Steam curing at atmospheric at temperature of 65℃ in a curing chamber accelerates the hardening process. The main benefit of steam curing is the rapid strength gain in the unit, which allows them to be placed in inventory within hours after they are molded, 2-4 days after molding, the compressive strength of the blocks will be 90% or more of the final unltimate strength, besides, steam curing produces unites of lighter color than is usually obtained with natural curing.
Initial temperature of the concrete shall not be raised above 48℃ for a minimum of 2 hours after the units have been cast.
The rate of increase after 2 hour period shall not exceed 15℃/hr and the maximum temperature shall not exceed 65℃
The maximum temperature shall be held for a period sufficient to develop the requied strength (4-5 hours)
Rate of decrease in temperature shall not exceed 10℃/hr
Units shall be kept covered for a minimum of 24 hours after casting