I need to fill in alot of area next to the driveway and have access to alot of rock and some old concrete. Can I port 4-5 inches on top and let it bleed into the crevaces or am I better off just using crusher???
Use crushed stone and compact it, definitely if it's outside. Drainage and weather, and any type of weight on it will expose weak points where the uneven subsurface is lying.