insulation option

Would Pool Krete be an acceptable option for insulation on a mass heater? It is filled with vermiculite and cement and seems to be a possible, solid option for insulating the riser. Think it's a possibility?

If there's concrete in it, it's no good for that part!

http://en.wikipedia.org/wiki/Concrete#Properties

http://fr.slideshare.net/DeadP/fire-effects-on-concrete

Jon Lim : Not to throw the baby out with the Bath water ! Lets look at this a minute ! Where there are problems there are solutions !

A quick study of the articles provided by Max will show you the basic Portland-type cement problems. There exist different types of non-Portland
cement Called Geo-polymeres that could be, I Think, used in a vermiculite, or perlite mix. Also sodium or potasium silicate (water glass)
can be used as an additional stiffener of traditional materials used in making Heat Risers.

If A high temperature geo-polymer type cement (glue may be a more accurate term here ) was mixed with vermiculite then further research
could find us a new type of insulating material, I would expect it to end-up costing more, and much more of it being needed to provide similar
amounts of insulation !

This is coming from a man who has repeatedly warned against portland-type cements (almost all concrete made in the Americas is Portland )
and is very close with a buck ! Big AL

Well, portland can be used if contained by an envelope, like refractory tubing for the heat riser, and metal container to hold the concrete insulation mix. But then, why use concrete.

I have also mixed "ciment fondu" with vermiculite with good results. But it's not that insulative compared to other materials.