Crack Repair in Concrete Filter Bed 1

[JayHatCOB]

We have noticed cracks on both the inside and the outside of our concrete filter bed at our water treatment plant. The filter bed was constructed in 1965(?) and is approximately 20' L x 18.5' W x 13' D.

The crack starts about 5' above the finished floor level, which is just about at the "intersection" of the top of the sand media and the bottom of the anthracite coal media. Water is continuously running out of the crack.

We are scheduled to take the filter bed out of service within the next six months for a regular media change and would like to address the crack issue prior to any media replacement.

At this time, we cannot determine if the cracks goes all of the way through or whether they line up with each other.

Planning for worse case, does anyone have any suggestions as to 1.) what type of structural crack repair material (grout, epoxy, etc.) should be used and 2.) what type of epoxy coating should we consider using on the inside of the filter bed?

Thanks in advance.

 

[JedClampett]

There are two choices for crack repair materials. One is rigid, like an epoxy, the other more flexible, like a hydrophobic polyurethane.
In your case, I would use epoxy injection. It provides a more structural fix, and will slow or stop any additional corrosion in the reinforcing (hopefully there's reinforcing). The hydrophobic materials are messier, need water to activate, and are more susceptable to mechanical wear.
Sika makes good materials and has good customer service. Contact them. They might even be able to recommend some local installers.
As far as coating the filters, why? Unless you're using some corrosive chemical, like ferric, in your process, the concrete should be just fine. Has there been any damage (besides the cracks) the concrete surface over the 45+ years? And coating won't do anything about cracks.