Polyethylene reinforced high-toughness cement-based composite material and preparation method and application thereof

Abstract

The application belongs to the technical field of traffic engineering materials, and particularly relates to a polyethylene reinforced high-toughness cement-based composite material and a preparation method and application thereof. The cement-based composite material is composed of the following components in parts by weight: cement 600-700 parts, quartz sand 700-900 parts, fly ash 280-380 parts, silica fume 80-120 parts, sinking beads 80-120 parts, CSA expanding agent 45-55 parts, high-performance polycarboxylic acid water reducer 5-8 parts, notched polyethylene fiber 5-8 parts, ultrahigh molecular weight polyethylene fiber 10-15 parts and water 320-390 parts. The composite material prepared by the application has good fluidity, can reduce construction difficulty, improve construction efficiency, and meets the performance requirements of the steel-concrete composite beam bridge deck continuous section.

Description

Technical Field

[0001] This invention belongs to the field of transportation engineering materials technology, specifically relating to a polyethylene-reinforced high-toughness cement-based composite material, its preparation method, and its application. Background Technology

[0002] The continuous deck section of a steel-concrete composite beam bridge is a critical load-bearing component. This section is subjected to cyclic vehicle loads and bearing rotational deformation constraints over a long period, continuously operating under negative bending moment conditions, making it highly susceptible to tensile cracking. Existing projects often use high-grade self-compacting cement concrete to pour this section. While the material has sufficient compressive strength, its inherent toughness is poor, making it prone to cracking and unable to meet the long-term service durability requirements.

[0003] To address this technical challenge, the engineering field has successively introduced two new types of cement-based materials: ultra-high performance concrete (UHPC) and polyvinyl alcohol fiber-reinforced high-toughness cement-based composites (PVA-ECC). However, these materials still struggle to meet the complex service conditions of continuous bridge deck sections. UHPC is made from silicate cement, silica fume, ultrafine mineral admixtures, quartz sand, steel fibers, and high-efficiency water-reducing agents. After removing coarse aggregates, its matrix structure is dense, exhibiting superior compressive strength, impermeability, and frost resistance, effectively enhancing structural load-bearing capacity. However, this material exhibits significant brittleness, with an ultimate tensile strain of only 0.1% to 0.3%. Despite high initial crack strength, once cracks appear, they propagate rapidly, failing to form a fine and controllable microcrack system. Its toughness and deformation adaptability do not meet usage standards. Furthermore, the internal steel fibers are prone to corrosion in the humid environment of the bridge deck, and the resulting rust expansion stress continuously damages the matrix structure, compromising long-term service durability.

[0004] Polyvinyl alcohol fiber-reinforced high-toughness cementitious composite (PVA-ECC) uses cement, fly ash, and quartz sand as the matrix, with randomly incorporated short-cut PVA fibers. Its coarse aggregate-free structure allows for an ultimate tensile strain of 3%–5%, exhibiting strain hardening characteristics under tension and forming a multi-crack pattern. It demonstrates excellent deformation and crack resistance, meeting the deformation requirements of continuous bridge decks subjected to repeated rotation and minor slippage. However, PVA fibers have poor alkali and high-temperature resistance, and are prone to aging and degradation under sunlight and high-temperature environments, as well as in the alkaline media of cement hydration, leading to a significant decrease in the material's ductility and mechanical properties. Furthermore, the material has a relatively low elastic modulus and insufficient structural stiffness, resulting in excessive vertical deformation of continuous bridge deck sections under heavy traffic loads, which reduces driving comfort. Summary of the Invention

[0005] The purpose of this invention is to provide a polyethylene-reinforced high-toughness cement-based composite material, its preparation method and application, thereby overcoming the shortcomings of the prior art, while taking into account multiple technical indicators such as toughness deformation, long-term durability, and structural stiffness, and being able to meet the special stress and service scenarios of the continuous section of the steel-concrete composite beam bridge deck.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a polyethylene-reinforced high-toughness cement-based composite material, which, by weight, comprises the following components: 600-700 parts cement, 700-900 parts quartz sand, 280-380 parts fly ash, 80-120 parts silica fume, 80-120 parts precipitated beads, 45-55 parts CSA expanding agent, 5-8 parts high-performance polycarboxylate superplasticizer, 5-8 parts notched polyethylene fiber, 10-15 parts ultra-high molecular weight polyethylene fiber, and 320-390 parts water.

[0007] Secondly, the present invention provides a method for preparing polyethylene-reinforced high-toughness cement-based composite materials, comprising the following steps: S1. Mix quartz sand, cement, fly ash, silica fume, sedimentary beads, and CSA expansion agent evenly to obtain dry material; S2. Add polycarboxylate superplasticizer to water to make polycarboxylate superplasticizer solution, add polycarboxylate superplasticizer solution to dry material and continue to stir and mix to obtain cement mortar; S3. Add ultra-high molecular weight polyethylene fiber and notched polyethylene fiber to cement mortar in batches and continue to stir and mix to obtain a mixture. S4. Pour the mixture into the mold, and then vibrate and cure it to obtain the final product.

[0008] The preparation method first involves pre-mixing various powder raw materials evenly to ensure a uniform and stable distribution of the matrix components. Then, the fluidity of the slurry is precisely controlled by the water-reducing agent aqueous solution, which effectively improves the mixing uniformity and workability of the cement slurry. Finally, two types of functional polyethylene fibers are added in batches and stirred thoroughly, which can effectively avoid fiber agglomeration and clumping, ensuring that the fibers are evenly dispersed and randomly distributed in the matrix, maximizing the synergistic effect of fiber toughening and crack resistance.

[0009] Thirdly, the present invention provides the application of polyethylene-reinforced high-toughness cement-based composite materials in the continuous sections of the bridge deck of steel-concrete composite beam bridges.

[0010] Fourthly, the present invention provides a method for connecting the deck of a steel-concrete composite beam bridge, wherein a polyethylene-reinforced high-toughness cement-based composite material is cast at the connection point of the steel-concrete composite beam bridge deck.

[0011] The beneficial effects of this invention are: (1) The polyethylene-reinforced high-toughness cement-based composite material of the present invention uses cement and quartz sand as basic skeleton components to provide stable matrix strength and structural stiffness for the material, effectively solving the problems of insufficient stiffness and excessive vertical deformation under heavy load of traditional high-toughness cement-based materials, and ensuring the smoothness of bridge deck driving; the compound addition of fly ash, silica fume and sediment can effectively optimize the particle size distribution of the matrix, fill the internal pores, improve the matrix density and impermeability durability, and at the same time improve the workability of the slurry, making it suitable for the fine casting construction of continuous bridge deck sections; the CSA expansion agent can compensate for the hydration shrinkage of the cement matrix, inhibit the shrinkage cracking defects during material curing and long-term service, and reduce the source of cracking. Microcracks appear in continuous sections of the bridge deck; high-performance polycarboxylate superplasticizer can ensure the fluidity and workability of the slurry under low water-binder ratio conditions, while taking into account both material density and ease of construction; the compounding of notched polyethylene fiber and ultra-high molecular weight polyethylene fiber forms a multi-level fiber toughening system. The two fibers work synergistically, which can not only give the material excellent strain hardening ability and multi-crack characteristics by relying on high elongation, but also significantly improve the tensile toughness and deformation resistance of the matrix, adapting to the stress and deformation characteristics of repeated rotation and slight slippage of continuous sections of the bridge deck, but also avoid the defects of poor alkali resistance and high temperature resistance and easy aging failure of single PVA fiber, greatly improving the long-term mechanical stability and crack resistance of the material.

[0012] (2) The preparation method of the present invention is simple to operate and has high molding efficiency. It does not require complex equipment and special process conditions. Vibration molding and conventional curing methods are suitable for engineering site construction scenarios, and can realize large-scale batch preparation. The process is stable and practical, effectively ensuring the uniformity of mechanical properties and structural stability of the finished composite material.

[0013] (3) The polyethylene-reinforced high-toughness cement-based composite material prepared by the present invention has comprehensive properties of high stiffness, high toughness, low shrinkage and high durability, which fully meets the stringent service requirements of the continuous section of the steel-concrete composite beam bridge deck. Specifically, it meets the following performance indicators: compressive strength ≥55Mpa, flexural strength ≥10Mpa, elastic modulus ≥20Gpa; initial crack tensile strength ≥3Mpa, ultimate tensile strain ≥1.5%, which can meet the crack resistance requirements under negative bending moment and improve durability. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0015] Figure 1 The dimensions of the "dog bone" specimen in Embodiment 1 of this invention; Figure 2 These are specimens of various sizes in Embodiment 1 of the present invention; Figure 3 The tensile test in Embodiment 1 of the present invention; Figure 4 The specimen developed cracks after the tensile test in Embodiment 1 of the present invention. Detailed Implementation

[0016] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components not specified by manufacturer are all commercially available conventional products. Specifically, the cement is P·O42.5 ordinary Portland cement, the fly ash is grade II or higher fly ash, the silica fume is SF94 silica fume, the granules are semi-dense type, the quartz sand has a particle size of 80-120 mesh, the CSA expanding agent contains ≤5wt% magnesium oxide and ≤0.75wt% alkali, and the parameters of the notched polyethylene fiber are: length 16mm, tensile strength 800-1000MPa; tensile strength of ultra-high molecular weight polyethylene fiber ≥3000MPa; and equivalent flexural strength 9-14N / mm². 2 .

[0017] In a first aspect, the present invention provides a polyethylene-reinforced high-toughness cement-based composite material, which, by weight, comprises the following components: 600-700 parts cement, 700-900 parts quartz sand, 280-380 parts fly ash, 80-120 parts silica fume, 80-120 parts precipitated beads, 45-55 parts CSA expanding agent, 5-8 parts high-performance polycarboxylate superplasticizer, 5-8 parts notched polyethylene fiber, 10-15 parts ultra-high molecular weight polyethylene fiber, and 320-390 parts water.

[0018] Polyethylene fiber is a typical hydrophobic and inert polymer material with extremely low surface water absorption. It does not absorb free water during the mixing process, which can improve the flowability of the fiber, reduce fiber clumping and sedimentation, improve the uniformity of mixing, reduce the difficulty of construction, and has good workability.

[0019] Ultra-high molecular weight polyethylene (UHMWPE) fibers possess ultra-high tensile strength and ultimate elongation, with a tensile strength ≥3000 MPa. They are high-toughness, high-strength, and flexible fibers. This allows the composite material to develop multiple cracks without failure during stress, extending the service life of the structure. Scoring polyethylene fibers, through surface scoring and chemical surface treatment, can effectively improve the initial crack strength and overall stiffness of the composite material. In the early stages of tensile stress on the matrix, the scoring fibers, relying on strong interfacial bonding, can quickly distribute internal tensile stress, inhibit the initiation of microcracks, significantly improve the initial crack strength of the material, and compensate for the insufficient stiffness of UHMWPE fibers.

[0020] The blending of two types of polyethylene fibers achieves a synergistic balance between stiffness and toughness in the composite material. The notched polyethylene fiber enhances the early-stage stiffness, initial crack strength, and compressive strength of the matrix, controlling the mechanical properties of the material before cracking. The ultra-high molecular weight polyethylene fiber enhances the post-cracking ductility, residual strength, and energy dissipation capacity, controlling the deformation properties of the material after cracking. This allows the composite material to possess both high rigidity and high toughness, meeting the combined stiffness and flexibility requirements of the continuous negative bending moment zone of the bridge deck.

[0021] In some other embodiments, the polyethylene-reinforced high-toughness cement-based composite material is composed of the following components by weight: 600-700 parts cement, 700-900 parts quartz sand, 280-380 parts fly ash, 100 parts silica fume, 100 parts precipitated beads, 50 parts CSA expanding agent, 6 parts high-performance polycarboxylate superplasticizer, 6 parts notched polyethylene fiber, 12 parts ultra-high molecular weight polyethylene fiber, and 320-390 parts water.

[0022] In some other embodiments, the cement is P·O42.5 ordinary Portland cement, the beads are semi-dense type, and the bulk density of the beads is 800-1000 kg / m³. 3 .

[0023] In some other embodiments, the particle size of the quartz sand is 80-120 mesh, and the magnesium oxide content and alkali content in the CSA expanding agent are ≤5wt% and ≤0.75wt%, respectively.

[0024] In other embodiments, the parameters of the notched polyethylene fiber are: length 16 mm, tensile strength 800-1000 MPa; tensile strength of ultra-high molecular weight polyethylene fiber ≥3000 MPa; and equivalent flexural strength 9-14 N / mm². 2 .

[0025] In other embodiments, the polyethylene-reinforced high-toughness cementitious composite material has a compressive strength ≥55 MPa, a flexural strength ≥10 MPa, an elastic modulus ≥20 GPa, an initial crack tensile strength ≥3 MPa, and an ultimate tensile strain ≥1.5%.

[0026] Secondly, the present invention provides a method for preparing polyethylene-reinforced high-toughness cement-based composite materials, comprising the following steps: S1. Mix quartz sand, cement, fly ash, silica fume, sedimentary beads, and CSA expansion agent evenly to obtain dry material; S2. Add polycarboxylate superplasticizer to water to make polycarboxylate superplasticizer solution, add polycarboxylate superplasticizer solution to dry material and continue to stir and mix to obtain cement mortar; S3. Add ultra-high molecular weight polyethylene fiber and notched polyethylene fiber to cement mortar in batches and continue to stir and mix to obtain a mixture. S4. Pour the mixture into the mold, and then vibrate and cure it to obtain the final product.

[0027] In some other embodiments, in steps S1-S3, the stirring time is 20-40s, 90-120s and 120-150s respectively, and the stirring speed is 55-60r / min.

[0028] In some other embodiments, in step S4, the vibration molding time is 60-80 seconds, the curing time is 28 days, the curing humidity is above 95%, and the temperature is 20±2℃.

[0029] Thirdly, the present invention provides the application of polyethylene-reinforced high-toughness cement-based composite materials in the continuous sections of the bridge deck of steel-concrete composite beam bridges.

[0030] Fourthly, the present invention provides a method for connecting the deck of a steel-concrete composite beam bridge, wherein a polyethylene-reinforced high-toughness cement-based composite material is cast at the connection point of the steel-concrete composite beam bridge deck.

[0031] Example 1 A polyethylene-reinforced high-toughness cement-based composite material for continuous sections of the bridge deck of a steel-concrete composite beam bridge, comprising the following components by weight: 600 parts of P·O42.5 ordinary Portland cement, 900 parts of quartz sand, 280 parts of fly ash, 100 parts of silica fume, 100 parts of saturated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 6 parts of notched polyethylene fiber, 12 parts of ultra-high molecular weight polyethylene fiber, and 324 parts of water.

[0032] A method for preparing polyethylene-reinforced high-toughness cement-based composite materials includes the following steps: 1. Add quartz sand, cementitious materials (P·O42.5 ordinary Portland cement, fly ash, silica fume and sediment), and CSA expansion agent to a horizontal shaft mixer in the specified proportions, and mix for 30 seconds to obtain dry material; 2. Pour the polycarboxylate superplasticizer into water and stir evenly with a glass rod. Continue to start the mixer and slowly pour in the polycarboxylate superplasticizer solution while stirring. After all the polycarboxylate superplasticizer solution has been poured into the mixer, continue stirring for more than 90 seconds to obtain a uniform and smooth cement slurry. 3. Continue to start the mixer and slowly add the ultra-high molecular weight polyethylene fiber and the notched polyethylene fiber to the cement slurry in batches. Continue to stir for more than 120 seconds until there are no obvious fiber clumps in the mixer and all components are mixed evenly to obtain the mixture. 4. Pour the mixture from the mixer into the prepared mold, then move the mold to a vibrating table and vibrate for 60 seconds to form the final product. Following the specifications, cure the polyethylene-reinforced cementitious composite material for 28 days before taking it out for testing.

[0033] Example 2 Unlike Example 1, the polyethylene-reinforced high-toughness cement-based composite material is composed of the following components by weight: 700 parts of P·O42.5 ordinary silicate cement, 700 parts of quartz sand, 380 parts of fly ash, 100 parts of silica fume, 100 parts of precipitated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 6 parts of notched polyethylene fiber, 12 parts of ultra-high molecular weight polyethylene fiber, and 384 parts of water.

[0034] The preparation method is the same as in Example 1.

[0035] Example 3 Unlike Example 1, the polyethylene-reinforced high-toughness cement-based composite material is composed of the following components by weight: 600 parts of P·O42.5 ordinary silicate cement, 800 parts of quartz sand, 380 parts of fly ash, 100 parts of silica fume, 100 parts of precipitated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 6 parts of notched polyethylene fiber, 12 parts of ultra-high molecular weight polyethylene fiber, and 354 parts of water.

[0036] The preparation method is the same as in Example 1.

[0037] Comparative Example 1 Unlike Example 1, the polyethylene-reinforced high-toughness cement-based composite material, as shown in Table 1, consists of the following components by weight: 600 parts of P·O42.5 ordinary Portland cement, 900 parts of quartz sand, 280 parts of fly ash, 100 parts of silica fume, 100 parts of precipitated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 16 parts of ultra-high molecular weight polyethylene fiber, and 324 parts of water.

[0038] The specimen preparation method is the same as in Example 1.

[0039] Comparative Example 2 Unlike Example 1, the composition of the polyethylene-reinforced high-toughness cement-based composite material is shown in Table 1. In addition to the addition of ultra-high molecular weight polyethylene fibers, some steel fibers are added to improve the initial crack strength of the mixture. By weight, it specifically consists of the following components: 600 parts of P·O42.5 ordinary Portland cement, 900 parts of quartz sand, 280 parts of fly ash, 100 parts of silica fume, 100 parts of precipitated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 12 parts of ultra-high molecular weight polyethylene fiber, 50 parts of copper-plated microfilament hook-shaped steel fiber (tensile strength ≥2000 MPa), and 324 parts of water.

[0040] The specimen preparation method is the same as in Example 1.

[0041] Comparative Example 3 Unlike Example 1, the composition of the polyethylene-reinforced high-toughness cementitious composite material is shown in Table 1. In addition to the polyethylene fiber blend, some steel fibers are added to improve the initial crack strength of the mixture. By weight, it specifically consists of the following components: 600 parts P·O42.5 ordinary Portland cement, 900 parts quartz sand, 280 parts fly ash, 100 parts silica fume, 100 parts granules, 50 parts CSA expansion agent, 6 parts high-performance polycarboxylate superplasticizer, 6 parts notched polyethylene fiber, 12 parts ultra-high molecular weight polyethylene fiber, 10 parts steel fiber, and 324 parts water.

[0042] Comparative Example 4 Unlike Example 1, the composition of the high-toughness cement-based composite material is shown in Table 1, with polyvinyl alcohol fiber and steel fiber blended instead of polyethylene fiber. By weight, it consists of the following components: 600 parts P·O42.5 ordinary Portland cement, 900 parts quartz sand, 280 parts fly ash, 100 parts silica fume, 100 parts precipitated beads, 50 parts CSA expanding agent, 6 parts high-performance polycarboxylate superplasticizer, and Japanese-made polyvinyl alcohol fiber (tensile strength ≥1500 MPa, density 1.3 g / cm³). 3 18 parts, 50 parts steel fiber and 324 parts water.

[0043] The specimen preparation method is the same as in Example 1.

[0044] Comparative Example 5 Unlike Example 1, the composition of the high-toughness cement-based composite material is shown in Table 1. Polyvinyl alcohol fibers and steel fibers are mixed to replace polyethylene fibers, and the mortar-to-bond ratio is increased. By weight, it consists of the following components: 700 parts of P·O42.5 ordinary Portland cement, 700 parts of quartz sand, 380 parts of fly ash, 100 parts of silica fume, 100 parts of precipitated beads, 50 parts of CSA expansion agent, 6 parts of high-performance polycarboxylate superplasticizer, 18 parts of Japanese-made polyvinyl alcohol fibers, 50 parts of steel fibers, and 384 parts of water.

[0045] The specimen preparation method is the same as in Example 1.

[0046] Table 1 Raw Material Composition

[0047] Performance testing According to "JC / T_2461-2018 Test Methods for Mechanical Properties of High-Ductility Fiber-Reinforced Cementitious Composite Materials", specimens with different mix proportions were tested as follows: Figure 1 and Figure 2 Tensile tests were conducted on specimens with different mix proportions as shown (e.g.) Figure 3As shown in the figure, the micro-variable measuring instrument used is an extensometer with a measurement accuracy of ±0.001 mm and a loading speed of 0.5 mm / min. Since the test results of Comparative Examples 1-5 in the tensile test were unsatisfactory, the mechanical properties of Comparative Examples 1-5 were no longer tested.

[0048] According to relevant standards, the cubic compressive strength (test method JC / T 2461 5.2), flexural strength (test method JC / T 2461 8.2), and elastic modulus (test method JC / T 2461 7.2) of the mixtures of Examples 1, 2, and 3 were verified, and the experimental results are shown in Table 2.

[0049] Table 2 Performance Test Results

[0050] According to the test results of Examples 1, 2, and 3 in Table 2, under the same fiber type and dosage, the initial tensile strength of the mixture decreases with decreasing mortar ratio, while the ultimate tensile strain increases with decreasing mortar ratio. This is because the strength of the mixture matrix decreases with decreasing mortar ratio. When the first crack appears, the fibers play almost no role, and the strength is only related to the matrix itself. After the crack appears, the fibers begin to take on the tensile stress in place of the matrix, while the tensile strength of the matrix in the surrounding uncracked areas is less than the tensile stress, leading to the formation of new cracks and dense fine cracks. Macroscopically, this manifests as an increase in the ultimate tensile strain of the specimen.

[0051] The test results of Example 1 and Comparative Example 1 show that the tensile properties of Example 1 are significantly better than those of Comparative Example 1. The initial crack tensile strength and ultimate elongation of Example 1 are 23.3% and 19.8% higher than those of Comparative Example 1, respectively. Under the same volume ratio of fiber addition, the notched PE fiber exhibits an anchoring effect in the cement matrix similar to steel fiber, which can inhibit the development and expansion of cracks, delay the appearance of the first crack, and improve the initial crack tensile strength (e.g., ...). Figure 4 As shown in the figure, in addition, the notched PE fiber and the ultra-high molecular weight PE fiber form a complementary stress system, which generates more fine cracks in the matrix, slows down the failure rate of the matrix, and effectively improves the ultimate tensile strain of the specimen.

[0052] The test results of Example 1 and Comparative Examples 1 and 2 show that the anchoring effect of steel fibers in cement matrix is ​​better than that of indented polyethylene fibers, which can significantly improve the initial crack strength of the mixture. However, the corresponding increase in initial crack strength leads to a decrease in the effect of polyethylene fibers in strain hardening and multi-point cracking, and the ultimate tensile strain of the mixture is significantly reduced.

[0053] The test results of Comparative Examples 4 and 5 show that under the mix proportion of high-strength cement matrix, polyvinyl alcohol fibers are unable to exert their strain hardening and multi-point cracking characteristics, and the ultimate tensile strain of the mixture is very small.

[0054] As shown in Table 2, the mechanical properties of Examples 1-3 all meet the design requirements.

[0055] In summary, this invention prepares a polyethylene-reinforced high-toughness cement-based composite material with good flowability, which can reduce construction difficulty, improve construction efficiency, and meet the performance requirements of continuous sections of steel-concrete composite beam bridge decks.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A polyethylene reinforced high ductility cementitious composite material, characterized in that, By weight, it consists of the following components: 600-700 parts cement, 700-900 parts quartz sand, 280-380 parts fly ash, 80-120 parts silica fume, 80-120 parts precipitated beads, 45-55 parts CSA expanding agent, 5-8 parts high-performance polycarboxylate superplasticizer, 5-8 parts notched polyethylene fiber, 10-15 parts ultra-high molecular weight polyethylene fiber, and 320-390 parts water.

2. The polyethylene reinforced high ductility cementitious composite material of claim 1, wherein, The cement is P·O42.5 ordinary portland cement, and the bulk density of the sinker is 800-1000kg / m 3 .

3. The polyethylene reinforced high ductility cementitious composite material of claim 1, wherein, The quartz sand has a particle size of 80-120 mesh, and the CSA expanding agent contains ≤5wt% magnesium oxide and ≤0.75wt% alkali.

4. The polyethylene-reinforced high-toughness cement-based composite material as described in claim 1, characterized in that, The parameters of the notched polyethylene fiber are 15-20 mm in length, 800-1000 Mpa in tensile strength, the tensile strength of the ultra-high molecular weight polyethylene fiber is ≥3000 Mpa, and the equivalent bending strength is 9-14 N / mm 2 .

5. The polyethylene-reinforced high-toughness cement-based composite material as described in claim 1, characterized in that, The polyethylene-reinforced high-toughness cement-based composite material has a compressive strength ≥55 MPa, a flexural strength ≥10 MPa, an elastic modulus ≥20 GPa, an initial crack tensile strength ≥3 MPa, and an ultimate tensile strain ≥1.5%.

6. A method for preparing a polyethylene-reinforced high-toughness cement-based composite material according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Mix quartz sand, cement, fly ash, silica fume, sedimentary beads, and CSA expansion agent evenly to obtain dry material; S2. Add polycarboxylate superplasticizer to water to prepare polycarboxylate superplasticizer solution, add polycarboxylate superplasticizer solution to dry material and continue stirring to mix evenly to obtain cement mortar; S3. Add ultra-high molecular weight polyethylene fiber and notched polyethylene fiber to cement mortar in batches and continue to stir and mix to obtain a mixture. S4. Pour the mixture into the mold, and then vibrate and cure it to obtain the final product.

7. The method for preparing polyethylene-reinforced high-toughness cement-based composite material as described in claim 6, characterized in that, In steps S1-S3, the mixing time is 20-40s, 90-120s and 120-150s respectively, and the mixing speed is 55-60r / min.

8. The method for preparing polyethylene-reinforced high-toughness cement-based composite material as described in claim 6, characterized in that, In step S4, the vibration molding time is 60-80 seconds, the curing time is 28 days, the curing humidity is above 95%, and the temperature is 20±2℃.

9. The application of the polyethylene-reinforced high-toughness cement-based composite material according to any one of claims 1-5 in the bridge deck connection of a steel-concrete composite beam bridge.

10. A method for connecting the deck of a steel-concrete composite beam bridge, characterized in that, The polyethylene-reinforced high-toughness cement-based composite material according to any one of claims 1-5 is cast at the bridge deck connection of the steel-concrete composite beam bridge.

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