Super-early-strength and ultrahigh-strength concrete for rapid repair engineering as well as preparation method and application thereof

Abstract

The invention relates to super-early-strength and ultrahigh-strength concrete for rapid repair engineering and a preparation method and application thereof. The preparation method comprises the following steps: weighing the following raw materials in parts by weight: 410 to 430 parts of sulphoaluminate cement, 25 to 35 parts of silica fume, 200 to 210 parts of slag powder, 825 to 840 parts of fine aggregate, 550 to 580 parts of coarse aggregate, 10 to 20 parts of water reducing agent, 3 to 3.5 parts of auxiliary retarder, 8 to 10 parts of coagulant, 0.5 to 1 part of defoaming agent, 0.07 to 0.09 part of thickening agent, 0 to 55 parts of steel fiber and 200 to 210 parts of water; the preparation method comprises the following steps: putting sulphoaluminate cement, silica fume, slag powder, fine aggregate, coarse aggregate, a water reducing agent, an auxiliary retarder, a coagulant, a defoaming agent and a thickening agent into a stirrer, and premixing to be uniform; adding 1 / 2-3 / 4 of total water into the stirrer at one time, and uniformly stirring; adding steel fibers into the stirrer; adding the rest water into the stirrer at one time, and continuously stirring; and after pouring is completed, a water spraying kettle is used for spraying water mist to the surface of the concrete for curing, and the concrete strength is enhanced to reach the expectation.

Description

Technical Field

[0001] The present disclosure relates to the fields of civil and transportation technologies, and more particularly to an ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects, its preparation method, and applications. Background Art

[0002] As one of the most widely used civil engineering materials today, concrete is an important part of the transportation system for constructing a convenient, smooth, efficient, and safe transportation planning network. However, during the long-term use of road and bridge pavements made of concrete, damage often occurs for various reasons, such as excessive vehicle loads, natural erosion, and human damage. To reduce the impact on road use, emergency repair projects are usually carried out so that the repaired pavement can reach a certain strength in a short time to ensure smooth traffic and driving safety.

[0003] In emergency repair projects, special concrete materials are usually required, which can meet the requirements of emergency repair projects to a certain extent. However, in the prior art, there are relatively large problems in aspects such as the mechanical properties, setting time, and durability of special concrete materials. Some emergency repair concretes usually use a large amount of special cements such as sulphoaluminate cement to ensure the mechanical properties within a few hours, and the price is high. To ensure the strength of hardened concrete, some components used in the mix ratio, such as salts like lithium chloride, potassium fluoride, and lithium carbonate, have defects such as corroding steel bars, being prone to salt precipitation, and poor long-term stability, which is not conducive to environmental protection and sustainable development.

[0004] In addition, during the implementation of emergency repair projects, the preparation process of concrete is also crucial. Traditional preparation processes usually require special mixers to ensure uniform mixing, which is particularly prominent in concretes with short setting times, poor fluidity, high cement consumption, and the use of steel fibers. Once the on-site conditions are difficult to meet, problems such as uneven mixing, material waste, and low production efficiency are easily induced, affecting the quality and performance of emergency repair concrete. Therefore, optimizing the preparation process of emergency repair concrete, improving production efficiency, and ensuring the quality and performance of concrete are also one of the hotspots and difficulties in technological breakthroughs. Summary of the Invention

[0005] In view of this, the main purpose of the present disclosure is to provide an ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects with stable mechanical properties, controllable setting time, excellent durability, and easy on-site implementation, as well as its preparation method and applications, to solve the problem that it is currently difficult to prepare ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects with extremely low cement consumption, extremely high supplementary cementitious material consumption, and conventional mixing equipment.

[0006] According to one aspect of the present disclosure, there is provided a method for preparing an ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects, comprising:

[0007] S1: Weigh the raw materials according to the following parts by weight: 410 - 430 parts of sulfoaluminate cement, 25 - 35 parts of silica fume, 200 - 210 parts of slag powder, 825 - 840 parts of fine aggregate, 550 - 580 parts of coarse aggregate, 10 - 20 parts of water reducing agent, 3 - 3.5 parts of auxiliary retarder, 8 - 10 parts of accelerator, 0.5 - 1 part of defoamer, 0.07 - 0.09 part of thickener, 0 - 55 parts of steel fiber, and 200 - 210 parts of water;

[0008] S2: Put the sulfoaluminate cement, silica fume, slag powder, fine aggregate, coarse aggregate, water reducing agent, auxiliary retarder, accelerator, defoamer and thickener in the raw materials into a mixer and premix until uniform;

[0009] S3: Add 1 / 2 - 3 / 4 of the total water consumption to the mixer at one time and stir until uniform;

[0010] S4: Add steel fiber to the mixer. The steel fiber has passed through a stainless - steel square - hole sieve to prevent the steel fiber from agglomerating;

[0011] S5: Add the remaining water to the mixer at one time and continue to stir to obtain ultra - early - strength and ultra - high - strength concrete for rapid repair engineering that can be used for pouring;

[0012] S6: Use the ultra - early - strength and ultra - high - strength concrete for rapid repair engineering for pouring. After pouring, use a watering can to spray water mist on the surface of the concrete for curing to enhance the concrete strength to reach the expected level.

[0013] According to the embodiments of the present disclosure, the sulfoaluminate cement described in step S1 is a cementitious material. The sulfoaluminate cement clinker includes, by mass percentage, 60 - 75% of anhydrous calcium sulfoaluminate, 10 - 30% of dicalcium silicate, and 2 - 8% of tetracalcium ferroaluminate.

[0014] According to the embodiments of the present disclosure, the silica fume and slag powder described in step S1 are auxiliary cementitious materials, wherein the silica fume has a silica content of ≥92%, and the slag powder is of S95 grade.

[0015] According to the embodiments of the present disclosure, the fine aggregate described in step S1 is quartz sand, including four particle - size fine aggregates. Specifically, by mass percentage: 26 - 28% of fine aggregate with a particle size of 10 - 20 mesh, 23 - 25% of fine aggregate with a particle size of 20 - 40 mesh, 30% - 32% of fine aggregate with a particle size of 40 - 70 mesh, and 17 - 19% of fine aggregate with a particle size of 70 - 140 mesh.

[0016] According to the embodiments of the present disclosure, the coarse aggregate described in step S1 uses a continuous gradation of crushed stone with a particle size of 3 - 5 mm.

[0017] According to an embodiment of the present disclosure, the water reducing agent described in step S1 is at least one of polycarboxylate superplasticizer, naphthalene series water reducing agent, anthracene series water reducing agent, and lignosulfonate water reducing agent.

[0018] According to an embodiment of the present disclosure, the auxiliary setting retarder described in step S1 is at least one of borax, boric acid, citric acid, sodium gluconate, or tartaric acid.

[0019] According to an embodiment of the present disclosure, the setting accelerator described in step S1 is calcium oxide with a purity of ≥90%; the defoaming agent described in step S1 is a polyether polymer compound; the thickening agent described in step S1 is a polymer compound such as cellulose; the steel fiber described in step S1 is at least one of straight or profiled steel fibers; the water described in step S1 is mixing water.

[0020] According to an embodiment of the present disclosure, the mixer described in step S2 is a forced mixer, and the time required for premixing is 2 - 3 minutes.

[0021] According to an embodiment of the present disclosure, the stirring time required in step S3 is 2 - 3 minutes.

[0022] According to an embodiment of the present disclosure, the aperture of the stainless - steel square - hole sieve described in step S4 is 8 mm - 10 mm, and the time for adding steel fibers is within 1 - 2 minutes.

[0023] According to an embodiment of the present disclosure, the time required for continuous stirring in step S5 is 1 - 2 minutes.

[0024] According to an embodiment of the present disclosure, spraying water mist on the concrete surface for curing using a watering can in step S6 means spraying water mist on the concrete surface every 3 - 5 minutes using a watering can. The curing time is calculated starting from the spraying moment, and the strength can reach the expected requirements after curing for 2.5 - 3 hours.

[0025] According to another aspect of the present disclosure, there is provided a super - early - strength and ultra - high - strength concrete for rapid repair engineering prepared by the described method.

[0026] According to still another aspect of the present disclosure, there is provided an application of the super - early - strength and ultra - high - strength concrete for rapid repair engineering prepared by the described method in bridge, tunnel, emergency repair of expressway, runway / apron repair of airport, post - earthquake emergency reinforcement of building structure, and emergency repair engineering of industrial device foundation.

[0027] The super - early - strength and ultra - high - strength concrete for rapid repair engineering provided by the present disclosure, its preparation method and application have the following beneficial effects compared with the prior art:

[0028] (1) The present disclosure uses an extremely low cement dosage, an extremely high supplementary cementitious material dosage, and conventional mixing equipment to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair projects, solving the problem that it is currently difficult to use an extremely low cement dosage, an extremely high supplementary cementitious material dosage, and conventional mixing equipment to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair projects. This is of great significance for improving the efficiency and quality of repair projects, reducing repair costs, protecting the environment, and promoting the development of the concrete field.

[0029] (2) In view of the characteristics of ultra-early-strength and ultra-high-strength concrete for rapid repair projects, based on reducing the cement dosage and increasing the usage of solid waste resources, the present disclosure uses an extremely low cement dosage and an extremely high supplementary cementitious material dosage to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair projects, realizing the large-scale application of green and low-carbon concrete.

[0030] (3) The innovative application of conventional commercially available admixtures and supplementary cementitious materials in the present disclosure achieves unexpected effects. For example, the technology of over-dosing water-reducing agents is used to adjust the setting time, and calcium oxide is used as a setting accelerator instead of an expansive agent, thereby ensuring the short-term mechanical properties of the concrete and realizing the efficient preparation and construction of ultra-early-strength and ultra-high-strength concrete for rapid repair projects.

[0031] (4) The present disclosure can prepare ultra-early-strength and ultra-high-strength concrete using conventional mixing equipment, and ensures the short-term and long-term mechanical properties of the concrete, providing a strong guarantee for the timeliness of rapid repair projects. At the same time, it reduces the personnel, equipment, and technical requirements of the construction party for the implementation work. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above-mentioned content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0033] Figure 1 A flowchart showing a method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0035] The terms used herein are for describing specific embodiments only and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0036] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0037] To solve the problem that it is currently difficult to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair projects using extremely low cement dosages, extremely high supplementary cementitious material dosages, and conventional mixing equipment, the present disclosure provides an ultra-early-strength and ultra-high-strength concrete for rapid repair projects, its preparation method, and its application.

[0038] As Figure 1 shown, Figure 1 The flowchart of the method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects according to an embodiment of the present disclosure is shown. The method includes the following steps:

[0039] S1: Weigh the raw materials according to the following parts by weight: 410 - 430 parts of sulfoaluminate cement, 25 - 35 parts of silica fume, 200 - 210 parts of slag powder, 825 - 840 parts of fine aggregate, 550 - 580 parts of coarse aggregate, 10 - 20 parts of water reducer, 3 - 3.5 parts of auxiliary retarder, 8 - 10 parts of accelerator, 0.5 - 1 part of defoamer, 0.07 - 0.09 part of thickener, 0 - 55 parts of steel fiber, and 200 - 210 parts of water;

[0040] In this step, the sulfoaluminate cement is used as a cementitious material. The sulfoaluminate cement clinker includes 60 - 75% of anhydrous calcium sulfoaluminate, 10 - 30% of dicalcium silicate, and 2 - 8% of tetracalcium aluminoferrite by mass percentage. The sulfoaluminate cement mainly plays a cementing role, and its specific surface area is about 520 - 550 m 2 / kg. At this time, the anhydrous calcium sulfoaluminate in the sulfoaluminate cement has a relatively fast hydration rate and can hydrate to form ettringite to reach the expected strength in a short time (for example, within 3 h).

[0041] The silica fume and slag powder described above are supplementary cementitious materials. Among them, the silica fume has a silica content of ≥92%, and the slag powder is of S95 grade. In the existing public and conventional mix proportions of high-strength concrete, large amounts of highly reactive silica fume and small amounts of low-reactivity fly ash are usually used, respectively, to provide strength and reduce the heat of hydration, and slag powder is hardly used. In this disclosure, it is exactly the opposite of the prior art, which is one of the innovations. Small amounts of highly reactive silica fume are used to reduce the heat release during the hydration of silica fume, and the high reactivity of large amounts of slag powder is used to assist in strength improvement and ensure workability, and to guarantee the late strength and durability of the concrete.

[0042] The fine aggregate described above is quartz sand, including four particle sizes of fine aggregate. Specifically, by mass percentage: the fine aggregate with a particle size of 10 - 20 mesh is 26 - 28%, the fine aggregate with a particle size of 20 - 40 mesh is 23 - 25%, the fine aggregate with a particle size of 40 - 70 mesh is 30% - 32%, and the fine aggregate with a particle size of 70 - 140 mesh is 17 - 19%.

[0043] The coarse aggregate uses a continuous grading of crushed stone with a particle size of 3 - 5 mm.

[0044] The water-reducing agent used is at least one of polycarboxylate superplasticizer, naphthalene-based water-reducing agent, anthracene-based water-reducing agent, and lignosulfonate water-reducing agent. In the existing public and conventional mix proportions, the water-reducing agent is only used to disperse cement and mineral admixture particles to achieve the effect of reducing water consumption, and it is usually stipulated that the dosage of the water-reducing agent does not exceed 1% of the total cementitious material dosage to prevent excessive dosage from causing concrete setting retardation. However, this disclosure does the opposite. Exactly taking advantage of this characteristic of the water-reducing agent, a large amount of the water-reducing agent is used in the mix proportion, making the dosage of the water-reducing agent reach 2% - 5% of the total cementitious material dosage. The setting time of the concrete is controlled at 50 - 55 min by using the setting retardation effect of excessive addition of the water-reducing agent, ensuring sufficient time for pouring on-site, and at the same time assisting various admixtures to ensure early strength, achieving the purpose of preparing finished concrete with conventional mixing equipment.

[0045] The auxiliary setting retarder used is at least one of borax, boric acid, citric acid, sodium gluconate, or tartaric acid, which is used to further extend the setting time.

[0046] The accelerating agent described is calcium oxide with a purity of ≥90%. In existing public and conventional mix ratios, calcium sulfoaluminate cement, Portland cement, etc. are usually paired with anhydrous gypsum as an accelerating agent. However, in this disclosure, anhydrous gypsum is not used as an accelerating agent because the onset time of anhydrous gypsum is about 4 - 6 hours, far from achieving the purpose of ultra-early strength. In existing public and conventional mix ratios, calcium oxide is used as an expansive agent to compensate for the early plastic shrinkage of concrete. However, in this disclosure, calcium oxide is not used as an expansive agent but as an accelerating agent, which is completely different from the existing disclosure. This disclosure utilizes the exothermic characteristics during the hydration process of calcium oxide, which can rapidly increase the cement hydration rate within 1 hour after adding water and stirring, shorten the initial and final setting intervals of the cement, and enable the strength of the concrete to reach above 35 MPa within 2.5 - 3 hours. At the same time, the hydration of calcium oxide generates calcium hydroxide with strong alkalinity, which will undergo a secondary pozzolanic reaction with supplementary cementitious materials such as silica fume and slag, further enhancing the strength of the hardened concrete.

[0047] The defoaming agent described is a polyether-based polymer compound, which is used to eliminate the large air bubbles introduced into the concrete due to excessive addition of water-reducing agents, improve the compactness of the concrete, and thereby increase the strength of the concrete.

[0048] The thickening agent described is a polymer compound such as cellulose, which is used to improve the cohesiveness of fresh concrete and facilitate construction.

[0049] The steel fiber described is at least one of straight or profiled steel fibers.

[0050] The water described is mixing water.

[0051] S2: Put the calcium sulfoaluminate cement, silica fume, slag powder, fine aggregate, coarse aggregate, water-reducing agent, auxiliary setting retarder, accelerating agent, defoaming agent, and thickening agent in the raw materials into a mixer and premix until uniform.

[0052] In this step, the mixer used is a compulsory mixer, and the premixing time required is 2 - 3 minutes.

[0053] S3: Add 1 / 2 - 3 / 4 of the total water consumption to the mixer at one time and stir until uniform.

[0054] In this step, add 1 / 2 of the total water consumption to the mixer at one time and start stirring. After 1 minute, start slowly adding mixing water to the mixer continuously. The water addition time lasts for 0.5 - 1 minute. During this process, a total of 1 / 2 of the remaining water consumption is added, and then stir for 1.5 - 2 minutes until the state is uniform. Under this water consumption condition, it can prevent the concrete from having excessive fluidity and causing segregation or bleeding before adding steel fibers. The stirring time required is 2 - 3 minutes.

[0055] S4: Add steel fibers to the mixer. The steel fibers have passed through a stainless steel square-hole sieve to prevent the steel fibers from agglomerating.

[0056] In this step, the aperture of the stainless-steel square-hole sieve is 8 mm to 10 mm, and the time for adding steel fibers is within 1 to 2 minutes. Using the square-hole sieve can further simplify the steel fiber addition process and prevent steel fibers from agglomerating.

[0057] S5: Add the remaining water to the mixer at one time, and continue stirring to obtain ultra-early-strength and ultra-high-strength concrete for rapid repair projects that can be used for pouring;

[0058] In this step, the time required for the continuous stirring is 1 to 2 minutes.

[0059] S6: Use ultra-early-strength and ultra-high-strength concrete for rapid repair projects for pouring. After the pouring is completed, use a watering can to spray water mist on the concrete surface for curing to enhance the concrete strength to reach the expected level.

[0060] In this step, when using a watering can to spray water mist on the concrete surface for curing, spray water mist on the concrete surface with the watering can every 3 to 5 minutes. The curing time is calculated from the spraying moment. After curing for 2.5 to 3 hours, the strength can reach the expected requirements.

[0061] From Figure 1 the method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects shown in the embodiments, it can be seen that the method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects in the embodiments of the present disclosure has no special requirements for mechanical equipment throughout the preparation process, and the total stirring time is controlled within 7.5 to 10 minutes, which is beneficial to the requirements for timeliness in rapid repair projects. This technology is also one of the significant innovations of the present disclosure.

[0062] Based on Figure 1 the method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects according to the embodiments of the present disclosure shown, the following combines Examples 1-2 and Comparative Example 1 to detail the method for preparing ultra-early-strength and ultra-high-strength concrete for rapid repair projects provided by the present disclosure.

[0063] Example 1:

[0064] This example includes the following raw material components in parts by weight: 412 parts of sulfoaluminate cement, 26 parts of silica fume, 202 parts of slag powder, 828 parts of fine aggregate, 560 parts of coarse aggregate, 202 parts of water, 13 parts of water reducer, 3.5 parts of auxiliary retarder, 8 parts of accelerator, 0.5 part of defoamer, 0.07 part of thickener, and 40 parts of steel fiber.

[0065] Prepare the above raw materials according to Figure 1 the preparation method shown to obtain ultra-early-strength and ultra-high-strength concrete.

[0066] Example 2:

[0067] This embodiment includes the following raw material components in parts by weight: 425 parts of sulfoaluminate cement, 33 parts of silica fume, 209 parts of slag powder, 836 parts of fine aggregate, 575 parts of coarse aggregate, 208 parts of water, 18 parts of water reducer, 3.1 parts of auxiliary retarder, 10 parts of accelerator, 0.8 parts of defoamer, 0.08 parts of thickener, and 55 parts of steel fiber.

[0068] The above raw materials are prepared according to Figure 1 the preparation method shown to obtain ultra-early-strength and ultra-high-strength concrete.

[0069] Comparative Example 1:

[0070] This comparative example includes the following components in parts by weight: 750 parts of sulfoaluminate cement, 100 parts of slag powder, 100 parts of cenospheres, 620 parts of fine aggregate, 510 parts of coarse aggregate, 240 parts of water, 2 parts of water reducer, 2 parts of auxiliary retarder, 0.6 parts of defoamer, and 70 parts of steel fiber.

[0071] The above raw materials are prepared according to Figure 1 the preparation method shown to obtain ultra-early-strength and ultra-high-strength concrete.

[0072] Table 1 Physical and Mechanical Properties of Ultra-Early-Strength and Ultra-High-Strength Concrete in Examples and Comparative Examples

[0073]

[0074] It can be seen that the preparation method of ultra-early-strength and ultra-high-strength concrete for rapid repair engineering provided by the present disclosure uses extremely low cement dosage, extremely high dosage of auxiliary cementitious materials, and conventional mixing equipment to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair engineering, solving the problem that it is currently difficult to prepare ultra-early-strength and ultra-high-strength concrete for rapid repair engineering with extremely low cement dosage, extremely high dosage of auxiliary cementitious materials, and conventional mixing equipment. This is of great significance for improving the efficiency and quality of repair engineering, reducing repair costs, protecting the environment, and promoting the development of the concrete field.

[0075] Furthermore, the innovative application of conventional commercially available admixtures and auxiliary cementitious materials in the present disclosure achieves unexpected effects. For example, the technology of over-dosing water reducer is used to adjust the setting time, and calcium oxide is used as an accelerator instead of an expansive agent, thereby ensuring the short-term mechanical properties of the concrete and realizing the efficient preparation and construction of ultra-early-strength and ultra-high-strength concrete for rapid repair engineering.

[0076] Furthermore, the present disclosure can realize the preparation of ultra-early-strength and ultra-high-strength concrete using conventional mixing equipment, and ensure the short-term and long-term mechanical properties of the concrete, providing a strong guarantee for the timeliness of rapid repair engineering. At the same time, it reduces the personnel, equipment, and technical requirements of the construction party for the implementation work.

[0077] Furthermore, based on the above method for preparing ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects, the present disclosure also provides ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects prepared by using the method. This ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects is prepared by reducing the amount of cement used and increasing the amount of solid waste resources used, and is obtained by using an extremely low amount of cement and an extremely high amount of supplementary cementitious materials, realizing the large-scale application of green and low-carbon concrete.

[0078] Furthermore, based on the above method for preparing ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects, the present disclosure also provides the application of ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects prepared by using the method in bridge, tunnel, emergency repair of expressway, emergency repair of airport runway / apron, post-earthquake emergency reinforcement of building structures, and emergency repair projects of industrial plant foundations.

[0079] Those skilled in the art can understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0080] The embodiments of the present disclosure have been described above. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A preparation method of ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects, characterized in that, Including: S1: Weigh the raw materials according to the following parts by weight: 410 - 430 parts of sulfoaluminate cement, 25 - 35 parts of silica fume, 200 - 210 parts of slag powder, 825 - 840 parts of fine aggregate, 550 - 580 parts of coarse aggregate, 10 - 20 parts of water reducer, 3 - 3.5 parts of auxiliary retarder, 8 - 10 parts of accelerator, 0.5 - 1 part of defoamer, 0.07 - 0.09 part of thickener, 0 - 55 parts of steel fiber, and 200 - 210 parts of water; S2: Put the sulfoaluminate cement, silica fume, slag powder, fine aggregate, coarse aggregate, water reducer, auxiliary retarder, accelerator, defoamer, and thickener in the raw materials into a mixer and premix until uniform; S3: Add 1 / 2 - 3 / 4 of the total water consumption to the mixer at one time and stir until uniform; S4: Add steel fiber to the mixer. The steel fiber has passed through a stainless - steel square - hole sieve to prevent the steel fiber from agglomerating; S5: Add the remaining water to the mixer at one time, and continue to stir to obtain ultra - early - strength and ultra - high - strength concrete for rapid repair engineering that can be used for pouring; S6: Use the ultra - early - strength and ultra - high - strength concrete for rapid repair engineering for pouring. After pouring is completed, use a watering can to spray water mist on the surface of the concrete for curing to enhance the concrete strength to reach the expected level.

2. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, wherein, The sulfoaluminate cement described in step S1 is a gelling material. The sulfoaluminate cement clinker includes 60 - 75% of anhydrous calcium sulfoaluminate, 10 - 30% of dicalcium silicate, and 2 - 8% of tetracalcium ferroaluminate by mass percentage.

3. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The silica fume and slag powder described in step S1 are auxiliary gelling materials. Among them, the silica fume has a silica content of ≥92%, and the slag powder is of S95 grade.

4. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The fine aggregate described in step S1 is quartz sand, including four particle - size fine aggregates. Specifically, by mass percentage: 26 - 28% of fine aggregate with a particle size of 10 - 20 mesh, 23 - 25% of fine aggregate with a particle size of 20 - 40 mesh, 30% - 32% of fine aggregate with a particle size of 40 - 70 mesh, and 17 - 19% of fine aggregate with a particle size of 70 - 140 mesh.

5. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The coarse aggregate described in step S1 uses continuous grading of crushed stones with a particle size of 3 - 5 mm.

6. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The water reducer described in step S1 uses at least one of polycarboxylate superplasticizer, naphthalene - based water reducer, anthracene - based water reducer, and lignosulfonate water reducer.

7. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The auxiliary retarder described in step S1 uses at least one of borax, boric acid, citric acid, sodium gluconate, or tartaric acid.

8. The preparation method of the ultra - early - strength and ultra - high - strength concrete for rapid repair engineering according to claim 1, characterized in that The accelerator described in step S1 is calcium oxide with a purity of ≥90%; The defoamer described in step S1 is a polyether - type polymer compound; The thickener described in step S1 is a polymer compound such as cellulose; The steel fiber described in step S1 is at least one of straight - type or profiled steel fiber; The water described in step S1 is mixing water.

9. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The mixer described in step S2 uses a compulsory mixer, and the premixing time required is 2 - 3 min.

10. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The stirring time described in step S3 is 2 - 3 min.

11. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, The aperture of the stainless - steel square - hole sieve described in step S4 is 8 mm - 10 mm, and the time for adding steel fiber is within 1 - 2 min.

12. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, wherein, The required time for continuous stirring described in step S5 is 1 to 2 minutes.

13. The preparation method of the ultra-early-strength and ultra-high-strength concrete for rapid emergency repair projects according to claim 1, characterized in that, In step S6, spraying water mist on the concrete surface for curing using a watering can means spraying water mist on the concrete surface every 3 to 5 minutes. The curing time is calculated starting from the spraying moment, and the strength can reach the expected requirements after curing for 2.5 to 3 hours.

14. A super-early-strength and ultra-high-strength concrete for rapid repair engineering prepared by the method according to any one of claims 1 to 13.

15. Application of a super-early-strength and ultra-high-strength concrete for rapid repair engineering prepared by the method according to any one of claims 1 to 13 in bridge, tunnel, emergency repair of expressway, rush repair of airport runway / apron, emergency reinforcement of post-earthquake building structure, and rush repair engineering of industrial device base.

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