Mass concrete pours are planned with C60 CYLINDER strength mix with 30% Flyash and 7% microsilica. The specs calls for ACI 301 limits on temperatures (70 Deg C max peak internal temp & 20 Deg C differential). A mock up cube 2mx2mx2m was casted during winter season and fresh concrete temp = 20 deg C. The thermal readings achieved the temp limits. (69 Deg C and 17 deg C) and the mix was approved.
Now, we are in summer season where ambient temps are above 40 deg C and adding 80-90% of ice flakes to the mix but fresh temps are not reduced below 26-27 deg C. Other than using ice, aggregates are shaded to reduce the fresh concrete temp.
On actual rafts with thicknesses 3-4 meters, the above mix in hot weather will exceed the 70 Deg C limit. So, we proposed ACI 201.2R16 that allows peak concrete temp upto 85 Deg C IF flyash and microsilica are used but the proposal was not approved.
Also, the raft thickness has proportional influence on peak core temperatures.
Mix has 520 Kgs of total cementitious material @ 0.3 W/C
What are your thoughts on ACI 201.2r16 recommendations that allows peak temps up to 85 deg C if the mix has flyash atleast 25% and 5%microsilica? And, other than using GGBFS, what are other options to achieve ACI 301 temp limits, for a high strength mix as 60 Mpa and pouring in a very hot weather area of the world.