Bond breaker for underwater contraction joint

[graybeach]

Hello all,

I'm designing repairs for some large vertical spalls in a dam structure. Typical size is 6 feet wide by 12 feet high by 1 foot deep. The water level fluctuates, and the spalls may be partly underwater during repairs. To save money, I am trying to come up with a way this could be done without a cofferdam.

One possibility might be use forms and preplaced aggregate. The surface prep, forming, and aggregate placement could all be done by divers, and the grout could be injected from the bottom of the form and could displace the water which would exit through a port at the top.

Based on my research, this seems doable except that some sort of bond breaker would be needed for repairs that are adjacent to existing contraction joints. I am trying to find a bond breaker that could be applied/installed underwater and would be remain in place during aggregate placement and grouting. Any ideas?

 

[JedClampett]

How about a sheet of visqueen taped into place?

 

[Prepakt1]

it may be possible to use a metal mesh and a fabriform bag as a form. Just pour concrete normally into the bag. Its an easier method to carry out this type of repair. Works perfectly underwater. If you need a joint use two bags.

Intrusion Prepakt /marineconcrete.com

 

[graybeach]

Ah - tape! I found some butyl tape that can stick underwater and will go with the visqueen and tape.

Cool website Prepakt1. I don't think Bags would work for this though. It's a structural repair with a lot of rebar, and it's partly visible.