Pouring Concrete Walls In Lifts

If too much concrete is poured in one place at one time the pressure build up could become too much for the icfs to handle.

Pouring concrete walls in lifts.

This is done in multiple lifts of around 4 feet or less. In this project 40 foot concrete walls were poured using formwork rated at 1650 psf. In actual practice each wall was completed in a single continuous pour in one day. The layer thickness ranges from 300mm to 500mm and the time between successive layers should not exceed 30 minutes for normal weather condition and 20 minutes for hot weather condition.

Pouring of concrete in columns and walls if the height of these elements is large then it is recommended to place concrete in layers. The 4 foot lift height is a recommendation as a guideline to. How to pour concrete in columns and walls. If the full hydrostatic pressure assumption was imposed the lift height would be limited to 11 feet requiring more than three separate concrete placements.

Finish the surface of the wall as desired. Make multiple passes if needed to create a flat evenly filled area. In commercial construction walls may be higher 14 to 18 feet. Drag a straight 2x4 screed board across the top of the concrete forms to level the concrete.

By pouring in lifts the first part of the concrete starts to set up slightly slake reducing pressure on the lower forms. This placement method is a standard practice in the icf industry. Have a helper add or remove concrete in front of the screed as you pull it. Allow concrete to cure.

The basic principles of placement and vibration are the same for any placing equipment used. The pressure in the icf forms is based on how high the concrete is poured at once. If the height of the wall or column form is not considerably long pour concrete from the top of the forms. Pour concrete in layers with a thickness ranging from 30cm to 50cm if the height of the rc column is large.

Pour and level the concrete. Reduce cold joints honeycombing and bugholes by training workers how to place and vibrate concrete in walls. Place concrete at or close to its final position. Available from diy stores and ready mix concrete companies these contain soluble emulsions that form a protective film when sprayed directly onto the surface of newly poured concrete slabs or walls.

If problems occur however corrective action can minimize their recurrence. Create contraction joints every 4 6 feet. Wall to a maximum of 10 to 12 feet in height during one concrete pour. These walls also have the concrete placement in multiple lifts following the same procedure.

Place concrete walls with a maximum 60cm layer in one pass to avoid segregation.