RU2348588C2 - Dry construction mixture - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: dry construction mixture contains cement, mineral filler with particles size less than 5 mm including sand and zeolite - containing rock in a 1:1 ratio, given the following components ratio, in wt %: cement - 18.75-25. sand - 37.5-40.625, zeolite - containing rock - 37.5-40.625.

EFFECT: enhanced strength, widened raw material base, cost reduction.

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Description

The invention relates to the field of building materials, and more specifically to dry building mixes, and can be used in the manufacture of plastering and masonry work.

World and domestic experience in the use of dry mixtures has shown their high efficiency and advantages compared to traditional methods of work. Dry building mixes are fine-grained, carefully mixed compositions of dry components of a rational composition, which include binders, fractionated aggregates of strictly defined quality, finely dispersed mineral components, chemical and polymer additives. (Bazhenov Yu.M. Concrete technology: a textbook. / Yu.M. Bazhenov. - M.: DIA publishing house, 2002. - P. 406)

Known dry mix for the preparation of mortar, including lime-cement binder 7-29%, sand 71-93%, organic additives 0-0.2%. (RU, 2196752 C2, priority date 12/08/2000, publication date 1/20/2003, MV Merkuryev).

A disadvantage of the known dry mix is that the following operations are necessary for preparation: fractionation of the aggregate, the introduction of additives, which will increase the duration of the dry mix preparation process.

As a prototype, a dry building mixture for masonry and plastering works was adopted, including cement, sand and a complex additive containing C-3 plasticizer powder, calcium or zinc stearate in the following ratio of components, wt.%: Cement 14.2-49.9, sand 49.6-85.6, C-3 0.04-0.50, calcium or zinc stearate 0.10-0.3 (RU, 2214376 C1, priority date 06/10/2002, publication date 10/20/2003, author Rosenthal N.K. et al., Prototype).

The disadvantage of the prototype is that the solutions have low strength, which will affect the durability and reduced performance, as well as increased cost due to the use of complex additives in the mixture.

The objective of the invention is to increase strength, expand the raw material base, reduce costs.

To solve the problem in a dry building mixture containing cement, a mineral aggregate comprising sand, according to the invention, the mineral aggregate further comprises a zeolite-containing rock in the ratio of sand and zeolite-containing rock 1: 1 with a particle size of not more than 5 mm in the following ratio of components, in wt. .%:

Cement 18.75-25 Sand 37.5-40.625 Zeolite-bearing rock 37.5-40.625

The proposed dry construction mixture differs from the prototype in that the zeolite-containing rock is a structure-forming component due to the binding of Portland cement minerals to amorphous silica and alumina, which leads to an increase in the strength of mortar samples, and also increases water demand, since the zeolite-containing rock has higher adsorption properties. At the same time, the setting time of the mixed composition based on zeolite-containing rocks is reduced. This is due to the fact that, firstly, the content of alkaline oxides in the zeolite-containing rock is increased, which accelerate the hydration of the complex binder, on the other hand, the active alumina of the zeolite binds sulfate ions and lime released during hydration of clinker minerals into calcium hydrosulfoaluminates. Moreover, their formation does not occur on grains of cement clinker, but on zeolite particles or in pore space. The release of silica from the decomposing zeolite lattice is facilitated both by binding alumina from the alternating alumina-silicon skeleton and by attacking Si-O-Si bonds by Ca ^{2+ ions} not only from the surface of the formed “silica sponge”, but also through the porous system of zeolite channels.

The introduction of zeolite-containing rock into the mortar leads to an increase in adhesion to the plastered surface, both brick and concrete. At the same time, the adhesion to the brick surface is earthenly higher in comparison with the concrete surface. This is because the brick has a higher porosity, and unhydrated water from the solution goes into the pores of the brick, as a result, the solution has a lower porosity, due to which it becomes more dense and durable. When adhering to the surface of concrete, almost all water remains in the solution, since concrete has a porosity much lower than that of brick, pores are formed in the solution, as a result, the adhesion strength decreases. The results are presented in the table.

In addition, the use of a zeolite-containing rock in the composition of a dry mortar reduces salt formation by 29%. This is due to the fact that the zeolite-containing rock is a structure-forming binder due to the activation of hydration processes, since the zeolite plays the role of growing crystallization centers under conditions when these crystals are washed by alkaline aluminosilicate solution.

The use of composite binder on accessible local raw materials is one of the areas of resource and energy saving in the technology of construction production, which leads to economic efficiency and technological feasibility of preparing the inventive dry building mix with improved performance properties.

To prepare a dry building mixture, Portland cement M400 D 20 is used in accordance with GOST 10178-85; mineral aggregate - quartz sand of the Terentyevsky deposit with Mkr = 0.68 according to GOST 873693, zeolite-containing rock of the Sakhaptinskoye deposit. The mineral composition of the zeolite-containing rock of the Sakhaptinsky deposit, according to x-ray phase analysis, is represented by zeolite (heylandite and clinoptilolite), quartz, plagioclases, clay minerals. The chemical composition of the zeolite-containing rock, wt.%: SiO ₂ 66.01, TiO ₂ 0.34, Al ₂ O ₃ 12.51, Fe ₂ O ₃ 2.36, CaO 2.27, MgO 1.66, Na ₂ O 1.04, K ₂ O 3.24.

The proposed mixture can be used for the preparation of plaster and masonry mortar mixtures.

Indicator Prototype Cement 49.6;
C-3 - 0.2; Calcium Stearate 0.3;
H / C 0.6 Suggested formulations Cement 18.75;
Sand 40.625; Zeolite-containing rock 40.625;
W / D 1.64 Cement 22.65; Sand 38.7;
Zeolite-containing rock 38.7;
H / C 1.35 Cement 25; Sand 37.5
Zeolite-bearing rock) 37.5;
W / D 1.22 Bulk density kg / m ³ 1500 1190 1215 1250 Water retention capacity,% 98.0 98.0 98.0 98.0 Compressive strength, MPa 10 17,2 16,0 15.4 Frost resistance, brand not lower than F 50 more than F 50 more than F 50 more than F 50 The presence of efflorescence absent absent absent absent Adhesion Strength, MPa brick surface - 4.7 4.6 4,5 Concrete surface - 3,7 3.6 3,5

Claims (1)

A dry building mixture containing cement, a mineral aggregate comprising sand, characterized in that the mineral aggregate further comprises a zeolite-containing rock at a sand to zeolite-containing rock ratio of 1: 1 with particle sizes of not more than 5 mm in the following ratio, wt.%:
Cement 18.75-25 Sand 37.5-40.625 Zeolite-bearing rock 37.5-40.625