In the US there are approximately 1.3 million miles of gravel roads. Gravel is economic, durable and is the base for almost all road construction projects. Depending on the project, road bases can be up to 2.5 feet in depth of stone to form the roadway.
Did you know?
- Construction of a modern home requires about 400 tons of aggregate.
- A one mile stretch of a single lane road requires approximately 38,000 tons of gravel.
- California leads the nation in production of sand and gravel.
- In the United States, the production of sand and gravel in 1940 was about 200 million tons, whereas today it is around 300 billion tons.
- Typically, aggregates are sourced within 50 miles of the end user.
- The airport in Denver, CO used approximately 5 million tons of aggregates to construct its runway.
- The Grand Coulee Dam used approximately 17 million tons of stone to build its dam.
- As of 2006, the United States is the world’s leading producer and consumer of gravel.
Types of gravel include:
- Bank gravel: naturally deposited gravel intermixed with sand or clay. found in and next to rivers and streams. Also known as “bank run” or “river run”.
- Bench gravel: a bed of gravel located on the side of a valley above the present stream bottom, indicating the former location of the stream bed when it was at a higher level.
- Creek rock or river rock: this is generally rounded, semi-polished stones, potentially of a wide range of types, that are dredged or scooped from stream beds.. It is also often used as concrete aggregate and less often as a paving surface.
- Crushed stone: rock crushed and graded by screens and then mixed to a blend of stones and fines. It is widely used as a surfacing for roads and driveways, sometimes with tar applied over it. Crushed stone may be made from granite, limestone, dolostone, and other rocks.
- Fine gravel: gravel consisting of particles with a diameter of 2 to 8 mm.
- Stone dust: fine, crushed, gravel from the final stage of screen separation, such that the gravel is not separated out from fine dust particles.
- Lag gravel: a surface accumulation of coarse gravel produced by the removal of finer particles.
- Pay gravel: also known as “pay dirt”; a nickname for gravel with a high concentration of gold and other precious metals.
- Pea gravel: also known as “pea shingle” is gravel that consists of small, rounded stones used in concrete surfaces.