Pouring concrete under water

[GPintheMitten]

Put a 2x4 in the hole and wait til it freezes and then pull the Popsicle out.

 

[GreenYellow]

I used to work for a billboard company. I've seen it done several times... Just pour the properly mixed concrete in. Don't overthink it.

 

[texas42]

The idea behind the tremie method is you are displacing the water by adding the concrete to the bottom of the hole thru the pipe. That way the water can not dilute the concrete that much. You must keep the tremie pipe in the concrete. Don't pull it up out of the concrete till you have the hole filled. You can ease it up as you add concrete just don't pull the very end out of the concrete. This method is commonly done on casions only much bigger scale.

 

[4570Man]

Put a 2x4 in the hole and wait til it freezes and then pull the Popsicle out.

Around here you would be waiting a LONG time for that to freeze. Even if it did free it would be equally as hard as a hole full of concrete to pull out. Even if it did work now he is pouring concrete below freezing which is bad.

 

[GPintheMitten]

Around here you would be waiting a LONG time for that to freeze. Even if it did free it would be equally as hard as a hole full of concrete to pull out. Even if it did work now he is pouring concrete below freezing which is bad.

Yah, I know. I was just kidding. I already offered a few ideas on real solutions so I thought I would add a silly one.

 

[papa4fofox]

Typical in tremie concrete pours using a longer pipe is to put an inflatable ball in the tremie pipe before concrete is added. This ball provides a separation between the water in the pipe and the concrete. The weight of concrete pushes the ball down the pipe forcing the water ahead of it. When the ball pops out you know the concrete is flowing and as long as you keep the end of the pipe in the concrete there will not be any washout of the cement in the concrete.

 

[jaotguy]

or . if you really want to keep them separate , line the hole with a cheap plastic sheet. keep the sides of the plastic higher than the hole , pour the concrete onto the plastic and it will sink to the bottom , continue pouring along the hole till the water rises and runs out , replaced by concrete . ... flip the rest of the plastic over the top to cover the fresh concrete against any further water ....

 

[timster2]

Just thinking outside the box, How about taking a large heavyweight trash bag put it over the hole and fill the bag displacing the water as it fills. No problem with the mix, concrete is heaver than the water so it should displace and sink as the bag fills. A little help from a tamper and your done.

 

[Red Horse]

You need to use a method called "tremie"
The tremie concrete placement method uses a pipe, through which concrete is placed below water level. The lower end of the pipe is kept immersed in fresh concrete so that the rising concrete from the bottom displaces the water without washing out the cement content.
You can do a search and get a good idea how to do it

Texas 42 is right on-only way to do it-get a piece of 4" pvc, big funnel on top, run pipe to bottom and start pouring!

 

[PILOON]

I have done it making piers for clients to anchor docks.
Some dilution will want to take place so I have used thin plastic bags and pour into the bag which holds it together with minimal dilution.
The bag follows the lake bottom contours to make a perfect fit.
Stuffing gaps with old insulation wool also helped.
For posts I simply pour the concrete which displaces any water.
Actually the constant presence of water makes for a much harder concrete.
Note that on hot days contractors usually spray the concrete and often cover with burlap and sometimes straw to retain moisture.
AS said, concrete is a chemical reaction and not a drying one.

Reason for bagging is to not get over dilution which does make for a weaker mix.