High-toughness cement-polymer composite material and preparation method thereof

Abstract

The invention discloses a high-toughness cement-polymer composite material and a preparation method thereof, and belongs to the technical field of cement materials. The high-toughness cement-polymer composite material comprises a plurality of stacked cement sheets, the cement sheets are bonded and connected through a polymer, each cement sheet comprises a plurality of cement sub-sheets, and the included angle between the cement sub-sheets of the adjacent cement sheets is 10-90 degrees. The upper surfaces of the cement sheets are coated with polymers, the cement sheets on the upper layer are assembled on the cement sheets, the cement sheets are sequentially and repeatedly assembled till the set number of layers is reached, and a composite material blank is obtained. By adopting the high-toughness cement-polymer composite material and the preparation method thereof, the problem of poor toughness of an existing cement-based material can be solved.

Description

Technical Field

[0001] This invention relates to the field of cement materials technology, and in particular to a high-toughness cement-polymer composite material and its preparation method. Background Technology

[0002] Cement-based materials, with their advantages of wide availability, low cost, and high compressive strength, are among the most widely used building materials and play a vital role in various infrastructure constructions. With the rapid development of infrastructure construction in my country, projects are increasingly expanding into complex environments such as high mountains and deep underground, placing higher demands on the performance of cement-based materials. However, traditional cement-based materials generally suffer from high brittleness and insufficient flexural toughness, making them prone to cracking and brittle failure under complex stress conditions, thus limiting their widespread application in high-performance structural engineering.

[0003] To improve the toughness of cement-based materials, existing technologies mainly employ two toughening approaches: one is fiber reinforcement, which involves incorporating fibers (such as steel fibers, polypropylene fibers, and carbon fibers) into the cement matrix, utilizing the interfacial bonding between the fibers and the matrix to inhibit crack initiation and propagation; the other is polymer modification, which involves introducing polymer emulsions or resins into the cement matrix, allowing the polymer to form a three-dimensional network structure within the matrix, thereby improving the material's flexibility and interfacial bonding performance. While these technologies can alleviate the brittleness of cement-based materials to some extent, they still have significant limitations: the crack propagation inhibition effect of fiber reinforcement is mainly concentrated in localized areas, making it difficult to achieve a synergistic improvement in the overall toughness of the material; although polymer modification can improve matrix flexibility, its effect on improving the overall toughness is limited due to the compatibility and uniform distribution of the polymer with cement hydration products. It ultimately cannot overcome the inherent limitation of the inherent brittleness of the cement matrix itself, making it difficult to meet the toughness requirements of high-performance structural engineering in complex environments.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a high-toughness cement-polymer composite material and its preparation method, thereby solving the problem of poor toughness in existing cement-based materials.

[0006] To achieve the above objectives, the present invention provides a high-toughness cement-polymer composite material comprising a plurality of stacked cement sheets, which are bonded together by polymer. Each cement sheet includes a plurality of cement sub-sheets, and the included angle between the cement sub-sheets of adjacent cement sheets is 10°-90°.

[0007] Preferably, the cement sheet has 8-15 layers and a thickness of 2mm-4mm.

[0008] Preferably, the polymer is epoxy resin or polyurethane, and the thickness of the polymer is 0.7mm-1mm.

[0009] Preferably, the epoxy resin is one or more of bisphenol A type epoxy resin, phenolic epoxy resin, and alicyclic epoxy resin; the polyurethane is one or more of polyester type polyurethane, polyether type polyurethane, and polycarbonate type polyurethane.

[0010] Preferably, the cement flakes comprise the following components in parts by weight: 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, and 15 parts fiber; the polymer between the cement flakes is 10-20 parts.

[0011] Preferably, the silicate cement is P·Ⅱ52.5 silicate cement, with cement clinker and gypsum content greater than or equal to 95% and limestone content less than or equal to 5%; the sulfoaluminate cement is rapid-hardening 42.5 sulfoaluminate cement, with an average particle size of 10 µm-11 µm, and the mass of calcium oxide and alumina in the sulfoaluminate cement clinker accounts for at least 90% of the total mass of the sulfoaluminate cement.

[0012] Preferably, the average particle size of the fine quartz sand is 160 µm-200 µm.

[0013] Preferably, the water-reducing agent has a water reduction rate of 25%-30%, the thickener has a viscosity of 100,000, and the loss on drying is less than or equal to 5%.

[0014] Preferably, the fiber is ultra-high molecular weight polyethylene fiber, with a length of 4 mm-7 mm, a diameter of 20 μm-30 μm, and a density of 0.97 g / cm³. 3 -0.98 g / cm 3 The elastic modulus is greater than or equal to 120 GPa, and the fracture strength is greater than or equal to 3.1 GPa.

[0015] The preparation method of the above-mentioned high-toughness cement-polymer composite material includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 135 r / min-145 r / min for 1 min-5 min until they are evenly mixed to obtain a uniform mixture. S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solution. Slowly add the solution to the above mixture and stir at 135 r / min-145 r / min for 2 min-5 min to obtain a slurry. S3. Add the thickener to the slurry and stir at 135 r / min-145 r / min for 1 min-2 min to obtain a uniform cement mortar. S4. Add the fiber to the cement mortar and stir at 400 r / min-450 r / min for 1 min-5 min until it is evenly dispersed to obtain a uniformly mixed slurry. S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a steam curing box at 60℃-80℃ for 2-4 days to obtain hardened cement sub-sheets. S6. Assemble the cured cement sub-sheets to obtain cement sheets, apply polymer to the upper surface of the cement sheets, and assemble the upper layer of cement sheets on top of the cement sheets. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. S7. The composite material preform is cured for 10-15 hours to obtain a high-toughness cement-polymer composite material.

[0016] The advantages and positive effects of the high-toughness cement-polymer composite material and its preparation method described in this invention are as follows: This invention uses an assembly-type method to prepare the cement-polymer composite material, resulting in different angles between adjacent cement sheets. The adjacent cement sheets rotate horizontally, and this interlayer angle deflection increases the tip resistance of crack propagation and lengthens the crack propagation path, effectively improving the flexural strength and toughness of the cement-based material. Coating the adjacent cement sheets with a polymer optimizes the interlayer bonding strength, improves the overall integrity of the cement-based material, and the polymer's excellent toughness significantly enhances the bending deformation and fracture energy dissipation of the cement-based material, effectively improving its toughness.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the mold structure according to Embodiment 1 of the present invention; Figure 2 This is a physical drawing of the mold used in Embodiment 1 of the present invention; Figure 3 This is a photograph of the cement sheet from Embodiment 5 of the present invention. Figure 4 Here is a photograph of the high-toughness cement-polymer composite material obtained in an embodiment of the present invention; Figure 5 This is a schematic diagram of the mold structure of Comparative Example 5 of the present invention; Figure 6 The figures show a comparison of the three-point bending test results of the composite materials in Examples 1-5 and Comparative Examples 1-5 of this invention.

[0019] Figure Labels 1. Cement sheet; 2. Cement flake. Detailed Implementation

[0020] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] A high-toughness cement-polymer composite material includes several stacked cement sheets 2, which are bonded together by polymer. Each cement sheet 2 includes several cement sub-sheets 1, which are arranged parallel to each other and assembled into the cement sheet 2 by polymer bonding. The included angle between adjacent cement sub-sheets 1 is 10°-90°.

[0024] The cement sheet 2 has 8-15 layers and a thickness of 2mm-4mm.

[0025] The polymer is epoxy resin or polyurethane, and the thickness of the polymer is 0.7mm-1mm.

[0026] The epoxy resin is one or more of bisphenol A type epoxy resin, phenolic epoxy resin, and alicyclic epoxy resin. The polyurethane is one or more of polyester type polyurethane, polyether type polyurethane, and polycarbonate type polyurethane.

[0027] Cement flakes 2 comprise the following components in parts by weight: 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine silica sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, and 15 parts fiber. The polymer between cement flakes 2 is 10-20 parts.

[0028] The silicate cement is P·Ⅱ52.5 silicate cement, with a clinker and gypsum content of ≥95% and a limestone content of ≤5%. The sulfoaluminate cement is a rapid-hardening 42.5 sulfoaluminate cement with an average particle size of 10 µm-11 µm. The mass of calcium oxide and alumina in the sulfoaluminate cement clinker must account for at least 90% of the total mass of the sulfoaluminate cement.

[0029] Fine quartz sand is used as aggregate, and the average particle size of fine quartz sand is 160 µm-200 µm.

[0030] The water-reducing agent is PCA-Ⅰ series polycarboxylate high-performance water-reducing agent produced by Jiangsu Subote New Material Co., Ltd., with a water reduction rate of 25%-30%. The thickener is hydroxypropyl methylcellulose produced by Tianjin Huasheng Chemical Reagent Co., Ltd., with a viscosity of 100,000 and a drying loss of less than or equal to 5%.

[0031] The admixture system of this invention uses a combination of hydroxypropyl methylcellulose and polycarboxylate superplasticizer, which can achieve synergistic control of fluidity and water retention during the formwork casting process, effectively avoiding segregation, bleeding and shrinkage cracks, thereby improving the molding quality and durability of the cast components.

[0032] The fiber is ultra-high molecular weight polyethylene fiber, with a length of 4 mm-7 mm, preferably 6 mm; a diameter of 20 μm-30 μm, preferably 25 μm; and a density of 0.97 g / cm³. 3 -0.98 g / cm 3 The elastic modulus is greater than or equal to 120 GPa, and the fracture strength is greater than or equal to 3.1 GPa.

[0033] The preparation method of the above-mentioned high-toughness cement-polymer composite material includes the following steps: S1. Weigh silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 135 r / min-145 r / min for 1 min-5 min until they are evenly mixed to obtain a uniform mixture.

[0034] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 135 r / min-145 r / min for 2 min-5 min to obtain a slurry.

[0035] S3. Add the thickener to the slurry and stir at 135 r / min-145 r / min for 1 min-2 min to obtain a uniform cement mortar.

[0036] S4. Add the fiber to the cement mortar and stir at 400 r / min-450 r / min for 1 min-5 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0037] S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a steam curing box at 60℃-80℃ for 2-4 days to obtain hardened cement sub-slabs 1.

[0038] S6. Assemble the cured cement sub-slabs 1 to obtain cement sheet 2. Apply polymer to the upper surface of cement sheet 2 and assemble the upper layer of cement sheet 2 on top of cement sheet 2. Repeat the assembly until the set number of layers is reached to obtain the composite material blank.

[0039] S7. The composite material preform is cured for 10-15 hours to obtain a high-toughness cement-polymer composite material. A physical image of the high-toughness cement-polymer composite material is shown below. Figure 4 As shown.

[0040] Example 1 The high-toughness cement-polymer composite material comprises, by weight, 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, 20 parts polyurethane, and 15 parts fiber.

[0041] The silicate cement is P·Ⅱ52.5 silicate cement, with a clinker and gypsum content of ≥95% and a limestone content of ≤5%. The sulfoaluminate cement is a rapid-hardening 42.5 sulfoaluminate cement with an average particle size of 10 µm-11 µm. The mass of calcium oxide and alumina in the sulfoaluminate cement clinker must account for at least 90% of the total mass of the sulfoaluminate cement.

[0042] The average particle size of fine quartz sand is 160 µm-200 µm.

[0043] The water-reducing agent is PCA-Ⅰ series polycarboxylate high-performance water-reducing agent produced by Jiangsu Subote New Material Co., Ltd., with a water reduction rate of 25%-30%. The thickener is hydroxypropyl methylcellulose produced by Tianjin Huasheng Chemical Reagent Co., Ltd., with a viscosity of 100,000 and a drying loss of less than or equal to 5%.

[0044] The fiber is ultra-high molecular weight polyethylene fiber, with a length of 6 mm and a diameter of 25 μm; density 0.97 g / cm³. 3 -0.98g / cm 3 The elastic modulus is greater than or equal to 120 GPa, and the fracture strength is greater than or equal to 3.1 GPa.

[0045] The polyurethane used is a two-component polyether polyurethane (component ratio 1:1).

[0046] A method for preparing high-toughness cement-polymer composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0047] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0048] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0049] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0050] S5. Pour the uniformly mixed slurry into a mold for molding, and cure it in a 70℃ steam curing chamber for 3 days to obtain hardened cement sub-slab 1. The structure and actual object of the mold are as follows: Figure 1 , Figure 2 As shown, multiple layers of cement sheets 2 and cement sub-sheets 1 can be cast simultaneously using a single mold. The width of cement sub-sheet 1 is 20mm.

[0051] S6. Assemble the cured cement sheet 1 to obtain cement sheet 2. Apply polyurethane to the upper surface of cement sheet 2, and assemble the next layer of cement sheet 2 on top of cement sheet 2. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. The angle between adjacent cement sheets 2 is 30°, and the number of stacked layers is 8.

[0052] During assembly, the bottom layer of cement sub-sheets 1 are first assembled to form the bottom layer of cement sheet 2. Then, polyurethane is coated onto the upper surface of the bottom layer of cement sheet 2, and the second layer of cement sub-sheets 1 is assembled on top of the bottom layer of cement sheet 2 and coated with polyurethane. This process is repeated until the entire composite material is assembled. During the polyurethane coating process, it penetrates between adjacent cement sub-sheets 1, achieving connection between the cement sub-sheets 1 on the same layer of cement sheet 2.

[0053] S7. The composite material preform is cured for 12 hours to obtain a high-toughness cement-polymer composite material.

[0054] Example 2 The high-toughness cement-polymer composite material comprises, by weight, 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, 15 parts polyurethane, and 15 parts fiber.

[0055] In this embodiment, the silicate cement, sulfoaluminate cement, silica fume, fly ash, fine quartz sand, water, water-reducing agent, thickener, and fiber are the same products as in Example 1.

[0056] The polyurethane used is a two-component polyether polyurethane (component ratio 1:1).

[0057] A method for preparing high-toughness cement-polymer composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0058] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0059] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0060] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0061] S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a 70℃ steam curing box for 3 days to obtain hardened cement sub-slab 1.

[0062] S6. Assemble the cured cement sheet 1 to obtain cement sheet 2. Apply polyurethane to the upper surface of cement sheet 2, and assemble the next layer of cement sheet 2 on top of cement sheet 2. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. The angle between adjacent cement sheets 2 is 30°, and the number of stacked layers is 10.

[0063] S7. The composite material preform is cured for 12 hours to obtain a high-toughness cement-polymer composite material.

[0064] Example 3 The high-toughness cement-polymer composite material comprises, by weight, 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, 10 parts polyurethane, and 15 parts fiber.

[0065] In this embodiment, the silicate cement, sulfoaluminate cement, silica fume, fly ash, fine quartz sand, water, water-reducing agent, thickener, and fiber are the same products as in Example 1.

[0066] The polyurethane used is a two-component polyether polyurethane (component ratio 1:1).

[0067] A method for preparing high-toughness cement-polymer composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0068] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0069] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0070] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0071] S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a 70℃ steam curing box for 3 days to obtain hardened cement sub-slab 1.

[0072] S6. Assemble the cured cement sheet 1 to obtain cement sheet 2. Apply polyurethane to the upper surface of cement sheet 2, and assemble the next layer of cement sheet 2 on top of cement sheet 2. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. The angle between adjacent cement sheets 2 is 30°, and the number of stacked layers is 15.

[0073] S7. The composite material preform is cured for 12 hours to obtain a high-toughness cement-polymer composite material.

[0074] Example 4 The high-toughness cement-polymer composite material comprises, by weight, 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, 20 parts epoxy resin, and 15 parts fiber.

[0075] In this embodiment, the silicate cement, sulfoaluminate cement, silica fume, fly ash, fine quartz sand, water, water-reducing agent, thickener, and fiber are the same products as in Example 1.

[0076] The epoxy resin is a mixture of bisphenol A type epoxy resin and polyamide (ratio 1:1).

[0077] A method for preparing high-toughness cement-polymer composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0078] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0079] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0080] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0081] S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a 70℃ steam curing box for 3 days to obtain hardened cement sub-slab 1.

[0082] S6. Assemble the cured cement sheet 1 to obtain cement sheet 2. Apply epoxy resin to the upper surface of cement sheet 2, and assemble the next layer of cement sheet 2 on top of cement sheet 2. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. The angle between adjacent cement sheets 2 is 30°, and the number of stacked layers is 8.

[0083] S7. The composite material preform is cured for 12 hours to obtain a high-toughness cement-polymer composite material.

[0084] Example 5 The high-toughness cement-polymer composite material comprises, by weight, 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, 20 parts epoxy resin, and 15 parts fiber.

[0085] In this embodiment, the silicate cement, sulfoaluminate cement, silica fume, fly ash, fine quartz sand, water, water-reducing agent, thickener, and fiber are the same products as in Example 1.

[0086] The epoxy resin is a mixture of bisphenol A type epoxy resin and polyamide (ratio 1:1).

[0087] A method for preparing high-toughness cement-polymer composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0088] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0089] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0090] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0091] S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a 70℃ steam curing box for 3 days to obtain hardened cement sub-slab 1.

[0092] S6. Assemble the cured cement sheet 1 to obtain cement sheet 2. Apply epoxy resin to the upper surface of cement sheet 2, and assemble the next layer of cement sheet 2 on top of cement sheet 2. Repeat this assembly process until the set number of layers is reached to obtain the composite material preform. The angle between adjacent cement sheets 2 is 45°, and the stacking number is 8 layers. The assembled cement sheet 1 is shown in the figure. Figure 3 As shown.

[0093] S7. The composite material preform is cured for 12 hours to obtain a high-toughness cement-polymer composite material.

[0094] Comparative Example 1 The difference between this comparative example composite material and Example 1 is that this example is directly cast into a composite material.

[0095] The raw materials for this comparative example composite material are as follows (by weight): 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, and 0.4 parts thickener.

[0096] The method for preparing composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0097] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0098] S3. Add the thickener to the slurry, stir at 140 r / min for 1 min, and then stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniform cement mortar.

[0099] S4. Pour the uniformly mixed slurry into the mold for molding, demold after curing for 1 day, and cure in a 70℃ steam curing chamber for 3 days to obtain the composite material.

[0100] Comparative Example 2 The only difference between this comparative example and Example 1 is that the angle between adjacent cement sheets 2 in this comparative example is 0°; all other aspects are consistent with Example 1.

[0101] Comparative Example 3 The only difference between this comparative example and Example 5 is that the angle between adjacent cement sheets 2 in this comparative example is 0°; all other aspects are the same as in Example 5.

[0102] Comparative Example 4 The difference between this comparative example and Example 1 is that no polymer was applied between the layers.

[0103] The comparative example composite material, by mass, includes: 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, and 15 parts fiber.

[0104] The method for preparing composite materials includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 140 r / min for 2 min until they are evenly mixed to obtain a uniform mixture.

[0105] S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 140 r / min for 3 min to obtain a slurry.

[0106] S3. Add the thickener to the slurry and stir at 140 r / min for 1 min to obtain a uniform cement mortar.

[0107] S4. Add the fiber to the cement mortar and stir at 420 r / min for 2 min until it is evenly dispersed to obtain a uniformly mixed slurry.

[0108] S5. Pour the uniformly mixed slurry into the mold for molding and let it stand for 5 minutes.

[0109] S6. After standing for 5 minutes, take the cement sub-piece 1 out of the mold, stack it at an angle of 30° with 8 layers, and cure it in a 70° steam curing box for 3 days to obtain the composite material.

[0110] Comparative Example 5 The difference between this comparative example and Example 1 is that: the cement sub-sheets 1 are not set at an angle, but are stacked in an alternating manner to 8 layers, and the mold is as follows. Figure 5 As shown; the rest are consistent with Example 1.

[0111] Performance testing: The flexural strength of the cement-based composite materials of Examples 1-5 and Comparative Examples 1-5 was tested, and the fracture energy was calculated.

[0112] Test method: Flexural strength testing was conducted according to the provisions of GB / T17671-2021 "Test Method for Strength of Cement Mortar". A 40×40×160 mm mold was used to prepare the mortar. 3The specimen was placed on the support cylinder of the testing machine, with the major axis of the specimen perpendicular to the support cylinder. A uniform load was applied vertically to the top surface of the prism through a loading cylinder at a loading rate of 0.05 mm / min until complete fracture, thus obtaining the flexural strength. R f and the load-displacement curve. The load-displacement curve is as follows: Figure 6 As shown.

[0113] Flexural strength is calculated using equation (1): (1) In the formula, R f Flexural strength (MPa); F f The load (N) applied to the middle of the prism when it breaks; L The distance between the supporting cylinders (mm); b is the side length (mm) of the square cross-section of the prism.

[0114] The fracture energy is determined by the area under the entire load-displacement curve and is calculated by equation (2): (2) In the formula, W F The area under the load-displacement curve; W The width of the sample (mm); D The height of the sample is in mm.

[0115] The results are shown in Table 1.

[0116] Table 1 Test Results

[0117] As can be seen from the results in Table 1 above, a comparison of the experimental results of Comparative Example 1 and Examples 1-3 shows that only an appropriate ratio of cement to polymer content can achieve the synergistic development of flexural strength and fracture energy of the specimen. Too much or too little will not achieve a similar effect. In Example 3, due to the low interlayer polymer content, the specimen has poor integrity and cannot achieve a significant toughening effect.

[0118] The experimental results of Comparative Examples 2 and 3 with those of Examples 1, 4, and 5 show that angle deflection can significantly improve the flexural strength and fracture energy of the specimens. The main mechanism is that the interlaminar angle deflection increases the tip resistance of crack propagation, thereby improving the flexural strength of the specimens. On the other hand, the interlaminar angle deflection induces the extension of the crack propagation path, which increases the energy consumption during the fracture process of the specimens.

[0119] Comparison of the experimental results of Comparative Example 4 with those of Examples 1 and 5 shows that interlayer polymers can improve the flexural strength and fracture energy of the specimens. On the one hand, interlayer polymers optimize the interlayer bonding strength of the specimens and improve the overall integrity of the specimens. On the other hand, interlayer polymers have good toughness, which significantly improves the bending deformation and fracture energy consumption of the specimens.

[0120] Therefore, the high-toughness cement-polymer composite material and its preparation method described in this invention can solve the problem of poor toughness in existing cement-based materials.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-toughness cement-polymer composite material, characterized in that: It comprises several stacked cement sheets, which are bonded together by polymer. Each cement sheet includes several cement sub-sheets, and the included angle between the cement sub-sheets of adjacent cement sheets is 10°-90°.

2. The high-toughness cement-polymer composite material according to claim 1, characterized in that: The cement sheet has 8-15 layers and a thickness of 2mm-4mm.

3. The high-toughness cement-polymer composite material according to claim 1, characterized in that: The polymer is epoxy resin or polyurethane, and the thickness of the polymer is 0.7mm-1mm.

4. The high-toughness cement-polymer composite material according to claim 1, characterized in that: The epoxy resin is one or more of bisphenol A type epoxy resin, phenolic epoxy resin, and alicyclic epoxy resin; the polyurethane is one or more of polyester type polyurethane, polyether type polyurethane, and polycarbonate type polyurethane.

5. The high-toughness cement-polymer composite material according to claim 1, characterized in that, The cement flakes comprise the following components in parts by weight: 456 parts silicate cement, 60 parts sulfoaluminate cement, 108 parts silica fume, 576 parts fly ash, 312 parts fine quartz sand, 312 parts water, 1 part water-reducing agent, 0.4 parts thickener, and 15 parts fiber; the polymer between the cement flakes is 10-20 parts.

6. The high-toughness cement-polymer composite material according to claim 5, characterized in that: The silicate cement is P·Ⅱ52.5 silicate cement, with cement clinker and gypsum content greater than or equal to 95% and limestone content less than or equal to 5%; the sulfoaluminate cement is rapid-hardening 42.5 sulfoaluminate cement, with an average particle size of 10 µm-11 µm, and the mass of calcium oxide and alumina in the sulfoaluminate cement clinker accounts for at least 90% of the total mass of the sulfoaluminate cement.

7. The high-toughness cement-polymer composite material according to claim 5, characterized in that: The average particle size of the fine quartz sand is 160 µm-200 µm.

8. The high-toughness cement-polymer composite material according to claim 5, characterized in that: The water-reducing agent has a water reduction rate of 25%-30%, the thickener has a viscosity of 100,000, and a drying loss of less than or equal to 5%.

9. A high-toughness cement-polymer composite material according to claim 5, characterized in that: The fiber is ultra-high molecular weight polyethylene fiber, with a length of 4 mm-7 mm, a diameter of 20 μm-30 μm, and a density of 0.97 g / cm³. 3 -0.98 g / cm 3 The elastic modulus is greater than or equal to 120 GPa, and the fracture strength is greater than or equal to 3.1 GPa.

10. A method for preparing a high-toughness cement-polymer composite material according to any one of claims 5-9, characterized in that, Includes the following steps: S1. Weigh out silicate cement, sulfoaluminate cement, silica fume, fly ash and fine quartz sand according to the mass ratio, and stir them at 135 r / min-145 r / min for 1 min-5 min until they are evenly mixed to obtain a uniform mixture. S2. Add the water-reducing agent to water and stir to obtain a uniform water-soluble solvent. Slowly add the solvent to the above mixture and stir at 135 r / min-145 r / min for 2 min-5 min to obtain a slurry. S3. Add the thickener to the slurry and stir at 135 r / min-145 r / min for 1 min-2 min to obtain a uniform cement mortar. S4. Add the fiber to the cement mortar and stir at 400 r / min-450 r / min for 1 min-5 min until it is evenly dispersed to obtain a uniformly mixed slurry. S5. Pour the uniformly mixed slurry into the mold for molding, and cure it in a steam curing box at 60℃-80℃ for 2-4 days to obtain hardened cement sub-sheets. S6. Assemble the cured cement sub-sheets to obtain cement sheets, apply polymer to the upper surface of the cement sheets, and assemble the upper layer of cement sheets on top of the cement sheets. Repeat the assembly process until the set number of layers is reached to obtain a composite material blank. S7. The composite material preform is cured for 10-15 hours to obtain a high-toughness cement-polymer composite material.

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