RU2473493C1 - Fine-grain cement - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to construction materials and can be used for manufacturing products from fine-grain cement, both in civil and in industrial construction. Fine-grain cement is obtained from mixture, which contains Portland cement, fractioned quartz sand with coarseness module 2.7-3.2, ground quartz sand with specific surface S_sp=500-700 m/kg, hyperplasticiser "Melflux 265IF" and defoaming agent TSOP, with the following component ratio, wt %: Portland cement 16.0-22.0, quartz sand 69.4-75.9, ground quartz sand 1.6-2.2, hyperplasticiser "Melflux 265IF" 0.08-0.12, defoaming agent TSOP - 0.016-0.022, water the remaining part.

EFFECT: increase of mobility and reduction of air involvement of cement mixture, increase of cement compression resistance at design age.

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Description

The invention relates to building materials and can be used for the manufacture of concrete products in civil and industrial construction.

Known raw mix for the preparation of concrete, including Portland cement, screening crushing quartzite sandstone, mechanically activated screening quartzite sandstone and water with the following ratios of components, kg / m ³ :

Portland cement 300-350 Quartzite sandstone crushing screening 1100-1300 The specified screening quartzite sandstone mechanically activated 90-140 Water Rest

(patent RU 2389703, IPC С04В 28/04, С04В 111/20, 2010).

The disadvantage of this mixture is its low compressive strength, low mobility and high air entrainment.

The closest in technical essence to the claimed invention is fine-grained concrete containing Portland cement, aggregate - glauconite sand, filler - ground glauconite sand with a specific surface S _beats = 350 m ² / kg, superplasticizer C-3 and water in the following ratio of components, wt. %:

Portland cement 18.0-19.0 Aggregate - glauconite sand 68.1-68.9 Filler - ground green earth sand 1.0-2.0 Superplasticizer S-3 0.1-0.2 Water 11.0-11.7

(patent RU 2358938, IPC С04В 28/04, 2010).

The disadvantage of this technical solution is the low mobility and high air entrainment of the concrete mixture, the low compressive strength of concrete at the design age.

The problem to which the invention is directed, is the creation of fine-grained concrete from a mixture of high mobility, with low air entrainment and increased compressive strength at design age.

The solution to the problem is achieved by the fact that the fine-grained concrete obtained from a mixture containing Portland cement, aggregate, silica-containing component, additives and water, according to the invention contains quartz sand with a particle size of 2.7-3.2 as a filler, as a silica-containing component - ground quartz sand with a specific surface area S _ud = 500-700 m ² / kg, and as additives - the product based on modified polycarboxylate - giperplastifikator «Melflux 2651 F» and CSC antifoam based on an aqueous emulsion hydroxypropyl th polymer with an emulsifier - a mixture of polyoxyethylene esters of oleic acid, with the following component ratio, wt.%:

Portland cement 16.0-22.0 Quartz sand 69.4-75.9 The specified silica-containing component 1.6-2.2 Hyperplasticizer "Melflux 2651 F" 0.08-0.12 Specified CPO Defoamer 0.016-0.022, Water Rest

Characterization of substances used to obtain fine-grained concrete.

Portland cement - in accordance with GOST 31108-2003 “Cement for general construction. Technical conditions. "

Quartz sand - in accordance with GOST 8736-93 "Sand for construction work. Technical conditions. "

Antioxidant CPO based on an aqueous emulsion of an oxypropylated polymer with an emulsifier - a mixture of polyoxyethylene glycol esters of oleic acid according to TU 2229-136-00203335-2001.

Melflux 2651 F hyperplasticizer is a product obtained by spray drying based on a modified polyester carboxylate manufactured by Degussa Constraction Polymers (SKW Trostberg, Germany).

Aggregate - quartz sand with a particle size modulus of 2.7-3.2. With a smaller modulus of fineness of quartz sand, the air entrainment of the mixture increases during the preparation of fine-grained concrete, and with a larger modulus of fineness of quartz sand, stratification of the mixture is observed. The use of quartz sand of this size can reduce the water-cement ratio, which leads to hardening of concrete.

Silica-containing component in the form of ground quartz sand with a specific surface S _beats = 500-700 m ² / kg allows to reduce the air entrainment of the concrete mixture. In addition, it binds portlandite to low-basic calcium hydrosilicates, which strengthens the cement stone.

The use of Melflux 2651 F hyperplasticizer can significantly reduce the amount of mixing water in fine-grained concrete and increase the mobility of the concrete mixture.

CPA antifoam reduces air entrainment in the concrete mix.

Thus, the concrete mix, consisting of Portland cement, aggregate, silica-containing component, Melflux 2651 F hyperplasticizer and CPA antifoam, has low water demand, high mobility, low air entrainment, which ultimately leads to increased concrete strength. The claimed invention is applicable and can be used in industrial and civil engineering.

The order of preparation of the concrete mixture is as follows:

1. Dose Portland cement, quartz sand with a particle size modulus of 2.7-3.2, ground quartz sand with a specific surface area S _beats = 500-700 m ² / kg.

2. Dose water.

3. The Melflux 2651 F hyperplasticizer and the CPA antifoam are dosed, they are added to the prepared water together.

4. Dosage components: Portland cement, silica sand, silica-containing component and water with a Melflux 2651 F hyperplasticizer and a DSP antifoam are loaded into a concrete mixer, where they are mixed until a homogeneous mass is obtained. Next, concrete products and control samples are made in accordance with GOST 10180. The samples are divided into two series. One series of samples is stored under normal conditions, the other is subjected to heat-moisture treatment (TVO) in a steaming chamber according to the 2 + 3 + 5 + 4 hours regime. The compositions of the concrete mix of fine-grained concrete are presented in table 1. The test results are presented in table 2.

table 2 Indicator Structure prototype one 2 3 four 5 The mobility of the mixture (sediment cone, cm) P1 P4 P4 P4 P4 (3) (17) (16) (16) (17) The air involvement of the mixture,% - 9.1 5.2 4.9 4.7 4.6 The limit of compressive strength, MPa - after TVO 18.9 17.1 30.3 42.0 53.7 62.6 - at the age of 28 days - 22.8 40,4 56.0 71.6 83.5

Analysis of the data presented in tables 1, 2, shows that the proposed composition of fine-grained concrete according to this invention, in comparison with the prototype, is characterized by increased compressive strength. At the same time, the concrete mixture has high mobility and low air entrainment.

The combined introduction of the Melflux 2651 F hyperplasticizer and the CPA antifoam allows halving the air entrainment of the concrete mixture, while their separate administration reduces this indicator only by 35-40%. Due to this, an increase in the strength of fine-grained concrete by more than 3.5 times is achieved.

Claims (1)

Fine-grained concrete obtained from a mixture containing Portland cement, aggregate, silica-containing component, additives and water, characterized in that it contains silica sand with a fineness modulus of 2.7-3.2 as a filler, and ground silica sand with silica-containing component specific surface area S _beats = 500-700 m ² / kg, and as additives - a product based on modified polycarboxylate - Melflux 2651 F hyperplasticizer and CPA antifoam in the following ratio of components, wt.%:
Portland cement 16.0-22.0 quartz sand 69.4-75.9 specified silica-containing component 1.6-2.2 Melflux 2651 F hyperplasticizer 0.08-0.12 antioxidant 0.016-0.022 water rest