concrete casting

it is preferable not to cast concrete when temperature reach above 35, but still you can add admixtures to the concrete mix to reduce setting time.

the best practice, is to start casting 2 hours before sunset so you can cure the concrete in the absence of direct sunlight.

also many considerations to be taken in the mix design, like iced water, temperature control gauges, superplastesizers, etc.

regards,

Wadid advised Best

Information from this site might help.

http://www.buildernewsmag.com/viewnews.pl?id=457

Use a Sleeping Admixture such as "DELVO" This will put the hydration of the concrete asleep of a certain amount of time (this will allow you to work the concrete before it sets. You can also use (as someone also Suggests) a super-plasticizer. This will increase viscosity while the sleeper delays hydration. These will not effect the strength of the concrete. DO NOT add more water as this will weaken the concrete dangerously. The concrete just needs enough water to eventually (after sleeper and plasticizer have done their work) to set the concrete at maximum strength. Ask for a sample of products from different companies.

Try SIKA, BASF.

goodluck

Very carefully, I might add to Wadid2's comment. I worked one summer for a Saudi customer who was buying concrete dormitory units from a plant in Mobile, Al. They would inject steam into the batch in the winter and ice water in the summer- all in their own on-site batch plant, along with lots of other admix stuff to make the concrete flow into the 4" walls of the vibrating steel forms. In spite of the care they used to control the temperature of mix, there were many days that I would watch some poor grunt with an air chisel trying to peal the flash hardened concrete out of the bucket. Keep your chisel handy. Good luck.

use a retardant, low heat concrete, and keep water on the surface.