The Mass Temperature Controlled Concrete has its very specifically defined Specifications given by Designers and Consultants (Codes) .Still in response for your queries can be answered as follows :
1) how much temperature is required during placement of concrete ?
Ans: The controlled temperature shall be kept ranging 21-24*C keep all others factors and constraints .
2) what is the temperature difference surface to the core ?
Ans: The differential variance shall not be greater than +/- 20 *C . (Shall be monitered upto 4 days )
3) Size of ice flakes used in concrete mixing
Ans : It depends upon the setup of production unit ,if there is chiller plant than qty of water shall be replaced by 20% of ice keeping productivity in mind .
4) any bleed spots are observed as ice flakes are prone to bleeding.
Ans: No, The uniform mixing shall be observed and then batch to be discharged . Unmelted ice may lead to vary in temp .
5) rise in temperature in core after 72 hours
Ans : The common observation has concluded as maximum rise in temp is at 62-64 hrs then it comes droping .
6) why we use temperature controlled in raft ? (except the reason HOH)
Ans: Please go through IS Codes for temp controlled and Hot weathered Concrete ,This will give you more answers in this context .
7) what kind of mixer is used to produce this concrete?
Ans : Batching plant can be used of capacity from 0.5 to higher side .
I hope this will atleast resolve your queries for now , Lets keep it interactive to discuss this wide subject in details .