Concrete curing room construction 5

[jenduro]

Does anybody know what type and size room I would need to store up to 8000 concrete cylinders at one time in a moist curing room? I have looked at converting metal shipping containers, but I would need about 6 of the 40 ft containers to handle this many. I have seen a wood frame construction, insulated with freezer type inside walls, in a warehouse. Are there any better ideas?

 

[emmgjld]

Questions come to mind.
--Is this to be temporary facility, less than 5 years or is it to be permanent?
--What are the environmental considerations? Will it be a challange to maintain temp or humidity?

I can give my personal experience.
The home office had a very well constructed CMU wall and precast concrete lid. The door required replacement every 5 to 8 years. Worked real good for over 20 years.

My office had a CMU wetroom. Poorly put together. Water seepage at the wall/floor connection. The steel door was a rusting hulk. Seven years old and a fiasco. Tore it down.

I built a replacement wetroom out of treated lumber, walls not in contact with the exterior CMU building walls. Used a 'plastic' door. CCRL was approving for 6 inspections. That is 12 years. The lumber and door is now shot and the facility will be torn down in a month or two.

I am finishing the new facility with ICF units and a treated lumber ceiling. I used the ICF for thermal control. Trying to find an equivalent door. The treated lumber and connections to the ICF walls have been coated with a spray-on epoxy and I anticipate 20 years+ of use (should be in use long after I retire). A little pricy but I anticipate no hassle.

 

[Ron]

I have designed and built several moist curing rooms. The shipping containers have the right aspect ratio, but would be extremely hard to control the temperature.

Concrete masonry or cast in place concrete works best. Insulated freezer panels work well, but will corrode.

The roof can be marine grade plywood or cast concrete. Concrete or masonry are good because of their ability to attenuate outside thermal changes.

Make sure you seal the room from the inside to prevent seepage. A good epoxy coating will work well, with appropriate sealants at all joints.

A freezer door will work well for the door. As noted by others, plan to replace it every 8 to 10 years.

 

[jenduro]

Thanks for the information, this facility would be temporary and be inplace for only 2 to 3 years.

 

[Dumitrescu]

Dear All,

Just thinking: aren't we supposed to cure the samples just the same way we cure the structural element?

Replies mostly appreciated


Catalin Dumitrescu,

Bellinghausen Beton SRL
Romania

 

[henri2]

Catalin, it depends on various factors which include amongst other things: the standard practice, the enforcement agency, job specifications and purpose of the test.

I am familiar with ASTM C 31- Standard Practice for Making and Curing Concrete Test Specimens in the Field. This standard is referenced in ACI 318-Building Code Requirements for Structural Concrete and Commentary. For most cast-in-place concrete building structures, ASTM C31 is the standard practice adhered to in the United States

According to Section 3.2 of ASTM C 31, final curing of strength test specimens(after initial field curing) in a lab curing room or tank filled with lime saturated water is done for reasons such as:

1. Acceptance testing for specified strength

2. Checking adequacy of mix proprotions for strength, and

3. Quality Control

Sec 3.3 deals with the situation you describe..i.e field curing adjacent to structure for reasons such as:

(i) Determination of the time the structure is permitted to be put in service

(ii) Comparison with test results of standard cured specimens or with test results from various in-place test methods,

(iii) Adequacy of curing and protection of concrete in the structure, or

(iv) Form or shoring removal time requirements

For Highway projects, state departments of transportation use AASHTO standards; so instead of ASTM C 31, they use AASHTO T23--Making and Curing Concrete Test Specimens in the Field..and typically make ammendments to this document. So while some DOTs require that specimens be cured in lab after initial curing in field, others may not. Example:

http://www.deldot.gov/static/pubs_forms/manuals/mat_research/part_d_doh11.shtml

see Section 7

http://www.nebraskatransportation.org/mat-n-tests/NDR Standard Test Methods/ndrt23.pdf

refer to Section 9

 

[Ron]

Dumitrescu...No.

We obtain and cure test specimens by a standard process, hopefully repeatable among many technicians. The purpose of sampling and testing the plastic concrete at the site is to check the concrete mix design, not the in-place concrete. The design inference is that if you get what you wanted in the mix design, the concrete should be OK in place (that's a BIG inference that is often wrong! due mostly to the variables of placement, site modifications to the mix, improper curing and finishing.

 

[Dumitrescu]

Thanks, Ron,

I agree with you but, shouldn't we have also some specimens that we are supposed to cure JUST LIKE THE STRUCTURAL ELEMENT ? I really do not care what is the concrete plant design for the mix, what I am interested in is that I will have the resistance I accounted for in the design (actually the structural engineer that design the element. Don't you agree?

Catalin Dumitrescu,

Bellinghausen Beton SRL
Romania

 

[Ron]

Dumitrescu....In one respect I agree with you....we should know the in-place strength. Taking a specimen and trying to cure it the same as the structure usually just leads to confusion as the mass and surface area of the specimen are significantly different than the structure, thus the properties do not develop in the same manner or the same time frame.

There are in-situ methods available to determine the in-place strength, though they are usually either destructive or semi-destructive. A few nondestructive methods such as pulse-velocity, pulse echo, and other low-frequency ultrasonic methods may also be used.

 

[Dumitrescu]

Thanks again Ron, you are right! My respects!

Catalin Dumitrescu,

Bellinghausen Beton SRL
Romania