Curing time and removal time of Formwork

Curing time and removal time of Formwork

Curing :

What is curing of concrete ?

      Curing of concrete is defined as the process of maintaining the moisture and the temperature conditions of concrete for hydration reaction to normally so that concrete develops hardness properties over times.

Duration of cement

     The curing of concrete can make the concrete stronger and increase it's strength. It can increase the durability of concrete. The duration of curing depends upon the weather conditions. If the weather of such are is warm or highly temperature then it take more time and days for curing some time curing time become double with respect to weather conditions. If the weather is cool or low temperature it will manage differently

       OPC = Ordinary Portland cement = 10 days
       Super sulfate cement                    = 7   days
       Mineral cement                            = 14 days

Types or methods of curing

There are two types of curing

1.  Ponding method
2.  Wet covering

Ponding method

This method is adopted in floor slab. Make some ponds on floor slab depending on the size of floor and fill it with water continuously for 14 days for curing concrete.

Wet covering method

This method is usually use for the columns, footings and bottom surface of slab where ponding mehod did not work or possible. In this method the gunny bags and hessian are use to cover the concrete and keep wet them with water.    

Why curing is necessary ?

               The curing of concrete is requires for the following reasons :

1. To prevent the concrete from drying out permaturely due to solar radiation and wind.
2. To maintain the concrete temperature by allowing the hydration process.
3. To prevent the concrete from drying out prematurely due to solar radiation and wind. The prevents plastic shrinkage of concrete.
4. It helps to maintain the concrete temperature.  It require water to carry on and release heat.
5. It helps the concrete to bond with other internal material and reinforcement.
6. This helps the develpment of impermeable, crack-less and long time reliable.

Factors which depend on curing

1. Specified the strength of concrete
2. Grades of concrete
3. Atmospheric temperature
4. Shape and size of concrete