Gravelsized

Gravelsized, or gravel-sized, is a term used to describe particulate material whose particles fall within the gravel size range. In many classification schemes, gravel-sized material consists of particles larger than about 4.75 millimeters and up to about 64 millimeters in diameter, with some standards allowing sizes up to 75–76 millimeters. The exact bounds vary by system, but the concept distinguishes gravel from finer fractions such as sand and silt.

Gravel-sized material can occur naturally, formed by rivers, glaciers, or coastal processes, and may also be produced by crushing rock. Grains are commonly rounded or subrounded when transported, though crushed gravels can be angular. Mineral composition varies widely, reflecting the source rock, with common varieties including quartz-rich and carbonate gravels.

In terms of physical properties, gravelsized material typically exhibits high permeability and good drainage compared with finer soils. It is relatively resistant to compaction, depending on particle shape and the amount of fines present. Clean gravels have few fines, while gravels with fines may show reduced drainage and different compaction behavior.

Classification schemes often distinguish well-graded gravels (GW) from poorly graded gravels (GP); well-graded gravels contain a broad range of particle sizes that interlock and reduce voids, whereas poorly graded gravels are more uniform in size. Applications of gravelsized materials include construction aggregates for concrete and asphalt, subbases or drainage layers in roads and foundations, ballast in railway tracks, and various landscaping or filtration uses where rapid water movement is desired.