👉Possible Reasons for Removing Column Formwork at 8 Hours
1. Rapid-Hardening (High Early Strength) Concrete Was Used
If the contractor used rapid-hardening cement (RHC) or an accelerator admixture, the concrete can gain enough strength in 6–8 hours to allow formwork removal.
Example:
Quick setting concrete
Concrete with calcium nitrate/calcium chloride accelerators
Special high-early-strength mix
2. Very High Temperature Curing Conditions
In hot climates, concrete gains strength faster.
If the temperature is 30–35°C+, the surface concrete may harden quicker, sometimes allowing earlier removal.
3. Contractor Working Under Time Pressure or Poor Planning
Sometimes the contractor removes formwork early to:
*reuse formwork
*push schedule
*continue work above
***This is not a valid technical reason and is risky.
4. Very Light Formwork (Only Side Panels)
For columns, removing only the side panels earlier is possible because the column carries no load from above at this stage.
But 8 hours is still too early unless concrete strength is verified.
❌ Why It Is Usually NOT Allowed
Removing formwork at 8 hours may cause:
*surface damage / honeycombing
*corners chipping
*loss of shape
*structural weakness if strength is too low
Concrete normally needs:
5–7 MPa minimum strength before column formwork removal
Usually achieved at 24 hours, not 8.
✅ Correct Professional Answer
Formwork removal at 8 hours is only acceptable if the concrete is high-early-strength or contains an accelerator and if strength has been verified. Otherwise, it is not recommended and can damage the column.
@etconp
1. Rapid-Hardening (High Early Strength) Concrete Was Used
If the contractor used rapid-hardening cement (RHC) or an accelerator admixture, the concrete can gain enough strength in 6–8 hours to allow formwork removal.
Example:
Quick setting concrete
Concrete with calcium nitrate/calcium chloride accelerators
Special high-early-strength mix
2. Very High Temperature Curing Conditions
In hot climates, concrete gains strength faster.
If the temperature is 30–35°C+, the surface concrete may harden quicker, sometimes allowing earlier removal.
3. Contractor Working Under Time Pressure or Poor Planning
Sometimes the contractor removes formwork early to:
*reuse formwork
*push schedule
*continue work above
***This is not a valid technical reason and is risky.
4. Very Light Formwork (Only Side Panels)
For columns, removing only the side panels earlier is possible because the column carries no load from above at this stage.
But 8 hours is still too early unless concrete strength is verified.
❌ Why It Is Usually NOT Allowed
Removing formwork at 8 hours may cause:
*surface damage / honeycombing
*corners chipping
*loss of shape
*structural weakness if strength is too low
Concrete normally needs:
5–7 MPa minimum strength before column formwork removal
Usually achieved at 24 hours, not 8.
✅ Correct Professional Answer
Formwork removal at 8 hours is only acceptable if the concrete is high-early-strength or contains an accelerator and if strength has been verified. Otherwise, it is not recommended and can damage the column.
@etconp
1 comment
Tseganesh Chima
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