GBlist: Re: mg additive for cement?

Ron Sutcliffe (
Tue, 04 Mar 1997 11:19:15 -0700

Dear greenbuilding list;
I would love to hear your thoughts on this.

Richard Muir wrote:
> >> in Edward Mazrias' _The Passive Solar Energy Book_ he mentions bricks with
> >> a magnesium additive that greatly increases conductivity. Is there a
> >> similar additive for cement available?
Ron asks;
> >Why would you want to increase the conductivity of cement?
richard responds;
> I'm just wondering if a *cheap* additive could be put in the
> mix while pouring a (passive solar) floor to increase it's heat
> conductivity and therefore it's ability to store more btu's.(Or more to the
> point, use less concrete for the same effective heat sink)
> Any thoughts? Richard M

Ron's reply;
To my knowledge thermal conductivity has nothing to do with thermal heat
storage per se. I believe that the thermal heat capacity of the material
is the parameter of interest when discusing a materials ability to store
heat. As such I don't personally know of any additive that will
increase heat capacity in concrete without substantial ammounts of the
stuff. Anyone else?

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