by Mike Sheehan
Scaling or Flaking Concrete is a problem Ready Mix Concrete Producers receive complaints about, especially after concrete is exposed to its first winter. There are several reasons this occurs:
- Ordering too weak of a mix (4000# is recommended)
- Failure to let bleed water leave the surface, and re-incorporating it into the thin top layer, which weakens the paste.
- “Blessing the surface” with hose water during hot weather while finishing, again weakening the paste.
- Too little Air Entrainment in the mix. Air Entrainment creates millions of tiny voids which allows water to expand and contract in the winter months, without breaking up the concrete mix.
- Using De-Icers during the first year of the concretes life.
These are some of the common causes, which can easily be prevented. Like any subject matter, the more we learn and share with others, the better we become.
Scaled concrete can be repaired, however, it may not match the original placement, but it will correct the problem from further deterioration. The surface must be clean and free of all loose material, and then there are several applications that can be used. Mortar Mixes, Latex and Polymer are a few options.
To read more about this topic in detail, visit www.nrmca.org and look for CIP 2