Cold weather concrete - cast in place piles 2

[bridgebuster]

I'm reviewing a contractor submittal for cold weather concreting procedure for cast in place piles. The piles are 18 inch diameter monotubes; one location calls for 65' long piles; the other is 90' long. This is a bridge project in the NYC area.

The contractor is proposing to heat the area using light bulbs - yes, light bulbs. My feeling is that this is unnecessary & ineffective. He's proposing to maintain the concrete temperature during placement at around 60 degrees F. I would imagine that after the first few feet from grade the ground temperature would actually be warmer. ACI 306 R10 doesn't address piles.

Any thoughts?

 

[dik]

I've seen lightbulbs used... not common... often just a couple of straw bales over, or an insulated tarp.

It's likely a lot colder in Winnipeg than in in NYC... I wouldn't be too concerned as long as some effort is being made.

Dik

 

[bridgebuster]

Thanks Dik

 

[Ron]

bb...you're right about the below grade temperature...wouldn't worry at all about that. Heat of hydration within the pile will likely keep the top warmer as well. Just protect the very top.

 

[concretemasonry]

The upper layers of the soil are not greatly affected by the air temperature, but are more affected by the natural soil temperatures, which generally increase with depth and are probably close to the average annual temperature in the upper portion. The concrete added during a cold season will probably be greater than the air temperature, which can be very misleading.

Just provide minimal protection to the upper portion of the piles and let the heat of hydration do what it will do as it cures, and hopefully not too fast. Since your concrete mass is not too great, I would not worry too much about the concrete getting too warm because of the natural conditions.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[bridgebuster]

Thanks for the response guys. It's pretty much what I thought.