RU2711648C1 - Raw mixture for production of large-size silicate articles - Google Patents

Abstract

FIELD: construction.SUBSTANCE: invention relates to construction materials and can be used in making a construction mixture for producing silicate stones, blocks and slabs. Raw mixture for production of large-size silicate articles includes silica-lime binder with activity of 35–40 % and specific surface area of 5,000–6,000 cm/g, obtained by combined grinding of mixture of quartz sand and lime with activity of 70–80 % in ratio of 1:1, quartz sand with modulus of fineness 1.1–1.3, additionally contains crushed expanded clay sandof fraction 0–5 mm, obtained by crushing expanded clay gravel with fraction of 20–40 mm as maximum foamed with bulk density of 550–600 kg/m, fineness modulus 3.8, in following ratio of components, wt%: silica-lime binder 18, quartz sand 42–62, crushed expanded clay sand 20–40.EFFECT: high strength and crack resistance of raw material while maintaining strength of concrete and reducing its density.1 cl, 2 tbl

Description

The invention relates to the field of building materials and can be used as a raw material mixture for the production of silicate stones, blocks and plates.

The known composition of silicate brick from a mixture of quartz sand (92-94% by weight of the dry mixture) and quicklime or hydrated lime (6-8) [L. Havkin Technology of silicate brick / L.M. Khavkin. - M., 1982. - S. 108-114].

The disadvantage of this raw material mixture is that the products formed from it - “raw” have not high strength and crack resistance.

Known raw mix for the manufacture of silicate brick and wall materials, including lime, sand, additive, contains as an additive expanded clay gravel fraction 5-10 mm, in the following ratio of components, weight. %: lime 10.2-12.2, sand 39.8-47.8, expanded clay gravel 40-50 [RU 2243180 C2, MPK7 С04В 28/22, publ. 12/27/2004].

The disadvantage of this composition is that as one of the components it is proposed to use expanded clay gravel having a rounded shape of grains, which does not provide sufficient adhesion to the remaining components of the silicate mass, and, therefore, reduces the strength of the raw material and the finished product. This composition of the raw material mixture allows you to get silicate brick with the following properties: compressive strength - 100-125 kg / m ² , bulk density - 1572 kg / m ³ , thermal conductivity - 0.45 W / m

Known raw mix for the manufacture of silicate wall products containing, by weight. %: lime - 10.2-12.2, crushed foam glass - 20.0-60.0, quartz sand - 29.8-67.8. [RU 2303015 C1, C04B 28/22, publ. 07/20/2007].

This raw mix allows to obtain products with a low density of 972-1115 kg / m ³ and a thermal conductivity of 0.17-0.31, but reduces the compressive strength to 4.1-10.8 MPa.

Known raw mix containing in the waste production of expanded clay formed during the sorting of expanded clay gravel and representing a powdery material with a specific surface of 400 m ² / kg (expanded clay dust) [RU 2465235 C2, MPK7 C04B 28/20, publ. 10.27.2012].

Expanded clay dust is introduced instead of part of the sand in the following ratio of components, wt. %: lime 6; silica sand 69; expanded clay dust 25.

This composition allows you to get silicate brick with high physical and mechanical properties, but does not improve the crack resistance of the "raw".

Closest to the claimed is a raw material mixture for the manufacture of silicate brick and wall materials, including: lime-silica binder with an activity of 35-40% and a specific surface of 5000-6000 cm ² / g, obtained by co-grinding a mixture of silica sand and lime with an activity of 70 -80%) in a ratio of 1: 1, quartz sand with a particle size module of 1.1-1.3 and crushed aerated concrete with a density of 500-600 kg / m ³ fractions of 0-5 mm with a particle size of 2.5 in the following ratio of components, wt . %: lime-silica binder 18, quartz sand 33-49, crushed aerated concrete 33-49 [RU 2661173 C2, С04В 28/18, С04В 18/16, С04В 2111/40, publ. 07/12/2018].

This composition allows you to get silicate brick with high physical and mechanical properties, but does not improve the crack resistance of the "raw".

The objective of the invention is to increase the strength and crack resistance of the "raw" while maintaining the strength of silicate concrete, while reducing its density, which will not only improve the operational properties of the finished product, but will also significantly reduce the percentage of defects in the manufacture of products.

Raw mix for the production of large-scale silicate products, including a lime-silica binder (18%) with an activity of 35-40% and a specific surface of 5000-6000 cm ² / g, obtained by co-grinding a mixture of silica sand and lime, with an activity of 70-80% in 1: 1 ratio, quartz sand with a fineness modulus of 1.1-1.3 (42-62%) additionally contains crushed expanded clay sand with a density of 550-600 kg / m ³ fractions of 0-5 mm with a fineness modulus of 3.8 (20- 40%). The lime-silica binder has an activity of 35-40%, a specific surface area of 5000-6000 cm ² / g and is a mixture of silica sand and lime obtained by joint grinding with an activity of 70-80%) in a ratio of 1: 1. Crushed expanded clay sand is obtained by crushing expanded clay gravel fractions of 20-40 mm, as maximally expanded and has the following characteristics: bulk density 550-600 kg / m ³ , particle size modulus M _k = 3.8.

The causal relationship between the composition of the raw mix and the specified technical result is as follows:

- crushed expanded clay sand included in the raw material mixture has a low density, which leads to a decrease in the density of finished products;

- during the crushing process, microdefects are formed on the fracture surface of expanded clay grains, which play the role of active centers that can enter into chemical interaction with calcium hydroxide during autoclaving, which compensates for the decrease in the strength of silicate concrete from the introduction of a less durable than silicate concrete material - expanded clay ;

- due to the rough surface and the angular shape of the expanded clay grains obtained in the crushing process, the adhesion between the particles of the silicate mass improves, which leads to an increase in the strength and crack resistance of the raw material. The number of cracks formed in the "raw" during molding and transportation to the autoclaves is significantly reduced, which is especially noticeable in the production of large-format silicate products.

The claimed raw material mixture is prepared as follows: quartz sand, crushed expanded clay sand and lime-siliceous binder are mixed in the indicated proportions in a single-shaft continuous mixer, then the resulting mixture is humidified on a conveyor belt to the required humidity (9-12%) and fed to the silo, where aged for 1-2 hours to extinguish lime. Products are formed on the presses from the resulting mass, which are called “raw” before autoclaving. Then they are subjected to autoclaving at a pressure of 0.9 MPa and a temperature of 176 ° C, according to the regime: 1.5-7-1.5 hours.

The composition of the raw mix,% by weight are shown in table 1

Table 2 shows the characteristics of silicate concrete based on the inventive raw mix.

When the content of crushed expanded clay sand in the composition of the raw material mixture is less than 20%, the required increase in the strength of the “raw material” is not achieved.

When the content of crushed expanded clay sand in the composition of the raw material mixture is more than 40%, the strength of silicate concrete is reduced.

Claims (2)

Raw mix for the production of large-scale silicate products, including a lime-silica binder with an activity of 35-40% and a specific surface of 5000-6000 cm ² / g, obtained by co-grinding a mixture of quartz sand and lime with an activity of 70-80% in a ratio of 1: 1, quartz sand with a particle size of 1.1-1.3, characterized in that it additionally contains crushed expanded clay sand of a fraction of 0-5 mm obtained by crushing expanded clay gravel of a fraction of 20-40 mm as maximally expanded with a bulk density of 550-600 kg / m ³ , particle size modulus 3.8, in the following ratio of components, mass. %: Lime silica binder 18 Quartz sand 42-62 Crushed expanded clay sand 20-40