Placement of No-Fines Concrete Under Water

[MTNClimber]

Does anyone have experience with no-fines concrete when tremie placed underwater? We have a situation where the owner (the State) would like to fill the void between a new bulkhead and an old bulkhead with concrete. We are worried about large differential water levels if the void was filled with traditional concrete. Are there issues with maintaining the drainage function of the no-fines concrete when tremie placed under water?

 

[Ron]

One of the reasons that conventional concrete can be placed under water is that its grading makes it cohesive. With no fines concrete, you lose that capability and the cement drifts off into the water, significantly lowering the strength and effectiveness of the cement adhesion to coarse aggregate.

 

[MTNClimber]

I probably can live with that as long as it’s still permeable. We usually just fill between the bulkheads with crushed stone but the State is requiring concrete for some odd reason.

 

[dik]

You might be in 'troubled waters' having a permeable concrete under tremmie... the two are not compatible, to my knowledge... best to have concrete walls with 'holes' and a filter fabric with a clean granular material.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SwinnyGG]

probably can live with that as long as it’s still permeable. We usually just fill between the bulkheads with crushed stone but the State is requiring concrete for some odd reason.

Well if you place no-fines concrete under water you're basically just placing a more expensive version of crushed stone anyway.

I'd make sure there isn't some type of load test or inspection after placement, since what you place in this scenario isn't going to behave much different than crushed stone (ie you're not going to get the structural performance of concrete)

 

[dik]

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[MTNClimber]

Well if you place no-fines concrete under water you're basically just placing a more expensive version of crushed stone anyway.

I'd make sure there isn't some type of load test or inspection after placement, since what you place in this scenario isn't going to behave much different than crushed stone (ie you're not going to get the structural performance of concrete)

Haha yeah, I fully understand what I was saying. Sounds like the folks requiring this are inexperienced with SSP bulkheads. We hope to educate them before they piss my tax dollars down the drain.

There won't be any load test. It is simply a void filling application and is not structural. I'm just looking to find a loophole in case they further dig the heals in on using concrete.

 

[cvg]

i would say you will retain permeability.
however, gravel easily flows into all the nooks and crannys and will adjust if there is any future settlement or movement of the subgrade or the old bulkhead. weak concrete wont do that

 

[dik]

what concrete... you need cement.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik