Roller compacted concrete as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of concrete building materials, and particularly relates to hydropower station dam roller compacted concrete and a preparation method thereof. The roller compacted concrete disclosed by the embodiment of the invention comprises the following components in percentage by mass: 3.0%-4.1% of cement, 2.1%-2.4% of fly ash, 2.0%-2.3% of quartz rock micro powder, 28.0%-29.2% of fine aggregate, 59.6%-60.2% of coarse aggregate, 0.08% of a water reducing agent, 0.008%-0.01% of an air entraining agent and the balance of water. Wherein the quartz-an rock micro powder is a powdery admixture formed by grinding quartz-an rock aggregate. According to the roller compacted concrete, the Inan rock micro powder is used as an admixture, various performance requirements of design are met, meanwhile, the early-stage anti-cracking performance of the roller compacted concrete in the high-cold and high-altitude areas of the Tibetan area is improved, the anti-freezing performance, the anti-seepage performance and the like of the design are achieved, and the problem of insufficient supply of coal ash in the Tibetan area is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a roller-compacted concrete and its preparation method and application. Background Art

[0002] Roller-compacted concrete is a dry and lean-cement concrete, which is prepared by mixing portland cement, pozzolanic admixture, admixture, water, fine aggregate and coarse aggregate into a dry concrete without slump, and its Vebe consistency is 2s - 15s. Roller-compacted concrete dams have the characteristics of low cement consumption, low concrete temperature rise, high late strength, few cracks, high impermeability grade, and the dam body can directly block water.

[0003] In the hydropower projects in the Tibetan areas located in alpine and high-altitude regions, when the roller-compacted concrete is under the long-term influence of water pressure, seepage pressure, strong sunlight radiation, and severe cold in winter, it is damaged by seepage and freeze-thaw, reducing its durability. Therefore, there is an urgent need to provide a roller-compacted concrete with resistance to strong radiation and high freeze-thaw durability. Summary of the Invention

[0004] The present invention is made based on the inventor's discovery and understanding of the following facts and problems:

[0005] At present, in the hydropower projects in the Tibetan areas, due to the long transportation distance of the fly ash manufacturers, there is a problem of insufficient fly ash supply. In addition, located in alpine and high-altitude regions, with strong sunlight radiation and large daily temperature differences, higher requirements are imposed on the crack resistance of roller-compacted concrete.

[0006] The present invention aims to solve at least to some extent the technical problems related to the lack of fly ash in the hydropower projects in the Tibetan areas and the roller-compacted concrete in the alpine and high-altitude regions of the Tibetan areas. For this reason, the embodiments of the present invention provide a roller-compacted concrete, which can improve the early strength and early crack resistance of the roller-compacted concrete while solving the problem of insufficient fly ash supply, reduce the risk of early cracking, and also improve the freeze-thaw and impermeability durability performance of the roller-compacted concrete in the later stage.

[0007] The first aspect of the present application provides a roller-compacted concrete, which, by mass percentage, includes 3.0% - 4.1% of cement, 2.1% - 2.4% of fly ash, 2.0% - 2.3% of dacite micro-powder, 28.0% - 29.2% of fine aggregate, 59.6% - 60.2% of coarse aggregate, 0.08% of water-reducing agent, 0.008% - 0.01% of air-entraining agent, and the balance is water. Among them, the dacite micro-powder is a powdery admixture ground from dacite aggregate.

[0008] According to some embodiments of the roller-compacted concrete described in the present application, the cement is low-heat portland 42.5 cement, and the fineness of the cement is 300 - 350m 2 / kg.

[0009] According to some embodiments of the roller-compacted concrete described in the present application, the fly ash grade is Class F, Grade II, and the particle fineness of the fly ash is such that the residue on a 45μm square-hole sieve is 15%-25%.

[0010] According to some embodiments of the roller-compacted concrete described in the present application, the particle fineness of the dacite powder is such that the residue on a 45μm square-hole sieve is 10%-20%.

[0011] According to some embodiments of the roller-compacted concrete described in the present application, the fine aggregate is artificial sand ground from dacite aggregate, the fineness modulus of the artificial sand is 2.4-2.8, and the particle size of the artificial sand is 0.16-5mm.

[0012] According to some embodiments of the roller-compacted concrete described in the present application, the coarse aggregate is artificial crushed stone ground from dacite aggregate, and the artificial crushed stone includes small stones with a particle size of 5-20mm, medium stones with a particle size of 20-40mm, and large stones with a particle size of 40-80mm.

[0013] According to some embodiments of the roller-compacted concrete described in the present application, the water reducer is a naphthalene-based water reducer.

[0014] According to some embodiments of the roller-compacted concrete described in the present application, the air-entraining agent is a rosin resin-based air-entraining agent.

[0015] The second aspect of the present application provides a method for preparing the roller-compacted concrete described in the first aspect of the present application, including the following steps: mixing cement, fly ash, dacite powder, fine aggregate and coarse aggregate to obtain a mixture; adding a water reducer, an air-entraining agent and water to the mixture, and then mixing and stirring.

[0016] The third aspect of the present application provides an application of the roller-compacted concrete described in the first aspect of the present application or the roller-compacted concrete obtained by the preparation method described in the second aspect of the present application in the field of hydropower and water conservancy projects in Tibetan areas.

[0017] The beneficial effects of the present application are as follows: The roller-compacted concrete described in the present application has good early strength while meeting the strength requirements, improves the early crack resistance performance, reduces the risk of early cracking of concrete, and reduces the dosage of fly ash, solving the problem of insufficient fly ash supply in hydropower projects in Tibetan areas, and ensuring the frost resistance, impermeability and durability of concrete, which is convenient for popularization and application in hydropower projects in Tibetan areas. Specific Embodiments

[0018] The following details the embodiments of the present invention. The examples of the embodiments are exemplary and are intended to explain the present invention, but should not be construed as a limitation of the present invention.

[0019] In the present invention, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0020] An embodiment of the present application provides a roller compacted concrete, which, by mass percentage, includes 3.0%-4.1% of cement, 2.1%-2.4% of fly ash, 2.0%-2.3% of dacite fine powder, 28.0%-29.2% of fine aggregate, 59.6%-60.2% of coarse aggregate, 0.08% of water reducing agent, 0.008%-0.01% of air entraining agent, and the balance is water.

[0021] In some embodiments of the present application, the cement is low heat Portland 42.5 cement.

[0022] In some embodiments of the present application, the fineness of the cement is 300-350 m 2 / kg, such as 300 m 2 / kg, 320 m 2 / kg, 330 m 2 / kg, 350 m 2 / kg, etc.

[0023] In some embodiments of the present application, the fly ash grade is class F II, and the particle fineness of the fly ash is 15%-25% of the residue on a 45μm square hole sieve, such as 15%, 18%, 20%, 23%, 25%, etc.

[0024] In some embodiments of the present application, the dacite fine powder is a powdered admixture ground from dacite aggregate.

[0025] In some embodiments of the present application, the particle fineness of the dacite fine powder is 10%-20% of the residue on a 45μm square hole sieve, such as 10%, 12%, 15%, 18%, 20%, etc.

[0026] In some embodiments of the present application, the fine aggregate is artificial sand ground from dacite aggregate. The fineness modulus of the artificial sand is 2.4-2.8, and the particle size of the artificial sand is 0.16-5 mm, such as 0.16 mm, 0.315 mm, 0.63 mm, 1.25 mm, 2.5 mm, 5 mm, etc.

[0027] In some embodiments of the present application, the coarse aggregate is artificial crushed stone ground from dacite aggregate, and the artificial crushed stone includes small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm, and large stones with a particle size of 40 - 80 mm.

[0028] In some embodiments of the present application, the water reducing agent is a naphthalene-based water reducing agent, that is, naphthalene sulfonate formaldehyde condensate.

[0029] In some embodiments of the present application, the air-entraining agent is a rosin resin-based air-entraining agent.

[0030] The embodiments of the present application also provide a method for preparing the roller compacted concrete described in the first aspect of the present application, including the following steps: mixing cement, fly ash, dacite micro powder, fine aggregate and coarse aggregate to obtain a mixture; adding a water reducing agent, an air-entraining agent and water to the mixture, and then mixing and stirring.

[0031] The embodiments of the present application also provide an application of the roller compacted concrete described in the first aspect of the present application or the roller compacted concrete obtained by the preparation method described in the second aspect of the present application in the hydropower projects in Tibetan areas.

[0032] The technical solutions of the present application will be further described below with specific embodiments.

[0033] Example 1

[0034] A kind of roller compacted concrete, including raw materials in the following mass percentages: low heat Portland 42.5 cement with a fineness of 320 m 2 / kg, 4.1%, fly ash 2.1%, dacite micro powder 2.1%, fine aggregate 28.0%, coarse aggregate 60.2%, water reducing agent 0.08%, air-entraining agent 0.01%, and the balance is water;

[0035] The fly ash used in this example is Class F Grade II, and the particle fineness of the fly ash is 15% - 25% of the residue on a 45μm square hole sieve;

[0036] The particle fineness of the dacite micro powder used in this example is 10% - 20% of the residue on a 45μm square hole sieve;

[0037] The fine aggregate used in this example is artificial sand ground from dacite aggregate, with a fineness modulus of 2.4 - 2.8 and a particle size of 0.16 - 5 mm;

[0038] The coarse aggregate used in this example is artificial crushed stone ground from dacite aggregate, including small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm, and large stones with a particle size of 40 - 80 mm;

[0039] The water reducing agent used in this example is a naphthalene-based water reducing agent;

[0040] The air-entraining agent used in this embodiment is a rosin resin-based air-entraining agent.

[0041] The preparation method of the roller-compacted concrete described in Example 1 includes the following steps: First, dry-mix cement, fly ash, dacite powder, fine aggregate, and coarse aggregate in a mixer according to the designed ratio, and then add a water-reducing agent, an air-entraining agent, and water, and mix and stir them.

[0042] Example 2

[0043] The difference between the roller-compacted concrete described in Example 2 and that in Example 1 is only that the mass percentages of the raw materials contained in the roller-compacted concrete described in Example 2 are different from those in Example 1.

[0044] Specifically:

[0045] A kind of roller-compacted concrete, including raw materials in the following mass percentages: low-heat portland cement 42.5 with a fineness of 320m 2 / kg 3.0%, fly ash 2.3%, dacite powder 2.3%, fine aggregate 29.2%, coarse aggregate 59.7%, water-reducing agent 0.08%, air-entraining agent 0.008%, and the balance is water.

[0046] The preparation method of the roller-compacted concrete described in Example 2 includes the following steps: First, dry-mix cement, fly ash, dacite powder, fine aggregate, and coarse aggregate in a mixer according to the designed ratio, and then add a water-reducing agent, an air-entraining agent, and water, and mix and stir them.

[0047] Example 3

[0048] The difference between the roller-compacted concrete described in Example 3 and that in Example 1 is only that the mass percentages of the raw materials contained in the roller-compacted concrete described in Example 3 are different from those in Example 1.

[0049] Specifically:

[0050] A kind of roller-compacted concrete, including raw materials in the following mass percentages: low-heat portland cement 42.5 with a fineness of 320m 2 / kg 3.5%, fly ash 2.4%, dacite powder 2.0%, fine aggregate 29.0%, coarse aggregate 59.6%, water-reducing agent 0.08%, air-entraining agent 0.009%, and the balance is water.

[0051] The preparation method of the roller-compacted concrete described in Example 3 includes the following steps: First, dry-mix cement, fly ash, dacite powder, fine aggregate, and coarse aggregate in a mixer according to the designed ratio, and then add a water-reducing agent, an air-entraining agent, and water, and mix and stir them.

[0052] Comparative Example 1

[0053] The difference between the roller-compacted concrete described in Comparative Example 1 and that in Example 1 is only that: the roller-compacted concrete described in Comparative Example 1 does not contain the raw material of dacite powder, and medium heat 42.5 cement is used instead of low heat Portland 42.5 cement.

[0054] Specifically:

[0055] A kind of roller-compacted concrete, comprising the following raw materials in mass percentage: 4.1% of medium heat 42.5 cement, 4.2% of fly ash, 28.0% of fine aggregate, 60.2% of coarse aggregate, 0.08% of water reducing agent, 0.01% of air entraining agent, and the balance is water.

[0056] The preparation method of the roller-compacted concrete described in Comparative Example 1 comprises the following steps: first dry-mix the cement, fly ash, fine aggregate and coarse aggregate in a mixer according to the designed ratio, and then add the water reducing agent, air entraining agent and water, and mix and stir them evenly.

[0057] Comparative Example 2

[0058] The difference between the roller-compacted concrete described in Comparative Example 2 and that in Example 2 is only that: the roller-compacted concrete described in Comparative Example 2 does not contain the raw material of dacite powder, and medium heat 42.5 cement is used instead of low heat Portland 42.5 cement.

[0059] Specifically:

[0060] A kind of roller-compacted concrete, comprising the following raw materials in mass percentage: 3.0% of medium heat 42.5 cement, 4.6% of fly ash, 29.2% of fine aggregate, 59.7% of coarse aggregate, 0.08% of water reducing agent, 0.008% of air entraining agent, and the balance is water.

[0061] The preparation method of the roller-compacted concrete described in Comparative Example 2 comprises the following steps: first dry-mix the cement, fly ash, fine aggregate and coarse aggregate in a mixer according to the designed ratio, and then add the water reducing agent, air entraining agent and water, and mix and stir them evenly.

[0062] Comparative Example 3

[0063] The difference between the roller-compacted concrete described in Comparative Example 3 and that in Example 3 is only that: the roller-compacted concrete described in Comparative Example 3 does not contain the raw material of dacite powder, and medium heat 42.5 cement is used instead of low heat Portland 42.5 cement.

[0064] Specifically:

[0065] A kind of roller-compacted concrete, comprising the following raw materials in mass percentage: 3.5% of medium heat 42.5 cement, 4.4% of fly ash, 29.0% of fine aggregate, 59.6% of coarse aggregate, 0.08% of water reducing agent, 0.009% of air entraining agent, and the balance is water.

[0066] The preparation method of the roller-compacted concrete described in Comparative Example 3 includes the following steps: First, dry-mix cement, fly ash, fine aggregate, and coarse aggregate in a mixer according to the designed ratio, and then add a water reducer, an air-entraining agent, and water, and mix and stir them.

[0067] Performance research on the roller-compacted concrete described in Examples 1-3 and Comparative Examples 1-3 of this application.

[0068] The research results are shown in Tables 1-3:

[0069] Table 1 Results of the strength, frost resistance, and impermeability durability of roller-compacted concrete

[0070]

[0071] Table 2 Results of the adiabatic temperature rise and deformation of roller-compacted concrete

[0072]

[0073] Table 3 Results of the early anti-cracking performance of roller-compacted concrete

[0074]

[0075] It can be seen from Tables 1-3 that:

[0076] (1) The early compressive strengths of the roller-compacted concrete described in Examples 1-3 of this application at 7 days and 28 days are slightly higher than those of the roller-compacted concrete described in Comparative Examples 1-3; the frost resistance and impermeability durability both meet the design requirements.

[0077] (2) The adiabatic temperature rise value of the roller-compacted concrete described in Examples 1-3 of this application at 28 days is lower than that of the roller-compacted concrete described in Comparative Examples 1-3; the autogenous volume deformation shrinkage value and dry shrinkage value of the roller-compacted concrete described in Examples 1-3 of this application are both lower than those of Comparative Examples 1-3.

[0078] (3) The results of the early anti-cracking tests carried out by 3 methods show that the total cracking area per unit area of the roller-compacted concrete described in Examples 1 and 3 of this application is less than that of Comparative Examples 1-3 (the less, the better); the cracking times of the concrete in Examples 1 and 3 are both later than those of Comparative Examples 1 and 3 (the later, the better).

[0079] (4) The above results show that the performance results of the concrete in Examples 1-3 of this application are all better than those of the roller-compacted concrete described in Comparative Examples 1-3.

[0080] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A roller compacted concrete, characterized in that, By mass percentage, it includes 3.0%-4.1% of cement, 2.1%-2.4% of fly ash, 2.0%-2.3% of dacite fine powder, 28.0%-29.2% of fine aggregate, 59.6%-60.2% of coarse aggregate, 0.08% of water reducing agent, 0.008%-0.01% of air entraining agent, and the balance is water.

2. The roller compacted concrete according to claim 1, wherein The cement is low-heat Portland 42.5 cement, and the fineness of the cement is 300 - 350 m 2 / kg.

3. The roller compacted concrete according to claim 1, wherein The fly ash is of Class F, Grade II, and the particle fineness of the fly ash is that the residue on a 45μm square hole sieve is 15%-25%.

4. The roller compacted concrete according to claim 1, characterized in that, The particle fineness of the dacite fine powder is that the residue on a 45μm square hole sieve is 10%-20%.

5. The roller-compacted concrete according to claim 1, wherein The fine aggregate is artificial sand ground from dacite aggregate. The fineness modulus of the artificial sand is 2.4-2.8, and the particle size of the artificial sand is 0.16-5mm.

6. The roller compacted concrete according to claim 1, wherein The coarse aggregate is artificial crushed stone ground from dacite aggregate. The artificial crushed stone includes small stones with a particle size of 5-20mm, medium stones with a particle size of 20-40mm, and large stones with a particle size of 40-80mm.

7. The roller-compacted concrete according to claim 1, wherein The water reducing agent is a naphthalene-based water reducing agent.

8. The roller compacted concrete according to claim 1, characterized in that, The air entraining agent is a rosin resin-based air entraining agent.

9. The preparation method of roller compacted concrete according to any one of claims 1-8, characterized in that, It includes the following steps: Mix cement, fly ash, dacite fine powder, fine aggregate and coarse aggregate to obtain a mixture; add a water reducing agent, an air entraining agent and water to the mixture, and then mix and stir.

10. Application of the roller compacted concrete according to any one of claims 1-8 or the roller compacted concrete obtained by the preparation method according to claim 9 in the hydropower and water conservancy projects in Tibetan areas.

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