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.
Once the site is ready, paving with asphalt follows. In many cases a 4-inch thickness may be adequate, but 5 or even 6 inches of full-depth asphalt will assure you of a stronger, stable driveway under a wider range of climate and loads. As an option, some contractors use 6 to 8 inches of compacted aggregate, or gravel, as a base for 3 inches of asphalt pavement. We recommend full-depth asphalt for driveways, says Kent Hansen, NAPA Director of Engineering. We calculate that asphalt can replace aggregate on a ratio of 1:3 in thickness. That is, 1 inch of asphalt pavement is equivalent to 3 inches of aggregate base.. However, an aggregate base still may be required to ensure a solid foundation for construction equipment on weaker subgrades.