Guidance on interruption of a continuous pour?

[StructureMan44]

Our contractor was performing a continuous pour for a wind turbine foundation. They interrupted the pour for 45min before continuing. Is this acceptable or does any ACI (or other provider) offer guidance on determining if this interruption is acceptable? Maybe these is some form of testing that can be performed to insure the joint is acceptable.

 

[TehMightyEngineer]

Is the joist accessible/visible from a surface? Or is it length-wise inside the pour?

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[maxdistortion]

What was the temperature? and were there any admixtures in the concrete? How much had they poured and how much did they have left? I can only speak from experience as I haven't dug too much into ACI (CSA for me). I would first get a feel for how cured I estimate the concrete was at the time they resumed pour. Nice thing about concrete is that if they created a cold joint, you would almost certainly see it when they strip it and you are inspecting for release for backfill. I do remember there is standard practice for what percent cured (in strength) one batch is no longer considered monolithic. I guess this is what you are looking for.

 

[maxdistortion]

Looked around a bit but there's not much in term of chart. Portland Cement Association says if the concrete was still plastic then there is no cold joint. If you calculate that you may have a cold joint, try to make yourself, or an inspector available when they strip so you can see if there is a cold joint. Contractors sometimes try to hide the imperfection so better not to give them the chance to see the cold joint first.

 

[jike]

Do you have continuous rebar, top & bottom, going thru the joint? Please confirm.