Seven alumni from the University of Arizona's mining and geological engineering program competed in the alumni division, coming in second place. The competition commemorates the 91 miners who died in the 1972 Sunshine mine disaster and continues to honor all miners who have lost their lives while on the job.
Place concrete at a minimum thickness of 4 inches. Increasing the thickness from 4 inches to 5 inches will add approximately 20% to your concrete cost, but will also boost your driveway's load-carrying capacity nearly 50% , according to the Tennessee Concrete Association.lace concrete at a minimum thickness of 4 inches. Increasing the thickness from 4 inches to 5 inches will add approximately 20% to your concrete cost, but will also boost your driveway's load-carrying capacity nearly 50% , according to the Tennessee Concrete Association.
A gravel base, compacted in lifts will provide a good base for the concrete driveway. I would make the concrete six inches thick and use 4000 psi concrete with entrained air. We use #4 rebar, tied 18 inches on center for reinforcement and also add fibermesh to the concrete. The water/cement ratio of the concrete should be kept low (a 4 or 5 slump) for good strength and workability.