Cyclopean concrete

[killswitchengage]

Hi
In order for us to fill an excavation that will harbor a foundation for a bridge , cyclopean concrete is to be used followed by the footing it self . The footing is a strip one of course but the excavation has phreatic water in it . So , cyclopean concrete was administered in order to fill the hole . Since i have no knowledge of cyclopean concrete specifications i am turning to you guys for guidlines.

 

[Mad Mike]

Ah, Cyclopean concrete...better known as "plum" concrete in case you've confused anyone!

It's a cost saver- mixing sound rock (boulders) into the concrete to dilute the volumes. I'm not sure of any specifications but one thing to bear in mind is that it's not being used as "structural" concrete...as a foundation improvement system it is unlikely you would need a very high strength mix to safely achieve your design bearing pressure. The rock fragments (boulders) must however be sound rock.

Pouring it directly into water doesn't sound like the best strategy- as a precautionary measure and for the sake of inspecting the excavation base I would always request for the water to be pumped out prior to pouring. Could depend on your soil/rock profile though.

All the best,
Mike

 

[killswitchengage]

"Could depend on your soil/rock profile though"

Emm i am not sure maybe we are talking about silty sands i would guess

 

[SlideRuleEra]

...but the excavation has phreatic water in it.

How deep is the water?

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[cvg]

typical procedure here would be to use Controlled Low Strength Material (CLSM). For foundation support, it would probably be 1 1/2 sack mix. That could develop easily over 100 psi strength. Higher strength would require more cement.

I would try and dewater the excavation and if you cant, then additional cement and anti-washout admixture can be added and the concrete can be placed under water. Not sure why you want to mess with plums, it seems to be questionable how much money you would save.

https://www.master-builders-solutions.basf.us/en-us/products/mastermatrix/1785

 

[killswitchengage]

the water i would guess is maybe 1 m deep at its best. personally i don't understand why using plums concrete if after placing it the lowest point of the foundation will be above water ?

 

[bridgebuster]

Here's a blurb I found

Link

A few years ago, I designed a seawall to replace one that was concstructed from cyclopean concrete. However, the boulders were much larger than what is cited in the link; FWIW.

 

[bridgebuster]

On Google Books I found a 1930 spec book by The National Bureau of Standards. Attached are the pages relevant to cyclopean concrete.

 

[Okiryu]

Not familiar with cyclopean concrete but I think that you may still need a kind of “choker layer” in order to provide a uniform work/foundation platform.

 

[killswitchengage]

Thank you all guys