Thermal resistivity 3

[BJC]

Is ther a good reference to to find the thermal reisistiviy of concrete?
What I am looking for is a reference for mix types. If I call the local batch plant and get mix # XXX ( I would assume made to an ASTM or some standard) is there a reference to get the Rho (thermal Resistivity- in units of C-cm/wat ).
I am using this in an electrical duct bank and the easy way out is to use a Rho of 55 as given in the National Electrical Code. I have read that the thermal resistivity can vary with cement content and aggregate.
Is there an ASTM standard that i could refer to?
Thank you for your pateience in reading this, this has probably been addressed in this forum already but i haven't found it yet.
BJC

 

[GeoPaveTraffic]

I have never seen anyting like what you are looking for. I believe you will either have to assume a value out of standard table or text book or have a laboratory test ran.

Also, there are no "Standard" concrete mixes. There may be some local standard mixes in different areas of the country, but overall there is no standard to mixes.

 

[jheidt2543]

I think that GeoPaveTraffic is right, however you might try contacting the Technical Servcies Departments at ACI and PCA. They may have some information on what you are looking for.

 

[DRC1]

Contact Geotherm (

http://neptune.on.ca/~geotherm/)

Phone (905) 727-6448
They do thermal testing of concrete for the power industry. My understanding is that they can help devlop trial batches, but some testing must be done to insure R values are obtained.

 

[BJC]

Thanks to everone.
I use to work construction projects and we always built an on-site batch plant. They were set up with recipes for different mixes. The first plant I worked on used punch cards the last one used a PLC to get a mix "number". I though the mix numbers were to some standard.

No matter what the mix we always did slump test and took sample cylinders to break at intervals after the placement.

Thanks again