Concrete Curing in Cold Weather Conditions
Heating Method
Heating Method
These are the activities carried out to raise the temperature of the concrete before placing or after it has been placed and compacted. The aim here is to keep the temperature of the concrete at the level necessary to reach the desired strength within the specified time. (see Concrete Maturity).
Heating process
hot weather
steam
electric
is done using
Heating with Hot Air
In this method;
Concrete is poured and cured in volumes heated with hot air.
The volume under the mold to be poured concrete is closed and heated with hot air. After the concrete is poured, the concrete is cured by covering it with a heat-insulating material.
If concrete is to be poured and cured in volumes heated with hot air;
Drying of the air inside the heated volumes should be prevented.
Heaters should not blow hot air directly onto the concrete.
Concrete samples should also be kept within this heated volume.
Cover material with heat and water insulation feature
Concrete
Electric Heating
The electrical heating method of concrete is based on the conversion of electrical energy into heat energy.
The process of transforming energy;
indirect (electrical heating by contact),
direct (heating with electrodes) and
electromagnetic fields (induction heating)
It is done by one of the methods.
Contact Heating
In this heating method, the concretehigh resistanceandinsulated cablesis placed. Electric current is supplied to these cables and the concrete is heated with the heat energy generated by the resistance of the cable.
It is safer as no direct electrical current is supplied to the concrete and does not adversely affect the adhesion between concrete and concrete and iron.
In another contact heating method,heater moldsused.
Preheating with Electrodes
Electrodla concrete in preheating method; It is heated before being placed in the mold.
In order to minimize heat losses, the heating process is carried out in concrete buckets equipped with special heating equipment or in concrete transport vehicles just before the concrete is placed in the mold.
The cooling time of the concrete subjected to preheating is prolonged and therefore the concrete has a higher strength until the freezing point.
During concrete preparation, the necessity of heating the aggregate and water to high temperatures is eliminated. It is sufficient to heat only enough to thaw the frozen aggregate and prevent the concrete from freezing during transportation.
Direct Heating
Due to the resistance encountered by the voltage difference (voltage) given to the electrodes placed on the fresh concrete while passing through the concrete, heat energy emerges .Electrode heating methodIt is based on the principle of using the heat energy generated in this way in concrete curing.
This heating method can be used in all types and shapes of building elements. However, it is more effective in simple shaped and unreinforced or less reinforced structural elements. Electrode heating is a method in which electrical energy is used most efficiently.
