently adhere to the spalled concrete, all loose concrete must be removed and the old concrete must be clean and sound. Repairing a pitted or spalled garage floor is only intimidating because most people don't know what to use or how to get started. To ensure no recurrence of spalling, you should seal your concrete rejuvenation product.
Finally, remember that cold winter weather can cause spalling due to freeze-thaw cycles.