Ultra-high performance concrete material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of electric power engineering, in particular to an ultra-high performance concrete material and a preparation method and application thereof. The ultra-high-performance concrete material comprises cement, silica fume, recycled coarse aggregate, recycled fine aggregate, blast furnace slag, a composite fiber material and an additive, and the ultra-high-performance concrete material has good strength and durability by utilizing the synergistic effect of all the component raw materials. In addition, a large amount of recycled aggregate exists in the raw materials, so that the preparation cost of the concrete material is greatly reduced. The problems that an existing UHPC electric pole is insufficient in strength, poor in durability and high in preparation cost are effectively solved, and a new thought is provided for development of the UHPC electric pole.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power engineering, and particularly relates to an ultra-high performance concrete material, a preparation method thereof, and an application thereof. Background Art

[0002] Concrete poles are a widely used pole structure form in the field of overhead lines in our country. Due to the popularization of ultra-high voltage transmission lines and the increase in per capita electricity consumption, the loads borne by transmission poles have gradually increased. Traditional concrete transmission poles are prone to accidents such as cracking and overturning when encountering strong winds, hailstorms, and vehicle impacts due to their low compressive and flexural strengths, seriously endangering people's lives and property safety. With the improvement of environmental awareness, in order to save land resources and ensure the safe operation of the line, poles with guy wires are gradually phased out, and the application scope of traditional concrete transmission poles has become narrower, and the market is slowly shrinking.

[0003] Ultra-high performance concrete (UHPC) is a major technological innovation in the field of contemporary building materials. This new type of cement-based composite material is gradually changing the face of modern buildings and engineering structures with its excellent physical properties and broad application prospects. Due to its ultra-high compressive strength, tensile strength, and excellent durability, UHPC has been widely used in projects such as high-rise buildings, bridges, and transmission lines in our country. The incorporation of fibers and aggregates can improve the ductility of concrete and reduce production costs, which makes UHPC have broad application prospects in the field of transmission lines. However, most current UHPC poles are often manufactured by the centrifugal molding process and steel fibers are incorporated to increase strength. Since steel fibers have a relatively large self-weight and poor corrosion resistance, the fibers are easily pulled out during molding, resulting in poor durability of the poles. In a humid environment, the steel fibers will corrode, leading to potential safety hazards inside the concrete poles. When encountering impact loads, a large number of traditional UHPC poles will experience accidents such as broken poles, fallen poles, and inclined poles, resulting in large-scale power outages and seriously threatening the safe operation of the power system; in addition, most traditional UHPC is prepared by removing coarse aggregates and using a large amount of expensive quartz sand, which greatly increases the manufacturing cost of UHPC poles. Therefore, it is very meaningful to develop an ultra-high performance concrete pole with low cost and high safety in the field of transmission lines. Summary of the Invention

[0004] Aiming at the problems of insufficient strength, poor durability and high preparation cost of existing UHPC poles, the present invention provides a super high performance concrete material, its preparation method and application. The super high performance concrete material includes cement, silica fume, recycled coarse aggregate, recycled fine aggregate, blast furnace slag, composite fiber material and admixture. By utilizing the synergistic effect of each component raw material, the concrete material has good strength and durability, and due to the large amount of recycled aggregate in the raw materials, the cost of the concrete material is greatly reduced.

[0005] To achieve the above invention purpose, the present invention provides the following technical solutions: The first aspect of the present invention provides a super high performance concrete material, including the following raw material components in parts by mass: 510 - 590 parts of cement, 60 - 80 parts of silica fume, 486 - 786 parts of recycled fine aggregate, 900 - 1200 parts of recycled coarse aggregate, 280 - 320 parts of blast furnace slag, 70 - 90 parts of composite fiber material, 50 - 70 parts of admixture and 163 - 200 parts of water; the composite fiber material includes ultra-high molecular weight polyethylene fiber, waste PP fiber and basalt fiber; the admixture includes walnut shell sintered powder, expansive agent, water reducing agent and internal curing agent.

[0006] Compared with the prior art, the present invention designs a super high performance concrete material with high strength and long durability. The present invention uses a composite fiber material to replace ordinary steel fiber, which not only avoids the potential hidden dangers caused by the corrosion of steel fiber after long-term use, but also can avoid the phenomena of honeycombing and pitting on the surface of the pole during the forming process. And because the composite fiber material is a lightweight fiber material such as ultra-high molecular weight polyethylene fiber, waste PP fiber and basalt fiber, it can effectively reduce the self-weight of the pole, facilitate transportation and reduce transportation costs. More importantly, the composite fiber material can also prevent the concrete from appearing plastic shrinkage cracks and improve the toughness of the hardened concrete. The present invention also uses a large amount of recycled aggregate, effectively alleviating the treatment pressure of solid waste materials, greatly saving production costs, and helping to reduce the exploitation of natural resources and the damage to the ecological environment. Silica fume can fill the pores between cement particles, change the working performance of the mixture and improve the strength of the concrete material.

[0007] The present invention also adds an admixture to the concrete material. Among them, the addition of walnut shell sintered powder can act as a lightweight aggregate, improve the pore structure and water permeability of the concrete, and prevent the recycled aggregate and composite fiber material from being eroded. And walnut shell sintered powder can also increase the overall density of the concrete, thereby enhancing the strength and durability of the concrete material. The use of the water reducing agent can further reduce the water-binder ratio, and the defoaming agent can reduce the bubbles generated during the forming process of the concrete, reduce the porosity inside the concrete and improve the compactness of the concrete.

[0008] In summary, by utilizing the synergistic effect of each raw material component, the concrete material of the present invention has good strength and durability, and due to the large amount of recycled aggregate in the raw materials, the cost of the concrete material is greatly reduced. The present invention effectively solves the problems of insufficient strength, poor durability and high preparation cost of UHPC poles in the prior art.

[0009] Preferably, the cement is 52.5 ordinary Portland cement or Portland cement.

[0010] Preferably, the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber and basalt fiber with a mass ratio of 1:1.5:2.5 - 1:2:2.5.

[0011] Preferably, the length of the ultra-high molecular weight polyethylene fiber is 25 mm - 30 mm.

[0012] Preferably, the length of the waste PP fiber is 20 mm - 30 mm.

[0013] Preferably, the length of the basalt fiber is 10 mm - 20 mm.

[0014] Preferably, the admixture includes the following raw material components by mass percentage: 20% - 35% of walnut shell sintered powder, 20% - 25% of expansion agent, 30% - 45% of water reducer and 15% - 30% of internal curing agent.

[0015] Further preferably, the preparation method of the walnut shell sintered powder includes the following steps: crushing the walnut shell, calcining at 650°C - 800°C, and grinding to obtain the walnut shell sintered powder.

[0016] Even more preferably, the calcination time is 6 h - 10 h.

[0017] Even more preferably, the temperature is raised to 650°C - 800°C by means of programmed heating, and the heating rate is 5°C / min - 10°C / min.

[0018] Even more preferably, the particle size of the walnut shell sintered powder is 100 μm - 200 μm.

[0019] Preferably, the specific surface area of the silica fume is 20000 m 2 / kg - 25000 m 2 / kg, and the content of SiO 2 ≥90%.

[0020] Preferably, the particle size of the recycled coarse aggregate is 5 mm - 10 mm, and the water content ≤10%.

[0021] Preferably, the particle size of the recycled fine aggregate is 0.5 mm - 1 mm, and the water content is ≤ 10%.

[0022] Preferably, the specific surface area of the blast furnace slag is 28,000 m 2 / kg - 32,000 m 2 / kg, the grading ratio is 10% - 30%, and the particle size is 1 mm - 1.5 mm.

[0023] More preferably, the internal curing agent is a SAP internal curing agent, and the particle size is 0.1 mm - 0.3 mm.

[0024] More preferably, the particle size of the expansive agent is 2 μm - 15 μm.

[0025] More preferably, the water reducing agent is a polycarboxylate water reducing agent.

[0026] More preferably, the expansive agent is an HP-CSA type composite expansive agent.

[0027] The second aspect of the present invention provides a preparation method of the ultra-high performance concrete material as described above, comprising the following steps: weighing each component raw material according to the designed ratio, and mixing evenly to obtain the ultra-high performance concrete material.

[0028] The third aspect of the present invention provides an ultra-high performance concrete pole, comprising the ultra-high performance concrete material according to any one of claims 1 - 8, a steel cage skeleton, and a thin-walled steel pipe, wherein the steel cage skeleton comprises prestressed longitudinal bars, ordinary longitudinal bars, spiral stirrups, and erection rings.

[0029] Preferably, the material of the prestressed longitudinal bars is high-strength steel wires with a diameter of 4.5 mm - 5 mm.

[0030] The prestressed steel bars are pre-stretched during the production process of the pole, so as to generate pre-compressive stress in the concrete. This pre-applied internal stress already exists before the pole bears external loads. The pre-existing compressive stress inside can offset or reduce the tensile stress generated by the external loads, thereby effectively preventing the concrete from cracking and improving the bearing capacity of the pole and the stability of the overall structure.

[0031] Preferably, the material of the ordinary longitudinal bars is HRB335 hot-rolled ribbed steel bars with a diameter of 5 mm - 7 mm.

[0032] Preferably, the material of the spiral stirrups is cold-drawn steel bars with a diameter of Ф2.5.

[0033] Preferably, the material of the erection rings is cold-drawn steel bars with a diameter of Ф4.5.

[0034] The erection ring is located horizontally on the pole, which can effectively improve the flexural performance of the pole. When the pole is subjected to bending force, the erection ring can enhance the lateral stiffness of the pole and prevent excessive deformation of the pole under the action of bending moment. In the process of using the mechanical roll welding forming method to combine with the steel ring to form the steel reinforcement cage in the present invention, the steel bars are arranged in accordance with the distribution principle of the longitudinal bars of the reinforced concrete pole. The erection rings used have the same size, and their main function is to fix the position of the longitudinal bars, ensure that the wall thickness of the circular ring of the pole meets the design requirements, and at the same time enhance the overall stiffness of the steel reinforcement cage to avoid deformation of the steel reinforcement cage during the centrifugal forming process. After the production of the longitudinal bar cage is completed, the welding operation of the spiral stirrup is carried out. For the encrypted steel bars, customized spiral stirrups are used. After the production of the steel reinforcement cage is completed, a detailed inspection is required to ensure the structural stability of the skeleton without looseness or distortion to meet the design and construction quality requirements.

[0035] Preferably, the thin-walled steel pipe is made of galvanized steel pipe.

[0036] Preferably, the thickness of the thin-walled steel pipe is 3 mm - 4 mm.

[0037] The thin-walled galvanized steel pipe is usually located at the bottom of the pole, and its length is determined according to the height of the pole and the design requirements. The wall thickness uniformity of the steel pipe is increased through special cold rolling processing to ensure that the pipe is not easily deformed or ruptured under pressure. The steel pipe can also improve the bending resistance of the pole. At the same time, the galvanized steel pipe has the advantages of high surface gloss, uniform zinc layer, no missing plating, no dripping, strong adhesion, and strong corrosion resistance, which can effectively improve the durability and aesthetics of the pole.

[0038] In summary, the present invention provides a ultra-high performance concrete material, which uses composite fiber materials to replace traditional steel fibers, and adds walnut shell sintered powder as an admixture. Combining with other raw material components endows the ultra-high performance concrete material with good mechanical strength and durability. Using the technical solution of the present invention effectively solves the problems of insufficient strength, poor durability and high preparation cost of the existing UHPC poles, and provides a new idea for the development of UHPC poles. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the overall structure of the UHPC pole prepared by using the ultra-high performance concrete material provided in Embodiment 1 of the present invention; wherein, 1 is the pole body; 2 is the warning sign; 3 is the longitudinal bar duct; 4 is the chassis; 5 is the bolt hole; Figure 2 It is a cross-sectional view of the UHPC pole prepared by using the ultra-high performance concrete material provided in Embodiment 1 of the present invention; Figure 3Schematic diagram of the UHPC pole skeleton prepared from the ultra-high performance concrete material provided in Embodiment 1 of the present invention; wherein, 6 is a spiral stirrup; 7 is a prestressed longitudinal bar; 8 is ultra-high performance concrete; 9 is a common longitudinal bar; 10 is a thin-walled steel pipe; 11 is a erection ring. Detailed implementation mode

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Embodiment 1 This embodiment provides a preparation method of an ultra-high performance concrete material, which specifically includes the following contents: The ultra-high performance concrete material includes the following raw material components in parts by mass: 590 parts of 52.5 Portland cement, 70 parts of silica fume, 490 parts of recycled fine aggregate, 900 parts of recycled coarse aggregate, 300 parts of blast furnace slag, 80 parts of composite fiber material, 60 parts of admixture and 170 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber and basalt fiber with a mass ratio of 1:1.5:2.5; the admixture includes the following raw material components in mass percentage: 25% of walnut shell sintered powder, 22% of HP-CSA type composite expansion agent, 35% of polycarboxylate water reducing agent and 18% of SAP internal curing agent.

[0042] The preparation method of the ultra-high performance concrete material includes the following steps: weighing each component raw material according to the designed ratio and mixing evenly to obtain the ultra-high performance concrete material.

[0043] Among them, the preparation method of the walnut shell sintered powder includes the following steps: crushing 500 g of walnut shells, heating at a heating rate of 10 °C / min to 750 °C for calcination for 8 h, and grinding to obtain walnut shell sintered powder with a particle size of 150 μm.

[0044] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 ≥90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the grading rate is 22.8%, and the particle size is 1.2 mm.

[0045] Example 2 This example provides a preparation method of ultra-high performance concrete materials, which specifically includes the following contents: The ultra-high performance concrete materials include the following raw material components in parts by mass: 565 parts of 52.5 Portland cement, 65 parts of silica fume, 562 parts of recycled fine aggregate, 1000 parts of recycled coarse aggregate, 320 parts of blast furnace slag, 75 parts of composite fiber material, 65 parts of admixture, and 190 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber, and basalt fiber with a mass ratio of 1:1.8:2.5; the admixture includes the following raw material components in mass percentage: 35% of walnut shell sintered powder, 20% of HP-CSA type composite expansive agent, 30% of polycarboxylate water reducer, and 15% of SAP internal curing agent.

[0046] The preparation method of the ultra-high performance concrete materials includes the following steps: Weigh each component raw material according to the designed ratio and mix them evenly to obtain the ultra-high performance concrete materials.

[0047] Among them, the preparation method of the walnut shell sintered powder includes the following steps: Crush 500 g of walnut shells, heat them at a heating rate of 10 °C / min to 750 °C for calcination for 8 h, and grind them to obtain walnut shell sintered powder with a particle size of 150 μm.

[0048] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 ≥90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the grading rate is 22.8%, and the particle size is 1.2 mm.

[0049] Example 3 This example provides a preparation method of ultra-high performance concrete materials, which specifically includes the following contents: The ultra-high performance concrete material includes the following raw material components in parts by mass: 515 parts of 52.5-grade Portland cement, 70 parts of silica fume, 486 parts of recycled fine aggregate, 1200 parts of recycled coarse aggregate, 320 parts of blast furnace slag, 70 parts of composite fiber material, 63 parts of admixture, and 170 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber, and basalt fiber with a mass ratio of 1:1.5:2.5; the admixture includes the following raw material components in mass percentage: 20% of walnut shell sintered powder, 25% of HP-CSA type composite expansion agent, 40% of polycarboxylate water reducer, and 15% of SAP internal curing agent.

[0050] The preparation method of the ultra-high performance concrete material includes the following steps: Weigh each component raw material according to the designed ratio and mix them evenly to obtain the ultra-high performance concrete material.

[0051] Among them, the preparation method of the walnut shell sintered powder includes the following steps: Crush 500 g of walnut shells, heat them at a heating rate of 10 °C / min to 750 °C for calcination for 8 h, and grind them to obtain walnut shell sintered powder with a particle size of 150 μm.

[0052] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 ≥90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the grading rate is 22.8%, and the particle size is 1.2 mm.

[0053] Example 4 This example provides a preparation method of an ultra-high performance concrete material, which specifically includes the following content: The ultra-high performance concrete material includes the following raw material components in parts by mass: 582 parts of 52.5-grade Portland cement, 70 parts of silica fume, 750 parts of recycled fine aggregate, 900 parts of recycled coarse aggregate, 300 parts of blast furnace slag, 76 parts of composite fiber material, 60 parts of admixture, and 200 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber, and basalt fiber with a mass ratio of 1:1.5:2.5; the admixture includes the following raw material components in mass percentage: 23% of walnut shell sintered powder, 24% of HP-CSA type composite expansion agent, 36% of polycarboxylate water reducer, and 17% of SAP internal curing agent.

[0054] The preparation method of the ultra-high performance concrete material comprises the following steps: weighing each component raw material according to the designed ratio and mixing them evenly to obtain the ultra-high performance concrete material.

[0055] Among them, the preparation method of the walnut shell sintered powder comprises the following steps: crushing 500 g of walnut shells, heating them to 750 °C at a heating rate of 10 °C / min for calcination for 8 h, and grinding to obtain walnut shell sintered powder with a particle size of 150 μm.

[0056] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 ≥90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the grading ratio is 22.8%, and the particle size is 1.2 mm.

[0057] Example 5 This example provides a preparation method of an ultra-high performance concrete material, which specifically comprises the following contents: The ultra-high performance concrete material comprises the following raw material components in parts by mass: 545 parts of 52.5-grade Portland cement, 70 parts of silica fume, 596 parts of recycled fine aggregate, 900 parts of recycled coarse aggregate, 300 parts of blast furnace slag, 73 parts of composite fiber material, 60 parts of admixture, and 170 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber, and basalt fiber with a mass ratio of 1:1.7:2.5; the admixture comprises the following raw material components in mass percentage: 30% of walnut shell sintered powder, 20% of HP-CSA type composite expansion agent, 32% of polycarboxylate water reducer, and 18% of SAP internal curing agent.

[0058] The preparation method of the ultra-high performance concrete material comprises the following steps: weighing each component raw material according to the designed ratio and mixing them evenly to obtain the ultra-high performance concrete material.

[0059] Among them, the preparation method of the walnut shell sintered powder comprises the following steps: crushing 500 g of walnut shells, heating them to 750 °C at a heating rate of 10 °C / min for calcination for 8 h, and grinding to obtain walnut shell sintered powder with a particle size of 150 μm.

[0060] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 is ≥ 90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the gradation rate is 22.8%, and the particle size is 1.2 mm.

[0061] Comparative Example 1 This comparative example provides a preparation method of an ultra-high performance concrete material. The difference from Example 1 is that: in the admixture, rubber powder with a particle size of 150 μm is used to replace the walnut shell sintered powder, and other components and parameters remain unchanged. The specific contents are as follows: The ultra-high performance concrete material includes the following raw material components in parts by mass: 590 parts of 52.5-grade Portland cement, 70 parts of silica fume, 490 parts of recycled fine aggregate, 900 parts of recycled coarse aggregate, 300 parts of blast furnace slag, 80 parts of composite fiber material, 60 parts of admixture, and 170 parts of water; the composite fiber material is ultra-high molecular weight polyethylene fiber, waste PP fiber, and basalt fiber with a mass ratio of 1:1.5:2.5; the admixture includes the following raw material components in mass percentage: 25% of walnut shell sintered powder, 22% of HP-CSA type composite expansion agent, 35% of polycarboxylate water reducer, and 18% of SAP internal curing agent.

[0062] The preparation method of the ultra-high performance concrete material includes the following steps: Weigh each component raw material according to the designed ratio, and mix them evenly to obtain the ultra-high performance concrete material.

[0063] The length of the ultra-high molecular weight polyethylene fiber is 25 mm, the length of the waste PP fiber is 20 mm, and the length of the basalt fiber is 15 mm; The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 is ≥ 90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the gradation rate is 22.8%, and the particle size is 1.2 mm.

[0064] Comparative Example 2 This comparative example provides a preparation method of an ultra-high performance concrete material. The difference from Example 1 is that: the composite fiber material is replaced with steel fiber with a length of 15 mm and a self-strength of 2500 MPa, and other components and parameters remain unchanged. The specific contents are as follows: The ultra-high performance concrete material includes the following raw material components by mass parts: 590 parts of 52.5-grade Portland cement, 70 parts of silica fume, 490 parts of recycled fine aggregate, 900 parts of recycled coarse aggregate, 300 parts of blast furnace slag, 80 parts of steel fiber, 60 parts of admixture, and 170 parts of water; the admixture includes the following raw material components by mass percentage: 25% of walnut shell sintered powder, 22% of HP-CSA type composite expansive agent, 35% of polycarboxylate water reducer, and 18% of SAP internal curing agent.

[0065] The preparation method of the ultra-high performance concrete material includes the following steps: Weigh each component raw material according to the designed ratio, and mix them evenly to obtain the ultra-high performance concrete material.

[0066] Among them, the preparation method of the walnut shell sintered powder includes the following steps: Crush 500 g of walnut shells, heat them at a heating rate of 10 °C / min to 750 °C, calcine for 8 h, and grind to obtain walnut shell sintered powder with a particle size of 150 μm.

[0067] The specific surface area of the silica fume is 25000 m 2 / kg, and the content of SiO 2 ≥90%; the particle size of the recycled coarse aggregate is 8 mm, and the water content is 7.2%; the particle size of the recycled fine aggregate is 0.8 mm, and the water content is 6.4%; the specific surface area of the blast furnace slag is 30000 m 2 / kg, the grading rate is 22.8%, and the particle size is 1.2 mm.

[0068] In order to further demonstrate the technical effects of the present invention, the ultra-high performance concrete materials obtained in Examples 1-5 and Comparative Examples 1-2 of the present invention are made into UHPC poles, and the schematic diagram of the UHPC pole is as Figures 1-3 shown. Among them, the steel cage skeleton is wrapped in the ultra-high performance concrete 8. The main bars of the steel cage skeleton are composed of two types of bars arranged at intervals, namely prestressed longitudinal bars 7 and ordinary longitudinal bars 9, spiral stirrups 6 and erection rings 11; the ordinary longitudinal bars 9 and prestressed longitudinal bars 7 are welded and fixed with erection rings 11, Figure 2 which is the cross-sectional view of the UHPC pole provided by the present invention.

[0069] The preparation method of the UHPC pole is as follows: Step 1: Cut and weld the steel bars to make them into the required shapes and sizes. For prestressed concrete poles, prestress tensioning is also required, and they are tied into a steel cage skeleton.

[0070] Step 2: Prepare ultra-high performance concrete containing coarse aggregate.

[0071] Step 3: Put the mixed concrete into the mold, and then place the mold in a centrifuge for forming; subject the formed electric poles to atmospheric steam curing.

[0072] The process parameters of the centrifugal forming are shown in Table 1: Table 1 Process parameters of centrifugal forming

[0073] The atmospheric steam curing includes a heating period, a constant temperature period, and a cooling period. The specific process parameters are shown in Tables 2 - 4: Table 2 Process parameters of atmospheric steam curing in the heating period

[0074] Table 3 Process parameters of atmospheric steam curing in the constant temperature period

[0075] Table 4 Process parameters of atmospheric steam curing in the cooling period

[0076] After the curing of the electric poles is completed, apply a layer of polyurethane waterproof coating in the area 1.2 m from the bottom of the electric poles. During the embedding process of the electric poles, the electric poles can be directly fixed to the chassis with bolts and buried underground. On the one hand, the electric pole chassis can provide an additional fixing function for the electric poles, ensuring that the electric poles can stand firmly on the ground after installation and are not easily displaced or tilted. On the other hand, the electric pole chassis can reduce the erosion of groundwater and rainwater on the roots of the electric poles, preventing the bottom of the electric poles from sinking or tilting due to water erosion or soil loosening, and increasing the stability of the electric poles.

[0077] The present invention carried out mechanical property tests on the ultra-high performance concrete materials obtained in Examples 1 - 5 and Comparative Example 1 according to GB / T50080 - 2016. The specific test results are shown in Table 5.

[0078] Table 5 Test results of the mechanical properties of ultra-high performance concrete materials

[0079] The present invention also carried out relevant tests on the durability of UHPC electric poles prepared from the ultra-high performance concrete materials obtained in Examples 1 - 5 and Comparative Examples 1 - 2 according to GB / T4623 - 2014. The results are shown in Table 6.

[0080] Table 6 Test results of UHPC electric poles

[0081] As can be seen from Table 5 and Table 6, the ultra-high performance concrete materials provided in Embodiments 1-5 of the present invention have excellent mechanical properties; the UHPC poles prepared using the ultra-high performance concrete materials have ultra-high mechanical properties and durability.

[0082] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ultra-high performance concrete material, characterized in that: The invention comprises the following raw material components in parts by weight: 510-590 parts of cement, 60-80 parts of silica fume, 486-786 parts of recycled fine aggregate, 900-1200 parts of recycled coarse aggregate, 280-320 parts of blast furnace slag, 70-90 parts of composite fiber materials, 50-70 parts of admixtures and 163-200 parts of water; the composite fibers comprise ultra-high molecular weight polyethylene fibers, waste PP fibers and basalt fibers; the admixtures comprise walnut shell sintered powder, an expansion agent, a water reducing agent and an internal curing agent.

2. The ultra-high performance concrete material according to claim 1, characterized in that: The composite fiber material is ultra-high molecular polyethylene fiber, waste PP fiber and basalt fiber in a mass ratio of 1:1.5:2.5-1:2:2.

5.

3. The ultra-high performance concrete material according to claim 1 or 2, characterized in that: The length of the ultra-high molecular weight polyethylene fiber is 25mm-30mm; and / or The length of the waste PP fibers is 20 mm to 30 mm; and / or The length of the basalt fiber is 10 mm-20 mm.

4. The ultra-high performance concrete material according to claim 1, characterized in that: The admixture includes the following raw material components in percentage by mass: 20%-35% of walnut shell sintered powder, 20%-25% of expansion agent, 30%-45% of water reducing agent and 15%-30% of internal curing agent.

5. The ultra-high performance concrete material according to claim 4, characterized in that: The preparation method of the walnut shell sintered powder comprises the following steps: crushing the walnut shell, calcining at 650° C.-800° C., and grinding to obtain the walnut shell sintered powder.

6. The ultra-high performance concrete material according to claim 5, characterized in that: The calcination time is 6h-10h; and / or The temperature is raised to 650°C-800°C by programmed heating at a rate of 5°C / min-10°C / min; and / or The particle size of the walnut shell sintered powder is 100 μm-200 μm.

7. The ultra-high performance concrete material according to claim 1, characterized in that: The specific surface area of ​​the silica fume is 20000m 2 / kg-25000m 2 / kg, SiO2 content ≥ 90%; and / or The particle size of the recycled coarse aggregate is 5mm-10mm, and the water content is ≤10%; and / or The particle size of the recycled fine aggregate is 0.5mm-1mm, and the water content is ≤10%; and / or The specific surface area of ​​the blast furnace slag is 28000m 2 / kg-32000m 2 / kg, the grading rate is 10%-30%, and the particle size is 1mm-1.5mm.

8. The ultra-high performance concrete material according to claim 3, characterized in that: The internal curing agent is a SAP internal curing agent with a particle size of 0.1 mm to 0.3 mm; and / or The particle size of the expansion agent is 2 μm-15 μm.

9. A method for preparing the ultra-high performance concrete material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: weighing raw materials of various components according to the designed proportion, mixing them evenly, and obtaining ultra-high performance concrete material.

10. An ultra-high performance concrete pole, characterized in that: It comprises the ultra-high performance concrete material according to any one of claims 1 to 8, a steel cage skeleton and a thin-walled steel pipe, wherein the steel cage skeleton comprises prestressed longitudinal bars, ordinary longitudinal bars, spiral stirrups and erection rings.

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