RDrancher
Veteran Member
Have you considered a 3 pt hitch dump box for your tractor? The 10 cubic foot size will carry 400 to 500 lb. without difficulty. The 30 cubic foot size would handle all your tractor can lift. It would be cheap, relatively quick, and wouldn't strain the geometry of your loader like an oversized bucket.
Just Google "3 pt hitch dump box" to locate a supplier.
Using the minimum weight of 4050lbs per cubic yard of wet concrete, 40 cubic yards would require approximately 324 trips with a 500lb load.