Curing Room for Concrete Samples

[CrusherGal]

I work on a remote Northern site that will have a huge amount of concrete cylinders over the next 4 years. After the project is complete we will be moving all the equipment to another site.

I am concerned if we have a break down that it is not easy to get replacement parts to site in a timely manner. Also that in the very cold in the winters & how will the room react? We will be using a 20' insulated c-can.

Is it better to set up a curing room or continue on with just tanks?

 

[Ron]

Tanks are ok for small volumes; however, the temperature is more difficult to maintain in tanks than in a properly controlled curing room.

Consider hot water for your humidification, supplemented by heaters. In warmer weather, you can always go back to unheated water.

 

[csd72]

Shouldnt the samples be kept in the same conditions as the actual concrete member?

 

[CrusherGal]

There will be field cure samples which are kept in the field under the same conditions as the pour. The room is for the lab cure samples.

 

[Ron]

Field cured samples rarely replicate the conditions of the in-situ concrete and their strength does not necessarily correlate with in-place strengths. I wouldn't waste my time with them.

The lab samples are to check the mix design, not the in-place material. The design assumptions have to consider the mix design characteristics and strength. That's what you're testing...not the concrete in the structure.

 

[CrusherGal]

Thanks Ron, I am on the same page as you but it is the client and their Engineering group that require field and lab cures.

I am more concerned about setting up the cure room correctly.

 

[concretemasonry]

What is a "huge amount" of samples for lab testing of delivered concrete samples for 28+ days plus holding the site cured samples for a day or so when you get really cold.

I was on a large construction project (3+ years duration) that tested a lot of concrete. We had a test facility and the curing room was 8" or 12" solid concrete block walls (for thermal inertia) with exterior insulation to maintain uniformity of temperature and humidity (-50F one morning). - Water mist and the heat of hydration maintained the temperature within ASTM requirements well after we installed an automatic closing door.

The building was planned to be scrapped after the project, but the owner decided to keep it for future use for other purposes.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[CrusherGal]

We will be pouring approx. 250,000 cubic meters of concrete. Which will work out to approx. 30,000 cylinders over the project.

We will be storing 7, 14, 28, 56, and 91 day cylinders (both large and small cylinders. Plus grout and shotcrete samples.

We have been provide a 20' insulated C-Can/ Connex. I haing a problem locating a waterproof heat system. As for the cold, well we have 4-5 months of -30C then all summer with +35C.

Thanks for all the tips.

 

[henri2]

For commercial construction, field cured cylinders are not usually required. Some projects do require them, however, for some of the reason outlined in ASTM C31-06 Section 4.3.

 

[CrusherGal]

Field cures are required by the owner, therefore we must follow their specifications.

 

[concretemasonry]

The owner pays the bills, so the requests/requirements must be followed.

From a liability standpoint make sure the field curing is documented with date stamped photos. Field curing may follow the guidelines, but there are holes in the process and it does not accurately reflect the in-place concrete properties.

The field curing does not provide a positive track that shows that the supplied concrete is equivalent what was approved, but just shows that the cylinders showed adequate results for the conditions imposed.

After a few summers of inspecting and testing concrete while in college, I learned many of the tricks to get either good or bad cylinder test results while still staying within the ASTM standards for sampling and sample preparation thanks to a contest or two during a supervised concrete class in college. No sugar in the concrete or wires in the cylinders were allowed in the contest.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.