Cooling Rate of The Precast Concrete Members Worksheet
I’m working on a civil engineering multi-part question and need support to help me study.
Reinforced concrete beams and columns are produced in a precast factory. Concrete members will be heat treated after casting for a total period of 19 hours. Heat curing is designed to cover an initial delay period of 2 hours at 20 °C, heating for 3 hours to maximum temperature of 85 °C, keeping at maximum temperature for 9 hours and then cooling to 20 °C. Beams will be prestressed after heat curing when the concrete should reach to at least 30 % of its potential strength. Cylinder specimens are taken from the concrete mixture for determining the potential strength of concrete after curing them in water at 22 °C till testing at 28 days.
a) Draw temperature vs. time graph of curing procedure applied.
b) Calculate the cooling rate of the precast concrete members.
c) Calculate the strength gained by the concrete member members after heat curing for 19 hours.
d) Is this heat curing cycle appropriate for prestressing the beams 19 hours after casting? If not what most practical change would you propose for the heat curing cycle for the beams.