Concrete Fire Pit Exploding. For those who want to build a masonry fire pit on a concrete slab, you will want to use fire brick for the bottom, laid in with refractory cement or high temperature mortar. Concrete fireplaces and fire pits should be constructed carefully.

It would certainly deteriorate after repeated fires though. If the fire is hot enough for an extended period of time the standard pavers could very well explode in a very damaging fashion. I have also seen bridges made of concrete explode and big chunks fly off because a semi hauliing gas, tipped and caught fire.

This detail is often overlooked by installers but can result in an extremely hazardous situation if aggregate in concrete or cinderblock overheats and explodes.

This detail is often overlooked by installers but can result in an extremely hazardous situation if aggregate in concrete or cinderblock overheats and explodes. I don't think concrete would explode. Because you're planning to place the fire pit at least 20 feet from all structures, including your house, garage and storage or potting sheds. I checked the stone options at home depot & lowes and just the material will cost around $250.