A fiber-reinforced modified coarse aggregate and its marine ultra-high performance concrete material and application

Abstract

The present invention relates to the technical field of marine concrete preparation, and specifically discloses a fiber-reinforced modified coarse aggregate and its marine ultra-high performance concrete material and application. The concrete material comprises the following components: 495 to 688 parts by weight of cement binder, 200 to 800 parts by weight of the fiber-reinforced modified coarse aggregate of the present invention, 22 to 138 parts by weight of modified rubber particles, 142 to 197 parts by weight of fly ash, 71 to 98 parts by weight of silica fume, 708 to 983 parts by weight of quartz sand, 78 to 157 parts by weight of reinforcing fiber, 14 to 20 parts by weight of water reducer, and 113 to 160 parts by weight of water. The ultra-high performance concrete material of the present invention is added with fiber-reinforced modified coarse aggregate and modified rubber particles, so that the concrete material prepared by the present invention has high strength, high impact and abrasion resistance, and crack resistance, thereby better adapting to service in marine environments.

Description

Technical Field

[0001] The present invention relates to the technical field of marine engineering concrete preparation, and in particular to a fiber-reinforced modified coarse aggregate and a marine engineering ultra-high performance concrete material and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] With nearly 40 years of large-scale port construction, my country has accumulated extensive port construction experience and advanced technologies. Concrete is the primary building material for coastal port structures. However, concrete structures in ports are subject not only to marine environmental factors such as fluctuating temperatures and humidity, and chloride ion corrosion, but also to unstable wind and wave loads, berthing ship loads, accumulated cargo loads, and vehicle loads. Traditional concrete, due to its insufficient strength, crack resistance, and durability, struggles to meet the unique demands of service in complex marine environments.

[0004] Ultra-high-performance concrete (UHPC) is gaining widespread application in specialized engineering applications. UHPC utilizes fine, stable quartz sand as an aggregate and a variety of mineral admixtures, such as cement, fly ash, and silica fume, as binders. These binders comprise a significant portion of the UHPC system by volume. Furthermore, UHPC's extremely low water-to-binder ratio and the efficient filling of its mineral admixtures result in a significantly denser internal structure than conventional concrete. Consequently, UHPC boasts excellent overall performance, with strength reaching 3 to 16 times that of conventional concrete. Furthermore, the incorporation of external fiber materials mitigates concrete's inherent shortcomings, such as poor toughness, crack resistance, and low tensile strength. UHPC's ductility and energy absorption capacity are typically 300 times that of conventional concrete. However, UHPC exhibits insufficient abrasion resistance under dynamic loads, making it particularly susceptible to surface spalling in marine environments. Therefore, improving UHPC's wear resistance is crucial for further promoting its application in marine engineering. Summary of the Invention

[0005] The present invention provides a fiber-reinforced modified coarse aggregate and its marine ultra-high performance concrete material and application. By incorporating fiber-reinforced modified coarse aggregate and modified rubber particles, the resulting concrete material possesses high strength, high abrasion resistance, and crack resistance, making it better suited for service in marine environments. Specifically, the technical solution of the present invention is as follows.

[0006] First, the present invention provides a fiber-reinforced modified coarse aggregate, which is obtained by the following steps:

[0007] (1) The rock coarse aggregate is placed in a rotating drum sand blasting chamber, and then the rolling rock coarse aggregate is processed by using steel sand ejected from its nozzle. After separating and removing the steel sand, the modified coarse aggregate is obtained and set aside.

[0008] (2) A matrix-type melting lattice is formed on the surface of the modified coarse aggregate using a laser beam in an inert gas atmosphere, and then steel fibers are inserted into the melting points of the melting lattice. After cooling, fiber-reinforced coarse aggregate is obtained.

[0009] (3) Soaking the fiber-reinforced coarse aggregate in a silicate solution, separating the fiber-reinforced coarse aggregate after completion, drying it, and then placing it in ethanol containing a silane coupling agent for standing, separating the coarse aggregate after completion, and obtaining the fiber-reinforced modified coarse aggregate after drying.

[0010] Furthermore, in step (1), the particle size of the rock coarse aggregate is 5-10 mm.

[0011] Furthermore, in step (1), the fineness of the steel grit is 80-120 mesh, and the injection speed is 220-250 m / s. Optionally, the distance between the nozzle and the surface of the coarse aggregate is 15-30 cm, and the inclination angle relative to the aggregate is 45-75°.

[0012] Furthermore, in step (1), the rotation speed of the rotary drum sandblasting chamber is 4-10 r / min.

[0013] Furthermore, in step (1), the surface treatment is performed until the surface roughness of the coarse aggregate reaches Ra=15~25μm.

[0014] Furthermore, in step (2), the distance between adjacent melting points in the melting point lattice is 2 to 4 mm. Optionally, the inert gas includes any one of helium, argon, nitrogen, etc.

[0015] Furthermore, in step (2), the melting depth of the melting point is 3±0.2 mm. Optionally, the wavelength of the laser beam is 1000~1200 nm, and the power is 1.5~2.5 kW / cm 2 , the spot diameter is 1.2~1.8 mm, and the scanning speed is 1~1.5m / min.

[0016] Furthermore, in step (2), the length of the steel fiber is 8-14 mm, and the diameter is 0.18-0.22 mm.

[0017] Furthermore, in step (3), the ratio of the fiber-reinforced coarse aggregate to the silicate solution is 1g:10-20ml. Optionally, the mass fraction of the silicate solution is 5-11%. The silicate includes at least one of sodium silicate, potassium silicate, etc.

[0018] Furthermore, in step (3), the soaking and standing times are both 20 to 30 minutes.

[0019] Furthermore, in step (3), the ratio of the fiber-reinforced coarse aggregate to the ethanol containing the silane coupling agent is 1 g: 5-12 ml. Optionally, the mass fraction of the silane coupling agent in the ethanol is 4-8%. The silane coupling agent includes at least one of KH550, KH560, KH570, etc.

[0020] Secondly, the present invention provides a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following components: 495 to 688 parts by weight of cement binder, 200 to 800 parts by weight of the fiber-reinforced modified coarse aggregate of the present invention, 22 to 138 parts by weight of rubber particles, 142 to 197 parts by weight of fly ash, 71 to 98 parts by weight of silica fume, 708 to 983 parts by weight of quartz sand, 78 to 157 parts by weight of reinforcing fiber, 14 to 20 parts by weight of water reducer, and 113 to 160 parts by weight of water.

[0021] Furthermore, the reinforcing fiber comprises at least one of steel fiber, plastic fiber, carbon fiber, etc. Optionally, the reinforcing fiber has a length of 8 to 20 mm and a diameter of 0.18 to 0.22 mm.

[0022] Furthermore, the fineness of the quartz sand and rubber particles is 20-40 mesh.

[0023] Furthermore, the water reducer includes at least one of a polycarboxylate water reducer, a naphthalene-based water reducer, a lignin sulfonate water reducer, and the like.

[0024] Furthermore, the rubber particles are modified rubber particles treated by the following method: the rubber particles are surface treated using a plasma formed by a mixture of ammonia and oxygen. The resulting modified rubber particles are then mixed with a modification solution consisting of butyl acrylate, hydroxyethyl methacrylate, nano-silica, and water. Ammonium persulfate and sodium bisulfite are then added and a graft copolymerization reaction is carried out under heating. After completion, the particles are separated, washed, and dried to obtain the modified rubber particles.

[0025] Furthermore, the volume ratio of ammonia to oxygen is 2.5 to 4:1. Optionally, the surface treatment time is 5 to 30 minutes. During this process, the plasma forms amino (-NH2) and hydroxyl (-OH) active sites on the surface of the rubber particles, while simultaneously etching the surface of the rubber particles to increase roughness.

[0026] Furthermore, the mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silica, water, ammonium persulfate, and sodium bisulfite is 100-110: 3-6: 11-20g: 0.4-0.75: 115-130: 1.5-2.2: 1.5-2.2. Optionally, the ammonium persulfate and sodium bisulfite are added as aqueous solutions with a mass fraction of 3-4.5%.

[0027] Furthermore, the heating temperature is 55-65° C., and the graft copolymerization reaction time is 2-3 hours.

[0028] The particles are then washed with at least one of methanol and ethanol and then vacuum-dried at 50-70°C for 10-12 hours to obtain the modified rubber particles. During this process, amino- and hydroxyl-containing monomers (i.e., butyl acrylate and hydroxyethyl methacrylate) are grafted onto the surface of the rubber particles using the active sites as anchors, thereby improving the bonding between the rubber particles and the concrete matrix. Simultaneously, the nano-silica adheres to the surface of the rubber particles, increasing their hardness and strength.

[0029] Finally, the present invention discloses the application of the high-strength and high-wear-resistant marine engineering ultra-high performance concrete material in the fields of construction engineering, marine engineering, bridge engineering, road engineering, water conservancy and hydropower engineering, etc.

[0030] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0031] (1) The ultra-high performance concrete material of the present invention is added with fiber-reinforced modified coarse aggregate, which significantly improves the mechanical strength, crack resistance and wear resistance of the concrete material prepared by the present invention. This is because: the present invention first uses steel sand to impact the surface of the rock coarse aggregate, and uses the pits formed to significantly increase the roughness of the coarse aggregate surface, thereby increasing the contact area between the coarse aggregate and the concrete material matrix, improving the bonding force between the two, and improving the strength and crack resistance of the concrete material. Furthermore, the present invention also uses a laser beam to form a matrix melting point array on the surface of the modified coarse aggregate obtained by the above treatment, and then inserts steel fibers into the melting point. In this way, after cooling, the melting point re-solidifies and hardens, and one end of the steel fiber can be firmly fixed to the coarse aggregate, forming a structure with steel fibers anchored on the surface. After being incorporated into the concrete material, the steel fibers can be used to form a mechanical interlocking effect between the coarse aggregate and the concrete matrix, so that when subjected to external loads, a linkage effect is formed between the coarse aggregate, the steel fibers and the concrete matrix, significantly enhancing the mechanical strength of the concrete material. At the same time, the mechanical interlocking effect effectively prevents the concrete structure from peeling when subjected to external scouring, thereby improving its abrasion resistance and enhancing the durability of the concrete material when used in marine environments. Furthermore, the interlocking effect significantly suppresses cracks caused by volume shrinkage during the concrete hardening process, preventing the resulting decrease in the concrete's mechanical strength.

[0032] (2) The present invention further modifies the coarse aggregate using a silicate solution and a silane coupling agent. The silicate can form a thin film on the surface of the coarse aggregate to increase the bonding strength between the aggregate and the matrix. At the same time, the silicate can excite the glass structure formed after the molten lattice is cooled, destroying the silicon-oxygen covalent bond and the aluminum-oxygen covalent bond, causing the silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron in the glass to depolymerize and form Al(OH) 4- 、Al(OH)6 3- 、Si(OH) 3- 、SiO2(OH)2 2- The plasma monomers react with the hydration product calcium hydroxide to form hydrated calcium silicate and hydrated calcium aluminate, enhancing the hardening strength of the cement and further improving the anchoring effect on the steel fibers, thereby increasing the mechanical strength of the concrete material. The silane coupling agent can penetrate into the coarse aggregate, improving the bonding between the aggregate and the concrete matrix, and increasing the strength of the concrete.

[0033] (3) The ultra-high performance concrete material of the present invention also adds rubber particles, which greatly improves the elasticity and toughness of the concrete material, thereby further improving the impact resistance of the concrete material. This is because when the concrete structure is impacted by water flow, the rubber particles absorb part of the energy through their own deformation and slow down the propagation of the impact force, thereby reducing the generation and development of cracks on the surface of the matrix. At the same time, by modifying the surface of the rubber particles, the affinity and bonding between the rubber particles and the concrete matrix are also ensured, reducing the adverse effects on the mechanical strength of the concrete. To this end, the present invention first uses a plasma formed by a mixed gas of ammonia and oxygen to treat the rubber particles on the surface, thereby forming amino (-NH2) and hydroxyl (-OH) active sites on the surface of the rubber particles. These active sites have good affinity with the concrete matrix, thereby effectively enhancing the interfacial bonding between the two, reducing defects in the interface transition zone, and improving the resistance to chloride ion penetration. At the same time, the above-mentioned treatment of the surface of the rubber particles will also increase the surface roughness, thereby increasing the contact area between the rubber particles and the concrete matrix, thereby helping to improve the bonding between the two and reducing the adverse effects of the addition of rubber particles on the mechanical strength of the concrete. Furthermore, the present invention also uses the active sites as anchor points to graft the amino-containing monomer butyl acrylate and the hydroxyl-containing monomer hydroxyethyl methacrylate onto the surface of the rubber particles, forming a chemical bonding layer through free radical polymerization to improve the bonding force between the rubber particles and the concrete matrix. At the same time, nano-silica is attached to the surface of the rubber particles, thereby improving the hardness and strength of the rubber particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0035] Figure 1 This is a compressive strength test diagram of the following Example 1.

[0036] Figure 2 This is a graph showing the splitting tensile strength test of Example 1 below.

[0037] Figure 3 This is a graph showing the abrasion resistance test of Example 1 below.

[0038] Figure 4 This is a test diagram of the chloride ion diffusion coefficient of the following Example 1.

[0039] Figure 5 This is a graph showing the abrasion resistance test of Example 2 below.

[0040] Figure 6 This is a graph showing the abrasion resistance test of Example 3 below.

[0041] Figure 7 This is a graph showing the abrasion resistance test of Example 4 below.

[0042] Figure 8 This is a graph showing the abrasion resistance test of Example 5 below.

[0043] Figure 9 This is a graph showing the abrasion resistance test of Example 6 below.

[0044] Figure 10 This is a graph showing the abrasion resistance test of Example 7 below.

[0045] Figure 11 This is a graph showing the abrasion resistance test of Example 8 below. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0047] Unless otherwise defined, all professional and scientific terms used in the present invention have the same meanings as those familiar to those skilled in the art. The reagents and raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents and raw materials used in the present invention are used in accordance with conventional methods in the art or in accordance with the product instructions.

[0048] In addition, any methods and materials similar or equivalent to those described herein can be applied to the method of the present invention. The technical solution of the present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps:

[0051] (1) Granite crushed stone coarse aggregate with a particle size distribution between 5 and 7 mm was washed with water and air-dried, and then placed in a rotating drum sandblasting chamber with a rotation speed of 5 r / min. Then, an air compression system was used to drive 100-mesh steel sand to be ejected from the multi-directional array nozzle of the rotating drum sandblasting chamber to impact the surface of the coarse aggregate. The distance between the nozzle and the coarse aggregate surface was set to 20 cm, the inclination angle relative to the coarse aggregate was set to 60°, the nozzle diameter was 10 mm, and the steel sand speed was 220 m / s. At the same time, a laser profilometer was used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reached 15 μm, the treatment was stopped. Then, a high-pressure cyclone with an air pressure of 0.3 MPa was used to remove the residual steel sand in the coarse aggregate, thereby obtaining the modified coarse aggregate for later use.

[0052] (2) The laser beam emitted by the fiber laser (wavelength set to 1064nm, power 1.8kW / cm 2 A three-dimensional dynamic focusing system (with a spot diameter of 1.5 mm and a scanning speed of 1 m / min) was used to form a matrix of melting points with a melting depth of 3 ± 0.2 mm on the surface of the modified coarse aggregate, with the spacing between adjacent melting points set at 3 mm. A six-axis robotic arm equipped with an electromagnetic positioning fixture then secured the modified coarse aggregate. Steel fibers with a length of 10 mm and a diameter of 0.2 mm were inserted into the melting points. The modified coarse aggregate was then cooled to room temperature to obtain the fiber-reinforced coarse aggregate, which was then set aside.

[0053] (3) The fiber-reinforced coarse aggregate was mixed with a sodium silicate solution having a mass fraction of 7% at a ratio of 1 g:15 ml and then soaked for 25 minutes. After completion, the fiber-reinforced coarse aggregate was filtered out and dried at 80°C. Then, it was mixed with ethanol containing 5 wt.% of a silane coupling agent (KH550) at a ratio of 1 g:10 ml and allowed to stand for 25 minutes. After completion, the coarse aggregate was filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for later use.

[0054] 2. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps:

[0055] (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 560 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 600 parts by weight of 40-mesh rubber particles, 120 parts by weight of Class I fly ash, 160 parts by weight of silica fume (specific surface area of 16880 m 2 / kg), 80 parts by weight of quartz sand (40 mesh), 870 parts by weight of quartz sand (40 mesh), 130 parts by weight of hook-end copper-coated steel fiber (length 14 mm, diameter 0.22 mm), 17 parts by weight of polycarboxylate water-reducing agent (water-reducing rate 30.6%), and 140 parts by weight of water.

[0056] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume, and quartz sand are mixed and stirred for 2 minutes. The water and water reducer are then added and stirred for 5 minutes to obtain a slurry. The steel fibers are then poured into a 0.5 mm mesh sieve, and the mesh sieve is shaken to evenly disperse the steel fibers into the stirring slurry. The mixture is stirred for 8 minutes to obtain an ultra-high performance concrete material.

[0057] Performance test: According to the "Ultra-High Performance Concrete Test Method Standard" (T / CECS 864-2021), "Hydraulic Concrete Test Procedure" (DL / T 5150-2001), "Concrete Long-term Performance and Durability Test Method Standard" (GBT50082-2024), the compressive strength, splitting tensile strength, abrasion resistance, and chloride ion diffusion coefficient of the specimens prepared from the ultra-high performance concrete material of this embodiment (standard curing, age 28 days) were tested (respectively as follows Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 The results are shown in the following table:

[0058] .

[0059] Example 2

[0060] 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps:

[0061] (1) Granite crushed stone coarse aggregate with a particle size distribution between 8 and 10 mm was washed with water and air-dried, and then placed in a rotating drum sandblasting chamber with a rotation speed of 10 r / min. Then, an air compression system was used to drive 80-mesh steel sand to be ejected from the multi-directional array nozzle of the rotating drum sandblasting chamber to impact the surface of the coarse aggregate. The distance between the nozzle and the coarse aggregate surface was set to 30 cm, the inclination angle relative to the coarse aggregate was set to 45°, the nozzle diameter was 10 mm, and the steel sand speed was 240 m / s. At the same time, a laser profilometer was used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reached 20 μm, the treatment was stopped. Then, a high-pressure cyclone with an air pressure of 0.3 MPa was used to remove the residual steel sand in the coarse aggregate, thereby obtaining the modified coarse aggregate for later use.

[0062] (2) The laser beam emitted by the fiber laser (wavelength set to 1200nm, power set to 1.5kW / cm 2 A three-dimensional dynamic focusing system (with a spot diameter of 1.2 mm and a scanning speed of 1.3 m / min) was used to form a matrix of melting points with a melt depth of 3 ± 0.2 mm on the surface of the modified coarse aggregate, with the spacing between adjacent melting points set at 2 mm. A six-axis robotic arm equipped with an electromagnetic positioning fixture then secured the modified coarse aggregate. Steel fibers with a length of 8 mm and a diameter of 0.18 mm were inserted into the melting points. The modified coarse aggregate was then cooled to room temperature to obtain the fiber-reinforced coarse aggregate, which was then set aside.

[0063] (3) The fiber-reinforced coarse aggregate was mixed with a sodium silicate solution having a mass fraction of 5% at a ratio of 1 g:20 ml and then soaked for 20 minutes. After completion, the fiber-reinforced coarse aggregate was filtered out and dried at 80°C. Then, it was mixed with ethanol containing 4 wt.% of a silane coupling agent (KH570) at a ratio of 1 g:12 ml and allowed to stand for 30 minutes. After completion, the coarse aggregate was filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for later use.

[0064] 2. A method for preparing modified rubber particles, comprising the following steps:

[0065] (I) A radio frequency glow discharge plasma reactor (power setting 200 W) was used to generate a low-temperature plasma from a mixture of ammonia and oxygen (volume ratio 2.5:1). Argon gas at 100 Pa was then injected into the plasma to treat 20-mesh rubber particles for 30 min.

[0066] (II) The modified rubber particles obtained were mixed with a modification solution consisting of butyl acrylate, hydroxyethyl methacrylate, nano-silica, and water, and stirred for 15 minutes. Ammonium persulfate and sodium bisulfite were then added, and the mixture was heated in a water bath to 55° C. for reaction for 3 hours. The mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silica, water, ammonium persulfate, and sodium bisulfite was 100:3:11 g:0.4:130:1.5:1.5, and the ammonium persulfate and sodium bisulfite were each added dropwise in a 3% by mass aqueous solution over a period of 1 hour. After completion, the particles were filtered, washed three times with ethanol, and then vacuum-dried at 70° C. for 10 hours to obtain the modified rubber particles, which were then set aside.

[0067] 3. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps:

[0068] (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 688 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 800 parts by weight of the modified rubber particles of this embodiment, 138 parts by weight of Class I fly ash, 197 parts by weight of silica fume (specific surface area of 16880m 2 / kg), 98 parts by weight of quartz sand (20 mesh), 983 parts by weight of quartz sand (20 mesh), 157 parts by weight of hook-end copper-coated steel fiber (length 8 mm, diameter 0.22 mm), 20 parts by weight of polycarboxylate water-reducing agent (water-reducing rate 30.6%), and 160 parts by weight of water.

[0069] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume, and quartz sand are mixed and stirred for 2 minutes. The water and water reducer are then added and stirred for 5 minutes to obtain a slurry. The steel fibers are then poured into a 0.5 mm mesh sieve, and the mesh sieve is shaken to evenly disperse the steel fibers into the stirring slurry. The mixture is stirred for 8 minutes to obtain an ultra-high performance concrete material.

[0070] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 5 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0071] .

[0072] Example 3

[0073] 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps:

[0074] (1) Granite crushed stone coarse aggregate with a particle size distribution between 6 and 8 mm was washed with water and air-dried, and then placed in a rotating drum sandblasting chamber with a rotation speed of 4 r / min. Then, an air compression system was used to drive 120-mesh steel sand to be ejected from the multi-directional array nozzle of the rotating drum sandblasting chamber to impact the surface of the coarse aggregate. The distance between the nozzle and the coarse aggregate surface was set to 15 cm, the inclination angle relative to the coarse aggregate was set to 75°, the nozzle diameter was 10 mm, and the steel sand speed was 250 m / s. At the same time, a laser profilometer was used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reached 25 μm, the treatment was stopped. Then, a high-pressure cyclone with an air pressure of 0.3 MPa was used to remove the residual steel sand in the coarse aggregate, thereby obtaining the modified coarse aggregate for later use.

[0075] (2) The laser beam emitted by the fiber laser (wavelength set to 1000nm, power set to 2.5kW / cm 2 A three-dimensional dynamic focusing system (with a spot diameter of 1.8 mm and a scanning speed of 1.5 m / min) was used to form a matrix of melting points with a melt depth of 3 ± 0.2 mm on the surface of the modified coarse aggregate, with the spacing between adjacent melting points set at 4 mm. A six-axis robotic arm equipped with an electromagnetic positioning fixture then secured the modified coarse aggregate. Steel fibers with a length of 14 mm and a diameter of 0.22 mm were inserted into the melting points. The modified coarse aggregate was then cooled to room temperature to obtain the fiber-reinforced coarse aggregate, which was then set aside.

[0076] (3) The fiber-reinforced coarse aggregate was mixed with a potassium silicate solution having a mass fraction of 11% at a ratio of 1 g:10 ml and then soaked for 30 minutes. After completion, the fiber-reinforced coarse aggregate was filtered out and dried at 80°C. Then, it was mixed with ethanol containing 8 wt.% of a silane coupling agent (KH560) at a ratio of 1 g:4 ml and allowed to stand for 25 minutes. After completion, the coarse aggregate was filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for later use.

[0077] 2. A method for preparing modified rubber particles, comprising the following steps:

[0078] (I) A radio frequency glow discharge plasma reactor (power setting is 100 W) was used to generate a low-temperature plasma from a mixture of ammonia and oxygen (volume ratio 4:1). Argon gas at 80 Pa was then injected into the plasma to treat 30-mesh rubber particles for 5 min.

[0079] (II) The modified rubber particles obtained were mixed with a modification solution consisting of butyl acrylate, hydroxyethyl methacrylate, nano-silica, and water, and stirred for 15 minutes. Ammonium persulfate and sodium bisulfite were then added, and the mixture was heated in a water bath to 65° C. for reaction for 2 hours. The mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silica, water, ammonium persulfate, and sodium bisulfite was 110:6:20 g:0.75:115:2.2:2.2, and the ammonium persulfate and sodium bisulfite were each added dropwise in the form of a 4.5% by mass aqueous solution over a period of 1 hour. After completion, the particles were filtered, washed three times with ethanol, and then vacuum-dried at 50° C. for 12 hours to obtain the modified rubber particles, which were then set aside.

[0080] 3. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps:

[0081] (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 495 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 200 parts by weight of the modified rubber particles of this embodiment, 22 parts by weight of Class I fly ash, 142 parts by weight of silica fume (specific surface area of 16880m 2 / kg), 71 parts by weight of quartz sand (40 mesh), 708 parts by weight of quartz sand with 40 mesh, 78 parts by weight of hook-end copper-coated steel fiber (length 20 mm, diameter 0.18 mm), 14 parts by weight of polycarboxylate water-reducing agent (water-reducing rate 30.6%), and 113 parts by weight of water.

[0082] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume, and quartz sand are mixed and stirred for 2 minutes. The water and water reducer are then added and stirred for 5 minutes to obtain a slurry. The steel fibers are then poured into a 0.5 mm mesh sieve, and the mesh sieve is shaken to evenly disperse the steel fibers into the stirring slurry. The mixture is stirred for 8 minutes to obtain an ultra-high performance concrete material.

[0083] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 6 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0084] .

[0085] Example 4

[0086] A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material is different from the above-mentioned embodiment 1 in that the present embodiment adopts the following steps to prepare reinforced modified coarse aggregate instead of the fiber-reinforced modified coarse aggregate of embodiment 1:

[0087] (1) Granite crushed stone coarse aggregate with a particle size distribution between 5 and 7 mm was washed with water and air-dried, and then placed in a rotating drum sandblasting chamber with a rotation speed of 5 r / min. Then, an air compression system was used to drive 100-mesh steel sand to be ejected from the multi-directional array nozzle of the rotating drum sandblasting chamber to impact the surface of the coarse aggregate. The distance between the nozzle and the coarse aggregate surface was set to 20 cm, the inclination angle relative to the coarse aggregate was set to 60°, the nozzle diameter was 10 mm, and the steel sand speed was 220 m / s. At the same time, a laser profilometer was used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reached 15 μm, the treatment was stopped. Then, a high-pressure cyclone with an air pressure of 0.3 MPa was used to remove the residual steel sand in the coarse aggregate, thereby obtaining the modified coarse aggregate for later use.

[0088] (2) The modified coarse aggregate was mixed with a sodium silicate solution having a mass fraction of 7% at a ratio of 1 g:15 ml and then soaked for 25 minutes. After completion, the modified coarse aggregate was filtered out and dried at 80°C. Then, the modified coarse aggregate was mixed with ethanol containing 5 wt.% of a silane coupling agent (KH550) at a ratio of 1 g:10 ml and allowed to stand for 25 minutes. After completion, the coarse aggregate was filtered out and dried at 60°C to obtain the reinforced modified coarse aggregate.

[0089] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 7 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0090] .

[0091] Example 5

[0092] A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material is different from the above-mentioned embodiment 2 in that the fiber-reinforced modified coarse aggregate of this embodiment is obtained by the following steps:

[0093] (1) Granite crushed stone coarse aggregate with a particle size distribution between 8 and 10 mm was washed with water and air-dried. Then, a laser beam (wavelength set to 1200 nm and power set to 1.5 kW / cm2) emitted by a fiber laser was used in a helium shielding gas. 2 Using a three-dimensional dynamic focusing system (with a spot diameter of 1.2 mm and a scanning speed of 1.3 m / min), a matrix of melting points with a melting depth of 3 ± 0.2 mm was formed on the surface of the granite crushed coarse aggregate, with the spacing between adjacent melting points set at 2 mm. A six-axis robotic arm equipped with an electromagnetic positioning fixture then secured the modified coarse aggregate. Steel fibers with a length of 8 mm and a diameter of 0.18 mm were inserted into the melting points. The modified coarse aggregate was then cooled to room temperature to obtain the fiber-reinforced coarse aggregate, which was then set aside.

[0094] (2) The fiber-reinforced coarse aggregate was mixed with a sodium silicate solution having a mass fraction of 5% at a ratio of 1 g:20 ml and then soaked for 20 minutes. After completion, the fiber-reinforced coarse aggregate was filtered out and dried at 80°C. Then, it was mixed with ethanol containing 4 wt.% of a silane coupling agent (KH570) at a ratio of 1 g:12 ml and allowed to stand for 30 minutes. After completion, the coarse aggregate was filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate.

[0095] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 8 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0096] .

[0097] Example 6

[0098] A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material comprises the following steps:

[0099] (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m2 / kg), 560 parts by weight of the fiber-reinforced coarse aggregate prepared in step (2) of Example 1, 600 parts by weight of 40-mesh rubber particles, 120 parts by weight of Class I fly ash, 160 parts by weight of silica fume (specific surface area of 16880 m 2 / kg), 80 parts by weight of quartz sand (40 mesh), 870 parts by weight of quartz sand (40 mesh), 130 parts by weight of hook-end copper-coated steel fiber (length 14 mm, diameter 0.22 mm), 17 parts by weight of polycarboxylate water-reducing agent (water-reducing rate 30.6%), and 140 parts by weight of water.

[0100] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume, and quartz sand are mixed and stirred for 2 minutes. The water and water reducer are then added and stirred for 5 minutes to obtain a slurry. The steel fibers are then poured into a 0.5 mm mesh sieve, and the mesh sieve is shaken to evenly disperse the steel fibers into the stirring slurry. The mixture is stirred for 8 minutes to obtain an ultra-high performance concrete material.

[0101] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 9 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0102] .

[0103] Example 7

[0104] A method for preparing a high-strength and high-wear-resistant marine ultra-high-performance concrete material differs from the above-mentioned Example 3 in that the modified rubber particles in this example are obtained by the following steps: a mixed gas of ammonia and oxygen (volume ratio of 4:1) is formed into a low-temperature plasma using a radio frequency glow discharge plasma reactor (power set to 100 W), and then 80 Pa of argon is used to spray 30-mesh rubber particles with the plasma for surface treatment for 5 minutes to obtain the modified rubber particles.

[0105] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 10 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0106] .

[0107] Example 8

[0108] A method for preparing a high-strength, high-wear-resistant, ultra-high-performance concrete material for marine engineering applications differs from the above-described Example 2 in that the modified rubber particles of this example are prepared by mixing 20-mesh rubber particles with a modifying solution consisting of butyl acrylate, hydroxyethyl methacrylate, nano-silica, and water, followed by stirring for 15 minutes. Ammonium persulfate and sodium bisulfite are then added, followed by heating in a water bath to 55°C for 3 hours. The mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silica, water, ammonium persulfate, and sodium bisulfite is 100:3:11g:0.4:130:1.5:1.5, and the ammonium persulfate and sodium bisulfite are each added dropwise as a 3% by mass aqueous solution over 1 hour. After completion, the particles are filtered, washed three times with ethanol, and vacuum-dried at 70°C for 10 hours to obtain the modified rubber particles.

[0109] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Figure 11 The chloride ion diffusion coefficient was tested and the results are shown in the following table:

[0110] .

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A fiber-reinforced modified coarse aggregate, characterized in that: The coarse aggregate is obtained by the following steps: (1) placing rock coarse aggregate in a rotating drum sandblasting chamber, and then using steel sand ejected from its nozzle to treat the rolling rock coarse aggregate, separating and removing the steel sand to obtain modified coarse aggregate for standby use; (2) forming a matrix-type melting lattice on the surface of the modified coarse aggregate using a laser beam in an inert gas, and then inserting steel fibers into the melting points of the melting lattice, and obtaining fiber-reinforced coarse aggregate after cooling; (3) The fiber-reinforced coarse aggregate is immersed in a silicate solution, and after completion, the fiber-reinforced coarse aggregate is separated and dried, and then placed in ethanol containing a silane coupling agent for standing, and after completion, the coarse aggregate is separated and dried to obtain the fiber-reinforced modified coarse aggregate.

2. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (1), the fineness of the steel grit is 80-120 mesh, and the injection speed is 220-250 m / s.

3. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (1), the distance between the nozzle and the surface of the coarse aggregate is 15-30 cm, and the inclination angle relative to the aggregate is 45-75°.

4. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (1), the particle size of the rock coarse aggregate is 5-10 mm.

5. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (1), the surface treatment is performed until the surface roughness of the coarse aggregate reaches Ra=15~25μm.

6. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (1), the rotation speed of the rotary drum sandblasting chamber is 4-10 r / min.

7. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the distance between adjacent melting points in the melting point matrix is 2 to 4 mm.

8. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the inert gas includes any one of helium, argon, and nitrogen.

9. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the melting depth of the melting point lattice is 3±0.2 mm.

10. The fiber-reinforced modified coarse aggregate according to claim 1, wherein In step (2), the wavelength of the laser beam is 1000-1200 nm, and the power is 1.5-2.5 kW / cm 2 , the spot diameter is 1.2~1.8 mm, and the scanning speed is 1~1.5m / min.

11. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the length of the steel fiber is 8-14 mm and the diameter is 0.18-0.22 mm.

12. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (3), the ratio of the fiber-reinforced coarse aggregate to the silicate solution is 1 g: 10-20 ml.

13. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: The mass fraction of the silicate solution is 5-11%.

14. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: The silicate includes at least one of sodium silicate and potassium silicate.

15. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (3), the soaking and standing time are both 20 to 30 minutes.

16. The fiber-reinforced modified coarse aggregate according to any one of claims 1 to 15, characterized in that: In step (3), the ratio of the fiber-reinforced coarse aggregate to the ethanol containing the silane coupling agent is 1 g: 5-12 ml.

17. The fiber-reinforced modified coarse aggregate according to claim 16, characterized in that: In step (3), the mass fraction of the silane coupling agent in the ethanol is 4-8%.

18. The fiber-reinforced modified coarse aggregate according to any one of claims 1 to 15, characterized in that: In step (3), the silane coupling agent includes at least one of KH550, KH560, and KH570.

19. A high-strength and high-wear-resistant marine ultra-high performance concrete material, characterized in that: The invention comprises the following components: 495-688 parts by weight of cement binder, 200-800 parts by weight of the fiber-reinforced modified coarse aggregate according to any one of claims 1 to 18, 22-138 parts by weight of rubber particles, 142-197 parts by weight of fly ash, 71-98 parts by weight of silica fume, 708-983 parts by weight of quartz sand, 78-157 parts by weight of reinforcing fiber, 14-20 parts by weight of a water reducer, and 113-160 parts by weight of water.

20. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 19, characterized in that: The reinforcing fiber includes at least one of steel fiber, plastic fiber and carbon fiber.

21. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 19, characterized in that: The reinforcing fibers have a length of 8 to 20 mm and a diameter of 0.18 to 0.22 mm.

22. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 19, characterized in that: The fineness of the quartz sand and rubber particles is 20-40 mesh.

23. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 19, characterized in that: The water reducer includes at least one of a polycarboxylate water reducer, a naphthalene water reducer, and a lignin sulfonate water reducer.

24. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to any one of claims 19 to 23, characterized in that: The rubber particles are modified rubber particles obtained by the following treatment method: surface treatment of the rubber particles is performed using plasma formed by a mixture of ammonia and oxygen; the modified particles are then mixed with a modification solution formed by butyl acrylate, hydroxyethyl methacrylate, and nano-silicon dioxide; ammonium persulfate and sodium bisulfite are then added and a graft copolymerization reaction is performed under heating; after completion, the particles are separated, washed, and dried to obtain the modified rubber particles.

25. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The volume ratio of ammonia to oxygen is 2.5-4:

1.

26. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The surface treatment time is 5 to 30 minutes.

27. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The mass ratio of the modified particles, butyl acrylate, hydroxyethyl methacrylate, nano-silicon dioxide, water, ammonium persulfate and sodium bisulfite is 100-110: 3-6: 11-20g: 0.4-0.75: 115-130: 1.5-2.2: 1.5-2.

2.

28. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The ammonium persulfate and sodium bisulfite are both added in the form of an aqueous solution with a mass fraction of 3-4.5%.

29. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The heating temperature is 55-65° C., and the graft copolymerization reaction time is 2-3 hours.

30. The high-strength and high-wear-resistant marine ultra-high performance concrete material according to claim 24, characterized in that: The particles are washed with at least one of methanol and ethanol and then vacuum dried at 50-70° C. for 10-12 hours to obtain the modified rubber particles.

31. Application of the high-strength and high-wear-resistant marine ultra-high performance concrete material according to any one of claims 19 to 30 in construction engineering, marine engineering, bridge engineering, road engineering, and water conservancy and hydropower engineering.

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