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No. 56 Stone: Size, Weight and Gradation

No. 56 stone has a nominal size of 1 in to 3/8 in and weighs about 1.36 to 1.40 tons per cubic yard. Convert any amount below.

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No. 56 gradation

AASHTO M43 and ASTM D448 define No. 56 by how much passes each sieve. Ohio DOT lists its nominal size as 1 in to 3/8 in.

SieveOpeningPercent passing
1 1/2 in37.5 mm100
1 in25.0 mm90-100
3/4 in19.0 mm40-85
1/2 in12.5 mm10-40
3/8 in9.5 mm0-15
No. 44.75 mm0-5

AASHTO M43-05 (ASTM D448) limits as tabled by FHWA.

How much No. 56 weighs

FHWA measured the dry unit weight of No. 56 at 100.6 lb per cubic foot loose and 103.8 lb dense. That is 2,716 to 2,802 lb, or 1.36 to 1.40 tons, per cubic yard.

FHWA notes that sizes larger than No. 9 classify as poorly graded gravels: the stones are mostly one size, which leaves open space between them.

AmountLooseDense
1 cu yd1.36 tons1.40 tons
2 cu yd2.72 tons2.80 tons
5 cu yd6.79 tons7.00 tons
10 cu yd13.6 tons14.0 tons

Common questions

What size is No. 56 stone?

Its nominal size is 1 in to 3/8 in. The largest sieve it fully passes is 1 1/2 in (37.5 mm).

How much does a yard of No. 56 stone weigh?

FHWA's tests give 2,716 to 2,802 lb per cubic yard, from loose to dense.

How many yards are in a ton of No. 56 stone?

0.71 to 0.74 cubic yards.

Sources

  • https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/15034/003.cfm
  • https://spinternet.dot.state.oh.us/Divisions/ConstructionMgt/OnlineDocs/Specifications/2005CMS/700/703.htm