This product, also known as “Recycled Concrete Aggregate” (RCA) is repurposed material, created from crushed-up pieces of discarded concrete. Every time a concrete structure is replaced or removed (think sidewalks, driveways, foundations, etc.) that older concrete can either be placed in a landfill to sit forever, or it can be broken up to be reused as an aggregate material. This material is created through several crushing phases to remove nearly all foreign materials (metal/etc) to create a very uniform product that is something of an affordable hybrid between a Road Base Gravel and Crushed River Rock.
Consider Recycled Crushed Concrete if you are looking for a stable, yet economical option. It is especially well suited for driveway, parking pad, or trail usage.