Full-age super-crack-resistant concrete for rapid repair as well as preparation method and application of full-age super-crack-resistant concrete

Abstract

The invention discloses full-age super-crack-resistant concrete for rapid repair and a preparation method and application of the full-age super-crack-resistant concrete. The preparation method comprises the following steps: weighing the following raw materials in parts by weight: 400 to 430 parts of a cementing material, 280 to 300 parts of an anti-cracking mixed material, 60 to 70 parts of an inert mixed material, 1450 to 1475 parts of fine aggregate, 8 to 10 parts of a water reducing agent, 3.1 to 3.6 parts of a retarder, 0.6 to 0.9 part of a defoaming agent, 0.08 to 0.1 part of a thickening agent, 115 to 130 parts of steel fibers, 0.7 to 1 part of organic fibers and 180 to 215 parts of water; the preparation method comprises the following steps: putting a cementing material, an anti-crack mixed material, a fine aggregate, a coarse aggregate, a water reducing agent, a retarder, a defoaming agent, a thickening agent and organic fibers into a stirrer, and premixing until the materials are uniform; adding 3 / 4 of the total water amount into the stirrer, 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 a full-age ultra-crack-resistant concrete for rapid repair, its preparation method and application. Background Art

[0002] During the long-term use of concrete materials for infrastructure, due to the influence of natural factors (such as weathering, erosion, freeze-thaw, etc.) and human factors (such as traffic loads, construction damage, etc.), damages such as cracks, leakage, and spalling often occur. These damages not only affect the aesthetics and functionality of the structure, but also may pose a threat to the safety of the structure. Therefore, it is crucial to repair the damaged parts in a timely and effective manner.

[0003] Rapid repair materials must possess the characteristics of rapid hardening, early strength, and stable long-term performance. However, the rapid repair materials used in the existing disclosures have problems such as early cracking during on-site implementation and cracking during long-term service. At the same time, the repaired structure still faces a complex stress environment, and ordinary concrete is difficult to meet the demand for crack resistance and is prone to secondary cracking.

[0004] Almost all of the existing disclosures use the method of compounding different types and sizes of fibers to improve the crack resistance of concrete. However, such methods usually can only solve the problem of drying shrinkage cracking of concrete during natural curing, perform poorly in solving the cracking problem of rapid hardening concrete caused by chemical shrinkage and plastic shrinkage at the early stage, and also contribute less to solving the cracking problem of long-age concrete caused by drying shrinkage, significantly affecting the overall durability of the structure.

[0005] Therefore, if the problem of full-age crack resistance of concrete materials for rapid repair projects can be solved, while not significantly increasing the cement consumption, not significantly increasing the cost, and not using special admixtures and shrinkage-reducing materials that affect mechanical properties, thereby preparing a full-age ultra-crack-resistant concrete for rapid repair, it is a better solution. Summary of the Invention

[0006] In view of this, the main object of the present disclosure is to provide a full-age ultra-crack-resistant concrete for rapid repair, its preparation method and application, so as to solve the problems of rapid setting and hardening, high-strength requirements, full-age crack resistance performance, full-life cycle impermeability performance, and long-term durability faced by concrete materials in rapid repair projects.

[0007] According to one aspect of the present disclosure, a preparation method of a full-age ultra-crack-resistant concrete for rapid repair is provided, including:

[0008] S1: Weigh the raw materials according to the following parts by weight: 400 - 430 parts of cementitious material, 280 - 300 parts of crack - resistant admixture, 60 - 70 parts of inert admixture, 1450 - 1475 parts of fine aggregate, 8 - 10 parts of water - reducing agent, 3.1 - 3.6 parts of retarder, 0.6 - 0.9 parts of defoamer, 0.08 - 0.1 parts of thickener, 115 - 130 parts of steel fiber, 0.7 - 1 part of organic fiber, and 180 - 215 parts of water;

[0009] S2: Put the cementitious material, crack - resistant admixture, fine aggregate, coarse aggregate, water - reducing agent, retarder, defoamer, thickener and organic fiber in the raw materials into a mixer and premix until uniform;

[0010] S3: Add 3 / 4 of the total water consumption to the mixer and stir until uniform;

[0011] 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;

[0012] S5: Add the remaining water to the mixer at one time and continue to stir to obtain all - age - period super - crack - resistant concrete for rapid repair;

[0013] S6: Use the all - age - period super - crack - resistant concrete for rapid repair for pouring. After pouring, use a watering can to spray water mist on the concrete surface for curing to enhance the concrete strength to reach the expected value.

[0014] According to the embodiments of the present disclosure, the cementitious material described in step S1 is sulfoaluminate cement. 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.

[0015] According to the embodiments of the present disclosure, the crack - resistant admixture described in step S1 is obtained by mixing silica fume, fly ash, slag powder and calcium oxide in a mass ratio of 1:5:6:0.35, where:

[0016] The silica fume has a silica content ≥ 95% and a specific surface area of 490 - 510m 2 / kg;

[0017] The fly ash is desulfurized secondary ash with a specific surface area of 300 - 390m 2 / kg;

[0018] The slag powder is of S95 grade with a specific surface area of 380 - 430m 2 / kg;

[0019] The calcium oxide is industrial - pure calcium oxide with a purity ≥ 90%.

[0020] According to an embodiment of the present disclosure, the inert admixture in step S1 is fly ash microspheres, with a specific surface area of 800 - 1050 m 2 / kg.

[0021] According to an embodiment of the present disclosure, the fine aggregate in step S1 is quartz sand, which is composed of four particle sizes of 10 - 20 mesh, 20 - 40 mesh, 40 - 70 mesh, and 70 - 140 mesh and mixed in a mass ratio of 4:5:6:3.

[0022] According to an embodiment of the present disclosure, the water reducing agent in step S1 is at least one of polycarboxylate superplasticizer, naphthalene-based water reducing agent, anthracene-based water reducing agent, and lignosulfonate water reducing agent.

[0023] According to an embodiment of the present disclosure, the setting retarder in step S1 is at least one of borax, boric acid, citric acid, sodium gluconate, or tartaric acid.

[0024] According to an embodiment of the present disclosure, the defoaming agent in step S1 is a polyether-based polymer compound; the thickening agent in step S1 is at least one of methyl cellulose, hydroxypropyl methyl cellulose ether, polyacrylamide, sodium polyacrylate, polyvinyl alcohol, xanthan gum, chitosan, gelatin, modified starch, and carboxymethyl cellulose ether polymer compounds; the steel fiber in step S1 is at least one of straight or profiled steel fibers; the organic fiber in step S1 is at least one of polypropylene (PP) fiber, polyvinyl alcohol (PVA) fiber, alkali-resistant glass fiber, and polyester fiber; the water in step S1 is mixing water.

[0025] According to an embodiment of the present disclosure, the mixer in step S2 is a forced mixer, and the required time for premixing is 2 - 3 min.

[0026] According to an embodiment of the present disclosure, adding 3 / 4 of the total water consumption to the mixer and stirring until uniform includes: adding 1 / 2 of the total water consumption to the mixer at one time, starting to stir, and then starting to slowly add mixing water to the mixer after 1 min. The water addition time lasts for 0.5 - 1 min, and a total of 1 / 2 of the remaining water consumption is added during this process. Then stir for 1.5 - 2 min until the state is uniform.

[0027] According to an embodiment of the present disclosure, the aperture of the stainless steel square hole sieve in step S4 is 8 mm - 10 mm, and the time for adding steel fiber is within 1.5 - 2.5 min.

[0028] According to an embodiment of the present disclosure, the required time for continuous stirring in step S5 is 1 - 2 min.

[0029] According to an embodiment of the present disclosure, in step S6, spraying water mist on the concrete surface for curing using a watering can means spraying water mist on the concrete surface for curing every 3 - 5 minutes. The curing time is calculated starting from the water spraying moment, and the strength can reach the expected requirements after curing for 2.5 - 3 hours.

[0030] According to another aspect of the present disclosure, there is provided a full - age - period super - crack - resistant concrete for rapid repair prepared by the method described above.

[0031] According to still another aspect of the present disclosure, there is provided an application of the full - age - period super - crack - resistant concrete for rapid repair prepared by the method described above in bridge, tunnel, highway emergency repair, airport runway / apron emergency repair projects.

[0032] The full - age - period super - crack - resistant concrete for rapid repair provided by the present disclosure, its preparation method and application have the following beneficial effects compared with the prior art:

[0033] (1) The full - age - period super - crack - resistant concrete for rapid repair provided by the present disclosure, its preparation method and application adopt technical means to accelerate the cement hydration rate, enable the plastic shrinkage of the concrete to develop completely at an extremely fast speed, and utilize the micro - expansion characteristic of sulfoaluminate cement to compensate for the later - stage hydration and drying shrinkage. At the same time, it does not significantly increase the cement dosage, does not significantly increase the cost, does not use special admixtures and shrinkage - reducing materials that affect mechanical properties, and solves the problems of rapid setting and hardening, high - strength requirements, full - age - period crack - resistance performance, full - life - cycle impermeability performance, and long - term durability of concrete materials used in rapid repair projects.

[0034] (2) The full - age - period super - crack - resistant concrete for rapid repair provided by the present disclosure, its preparation method and application do not significantly increase the cement dosage, do not significantly increase the cost, and do not use special admixtures and shrinkage - reducing materials that affect mechanical properties, realizing the preparation of full - age - period super - crack - resistant concrete for rapid repair. This has a positive significance for reducing carbon emissions and is also an important way for concrete to achieve green and low - carbon.

[0035] (3) The full - age - period super - crack - resistant concrete for rapid repair provided by the present disclosure, its preparation method and application adopt technical means to accelerate the cement hydration rate, enable the plastic shrinkage of the concrete to develop completely at an extremely fast speed, and utilize the micro - expansion characteristic of sulfoaluminate cement to compensate for the drying shrinkage of the later - stage hydration, significantly simplifying the process flow in on - site implementation. At the same time, it also eliminates the problem of insufficient long - term durability caused by using expansion agents or shrinkage - reducing agents.

[0036] (4) The all-age ultra-crack-resistant concrete for rapid repair provided by the present disclosure, its preparation method and application simplify the traditional construction process, refine the usage process of mixing water, endow the concrete with good workability and plasticity, facilitate construction and vibration, improve construction efficiency and quality, significantly reduce the time required for repair projects, and have a positive significance for quickly restoring the normal service state of the structure. Description of the Drawings

[0037] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above content and other objects, features and advantages of the present disclosure will become clearer. In the drawings:

[0038] Figure 1 The flowchart showing the method for preparing all-age ultra-crack-resistant concrete for rapid repair according to an embodiment of the present disclosure is shown.

[0039] Figure 2 The early-age shrinkage performance of the all-age ultra-crack-resistant concrete for rapid repair according to Embodiment 1 and Embodiment 2 of the present disclosure.

[0040] Figure 3 The long-age shrinkage performance of the all-age ultra-crack-resistant concrete for rapid repair according to Embodiment 1 and Embodiment 2 of the present disclosure. Specific Embodiments

[0041] 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 obscuring the concepts of the present disclosure.

[0042] The terms used herein are merely for describing specific embodiments 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.

[0043] 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 as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0044] To solve the problems faced by current concrete materials for rapid repair projects during the rapid repair process, such as rapid setting and hardening, high-strength requirements, crack resistance performance throughout the entire age period, impermeability performance throughout the entire life cycle, and long-term durability, etc., the present disclosure provides a full-age ultra-crack-resistant concrete for rapid repair, its preparation method, and applications.

[0045] As Figure 1 shown, Figure 1 the flowchart of the method for preparing full-age ultra-crack-resistant concrete for rapid repair according to an embodiment of the present disclosure is shown. The method includes the following steps:

[0046] S1: Weigh raw materials according to the following parts by weight: 400 - 430 parts of cementitious materials, 280 - 300 parts of crack-resistant admixtures, 60 - 70 parts of inert admixtures, 1450 - 1475 parts of fine aggregates, 8 - 10 parts of water reducers, 3.1 - 3.6 parts of retarders, 0.6 - 0.9 parts of defoamers, 0.08 - 0.1 parts of thickeners, 115 - 130 parts of steel fibers, 0.7 - 1 part of organic fibers, and 180 - 215 parts of water;

[0047] In this step, the cementitious material is sulfoaluminate cement. 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, and the 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 within a short time (such as within 3 h). In the present disclosure, only a small amount of sulfoaluminate cement is required to provide early strength and late micro-expansion ability, and a large amount of crack-resistant admixtures is used to achieve ultra-crack-resistant ability throughout the entire age period. This is one of the innovations.

[0048] The crack-resistant admixture is obtained by mixing silica fume, fly ash, slag powder, and calcium oxide according to a mass ratio of 1:5:6:0.35, where:

[0049] The silica fume has a silica content ≥ 95% and a specific surface area of 490 - 510 m 2 / kg. Under this condition, the silica fume has high activity and meets the requirement of accelerating the hydration reaction rate;

[0050] The fly ash is desulfurized secondary ash with a specific surface area of 300 - 390 m 2 / kg. Under this condition, the fly ash has low activity and meets the requirement of fly ash hydration in the long age period;

[0051] The slag powder is of S95 grade with a specific surface area of 380 - 430 m 2 / kg. Under this condition, the slag powder has high activity and meets the requirement of accelerating the hydration reaction rate;

[0052] The calcium oxide is industrial pure calcium oxide with a purity of ≥90%.

[0053] In the existing public and conventional mix ratios of high-strength concrete, supplementary cementitious materials such as silica fume, fly ash, and ground granulated blast-furnace slag mainly serve to reduce the cement dosage and the heat of hydration, thereby delaying the appearance of the heat of hydration peak and reducing chemical and plastic shrinkage. Calcium oxide is used as an expansive agent or shrinkage compensator. The technical route in this disclosure is completely different. The calcium oxide in the crack-resistant admixture hydrates and releases heat, increasing the hydration rate of sulfoaluminate cement. After the calcium oxide hydrates, it generates hydroxide ions to create an alkaline environment, enabling the rapid hydration of highly reactive silica fume and ground granulated blast-furnace slag. As a result, the setting and hardening time of the concrete is shortened, and thus the chemical shrinkage and plastic shrinkage of the concrete develop rapidly and significantly within a short time, allowing the shrinkage to develop completely before the concrete hardens and generates structural strength, thereby avoiding concrete cracking. This has not been mentioned in the existing technology and is one of the innovations in this disclosure.

[0054] When the concrete reaches a certain age, the dicalcium silicate in the sulfoaluminate cement begins to hydrate, providing a hydration reaction environment for fly ash together with the hydroxide ions that have not been completely consumed. The hydration of fly ash consumes water and generates shrinkage deformation. However, at the same time, the ettringite formed by the hydration of sulfoaluminate cement further grows in the alkaline environment, and the volume expansion generated compensates for the volume shrinkage and drying shrinkage caused by the hydration of fly ash. Therefore, the goal of ultra-crack resistance of long-age concrete is achieved. This has also not been mentioned in the existing technology and is one of the innovations in this disclosure.

[0055] Thus, the crack-resistant admixture obtained by mixing silica fume, fly ash, ground granulated blast-furnace slag, and calcium oxide in a specific ratio (i.e., the silica fume, fly ash, ground granulated blast-furnace slag, and calcium oxide in this disclosure are mixed in a mass ratio of 1:5:6:0.35) achieves the goal of ultra-crack resistance of concrete throughout its age.

[0056] The inert admixture mentioned above is fly ash microspheres with a specific surface area of 800 - 1050 m 2 / kg. Such admixtures hardly participate in the hydration reaction and are used to improve the fluidity of the concrete.

[0057] The fine aggregate is quartz sand, which is composed of four particle sizes of 10 - 20 mesh, 20 - 40 mesh, 40 - 70 mesh, and 70 - 140 mesh mixed in a mass ratio of 4:5:6:3. This ratio can help the concrete obtain the best fluidity.

[0058] 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.

[0059] The setting retarder used is at least one of borax, boric acid, citric acid, sodium gluconate, or tartaric acid, and is used to further extend the setting time.

[0060] The defoamer is a polyether polymer compound, which is used to eliminate large bubbles introduced into concrete due to excessive admixture of water reducer, improve the compactness of concrete, and thus improve the strength of concrete;

[0061] The thickener is a polymer compound such as methyl cellulose, hydroxypropyl methyl cellulose ether, polyacrylamide, sodium polyacrylate, polyvinyl alcohol, xanthan gum, chitosan, gelatin, modified starch, carboxymethyl cellulose ether, which is used to improve the cohesiveness of fresh concrete and facilitate construction;

[0062] The steel fiber is at least one of straight steel fiber or profiled steel fiber;

[0063] The organic fiber is at least one of polypropylene (PP) fiber, polyvinyl alcohol (PVA) fiber, alkali-resistant glass fiber, polyester fiber, with a length of 6 mm, which helps to improve the crack resistance of concrete;

[0064] The water is mixing water.

[0065] S2: Put the cementitious materials, crack-resistant admixtures, fine aggregates, coarse aggregates, water reducer, retarder, defoamer, thickener and organic fibers in the raw materials into a mixer and premix until uniform;

[0066] In this step, the mixer used is a compulsory mixer, and the premixing time required is 2 - 3 min.

[0067] S3: Add 3 / 4 of the total water consumption to the mixer and stir until uniform;

[0068] In this step, first add 1 / 2 of the total water consumption to the mixer at one time and start stirring. After 1 min, start to slowly add mixing water to the mixer continuously. The water addition time lasts for 0.5 - 1 min. In this process, a total of 1 / 2 of the remaining water consumption is added, and then stir for 1.5 - 2 min until the state is uniform. Under the process conditions of this addition of mixing water, it can prevent the segregation or bleeding phenomenon caused by excessive fluidity of concrete before adding steel fibers.

[0069] 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;

[0070] In this step, the aperture of the stainless steel square hole sieve is 8 mm - 10 mm, and the time for adding steel fibers is within 1.5 - 2.5 min. Using the square hole sieve can further simplify the steel fiber addition process and prevent the steel fibers from agglomerating.

[0071] S5: Add the remaining water to the mixer at one time, and continue to stir to obtain all-age super crack-resistant concrete for rapid repair;

[0072] In this step, the time required for continuous stirring is 1 - 2 min.

[0073] S6: Pour with the all - age - period super - crack - resistant concrete for rapid repair. After pouring, use a watering can to spray water mist on the concrete surface for curing to enhance the concrete strength to meet the expectation.

[0074] 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 - 5 minutes. The curing time is calculated from the spraying moment, and the strength can reach the expected requirement after curing for 2.5 - 3 hours.

[0075] From Figure 1 the preparation method of the all - age - period super - crack - resistant concrete for rapid repair in the illustrated embodiment, it can be known that for the method of preparing the all - age - period super - crack - resistant concrete for rapid repair in the embodiments of the present disclosure, there is no special requirement for mechanical equipment in the whole preparation process, and the total stirring time is controlled within 7.5 - 10 minutes, which is conducive to the requirement of timeliness in the emergency repair project. This technology is also one of the significant innovations of the present disclosure.

[0076] Based on Figure 1 the method of preparing the all - age - period super - crack - resistant concrete for rapid repair according to the embodiments of the present disclosure shown, the following combines Examples 1 - 2 to detail the method of preparing the all - age - period super - crack - resistant concrete for rapid repair provided by the present disclosure.

[0077] Example 1:

[0078] This example includes the following raw material components in parts by weight: 411 parts of sulfoaluminate cement, 286 parts of crack - resistant admixture, 63 parts of inert admixture, 1466 parts of fine aggregate, 209 parts of water, 8.5 parts of water - reducing agent, 3.2 parts of retarder, 0.71 part of defoamer, 0.083 part of thickener, 121 parts of steel fiber, and 0.85 part of organic fiber.

[0079] Prepare the all - age - period super - crack - resistant concrete for rapid repair by using the above raw materials according to the Figure 1 shown preparation method.

[0080] Example 2:

[0081] This example includes the following raw material components in parts by weight: 426 parts of sulfoaluminate cement, 297 parts of crack - resistant admixture, 67 parts of inert admixture, 1472 parts of fine aggregate, 188 parts of water, 9.6 parts of water - reducing agent, 3.5 parts of retarder, 0.86 part of defoamer, 0.088 part of thickener, 126 parts of steel fiber, and 0.96 part of organic fiber.

[0082] Prepare the all - age - period super - crack - resistant concrete for rapid repair by using the above raw materials according to the Figure 1 shown preparation method.

[0083] Figure 2 The early-age shrinkage performance of all-age ultra-crack-resistant concrete for rapid repair according to Embodiment 1 and Embodiment 2 of the present disclosure. Figure 2 Among them, the shrinkage rate of Embodiment 1 develops rapidly within the first 50 - 60 minutes. Although the shrinkage rate reaches about 1400 με, the concrete has not reached the initial setting state at this time (the initial setting time is 72 minutes), that is, the shrinkage at this time is plastic shrinkage, which does not affect the volume stability of the hardened concrete. Moreover, after the concrete reaches the initial setting, the shrinkage rate remains basically unchanged. The shrinkage rate of Embodiment 2 develops rapidly within the first 25 - 30 minutes, and the total shrinkage rate exceeds 1400 με. However, the concrete also has not reached the initial setting state at this time (the initial setting time is 67 minutes), that is, the shrinkage at this time is also plastic shrinkage, which does not affect the volume stability of the hardened concrete. Moreover, after the concrete reaches the initial setting, the shrinkage rate remains basically unchanged.

[0084] Figure 3 The long-term shrinkage performance of all-age ultra-crack-resistant concrete for rapid repair according to Embodiment 1 and Embodiment 2 of the present disclosure. Figure 3 Among them, after the shrinkage rate of Embodiment 1 develops to about 1400 με within the first 50 - 60 minutes, during the continuous observation for up to 70 days, the shrinkage rate basically remains unchanged, indicating that the volume stability of the hardened concrete is good. After the shrinkage rate of Embodiment 2 develops to exceed 1400 με within the first 25 - 30 minutes, during the continuous observation for up to 70 days, the shrinkage rate also basically remains unchanged, indicating that the volume stability of the hardened concrete is good.

[0085] Figure 2 and Figure 3 Fully illustrates that the concrete of Embodiment 1 and Embodiment 2 in the present disclosure can achieve the purpose of preventing shrinkage cracking through good short-term and long-term volume stability.

[0086] Table 1 Physical and mechanical properties of all-age ultra-crack-resistant concrete for rapid repair in the embodiments

[0087]

[0088] Thus, it can be seen that the preparation method of all-age ultra-crack-resistant concrete for rapid repair provided by the present disclosure adopts technical means to accelerate the cement hydration rate, so that the plastic shrinkage of the concrete develops completely at a very fast speed, and uses the micro-expansion characteristics of sulfoaluminate cement to compensate for the later hydration and drying shrinkage. At the same time, it does not significantly increase the cement dosage, does not significantly increase the cost, does not use special admixtures and shrinkage-reducing materials that affect the mechanical properties, and solves the problems of rapid setting and hardening, high-strength requirements, all-age crack resistance, full-life cycle impermeability performance, and long-term durability of concrete materials for rapid repair projects.

[0089] Furthermore, based on the above preparation method of all-age ultra-crack-resistant concrete for rapid repair, the present disclosure also provides all-age ultra-crack-resistant concrete for rapid repair prepared by the described method. This all-age ultra-crack-resistant concrete for rapid repair uses technical means to accelerate the hydration rate of cement, enabling the plastic shrinkage of the concrete to develop and complete at an extremely fast speed. The micro-expansion characteristics of sulfoaluminate cement are utilized to compensate for the drying shrinkage during later hydration, significantly simplifying the process flow in on-site implementation. At the same time, it also eliminates the problem of insufficient long-term durability caused by the use of expansive agents or shrinkage-reducing agents. Without significantly increasing the cement dosage, without significantly increasing the cost, and without using special admixtures and shrinkage-reducing materials that affect mechanical properties, the preparation of all-age ultra-crack-resistant concrete for rapid repair is achieved, which is of positive significance for reducing carbon emissions and is also an important way for concrete to achieve green and low-carbon development.

[0090] Furthermore, based on the above all-age ultra-crack-resistant concrete for rapid repair and its preparation method, the present disclosure also provides an application of all-age ultra-crack-resistant concrete for rapid repair prepared by the described method in bridge, tunnel, highway emergency repair, airport runway / apron emergency repair projects.

[0091] 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.

[0092] The above describes the embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes and not for limiting the scope of the present disclosure. Although the various embodiments are 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 all-age ultra-crack-resistant concrete for rapid repair, characterized in that Including: S1: Weigh the raw materials according to the following parts by weight: 400 - 430 parts of cementitious material, 280 - 300 parts of crack - resistant admixture, 60 - 70 parts of inert admixture, 1450 - 1475 parts of fine aggregate, 8 - 10 parts of water - reducing agent, 3.1 - 3.6 parts of retarder, 0.6 - 0.9 parts of defoamer, 0.08 - 0.1 parts of thickener, 115 - 130 parts of steel fiber, 0.7 - 1 part of organic fiber, and 180 - 215 parts of water; S2: Put the cementitious material, crack - resistant admixture, fine aggregate, coarse aggregate, water - reducing agent, retarder, defoamer, thickener and organic fiber in the raw materials into a mixer and premix until uniform; S3: Add 3 / 4 of the total water consumption to the mixer 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 all - age - period super - crack - resistant concrete for rapid repair; S6: Use the all - age - period super - crack - resistant concrete for rapid repair for pouring. After pouring, use a watering can to spray water mist on the concrete surface for curing to enhance the concrete strength to reach the expected level.

2. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, The cementitious material described in step S1 is sulfoaluminate cement. 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 all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, The crack - resistant admixture described in step S1 is obtained by mixing silica fume, fly ash, slag powder and calcium oxide in a mass ratio of 1:5:6:0.35, where: The silica content of silica fume is ≥95%, and the specific surface area is 490 - 510 m 2 / kg; The fly ash is the secondary ash for desulfurization, with a specific surface area of 300 - 390 m 2 / kg; The slag powder is of S95 grade with a specific surface area of 380 - 430 m 2 / kg; The calcium oxide is industrial pure calcium oxide with a purity ≥ 90%.

4. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that The inert admixture described in step S1 is fly ash microspheres, with a specific surface area of 800 - 1050 m 2 / kg.

5. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, The fine aggregate described in step S1 is quartz sand, which is composed of four particle sizes of 10 - 20 mesh, 20 - 40 mesh, 40 - 70 mesh and 70 - 140 mesh mixed in a mass ratio of 4:5:6:

3.

6. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, The water - reducing agent described in step S1 is at least one of polycarboxylate superplasticizer, naphthalene - based water - reducing agent, anthracene - based water - reducing agent, and lignosulfonate water - reducing agent.

7. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, The retarder described in step S1 is at least one of borax, boric acid, citric acid, sodium gluconate or tartaric acid.

8. The preparation method of all - age - period super - crack - resistant concrete for rapid repair according to claim 1, characterized in that The defoamer described in step S1 is a polyether - type polymer compound; The thickener described in step S1 is a polymer compound such as methyl cellulose, hydroxypropyl methyl cellulose ether, polyacrylamide, sodium polyacrylate, polyvinyl alcohol, xanthan gum, chitosan, gelatin, modified starch, carboxymethyl cellulose ether; The steel fiber described in step S1 is at least one of straight - type or profiled steel fiber; The organic fiber described in step S1 is at least one of polypropylene (PP) fiber, polyvinyl alcohol (PVA) fiber, alkali - resistant glass fiber, polyester fiber; The water described in step S1 is mixing water.

9. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that The mixer described in step S2 is a compulsory mixer, and the premixing time required is 2 - 3 min.

10. The preparation method of the all-age anti-cracking concrete for rapid repair according to claim 1, characterized in that The adding 3 / 4 of the total water consumption to the mixer and stirring until uniform described in step S3 includes: Add 1 / 2 of the total water consumption to the mixer at one time and start mixing. After 1 minute, continue to slowly add mixing water to the mixer. 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 mix for 1.5 - 2 minutes until the state is uniform.

11. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair 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 fibers is within 1.5 - 2.5 minutes.

12. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, wherein The time required for continuous mixing described in step S5 is 1 - 2 minutes.

13. The preparation method of the all-age ultra-crack-resistant concrete for rapid repair according to claim 1, characterized in that, In step S6, spraying water mist on the concrete surface with a watering can for curing means spraying water mist on the concrete surface with a watering can every 3 - 5 minutes. The curing time is calculated starting from the spraying moment. After curing for 2.5 - 3 hours, the strength can reach the expected requirements.

14. A full-age ultra-crack-resistant concrete for rapid repair prepared by the method according to any one of claims 1 to 13.

15. Application of a full-age ultra-crack-resistant concrete for rapid repair prepared by the method according to any one of claims 1 to 13 in bridge, tunnel, highway emergency repair, airport runway / apron emergency repair projects.

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