What is the ideal slump and mix ratio when pouring a 3 ft. wide sidewalk in 30 degree F weather?

Question

I'd like to obtain the ideal slump & mix in order to get the best workability and strength when it sets. The ones we poured earlier tuned out brittle, so I want to make sure we get the right mixture & slump for the next pour. (Only well informed anwers please)

Answer 1

Here is an article that will hopefully convince you to wait till the weather is warmer.

http://www.nrmca.org/aboutconcrete/cips/27p.pdf

Answer 2

Your slump wont change. I like a 5 or even a seven, but that is mostly personal choice. What you do need to do, is make sure the cement company adds the proper additives to allow you to pour at that temp. If that is a high temp, and is colder at night, forget it, wait until it is warmer, if that is a low temp you can get by with the additives and once it is set up enough not to be marked up, covering it with plastic and then straw, burlap, heavy tarps or some such thing to hold in the heat it naturally makes when curing. Any and every time you pour in weather that is below freezing, you stand a chance of having a bad pour.

by the way, you did not say if that was celsius or centigrade (what the hecke ever they call it these days) or farenheight, i am assuming farenheight because pouring at 30 celsius is not a problem.

Answer 3

Note to tootall1121: the asker did specify "F", as in Fahrenheit.
Puzzling why anybody would try to pour concrete when it's sub-freezing though.