Concrete

CONCRETE (the origin of the Russian word "beton" is the Latin word "bitumen" (mountain resin) * EN: concrete, beton; DE: Beton; FR: beton; ES: hormigon; RU: бетон) is the artificial stone material, which is made of the mixture, which is composed of the binding substance with water, aggregate fillers, and (in certain cases) special additives.

The development and perfecting of the technology for the manufacturing of concrete are associated with the production of cement (within Russia since the start of the 18th century). Within the mine construction, tunnel building (see the "Sprayed concrete", "Waterproof concrete" articles), during the mastering of the petroleum and gas productive fields, during the construction of the petroleum and gas transport systems, there are most distributed the heavy concretes. The components of the heavy concrete are: sand, quartzous or feldspathic, less often of the dense limestone; gravel (or the crushed gravel) of granite and its varieties, carbonatic rocks, and sandstone. They present for these concretes the special requirements according to the granulometric composition and purity against the admixtures. There are used as the binding materials within the heavy concrete the Portland cement and its varieties (rapidly hardening, plasticized, hydrophobic, sulphate resistant), slag and pozzolana Portland cement, and also the special cements, namely, the non-shrinking, straining, and others.

Concrete distinguishes itself with high density (1800-2500 kilograms per cubic metre), low content of the bound water (for the extremely heavy concretes), increased strength against compression and tension, frost resistance, thermal conductivity, and technical viscosity (rigidity of the mixture). The strength of concrete is characterized by its grade mark (the temporary resistance to compression, which is measured in pascals). Within the USSR, the building norms and rules establish 10 major grade marks for the heavy concrete, namely, from 3.5 to 55 megapascals. The strength of concrete against the axial tension is less than the strength of concrete against the compression by approximately 10 times. Besides the strength indicators, there are presented for concrete the requirements for the mobility of the concrete mixture, its rigidity, and frost resistance. For the built structures, which are working under the pressure of water, there are presented the requirements for the water non-permeability, and for those structures, which are located under the influence of the sea water or other aggressive liquids and gases, there are presented the requirements for the resistance against corrosion. During the designing of the composition for the heavy concrete, there are taken into account the requirements for its strength against compression.