Fraction is an important parameter in the selection of crushed stone and sand for construction

Loose or lumpy basic building materials in accordance with technical standards vary in size. When sorting materials by sieving through a sieve system, a fraction is determined. This means that the rubble or sand is divided according to the size of the particles or grains.

What factions are rubble?

The most common material in any construction is crushed stone. It is used for the construction of road cushions, blind areas, it enters the component into the concrete mixture. In each specific case, a specific size of crushed stone with its inherent physical characteristics is used. GOST stipulates that the fraction is the size of the physical unit of the stone, which fits within the established framework. There are two basic standard fractions (5-25 mm and 25-60 mm) that are used in construction. Modern equipment, however, makes it possible to screen out crushed stone in narrower values that are required for individual tasks, from the smallest (up to 1 centimeter) to the very large ones (12 to 30 centimeters).

Why do you need rubble?

Industrial production of concrete and reinforced concrete structures, as well as asphalt, involves the use of a fine fraction of crushed stone - from 5 to 20 mm. When installing tram tracks, railroad embankments, pillows for highways, more commonly used crushed stone (fractions 20/65 or 40/70 mm).

Large fractions are suitable for the construction of foundations, and in landscape works the largest stone is used - up to 30 cm.

Thus, the fraction is the size of the rubble that has been selected, prepared and tested in accordance with the requirements of GOST.

A common indicator for all fractions of a stone is considered to be the cuboid shape of the particles, which is achieved in the process of crushing.

Sand fractions and applications

Sand is used not only in construction, but also in industry, for example, for the manufacture of insulation or glass, the production of glue and dry mixes, putties, self-leveling floors, foundries, and sandblasting. To avoid problems with the choice of raw materials, you need to know its characteristics and purchase exactly that sand, which is necessary for a particular type of work.

Classify the sand, depending on the origin and method of treatment. It can be river, sea, quarry, quartz, perlite, and for each species there is a normative document. For example, GOST standards regulating the parameters of raw materials used in testing cement, distinguish between polifraction and monofractional quartz sand. The reference is sand from the deposits of the Czech Chalkland.

A common characteristic for sands of different origins is the size modulus (fraction) - this is when most of the particles are about the same size. So, sand is very large, consisting of grains up to 0.5 cm in diameter. Large - 2,5-3,5 mm, medium - 1-2,5 mm, small - 0,5 to 1,5 mm, and smaller grains belong to the category of "fine sand".

River sand - an ideal raw material for the production of concrete products, and a career - for mixing masonry or plaster solutions, foundation work. Quartz sand is mainly used for the production of shingles and polymer products, faience and porcelain, for water filtration, welding materials and foundry molds.