Surface Course Tons Versus Binder Course Tons

A two-lift driveway might use about two inches of coarser binder and about 1.5 inches of finer surface. Add the thicknesses, or add the tons from each lift. On 1,000 square feet that planning total is about 21 tons. The plant ticket is the real weight.

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Two lines on the quote are both asphalt

Binder is the lower, coarser, structural layer. Surface is the tighter mix you drive on. A quote that lists both is not double-counting a single mat unless someone later adds the total a second time. A common planning split is 2 inches of binder and 1.5 inches of surface. The compacted total is 3.5 inches. You can add the thicknesses first and convert once, or convert each lift and add the tons. The formula needs that compacted thickness either way. Tons for each lift equal area times that lift's inches times 145, divided by 24,000. This is a planning estimate at 145 pounds per cubic foot. The plant ticket for each load is the real weight.

Add the lifts on 1,000 square feet

Two inches on 1,000 square feet is 1,000 times 2 times 145 divided by 24,000, about 12.1 tons. An inch and a half on the same area is about 9.1 tons. Add 12.1 and 9.1 and you get about 21.2 tons. The single calculation at 3.5 inches is 1,000 times 3.5 times 145 divided by 24,000, which equals 21.145, about 21.1 tons. The tenth is rounding, not extra mix. They are the same volume. If your area is half of that, half the tons. If the quote uses 2 inches and 1 inch instead, add those depths and ignore the 3.5-inch example. Do not add 21 tons on top of the two lift tons. That would order the driveway twice.

What the split does not change

The split changes texture and how the crew places the work. It does not change the fact that both layers are hot mix and both belong in the tonnage. Surface mix is what you see and maintain. Binder is there to build thickness under it. Neither line item is gravel. Stone under the binder is a separate order, often planned near 1.4 tons per cubic yard, and the quarry ticket is the real weight for that stone. Ask the plant which mix is shipping for each lift if the quote only says binder and surface. Do not invent a price from the two tonnage lines. Quantity and money are different conversations, and the scale tickets are the quantities you received.

A practical sequence

Add the binder thickness and the surface thickness before you convert, or convert each and add.
On 1,000 square feet, plan about 12.1 tons for two inches and about 9.1 tons for 1.5 inches.
Do not add the combined total a second time on top of the lifts.
Treat the sum as a planning estimate and keep each plant ticket as the real weight.

The mistake to skip

Counting only the surface course and forgetting the binder tons on the line above it.

Questions people ask

Do binder and surface use the same ton formula?

Yes. Both are compacted hot mix in this planning method, at 145 pounds per cubic foot, unless the plant gives a different density for one of them. Calculate each thickness, then add the tons. The total compacted depth is what the volume needs. Tickets from the plant are the real weights.

Is the surface course the only layer I drive on?

The surface is the tighter mix on top, and it is the layer you see. The binder under it is still part of the pavement thickness and still part of the tons. Leaving it out of the order understates the job by the whole lower lift.

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