Lightweight high-strength concrete and preparation method therefor

Abstract

A lightweight high-strength concrete and a preparation method therefor. The lightweight high-strength concrete comprises a dry powder material and a liquid material, wherein the dry powder material comprises the following components in parts by weight: 490-515 parts of cement, 280-305 parts of mineral powders, 40-45 parts of silica fume, 300-320 parts of a first lightweight aggregate, 255-340 parts of a second lightweight aggregate and 0-200 parts of a crushed stone aggregate. The first lightweight aggregate has a first particle size specification, the second lightweight aggregate has a second particle size specification, and the second particle size specification is larger than the first particle size specification. The crushed stone aggregate has a third particle size specification which is larger than the first particle size specification. The liquid material comprises the following components in parts by weight: 200-240 parts of water and 4-10 parts of a water reducing agent. The lightweight high-strength concrete has both a low density and a high strength, and the flowability of a gelled slurry is improved. The preparation method may adopt either a lightweight aggregate pre-wetting process or a non-pre-wetting process.

Description

A lightweight high-strength concrete and its preparation method

[0001] manual

[0002] Cross-references

[0003] This application incorporates Chinese Patent Application No. 202411601207.4, filed on November 11, 2024, entitled “A Lightweight High-Strength Concrete and a Method for Preparing the Same”, which is incorporated herein by reference in its entirety. Technical Field

[0004] This application relates to the field of building materials technology, and more specifically to a lightweight, high-strength concrete and its preparation method. Background Technology

[0005] Concrete, a commonly used material in construction engineering, directly affects the safety and durability of projects due to its strength and quality. Traditional concrete has met the needs of engineering construction to a certain extent, but with the continuous development of prefabricated buildings, the demand for concrete that simultaneously possesses high strength and low density has become urgent, considering the actual needs of transporting and hoisting precast concrete components.

[0006] Most lightweight concrete currently on the market has relatively low strength in pursuit of lightweight properties. Furthermore, the production process for this type of lightweight concrete is cumbersome, requiring pre-wetting of lightweight aggregates and demanding high-quality equipment, which significantly limits its application in engineering projects.

[0007] Therefore, there is a need for a lightweight, high-strength concrete and its preparation method to at least partially solve the above problems. Summary of the Invention

[0008] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0009] To at least partially address the aforementioned problems, a first aspect of this application provides a lightweight high-strength concrete, comprising dry powder and liquid components.

[0010] The ratio of the dry powder is as follows:

[0011] Cement, 490–515 parts by weight

[0012] Mineral powder, 280-305 parts by weight

[0013] Silica fume, 40-45 parts by weight

[0014] The first lightweight aggregate, 300-320 parts by weight, has a first particle size specification.

[0015] The second lightweight aggregate, 255-340 parts by weight, has a second particle size distribution, which is larger than the first particle size distribution.

[0016] Crushed stone aggregate, 0-200 parts by weight, wherein the crushed stone aggregate has a third particle size specification.

[0017] The third particle size specification is larger than the first particle size specification;

[0018] The liquid mixture is prepared in the following proportions:

[0019] Water, 200-240 parts by weight

[0020] Water-reducing agent, 4-10 parts by weight.

[0021] The lightweight high-strength concrete according to this application has both low density and high strength, and the fluidity of the cement paste is improved by adjusting the amount of cement, mineral powder and silica fume. It can be used with both lightweight aggregate pre-wetting process and non-pre-wetting process, and has a wide range of applications.

[0022] Optionally, the first particle size specification is less than 5 mm.

[0023] Optionally, the second particle size specification is 5-10 mm; or

[0024] The second particle size specification is 5-20 mm.

[0025] Optionally, the third particle size specification is 5-10 mm; or

[0026] The third particle size specification is 5-20mm.

[0027] Optionally, the third particle size specification is the same as the second particle size specification.

[0028] Optionally, the apparent density of the first lightweight aggregate is 1100–1200 kg / m³. 3 The water absorption rate of the first lightweight aggregate is 8-9% over 1 hour.

[0029] Optionally, when the second particle size is 5-10 mm, the apparent density of the second lightweight aggregate is 1000-1100 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 6-7% in 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa.

[0030] When the second particle size is 5–20 mm, the apparent density of the second lightweight aggregate is 950–1050 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 5.5-6.5% over 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa.

[0031] Optionally, the first lightweight aggregate and / or the second lightweight aggregate may comprise lightweight shale aggregate.

[0032] Optionally, the cement grade is 52.5PII; and / or

[0033] The mineral powder is designated as S95; and / or

[0034] The water-reducing agent is a polycarboxylate water-reducing agent.

[0035] The second aspect of this application provides a preparation method for preparing the lightweight high-strength concrete described in the first aspect above, the preparation method comprising the following steps:

[0036] Steps for mixing dry powder materials;

[0037] Mixing liquid steps;

[0038] The step of forming a gelling paste involves mixing the dry powder and the liquid to form a gelling paste.

[0039] The pouring and curing steps involve pouring and curing the cementitious slurry to form the lightweight, high-strength concrete.

[0040] Optionally, a pre-wetting step is included before the mixing of dry powder, the pre-wetting step including: soaking the first lightweight aggregate and the second lightweight aggregate in water for a predetermined time and then surface drying;

[0041] The step of forming a gel slurry includes: adding the liquid material to the dry powder material all at once and stirring.

[0042] Optionally, the step of forming the gelling paste includes:

[0043] Take a portion of the liquid material and add it to the dry powder material for the first stirring;

[0044] Add the remaining liquid and stir a second time.

[0045] According to the preparation method of this application, lightweight aggregates can be pre-wetted or not, which has a wide range of applications, and the concrete produced has both low density and high strength characteristics. Detailed Implementation

[0046] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0047] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the said components, features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other components, features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0048] Ordinal numbers such as “first” and “second” used in this application are merely identifiers and have no other meaning, such as a specific order. Moreover, for example, the term “first component” does not imply the existence of a “second component”, and the term “second component” does not imply the existence of a “first component”.

[0049] The first aspect of this application provides a lightweight, high-strength concrete. It comprises a dry powder and a liquid component. The dry powder consists of 490-515 parts by weight of cement, 280-305 parts by weight of mineral powder, 40-45 parts by weight of silica fume, 300-320 parts by weight of a first lightweight aggregate, 255-340 parts by weight of a second lightweight aggregate, and 0-200 parts by weight of crushed stone aggregate. The first lightweight aggregate has a first particle size specification, the second lightweight aggregate has a second particle size specification, and the second particle size specification is larger than the first particle size specification. The crushed stone aggregate has a third particle size specification, and the third particle size specification is larger than the first particle size specification. The liquid component consists of 200-240 parts by weight of water and 4-10 parts by weight of a water-reducing agent.

[0050] The lightweight high-strength concrete according to this application has both low density and high strength characteristics, and the fluidity of the cement paste is improved by adjusting the amount of cement, mineral powder and silica fume. It can be used with both lightweight aggregate pre-wetting process and non-pre-wetting process, and has a wide range of applications.

[0051] The second particle size is larger than the first particle size, so the first lightweight aggregate can be called lightweight fine aggregate, and the second lightweight aggregate can be called lightweight coarse aggregate.

[0052] Specifically, the first particle size is less than 5 mm. That is, the particle size of the first lightweight aggregate is less than 5 mm. Preferably, the apparent density of the first lightweight aggregate is 1100-1200 kg / m³. 3 The first lightweight aggregate has a 1-hour water absorption rate of 8-9%. More preferably, the first lightweight aggregate is lightweight shale aggregate.

[0053] In one implementation, the second particle size is 5–10 mm. In this embodiment, the apparent density of the second lightweight aggregate is 1000–1100 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 6-7% in 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa.

[0054] Alternatively, the second particle size distribution may be 5–20 mm. In this embodiment, the apparent density of the second lightweight aggregate is 950–1050 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 5.5-6.5% over 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa.

[0055] The third particle size specification can be 5-10mm, or 5-20mm.

[0056] In a preferred embodiment, the third particle size is the same as the second particle size. That is, the particle size of both the second lightweight aggregate and the crushed stone aggregate is 5-10 mm, or the particle size of both the second lightweight aggregate and the crushed stone aggregate is 5-20 mm.

[0057] Preferably, the second lightweight aggregate can be lightweight shale aggregate.

[0058] In this implementation, the cement grade is 52.5PII. The mineral powder grade is S95. The water-reducing agent is a polycarboxylate water-reducing agent. More specifically, a high-efficiency polycarboxylate water-reducing agent is selected.

[0059] The second aspect of this application provides a preparation method for preparing the lightweight high-strength concrete described in the first aspect. The preparation method includes the following steps:

[0060] Steps for mixing dry powder materials.

[0061] Mixing liquid steps.

[0062] The step of forming a gelling paste involves mixing dry powder and liquid materials to form a gelling paste.

[0063] The pouring and curing process involves pouring and curing the cementitious slurry to form lightweight, high-strength concrete.

[0064] As one implementation method, the preparation method also includes a material preparation step. Since the technical specifications of lightweight aggregates are relatively difficult to control, after purchasing lightweight aggregates, it is necessary to measure key indicators such as density, saturated water absorption, 1-hour water absorption, and moisture content to ensure that the material quality is good and meets the requirements.

[0065] In addition, lightweight aggregates have a strong water absorption capacity and will "steal water" from the cementitious paste, which may lead to a faster loss of concrete slump. Furthermore, the water-cement ratio at the interface between lightweight aggregates and cementitious substrates is reduced. Although this may improve the bonding strength of the interface in the short term, it will increase the number of drying shrinkage cracks in the concrete and will not be conducive to the later strength increase.

[0066] Therefore, existing technologies often employ a pre-wetting lightweight aggregate process, which involves pre-soaking and wetting the lightweight aggregate. This prevents the lightweight aggregate from "stealing water" from the cement, thus improving the fluidity and workability of the concrete. At the same time, the moisture in the pre-wetted lightweight aggregate will have a water-returning effect on the slurry, making the bond between the lightweight aggregate and the cement paste more compact, and the later strength of the concrete will also be improved.

[0067] In one optional embodiment of this application, the preparation method may also employ a pre-wetting lightweight aggregate process; in other words, a pre-wetting step is included before the dry powder mixing step. The pre-wetting step includes soaking the first and second lightweight aggregates in water for a predetermined time and then surface drying them. The step of forming the gel slurry includes adding a portion of the liquid material to the dry powder for a first stirring, preferably for 1 minute. Then, the remaining liquid material is added for a second stirring, preferably for at least 2 minutes.

[0068] However, pre-wetting lightweight aggregates require specific machinery and equipment, and ordinary concrete mixing plants lack the conditions for pre-wetting lightweight aggregates. According to the lightweight high-strength concrete formula of this application, when conditions are insufficient, lightweight concrete meeting the design strength can still be obtained by using a non-pre-wetting lightweight aggregate preparation method. In other words, in the step of forming the cementitious paste, the liquid material is added to the dry powder material at one time and stirred, preferably for 1.5 to 2 minutes, so that the paste evenly coats the surface of the aggregate and has an oily gloss.

[0069] According to the preparation method of this application, lightweight aggregates can be pre-wetted or not, which has a wide range of applications, and the concrete produced has both low density and high strength.

[0070] The present application will now be described in more detail with reference to embodiments and comparative examples.

[0071] Example 1

[0072] Dry powder: 504 parts by weight of cement, 294 parts by weight of mineral powder, 42 parts by weight of silica fume, 310 parts by weight of the first lightweight aggregate with a size of 0-5mm, and 332 parts by weight of the second lightweight aggregate with a size of 5-10mm.

[0073] Liquid component: 228 parts by weight of water, 6.72 parts by weight of water-reducing agent.

[0074] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0075] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0076] Example 2

[0077] It is basically the same as Example 1, except that:

[0078] 7.56 parts by weight of water-reducing agent.

[0079] Example 3

[0080] It is basically the same as Example 1, except that:

[0081] 265 parts by weight of the second lightweight aggregate with a size of 5-10mm, and 193 parts by weight of crushed stone aggregate with a size of 5-10mm.

[0082] Example 4

[0083] It is basically the same as Example 3, except that the water-reducing agent is 7.56 parts by weight.

[0084] Example 5

[0085] Dry powder: 494 parts by weight of cement, 284 parts by weight of mineral powder, 42 parts by weight of silica fume, 320 parts by weight of the first lightweight aggregate with a size of 0-5mm, and 322 parts by weight of the second lightweight aggregate with a size of 5-20mm.

[0086] Liquid component: 218 parts by weight of water, 5.81 parts by weight of water-reducing agent.

[0087] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0088] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0089] Example 6

[0090] It is basically the same as Example 5, except that:

[0091] 255 parts by weight of the second lightweight aggregate with a size of 5-20mm, and 193 parts by weight of crushed stone aggregate with a size of 5-20mm.

[0092] Example 7

[0093] Dry powder: 490 parts by weight of cement, 280 parts by weight of mineral powder, 40 parts by weight of silica fume, 320 parts by weight of the first lightweight aggregate with a size of 0-5mm, and 340 parts by weight of the second lightweight aggregate with a size of 5-10mm.

[0094] Liquid component: 220 parts by weight of water, 6.48 parts by weight of water-reducing agent.

[0095] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0096] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0097] Example 8

[0098] It is basically the same as Example 7, except that:

[0099] 271 parts by weight of the second lightweight aggregate with a size of 5-10mm, and 200 parts by weight of crushed stone aggregate with a size of 5-10mm.

[0100] Example 9

[0101] It is basically the same as Example 7, except that:

[0102] 310 parts by weight of the first lightweight aggregate with a size of 0-5mm and 332 parts by weight of the second lightweight aggregate with a size of 5-10mm.

[0103] Example 10

[0104] It is basically the same as Example 9, except that:

[0105] 265 parts by weight of the second lightweight aggregate with a size of 5-10mm, and 193 parts by weight of crushed stone aggregate with a size of 5-10mm.

[0106] Example 11

[0107] Dry powder: 504 parts by weight of cement, 294 parts by weight of mineral powder, 42 parts by weight of silica fume, 300 parts by weight of the first lightweight aggregate with a size of 0-5mm, and 320 parts by weight of the second lightweight aggregate with a size of 5-10mm.

[0108] Liquid component: 228 parts by weight of water, 6.72 parts by weight of water-reducing agent.

[0109] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0110] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0111] Example 12

[0112] It is basically the same as Example 11, except that:

[0113] 256 parts by weight of the second lightweight aggregate with a size of 5-10mm, and 185 parts by weight of crushed stone aggregate with a size of 5-10mm.

[0114] Example 13

[0115] Dry powder: 515 parts by weight of cement, 305 parts by weight of mineral powder, 45 parts by weight of silica fume, 300 parts by weight of the first lightweight aggregate with a size of 0-5mm, and 320 parts by weight of the second lightweight aggregate with a size of 5-10mm.

[0116] Liquid component: 235 parts by weight of water, 6.92 parts by weight of water-reducing agent.

[0117] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0118] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0119] Example 14

[0120] It is basically the same as Example 13, except that:

[0121] 256 parts by weight of the second lightweight aggregate with a size of 5-10mm, and 185 parts by weight of crushed stone aggregate with a size of 5-10mm.

[0122] Comparative Example 1

[0123] Dry powder materials: 264 parts by weight of cement, 159 parts by weight of mineral powder, 738 parts by weight of sand with a size of 0-5mm, and 1063 parts by weight of crushed stone aggregate with a size of 5-20mm.

[0124] Liquid component: 160 parts by weight of water, 10.75 parts by weight of water-reducing agent.

[0125] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0126] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0127] Comparative Example 2

[0128] Dry powder materials: 413 parts by weight of cement, 60 parts by weight of fly ash, 726 parts by weight of sand with a size of 0-5mm, and 1061 parts by weight of crushed stone aggregate with a size of 5-20mm.

[0129] Liquid component: 165 parts by weight of water, 10.15 parts by weight of water-reducing agent.

[0130] The dry powder and liquid materials are mixed according to the above process steps to form a gel slurry, which is then poured and cured.

[0131] The concrete strength was tested after 3, 7, and 28 days of curing, and the dry apparent density was also tested.

[0132] The dosage of each component in Examples 1-14 is shown in Table 1 below.

[0133] Table 1

[0134] The amounts of each component in Comparative Examples 1-2 are shown in Table 2 below.

[0135] Table 2

[0136] The test results of Examples 1-14 and Comparative Examples 1-2 are shown in Table 3 below.

[0137] Table 3

[0138] As can be seen from Examples 1-14 and Comparative Examples 1-2 above, by changing the existing concrete, which uses all crushed stone aggregate, to partially using ordinary crushed stone aggregate and the remainder using lightweight aggregate, higher strength is achieved while reducing the density of the concrete. The lightweight aggregate high-strength concrete according to this application has a density between 1670 kg / m³ and 1750 kg / m³. By increasing the cement content, the fluidity of the fine stone concrete is improved while maintaining concrete strength.

[0139] Furthermore, the lightweight aggregate high-strength concrete according to this application can improve the workability of concrete and reduce costs by incorporating some mineral powder, which is beneficial to environmental protection and promotes sustainable development; by incorporating silica fume, the strength, durability and impermeability of concrete can be further improved, while its workability is also improved.

[0140] The processes and steps described in all the preferred embodiments above are merely examples. Unless adverse effects occur, various processing operations can be performed in a different order than the above-described processes. The order of steps in the above processes can also be added, combined, or deleted according to actual needs.

[0141] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application. Features described in one embodiment may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0142] This application has been described through the above embodiments. However, it should be understood that the above embodiments are only for illustrative purposes. This application is not limited to the above embodiments. Many variations and modifications can be made based on the teachings of this application, and all such variations and modifications fall within the scope of protection claimed in this application.

Claims

1. A lightweight, high-strength concrete, characterized in that, The lightweight high-strength concrete comprises dry powder and liquid components. The ratio of the dry powder is as follows: Cement, 490–515 parts by weight Mineral powder, 280-305 parts by weight Silica fume, 40-45 parts by weight The first lightweight aggregate, 300-320 parts by weight, has a first particle size specification. The second lightweight aggregate, 255-340 parts by weight, has a second particle size distribution, which is larger than the first particle size distribution. Crushed stone aggregate, 0 to 200 parts by weight, wherein the crushed stone aggregate has a third particle size specification, and the third particle size specification is larger than the first particle size specification; The liquid mixture is prepared in the following proportions: Water, 200-240 parts by weight Water-reducing agent, 4-10 parts by weight.

2. The lightweight high-strength concrete according to claim 1, characterized in that, The first particle size specification is less than 5mm.

3. The lightweight high-strength concrete according to claim 1, characterized in that, The second particle size specification is 5-10 mm; or The second particle size specification is 5-20 mm.

4. The lightweight high-strength concrete according to claim 1, characterized in that, The third particle size specification is 5-10mm; or The third particle size specification is 5-20mm.

5. The lightweight high-strength concrete according to claim 1, characterized in that, The third particle size specification is the same as the second particle size specification.

6. The lightweight high-strength concrete according to claim 2, characterized in that, The apparent density of the first lightweight aggregate is 1100–1200 kg / m³. 3 The water absorption rate of the first lightweight aggregate is 8-9% over 1 hour.

7. The lightweight high-strength concrete according to claim 3, characterized in that, When the second particle size is 5-10 mm, the apparent density of the second lightweight aggregate is 1000-1100 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 6-7% in 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa. When the second particle size is 5–20 mm, the apparent density of the second lightweight aggregate is 950–1050 kg / m³. 3 The water absorption rate of the second lightweight aggregate is 5.5-6.5% over 1 hour, and the compressive strength of the second lightweight aggregate is 2-3 MPa.

8. The lightweight high-strength concrete according to claim 1, characterized in that, The first lightweight aggregate and / or the second lightweight aggregate include lightweight shale aggregate.

9. The lightweight high-strength concrete according to claim 1, characterized in that, The cement grade is 52.5PII; and / or The mineral powder is designated as S95; and / or The water-reducing agent is a polycarboxylate water-reducing agent.

10. A preparation method for preparing lightweight high-strength concrete according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: Steps for mixing dry powder materials; Mixing liquid steps; The step of forming a gelling paste involves mixing the dry powder and the liquid to form a gelling paste. The pouring and curing steps involve pouring and curing the cementitious slurry to form the lightweight, high-strength concrete.

11. The preparation method according to claim 10, characterized in that, The process of mixing dry powder materials includes a pre-wetting step before the mixing dry powder material step. The pre-wetting step includes: soaking the first lightweight aggregate and the second lightweight aggregate in water for a predetermined time and then surface drying them. The step of forming a gel slurry includes: adding the liquid material to the dry powder material all at once and stirring.

12. The preparation method according to claim 10, characterized in that, The step of forming the gel slurry includes: Take a portion of the liquid material and add it to the dry powder material for the first stirring; Add the remaining liquid and stir a second time.

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