Unfilled grout pockets exposed to winter conditions
Unfilled grout pockets exposed to winter conditions
(OP)
We are in the middle of a project where there are large concrete column bases with large grout pockets for shear keys. Due to unforeseen circumstances we have to shut down construction until next spring. Our winters usually are cold and snowy mingled with temperatures that rise above freezing intermittently. My boss is worried that if we leave the grout pockets exposed to the elements (not covered or sealed) that water will accumulate in the grout pockets and break the concrete as it freezes. He wants to seal them up. I think that won't happen because they aren't sealed at the top and any expansion of the freezing water will just push the ice out the top of the pocket. I think if we don't get them sealed right water will get in there and by putting a lid on the space, we will create the problem my boss is worried about. What do you think? Will it be an issue to leave them open, or do we need to seal them closed?






RE: Unfilled grout pockets exposed to winter conditions
Unless your pockets are close to edges, I doubt that you'd have problems leaving them exposed. I don't know how to quantify that however. You could grout the pockets with a lean mix that could be easily dug out at a later date. I've used this approach to protect exposed rebar.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Unfilled grout pockets exposed to winter conditions
I hadn't thought about using a lean mix to fill the holes. I was thinking of expanding spray foam or something. I'll have to look into that.
RE: Unfilled grout pockets exposed to winter conditions
RE: Unfilled grout pockets exposed to winter conditions
The question is simply how much lateral pressure. One thing that a bottle may have going for it is its limited width. The ice strain that you'd accumulate over, say, the Atlantic ocean would obviously be more than you'd get across the width of a beer bottle.
Google tells me that the maximum compressive strength of ice is about 25 MPa. And your shear keys must be designed for some lateral pressure since they are shear keys. Any chance their strong enough to resist 25 MPa? I guess that your keys may be designed to resist shear in only one direction which may or may not be oriented perpendicular to the concrete edges that concern us here.
kingnero's approach sounds pretty good to me, particularly if you throw a couple of 2x's over the top to keep the styrofoam from floating.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Unfilled grout pockets exposed to winter conditions