RU2553667C1 - Preparation method of portland cement binding agent with addition of high-lime ash of thermal power plants - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: in preparation method of Portland cement binding agent with addition of high-lime ash of thermal power plants, including the combined melting of active mineral additive, Portland cement clinker, gypsum stone, domain granulated slag, their mixing, addition of high-lime ash into the binding agent are carried out at the moment of preparation of concrete or solution mixture within the ratio of 10:90 - 50:50. Invention is developed in the dependent claims of definition of the invention.

EFFECT: reduction of energy consumption without reduction of strength and without increase of deformation of expansion.

3 cl, 2 tbl

Description

The invention relates to the field of building materials and can be used in the production of various concrete and mortar mixtures.

A known method of preparation of a Portland cement binder with the addition of high-calcium ash (VKZ) of thermal power plants (CHP), including the preliminary activation of the ash of hydraulic removal of thermal power plants, followed by mixing with cement (RU 2351563, 04/10/2009). The disadvantage of this method is that it requires additional costs for pre-activation, in addition, in this method, the ash of thermal power plants with a low amount of calcium is used, which greatly simplifies the monitoring of the strength of the concrete obtained.

Closest to the claimed invention (prototype) is a method of preparing a Portland cement binder with the addition of high-calcium ash from thermal power plants, including mixing and grinding Portland cement clinker, gypsum stone, blast furnace slag, active mineral additives, high-calcium ash from thermal power plants (RU 2376253, 12.20.2009).

The disadvantage of the prototype is that it is technologically impossible to produce a binder with a wide range of ratios at a cement plant or at a grinding plant for a binder consumer: Portland cement: high-calcium ash from a thermal power plant. At the same time, different concrete and mortar mixes often require rapid changes in this ratio over a wide range, which will save more Portland cement and improve the technological properties of concrete and mortar mixes. When VKZ is introduced as an independent component directly into water (a component of a concrete mix), because of the very short setting time of VKZ, a rapid increase in the viscosity of the composition can occur, which will make it impossible to use it in concrete or mortars.

The present invention solves the problem of reducing energy consumption for the production of Portland cement and increasing the saving of cement in concrete and mortar mixtures containing high calcium ash, without reducing strength and increasing expansion deformations.

To achieve the named technical result in a method for preparing a Portland cement binder with the addition of high-calcium ash of thermal power plants, including joint grinding of the active mineral additive, Portland cement clinker, gypsum stone, blast furnace slag, mixing them, adding high-calcium ash to the binder is carried out at the time of preparation of the concrete or mortar mixture ratio 10: 90-50: 50. Natural or artificial pozzolans are used as an active mineral supplement. The active mineral additive in the mixture subjected to grinding is 3-10%.

An example of a specific embodiment of the invention

At thermal power plants, 2 samples of high-calcium ash are taken twice a week. In ash, among other indicators, the temperature effect of hydration Δt and the content of total free lime CaO sv. ^sums . These indicators are indirect characteristics of the basicity and activity of ash. The indicators are listed in table 1.

A cement plant produces Portland cement (PC) grade M400 according to GOST 10178-85 “Portland cement and slag Portland cement. Specifications ”, which includes 77% of Portland cement clinker, 5% of gypsum stone, 8-15% of blast furnace slag and from 3 to 10% of an active mineral additive of sedimentary origin in the form of a flask. The mixture (Portland cement clinker, gypsum stone, blast furnace slag and an active mineral additive) was subjected to joint grinding.

Two samples of high-calcium ash from Barnaul TPP-3, taken after electrostatic precipitators, were used to produce heavy M200 concrete from concrete mix with mobility P4 according to GOST 7473-94 “Concrete mixtures. Specifications "for cassette forming of panels for large-panel residential buildings.

On the basis of the obtained Portland cement and samples of high-calcium ash, heavy concrete is made. An example of a specific embodiment of the invention.

The composition of the winter concrete mixture included (kg / m ³ ):

Portland cement - 400

Ob sand with particle size modulus MK = 1.2-660

Crushed stone from gravel of the Verkh-Katunsky crushing and screening plant (DSF) of a fraction of 5-15 mm - 970

Water - 210-230

Plasticizer Additive - 16

The properties of the samples used by VKZ are shown in table 1. Portland cement with active mineral additives (AMD) was obtained by grinding clinker of the Golukhinsky cement plant OJSC Cement, Altai Territory, gypsum stone, blast furnace slag (DGSh) of the West Siberian Metallurgical Plant and AMD in the form of silica fume ( MK) of the plant Kuznetsk ferroalloys (artificial pozzolana) and Inza flask (Ulyanovsk region) - natural pozzolana. In accordance with GOST 10178-85 "Portland cement and slag Portland cement" the content of MK and flask should not exceed 10% in the composition of Portland cement. Therefore, the PC 400 D20 contained, in addition to clinker, 5% gypsum stone, 3-10% AMD and 8-15% DHS.

The test results of concrete mixtures and solutions obtained from components containing Portland cement and high-calcium ash prepared by the proposed method are shown in table 2.

Note: the amount of binder in concrete mixtures increased in proportion to the ratio VKZ: PC. The excess binder was compensated by a decrease in either sand or gravel, or sand and gravel together.

As can be seen from table 2, for all ratios VKZ: PC from 10:90 to 50:50 and in the presence of at least 3% AMD in Portland cement, it is possible to choose such a quantity of binder that will provide the required concrete strength. The ratio VKZ: PC above 50% leads to a sharp loss of mobility of concrete and mortar mixtures within 20-30 minutes, i.e. they do not have the required persistence of workability over time. In accordance with GOST 7473-2010 “Concrete mixtures. Technical conditions ”minimum mobility retention time must be at least 1 hour 30 minutes (-10 minutes).

The decrease in the strength of concrete with VKZ additive on cement with a content of less than 3% AMD is explained by an increase in concrete destruction due to the quenching of free ash lime, which did not bind to AMD, because AMD was not enough. This can be traced by the elongation strains of the samples in table. 2.

The application of the proposed method for the preparation of a Portland cement binder with the addition of high-calcium ash from thermal power plants made it possible to simplify the technology, reduce energy consumption and more efficiently use high-calcium ash in a higher percentage ratio to Portland cement, without loss of quality of concrete and mortars.

Claims (3)

1. A method of preparing a Portland cement binder with the addition of high calcium ash from thermal power plants, including co-grinding an active mineral additive, Portland cement clinker, gypsum stone, blast furnace slag, mixing them, characterized in that the addition of high calcium ash to the binder is carried out at the time of preparation of the concrete or mortar mixture within ratios 10:90 - 50:50. 2. The method according to p. 1, characterized in that as the active mineral additives use natural or artificial pozzolans. 3. The method according to p. 1, characterized in that the active mineral additive in the mixture subjected to grinding is 3-10%.