refractory castable for floor

[chale]

I have seen previous posts for potential use for castables for the pompeii floor. From reading the pompeii pdf, it says that low duty bricks contain about 50% silica and 30% alumina. The instructions also indicated to stay away from refractory insulating bricks because they will not absorb heat enough.

That being said, there is a refractory insulating castable for sale on ebay [Pacocast 24 by Resco products] that has a similar silica/alumina ratio....BUT it is referred to as refractory insulating castable. So is this usable for the floor or dome?

[dmun]

No. It's an insulating product, like a very expensive vermiculite concrete.

[Johnny the oven man]

Insulating castables are in most cases very soft, so abrasion would also be a big problem. The denser the better for the base.

[wemme]

So if the chemistry is *about* the same how can you tell them apart.

Regards
Bart

[Johnny the oven man]

Way different " chemistry ". Instead of Chamotte or fired brick grog, or Andalusite , vermiculite is used, very lightweight aggregate. Insulating castables have bulk density in the 750 kg/m3 range vs 2000 kg/m3 and more for the dense grade. Even dense castable is a no no for the cooking surface as it always "chalky ", who wants to eat dust in their pizza? You can tell by looking at the dry mix compound, put a small cupfull in your hand and see if you can see hard aggregate or small little 'concertina' shaped vermiculite pieces. This is the expanded or exfoliated light weight product. Better off using fired tiles or pavers. Gee, I have learnt something in 30 years in the refractory game, who would have thunk..........