Lab curiung of test cylinders

[mikeofBelAir]

New lab for me, and I need to get it ready for CCRL.
We use 5 tanks for lab curing of the cylinders. They are in a temperature-controlled room. If we can keep the room within the temp specs for curing do I also need to monitor the tanks? Our tanks are separate--no circulation between the tanks. If I need to document their tank temperature, I will need a monitor for each.
I see that there is a 4 channel data logger available from various suppliers. I could use 2 of them and monitor all 5 of my tanks and the ovens used for soil testing. Does anyone have experience with these data loggers?

Here is a link to the data logger:

http://www.globalgilson.com/4-channel-data-logging-thermometer

 

[appot]

For air curing, the curing temperature is the temperature of the air directly surrounding the concrete or cylinders.

Using common sense, the temperature of the tanks will equilibrate to the temperature of the room. The only caveat being, did you just add two pails of 33°F water to the tanks?

If you can easily monitor the tanks, I would do so. How are the tanks heated? Is there a thermostat and a heating coil? You should be able to get a submersible high-low thermometer:Thermometer (I do not know if this is submersible, but I don't see why it would not be)

 

[mikeofBelAir]

We don't have the tank heaters in the tanks at this point--checking to see if the room temperature works to maintain the required temps.
Evidently, thermometers in the tanks doesn't meet the requirements as we must have readings at a max of 15 minute intervals. While we could station a tech there 24/7 to do that, I don't see that as cost efficient.
We are currently reading an logging the temps throughout the day, but understand that we need full time data logging. That's why I am looking for someone with experience in the 4 channel unit I posted in the first post.

 

[BigH]

Measuring temperature every 15 minutes?? This has caused me to read ASTM C 511. I'd like to see those who write this spec work in places like India, China and other SE Asian countries. I've excerpted the paragraph from C 511 on tanks. It implies that if you can control your room temperature to within the specified range, you do not need the recording thermometer. Now in practice (in the countries I've mentioned) there is no way that this spec could be met (this sounds like a research oriented spec or perhaps for very complex concrete requirements). I've talked in the past to some pretty well known experts and one was trying to get curing for field labs to be a lot less stringent. Also some countries have different standards - ASTM it is 23 degC; in Indian Standards it is 25 deg C (if my memory is serving me correctly). Seems to me this is seeking too much perfection for standard practice - but . . . so see the excerpt below.

From ASTM C 511
"Tanks shall be constructed of noncorroding
materials. Provision for automatic control of water temperature
at 23.0 +/- 2.0°C shall be made where a tank is located in a room
not having temperature controlled within that range and in any
other instance where difficulty in maintaining temperatures
within the specified range is encountered. Each tank located in
a space not controlled at 23.0 +/- 2.0°C shall be equipped with
a recording thermometer with its sensing element in the storage
water. Water storage recording thermometers shall be checked
for accuracy at least every six months by comparing their
output with that of a reference thermometer placed in the water
adjacent to the probe of the recording thermometer.

 

[Ron]

I agree with BigH.....even with tanks in a controlled temperature room, the lag of temperature change in the tanks can be significant if you introduce more water or if the room temperature changes. Monitor the tank water temp...not that difficult or expensive.

 

[mikeofBelAir]

Thanks for the replies.
One of the problems I am having is accessing the ASTM website. I can get into vol 4.08 for soils, but there is a problem seeing vol 4.02 which is the concrete volume--and where C511 is located. That means I have not been able to read the latest version.
What I am going on is the information provided by re:source which used to be CCRL. Their newsletter from April 2014 addresses ASTM 511 and curing facilities. Among the common errors they list is the failure to evaluate records of weekly temperature data. Later on they have this paragraph:
Digital vs Chart Recorder
One of the requirements of ASTM C511 is that your curing facility must be monitored by a temperature recorder. The temperature recorder must be accurate and readable to 1 degree C and shall be capable of recording the temperature at least once every 15 minutes....

 

[Ron]

One of the CCRL requirements is that you have the current applicable standards. Time to invest!

 

[mikeofBelAir]

Done! well sort of....
I had my office manager and one other full-time employee join ASTM as participating members. One of the benefits of that is you get a free volume of the Standards of your choice. We got 4.02 Concrete, and 4.08 Soils and Rock. The password works for 4.08, but after 3 weeks still cannot gain access to 4.02

As soon as ASTM solves the problem, I will have access to the Standards I need.

 

[TigerGuy]

We use a similar recording thermometer in our tanks. Pull the memory card and dump data to the computer once weekly, print, verify temperature stayed in proper range, file, repeat.

 

[BigH]

. . . once a week - and what if it didn't stay in the range??