Initial 24 hr curing temeratures
Initial 24 hr curing temeratures
(OP)
I recently had a few test cylinders cure in the initial 24 hr below the CSA standard of 20 +/- 5 deg. C. My cylinders cured between 15 deg C to in one extream case 2 deg C. All my samples however passed the 7 day test above the required 30 mPa averaging 31 mPa. Would the initial curing time have a tremendous affect on the strenght? If it did would my cylinders not have a low mPa value? And finaly should I be really worried about this, Keep in mind that up here in the north temperatures can drop down quickly at night.
On smaller projects I have been through this and never had any problems. This projects engineer is laying a egg.
I am now curing my cylinders in a heated room. Even though I told them the trailer vibrated too much.
On smaller projects I have been through this and never had any problems. This projects engineer is laying a egg.
I am now curing my cylinders in a heated room. Even though I told them the trailer vibrated too much.





RE: Initial 24 hr curing temeratures
RE: Initial 24 hr curing temeratures
RE: Initial 24 hr curing temeratures
RE: Initial 24 hr curing temeratures
Dik
RE: Initial 24 hr curing temeratures
I had a engineer in our office tell me that there are some cases that the concrete stregth will be higher then what it is if you cure it below the corect temp. Has anyone heard of this before? All studies and reports I've read show that the 7-28 day stregth is 20-30% lower then a properly cured cylinder but the concrete will achieve a higher mPa pass the 90 days then if properly cured.
Freezing a floor slab or a mass amount of concrete is a little different then freezing a cylinder. I have froze a cylinder once apon a time and it broke at 12.5 mPa, but the barier that the concrete was used for was fine due to the heat the concrete released.
RE: Initial 24 hr curing temeratures
RE: Initial 24 hr curing temeratures
Concrete strength test specimens not provided the specified Initial Curing environment may not produce meaningful reliable results. High strength concrete mixes (5K psi to 10K psi), high early concrete, and slag concrete mixes, are particularly sensitive to daily high and low temperature extremes during the Initial Curing period. Concrete strength test specimens subjected to overnight temperatures lower than the specified standard may produce slower strength gain than the mix design values. If early cylinder strength tests are required for post-tension tendon stressing and/or formwork stripping the schedule may be impacted by low breaks caused by inadequate Initial Curing.