[Greenbuilding] R-value of crushed stone under slab

[Norbert Senf]

Google says specific heat of concrete is approx 0.8 kJ/kg-K
1 MJ = 1000 kJ
Density of concrete = 2300 kg/m3

This gives you a specific heat of 0.8 x 1000/2300 = 0.35 MJ/m3-K

A normal concrete mix = 1:2:3 cement:sand:gravel.
The sand fills the voids in the gravel. Therefore, for concrete with 40%
voids (ie., for gravel), the specific heat would be .14 MJ/m3-K

Norbert

On Mon, Dec 7, 2015 at 10:06 AM, Alan Abrams <alan at abramsdesignbuild.com>
wrote:

> a recent project required a lot of fill under an insulated slab. washed
> crushed bluestone (aka #57's) was used for the fill, at an average depth of
> 24"
>
> any advice on how to calculate the following:
>
> R-value of the crushed stone
> Heat capacity "  "  " , expressed as MJ(m^3K)
>
> ?????
>
> aa
>
>
> Alan Abrams
>
> *certified professional building designer, AIBDcertified passive house
> consultant, PHIUS*
> *certified passive house builder, PHIUS*
> cell     202-437-8583
> alan at abramsdesignbuild.com
> HELICON WORKS *Achitecture and Education*
> <http://www.heliconworks.com/index2.html>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>



-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20151207/23353b6a/attachment.html>