What are building materials
Aggregates (crushed stone, gravel and sand) are materials of mineral origin used in a natural state for construction purposes without extracting certain minerals from them.
Crushed stone is a product obtained as a result of rock materials crushing. This product is produced by processing rock materials extracted from a quarry. After crushing and sieving (using the method of mechanical grain sizing of granular materials), these rock materials are processed to fractions of crushed stone.
The main properties of crushed stone produced from the natural stone materials are the following:high strength; cold-resistance; flakiness; true, average and bulk density; water absorption and water saturation rate; grain composition and shape; natural radionuclide activity (radioactivity) rate.
Gravel is a nonmetallic construction material consisting of rounded grains with smooth surface of 5 to 70 mm in size formed as a result of natural rock destruction processes. The quality of gravel is characterized by its grain size and shape, strength, content of soft rock grains, fine and clay additions, petrographic characteristic, density, porosity, cavitation and water saturation rates. By its origin, gravel is distinguished into rock (granitic), river (sea) and artificial (keramzite) gravels. As a construction material, gravel has a number of positive and negative properties. The positive properties of gravel are low price and possibility of quick laying. The negative properties of gravel include: the need to level and fix gravel, impossibility to cover inclined surfaces with gravel. Gravel is used as an aggregate for light concrete production, for heat/acoustic insulation filling, for construction and landscaping works, road construction and site improvement, for floristic and aquariumistics and as a filler for water well filter systems and other sources of clear water, and also for roof armoring.
Quarry sand can be used for a variety of applications, to start from masonry and plaster works to heavy concrete production, site improvement, road works and backfilling of foundations. Different quarries produce different type of sands for various types of work, but at all times they must provide high quality of their product required for construction works.
River sand is used as an aggregate for production of heavy, light, fine-grained, porous and silicate concretes, mortars and dry mix preparation. It is used for such construction works as masonry, screed (rarer plaster works), and as an aggregate for concrete trim and staining compounds. In certain cases, it is used for production of reinforced-concrete items, in particular, for paving slabs, arrangement of road beds and paving. River sand contains minimum additions of clay and has a considerably larger filtration coefficient as compared comparison with the quarry or ungraded sand.
Concrete is an artificial rock material produced by hardening a specially prepared mixture consisting of a binding material (cement), coarse and fine aggregates and water. Where required, special additives can be added into the concrete mixture to improve its processing and structural characteristics. Concrete mixture composition must exhibit all required properties by the given time, such as strength, cold resistance, water impermeability etc. Concrete is the main construction material used in all fields of construction. The technical and economic advantages of concrete and reinforced concrete include: low expenses on fabrication of structural components due to the use of local raw materials; possibility of using it in various precast and cast-in-situ structures for numerous applications, mechanized and automated processes of concrete mixing and structures production. With proper processing, the concrete mixture allows constructing structures of optimum shapes as viewed from the standpoint of structural mechanics and architecture. Concrete is durable and fireproof, its density, strength and other characteristics can be changed over the wide range. By aggregate types, concretes are divided into dense aggregate, porous concretes, concrete with special aggregates meeting the special requirements, such as radiation protection, heat resistance and chemical resistance etc. Local rock materials, such as sand, gravel, crushed stone and industrial by-products, are used as aggregates. When designing concrete and reinforced concrete structures, all required characteristics should be specified, such as class (grade) of concrete strength, cold-resistance and waterproofing grades. The most important technical and economic requirement to concrete is its homogeneous consistency.