RU2750461C1 - Dry mixture for preparing a composition for controlled compensation injection into foundation soil of buildings and structures - Google Patents

Abstract

FIELD: building.

SUBSTANCE: invention relates to the field of reconstruction of building structures, namely to elimination of general deformations thereof. The dry mixture for preparing a bonding composition for controlled compensation injection into foundation soil of buildings and structures comprises, wt.%: cement with low water demand 10 to 50, microcement 15 to 30, organoclay 2 to 7, finely dispersed filler 13 to 73.

EFFECT: high controllable permeability for all types of soils, adjustment of strength gain rate and increased deformative characteristics of the improved soil mass.

1 cl, 2 tbl

Description

FIELD OF TECHNOLOGY

The invention relates to the field of reconstruction of building structures, namely the elimination of their general deformations.

LEVEL OF TECHNOLOGY

Known solution for compensatory injection into the soils of the bases when eliminating deformations of buildings and structures, containing a mixture of water and dry ingredients on a mineral basis. Portland cement in the solution contains 60%, fly ash -38%, plasticizer 2% (Merkin V.E., Makovsky L.V., Pankina S.V. No. 4. - M., 1996. - S. 11-14).

The disadvantage of this solution is the uncontrolled formation of a fortified soil massif, which leads to the appearance of cracks of an indefinite length and opening in it. These cracks require an increased consumption of the solution, they remain partially unfilled with the solution, which can lead to suffosion processes and reverse deformations of the structure.

Closest to the proposed solution is a solution for compensatory injection into the soils of the bases when eliminating deformations of buildings, having the following composition, mass. %:

bentonite 60-80 Portland cement 10-30 hardening accelerator to 10 plasticizer up to 2

(RF patent for invention No. 2622054).

The disadvantage of the composition of this solution is its unstable relative viscosity and low penetrating ability, which requires the use of high pressure when injected into the soil, while the absence of hydraulic fracturing of the soil massif is not guaranteed.

SUMMARY OF THE INVENTION

The objective of the invention is to create a composition for preparing a binder composition for controlled compensatory injection into the soils of the foundations of buildings and structures, which has the following set of properties:

- high controllable penetrating power for all types of soils,

- adjustable rate of strength gain and high deformation characteristics of the fortified soil massif.

The technical result is that the task has been successfully solved, while it was possible to increase the reliability of work to eliminate deformations of buildings and structures by eliminating cracking and hydraulic fracturing in the soil.

The above technical result is achieved due to the fact that the dry mixture for the preparation of a binder composition for controlled compensatory injection into the soils of the bases of buildings and structures contains, masses. %:

low water demand cement 10-50 microcement 15-30 organoclay 2-7 finely dispersed filler from 13-X to 73-X at least one targeted additive X where X up to 5 masses. %

Cement of low water demand (TsNV-100) is a product of joint grinding of Portland cement clinker, calcium sulfate and water-reducing additive (Bikbau M.Ya. Nanotechnology in the production of cement. - M .: JSC "Moscow Institute of Materials Science and Effective Technologies", 2008. - P . 538-607).

The mentioned cement of low water demand, in one of the preferred embodiments, is a cement of low water demand TsNV-100.

Microcement MicroBond MO is a product of air separation of Portland cement with a normalized granulometric composition, the main volume of particles of which has a size of 5 to 15 microns (Panchenko A.I., Kharchenko I.Ya., Alekseev SV. Microcement. M .: Publishing house ASV, 2014 . - P. 4).

Said microcement, in one preferred embodiment, is a MicroBond MC brand microcement.

Microcement, in one of the preferred embodiments, has a normalized particle size distribution with a particle size of more than 75% of particles less than 10 microns.

Cement of low water demand and microcement, in combination, form a binder base that provides uniform injection of the binder composition and a controlled increase in strength for three or more hours of hardening of the soil mass.

Organoclay is a modified montmorillonite clay, a nanosized layered silicate filler obtained as a result of mechanochemical treatment of natural montmorillonite clay with a solution of a cationic surfactant (Golubeva O.Yu., Gusarov V.V. // Physics and chemistry of glass. - 2007. V. 33. No. 3. P. 334-340).

Organoclay regulates the viscosity and penetrating ability of the composition obtained from the mixture by changing the pseudoplasticity, the ratio to the ionic composition and pH of the soil due to changes in the surface and adsorption properties of montmorillonite clay when it is modified with cationic surfactants.

Organoglana regulates the kinetics of the strength gain of the soil massif and increases the strength by reducing the water separation of the composition into the soils of the foundations of buildings and structures due to its high water-holding capacity and the presence of surfactants in its structure.

Microcement in combination with organoclay provides an increase in the adhesion of the composition to soil particles.

As a finely dispersed filler, finely dispersed mineral fillers are suitable, which do not adversely affect the remaining components of the mixture. The preferred fine filler is chalk or microcalcite, i. E. finely ground natural calcium carbonate (Korneev V.I., Zozulya P.V. Dictionary "What is what" in dry building mixtures. - SPb .: NP "Union of dry building mixture producers". 2005. - pp. 110, 148-149 ). The particle size of the finely dispersed filler should correspond to the size of the particles of the remaining components of the mixture and allow the composition prepared from the mixture to penetrate relatively freely into the pores of the soil under pressure. It is preferable when the particle size distribution of the filler is normalized and particles with a size of less than 5 microns prevail (more than 75% of particles).

CARRYING OUT THE INVENTION

6 compositions of the composition for controlled compensatory injection into the soils of the foundations of buildings and structures have been tested:

compositions No. 1-3 with the claimed content of components;

composition No. 4 with a content of components outside the minimum declared limits;

composition No. 5 with a content of components outside the maximum declared limits;

composition No. 6 was prepared according to the prototype.

For the manufacture of the claimed composition (compositions 1-6), the following raw materials were used:

- cement of low water demand, made by joint grinding of Portland cement clinker, natural gypsum stone and polycarboxylate ether solution as a water-reducing additive;

- modified by treatment with a solution of a cationic surfactant montmorillonite clay with a predominant particle size of less than 5 microns;

- finely dispersed mineral filler;

- bentonite;

- Portland cement;

- plasticizer Synergy PM-1000;

- hardening accelerator Synergy PM - 1200 R.

The compositions of the compositions tested are shown in Table 1.

Binder compositions for controlled compensatory injection into the soils of the foundations of buildings and structures were prepared as follows:

The test dry mixtures are introduced into the volume of water required for the preparation of the binder composition for controlled compensatory injection into the soils of the bases of buildings and structures and mixed for 5-10 minutes at a stirrer speed of 2500-3000 rpm. In this case, the water-solid ratio is taken equal to 1.

To determine the strength of the soil mass, samples were taken from a volumetric model manufactured in accordance with GOST 12248-2010 “Soils. Methods for determining the characteristics of strength and deformability ", which were tested at the age of 7 and 28 days.

The test results of cementitious compositions for controlled compensatory injection into the soils of the foundations of buildings and structures are shown in Table 2.

As can be seen from the data given in the tables, the use of binder compositions for controlled compensatory injection into the soils of the foundations of buildings and structures of compositions No. 4 and No. 5 is impractical. The composition for controlled compensatory injection into the soils of the foundations of buildings and structures of composition No. 4 has low deformability indicators of the soil massif, and the composition of composition No. 5 has a low conditional viscosity.

When outside the claimed range of the content of cement with low water demand (TsNV-100) and MicroBond MC microcement of a normalized particle size distribution with a predominant particle size of less than 10 microns (more than 75%), delamination and water separation of the binder composition occurs for controlled compensation injection into the soils of the foundations of buildings and structures , which leads to a decrease in the deformative characteristics of the soil mass.

Analysis of the test results of the compositions according to the invention showed that, in comparison with the composition taken as a prototype, they have the following properties:

- increase the strength of the soil mass by 1.6 times;

- have close to zero sedimentation within 90 minutes;

- have a conditional viscosity of 84%;

- provide an adjustable set of strength within the standard hardening time.

All this makes it possible to achieve a reduction in labor and material costs, to increase the reliability of the pre-strengthened soil massif by increasing its homogeneity, strength and elimination of hydraulic fracturing.

Claims (7)

1. A dry mixture for preparing a binder composition for controlled compensatory injection into the soils of the foundations of buildings and structures, containing, wt%: low water demand cement 10-50 microcement 15-30 organoclay 2-7 finely dispersed filler 13-73 2. A mixture according to claim 1, wherein said low water demand cement is a low water demand cement TsNV-100. 3. A mixture according to claim 1, wherein said microcement is MicroBond MC grade. 4. A mixture according to claim 1, in which the microcement has a normalized particle size distribution with a particle size of more than 75% of particles less than 10 microns. 5. A mixture according to claim 1, wherein said filler is chalk or microcalcite. 6. A mixture according to claim 1, wherein more than 75% of the filler particles are less than 5 microns in size.