High-strength lightweight concrete has a high frost resistance and can reduce the cost of 1 m2 of housing in high-rise building 30%
High-strength lightweight concrete has the positive characteristics and benefits as compared to traditional light and heavy concretes. The most important feature of high-strength lightweight concrete and its distinctive party from the heavy concrete is almost 2 times smaller density. High-strength lightweight concrete has a high tensile strength under compression (grade M400 – M600), more than 2.5 times less thermal and thermal diffusivity.
The technology is awaiting funding!
High-strength lightweight concrete is a fine-grained concrete containing no coarse aggregate (gravel, etc.). The decrease in average density is achieved by spherical particles of micrometric size which is a carbon dioxide in a solid non-porous shell. In combination with selected special method of components of cement-a mineral component of concrete and special modifying additives of hollow filler forms both dense and durable concrete structure with a rich sealed porosity.
Developed high-strength lightweight concrete is classified as a structural material-use with high performance properties (see table below).
High-strength lightweight concrete has the positive characteristics and benefits as compared to traditional light and heavy concretes (see table). The most important feature of high-strength lightweight concrete and its distinctive party from the heavy concrete is almost 2 times lower density. This concrete has high tensile strength under compression (grade M400 M600… ). High-strength lightweight concrete is more than 2.5 times less thermal and thermal diffusivity.
Unlike lightweight concrete high-strength lightweight concrete has high strength, low water absorption and high frost resistance and uniformity of structure by volume. High-strength lightweight concrete has mark on frost resistance of not less than F300 (with a total porosity of 33.4%), which is not attainable for traditional cellular concretes. Currently in construction it is customary to combine heavy concrete, using it as a structural material with lightweight concrete for insulation of walling. The same properties of high strength lightweight concrete allow you to combine these functions in one material.
High-strength lightweight concrete does not contain coarse aggregate (crushed stone, etc.).
|Indicator:||High strength heavy concrete||Traditional lightweight concrete||High-strength lightweight concrete|
|Low average density||–||+||+|
|High specific strength||+||–||+|
|Low water absorption||+||–||+|
|Low thermal conductivity||–||+||+|
|High frost resistance||+||–||+|
Note: the “+” – presence of the specified quality; “–” – absence of specified quality.
High-strength lightweight concrete can be used:
– residential and public construction,
– for the erection of multi-storey and high-rise buildings and structures
– in the construction of rail and road bridges, flyovers, interchanges,
– in the manufacture of large-span of reinforced concrete products (farms, beams, girders,etc.)
– the unit of complex construction projects,
– high-strength lightweight concrete greatly expands the architectural possibilities of construction,
– special construction (nuclear industry, electricity,etc.)
– when building in a complex of soils (shoreline of rivers, lakes, seas),
– in areas with developed underground infrastructure (underground, tunnels),
– in a seismically unstable regions,
– in other areas of construction, where high demands for the operational properties of concrete, but there is a limit to the mass of products or designs, for example for the production of warm facades, the device of the balcony structures, the production of special raw materials-storage of spherical shape, etc.
The use of high-strength lightweight concrete in construction allows:
to reduce the weight of the building and increase the maximum number of storeys (up to 40%) low medium density
– reduce requirements for bases and foundations – to reduce the cost of the work on the “zero cycle” in 2-2,5 times,
– reduce the consumption of materials of construction due to the economy of concrete and metal reinforcement
– to improve the energy efficiency of the building during its operation (energy saving on heating),
– reduce the cost of transport and installation works through the use of less of the lifting equipment
– to reduce the cost of 1 m2 of housing in high-rise building by 30%
– the overall efficiency of the construction through the use of products from high-strength lightweight concrete is increased by 30-35%.
|Features:||Unit of measure:||Value:|
|The mobility diameter of RASPLAV cone||mm||at least 155|
|The average density||kg/m3||1300…1500|
|The Flexural strength||MPa||5,0 8,5…|
|Specific strength||MPa||30,0 50,0…|
|The ratio of fracture toughness||–||0,10 0,12…|
|The ratio of fracture toughness by the method of MIIT||–||0,27 0,42…|
|The modulus of elasticity||HPa||to 10.0|
|Poisson’s Ratio||–||to 0.12|
|Water absorption by weight||%||less than 1.0|
|Coefficient of thermal conductivity||W/(m∙K)||less than 0.60|
|The coefficient of thermal diffusivity||10-7 m2/s||less than 4.00|
|Specific heat (at T=25oC)||kJ/(kg∙K)||1,08 1,17…|
|The coefficient of water resistance||–||greater than 0.99|
High-strength lightweight concrete made of concrete mix of special composition that contains cement, filler, microspheres, quartz sand, plasticizer and water, additionally contains a mineral part consisting of the siliceous components of a particular composition and particle size. As a plasticizer used superplasticizer based on polycarboxylate, the effectiveness of which depends on the type, brand and concentration. High-strength lightweight concrete is a fine-grained concrete containing no coarse aggregate. The decrease in average density is achieved by introducing the spherical particles of the micrometer size which is a carbon dioxide in a solid non-porous shell. In combination with selected special method of components of cement-a mineral component of concrete and special modifying additives of hollow filler forms both dense and durable concrete structure with a rich sealed porosity.
For the preparation of high-strength lightweight concrete used Portland cement, corresponding to GOST 31108-2003, such as brand ПЦ500 D0. The mineral part, which includes quartz sand fractionated (FR. A 0.16…0.63 mm), corresponding to GOST 8739-93, and other siliceous components, fills intergranular voids of the filler, forming a dense structure. The filler used glass or aluminosilicate microspheres of the full, individual properties of which provide a reduction of the average density while maintaining high strength high strength lightweight concrete. Application of polycarboxylate superplasticizer from the producers of “Sika”, “Melflux” or “Odolit-T” allows to increase the mobility and reduce the water requirement.
The key component for obtaining high-strength lightweight concrete with desired physical and mechanical properties of nanoscale is a special additive used as a surface modifier of the filler particles. The functional necessity of its application due to the imperfection of the phase boundary microsphere/cement-mineral matrix. The using modifier allows you to increase adhesion in the contact zone of the hollow spherical filler and karkasoobrazuyuschego part of the high-strength lightweight concrete.
Quality products of high strength lightweight concrete will depend on prescription, so technological factors: the modes of preparation and laying of concrete mixtures, modes, steam curing, etc.
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