Sand

Summary

Sand is finely divided mineral particles 0.074 to 4.75 mm in the Unified Soil Classification System, usually silica (quartz). It is the fine aggregate in concrete and mortar, and angular sharp sand is preferred over rounded desert sand.

Cols

Image

Fine aggregate: sand used in concrete and mortar
Sharp sand: angular sand preferred for concrete
USCS sand: 50 percent or more of the coarse fraction passes the No. 4 sieve; groups SW, SP, SM, SC
Geological sand: 0.0625 to 2 mm
Silica: SiO₂, usually as quartz

History and demand

Sourcing

China, Indonesia, Malaysia, and Cambodia ban sand exports; UNEP recommended banning beach extraction
River sand, the main construction source, has depleted many small rivers; dredging harms marine life and fisheries

Demand trend

Estimates of annual use of sand and gravel vary: about 40 billion tons ($70 billion), 9.55 billion tons in 2017 ($99.5 billion), and 50 billion tons per year in 2022
Non-renewable on human timescales

Composition and production

Raw materials

Silica (quartz) in most inland and non-tropical coastal sand; calcium carbonate from coral and shells in the tropics; calcium sulfate (gypsum) at White Sands
Magnetite, feldspar, garnet, and olivine affect color

Grades and types

Class (US)	Size
Very fine	1/16 to 1/8 mm
Fine	1/8 to 1/4 mm
Medium	1/4 to 1/2 mm
Coarse	1/2 to 1 mm
Very coarse	1 to 2 mm

Standards

Test methods

ASTM D2487: soil classification (Unified Soil Classification System)

Uses in buildings

Building elements

Terrazzo: sand cushion systems
CMU Walls, Brick Veneer Walls: mortar and grout
Pipe Bedding: trench bedding
Sand is also the fine aggregate in every concrete element; see Concrete

Pros and cons

Pros

Widely available
Silica sand is the principal component of common glass
Angular sand bonds well in concrete

Cons

Rounded desert sand is unsuitable for concrete
Sand mining depletes rivers and harms marine life
Silica dust from sandblasting is a serious inhalation hazard

Sustainability

Health

Generally non-toxic, but crystalline silica dust from sandblasting is a serious inhalation hazard; sandblasting sand carries respirator warnings

Manufacturing and cost

Main manufacturers and suppliers

Trade association: National Stone, Sand and Gravel Association.

Sources

Wikipedia: Sand, https://en.wikipedia.org/wiki/Sand
Wikipedia: Unified Soil Classification System, https://en.wikipedia.org/wiki/Unified_Soil_Classification_System
Wikimedia Commons: 00065 sand collage.jpg, photo by Siim Sepp (Sandatlas) (CC BY-SA 3.0), https://commons.wikimedia.org/wiki/File:00065_sand_collage.jpg