A composite biomimetic tough aluminate cement-based material and a preparation method thereof

Abstract

The application discloses a kind of composite biomimetic tenacious aluminate cement-based materials and preparation method thereof, the aluminate cement-based material is formed by arranging and hot-pressing several semi-dry particles, the structure of the arrangement includes a layer of a layer by a particle size particle paving, a layer by b particle size particle paving is paved on the a layer, a layer by c particle size particle paving is paved on the b layer, wherein a particle size, b particle size and c particle size are all different;The components of the semi-dry particles include, by weight fraction, 500 parts of cement, 80 parts of water, 0-30 parts of PVA, 0-5 parts of glycerol, 0-60 parts of Fe3O4.The method prepares semi-dry particles by adjusting the mix proportion of cement material and re-arranges hot-pressing to form gradient "brick-mud" structure, simple operation, controllable cost, easy to realize, the tensile strength and flexural toughness of the obtained cement-based board material are greatly improved compared with the control group, and the high-strength and high-toughness cement-based material can cover a wider range of applications.

Description

Technical Field

[0001] This invention relates to an aluminate cement-based material and its preparation method, and more particularly to a composite biomimetic aluminate cement-based material with high toughness and its preparation method, belonging to the field of civil engineering materials. Background Technology

[0002] Cement-based materials are the most widely used materials in the world besides water due to their low cost, high plasticity, and wide range of applications. However, cement-based composites still have several significant drawbacks. As a non-idealized homogeneous composite material, cement-based composites inherently exhibit quasi-brittleness, with low flexural and tensile strength, poor toughness, and brittle cracking. These inherent drawbacks greatly limit the application range of cement-based materials. Therefore, toughening cement-based composites is a cutting-edge research area and a key objective in concrete science and technology.

[0003] Currently, toughening methods for concrete and cement composites generally fall into three categories: adding PVA, PP, steel fibers, polymer emulsions or monomers, and modification with nanomaterials such as whiskers, carbon nanotubes, and graphene. However, all three toughening methods have drawbacks, such as difficulty in achieving uniform mixing and high cost. Furthermore, the reinforcing phase is typically bonded to the cement matrix through simple blending, resulting in limited toughening effects. In contrast, organisms in nature have developed high-performance gradient structures that achieve excellent flexural strength and toughness through differences in gradient arrangement. A similar strategy is used in baleen plates to achieve good mechanical properties. However, research on similar biomimetic gradient structures in the field of cement-based materials is relatively limited, yet it represents a research direction full of unlimited potential.

[0004] Based on the above background, this paper uses the optimized experimental mix ratio to prepare semi-dry particles and designs a series of semi-dry particle arrangements inspired by gradient biomimetic schemes in order to find an arrangement that can better improve bending strength and toughness. This biomimetic structure toughening effect can make the same material have a significant improvement in mechanical properties, so as to achieve a wider range of practical applications. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a composite biomimetic aluminate cement-based material with high toughness; another purpose of this invention is to provide a method for preparing the composite biomimetic aluminate cement-based material with high toughness.

[0006] Technical Solution: The present invention provides a composite biomimetic aluminate cement-based material with high toughness. The aluminate cement-based material is formed by hot pressing a plurality of semi-dry particles arranged in a specific pattern. The arrangement structure includes a layer a composed of particles of diameter a, a layer b composed of particles of diameter b, and a layer c composed of particles of diameter c. The particle diameters a, b, and c are all different. The semi-dry particles are composed of, by weight fraction, 500 parts cement, 80 parts water, 0-30 parts PVA, 0-5 parts glycerol, and 0-60 parts Fe3O4.

[0007] Preferably, the semi-dry granules comprise, by weight fraction, 500 parts cement, 80 parts water, 15-30 parts PVA, 2.5-5 parts glycerol, and 30-60 parts Fe3O4.

[0008] Furthermore, the arrangement structure also includes a d layer composed of d-sized particles laid flat, with the d layer located below the a layer or above the c layer.

[0009] Preferably, particle size b > particle size c > particle size d > particle size a, or particle size a > particle size c > particle size b > particle size d.

[0010] On the other hand, the present invention provides a method for preparing a composite biomimetic tough aluminate cement-based material, comprising the following steps:

[0011] (1) Add 0-5 parts of glycerol to 80 parts of water to obtain a glycerol solution; after mixing 500 parts of cement, 0-30 parts of PVA and 0-60 parts of Fe3O4 evenly, add the glycerol solution and mix evenly to obtain a semi-dry cement mixture.

[0012] (2) The above semi-dry cement mixture is made into several semi-dry particles according to particle size a, particle size b and particle size c; a layer of particles of particle size a is laid flat to form layer a, a layer of particles of particle size b is laid flat on layer a to form layer b, and a layer of particles of particle size c is laid flat on layer b to form layer c; layer a, layer b and layer c are hot-pressed.

[0013] (3) After hot pressing, the finished product is taken out and cured; after curing, the aluminate cement-based material is obtained.

[0014] Preferably, in step (1), the glycerol solution is prepared at room temperature.

[0015] Further, in step (2), the above semi-dry cement mixture is made into several semi-dry particles according to particle size a, particle size b, particle size c and particle size d; a layer of particles of particle size a is laid flat to form layer a, a layer of particles of particle size b is laid flat on layer a to form layer b, a layer of particles of particle size c is laid flat on layer b to form layer c, and a layer of particles of particle size d is laid flat on layer c to form layer d; layers a, b, c and d are hot-pressed.

[0016] Preferably, in step (2), particle size b > particle size c > particle size d > particle size a, or particle size a > particle size c > particle size b > particle size d.

[0017] Furthermore, in step (2), the hot pressing temperature for hot pressing is 80-90℃.

[0018] Furthermore, in step (3), the curing temperature is 60-70℃.

[0019] Preferably, the D of aluminate cement 10 It is 2.063 μm, D 50 It is 13.841 μm, D 90 The particle size is 45.034 μm, the average particle size is 20.288 μm, and the distribution range is ((D 90 -D 10 ) / D 50 The value is 3.105.

[0020] Preferably, the PVA powder is 125 mesh with a degree of alcoholysis of 88%.

[0021] Preferably, the Fe3O4 powder is a black powder with a particle size of 800 mesh, a purity of 99.9%, and a bulk density of 5.18 g / cm³. 3 Its crystal form is inverted spinel.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1) The method uses crushed semi-dry cement particles to imitate the "brick-mud" structure of the mother-of-pearl, and at the same time, it achieves the imitation of the gradient structure in nature through the optimization of particle rearrangement. This not only ensures the high strength of cement-based composite materials, but also solves the problem of reduced toughness caused by the increase in strength.

[0023] 2) This method utilizes hot pressing to achieve rapid strength formation of aluminate cement, and the rapid turnover of molds also significantly shortens the cycle from processing and molding to use.

[0024] 3) The composite biomimetic method for improving the strength and toughness of aluminate cement-based materials provided by this invention requires fewer raw materials, has a simple mixing ratio, is easy to operate, has controllable costs, and is easy to implement. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the particle arrangement of the present invention;

[0026] Figure 2 The different mixing ratios in Example 1 demonstrate the strength and toughness effects.

[0027] Figure 3 The different arrangements in Example 2 demonstrate the strong and tough effects. Detailed Implementation

[0028] The embodiments given below are intended to further illustrate the present invention, but should not be construed as limiting the scope of protection of the present invention. Further non-substantial improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0029] like Figure 1 As shown, this embodiment of the invention provides a composite biomimetic aluminate cement-based material with high toughness. The aluminate cement-based material is formed by hot pressing a plurality of semi-dry particles arranged in a specific pattern. The arrangement structure includes a layer a composed of particles of diameter a, a layer b composed of particles of diameter b, and a layer c composed of particles of diameter c. The particle diameters a, b, and c are all different. The semi-dry particles are composed of, by weight fraction, 500 parts cement, 80 parts water, 0-30 parts PVA, 0-5 parts glycerol, and 0-60 parts Fe3O4.

[0030] Example 1:

[0031] A method for preparing a composite biomimetic tough aluminate cement-based material includes the following steps:

[0032] 1) First, add the powder shown in Table 1 into a 3L container and stir with a whisk. Stir at low speed for 60 seconds, then add the glycerol solution according to the mixing ratio and stir at high speed for 120 seconds to obtain a semi-dry cement mixture.

[0033] Table 1. Mix proportion study of a composite biomimetic method for improving the strength and toughness of aluminate cement-based materials.

[0034]

[0035]

[0036] 2) Add the semi-dry cement mixture to a roller and roll it to a thickness of less than 1 mm. After rolling for about 180 seconds, remove the mixture and crush it into granules using a whisk at high speed. Pour the granules into a mold and then use a hot press to maintain a temperature of 80℃ and a pressure of 15MPa for 20 minutes.

[0037] 3) Remove the hot-pressed sample and place it in an oven for curing at 60℃ for 1 day. After curing, remove the sample and cut it into appropriate sizes, ensuring the surface is flat. Use a universal testing machine to perform a three-point bending test on the specimen to obtain its tensile strength and toughness.

[0038] Comparison of strength and toughness of aluminate cement laminates with different mix proportions is as follows: Figure 2 As shown. In a composite biomimetic tough aluminate cement-based material, the optimal proportion of the semi-dry particle components is 2.5g glycerol, 80g water, 500g aluminate cement, 30g Fe3O4 powder, and 15g PVA powder.

[0039] Example 2:

[0040] A method for preparing a composite biomimetic tough aluminate cement-based material includes the following steps:

[0041] 1) Dissolve 2.5g of glycerol in 80g of water and disperse it by ultrasonication for later use. Add 500g of aluminate cement, 30g of Fe3O4 powder and 15g of PVA to a 3L container and stir with a whisk. First, stir at low speed for 60s, then add the glycerol solution and stir at high speed for 120s to obtain a semi-dry cement mixture.

[0042] 2) Add the semi-dry cement mixture to a roller and roll it, ensuring the rolling thickness is within 1mm. After rolling for approximately 180 seconds, remove the mixture and crush it into granules using a high-speed whisk. Use a sieve and vibrating screen to screen the granules, labeling them with codes 0, 1, 2, and 3 to represent granules with diameters of approximately 0.5mm, 1mm, 2mm, and 3mm respectively. Arrange the granules appropriately (e.g., 0123 represents granules arranged in the order of 0.5mm, 1mm, 2mm, and 3mm), and then use a hot press at 80℃ and 15MPa for 20 minutes.

[0043] 3) Remove the hot-pressed sample and place it in an oven for curing at 60℃ for 1 day. After curing, remove the sample and cut it into appropriate sizes, keeping the surface flat.

[0044] 4) The specimen was subjected to a three-point bending test using a universal testing machine to obtain its tensile strength and toughness.

[0045] Comparison of strength and toughness of aluminate cement biomimetic laminate structures with different arrangements is as follows: Figure 2 As shown in the figure, the 0312 arrangement exhibits high strength (34.30 MPa) and excellent toughness (21.70 kJ / m). 3Its strength exceeds that of the control groups 0000, 1111, 2222, and 3333 with a single particle size but without composite biomimetic arrangement, by 144.1%, 142.6%, 146.6%, and 142.6% respectively, and even 213.6% of the strength of the experimental group 1320; its toughness far exceeds that of the control groups 0000, 1111, 2222, and 3333 with a single particle size but without composite biomimetic arrangement, by 177.4%, 182.8%, 210.6%, and 211.3% respectively, and is 314.5% of the toughness of the experimental group 1032.

Claims

1. A composite biomimetic aluminate cement-based material with high toughness, characterized in that, The aluminate cement-based material is formed by hot pressing a plurality of semi-dry particles arranged in a specific structure. The arrangement includes a layer a composed of particles of diameter a, a layer b composed of particles of diameter b, a layer c composed of particles of diameter c, and a layer d composed of particles of diameter d. The arrangement also includes a layer d composed of particles of diameter d. The layer d is located below the layer a, with particle diameter b > particle diameter c > particle diameter d > particle diameter a; or the layer d is located above the layer c, with particle diameter a > particle diameter c > particle diameter b > particle diameter d. The particle diameters a, b, and c are all different. The semi-dry particles are composed of, by weight, 500 parts cement, 80 parts water, 0-30 parts PVA, 0-5 parts glycerol, and 0-60 parts Fe3O4, wherein the weight parts of PVA, glycerol, and Fe3O4 are all not zero.

2. A method for preparing a composite biomimetic aluminate cement-based material with high toughness, characterized in that, Includes the following steps: (1) Add 0-5 parts of glycerol to 80 parts of water to obtain a glycerol solution; after mixing 500 parts of cement, 0-30 parts of PVA and 0-60 parts of Fe3O4 evenly, add the glycerol solution and mix evenly to obtain a semi-dry cement mixture, wherein the weight parts of PVA, glycerol and Fe3O4 are not 0. (2) The above semi-dry cement mixture is made into several semi-dry particles according to particle size a, particle size b, particle size c and particle size d; a layer of particles of particle size a is laid flat to form layer a, a layer of particles of particle size b is laid flat on layer a to form layer b, a layer of particles of particle size c is laid flat on layer b to form layer c; a layer of particles of particle size d is laid flat on layer c to form layer d, and particle size a > particle size c > particle size b > particle size d; or layer d is set below layer a, and particle size b > particle size c > particle size d > particle size a; layer a, layer b, layer c and layer d are hot-pressed. (3) After hot pressing, the finished product is taken out and cured; after curing, the aluminate cement-based material is obtained.

3. The method for preparing the composite biomimetic tough aluminate cement-based material according to claim 2, characterized in that, In step (1), the glycerol solution is prepared at room temperature.

4. The method for preparing the composite biomimetic tough aluminate cement-based material according to claim 2, characterized in that, In step (2), the hot pressing temperature is 80-90℃.

5. The method for preparing the composite biomimetic tough aluminate cement-based material according to claim 2, characterized in that, In step (3), the curing temperature is 60-70℃.

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