Road base calculator for Alaska

A lane measuring 100 feet long by 10 feet wide at 6 inches compacted calls for about 31 tons of road base. Quantities build fast on lanes, and free delivery matters when moving 30 tons can rival the stone cost. Road base uses graded crushed stone and fines, weighing about 3,000 lb per cubic yard, and compacts into a dense layer beneath driveways, roads, and equipment yards. Use the same calculation for recycled crushed concrete base when the spec permits it.

Lane calculations

1. Use centerline length with the average width for a lane. For a pad, multiply its length and width.
2. Light residential use calls for 4 inches compacted; use 6 for routine traffic and delivery trucks, and 8-12 beneath equipment or on soft ground.
3. Take cubic feet / 27 for yards, then x 1.5 for tons, with +10% included for compaction.

Coverage and lane estimates

Building a lane for the next winter

• Remove organics before placing stone. If base goes over topsoil, mud will pump through it regardless of how thick the layer is.
• Put woven geotextile down before stone where the subgrade is wet or soft. On muskeg, it helps keep the base separated from the ground below.
• Place and roll each lift at 4 inches or less before adding another lift.
• Use a 2-3% crown from the centerline to each edge, keeping rain from entering the base.
• For a clean driving surface with less dust, finish with #57 or driveway gravel.
• Because 20-plus tons is difficult to spread by hand over a week, include a tractor box blade or skid steer in the budget for afternoon spreading.

Example: a 100-foot farm lane

At one hundred by ten feet and 6 inches deep: 1,000 x 0.5 = 500 cubic feet = 18.5 cubic yards, or about 28 tons, with 30-31 after the allowance. Plan for two tandem loads and place them at two points along the run, rather than leaving one pile at the gate. This helps keep spreading moving downhill instead of requiring material to be hauled uphill.

Pads for containers, RVs, and equipment

Use the lane calculation for pads, but choose depth for axle loads rather than the calendar. A 12 x 40 RV pad at 6 inches compacted needs about 12 tons. At 8 inches, a 20 x 40 equipment yard requires 27. Since shipping containers focus weight on four corners, use a full 8 inches plus fabric under container pads, even where the ground seems decent, to limit corner settlement by spring.

Using crushed concrete for road base

Virgin road base and recycled concrete base both compact for load support, and recycled material can cost less. Check local specifications before changing materials, since some call for virgin aggregate. It can be used on private lanes and pads. Figure it the same way: 1.5 tons per yard, with the same lifts and crown.

Road base by ton and lane

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