stone wall foundation;40ft x 80ft;best 95% compt. fill

40'x80' that's a slab. Check your dimensions.

Concrete waste, unless it has been ground to the size of gravel will make a very very poor base for anything. Dense graded aggregate (DGA) is your best bet.

thanks/tb

Filling in with concrete waste will more then likely leave voids near the wall allowing water an easy access to your wall. While compacting it it might also push in on your walls damaging them.

At our mining sites we have 3A mod or 3M it's basically a 3" max stone down to 200 mesh, it might be similar to your "3b mod". 2A mod and 2RC should work also all depending on compaction technique. Another by-product you might want to look into is RAP "recycled asphalt product" you should be able to get that for free from your local road crews. A clay fill would be you best bet.

thank you/tb

Use stonedust available at stone crushers, and cost wise it is cheap, The depth of filling is 10 feet- stone dust is very useful like this sites.

The best material is 3/8" pea gravel, since it is considered 100% compacted on placement and minimal vibration. However,, it can be moved around easily since it lacks any binding materials. Class II Aggregate Base rock works quite well, or clean sand. Both are easily compacted over a relatively wide range of moisture contents. Concrete waste might not qualify, since many times there are requirements for the mzximum size of gravels in the materials (usually under 3"), plus depending upon the shape, voids can form under the concrete that are bridged by the concrete and lead to future settlement of the finer materials. For the best drainage, and the greatest ease and speed of construction, I would consider 3/8" pea gravel for most cases, except placement in a fine grained soil (you would need to place filter fabric between the soil/pea gravel interface for fine graiend soils).