RU2764758C1 - Composite raw mix for manufacture of hydraulic piles - Google Patents

Abstract

FIELD: building materials.

SUBSTANCE: solution relates to building materials and can be used for the manufacture of hydraulic piles. The composite raw mixture for the manufacture of hydraulic piles contains Portland cement, crushed stone, sand, fly ash, superplasticizer, water, and MasterGlenium ACE 430 was taken as a superplasticizer on a polycarboxylate ether base and additionally a viscosity modifier MasterMatrix 100 was introduced at the following ratio of components, wt.%: Portland cement 15.86-17.84; fly ash 1.984-3.96; sand 37.4-37.82; crushed stone 33.28-33.7; superplasticizer 0.14-0.16; a viscosity modifier 0.016-0.020; water 8.5-9.32.

EFFECT: increase in strength, water resistance, coefficient of expansion of coarse aggregate grains and coefficient of hydraulicity.

1 cl, 4 tbl

Description

The invention relates to building materials and can be used for the manufacture of hydraulic piles.

Known composition of the concrete mixture is given in the patent of the Russian Federation No. 2435746, IPC ⁸ SW 28/04, SW 111/20. It includes components: Portland cement grade not lower than M500 150-300; superplasticizer based on polycarboxylate ether 10-15% by weight of cement in terms of dry matter; microsilica 10-15% by weight of cement; quartz or feldspar sand 400-550; crushed stone from dense rocks 800-850; ground quartz sand or stone flour 150-250; very fine quartz sand 400-500, water 140-170.

Along with the advantages (low consumption of cement per unit strength, no more than 4.5 kg / MPa), there are also disadvantages: crushed stone is used from dense rocks, crushability grade 800-1400, which is scarce and expensive; insufficient rheological properties.

The composition of the concrete mixture is known (RF patent No. 2616964, IPC S04V 28/04, S04V 24/26, S04V 18/24, 2017) including Portland cement, quartz sand, granite crushed stone, finely ground filler, additive and water containing as sand - quartz sand with a fineness modulus of 2.2, as a finely ground filler - finely ground limestone with a specific surface area of 260 m ² /kg, and as an additive - various chemical modifiers.

The disadvantage of this concrete is the need for significant compaction in the formwork.

Self-compacting concrete is known (RF patent No. 2679322, IPC ⁸ С04В 28/04, С04В 24/26, С04В18/24, 2019) containing: Portland cement CEM I 42.5N; rice husk ash; fine aggregate - sand 40%; crushed stone 31-32%, superplasticizer based on polycarboxylate ether 0.7-1%; water 7-9%.

The disadvantage of this concrete is a low coefficient of grain expansion, significant water permeability.

The composition of the composite raw mix is given in the patent RU 2569947 MPK S04V 28/04 dated 12/10/2015. "Sandy concrete" has the following composition, wt %: Portland cement 16.7-18.4; quartz sand 68.4-70.0; WHVO 1.2-2.5; microsilica 0.8-2.8; hyperplasticizer Melflux 2651 F 0.08-0.09; water 8.91-10.11, while the specific surface of the WHVO is from 1200 to 1300 m ² /kg.

The disadvantage of this technical solution is the low coefficient of hydraulicity, increased water permeability.

The closest composition of the composite raw mix is given in the patent RU 2307810C, IPC ⁸ С04В 28/04, В28С 5/00, С04В 24/24, С04В 103/32, С04В 111/22 dated 10.10.2007 “Concrete mixture and its method cooking" contains: Portland cement 12.5-16.5%; crushed stone 39-40%; sand 27-29.3%; bentonite 0.15-0.25%; fly ash 7.5-8.5%; superplasticizer based on polycarboxylate ester (Addiment FM 40) 0.3-0.35%; water 9.5-10%.

The disadvantage of this technical solution is the lack of strength due to the low coefficient of expansion of grains of coarse aggregate, a low coefficient of hydraulicity and increased water permeability.

The objective of the technical solution is to increase the strength and water tightness by increasing the coefficient of expansion of coarse aggregate grains and the coefficient of hydraulicity.

To solve this problem, a composite raw mix for the manufacture of hydraulic piles is proposed, containing Portland cement, crushed stone, sand, fly ash, superplasticizer, water, and MasterGlenium ACE 430 is taken as a superplasticizer on a polycarboxylate ester base and the viscosity modifier MasterMatrix 100 is additionally introduced in the following ratio of components , mass %:

Portland cement 15.86-17.84; fly ash 1.984-3.96; Sand 37.4-37.82; rubble 33.28-33.7; Superplasticizer 0.14-0.16; Viscosity modifier 0.016-0.020; Water 8.5-9.32.

The composition of the proposed composite raw mix for the manufacture of hydraulic piles and the prototype is shown in table 1.

The following ratios were adopted as a criterion for evaluating the coefficient of hydraulicity and the coefficient of expansion of grains of coarse aggregate:

Characteristics of materials

1. Cement (Branch of HeidelbergCement Rus LLC in Novogurovsky village - Aleksinsky district, Tula region). Portland cement type TsVM I strength class 42.5, normally hardening according to GOST 31108-2016:

- strength class (MPa): not less than 42.5;

- average activity of cement at the age of 2 days (MPa): 28.4;

- auxiliary components (%): 4.5;

- special additives (%): no;

- technological additives (grinding intensifier) (%): 0.02;

- normal density of cement paste (%): 28.60;

- false grasp: no;

- uniformity of volume change (expansion) mm, at a rate of not more than 10 mm: 1.0;

- specific effective activity of natural radionuclides (Bq/kg), at a rate of not more than 370 Bq/kg: 134.

2. Fly ash brand KUK-4 in accordance with GOST 25818-2017 (branch "Cherepetskaya GRES named after D.G. Zhimerin" JSC "Inter RAO - Electric Power Generation" - Tula region, Suvorov.):

- residue on sieve No. 008, %: 5.5;

- specific surface, cm ² /g: 3000;

- humidity, %: 0.10;

- bulk density: 1.40;

- specific activity of natural radionuclides, Bq/kg: 221.

3. Sand (TorgService 71 LLC, Vorovaevskoye deposit - Kaluga region). Sand (river) according to GOST 8736-2014:

- class, group: 2 class; gr. "Small";

- fineness modulus: 1.71;

- total residue on sieve No. 063, %: 10.28;

- content of clay and dust-like particles, %: 1.12;

- specific effective activity of radionuclides (Aeff), Bq/kg: 23.88 (±20.20);

- filtration coefficient, m/day: 6.

4. Crushed stone from dense rocks (LLC "Obukhov shchebzavod", Obukhovskoye deposit - Rostov region, Krasnosulinsky district).

Crushed stone of a mixture of fractions from 5 to 20 mm according to GOST 8267-93:

Grade of crushed stone according to crushability: 1200;

Brand of crushed stone on abrasion: I1;

Frost resistance grade: F200;

Bulk density for converting the amount of material from units of mass to volume: 1.42 t/m ³ ;

The content of grains of weak rocks is 0.3% by weight;

Specific effective activity of radionuclides (A eff.): 247±17 Bq/kg, first class of use;

The stability of the structure of crushed stone against decay is 1.6%;

The content of lamellar (flaky) and needle-like grains is 13.24%, 2 gr.;

The content of dust and clay particles 0.46% by weight;

Clay content in lumps 0.00% by weight;

The content of harmful components and impurities:

- hard coal up to 0%,

- pyrite up to 0.01%,

- sulfates up to 0.02%.

5. Superplasticizer - MasterGlenium ACE 430 (LLC "New construction technologies" - Tula, the official dealer of BASF). Highly water reducing/superplasticizing additive based on polycarboxylate ester for the production of precast concrete products and structures. (Solution based on polycarboxylate and water):

- manufacturer: BASF ("Badische Anilin- & Soda-Fabrik" / "Badische Anilin-und Soda-Fabrik" - Germany);

- appearance: homogeneous liquid of orange or light brown color;

- density at 20°C, g/cm: 1.06±0.02;

- pH value, pH: 5.5;

- content of Cl-ion, in mass. %, no more: 0.1.

6. Viscosity modifier MasterMatrix 100 (LLC "New construction technologies" - Tula, the official dealer of BASF). Highly effective additive based on an aqueous solution of a high molecular weight synthetic polymer - viscosity modifier for flowable and self-compacting concrete:

- manufacturer: BASF ("Badische Anilin- & Soda-Fabrik" / "Badische Anilin-und Soda-Fabrik" - Germany);

- appearance: homogeneous liquid of light brown color;

- density, kg/m: 1010;

- pH value, pH: 8;

- content of Cl-ion, in mass. %, no more: 0.1.

7. Water for concrete and mortar according to GOST 23732-2011.

Implementation example

The preparation of the developed composite raw material mixture for the manufacture of hydraulic piles was carried out as follows. First, Portland cement, crushed stone, sand, fly ash are mixed in dry form for 15-25 seconds until a homogeneous mixture is obtained, the superplasticizer and viscosity modifier are dissolved in the entire amount of mixing water, after which 2/3 of the resulting aqueous solution is introduced into the dry mixture and mixed for 25-35 seconds, then the remaining 1/3 of an aqueous solution of superplasticizer and viscosity modifier is introduced into the resulting mixture and mixed again for 35-55 seconds.

Dividing the superplasticizer aqueous solution into two parts and alternately introducing into the dry mixture first 2/3 of the superplasticizer aqueous solution, stirring, and then introducing the remaining 1/3 of the superplasticizer aqueous solution and re-mixing allows the dry mixture to adsorb all the water, which is impossible with the simultaneous introduction of the entire amount aqueous solution, since with the simultaneous introduction of all water, it is completely adsorbed on the surface of aggregates and binder.

From each developed composition of the composite raw mix for the manufacture of hydraulic piles and a prototype, twelve samples-cubes 100 × 100 × 100 mm were manufactured (molded without compaction and vibration) in accordance with the requirements of GOST 10181-2014, GOST 18105-2018 and GOST 7473-2010 in pre-cleaned and lubricated forms that meet GOST 22685-89. The laying of the mixture was carried out immediately after its preparation.

The cubes were subjected to heat treatment, on the stand, at a temperature of t=45±5°C. Maintenance time - 20 hours. Demoulding of the samples was carried out after heat treatment. After stripping, the samples were stored at t=20±5°C at a humidity of 90-95%. The test results are shown in table 4.

Analysis of test results

The proposed technical solution made it possible to obtain a composite raw material mixture for the manufacture of hydraulic piles with improved physical and mechanical characteristics in relation to the prototype.

From the analysis of the test results, it can be seen that the optimal composition is No. 2, since it ensures the fulfillment of the task of the technical solution.

According to the results of comparing the indicators of the developed composite raw mix for the manufacture of hydraulic piles with the indicators of the prototype, it was established:

- compressive strength of samples increased by 20%;

- hydraulic coefficient increased by 15%;

- the coefficient of separation of the grains increased by 12%.

The hardening mechanism is characterized by the ability of such composite concrete mixtures to spread and compact under the action of their own weight. High-quality formwork filling occurs without the use of external and internal vibration. The concrete mixture can be fed to the place of laying through the pipeline, while maintaining its uniformity.

The rheological properties of such mixtures are evaluated not only traditionally, according to the standard cone slump, but also according to the flow, capable of self-leveling concrete mixture.

Claims (2)

Composite raw mix for the manufacture of hydraulic piles contains Portland cement, crushed stone, sand, fly ash, superplasticizer, water, characterized in that MasterGlenium ACE 430 is taken as a superplasticizer on a polycarboxylate ester base and the viscosity modifier MasterMatrix 100 is additionally introduced in the following ratio of components, wt. %: Portland cement 15.86-17.84 fly ash 1.984-3.96 Sand 37.4-37.82 rubble 33.28-33.7 Superplasticizer 0.14-0.16 Viscosity modifier 0.016-0.020 Water 8.5-9.32