Hearth Slab

[NanaGG]

I'm looking for advice on pouring a hearth slab for my Portuguese WFO. My base is constructed of cinder blocks and I'm thinking of using Perlite and Portland cement in a 5:1 ratio for the hearth slab in about 4" thickness over an area of approximately 35 square feet so we're talking about 12 cubic feet of material. Can anyone tell me how much of each material I'll need and how heavy it's likely to be. I'd also like to know how strong it will be once it's properly cured as there will be some 'overhang' when the support structure is removed.

Thanks for any advice or insight you can offer.

[UtahBeehiver]

Perlite/Portland 5:1 mix is for "insulation" purposes only. You need a regular structural concrete mix portland/sand/aggregate with steel rebar for your hearth. Perlite/Concrete does not have the structural strength.