Deficient Clear Cover Repair Method

[Benk713]

I'm working on a project with a very large reinforced concrete footing. The minimum clear cover on top of the foundation was specified to be 2 inches, but in some areas of the foundation the contractor placed the concrete unevenly and only achieved as little as 1 inch of clear cover. The footing is sloped in some portions and roughly 360 cubic yards in concrete volume. The foundation will experience tension in both the top and bottom faces at different times in it's life. As I said, only a portion of the foundation has deficient clear cover. What is the best way to fix/repair the deficient clear cover?

 

[ron9876]

What drives the requirement for 2" clearance?

 

[Benk713]

ACI 318 section 7.7.1 specifies a minimum clear cover of 2 inches for concrete exposed to earth or weather for bar sizes 6 through 18.

 

[Michel60]

Good morning Benk,

The ACI provision allows for "other" considerations when the minimum cover isn't achieved. I don't recall if it's in the Commentary or in another Manual of Concrete Practice section, but you can use a separately applied waterproofing material as an equivalent to concrete cover. Hopefully it's the top of footing that needs added protection.

regards,
Michel

 

[Benk713]

Yes, it's the top cover. Is there a waterproofing material that anyone is familiar with that might work for below-grade concrete protection?

 

[Michel60]

I don't have a specific product in mind but qualitatively you'd like something that has some flexural and crack bridging properties. Possibly a fluid applied material with a cap sheet and protection board?

regards,
Michel

 

[Benk713]

I came across this product in my research and I think it should do the job.

http://kemper-system.com/US/eng/systems/kemperol-waterproofing/

Thank you for pointing me in the right direction. For some reason I forgot to read the commentary of the minimum clear cover section in ACI. That got me going in the right direction.

Ben