Product Code Database
Gravel () is a loose aggregation of . Gravel occurs naturally on Earth as a result of sedimentation and erosion geological processes; it is also produced in large quantities commercially as crushed stone.
Gravel is classified by grain size range and includes size classes from granule- to boulder-sized fragments. In the grain size gravel is categorized into granular gravel () and pebble gravel (). ISO 14688 grades gravels as fine, medium, and coarse, with ranges for fine and for coarse. One cubic metre of gravel typically weighs about , or one cubic yard weighs about .
Gravel is an important commercial product, with a number of applications. Almost half of all gravel production is used as aggregate for concrete. Much of the rest is used for road construction, either in the road base or as the road surface (with or without bitumen or other binders.) Naturally occurring porous gravel deposits have a high hydraulic conductivity, making them important .
The technical definition of gravel varies by region and by area of application. Many geologists define gravel simply as loose rounded rock particles over in diameter, without specifying an upper size limit.
The U.S. Department of Agriculture and the Soil Science Society of America define gravel as particles from in size, while the German scale (Atterburg) defines gravel as particles from in size.
The bulk density of gravel varies from .
Gravel is deposited as gravel blankets or bars in stream channels; in alluvial fans; in near-shore marine settings, where the gravel is supplied by streams or erosion along the coast; and in the deltas of swift-flowing streams. The upper Mississippi embayment contains extensive chert gravels thought to have their origin less than from the periphery of the embayment.
It has been suggested that wind-formed (aeolian) gravel "megaripples" in Argentina have counterparts on the planet Mars.
It is estimated that almost half of construction sand and gravel is used as aggregate for concrete. Other important uses include in road construction, as road base or in blacktop; as construction fill; and in myriad minor uses.
Gravel is widely and plentifully distributed, mostly as river deposits, river flood plains, and glacial deposits, so that environmental considerations and quality dictate whether alternatives, such as crushed stone, are more economical. Crushed stone is already displacing natural gravel in the eastern United States, and recycled gravel is also becoming increasingly important.
(1996). 9780716724384, W.H. Freeman. ISBN 9780716724384 (2026). 9780131547285, Pearson Prentice Hall. ISBN 9780131547285 (2026). 9780199653065, Oxford University Press. ISBN 9780199653065 Gravel is sometimes distinguished from rubble, which is loose rock particles in the same size range but angular in shape. (2026). 9780716739050, W.H. Freeman. ISBN 9780716739050 The Udden-Wentworth scale, widely used by geologists in the US, defines granular gravel as particles with a size from and pebble gravel as particles with a size from . This corresponds to all particles with sizes between coarse sand and cobbles.
(1980). 9780136427100, Prentice-Hall. ISBN 9780136427100 The U.S. Army Corps of Engineers defines gravel as particles under in size that are retained by a number 4 mesh, which has a mesh spacing of . (1980). 9780136427100, Prentice-Hall. ISBN 9780136427100 (1997). 9780922152346, American Geological Institute. ISBN 9780922152346 ISO 14688 for soil engineering grades gravels as fine, medium, and coarse with ranges 2 mm to 6.3 mm to 20 mm to 63 mm.
(1992). 9780873351003, Society for mining, metallurgy and exploration (SME). ISBN 9780873351003 Natural gravel has a high hydraulic conductivity, sometimes reaching above 1 cm/s.
Origin
Most gravel is derived from disintegration of bedrock as it Weathering. Quartz is the most common mineral found in gravel, as it is hard, chemically inert, and lacks along which the rock easily splits. Most gravel particles consist of multiple mineral grains, since few rocks have mineral grains coarser than about in size. Exceptions include quartz veins, , deep , and high-grade metamorphic rock. The rock fragments are rapidly rounded as they are transported by , often within a few tens of kilometers of their source outcrops.
Production and uses
Gravel is a major basic raw material in construction. Sand is not usually distinguished from gravel in official statistics, but crushed stone is treated as a separate category. In 2020, sand and gravel together made up 23% of all industrial mineral production in the U.S., with a total value of about $12.6 billion. Some 960 million tons of construction sand and gravel were produced. This greatly exceeds production of industrial sand and gravel (68 million tons), which is mostly sand rather than gravel.
Etymology
The word gravel comes from the Old French graveleCollins English Dictionary – Complete & Unabridged 11th Edition. Retrieved 30 August 2012 from CollinsDictionary.com website:http://www.collinsdictionary.com/dictionary/english/gravel or gravelle.Gravel, n., Oxford English Dictionary Second Edition on CD-ROM (v. 4.0) © Oxford University Press 2009
Types
Different varieties of gravel are distinguished by their composition, origin, and use cases. Types of gravel include:
Relationship to plant life
In locales where gravelly soil is predominant, plant life is generally more sparse.C.Michael Hogan. 2010. Abiotic factor. Encyclopedia of Earth. eds Emily Monosson and C. Cleveland. National Council for Science and the Environment . Washington DC This is due to the inferior ability of gravels to retain moisture, as well as the corresponding paucity of mineral nutrients, since finer soils that contain such minerals are present in smaller amounts.
In the geologic record
containing over 30% gravel that become lithification into solid rock are termed conglomerate. Conglomerates are widely distributed in sedimentary rock of all ages, but usually as a minor component, making up less than 1% of all sedimentary rock. Alluvial fans likely contain the largest accumulations of gravel in the geologic record. (2026). 9781405177832, Wiley-Blackwell. ISBN 9781405177832 These include conglomerates of the Triassic basins of eastern North America and the New Red Sandstone of south Devon.
See also
External links
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