In normal circumstances (generally where temperature are above 200C), and where ordinary cement is use, forms may be struck after expiry of following periods:
| Walls, columns and vertical sides of beams | 24 to 48 hours as may be decided by the engineer in charge |
| Slabs (props left under) | 3 days |
| Beam soffits (props left under) | 7 days |
| Removal pr props to slabs(a) Spanning upto 4.5 m
(b) Spanning over 4.5 m |
7 days
14 days |
| Removal of props to beams and arches(a) Spanning upto 6 m
(b) Spanning over 6 m |
14 days
21 days |
For rapid hardening cement 3/7 of the above period will be sufficient in all cases except vertical sides of slabs, beams and columns which should be retained for 24 hours.
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While filling the RCC column (with Box) with concrete, should it be filled to the full height of the column in one stretch? The common domestic construction practice is the column box is mounted ti half the height of the column filled with concrete on one day, and box is dismantled after setting and again mounted up to remaining top half and filled with concrete on another day.
Is it a correct practice?
My doubt is that will there be proper bonding between the already set concrete layer with the concrete poured over that then.
Request clarification from Civil Engineers please