Rockbadchild
Veteran Member
time won't make them crack, I mean Do you use it a lot ?... also would be interested to see how big or little of fires you do.I built a fire pit with landscaping blocks 20 some years ago. It has a dirt bottom but the blocks are stacked up 6 high and about 4' diameter with a lower wall on one side for viewing.
They all cracked but they have held together just fine. In fact, I recently backed into it while mowing and pushed part of it in about 4" and it is still standing solid.
''While concrete blocks are resistant to fire, the materials are not entirely unaffected by high heat. Temperatures up to 420 degrees Celsius can cause the concrete to lose strength and break. At 600 degrees Celsius and above, concrete no longer possesses its full structural capacity.''
''Changes in the temperature of concrete can cause cracking. As the concrete gets hotter, it expands; as concrete gets cooler, it contracts. This is similar for many other materials you have probably learned about. If the concrete wants to expand or contract but can't, it will most likely crack''