Ultra-high performance concrete material and construction method and application thereof

Abstract

The application provides a kind of ultra-high performance concrete material and its construction method, application, it is related to the technical field of bridge maintenance, the ultra-high performance concrete material includes the following components: Portland cement, mineral powder, fly ash, silica fume, plated copper short end hook steel fiber, quartz sand, admixture, silicon dioxide, BEFORM fast hardening agent and water.The application introduces plated copper short end hook steel fiber and BEFORM fast hardening agent, under the synergistic effect of various components, by using alternate layer pouring and temperature gradient curing technology, effectively solves the technical problems of low bonding strength, poor durability and long curing period in traditional bridge expansion joint maintenance, achieves the technical effect of forming a maintenance-free overall system, significantly prolongs the service life of the bridge.

Description

Technical Field

[0001] This invention relates to the technical field of bridge maintenance, and in particular to an ultra-high performance concrete material, its construction method, and its application. Background Technology

[0002] With the development of urban transportation and the improvement of road networks, bridges, as an important component of transportation hubs, have received high attention for their safety and durability. Bridge expansion joints are critical weak points in bridge structures. They are subjected to vehicle loads, temperature deformation, and rainwater erosion over long periods, making them prone to defects such as concrete spalling, loosening of steel comb teeth, and waterproofing failure. These issues affect the performance of the bridge structure and pose safety hazards.

[0003] Traditional methods for repairing bridge expansion joints often use ordinary concrete or quick-drying concrete, which have the following drawbacks: insufficient bond strength, with the interface between new and old concrete prone to delamination due to differences in heat of hydration; low construction efficiency, as ordinary concrete has a long setting time, requiring prolonged traffic closure; poor durability, as traditional materials have insufficient impermeability, are susceptible to chloride ion corrosion, are not acid or alkali resistant, and have weak UV resistance; poor crack resistance, as traditional materials are prone to cracking; and poor strength, with the 28-day compressive strength of ordinary concrete not exceeding 50 MPa.

[0004] While existing ultra-high performance concrete (UHPC) materials possess high strength and high durability, they suffer from problems such as long hardening time, poor fluidity, large shrinkage, and poor adhesion to existing structures when directly applied to expansion joint repair.

[0005] Therefore, there is an urgent need to develop a UHPC material and corresponding construction process that combines high strength, rapid curing and adaptive deformation capabilities.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] One of the objectives of this invention is to provide an ultra-high performance concrete material that can solve the technical problems of low bonding strength, low construction efficiency, poor durability, and easy cracking of traditional bridge expansion joint repair materials with existing concrete.

[0008] The second objective of this invention is to provide an application of ultra-high performance concrete material that can form a maintenance-free integrated system, which can significantly extend the service life of bridges.

[0009] The third objective of this invention is to provide a construction method for ultra-high performance concrete materials, which has good construction effect and high construction efficiency.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: Firstly, an ultra-high performance concrete material comprises the following components: Silicate cement, mineral powder, fly ash, silica fume, copper-plated short-end hook steel fiber, quartz sand, admixtures, silica, BEFORM rapid hardening agent, and water.

[0011] Furthermore, the silicate cement includes 52.5 grade ordinary silicate cement.

[0012] Furthermore, the mineral powder comprises calcium silicate and calcium aluminosilicate; Preferably, the particle size of the mineral powder is below 45 μm; Preferably, the specific surface area of ​​the mineral powder is 400 m². 2 / kg-600m 2 / kg, with a bulk density of 1050kg / m³ 3 -1375kg / m 3 .

[0013] Furthermore, the fly ash includes Class I fly ash; Preferably, the particle size of the fly ash is not greater than 80 μm; Preferably, the silica fume comprises semi-densified silica fume.

[0014] Furthermore, the copper-plated short-end hook steel fiber has a length of 10mm-30mm and a diameter of 0.2mm-0.3mm; Preferably, the tensile strength of the copper-plated short-end hook steel fiber is ≥2800MPa.

[0015] Furthermore, the quartz sand includes at least one of the following: quartz sand with a particle size of 630μm-830μm, quartz sand with a particle size of 212μm-630μm, and quartz sand with a particle size of 125μm-187.5μm. Preferably, the silicon dioxide comprises nano-silicon dioxide; Preferably, the admixture includes a water-reducing agent; Preferably, the water-reducing agent includes a polycarboxylate water-reducing agent.

[0016] Furthermore, the ultra-high performance concrete material comprises the following components in parts by weight: 780-830 parts silicate cement, 1-50 parts mineral powder, 84-124 parts fly ash, 140-180 parts silica fume, 120-180 parts copper-plated short-end hook steel fiber, 908-1118 parts quartz sand, 26-36 parts polycarboxylate superplasticizer, 10-30 parts nano silica, 30-70 parts BEFORM rapid hardening agent, and 170-190 parts water.

[0017] Secondly, the application of any of the above-mentioned ultra-high performance concrete materials in bridge maintenance.

[0018] Furthermore, the bridge maintenance includes the maintenance of bridge expansion joints.

[0019] Thirdly, a construction method for the ultra-high performance concrete material described in any one of the above claims includes the following steps: The ultra-high performance concrete material is poured using an alternating layered pouring technique and cured using a temperature gradient curing technique. Preferably, an alternating layered pouring technique is used: the layer thickness is controlled between 300mm and 500mm, a portion is poured first, and then adjacent or symmetrical portions are poured, alternating between the two, and the interval between pouring adjacent layers or adjacent blocks does not exceed the initial setting time of the concrete. Preferably, temperature gradient curing technology is used for curing: the curing process is divided into heating, constant temperature and cooling; wherein, the heating rate is not greater than 12℃ / h, the cooling rate is not greater than 15℃ / h, the constant temperature is controlled at 80±5℃, and the constant temperature curing time is not less than 48 hours; when the insulation facilities are removed, the difference between the surface temperature of the component and the ambient temperature does not exceed 20℃.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects: The ultra-high performance concrete material provided by this invention incorporates copper-plated short-end hooked steel fibers. These hooks provide strong mechanical anchoring, effectively inhibiting crack propagation and significantly enhancing tensile strength and toughness. The short steel fibers are also easier to disperse, reducing the "wall effect" and optimizing bulk density at low dosages, further improving early crack resistance. Simultaneously, the added BEFORM rapid-hardening agent, based on ettringite expansion technology, is not only stable in composition and does not interfere with cement reaction, but also possesses long-term stable strength development characteristics, preventing strength decline. Its micro-expansion properties result in almost no shrinkage during hardening, leading to excellent early crack resistance and rapid early strength growth, facilitating rapid traffic opening. Furthermore, the added silica, in combination with other components, also improves impermeability. In summary, through the synergistic effect of all components, the ultra-high performance concrete material of this invention exhibits superior comprehensive performance, including outstanding durability and mechanical properties. It effectively resists the effects of various environmental erosion factors, demonstrates excellent service performance under complex environmental conditions, and significantly reduces the need for routine maintenance and its corresponding costs.

[0021] The application of the ultra-high performance concrete material provided by this invention is beneficial for repairing the problems and safety hazards of existing bridge expansion joints caused by aging and cracking, such as leakage, vehicle bouncing, and detachment. It can form a maintenance-free overall system and significantly extend the service life of bridges.

[0022] The construction method for ultra-high performance concrete provided by this invention adopts alternating layered pouring technology and temperature gradient curing technology, which not only has good construction effect but also high construction efficiency. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of bridge expansion joint repair according to one embodiment of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] According to a first aspect of the present invention, an ultra-high performance concrete (UHPC) material is provided, comprising the following components: Silicate cement, mineral powder, fly ash, silica fume, copper-plated short-end hook steel fiber, quartz sand, admixtures, silica, BEFORM rapid hardening agent, and water.

[0027] In this invention, ultra-high performance concrete material and steel expansion joints can be effectively bonded. The short-end hooked steel fibers provide strong mechanical anchoring, which can inhibit crack propagation and significantly improve tensile strength and toughness. At the same time, the short steel fibers are easier to disperse, reducing the "wall effect" and optimizing the bulk density at low dosages, which is more conducive to improving early crack resistance and forming an integral maintenance-free expansion joint system. When concrete is subjected to external forces and cracks occur, the copper-plated short-end hooked steel fibers can effectively absorb and disperse the stress around the cracks, slowing down crack propagation. The effective combination of ultra-high performance concrete material and bridge expansion joints in this invention realizes the maintenance-free operation of expansion joints, extends the service life of bridge structures, reduces the amount of maintenance work caused by cracks and other reasons, and extends the service life of expansion joints.

[0028] It should be noted that the UHPC matrix itself can maintain structural stability under extreme temperature environments (-20℃ to 500℃), exhibiting excellent environmental tolerance and effectively resisting the adverse effects caused by temperature fluctuations; at the same time, the steel fiber component can also effectively extend the service life of the material.

[0029] In this invention, the added BEFORM fast-setting agent is based on ettringite expansion technology. It is a grayish-white powder with stable composition. It not only does not interfere with the reaction of cement, but also has long-term stable strength development characteristics, and the strength will not drop. It can be applied in winter and has excellent crack resistance. Its micro-expansion makes the hardening process almost non-shrinking, so it has excellent early crack resistance and rapid early strength growth, which can achieve the goal of rapid opening of traffic.

[0030] In a preferred embodiment, the silicate cement includes, but is not limited to, grade 52.5 ordinary silicate cement; the average specific surface area of ​​grade 52.5 ordinary silicate cement can be 348 m². 2 / kg, the standard consistency water requirement is 27.6%, the average loss on ignition is 3.85%, the initial setting time is 158min, the final setting time is 208min, the 3-day flexural strength is 5.3MPa, and the 3-day compressive strength is 28.2MPa.

[0031] In this invention, mineral powder can be made by grinding blast furnace steelmaking by-products (slag). Mineral powder is a non-metallic material with hydration properties. Its main components are calcium silicate and calcium aluminosilicate. Mineral powder can improve the fluidity, water retention and pumpability of concrete, which is beneficial to improving the later strength of concrete, reducing cement usage, reducing heat of hydration, preventing temperature cracks, and improving the impermeability and corrosion resistance of concrete.

[0032] In a preferred embodiment, the particle size of the mineral powder can be below 45 μm.

[0033] In a preferred embodiment, the specific surface area of ​​the mineral powder can be 400 m². 2 / kg-600m 2 / kg, with a typical but not limiting specific surface area of, for example, 400m². 2 / kg, 420m 2 / kg, 440m 2 / kg, 460m 2 / kg, 480m 2 / kg, 500m 2 / kg, 520m 2 / kg, 540m 2 / kg, 560m 2 / kg, 580m 2 / kg, 600m 2 / kg.

[0034] In a preferred embodiment, the bulk density of the mineral powder can be 1050 kg / m³. 3 -1375kg / m 3Its typical, but not limiting, bulk density is, for example, 1050 kg / m³. 3 1100kg / m 3 1200kg / m 3 1300kg / m 3 1375kg / m 3 .

[0035] In this invention, solid waste materials such as silica fume and fly ash are used, which are highly compatible with ordinary concrete matrix. This helps to reduce the overall resource consumption and environmental burden of the concrete preparation process, demonstrating good environmental compatibility and conforming to the principle of sustainable development.

[0036] In a preferred embodiment, the fly ash includes, but is not limited to, Grade I fly ash.

[0037] It should be noted that the particle size of fly ash is no greater than 80μm.

[0038] In a preferred embodiment, the silica fume includes, but is not limited to, semi-densified silica fume, which is dark gray.

[0039] It should be noted that the SiO2 content in the silica fume can be 92.5%, the average loss on ignition can be 2.8%, the average moisture content can be 1.3%, and the water requirement ratio can be 114.

[0040] In a preferred embodiment, the copper-plated short-end hook steel fiber can be 10mm-30mm in length, with typical but non-limiting lengths such as 12mm, 14mm, 20mm, and 30mm, and the diameter can be 0.2mm-0.3mm, with typical but non-limiting diameters such as 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, and 0.3mm.

[0041] In this invention, the tensile strength of the copper-plated short-end hook steel fiber is ≥2800MPa.

[0042] In a preferred embodiment, the quartz sand includes, but is not limited to, at least one of quartz sand with a particle size of 630μm-830μm, quartz sand with a particle size of 212μm-630μm, and quartz sand with a particle size of 125μm-187.5μm, and has a mud content of ≤0.5%.

[0043] In a preferred embodiment, the silica can be nano-silica, which is more conducive to further improving the impermeability.

[0044] In a preferred embodiment, the admixture includes, but is not limited to, a water-reducing agent, which includes, but is not limited to, a high-efficiency polycarboxylate liquid water-reducing agent.

[0045] In a preferred embodiment, the ultra-high performance concrete material of the present invention comprises the following components in parts by mass: 780-830 parts silicate cement, 1-50 parts mineral powder, 84-124 parts fly ash, 140-180 parts silica fume, 120-180 parts copper-plated short-end hook steel fiber, 908-1118 parts quartz sand, 26-36 parts polycarboxylate superplasticizer, 10-30 parts nano silica, 30-70 parts BEFORM rapid hardening agent, and 170-190 parts water.

[0046] With the synergistic effect of each component and its mass ratio, the ultra-high performance concrete material of this invention is suitable for repairing bridge expansion joints. It has good compatibility and can effectively bond with expansion joints, thereby forming an integral maintenance-free expansion joint system. It can effectively improve the crack resistance and durability of expansion joint concrete, significantly improve its mechanical properties, and play a positive role in promoting the normal use of bridge structures.

[0047] According to a second aspect of the present invention, an application of the ultra-high performance concrete material described in any of the preceding claims in bridge maintenance is provided.

[0048] In this invention, bridge maintenance includes, but is not limited to, bridge expansion joint maintenance.

[0049] The application of the ultra-high performance concrete material of this invention is beneficial for repairing the problems and safety hazards of leakage, vehicle bouncing, and detachment caused by aging and cracking of existing bridge expansion joints. It can form a maintenance-free integrated system. Figure 1 This can significantly extend the service life of bridges.

[0050] According to a third aspect of the present invention, a method for constructing the ultra-high performance concrete material as described in any one of the preceding claims is provided, comprising the following steps: Ultra-high performance concrete is poured using an alternating layered pouring technique and cured using a temperature gradient curing technique.

[0051] In a preferred embodiment, an alternating layered pouring technique is used: the layer thickness is controlled between 300mm and 500mm, a portion is poured first, and then adjacent or symmetrical portions are poured, alternating between the two, with the interval between pouring adjacent layers or adjacent blocks not exceeding the initial setting time of the concrete.

[0052] In a preferred embodiment, temperature gradient curing technology is used for curing: the curing process is divided into heating, constant temperature and cooling; wherein the heating rate is no more than 12℃ / h, the cooling rate is no more than 15℃ / h, the constant temperature is controlled at 80±5℃, and the constant temperature curing time is no less than 48 hours; when the insulation facilities are removed, the difference between the surface temperature of the component and the ambient temperature does not exceed 20℃.

[0053] The construction method of the ultra-high performance concrete material of this invention adopts alternating layered pouring technology and temperature gradient curing technology, which not only has good construction effect, but also high construction efficiency.

[0054] The construction method of this invention specifically includes the following steps: S1: Expansion joint cutting and grooving and base surface treatment: roughen the concrete on both sides of the expansion joint, clean it and then apply an interface agent. S2: Expansion joint installation; S3: Template installation: Set up adjustable height steel templates, and reserve expansion joint width tolerance ±1mm; S4: UHPC Concrete Preparation: UHPC mixing first uses a crane to put the weighed UHPC premix into the mixer drum and dry mixes for about 30 seconds to make the premix flow. Then, water is added according to the proportion for wet mixing. During the mixing process, the state of the mixture is observed through the observation window. After the UHPC mixture becomes fluid, continue mixing for no less than 2 minutes, with a total mixing time of no less than 8 minutes. (1) Before mixing, the mixing equipment should be cleaned and moistened, but there should be no standing water; at the same time, the equipment should be tested to ensure that the equipment is operating normally. (2) Control of mix proportion: During the mixing process, the mix proportion required by the construction requirements shall be strictly followed and shall not be changed arbitrarily; the same bag of premix must be mixed at one time and shall not be mixed in separate trays. Before mixing, the weighing system shall be calibrated; (3) The stirring time should be in accordance with the time required in the pre-test; (4) The first batch of material to be mixed should be tested for parameters such as slump and spread. Only after it passes the test can subsequent mixing be carried out. (5) During the mixing process, the operator should maintain constant contact with the site to confirm whether the mixture is clumping or not. If any problems are found, the cause should be investigated promptly, and the machine should be stopped for further investigation if necessary. S5: Expansion Joint UHPC Laying: Before material unloading, a dedicated coordinator instructs the concrete transport equipment to perform enhanced mixing operations (duration ≥ 5 minutes) to ensure that the steel fibers are evenly distributed in the UHPC matrix; loading equipment is used to lay UHPC instead of manual laying, avoiding trampling and disturbing the leveled concrete surface, and ensuring the surface density and flatness; before pouring, a polymer isolation membrane is laid on both sides of the expansion joint to prevent UHPC slurry from polluting the existing road surface; S6: Vibration leveling of UHPC expansion joints: UHPC pouring and vibration processes are carried out simultaneously. Vibration and leveling are performed using a high-frequency vibratory leveling machine. Before vibration leveling, the vibratory leveling machine needs to be leveled to ensure the thickness of the UHPC material. For locations where the plane elevation needs to be adjusted, material can be added or reduced manually, and the elevation can be adjusted by vibration using a plate vibrator and a handheld vibrator, as well as by manual smoothing. The distance between the vibratory rod and the side wall of the structure is controlled within the range of 50-100 mm, and the single vibration point movement distance is ≤500 mm. The vibration process is kept at a uniform speed, continuous and uninterrupted to eliminate the risk of internal air bubbles and delamination. S7: The plastering application of UHPC shall comply with the following regulations: (1) For areas with localized water shortage, water should be sprayed first, and then the surface should be smoothed. Watering should be done by spraying, and direct spraying should not be applied to the UHPC surface; (2) During the finishing process, clumps or other debris in the UHPC should be removed; (3) When smoothing the surface, if any areas are found that have not been properly vibrated, they should be vibrated and leveled in time.

[0055] S8: UHPC curing: Through curing, UHPC undergoes a full chemical reaction, significantly reducing its later shrinkage and deformation; creating favorable conditions for achieving the density, high strength, and high toughness of UHPC; Moisturizing and maintenance should be carried out immediately after UHPC paving. Every 2m-3m of UHPC paving along the bridge direction, a water-saving moisturizing film should be immediately covered for moisturizing and maintenance. The moisturizing and maintenance process is as follows: high-pressure water gun spraying - covering water-saving moisturizing film - watering for moisturizing. UHPC moisture retention maintenance uses a water-saving moisture-retaining film, which is applied using an intelligent automatic film-laying machine, achieving rapid film application, labor savings, and effective wind protection. The following requirements must be followed during UHPC moisture retention maintenance; (1) UHPC surface inspection: Before lamination, the UHPC surface is smoothed and the surface is checked for cracks. If cracks are found, they should be wiped off with water in time. (2) Spraying water before film covering: Before film covering, the UHPC surface should be sprayed with water using a high-pressure water gun; the water should be sprayed in the form of a spray, and the nozzle of the high-pressure water gun should be facing upwards, and the UHPC surface should not be sprayed directly. (3) Before laminating, carefully observe the markings on the film. The markings for the bottom layer should face down and the direction should not be reversed. (4) The width of the moisturizing film is 2m, and the length direction requires that both ends extend 20cm beyond the working surface, and the two ends are pressed firmly with wooden boards; (5) During the membrane laying process, the membrane should be smoothed with a broom to ensure that the membrane adheres tightly to the UHPC surface and there are no bubbles. If there are any bulges, they should be punctured with a wire and the exposed areas should be covered with a moisture-retaining film. (6) The overlap length between membranes is 20cm. The overlap position is pressed with a 50cm long wooden board with a spacing of 1.5m. When laying the wooden board, both ends should be level and placed gently to prevent damage to the UHPC surface. The longitudinal bridge should be neatly arranged. (7) During the moisturizing and curing process, a designated person shall conduct inspections and replenish water in a timely manner if local water shortage is found. The moisturizing and curing time for UHPC concrete shall not be less than 48 hours.

[0056] The present invention will be further illustrated below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0057] Example 1 A high-performance concrete material, the components and their mass fractions are shown in Table 1.

[0058] The silicate cement is grade 52.5 ordinary silicate cement with an average specific surface area of ​​348 m². 2 / kg, standard consistency water requirement is 27.6%, average loss on ignition is 3.85%, initial setting time is 158min, final setting time is 208min, 3-day flexural strength is 5.3MPa, and 3-day compressive strength is 28.2MPa; The mineral powder is made by grinding blast furnace steelmaking by-products (slag), and its main components are calcium silicate and calcium aluminosilicate; the particle size of the mineral powder is below 45μm, and the specific surface area of ​​the mineral powder is 500m². 2 / kg, the bulk density of the mineral powder is 1200 kg / m³ 3 ; The fly ash is Class I fly ash, with a particle size not exceeding 80μm; The silica fume is a semi-densified silica fume, dark gray in color, with a SiO2 content of 92.5%, an average loss on ignition of 2.8%, an average moisture content of 1.3%, and a water requirement ratio of 114%. The copper-plated short-end hook steel fiber has a length of 13mm and a diameter of 0.25mm; the tensile strength of the copper-plated short-end hook steel fiber is ≥2800MPa. The selected quartz sand has a particle size of 630μm-830μm, a particle size of 212μm-630μm, and a particle size of 125μm-187.5μm, and the mud content is ≤0.5%.

[0059] Table 1

[0060] Comparative Example 1 The only difference between this comparative example and Example 1 is that the concrete components do not contain mineral powder, and are supplemented with an equal amount of silicate cement. The remaining components and their mass fractions are the same as in Example 1.

[0061] Compared with Example 1, the drawbacks of this comparative example are that the concrete has less fluidity, increased cost, reduced durability, and reduced later strength.

[0062] Comparative Example 2 The only difference between this comparative example and Example 1 is that the concrete component does not contain copper-plated short-end hook steel fibers. The remaining components and their mass fractions are the same as in Example 1.

[0063] Compared with Example 1, the drawback of this comparative example is that the concrete toughness is reduced, the brittleness is increased, the fatigue resistance is reduced, the bending performance is significantly reduced, and it is more prone to cracking.

[0064] Comparative Example 3 The only difference between this comparative example and Example 1 is that the concrete component does not contain nano-silica, and is supplemented with an equal amount of silicate cement. The remaining components and their mass fractions are the same as in Example 1.

[0065] Compared with Example 1, the drawback of this comparative example is that the early strength of the concrete is reduced, and the impermeability and durability are also reduced.

[0066] Comparative Example 4 The only difference between this comparative example and Example 1 is that the concrete components do not contain BEFORM quick-setting agent. The remaining components and their mass fractions are the same as in Example 1.

[0067] Compared with Example 1, the drawback of this comparative example is that the concrete fluidity is slightly reduced and the early strength is significantly reduced.

[0068] Comparative Example 5 The only difference between this comparative example and Example 1 is that the BEFORM quick-setting agent is replaced in an equal amount with sulfoaluminate cement in the concrete components. The remaining components and their mass fractions are the same as in Example 1.

[0069] Compared with Example 1, the drawback of this comparative example is that the flexural strength of the concrete will shrink in the later stage.

[0070] Test case The performance of the concrete materials obtained in each embodiment and comparative example was tested, and the results are shown in Table 2.

[0071] Table 2

[0072] Therefore, it can be seen that, with the synergistic effect of each component and its mass ratio, the ultra-high performance concrete material of the present invention is suitable for repairing bridge expansion joints, has good compatibility, and can effectively bond with expansion joints to form an integral maintenance-free expansion joint system. It can effectively improve the crack resistance and durability of expansion joint concrete, significantly improve its mechanical properties, and play a positive role in promoting the normal use of bridge structures.

[0073] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-high performance concrete material, characterized in that, Includes the following components: Silicate cement, mineral powder, fly ash, silica fume, copper-plated short-end hook steel fiber, quartz sand, admixtures, silica, BEFORM rapid hardening agent, and water.

2. The ultra-high performance concrete material according to claim 1, characterized in that, The silicate cement includes 52.5 grade ordinary silicate cement.

3. The ultra-high performance concrete material according to claim 2, characterized in that, The mineral powder comprises calcium silicate and calcium aluminosilicate; Preferably, the particle size of the mineral powder is below 45 μm; Preferably, the specific surface area of ​​the mineral powder is 400 m². 2 / kg-600m 2 / kg, with a bulk density of 1050kg / m³ 3 -1375kg / m 3 .

4. The ultra-high performance concrete material according to any one of claims 1-3, characterized in that, The fly ash includes Class I fly ash; Preferably, the particle size of the fly ash is not greater than 80 μm; Preferably, the silica fume comprises semi-densified silica fume.

5. The ultra-high performance concrete material according to claim 4, characterized in that, The copper-plated short-end hook steel fiber has a length of 10mm-30mm and a diameter of 0.2mm-0.3mm; Preferably, the tensile strength of the copper-plated short-end hook steel fiber is ≥2800MPa.

6. The ultra-high performance concrete material according to claim 5, characterized in that, The quartz sand includes at least one of the following: quartz sand with a particle size of 630μm-830μm, quartz sand with a particle size of 212μm-630μm, and quartz sand with a particle size of 125μm-187.5μm. Preferably, the silicon dioxide comprises nano-silicon dioxide; Preferably, the admixture includes a water-reducing agent; Preferably, the water-reducing agent includes a polycarboxylate water-reducing agent.

7. The ultra-high performance concrete material according to claim 6, characterized in that, The ultra-high performance concrete material comprises the following components by weight: 780-830 parts silicate cement, 1-50 parts mineral powder, 84-124 parts fly ash, 140-180 parts silica fume, 120-180 parts copper-plated short-end hook steel fiber, 908-1118 parts quartz sand, 26-36 parts polycarboxylate superplasticizer, 10-30 parts nano silica, 30-70 parts BEFORM rapid hardening agent, and 170-190 parts water.

8. The application of the ultra-high performance concrete material according to any one of claims 1-7 in bridge maintenance.

9. The application according to claim 8, characterized in that, The bridge maintenance includes the maintenance of bridge expansion joints.

10. A construction method for the ultra-high performance concrete material according to any one of claims 1-7, characterized in that, Includes the following steps: The ultra-high performance concrete material is poured using an alternating layered pouring technique and cured using a temperature gradient curing technique. Preferably, an alternating layered pouring technique is used: the layer thickness is controlled between 300mm and 500mm, a portion is poured first, and then adjacent or symmetrical portions are poured, alternating between the two, and the interval between pouring adjacent layers or adjacent blocks does not exceed the initial setting time of the concrete. Preferably, temperature gradient curing technology is used for curing: the curing process is divided into heating, constant temperature and cooling; wherein, the heating rate is not greater than 12℃ / h, the cooling rate is not greater than 15℃ / h, the constant temperature is controlled at 80±5℃, and the constant temperature curing time is not less than 48 hours; when the insulation facilities are removed, the difference between the surface temperature of the component and the ambient temperature does not exceed 20℃.

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