RU2133724C1 - Ornamental concrete mix production method - Google Patents

Abstract

FIELD: construction material industry. SUBSTANCE: method involves mixing white portland cement, filler, plasticizer and whitening addition. White portland cement is preliminarily subject to mechanical activation with plasticizer-superplasticizer, with whitening addition in the form of covered pigment-titanium dioxide based on calcite or microcalcite being introduced 12-15 min before completion of activation process. Mechanically activated cement is mixed with filler upon preparing of cement dough, with water and cement ratio being within the range of 0.3-0.33. Method allows mechanically strong ornamental concrete and products with uniformly colored surface and intensified whiteness to be obtained. EFFECT: increased efficiency and improved quality of concrete and articles produced from such concrete. 1 tbl

Description

 The present invention relates to the construction materials industry, in particular, to methods for manufacturing decorative concrete mixtures.

 A known method of manufacturing a decorative concrete mixture by first preparing the molding material for the decorative layer by sequentially introducing into the water the mixing of superplasticizer, crushed stone, sand and cement; mixing these components to obtain a homogeneous mass and the introduction of coloring additives - pigments. Moreover, to introduce the pigment into the mass, a cement slurry is preliminarily prepared, to which the pigment is added and mixed for 3-20 seconds, after which the cement slurry thus prepared with the pigment is introduced into the molding mass for the decorative layer.

 The prepared mass for the decorative layer is laid on the bottom of the mold and subjected to vibration, then the concrete mixture is laid for the structural layer, vibrocompaction of both layers and their heat treatment, followed by stripping of the finished product / 1 /.

 The significant complexity of the implementation of the method does not make it possible to widely use it in industry.

 The closest to the described by the technical nature and the achieved result is a method of manufacturing a decorative concrete mixture> by mixing white Portland cement, sand aggregate, plasticizer and bleaching additives / 2 /.

 However, the low mechanical strength of concrete, as well as the presence of whitish spots and roughness of the tone of the decorative surface due to migration along the pores of lime used in the composition of the known decorative concrete mix, sharply reduce the effectiveness of the known method.

 The purpose of the invention is to increase the mechanical strength and density of decorative concrete, ensuring a uniformly painted surface of the products, increasing the whiteness of concrete.

 This goal is achieved by the fact that white Portland cement is preliminarily subjected to mechanical activation together with C-3 superplasticizer, moreover, 12-15 minutes before the end of activation, a bleaching additive is introduced into Portland cement in the form of a shell pigment - titanium dioxide on calcite or microcalcite, and the mixing of mechanically activated cement and aggregate produced after the preparation of cement paste with a water-cement ratio of 0.3-0.33.

 The method is as follows. White Portland cement and superplasticizer C-3 are loaded into the vibrating mill and the cement is mechanically activated within 30-40 minutes. 12-15 minutes before the end of mechanical activation, a bleaching additive is introduced into Portland cement.

 To obtain decorative concrete in a gravity-type concrete mixer, water is poured at the calculation W / C = 0.3-0.33; when the motor is on, load activated Portland cement and prepare a cement paste. Then aggregate is loaded into the concrete mixer and all components are mixed for 5-7 minutes until a homogeneous concrete mixture is obtained, from which decorative concrete products are made using traditional technology.

 The essence of the proposed method for the production of decorative concrete mixes is that, thanks to the preliminary mechanical activation of the original white Portland cement together with superplasticizer and the introduction of white pigment into it during activation, it seems possible to obtain high-quality (up to 80 MPa) astringent with a whiteness of more than 80%. The decorative concrete prepared on the basis of such a binder is not only highly durable, but also has a significant density, as a result of which the front surface of concrete has no efflorescences and spots and is characterized by increased whiteness and decorativeness.

 The following are examples of the method.

 Example 1. The source of white Portland cement and superplasticizer C-3 are loaded into a vibrating mill and the cement is mechanically activated for 30 minutes. 12 minutes before the end of activation, a bleaching additive is introduced into Portland cement - shell titanium dioxide (on calcite) in an amount of 15% (by weight of cement). To prepare decorative concrete, water is poured into a gravity-type concrete mixer in the calculation of W / C = 0.3, with the electric motor turned on, mechanically activated white Portland cement is loaded and cement paste is prepared. Then aggregate is loaded into the concrete mixer and all components are mixed for 5 minutes until a homogeneous concrete mixture is obtained, from which concrete products are made using traditional technology.

 Example 2. The manufacturing technology of decorative concrete mixtures - as described in example 1, while the mechanical activation of Portland cement is carried out for 35 minutes, the bleaching additive is titanium dioxide on calcite in an amount of 20% is introduced 15 minutes before the end of cement activation; cement paste from the obtained Portland cement is prepared at B / C -0.32, and mixing of all components of the concrete mixture is carried out for 6 minutes.

 Example 3. The manufacturing technology of decorative concrete mixtures, as described in example 1, while the mechanical activation of Portland cement is carried out for 40 minutes, the bleaching additive - microcalcite - in an amount of 10% (by weight of cement) is introduced 13 minutes before the end of cement activation; cement paste is prepared at W / C = 0.33, and all components of the concrete mixture are mixed for 7 minutes.

 Example 4. The manufacturing technology of decorative concrete mixtures, as described in example 1, while the mechanical activation of Portal cement is carried out for 20 minutes; a bleaching additive - titanium dioxide in the amount of 10% (by weight of cement) is introduced 10 minutes before the end of the cement activation process. Cement dough is prepared at W / C = 0.28, and all components are mixed for 9 minutes.

 Example 5. The manufacturing technology of decorative concrete mixtures, as described in example 1, while the mechanical activation of Portland cement is carried out for 50 minutes; a bleaching additive - titanium dioxide in the amount of 15% by weight of cement is introduced 20 minutes before the end of the cement activation process. Cement dough is prepared at W / C = 0.37, and all components are mixed for 3-4 minutes.

 The test results of samples of decorative concrete made by the proposed method are shown in the table.

 As can be seen from the table, decorative concrete products made by the proposed method are distinguished by increased whiteness, lack of spots, caverns, evenly painted front surface.

Sources of information:
1. USSR author's certificate N 1622163, cl. B 32 B 13/00, 1988.

 2. Application FR N 2520349, cl. C 04 B 15/00, 1982 (prototype).

Claims (1)

 A method of manufacturing a decorative concrete mixture by mixing white Portland cement, aggregate, plasticizer and a bleaching additive, characterized in that the white Portland cement is pre-subjected to mechanical activation together with a plasticizer - superplasticizer C-3, and 12-15 minutes before the end of activation, a bleaching additive is introduced into Portland cement in the form of a shell pigment - titanium dioxide on calcite or microcalcite, and mechanically activated cement and aggregate are mixed after preparation entnogo dough with water to cement ratio of 0.3 - 0.33.

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