Steam Curing of Concrete

April 21, 2020

Steam curing of concrete is the method of curing the concrete elements in water vapour. This curing is performed either under atmospheric pressure or high-pressure steam. This method is used where there is a need for accelerated strength gain and the concrete requires additional heat to perform hydration. This is done in low temperature zone.

This technique is used for gaining high early strength and this requires for the manufacture of precast and prestressed concrete units.

Steam Curing can be performed by two methods:

Ø Steam Curing of Concrete at Atmospheric Pressure: The steam curing process is performed within a temperature range of 70 to 90F per hour which is merely dependent on the size and the shape of the concrete element. In this steam curing is done in an enclosed chamber in order to avoid any sort of heat loss and moisture. The properly hardened concrete is applied to the steam enclosure after a delay period of 3 hours. It is not exposed directly to the steam just after the hardening. Once placed in the steam enclosure, it is kept for 3 to 5 hours. Normally, this time range would make concrete gain its maximum early strength.

Ø Steam Curing of Concrete by High Pressure: This method is used for small manufacturing units. This curing process is performed with autoclaves at a temperature range of 3250F to 3750F and a pressure range of 80 to 170psi. The concrete produced by this method ought to have no efflorescence, low moisture content after the curing process, better sulphate resistance, less creep and shrinkage, the strength gained at 24 hours is equal to the 28th-day strength under ambient curing conditions.

Advantages of Steam Curing

Ø This is best suitable curing concrete during cold weather condition for rapid hardening of concrete.

Ø High early strength can be achieved.

Ø It increases construction speed.

Ø Stem curing is fast compared to other curing methods.

Disadvantages of Steam Curing

Ø It is not favourable for large surface.

Ø It can be carried out by skilled workers.

Ø The initial cost of steam curing process is very high.

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