Low shrinkage finish decorative white ultra high performance concrete spray material and preparation method

Abstract

The application provides a low-shrinkage surface-decorating white ultra-high performance concrete spraying material, which comprises the following components in parts by weight: 700-800 parts of white cement, 130-160 parts of white silica ash, 120-150 parts of quartz powder, 15-25 parts of titanium white powder, 650-750 parts of shrinkage-reducing components, 600 parts of white quartz sand, 1-1.5 parts of defoaming agent, 8-12 parts of polycarboxylic acid water reducing agent, 200-220 parts of water, wherein the shrinkage-reducing components are obtained by ultrasonic mixing and drying of high bauxite aggregate and white sulphoaluminate cement in a silane coupling agent at a mass ratio of 1:(0.1-0.15). The spraying material has low shrinkage, a 180d drying shrinkage of less than -90με, excellent volume stability, can effectively avoid cracks on the surface of the surface-decorating white ultra-high performance concrete, and has excellent durability and construction performance.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a low-shrinkage surface decorative white ultra-high performance concrete spraying material and its preparation method. Background Technology

[0002] In recent years, with the continuous and in-depth research and industrial application of ultra-high performance concrete (UHPC) materials at home and abroad, its construction technology and application scenarios have become more diversified. Among them, white ultra-high performance concrete is favored by the public because of its integrated decoration and structure characteristics.

[0003] Due to the individualization of different types of buildings and the demand for aesthetic quality, conventional pouring construction methods can no longer meet the requirements, thus giving rise to spraying technology. For example, Chinese invention patent with publication number CN201910627894.X discloses a sprayable ultra-high performance decorative concrete material and its preparation method. It uses white silicate cement, slag powder, and white silica fume as cementing materials, white quartz sand as aggregate, and adds polymer emulsion, bentonite, hydroxyethyl cellulose, starch ether, and chemical admixtures such as defoamers, early strength agents, expanding agents, and water-reducing agents. It also incorporates alkali-resistant glass fiber to prepare the sprayable ultra-high performance decorative concrete material. Chinese invention patent with publication number CN202310643320.8 discloses a high-performance decorative concrete spray material and its processing equipment. It increases the solidification temperature of the spray material by adding quicklime to the concrete spray material, adds talc powder to improve the whiteness and uniformity of the spray material surface, and uses self-designed processing equipment to prepare the high-performance decorative concrete spray material, so that the spray material can be quickly solidified after spraying and the strength during the solidification process can be improved.

[0004] While the above methods can produce spray-applied decorative ultra-high performance concrete (UHPC), the high amount of cementitious materials in UHPC makes the surface of the prepared decorative components highly susceptible to microcracks or even full cracking due to shrinkage. Furthermore, due to differences in the water requirement, reaction characteristics, and expansion amount of expansive agents, adding expansive agents to reduce UHPC shrinkage leads to poorer volume stability and reduced mechanical properties, ultimately resulting in decreased long-term durability and a shorter service life. Summary of the Invention

[0005] To address the problems existing in the background technology, the present invention provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material and preparation method, which can effectively balance excellent mechanical properties, workability, volume stability and durability, and can effectively solve the problem of cracking on the surface of decorative white ultra-high performance concrete, thereby improving the appearance quality.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] In a first aspect, the present invention provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material, comprising the following components in parts by weight: 700-800 parts white cement, 130-160 parts white silica fume, 120-150 parts quartz powder, 15-25 parts titanium dioxide, 650-750 parts shrinkage reducing component, 600 parts white quartz sand, 1-1.5 parts defoamer, 8-12 parts polycarboxylate superplasticizer, and 200-220 parts water; wherein the shrinkage reducing component is obtained by ultrasonic mixing and drying of high-alumina bauxite aggregate and finely ground white sulfoaluminate cement in a mass ratio of 1:(0.1-0.15) in a silane coupling agent.

[0008] According to the above scheme, the shrinkage-reducing component is prepared by the following method: high-alumina bauxite aggregate and finely ground white sulfoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15), and a silane coupling agent with a mass concentration of 5% to 8% is added and ultrasonically mixed for 10 to 15 minutes, and then dried to obtain the shrinkage-reducing component.

[0009] According to the above scheme, the alumina content of the high-alumina bauxite aggregate is not less than 80wt%, the particle size is 0-1mm, and the white sulfoaluminate cement is grade 62.5 with a whiteness ≥85% and a fineness not greater than 600 mesh.

[0010] According to the above scheme, the white cement is PW.52.5 white silicate cement with a whiteness ≥87%.

[0011] According to the above scheme, the specific surface area of ​​the white silica fume is ≥15000 m². 2 / kg, 28d activity index ≥100%, whiteness ≥85%, SiO2 mass content ≥95%.

[0012] According to the above scheme, the fineness of the quartz powder is no greater than 300 mesh, and the whiteness is ≥90%.

[0013] According to the above scheme, the titanium dioxide is of the rutile type with a whiteness ≥95%, and the white quartz sand is 40-80 mesh with a fineness modulus of 1.4 to 1.8.

[0014] According to the above scheme, the defoamer is an organosilicon defoamer or a polyether defoamer, and the water reduction rate of the polycarboxylate superplasticizer is ≥25%.

[0015] Secondly, the present invention provides a method for preparing the above-mentioned low-shrinkage surface decorative white ultra-high performance concrete spraying material. High-alumina bauxite aggregate and finely ground white sulfoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15), and a silane coupling agent with a mass concentration of 5%-8% is added. The mixture is ultrasonically mixed for 10-15 minutes, dried to obtain a shrinkage-reducing component. Then, the formulated amounts of white cement, white silica fume, quartz powder, titanium dioxide, shrinkage-reducing component, white quartz sand, and defoamer are placed in a mixer and stirred uniformly for 4-6 minutes. While stirring, the formulated amounts of polycarboxylate superplasticizer and water are added, and the mixture is stirred for 6-10 minutes until uniformly mixed to obtain the low-shrinkage surface decorative white ultra-high performance concrete spraying material.

[0016] The beneficial effects of this invention are:

[0017] 1. This invention uses a composite of quartz powder, high-alumina bauxite aggregate and white quartz sand. By utilizing the difference in particle size, a dense skeleton packing principle is adopted to form a tight packing between different particle gradations, providing a skeleton structure and ensuring the strength of the matrix.

[0018] 2. This invention involves ultrasonically mixing high-alumina bauxite aggregate with white sulfoaluminate cement in a silane coupling agent, followed by drying to obtain a shrinkage-reducing component. This allows the white sulfoaluminate cement particles to be stably adsorbed within the pore structure of the high-alumina bauxite aggregate particles. As the hydration of the cementitious material continues and water molecules penetrate, the pore structure equilibrium is disrupted. The white sulfoaluminate cement particles are gradually released and detached from the pores, participating in the hydration reaction and continuously and slowly generating hydration products with expansive properties, such as CSH gel, calcium aluminate gel, monosulfide hydrated calcium sulfoaluminate (AFm), and trisulfide hydrated calcium sulfoaluminate (AFt). The generation of these hydration products not only improves the strength of ultra-high performance concrete but also reduces its shrinkage. Simultaneously, the white sulfoaluminate... The high-alumina bauxite aggregate particles formed by the separation of cement particles absorb moisture through their pores. This absorbed moisture is slowly released during the continuous hydration process of the cementitious material, achieving both moisture retention and internal curing effects. The synergistic effect of these two factors significantly reduces the shrinkage of the white ultra-high performance concrete spraying material used for surface decoration. In addition, during the preparation of the shrinkage-reducing components, the white sulfoaluminate cement is changed from directly participating in the hydration reaction to participating in the hydration reaction indirectly and slowly. This avoids the problem of excessively fast setting time and significantly shortened construction time of the ultra-high performance concrete spraying material due to the addition of white sulfoaluminate cement. It also avoids the problem of high-alumina bauxite aggregate directly absorbing a large amount of water during the mixing process, which would lead to increased slurry viscosity and poor workability and construction performance.

[0019] 3. The low-shrinkage surface decorative white ultra-high performance concrete spray material prepared by this invention has a low shrinkage rate, with a drying shrinkage of less than -90με after 180 days. It has excellent volume stability and can effectively prevent cracks from forming on the surface of the surface decorative white ultra-high performance concrete. It also has excellent durability and workability. Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] It should be noted that, in the description of the embodiments of this application, the term "some specific embodiments" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or instance. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] This invention provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material, comprising the following components by weight: 700-800 parts white cement, 130-160 parts white silica fume, 120-150 parts quartz powder, 15-25 parts titanium dioxide, 650-750 parts shrinkage reducing agent, 600 parts white quartz sand, 1-1.5 parts defoamer, 8-12 parts polycarboxylate superplasticizer, and 200-220 parts water; the shrinkage reducing agent is obtained by ultrasonic mixing and drying of high-alumina bauxite aggregate and finely ground white sulfoaluminate cement in a mass ratio of 1:(0.1-0.15) in a silane coupling agent.

[0023] Furthermore, the shrinkage-reducing component is prepared by the following method: high-alumina bauxite aggregate and finely ground white sulfoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15), and a silane coupling agent with a mass concentration of 5% to 8% is added and ultrasonically mixed for 10 to 15 minutes, and then dried to obtain the shrinkage-reducing component.

[0024] In some specific embodiments, the alumina content of the high-alumina bauxite aggregate is not less than 80 wt%, the particle size is 0-1 mm, and the white sulfoaluminate cement is grade 62.5 with a whiteness ≥85% and a fineness not greater than 600 mesh.

[0025] In some specific embodiments, the white cement is PW.52.5 white silicate cement with a whiteness ≥87%.

[0026] In some specific embodiments, the specific surface area of ​​the white silica fume is ≥15000 m². 2 / kg, 28d activity index ≥100%, whiteness ≥85%, SiO2 mass content ≥95%.

[0027] In some specific embodiments, the quartz powder has a fineness of no more than 300 mesh and a whiteness of ≥90%.

[0028] In some specific embodiments, the titanium dioxide is rutile type with a whiteness ≥95%, and the white quartz sand is 40-80 mesh with a fineness modulus of 1.4 to 1.8.

[0029] In some specific embodiments, the defoamer is an organosilicon defoamer or a polyether defoamer, and the water reduction rate of the polycarboxylate superplasticizer is ≥25%.

[0030] The preparation method of the above-mentioned low-shrinkage surface decorative white ultra-high performance concrete spraying material is as follows: high-alumina bauxite aggregate and finely ground white sulfoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15), and 5%-8% silane coupling agent is added and ultrasonically mixed for 10-15 minutes. After drying, the shrinkage-reducing component is obtained. Then, the formula amount of white cement, white silica fume, quartz powder, titanium dioxide, shrinkage-reducing component, white quartz sand and defoamer are placed in a mixer and stirred evenly for 4-6 minutes. While stirring, the formula amount of polycarboxylate superplasticizer and water are added and stirred for 6-10 minutes until the mixture is uniform, thus obtaining the low-shrinkage surface decorative white ultra-high performance concrete spraying material.

[0031] Based on the above embodiments, the present invention provides the following specific examples to further illustrate the invention. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following examples, unless otherwise specified, are generally performed according to the manufacturer's recommended conditions. Unless otherwise stated, percentages and parts are calculated by mass.

[0032] The white cement used is PW.52.5 white silicate cement with a whiteness of 88%.

[0033] The specific surface area of ​​white silica fume is 16500 m². 2 / kg, 28d activity index 125%, whiteness 90%, SiO2 mass content 95%;

[0034] The quartz powder is 300 mesh with a whiteness of 90%.

[0035] The titanium dioxide is of the rutile type, with a whiteness of 97%.

[0036] The alumina content of the high-alumina bauxite aggregate is not less than 80 wt%, and the particle size is 0-1 mm.

[0037] The white sulfoaluminate cement is grade 62.5 with a whiteness of 85%. The fineness of the white sulfoaluminate cement is ground to 600 mesh.

[0038] The mass concentration of the silane coupling agent is 7%.

[0039] White quartz sand has a mesh size of 40-80 and a fineness modulus of 1.6.

[0040] The defoamer is a polyether defoamer;

[0041] The water reduction rate of polycarboxylate superplasticizer is 25%;

[0042] The water is ordinary tap water.

[0043] Example 1

[0044] This embodiment provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material, which, by weight, includes the following components: 700 parts white cement, 150 parts white silica fume, 150 parts quartz powder, 25 parts titanium dioxide, 750 parts shrinkage reducing component, 600 parts white quartz sand, 1 part defoamer, 12 parts polycarboxylate superplasticizer, and 200 parts water.

[0045] The shrinkage-reducing component is obtained by mixing high-alumina bauxite aggregate and finely ground white sulfoaluminate cement at a mass ratio of 1:0.1, adding silane coupling agent, ultrasonically mixing for 12 minutes, and then drying.

[0046] The aforementioned low-shrinkage surface decorative white ultra-high performance concrete spray material is prepared by the following method:

[0047] Place the white cement, white silica fume, quartz powder, titanium dioxide, shrinkage reducing agent, white quartz sand and defoamer in a mixer and mix evenly for 5 minutes. While mixing, add the polycarboxylate superplasticizer and water in the same amount and mix for 10 minutes until the mixture is uniform, to obtain a low-shrinkage surface decorative white ultra-high performance concrete spray material.

[0048] Example 2

[0049] This embodiment provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material, which, by weight, includes the following components: 750 parts white cement, 140 parts white silica fume, 130 parts quartz powder, 20 parts titanium dioxide, 700 parts shrinkage reducing component, 600 parts white quartz sand, 1.5 parts defoamer, 10 parts polycarboxylate superplasticizer, and 220 parts water.

[0050] The shrinkage-reducing component is obtained by mixing high-alumina bauxite aggregate and finely ground white sulfoaluminate cement at a mass ratio of 1:0.13, adding silane coupling agent, ultrasonically mixing for 14 minutes, and then drying.

[0051] The aforementioned low-shrinkage surface decorative white ultra-high performance concrete spray material is prepared by the following method:

[0052] Place the white cement, white silica fume, quartz powder, titanium dioxide, shrinkage reducing agent, white quartz sand and defoamer in a mixer and mix evenly for 6 minutes. While mixing, add the polycarboxylate superplasticizer and water in the same amount and mix for 8 minutes until the mixture is uniform, to obtain a low-shrinkage surface decorative white ultra-high performance concrete spraying material.

[0053] Example 3

[0054] This embodiment provides a low-shrinkage surface decorative white ultra-high performance concrete spraying material, which, by weight, includes the following components: 800 parts white cement, 130 parts white silica fume, 120 parts quartz powder, 15 parts titanium dioxide, 750 parts shrinkage reducing component, 600 parts white quartz sand, 1.2 parts defoamer, 8 parts polycarboxylate superplasticizer, and 200 parts water.

[0055] The shrinkage-reducing component is obtained by mixing high-alumina bauxite aggregate and finely ground white sulfoaluminate cement at a mass ratio of 1:0.15, adding silane coupling agent, ultrasonically mixing for 15 minutes, and then drying.

[0056] The aforementioned low-shrinkage surface decorative white ultra-high performance concrete spray material is prepared by the following method:

[0057] Place the white cement, white silica fume, quartz powder, titanium dioxide, shrinkage reducing agent, white quartz sand and defoamer in a mixer and mix evenly for 6 minutes. While mixing, add the polycarboxylate superplasticizer and water in the same amount and mix for 8 minutes until the mixture is uniform, to obtain a low-shrinkage surface decorative white ultra-high performance concrete spraying material.

[0058] Comparative Example

[0059] The difference between this comparative example and Example 1 is that the shrinkage component in this comparative example is obtained by mixing high-alumina bauxite aggregate and unground white sulfoaluminate cement in a concrete mixer at a mass ratio of 1:0.1 for 10 minutes.

[0060] The following performance tests are used to further illustrate the beneficial effects of the low-shrinkage surface decorative white ultra-high performance concrete spraying material of the present invention.

[0061] Performance testing:

[0062] The low-shrinkage surface decorative white ultra-high performance concrete spraying materials of Examples 1-3 and Comparative Example 1 were tested for whiteness, fluidity, viscosity, initial crack resistance, 28-day compressive strength, water absorption, 28-day flexural strength, 28-day chloride ion permeability coefficient, freeze-thaw resistance, 7-day auto-shrinkage and 180-day drying shrinkage.

[0063] The initial crack resistance test method is as follows: a low-shrinkage surface decorative white ultra-high performance concrete spray material is sprayed onto a 200mm*200mm wooden board with a spray thickness of 2-3mm. The board is then immediately placed in a dry crack resistance tester for testing, and the surface of the specimen is monitored for 6 hours to see if cracks appear.

[0064] The performance test items and specific test results are shown in Tables 1 and 2.

[0065] Table 1. Test results of workability and mechanical properties of low-shrinkage surface decorative white ultra-high performance concrete spraying materials in Examples 1-3 and Comparative Examples.

[0066]

[0067] Table 2 shows the test results of the durability and volume stability of the low-shrinkage surface decorative white ultra-high performance concrete sprayed materials used in Examples 1-3 and the comparative examples.

[0068]

[0069] As can be seen from the results in Tables 1 and 2, the low-shrinkage surface decorative white ultra-high performance concrete spraying material of the present invention has excellent workability, construction performance, mechanical properties and durability. At the same time, its 180-day drying shrinkage is less than -90με, with low shrinkage rate, good crack resistance and good volume stability.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low shrinkage finish coat decorative white ultra-high performance concrete spray material, characterized in that, The white cement, white silica ash, quartz powder, titanium white powder, shrinkage-reducing component, white quartz sand, defoaming agent, polycarboxylic acid water reducer and water are mixed in the proportions of 700-800 parts, 130-160 parts, 120-150 parts, 15-25 parts, 650-750 parts, 600 parts, 1-1.5 parts, 8-12 parts and 200-220 parts respectively. The shrinkage-reducing component is obtained by mixing high-alumina bauxite aggregate and ground white sulphoaluminate cement in a silane coupling agent at a mass ratio of 1:(0.1-0.15) and drying.

2. The low shrinkage finish decorative white ultra high performance concrete spray material according to claim 1, characterized in that, The shrinkage-reducing component is obtained by the following method: The high-alumina bauxite aggregate and ground white sulphoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15) and added into a silane coupling agent with a mass concentration of 5%-8% for ultrasonic mixing for 10-15 minutes and drying to obtain the shrinkage-reducing component.

3. The low shrinkage finish decorative white ultra-high performance concrete spray material of claim 2, wherein, The high-alumina bauxite aggregate has an alumina content of not less than 80 wt%, and a particle size of 0-1 mm; the white sulphoaluminate cement is of grade 62.5, has a whiteness of not less than 85% and a fineness of not more than 600 mesh.

4. The low shrinkage finish decorative white ultra high performance concrete spray material of claim 1, wherein, The white cement is PW.52.5 white portland cement, and has a whiteness of not less than 87%.

5. The low shrinkage finish decorative white ultra high performance concrete spray material of claim 1, wherein, The specific surface area of the white silica ash is ≥ 15000 m 2 / kg, 28d activity index ≥ 100%, whiteness ≥ 85%, SiO2 mass content ≥ 95%.

6. The low shrinkage finish decorative white ultra-high performance concrete spray material of claim 1, wherein, The quartz powder has a fineness of not more than 300 mesh and a whiteness of not less than 90%.

7. The low shrinkage finish decorative white ultra high performance concrete spray material of claim 1, wherein, The titanium white powder is of rutile type, and has a whiteness of not less than 95%; the white quartz sand is of 40-80 mesh, and has a fineness modulus of 1.4-1.

8.

8. The low shrinkage finish decorative white ultra high performance concrete spray material of claim 1, wherein, The defoaming agent is a silicone defoaming agent or a polyether defoaming agent; the polycarboxylic acid water reducer has a water-reducing rate of not less than 25%.

9. Process for the preparation of a low shrinkage, deckled, white, super- high performance concrete sprayable material according to any one of claims 1 to 8, characterized in that, The high-alumina bauxite aggregate and ground white sulphoaluminate cement are mixed at a mass ratio of 1:(0.1-0.15) and added into a silane coupling agent with a mass concentration of 5%-8% for ultrasonic mixing for 10-15 minutes and drying to obtain the shrinkage-reducing component, then the white cement, white silica ash, quartz powder, titanium white powder, shrinkage-reducing component, white quartz sand and defoaming agent in the formula amount are placed in a mixer, uniformly stirred for 4-6 minutes, the polycarboxylic acid water reducer and water in the formula amount are added while stirring, and stirred for 6-10 minutes until uniform, to obtain the low-shrinkage surface layer decorative white ultra-high performance concrete spraying material.

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