Mass Concrete

[todd2ny]

I have a question as it relates to mass concrete. We will be utilizing a mix with 70% slag. I have heard that the cure times are longer with a high slag concrete in cold weather. Does anyone have any thoughts on how long the concrete curing time is for this mass concrete in cold temps? In other words, how long must the forms be left in?

Thanks

C.

 

[civilperson]

The forms may be removed as soon as the concrete will support the design loading of the selfweight of the member. 75% of F'c is another rule of thumb. Field cured cylinders, (under the tarps with the member), are good guides of achieved strength. Make an extra three or four cylinders and start breaking after 72 hours.

 

[oneintheeye]

rate of strength gain is slowed considerably by use of slag. Sometimes as low a 25% at 3 days.