Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.
As the term is used by geologists, sand particles range in diameter from 0.0625 (or 1/16 mm, or 62.5 micrometers) to 2 millimeters. An individual particle in this range size is termed a sand grain. The next smaller size class in geology is silt: particles smaller than 0.0625 mm down to 0.004 mm in diameter. The next larger size class above sand is gravel, with particles ranging from 2 mm up to 64 mm (see particle size for standards in use). Sand feels gritty when rubbed between the fingers (silt, by comparison, feels like flour).
ISO 14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In USA, sand is commonly divided into five sub-categories based on size: very fine sand (1/16 – 1/8 mm diameter), fine sand (1/8 mm – 1/4 mm), medium sand (1/4 mm – 1/2 mm), coarse sand (1/2 mm – 1 mm), and very coarse sand (1 mm – 2 mm). These sizes are based on the Krumbein phi scale, where size in Φ = -log base 2 of size in mm. On this scale, for sand the value of Φ varies from -1 to +4, with the divisions between sub-categories at whole numbers.
In: industrial rocks and minerals · Tagged with: concrete component, sand
Crushed Stone
Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from gravel which is produced by natural processes of weathering and erosion, and typically has a more rounded shape. Angular crushed stone is the key material for macadam road construction which depends on the interlocking of the individual stones’ angular faces for its strength. Crushed natural stone is also used similarly without a binder for riprap, railroad track ballast, and filter stone. It may also be used with a binder in a composite material such as concrete, tarmac, or asphalt concrete.
Crushed stone is one of the most accessible natural resources, and is a major basic raw material used by construction, agriculture, and other industries. Despite the low value of its basic products, the crushed stone industry is a major contributor to and an indicator of the economic well-being of a nation. The demand for crushed stone is determined mostly by the level of construction activity, and, therefore, the demand for construction materials.
Stone resources of the world are very large. High-purity limestone and dolomite suitable for specialty uses are limited in many geographic areas. Crushed stone substitutes for roadbuilding include sand and gravel, and slag. Substitutes for crushed stone used as construction aggregates include sand and gravel, iron and steel slag, sintered or expanded clay or shale, and perlite or vermiculite.
In: industrial rocks and minerals · Tagged with: Construction aggregate, crushed stone