RU2758050C1 - Composition of lightweight self-compacting structural concrete (lkb) based on a cement matrix - Google Patents

Abstract

FIELD: building materials.

SUBSTANCE: invention relates to the building materials industry and can be used in the construction of buildings in civil, industrial construction and in the construction of structures for special purposes. Lightweight self-compacting structural concrete is obtained from a mixture containing, wt.%: mechanically activated Portland cement 15-25, polyfunctional modifier on a polycarboxylate base 1-2.5, rheologically active stone flour 10-25, water-retaining additive 0.003-0.02, micro- and nanosilica 1.5-7, glass ceramic foam granules 30-50, water - the rest.

EFFECT: obtaining lightweight self-compacting structural concrete of high strength, high frost resistance, low cost and low thermal conductivity.

1 cl, 2 tbl

Description

The invention relates to the building materials industry and can be used in the construction of buildings in civil, industrial construction and in the construction of structures for special purposes.

The purpose of the invention is to obtain lightweight self-compacting structural concrete (LKB) of high strength, high frost resistance, low cost and low thermal conductivity.

The composition for the manufacture of LKB contains mechanically activated Portland cement, glass ceramic foam granules, rheologically active stone flour, water-retaining additive, micro- and nanosilica, polyfunctional modifier on a polycarboxylate base, water, in the following ratio of components, wt%: mechanically activated Portland-functional modifier 15-25, polyfunctional -2.5, rheologically active stone flour 10-25, water-retaining additive 0.003-0.02, micro- and nanosilica 1.5-7, glass ceramic foam granules, 30-50, water - the rest.

The known composition of high-strength lightweight concrete (patent RU 2515450 C1, published: 05/10/2014) including, components wt.%: Portland cement 33.8-53.0; microsilica 4.77-13.8; stone flour 1.5-11.9; quartz sand 5.1-32.2; microspheres 4.3-19.27; plasticizer 0.3-0.48; water - the rest.

The disadvantage of this composite is its relatively low strength and high cost.

Also known is the composition of a heat-insulating and structural masonry mixture based on a lightweight aggregate (patent RU 2515631 C1, published: 05/20/2014), including components wt.%: Portland cement 15-20, quartz sand 22.308-39.196, hollow microspheres 1.310-9.978, water-retaining addition of 0.1% by weight of Portland cement, water - the rest.

The disadvantages of the masonry mixture are relatively low strength, with a high density, leading to a heavier structure.

The closest in technical essence to the claimed composition is the composition of high-strength lightweight fiber-reinforced concrete (patent RU 2548303 C1, published: 04/20/2015), containing components wt.%: Portland cement 34.5-52.7; microsilica (with an average particle size of 0.01-1 microns) 7.0-13.65; stone flour 1.5-11.9; quartz sand 5.1-31.3; microspheres 4.3-19.2; hyperplasticizer 0.3-0.48; fiber 0.3-1.5; water - the rest.

The disadvantages of this material is the high density of 1.4-1.79 g / cm ³ , which does not allow it to be classified as lightweight.

The proposed composite material is lightweight concrete with high thermal performance. This result is achieved by using a lightweight cuboid aggregate with many closed pores, which provide a high thermal insulation effect and a low density of the final product, as well as high adhesion to the binder. At low rates of density and thermal conductivity, concrete has high strength, which is achieved by creating a high-strength cement matrix in concrete due to rational packaging of components and the formation of strong chemical bonds. The offered concrete makes it possible to erect multi-storey buildings with high heat engineering and strength characteristics that meet modern requirements.

The technology of the proposed composition includes the following redistributions: mechanical activation of Portland cement together with a polyfunctional modifier based on polycarboxylate and micro- and nanosilica, dosage of dry components, water, mixing until a homogeneous cast mass is formed, product formation and exposure for 28 days until maximum strength is achieved.

Table 1 shows the compositions of the synthesized composites.

L

L

Were studied the physical and mechanical properties of the synthesized compositions, which are presented in table 2.

An analysis of the results obtained shows that all synthesized compositions have high compressive and bending strength, frost resistance and density corresponding to lightweight concrete in accordance with GOST 25820-2014.

Claims (1)

Lightweight self-compacting structural concrete obtained from a mixture containing mechanically activated Portland cement, a polyfunctional modifier based on a polycarboxylate base, water, micro- and nanosilica, rheologically active stone flour, a water-retaining additive, characterized in that it has the following ratio of components, wt%: 15 mechanically activated Portland cement -25, polyfunctional modifier 1-2.5, rheologically active stone flour 10-25, water-retaining additive 0.003-0.02, micro- and nanosilica 1.5-7, glass ceramic foam granules 30-50, water - the rest.