A phase transformation tough concrete material, its preparation method and application

Abstract

This invention provides a phase change toughness concrete material and its preparation method, as well as its applications. The raw materials for the concrete material of this invention include at least cement, composite ash, crushed stone, sand, water-reducing agent, and composite fiber; based on 100 parts by weight of cement, the raw materials include: 100 parts by weight of cement, 30-42 parts by weight of composite ash, 230-300 parts by weight of crushed stone, 120-150 parts by weight of sand, 1-1.2 parts by weight of water-reducing agent, and 2-5 parts by weight of phase change material. The concrete material prepared by this invention can be used in various building structures, possessing both thermal insulation and toughness and strength.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a phase transformation toughness concrete material, its preparation method, and its application. Background Technology

[0002] Phase change materials (PCMs) are increasingly used in building walls due to their constant phase change temperature, good energy storage effect, and good stability. However, the application of PCMs in building materials still has drawbacks. For example, as the amount of PCM added increases, the strength of the composite material decreases significantly; the high porosity of the composite material leads to a low phase change rate. In the field of materials science, the structural strength of PCM concrete is a crucial design consideration, and the addition of PCM particles makes the material brittle and reduces its strength.

[0003] Currently, to address the decline in strength, stiffness, and crack resistance of phase change concrete (PCC), the common approach is to incorporate appropriate amounts of fibers and additives (such as reinforcing agents) into the concrete matrix to enhance the strength and toughness of the composite material. However, the bond between PCC and the concrete matrix is ​​weak, and the aggregate encapsulating the PCC itself has low strength, making it prone to leakage. This can negatively impact energy storage and insulation performance. Leakage of inorganic PCCs can even increase the porosity of the concrete, further exacerbating the problem. Adding appropriate amounts of fibers and additives to the concrete matrix cannot adequately compensate for the adverse effects of PCCs. Summary of the Invention

[0004] This invention provides a phase transformation toughness concrete material and its preparation method. The concrete material prepared by this invention can be used in various building structures, and has both thermal insulation and toughness and strength.

[0005] The technical solution of this invention is as follows:

[0006] A concrete material, wherein the raw materials of the concrete material include at least cement, composite ash, crushed stone, sand, water-reducing agent, and composite fiber.

[0007] According to an embodiment of the present invention, the raw materials comprise, per 100 parts by weight of cement:

[0008] 100 parts by weight of cement, 30-42 parts by weight of composite ash, 230-300 parts by weight of crushed stone, 120-150 parts by weight of sand, 1-1.2 parts by weight of water-reducing agent, and 2-5 parts by weight of phase change material.

[0009] According to an embodiment of the present invention, the cement in the raw materials is selected from silicate cement. Preferably, the strength grade of the cement is not less than PO 52.5, for example, PO 60 or PO 70.

[0010] According to an embodiment of the present invention, the composite ash in the raw material comprises fly ash and steel slag ash. Further, the mass ratio of fly ash to steel slag ash is 1:1 to 3:2, for example, 1.5:1, 2:1, 1.5:2, 1.5:3, 2:2, or 3:1.5.

[0011] According to an embodiment of the present invention, the parameters of the crushed stone in the raw material are as follows: mud content ≤0.3%, for example 0.1% or 0.2%; nominal particle size 5-25mm, for example 10mm or 20mm.

[0012] According to an embodiment of the present invention, the parameters of the sand in the raw material are as follows: mud content ≤0.7%, for example 0.1%, 0.3%, 0.5%; fineness modulus 3.7-1.6, for example 2.3.

[0013] According to an embodiment of the present invention, the water-reducing agent is selected from polycarboxylate superplasticizers. Preferably, the polycarboxylate superplasticizer can be any polycarboxylate superplasticizer known in the art, and no specific limitation is made in this invention. Exemplarily, the polycarboxylate superplasticizer is, for example, a powdered polycarboxylate superplasticizer (e.g., purchased from Shandong Fuke Chemical).

[0014] According to an embodiment of the present invention, the raw materials further include water. Preferably, the mass ratio of water to cement is 1:(0.61-1), more preferably 1:0.65-0.70.

[0015] According to an embodiment of the present invention, the composite fiber is obtained by mixing a phase change material and a resin.

[0016] According to an embodiment of the present invention, the composite fiber has a length of 1-10 mm (preferably 3-9 mm, for example 6 mm) and a diameter of 0.05 mm-0.5 mm (preferably 0.1-0.2 nm, for example 0.16 nm).

[0017] According to an embodiment of the present invention, the resin is selected from PA6.

[0018] According to an embodiment of the present invention, the mass ratio of the phase change material to the resin is 1:100-400, for example, 1:180.

[0019] According to an embodiment of the present invention, the phase change material is selected from nano-metal-modified polydopamine / paraffin phase change microcapsules.

[0020] Preferably, the nano-copper atom modified polydopamine / paraffin phase change microcapsules are prepared by reacting paraffin, dopamine solution, and copper nitrate solution.

[0021] Furthermore, the preparation method of the nano-copper atom-modified polydopamine / paraffin phase change microcapsules includes the following steps:

[0022] A1) Preparation of dopamine solution: Obtain dopamine solution by mixing acidic buffer solution and dopamine source;

[0023] A2) Add the mixed emulsifier to the molten paraffin, then add the dopamine solution from step A1) and stir to form the first emulsion;

[0024] A3) After adding copper nitrate solution to the first emulsion in step A2), stir to form a second emulsion;

[0025] A4) Let the second emulsion stand until it separates into layers. Take the microcapsule layer (i.e., the lower precipitate layer), filter it under reduced pressure, wash it, and dry it under vacuum to obtain nano-copper atom modified polydopamine / paraffin phase change microcapsules.

[0026] Specifically, in step A1), the mass concentration of dopamine in the dopamine solution is 0.1 to 5 g / L, for example, 2 g / L.

[0027] Specifically, in step A1), the acidic buffer is selected from acidic buffers known in the art, such as hydrochloric acid buffer, like tris-HCl buffer (Tris-HCl buffer).

[0028] Specifically, in step A1), the dopamine source is selected from dopamine hydrochloride.

[0029] Specifically, in step A1), an alkaline regulator is further added to the dopamine solution to adjust the pH value of the dopamine solution to be greater than 7, preferably greater than 8, for example, 8.5. Further, the alkaline regulator is selected from substances known in the art, such as sodium hydroxide solution.

[0030] Specifically, in step A2), the amount of the mixed emulsifier is 1-20%, for example, 10%.

[0031] Specifically, the mixed emulsifier includes at least one or both of Span 80 and op-10. For example, the mixed emulsifier includes Span 80 and op-10 in a mass ratio of 0.5-1.5:2-4, for example, 1:3.

[0032] Specifically, the paraffin in the molten paraffin is selected from phase change paraffins, such as paraffin with a melting point of 36°C.

[0033] Specifically, in step A2), the mass ratio of the molten paraffin and the mixed emulsifier is 1:0.05 to 0.15, for example, 1:0.1.

[0034] Furthermore, in step A2), the stirring conditions are: room temperature, stirring speed of 400r / min-600r / min, and stirring time of 3-4h.

[0035] Specifically, in step A3), the amount of copper nitrate solution added is 10-50% of the total volume of the first emulsion, for example, 30%.

[0036] Specifically, in the copper nitrate solution, the mass ratio of copper nitrate to water is 0.1-1.5:1-5, for example, 1:2.

[0037] Further, in step A3), the stirring conditions are: stirring at room temperature at a speed of 10-100 r / min (e.g., 50 r / min) for 10-30 h (e.g., 24 h).

[0038] Specifically, in step A3), the washing can be performed using methods known in the art, such as washing twice with ethanol and hot water at 40°C.

[0039] According to an exemplary embodiment of the present invention, the composite fiber is a composite short fiber produced by a core-sheath composite spinning method, the composite short fiber comprising a sheath and a core, wherein the sheath comprises the phase change material and the resin; and the core is selected from PET.

[0040] Preferably, in the composite short fiber, the mass ratio of the sheath to the core layer is 0.1-2:0.1-2, for example, 1:1.

[0041] For example, the composite short fiber is a PA6 / PET composite short fiber, which is prepared by a skin-core composite material containing phase change material as the skin layer and PET as the core layer through a skin-core composite spinning method.

[0042] More preferably, the method for preparing PA6 / PET composite short fibers includes the following steps:

[0043] B1) PA6-based composite material chips and PET are melt-extruded into the composite spinning box by two screw extruders respectively, and then merged at the spinneret inlet and extruded together;

[0044] B2) After cooling, winding, stretching, shaping and cutting, PA6-based composite material / PET composite short fiber is obtained.

[0045] According to an embodiment of the present invention, in step B1), the PA6-based composite material slice refers to the slice obtained by mixing the phase change microcapsules and PA6 resin.

[0046] Preferably, in the PA6-based composite material slices, the mass ratio of phase change microcapsules to PA6 resin is 1:100-1:230, for example, 1:180;

[0047] According to an embodiment of the present invention, in step B1), the mass ratio of the PA6-based composite material slices to the PET slices is 0.1-2:0.1-2, for example, 1:1;

[0048] According to an embodiment of the present invention, in step B2), the length of the PA6-based composite material / PET composite short fiber is 3 to 9 mm, for example, 6 mm; the diameter of the fiber is 0.1 to 0.2 nm, for example, 0.18 nm.

[0049] This invention also provides a method for preparing the above-mentioned concrete material, the method comprising the following steps:

[0050] 1) According to the raw material mass proportions of concrete materials, the composite ash and sand are mixed until uniform, and then quickly mixed to obtain the first mixture;

[0051] 2) Dissolve the water-reducing agent in the first part of water according to the mass of the raw materials of the concrete material, stir it evenly, and then add it to the first mixture in step 1) in two batches. Stir quickly after each addition to obtain the second mixture.

[0052] 3) According to the raw material weight proportions of concrete materials, add cement, crushed stone and the second part of water to the second mixture in step 2) in sequence, and stir quickly;

[0053] 4) After adding PA6 / PET composite short fibers, stir quickly to obtain concrete composite material.

[0054] According to an embodiment of the present invention, the total amount of the first part of water and the second part of water is in a mass ratio of cement to 1:(0.61~1), preferably 1:0.65~0.70.

[0055] According to an embodiment of the present invention, in steps 2), 3), and 4), the rapid stirring time is no more than 60 seconds, for example, 50 seconds, 5 seconds, and 20 seconds.

[0056] This invention provides the application of the above-mentioned concrete material in the construction field, such as for the construction of energy storage walls and energy-saving buildings.

[0057] The beneficial effects of this invention are as follows:

[0058] The concrete material of the present invention improves the thermal conductivity and utilization rate of the phase change material by introducing nano-metal particles into the phase change material. It combines composite fibers as toughening units with the phase change material, reducing the number of loosely bonded units in the concrete material, so that the strength of the concrete material is not seriously affected. At the same time, it ensures the thermal insulation effect of the concrete material and enhances the toughness of the concrete material, thereby improving the overall performance of the phase change concrete material. Detailed Implementation

[0059] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0060] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0061] Preparation Example 1

[0062] The preparation method of polydopamine / paraffin phase change microcapsules modified with nano-copper atoms is as follows:

[0063] A1) Tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) and dopamine hydrochloride were dissolved in deionized water. The pH of the solution was adjusted to 8.5 with sodium hydroxide under magnetic stirring to obtain a 2 g / L dopamine solution.

[0064] A2) Take 10% of the mixed emulsifier, and the components and their proportions of the mixed emulsifier are m 司班80 :m op-10 = 1:3, the mass ratio of molten paraffin and mixed emulsifier is 1:0.1, and the mixture is stirred at 500 r / min for 3 h at room temperature to obtain the first emulsion;

[0065] After stirring A3), add 30% of the mass of the first emulsion with copper nitrate solution (copper nitrate: water = 1:2) and add it to the first emulsion in A2). Stir at 50 r / min for 24 h to obtain the second emulsion.

[0066] A4) Let the second emulsion stand until it separates into layers. Take the microcapsule layer (lower precipitate layer) and filter it under reduced pressure. Wash it twice with ethanol and hot water at 40°C, and then dry it under vacuum to obtain nano-copper atom modified polydopamine / paraffin phase change microcapsules.

[0067] Preparation Example 2

[0068] The preparation method of PA6-based material / PET composite short fiber is as follows:

[0069] B1) Based on the ratio of phase change microcapsules to PA6 resin = 1:180 (mass ratio), mix nano-copper atom-modified polydopamine / paraffin phase change microcapsules and PA6 resin, and then draw them into fibers and granulate them to obtain PA6-based composite material.

[0070] B2) According to the mixing mass ratio of PA6-based composite material chips: PET chips = 1:1, PA6-based composite material and PET are added to two screw extruders respectively. The materials melt and enter the composite spinning box, and are extruded together after converging at the spinneret inlet.

[0071] B2) After cooling, winding, stretching, shaping and cutting, PA6-based composite material / PET composite short fiber is obtained, with a fiber length of 6 mm and a diameter of 0.16 mm.

[0072] Preparation Example 3

[0073] The preparation of PA6 / PET composite short fibers is basically the same as in Preparation Example 2, except that PA6 resin without phase change microcapsules is used, as detailed below:

[0074] According to the mixing mass ratio of PA6 resin to PET resin = 1:1, PA6-based composite material and PET are added to two screw extruders respectively. The materials melt and enter the composite spinning box, and are extruded together at the inlet of the spinneret. After cooling, winding, stretching, shaping and cutting, PA6 / PET composite short fibers are obtained with a fiber length of 6mm and a diameter of 0.16mm.

[0075] Preparation Example 4

[0076] The preparation method of polydopamine / paraffin phase change microcapsules is as follows:

[0077] A1) Tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) and dopamine hydrochloride were dissolved in deionized water. The pH of the solution was adjusted to 8.5 with sodium hydroxide under magnetic stirring to obtain a 2 g / L dopamine solution.

[0078] A2) Take 10% of the mixed emulsifier, and the components and their proportions of the mixed emulsifier are m 司班80 :m op-10 = 1:3, the mass ratio of molten paraffin and mixed emulsifier is 1:0.1, and the mixture is stirred at 500 r / min for 3 h at room temperature to obtain the first emulsion;

[0079] A3) Let the first emulsion stand until it separates into layers. Take the microcapsule layer (lower precipitate layer) and filter it under reduced pressure. Wash it twice with ethanol and hot water at 40°C, respectively. Dry it under vacuum to obtain polydopamine / paraffin phase change microcapsules.

[0080] Example 1

[0081] 1. The raw materials for preparing cement-based composite materials include at least cement, composite ash, crushed stone, sand, water-reducing agent, and composite short fiber;

[0082] The mass ratio of cement, composite ash (fly ash and steel slag ash in a 1:1 ratio), crushed stone, sand, water-reducing agent, and composite short fiber is 1:35:250:150:1:3.

[0083] The specific parameters of the above-mentioned raw materials are as follows:

[0084] 1) Cement: Silicate cement, strength grade PO 52.5;

[0085] 2) Sand: Fineness modulus 2.3, mud content ≤0.7% is acceptable;

[0086] 3) Crushed stone: mud content ≤0.3%, nominal particle size 5-25mm;

[0087] 4) Water-reducing agent: Powdered polycarboxylate high-efficiency water-reducing agent, purchased from Shandong Fuke Chemical;

[0088] 5) Composite short fiber: Prepare PA6-based material / PET composite short fiber as in Example 2.

[0089] 2. Preparation of tough concrete material, the preparation method includes the following steps:

[0090] 1) After the composite ash and sand are stirred until uniform, the mixture is quickly stirred to obtain the first mixture;

[0091] 2) Dissolve the water-reducing agent in water and stir evenly, then add it to the first mixture in step 1) in two batches, stirring quickly for 30 seconds after each addition to obtain the second mixture;

[0092] 3) Add cement, crushed stone and water to the second mixture in step 2) in sequence, and stir quickly for 30 seconds;

[0093] 4) After adding PA6 / PET composite short fibers, stir quickly for 50 seconds to obtain concrete mixture;

[0094] 5) Pour the mixed concrete into the test mold in two batches, and compact the concrete after each pour. The test mold size is 40mm×40mm×160mm.

[0095] 6) After 12 hours, remove the sample from the mold and cure it for the required age for testing. The relative humidity for curing is 90% and the temperature is 20±2℃.

[0096] The mechanical strength of the test specimens was tested according to GB 17671-1999.

[0097] Comparative Example 1:

[0098] 1. Prepare the raw materials for the composite material. The raw materials and their mass ratios are basically the same as in step 1 of Example 1. The difference is that PA6 / PET composite short fibers from Preparation Example 3 are used, and phase change microcapsules from Preparation Example 1 are added to the raw materials. That is, the mass ratio of cement, composite ash (the mass ratio of fly ash and steel slag ash is 1:1), crushed stone, sand, water-reducing agent, and PA6 / PET composite short fibers in the raw materials is 1:35:250:150:1:3, and the mass ratio of phase change microcapsules to PA6 resin is 1:180.

[0099] 2. Preparation of high-toughness concrete: The preparation method is basically the same as step 2 in Example 1. The difference is that the raw materials in step 1 of this comparative example are used, that is, PA6 / PET composite short fibers and phase change microcapsules are added to the concrete mixture as raw materials.

[0100] Comparative Example 2

[0101] 1. The mass ratio of the raw materials for preparing the composite material is basically the same as step 1 in Example 1. The difference is that the PA6-based material / PET composite short fiber of Preparation Example 2 is not added, and the phase change microcapsules of Preparation Example 1 are added to the raw materials. That is, the mass ratio of cement, composite ash (the mass ratio of fly ash and steel slag ash is 1:1), crushed stone, sand, water-reducing agent and phase change microcapsules in the raw materials is 1:35:250:150:1:3.

[0102] 2. Preparation of high-toughness concrete is basically the same as step 2 in Example 1, except that the raw materials in step 1 of this comparative example are used, that is, the phase change microcapsules are directly added to the concrete mixture.

[0103] Comparative Example 3

[0104] 1. Prepare the raw materials for the composite material. This comparative example is basically the same as step 1 of comparative example 1, except that the phase change microcapsules are replaced with the phase change microcapsules of preparation example 4.

[0105] 2. Preparation of high-toughness concrete. The preparation method is basically the same as step 2 in Comparative Example 1, except that the raw materials in step 1 of this Comparative Example are used.

[0106] Comparative Example 4

[0107] 1. The mass ratio of the raw materials for preparing the composite material is basically the same as that in step 1 of Example 1. The difference is that the mass ratio of cement, composite ash (the mass ratio of fly ash and steel slag ash is 1:1), crushed stone, sand, water-reducing agent and phase change microcapsules is 1:35:250:150:1:10.

[0108] Test case

[0109] The mechanical strength of the test specimens was tested according to GB 17671—1999. Small test chambers were constructed using concrete from Example 1 and Comparative Example 1-2, respectively. The temperature changes inside and outside the test chambers were detected in the same environment. The test results of Example 1 and Comparative Example 1-2 are shown in Table 1.

[0110] Table 1 Test Results

[0111]

[0112] The test results above show that:

[0113] Comparing the test results of Example 1 and Comparative Example 1, it was found that adding phase change microcapsules and short fibers to concrete resulted in a 4.5% decrease in compressive strength compared to the concrete strength of Example 1. This is because the phase change microcapsules and composite short fibers form two independent phases in the concrete, and the bonding strength between the phase change microcapsules and concrete is not very high, which can easily have an adverse effect on the mechanical properties of concrete. The temperature difference between the inner and outer walls of the walls in Example 1 and Comparative Example 1 was only 0.6℃, indicating that combining phase change microcapsules with the toughening component composite short fibers does not significantly affect the thermal insulation performance of phase change concrete.

[0114] Comparing the test results of Example 1 and Comparative Example 2, the flexural strength of the concrete with added composite short fibers increased by 7.1%, indicating that adding an appropriate amount of composite short fibers can improve the toughness of concrete while ensuring thermal insulation performance.

[0115] Comparing the test results of Example 1 and Comparative Example 3, the phase change microcapsules modified with nano-metal particles can exhibit better energy storage and thermal insulation effects in concrete matrices. This is because nano-metal particles can improve the thermal conductivity of the fiber skin, enabling the phase change material to effectively perform its energy storage function within the fiber matrix.

[0116] Comparing the test results of Example 1 and Comparative Example 4, adding more phase change material can improve the thermal insulation effect of concrete, but the flexural strength improvement effect of Example 1 is better than that of Comparative Example 4. Although increasing the amount of phase change material can improve the thermal insulation effect of concrete, too many phase change microcapsule units will lead to the performance incoordination of the core-skin structure of composite short fibers, and the toughening effect of composite fibers will decrease.

[0117] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A concrete material, characterized in that, The raw materials of the concrete material include at least cement, composite ash, crushed stone, sand, water-reducing agent, and composite fiber; the composite fiber is a composite short fiber produced by a core-sheath composite spinning method, the composite short fiber includes a sheath and a core, wherein the sheath includes a phase change material and a resin; the core is selected from PET; The raw materials comprise, per 100 parts by weight of cement: 100 parts by weight of cement, 30-42 parts by weight of composite ash, 230-300 parts by weight of crushed stone, 120-150 parts by weight of sand, 1-1.2 parts by weight of water-reducing agent, and 2-5 parts by weight of composite short fiber; The phase change material is selected from nano-copper atom modified polydopamine / paraffin phase change microcapsules; The nano-copper atom modified polydopamine / paraffin phase change microcapsules were prepared by reacting paraffin, dopamine solution, and copper nitrate solution. The preparation method of the nano-copper atom modified polydopamine / paraffin phase change microcapsules includes the following steps: A1) Preparation of dopamine solution: A dopamine solution is obtained by mixing an acidic buffer solution and a dopamine source; the mass concentration of dopamine in the dopamine solution is 0.1~5 g / L; the dopamine source is selected from dopamine hydrochloride; an alkaline regulator is further added to the dopamine solution to adjust the pH value of the dopamine solution to be greater than 7; A2) Add the mixed emulsifier to the molten paraffin, then add the dopamine solution from step A1) and stir to form a first emulsion; the amount of the mixed emulsifier is 1-20%; the mixed emulsifier includes at least one or two of Span 80 and OP-10; the paraffin in the molten paraffin is selected from phase change paraffin; the mass ratio of the molten paraffin to the mixed emulsifier is 1:0.05~0.15; A3) After adding copper nitrate solution to the first emulsion in step A2), the mixture is stirred to form a second emulsion; the amount of copper nitrate solution added is 10-50% of the total volume of the first emulsion. A4) Let the second emulsion stand until it separates into layers. Take the microcapsule layer, filter under reduced pressure, wash, and vacuum dry to obtain nano-copper atom modified polydopamine / paraffin phase change microcapsules.

2. The concrete material according to claim 1, characterized in that, In the raw materials, the cement is selected from silicate cement; The components of the composite ash in the raw materials include fly ash and steel slag ash; The parameters of the crushed stone in the raw materials are as follows: mud content ≤0.3%; nominal particle size 5-25mm; The raw material, the sand, has the following parameters: mud content ≤ 0.7%; fineness modulus 3.7-1.

6.

3. The concrete material according to claim 1, characterized in that, The raw materials also include water, and the mass ratio of water to cement is 1:0.61~1.

4. The concrete material according to claim 1, characterized in that, The composite fiber has a length of 1-10 mm and a diameter of 0.05 mm-0.5 mm.

5. The concrete material according to claim 1, characterized in that, In the composite short fiber, the mass ratio of the cortex to the core layer is 0.1-2:0.1-2.

6. The concrete material according to claim 1, characterized in that, The resin is selected from PA6.

7. The concrete material according to claim 1, characterized in that, The mass ratio of the phase change material to the resin is 1:100-400.

8. A method for preparing the concrete material according to claim 6, characterized in that, The preparation method includes the following steps: 1) According to the raw material mass proportions of concrete materials, the composite ash and sand are mixed until uniform, and then quickly stirred to obtain the first mixture; 2) Dissolve the water-reducing agent in the first part of water according to the raw material mass of the concrete material, stir evenly, and add it to the first mixture in step 1) in two batches. Stir quickly after each addition to obtain the second mixture. 3) According to the raw material weight proportions of concrete materials, add cement, crushed stone and the second part of water to the second mixture in step 2) in sequence, and stir quickly; 4) After adding the composite short fibers, stir quickly to obtain the concrete composite material.

9. The preparation method according to claim 8, characterized in that, The total amount of the first and second portions of water, in mass ratio to the cement, is 1:0.61~1; In steps 2), 3), and 4), the rapid stirring time should not exceed 60 seconds.

10. The application of the concrete material according to any one of claims 1-7 in the construction field.

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