what is column casting
Cast-in-place concrete is a technology of construction of buildings where walls and slabs of the buildings are cast at the site in the formwork. ... It uses concrete slabs for walls instead of bricks or wooden panels, and formwork is used for both walls and roof.
How To Cast Concrete Column
1. Collect samples for maturity testing. Check slump and temperature if inclined with what’s designed. Concrete should not be “freshen up” with water or re-tampered in any way.
2. The surfaces of construction joints should the thoroughly wet, free from laitance before pouring fresh concrete.
3. For the casting, deposit concrete continuously. Make sure that concrete is cast as neatly as possible and avoid considerable height difference that promotes aggregates segregation. Use chutes if necessary. Make sure that no concrete that has already settled or “unworkable” is used, or does not meet the required quality control limits.
4. Concrete pumps (lubricated using mortar before starting the work) may be used if necessary.
5. Concrete mix should be used and cast within one and one-half hour (1 1/2) after water has been added to the dry mix.
6. Should the weather does not permit the ongoing concreting works; proper construction joints should be established as per specifications and at the location where the stress is minimum.
7. As much as possible, avoid cold joints by placing layer by layer while the concrete is still in plastic form.
8. Remove the temporary spreader (if used) in the formworks when the concrete placing has reached the elevation of such spreader.
9. The concrete should be compacted using a mechanical vibrator. The use of vibrators should be limited to the time necessary for consolidation. By any means, do not vibrate forms or reinforcement. Under no circumstances should they be allowed to cause aggregate segregation. Prepare for spare vibrator should the other one malfunction.
10. Strictly speaking, concrete should be cast max 0f 2 hours after leaving the batching plant (for ready-mix concrete).
After the concrete has settled and has attained its designed strength safe for stripping, removal of formworks may commence. Should there be any defect or noticeable bulges after the removal of formworks, it should be rectified by the means of chipping, grinding or any approved tools.
#ColumnCasting #RCC_Column #Casting_of_concrete_column #in_hindi
