Submerged cold joints ( in seawater ) 1

[struct_eeyore]

Hi all,

I'm looking for guidance on mitigating water intrusion into underwater cold joints in a marine environment. This is for a pile repair, where the top section will be chipped away and re-poured, leaving a cold joint ~2-4' underwater. I'm specifying a migrating corrosion inhibitor to be added into the mix, but am also wondering if there is a mechanical solution. I'm not certain a water stop would work well as it would be difficult to get a proper seal in the chipped concrete face. Any suggestions?

 

[r13]

Is the pile compression only? I believe there are quite a few compression/expandable type sealant available on the market. The only statement troubles me is "the top section will be chipped away", exactly how you going to do it, under water with hammer and chisel?
And how is the new concrete to be poured, under water too?

 

[STrctPono]

I would consider a hydrophilic waterstop. Not sure what you mean by "difficult to get a proper seal in the chipped concrete face." Adeka makes hydrophilic waterstops that come in a caulking gun that would conform nicely to a "chipped" concrete surface. You just need to make sure you don't put the waterstop too close to the edge. For this reason, you typically need more cover over the reinforcing steel.

The corrosion inhibitor is good! I would recommend an amine carboxylate migrating corrosion inhibitor. Check out MCI. In my opinion, better than just dosing with 5 gallons of Calcium Nitrite. I would also recommend considering adding a crystalline waterproofing to the concrete mix. Look up Xypex or KIM. It's very expensive, but the theory is that the crystals grow across cold joints and create a barrier that waterproofs it. I use it on all salt water pier projects.

If you want to get really crazy, you could put something like Simpson's FX70 fiberglass jacket with epoxy grout around the pile to bridge the construction joint. That would seal it for sure.

Also, I'm assuming you will be adding a VMA to the new concrete mix since you will be pouring underwater?

 

[struct_eeyore]

@STrctPono - MVP!

 

[STrctPono]

Sorry. Don't want to give you bad information. It actually wasn't an Adeka product as this cannot be applied underwater. It was either a DeNeef or Euclid/Tamms hydrophilic product. I'll check tomorrow when I get to the office.

EDIT: I checked and the recommendation was to saturate an open cell backer rod with either CFL Pure or CUT Pure. You should contact DeNeef, however, to discuss the specifics of the application as your application is tricky with having to place the material, then forms, then concrete. There will be a lot of time that the waterproofing material will be underwater prior to placement of concrete. I will retract my earlier comment.