Can concrete demo material be used as fill behind same project?

Question

I am demolishing the old outdoor steps at the rear of my house, built circa 1955. I have discovered that they are not constructed on the ground surface, but sit upon a concrete block structure about 4 feet deep. Underneath the steps is an empty, 4-foot deep pit.

I plan to have a concrete patio surface poured over the area.

Can I demolish the steps into the empty pit, essentially filling with the demo material? Or will the broken concrete and blocks be too unstable a base to build upon later?

Answer 1

Sure, that's fine. The rubble will act as aggregate, and new concrete will bind the it all together into a monolithic mass. This was standard practice back in the day, in fact. And castle walls were built this way too. You'll be just fine; just try to smash the old steps into smaller rather than larger pieces.