how to mix heat proof/fire proof cement for a bbq?

Question

I'm looking to build an outdoor barbeque/firepit. It's a particular style of bbq that I saw in argentina that resembles a stone oven. I need to make a slab about 3-4 inches thick that will be the surface where the fire/coals will rest on. This surface will have brick walls on three sides and a cover above. From memory I know that cement/concrete cracks, pops, expodes when you have a fire or high heat on it.
Is it possible to mix in more rocks, or more sand or something to make it heat proof? Or is a totally different product needed?

Answer 1

With all due respect, I've been in the trades a long time, and fire/heat resistance isn't so much an issue with concrete, especially a slab that thick. I use premix all the time and have BURNED on it with no problems ever.

Your issue should more relate to the type of brick, IE: as in FIRE BRICK. Beyond that, unless your building a FORGE, or super heating with some High level combustable, wood or coals alone will not create enough heat to crack concrete.

Steven Wolf

Answer 2

Just to add a little something, you are more prone to popping or splitting if you have a lot of air pockets in the finished mix. Take a little extra time to get the air out as these pockets are what actualy explode when they get too hot.

Answer 3

what you need is a product called fire clay which is added to the mortar and sand mixture. You can find this at any mason yard. Fire clay has a much higher heat tolerance than mortar alone and will prevent cracking. while it is typically not used on fireplaces i would definately recommend it for a barbecue.

Answer 4

put a layer of 1 1/2 in. firebrick on the bottom if you are worried, i dont think you will generate enough heat to hurt a slab that thick....