Wear-resistant and impact-resistant cement-based gradient material as well as preparation method and application thereof

Abstract

The invention provides a wear-resistant and impact-resistant cement-based gradient material as well as a preparation method and application thereof, and relates to the technical field of building materials. The wear-resistant and impact-resistant cement-based gradient material comprises a base layer material and a surface layer material which exist independently, both the base layer material and the surface layer material are ultra-high performance concrete, the sand-cement ratio of the base layer material is 0.4-1.2, and the sand-cement ratio of the surface layer material is 1.0-3.0. Through gradient design of the base layer material and the surface layer material with different sand-cement ratios, the wear resistance of the material is optimized, and the tensile property and the impact resistance of the material are improved, so that the overall mechanical property of the ultra-high-performance cement-based material is improved, the mechanical property requirement of special engineering is met, and the application prospect is wide. The method can be widely applied to preparation of military shelters, nuclear power station shells, mine shafts, road anti-collision walls and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a wear-resistant and impact-resistant cement-based gradient material and a preparation method and application thereof. BACKGROUND

[0002] Ultra high performance cement-based materials, especially ultra high performance concrete (UHPC), are characterized by ultra high strength, toughness and durability, and become a new system to realize the performance leap of cement-based materials. Compared with ordinary concrete, UHPC can greatly reduce the material consumption, reduce the construction cost, save resources, and reduce the energy consumption of production, transportation and construction. The use of UHPC will contribute to environmental protection. Although the strength and toughness of UHPC are already very high, in some special projects such as military shelters, nuclear power plant shells, mine shafts, highway crash walls, etc., not only quasi-static load is borne, but also high-strength dynamic impact is borne, so a certain impact resistance is also required. At present, fibers are further added to UHPC materials to enhance the toughness of concrete, which has a certain effect on improving the impact resistance of UHPC, but the overall improvement effect is not significant.

[0003] The prior art CN117756468A discloses an impact-resistant and wear-resistant ultra high performance concrete and a construction method thereof, wherein the concrete comprises the following components in parts by weight: modified ultra-fine cement 100-150 parts, wear-resistant aggregate 180-210 parts, water 40-60 parts, fly ash 15-20 parts, S95 slag powder 30-40 parts, alumina fine powder with a particle size of ≤0.074 mm 15-20 parts, water reducing agent 4-5 parts, and reinforcing fiber 1-5 parts; wherein the modified cement is prepared by adding S95 slag powder, fly ash, grinding aid and rheological modifier to the cement for grinding to prepare modified ultra-fine cement with a specific surface of 800-1000 m 2 / kg; the weight ratio of the cement, S95 slag powder, fly ash, grinding aid and rheological modifier is 52-60:20-30:10-15:2-6:1-3. Although the strength of the impact-resistant and wear-resistant ultra high performance concrete is improved to a certain extent, the structure of the material after adding the fiber is not changed, so the improvement effect on the performance is limited, and the wear-resistant and impact-resistant performance still needs to be further improved from the structure of the fiber-added material. SUMMARY

[0004] The application provides a cement-based gradient material and a preparation method and application thereof, and mainly aims to solve the problem of poor impact resistance of current ultra-high performance concrete, realizes ultra-high compressive strength of the material through closest packing of the material, optimizes the wear resistance of the material through the proportion of cementitious material and aggregate, improves the tensile and impact resistance of the material through design of the gradient functional material, changes the combined state from the overall structure of the material, and thus improves the overall mechanical properties of the ultra-high performance cement-based material and meets the mechanical property requirements of special projects.

[0005] The application provides a wear-resistant and impact-resistant cement-based gradient material, which comprises independently existing base layer material and surface layer material. The sand-binder ratio of the base layer material is 0.4-1.2, and the fiber content is 25-150 kg per cubic meter of ultra-high performance concrete. The sand-binder ratio of the surface layer material is 1.0-3.0, and the fiber content is 100-300 kg per cubic meter of ultra-high performance concrete.

[0006] According to the application, the fiber in the base layer material is preferably one or more of steel fiber, polyformaldehyde fiber, basalt fiber, polypropylene fiber and polyvinyl alcohol fiber.

[0007] According to the application, the fiber in the base layer material has a diameter of 0.2-1 mm and a length of 8-20 mm.

[0008] According to the application, the fiber in the surface layer material is preferably one or more of steel fiber, polyformaldehyde fiber, polypropylene fiber, basalt fiber and polyvinyl alcohol fiber.

[0009] According to the application, the fiber in the surface layer material has a diameter of 0.2-1 mm and a length of 8-40 mm.

[0010] According to the application, the ultra-high performance concrete comprises the following components in parts by weight: The cementitious material is 660-2100 parts, the aggregate is 1000-1600 parts, the fiber is 25-200 parts, the water is 150-210 parts, the water reducing agent is 15-35 parts, and the defoaming agent is 0.01-0.2 parts.

[0011] According to the application, the wear-resistant and impact-resistant cement-based gradient material further comprises independently existing intermediate layer fiber mesh material, and the intermediate layer is arranged between the base layer and the surface layer in use.

[0012] The abrasion-resistant and impact-resistant cement-based gradient material provided by the present application, preferably, the fiber mesh grid diameter of the intermediate layer fiber mesh material is not more than 3 times the fiber diameter in the base layer material and the surface layer material, and the fiber mesh grid length is not less than 3 times the fiber length in the base layer material and the surface layer material.

[0013] The abrasion-resistant and impact-resistant cement-based gradient material provided by the present application, preferably, the fiber mesh grid diameter is 0.2-1 mm, and the fiber mesh grid length is 25-60 mm.

[0014] The abrasion-resistant and impact-resistant cement-based gradient material provided by the present application, preferably, the intermediate layer fiber mesh material is any one of a steel fiber mesh, a carbon fiber mesh or a glass fiber mesh.

[0015] The present application also provides a functional gradient concrete composite material comprising a base layer and a surface layer, which are prepared from the abrasion-resistant and impact-resistant cement-based gradient material provided by the present application, wherein the base layer is prepared by pouring the base layer material, the surface layer is prepared by pouring the surface layer material, and when the fluidity of the base material and the surface layer material is greater than 700 and / or vertical construction is performed, the intermediate layer fiber mesh material is added between the base layer and the surface layer.

[0016] The present application also provides a preparation method of a functional gradient concrete composite material, comprising the following steps: S1. mixing cementitious materials, aggregates and fibers in the base layer material in a mass ratio to obtain a mixture, mixing water, a water reducing agent, a defoaming agent and the mixture in the base layer material in a mass ratio to obtain a fresh concrete slurry, and mixing the fibers in the base layer material to obtain a base layer fresh ultra-high performance concrete slurry; S2. mixing cementitious materials, aggregates and fibers in the surface layer material in a mass ratio to obtain a mixture, mixing water, a water reducing agent, a defoaming agent and the mixture in the surface layer material in a mass ratio to obtain a fresh concrete slurry, and mixing the fibers in the surface layer material to obtain a surface layer fresh ultra-high performance concrete slurry; S3. pouring the base layer material first, and then pouring the surface layer material, when the fluidity of the two layers of materials is greater than 700, adding the intermediate layer fiber mesh material before pouring the surface layer material to separate the base layer and the surface layer, and / or when vertical pouring is performed, adding the intermediate layer fiber mesh material before pouring to separate the base layer and the surface layer, and then pouring the base layer material and the surface layer material at the same time to prepare the functional gradient concrete composite material.

[0017] The present application also provides an application of the functional gradient concrete composite material or the functional gradient concrete composite material prepared by the preparation method of the present application in the preparation of military shelters, nuclear power plant shells, mine shafts and highway crash barriers.

[0018] Beneficial effects: The wear-resistant impact-resistant cement-based gradient material provided by the application optimizes the wear resistance of the material through gradient design of the base layer material and the surface layer material with different sand-binder ratios, improves the tensile and impact resistance of the material, thereby improving the overall mechanical properties of the ultra-high performance cement-based material, and the 72h impact and wear resistance can reach 183h / kgm -2 , meets the mechanical property requirements of special projects, and can be widely used in the preparation of military shelters, nuclear power plant shells, mine shafts, highway crash walls and the like. DETAILED DESCRIPTION

[0019] The following examples are used to illustrate the application, but are not used to limit the scope of the application. If the specific technology or condition is not specified in the examples, it is carried out according to the technology or condition described in the literature in the art, or according to the product manual. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be purchased through a regular channel.

[0020] In a specific embodiment, the application provides a wear-resistant impact-resistant cement-based gradient material, which comprises independently existing base layer material and surface layer material, the base layer material and the surface layer material are both ultra-high performance concrete, wherein the sand-binder ratio of the base layer material is 0.4-1.2, and the fiber dosage is 25-150 kg per cubic meter of ultra-high performance concrete, the sand-binder ratio of the surface layer material is 1.0-3.0, and the fiber dosage is 100-300 kg per cubic meter of ultra-high performance concrete.

[0021] It should be noted that: The sand-binder ratio mentioned in the application is the ratio of aggregate to cementitious material.

[0022] The fiber dosage is the reference dosage per cubic meter of ultra-high performance concrete.

[0023] The base layer material and the surface layer material in the wear-resistant impact-resistant cement-based gradient material of the application are independently packaged before use. In specific use, the base layer material is mixed and poured on the base layer, and then the surface layer material is mixed and poured on the surface of the base layer. In the process of pouring and forming, the two layers with different sand-binder ratios will diffuse and penetrate, and the components between the two layers will form a gradient distribution.

[0024] In a specific embodiment, the sand-binder ratio of the base layer material may be, for example, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, etc. point value or range value composed of any, and the fiber dosage per cubic meter of ultra-high performance concrete may be 25 kg, 50 kg, 75 kg, 100 kg, 125 kg, 150 kg, etc. point value or range value composed of any.

[0025] In the specific embodiments, the sand mortar ratio of the surface layer material can be 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, etc. or any range value formed by the point values, and the fiber dosage per cubic meter of ultra-high performance concrete can be 100 kg, 125 kg, 150 kg, 175 kg, 200 kg, 225 kg, 250 kg, 275 kg, 300 kg, etc. or any range value formed by the point values.

[0026] In the wear-resistant and impact-resistant cement-based gradient material of the present application, by designing the base layer material and the surface layer material with different sand mortar ratios, i.e. by adjusting the ratio of cementitious material to aggregate in each layer of material and controlling the fiber dosage, the base layer material can exhibit better flowability and increase the bonding strength with the base; the surface layer material exhibits better wear resistance, tensile resistance and impact resistance, thereby improving the overall performance of the ultra-high performance cement-based material and meeting the performance requirements of special projects.

[0027] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present application, in some specific embodiments, the fibers in the base layer material of the present application can be common fibers in the field, such as preferably one or more of steel fibers, polyformaldehyde fibers, polypropylene fibers and polyvinyl alcohol fibers.

[0028] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present application, in some specific embodiments, the fibers in the surface layer material of the present application can be common fibers in the field, such as preferably one or more of steel fibers, polyformaldehyde fibers, polypropylene fibers and polyvinyl alcohol fibers.

[0029] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present application, in some specific embodiments, the fibers in the base layer material and the fibers in the surface layer material can be the same or different.

[0030] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present application, in order to make the base layer material have better flowability, in some specific embodiments, the fibers in the base layer material of the present application have a diameter of 0.2 mm to 1 mm and a length of 8 to 20 mm, such as 8 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, etc. or any range value formed by the point values.

[0031] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present application, in order to make the material surface have better wear resistance and impact resistance, in some specific embodiments, the fibers in the surface layer material of the present application have a diameter of 0.2 mm to 1 mm and a length of 8 to 40 mm, such as 8 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, etc. or any range value formed by the point values.

[0032] According to the present application, a wear-resistant and impact-resistant cement-based gradient material is provided, as above, in some embodiments, wherein the length of the fibers in the base layer material and the length of the fibers in the surface layer material can be the same or different.

[0033] According to the present application, a wear-resistant and impact-resistant cement-based gradient material is provided, as above, in some embodiments, wherein the length of the fibers in the base layer material and the length of the fibers in the surface layer material can be the same or different. The cementitious material 660~2100 parts, the aggregate 1000~1600 parts, the fiber 25~200 parts, the water 150~210 parts, the water reducing agent 15~35 parts, and the defoaming agent 0.01~0.2 parts.

[0034] In embodiments, the cementitious material mentioned in the present application can include cement, silica fume, fly ash, mineral powder, etc., and more specifically, the cementitious material includes the following components in parts by weight: Cement 600~1500 parts, silica fume 60~200 parts, fly ash 0~250 parts, and mineral powder 0~150 parts.

[0035] In embodiments, the cement mentioned in the present application can be Portland cement, and in order to further improve the strength of the ultra-high performance concrete, the cement can be P.O 42.5 cement or P.O 52.5 cement.

[0036] The quartz sand mentioned in the present application is the aggregate of the concrete material, and in embodiments, can be composed of quartz sand of different particle sizes, for example, one or more of 4~7 mesh quartz sand, 7~10 mesh quartz sand, 10~20 mesh quartz sand, 20~40 mesh quartz sand, and 40~90 mesh quartz sand, and preferably a mixture of 4~7 mesh quartz sand, 7~10 mesh quartz sand, 10~20 mesh quartz sand, 20~40 mesh quartz sand, and 40~90 mesh quartz sand, wherein the mass ratio of 4~7 mesh quartz sand, 7~10 mesh quartz sand, 10~20 mesh quartz sand, 20~40 mesh quartz sand, and 40~90 mesh quartz sand is (20~25):(10~15)(20~25):(25~30):(10~15).

[0037] According to the present application, a wear-resistant and impact-resistant cement-based gradient material is provided, as above, in some embodiments, wherein the length of the fibers in the base layer material and the length of the fibers in the surface layer material can be the same or different. JZ: cement 750 parts, silica fume 150 parts, fly ash 100 parts, mineral powder 50 parts, aggregate 1010 parts, water 180 parts, water reducing agent 28 parts, defoaming agent 0.1 parts, and fiber 150 parts.

[0038] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in some embodiments, the ultra-high performance concrete of the present application comprises, for example, the following components by weight: JC-08: cement 900 parts, silica fume 130 parts, fly ash 150 parts, mineral powder 100 parts, aggregate 1030 parts, water 210 parts, water reducing agent 25 parts, defoaming agent 0.1 part, fiber 80 parts.

[0039] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in some embodiments, the ultra-high performance concrete of the present application comprises, for example, the following components by weight: JC-14: cement 750 parts, silica fume 80 parts, fly ash 120 parts, mineral powder 0 parts, aggregate 1300 parts, water 165 parts, water reducing agent 30 parts, defoaming agent 0.1 part, fiber 200 parts.

[0040] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in some embodiments, the ultra-high performance concrete of the present application comprises, for example, the following components by weight: JC-02: cement 1400 parts, silica fume 100 parts, fly ash 250 parts, mineral powder 150 parts, aggregate 350 parts, water 260 parts, water reducing agent 15 parts, defoaming agent 0.1 part, fiber 25 parts.

[0041] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in some embodiments, the ultra-high performance concrete of the present application comprises, for example, the following components by weight: JC-30: cement 470 parts, silica fume 60 parts, fly ash 50 parts, mineral powder 0 parts, aggregate 1750 parts, water 120 parts, water reducing agent 35 parts, defoaming agent 0.1 part, fiber 200 parts.

[0042] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in some embodiments, in order to further strengthen the wear-resistant and impact-resistant performance and strength of the functionally gradient concrete composite material constructed by the cement-based gradient material, an independently existing intermediate layer fiber mesh material is preferably further included, the intermediate layer is arranged between the base layer and the surface layer when in use.

[0043] A wear-resistant and impact-resistant cement-based gradient material is provided according to the present application, in order to ensure that the mesh does not introduce holes and cracks, and at the same time better form the gradient change between the base layer and the surface layer material, in some embodiments, the fiber mesh grid diameter of the intermediate layer fiber mesh material is not more than 3 times the fiber diameter in the base layer material and the surface layer material, and the fiber mesh grid length is not less than 3 times the fiber length in the base layer material and the surface layer material.

[0044] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present invention, in certain specific embodiments, the fiber mesh grid diameter is 0.2-1.0 mm, and the fiber mesh grid length is 25-60 mm.

[0045] For example, the mesh diameter of the fiber mesh can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or any range thereof.

[0046] For example, the fiber mesh length can be 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, or any range thereof.

[0047] According to the wear-resistant and impact-resistant cement-based gradient material provided by the present invention, in certain specific embodiments, the fiber mesh material of the middle layer is any one of a steel fiber mesh, a carbon fiber mesh or a glass fiber mesh.

[0048] According to a wear-resistant and impact-resistant cement-based gradient material provided by the present invention, in some specific embodiments, the base layer material of the present invention can be JC-08, the surface layer material is JC-14, and the fiber mesh mesh diameter of the intermediate layer fiber mesh material is 0.5 mm and the fiber mesh mesh length is 30 mm.

[0049] According to a wear-resistant and impact-resistant cement-based gradient material provided by the present invention, in some specific embodiments, the base layer material of the present invention can be JC-02, the surface layer material is JC-14, and the fiber mesh mesh diameter of the intermediate layer fiber mesh material is 0.5 mm and the fiber mesh mesh length is 30 mm.

[0050] According to a wear-resistant and impact-resistant cement-based gradient material provided by the present invention, in some specific embodiments, the base layer material of the present invention can be JC-08, the surface layer material is JC-30, and the fiber mesh mesh diameter of the intermediate layer fiber mesh material is 0.5 mm and the fiber mesh mesh length is 30 mm.

[0051] On the other hand, in some specific embodiments, the present invention also provides a functional gradient concrete composite material, including a base layer and a surface layer, which is prepared from the wear-resistant and impact-resistant cement-based gradient material provided by the present invention, wherein the base layer is cast by the base layer material, and the surface layer is cast by the surface layer material.

[0052] In some specific embodiments, when the fluidity of the base layer and the surface layer material is greater than 700, an intermediate layer of fiber web material is added between the base layer and the surface layer.

[0053] In some embodiments, when the base layer and the surface layer of the functional gradient concrete composite material are cast by vertical construction, the application also preferably adds an intermediate layer of fiber mesh material between the base layer and the surface layer.

[0054] In the above two cases, the addition of an intermediate layer of fiber mesh material between the base layer and the surface layer can prevent the two materials from mixing completely, thereby ensuring the formation of a gradient material with gradually changing composition between the base layer and the surface layer materials.

[0055] On the other hand, the formulation system of the application also needs to be matched with the corresponding stirring and molding system. In some embodiments, the application also provides a method for preparing a functional gradient concrete composite material, comprising the following steps: S1. mixing the cementitious material, aggregate and fiber in the base layer material in a mass ratio to obtain a mixture, then mixing the water, water reducing agent, defoaming agent and mixture in the base layer material in a mass ratio to obtain a fresh concrete slurry, and then mixing the fiber in the base layer material to obtain a fresh base layer ultra-high performance concrete slurry; S2. mixing the cementitious material, aggregate and fiber in the surface layer material in a mass ratio to obtain a mixture, then mixing the water, water reducing agent, defoaming agent and mixture in the surface layer material in a mass ratio to obtain a fresh concrete slurry, and then mixing the fiber in the surface layer material to obtain a fresh surface layer ultra-high performance concrete slurry; S3. first casting the base layer material, then casting the surface layer material, when the fluidity of the two layers is greater than 700, adding an intermediate layer of fiber mesh material before casting the surface layer material to separate the base layer and the surface layer, and / or when vertically casting, adding an intermediate layer of fiber mesh material before casting to separate the base layer and the surface layer, then simultaneously casting the base layer material and the surface layer material to obtain a functional gradient concrete composite material.

[0056] In the S3 step of the application, the casting of the base layer and the surface layer can be performed in the following two ways: For horizontal casting, first cast the base layer material, then cast the surface layer material, if the fluidity of the base layer material and / or the surface layer material is greater than 700, then preferably add an intermediate layer of fiber mesh material before casting the surface layer material after casting the base layer material to separate the base layer and the surface layer, and then cast the surface layer material to obtain a functional gradient concrete composite material.

[0057] For vertical casting, cast the base layer material on the inside and the surface layer material on the outside, and before casting, add a steel mesh to separate the casting cavity into a base layer and a surface layer, then simultaneously cast the inside base layer material and the outside surface layer material to obtain a functional gradient concrete composite material.

[0058] For any of the above pouring methods, the mesh diameter of the intermediate layer fiber mesh material is preferably less than 3 times the longest length of the fiber diameter in the base layer material and the surface layer material.

[0059] In still another aspect, in some embodiments, the present application also provides the use of the functionally graded concrete composite material or the functionally graded concrete composite material prepared according to the preparation method of the present application in the preparation of military shelters, nuclear power plant shells, mine shafts, and highway crash barriers. Example 1 A wear-resistant and impact-resistant cement-based gradient material FGCC-1, comprising independently existing base layer material, surface layer material and intermediate layer fiber mesh material, the intermediate layer being arranged between the base layer and the surface layer in use, the base layer material and the surface layer material are both ultra-high performance concrete, the FGCC-1 has a base layer of JC-08, a surface layer of JC-14, the fiber mesh material of the intermediate layer has a fiber mesh diameter of 0.5 mm and a fiber mesh length of 30 mm, and the intermediate layer fiber mesh material is a steel fiber mesh.

[0060] The specific base layer material and surface layer material ultra-high performance concrete ratio is shown in Table 1 below.

[0061] Wherein the fiber is a steel fiber, the fiber diameter is 0.2 mm, the fiber length is 13 mm, and the fiber dosage is 0.2 kg per cubic meter of ultra-high performance concrete.

[0062] JZ is a common UHPC material.

[0063] When the wear-resistant and impact-resistant cement-based gradient material contains the intermediate layer fiber mesh material, if the fiber mesh diameter of the intermediate layer fiber mesh material is not properly selected, for example, exceeds 3 times the fiber diameter in the base layer material and the surface layer material, the performance will be significantly degraded, and the performance effect of the wear-resistant and impact-resistant cement-based gradient material in the embodiments of the present application cannot be achieved.

[0064] Example 2 A wear-resistant and impact-resistant cement-based gradient material FGCC-2, comprising independently existing base layer material, surface layer material and intermediate layer fiber mesh material, the intermediate layer being arranged between the base layer and the surface layer in use, the base layer material and the surface layer material are both ultra-high performance concrete, the FGCC-1 has a base layer of JC-02, a surface layer of JC-14, the fiber mesh material of the intermediate layer has a fiber mesh diameter of 0.5 mm and a fiber mesh length of 30 mm, and the intermediate layer fiber mesh material is a steel fiber mesh.

[0065] Example 3 A wear-resistant and impact-resistant cement-based gradient material FGCC-2, comprising independently existing base layer material, surface layer material and intermediate layer fiber mesh material, the intermediate layer being arranged between the base layer and the surface layer in use, the base layer material and the surface layer material are both ultra-high performance concrete, the FGCC-1 is that the base layer is JC-08, the surface layer is JC-30, the fiber mesh grid diameter of the intermediate layer fiber mesh material is 0.5 mm, the fiber mesh grid length is 30 mm, and the intermediate layer fiber mesh grid material is a steel fiber mesh grid.

[0066] Example 4 A functional gradient concrete composite material comprising a base layer and a surface layer, prepared from the wear-resistant and impact-resistant cement-based gradient material of examples 1~4, wherein the base layer is cast from the base layer material and the surface layer is cast from the surface layer material.

[0067] The preparation method of the above functional gradient concrete composite material comprises the following steps: S1. The cementitious materials, quartz sand and silica fume in the base layer material are mixed in a mass ratio to obtain a mixture, then the water, water reducing agent, defoaming agent and the mixture in the base layer material are mixed in a mass ratio to obtain a fresh concrete slurry, and then the fibers in the base layer material are mixed to obtain a fresh base layer ultra-high performance concrete slurry; S2. The cementitious materials, quartz sand and silica fume in the surface layer material are mixed in a mass ratio to obtain a mixture, then the water, water reducing agent, defoaming agent and the mixture in the surface layer material are mixed in a mass ratio to obtain a fresh concrete slurry, and then the fibers in the surface layer material are mixed to obtain a fresh surface layer ultra-high performance concrete slurry; S3. For horizontal casting projects, the base layer material is cast first, and then the surface layer material is cast; for vertical projects, the base layer material is cast on the inside and the surface layer material is cast on the outside, both materials are cast at the same time, and if the flow degree of both materials is greater than 700, a steel mesh is added to divide the casting cavity before casting.

[0068] Comparative examples 1~4 A concrete composite material, the base layer and the surface layer are cast using the same ultra-high performance concrete.

[0069] The ultra-high performance concrete in comparative examples 1~4 is JZ, JC-08, JC-14, JC-02 and JC-30, respectively.

[0070] Result detection The flowability, 28-day compressive and impact strength of the ultra-high performance concrete in the test examples and comparative examples, and the related performance of the functional gradient concrete composite material are detected.

[0071] The expansion degree is detected according to GB50080-2016.

[0072] 28d tensile strength and 28d compressive strength are detected according to GB50081-2019.

[0073] Impact energy dissipation and impact abrasion resistance are detected according to GB / T 7019-2024 and DL / T 5150--2017 (water washing steel ball method).

[0074] The detection results are shown in Table 2.

[0075] Table 2

[0076] As shown in Table 2, after the gradient material is formed in Examples 1-3 of the present application, the impact abrasion resistance of the surface layer material is effectively preserved, the impact energy dissipation of the material is significantly increased, and the material has better impact abrasion resistance. Comparative Examples 1-4 use the same base layer slurry and surface layer slurry without gradient design, and not only the 28-day tensile strength and 28-day compressive strength are significantly inferior to the present application, but also the relevant impact abrasion resistance detection indicators are significantly inferior to the present application.

[0077] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A wear-resistant and impact-resistant cement-based gradient material, characterized in that: It includes independent base layer materials and surface layer materials, both of which are ultra-high performance concrete. The sand-to-cement ratio of the base layer material is 0.4-1.2, and the fiber dosage is 25-150 kg per cubic meter of ultra-high performance concrete. The sand-to-cement ratio of the surface layer material is 1.0-3.0, and the fiber dosage is 100-300 kg per cubic meter of ultra-high performance concrete.

2. The wear-resistant and impact-resistant cement-based gradient material according to claim 1, characterized in that: The base layer material and the surface layer material meet at least one of the following conditions: (1) The fibers in the base layer material are one or more of steel fibers, polyoxymethylene fibers, basalt fibers, polypropylene fibers, and polyvinyl alcohol fibers; (2) The fibers in the surface layer material are one or more of steel fibers, polyoxymethylene fibers, basalt fibers, polypropylene fibers, and polyvinyl alcohol fibers.

3. The wear-resistant and impact-resistant cement-based gradient material according to claim 1, characterized in that: The fiber diameter of the base layer material is 0.2-1 mm and the length is 8-20 mm, and / or the fiber diameter of the surface layer material is 0.2-1 mm and the length is 8-40 mm.

4. The wear-resistant and impact-resistant cement-based gradient material according to any one of claims 1 to 3, characterized in that: The ultra-high performance concrete comprises the following components in parts by weight: 660~2100 parts of cementitious material, 1000~1600 parts of aggregate, 25~200 parts of fiber, 150~210 parts of water, 15~35 parts of water reducer, and 0.01~0.2 parts of defoaming agent.

5. The wear-resistant and impact-resistant cement-based gradient material according to any one of claims 1 to 3, characterized in that: It also includes an independent middle layer fiber mesh material, which is arranged between the base layer and the surface layer when in use. The fiber mesh grid diameter of the middle layer fiber mesh material is not greater than 3 times the fiber diameter in the base layer material and the surface layer material, and the fiber mesh grid length is not less than 3 times the fiber length in the base layer material and the surface layer material.

6. The wear-resistant and impact-resistant cement-based gradient material according to claim 5, characterized in that: The fiber mesh diameter of the intermediate layer fiber mesh material is 0.2-1 mm, and the fiber mesh length is 25-60 mm.

7. The wear-resistant and impact-resistant cement-based gradient material according to claim 6, characterized in that: The fiber mesh material of the middle layer is any one of steel fiber mesh, carbon fiber mesh or glass fiber mesh.

8. A functionally graded concrete composite material comprising a base layer and a surface layer, characterized in that: It is prepared from the wear-resistant and impact-resistant cement-based gradient material according to any one of claims 1 to 7, wherein the base layer is cast by the base layer material, and the surface layer is cast by the surface layer material. When the fluidity of the base material and the surface layer material is greater than 700, and / or when vertical construction is carried out, an intermediate layer of fiber mesh material is added between the base layer and the surface layer.

9. A method for preparing the functionally gradient concrete composite material according to claim 8, characterized in that: The steps include: S1. The cementitious material, aggregate, and fiber in the base layer material are mixed in a mass ratio to obtain a mixture, and then the water, water reducer, defoamer, and mixture in the base layer material are mixed in a mass ratio to obtain a fresh concrete slurry, which is then mixed with the fiber in the base layer material to obtain a fresh ultra-high performance concrete slurry for the base layer; S2. The cementitious material, aggregate and fiber in the surface layer material are mixed in a mass ratio to obtain a mixture, and then the water, water reducer, defoamer and mixture in the surface layer material are mixed in a mass ratio to obtain a fresh concrete slurry, which is then mixed with the fiber in the surface layer material to obtain a fresh ultra-high performance concrete slurry for the surface layer; S3. First cast the base layer material, and then cast the surface layer material. When the fluidity of the two layers of materials is greater than 700, add an intermediate layer of fiber mesh material before casting the surface layer material to separate the base layer and the surface layer, and / or during vertical casting, add an intermediate layer of fiber mesh material before casting to separate the base layer and the surface layer, and then cast the base layer material and the surface layer material at the same time to prepare a functional gradient concrete composite material.

10. Use of the functionally gradient concrete composite material according to claim 8 in the preparation of military bunkers, nuclear power plant shells, mine shafts, and highway crash barriers.

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