Gravel /ˈɡrævəl/ is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel is sub-categorized by the Udden-Wentworth scale into granular gravel (>2 to 4 mm or 0.079 to 0.16 in) and pebble gravel (>4 to 64 mm or 0.2 to 2.5 in). One cubic yard of gravel typically weighs about 3000 pounds (or a cubic metre is about 1,800 kilograms).
Gravel is an important commercial product, with a number of applications. Many roadways are surfaced with gravel, especially in rural areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over 400,000 km (250,000 mi) of gravel roads. Both sand and small gravel are also important for the manufacture of concrete.
Read more about Gravel: Geological Formation, Etymology, Types, Relationship To Plantlife
Famous quotes containing the word gravel:
“‘Lay me a green sod under my head,
And another at my feet;
And lay my bent bow at my side,
Which was my music sweet;
And make my grave of gravel and green,
Which is most right and meet.”
—Unknown. Robin Hood’s Death (l. 65–70)
“Let the new faces play what tricks they will
In the old rooms; night can outbalance day,
Our shadows rove the garden gravel still,
The living seem more shadowy than they.”
—William Butler Yeats (1865–1939)