Laying half fire bricks onto reinforced concrete base

[GeofE]

I am building my own external wood oven.

I have built the base and have a 5 inch reinforced concrete base. I have purchased some half fire bricks for the base/hearth (230 x 114 x 32mm). So with the refractory cement layer there will be a heatproof thickness of about 40mm between the burning wood and the concrete base.

Question I have is, is this enough to protect the ordinary concrete base from fracturing/cracking with the heat?

All opinions & advise greatly welcomed

Geof

PS. Hello everyone

[leckig]

If I understand this correctly, you have no insulation layer on the top of your concrete base?

I dont think you should worry about protecting the ordinary concrete. The main issue is that you will lose so much heat with no insulation.

[Neil2]

If you take portland cement based concrete up through about 550 F, it will deteriorate.