Fiber-reinforced modified coarse aggregate and maritime work ultra-high performance concrete material and application thereof

Abstract

The invention relates to the technical field of maritime work concrete preparation, and particularly discloses a fiber-reinforced modified coarse aggregate and a maritime work ultra-high performance concrete material and application thereof. The concrete material is prepared from the following components in parts by weight: 495 to 688 parts of a cement binding material, 200 to 800 parts of the fiber-reinforced modified coarse aggregate, 22 to 138 parts of modified rubber particles, 142 to 197 parts of fly ash, 71 to 98 parts of silica fume, 708 to 983 parts of quartz sand, 78 to 157 parts of reinforced fibers, 14 to 20 parts of a water reducing agent and 113 to 160 parts of water. The fiber-reinforced modified coarse aggregate and the modified rubber particles are added into the ultra-high performance concrete material, so that the concrete material prepared by the invention has high strength, high abrasion resistance and crack resistance, thereby better adapting to service in a marine environment.

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 the 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 a person skilled in the art.

[0003] With nearly 40 years of large-scale port construction, my country has accumulated rich experience and advanced port construction technology. Concrete is the main building material for coastal port buildings, but port concrete buildings are not only affected by marine environmental factors such as ambient temperature and humidity changes, chloride ion corrosion, but also by unstable wind loads, wave loads, ship berthing loads, stacked cargo loads and vehicle loads. Traditional concrete is difficult to cope with the special service needs in complex marine environments due to its lack of strength, crack resistance and durability.

[0004] At present, ultra-high performance concrete (UHPC) is being continuously promoted and applied in special engineering fields. UHPC uses quartz sand with fine particle size and stable material as aggregate, and uses cement, fly ash, silica fume and other mineral admixtures as cementitious materials, and the volume proportion of cementitious materials in the entire UHPC system is extremely high. In addition, the extremely low water-cement ratio of UHPC and the efficient filling effect of mineral admixtures make its internal structure density significantly higher than that of traditional concrete. Therefore, the overall performance of UHPC is excellent, and the strength can reach 3 to 16 times that of traditional concrete. At the same time, due to the addition of external fiber materials, the defects of concrete such as poor toughness, poor crack resistance and low tensile strength are improved. The ductility and energy absorption capacity of UHPC are usually 300 times that of traditional concrete. However, UHPC has insufficient anti-abrasion performance under dynamic load environment, especially in the seawater scouring scene in the ocean, which is prone to surface peeling. Therefore, improving the wear resistance of UHPC is crucial to further improve its promotion and 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, which, by adding fiber-reinforced modified coarse aggregate and modified rubber particles, enables the concrete material prepared by the present invention to have high strength, high impact and abrasion resistance and crack resistance, so as to better adapt to service in the marine environment. 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: (1) The rock coarse aggregate is placed in a rotating drum sandblasting chamber, and then the rolling rock coarse aggregate is processed by using steel sand sprayed from its nozzle. After separating and removing the steel sand, the modified coarse aggregate is obtained and set aside.

[0007] (2) A matrix type melting lattice is formed on the surface of the modified coarse aggregate by using a laser beam in an inert gas, and then steel fibers are inserted into the melting points of the melting lattice. After cooling, the fiber-reinforced coarse aggregate is obtained.

[0008] (3) Soaking the fiber-reinforced coarse aggregate in a silicate solution, separating the fiber-reinforced coarse aggregate after immersion, drying the coarse aggregate, and then placing the coarse aggregate in ethanol containing a silane coupling agent for standing, separating the coarse aggregate after immersion, and obtaining the fiber-reinforced modified coarse aggregate after drying.

[0009] Furthermore, in step (1), the particle size of the rock coarse aggregate is 5-10 mm.

[0010] Furthermore, in step (1), the fineness of the steel sand 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°.

[0011] Furthermore, in step (1), the rotation speed of the rotary drum sandblasting chamber is 4-10 r / min.

[0012] Furthermore, in step (1), the surface treatment is performed until the surface roughness of the coarse aggregate reaches Ra=15~25μm.

[0013] Furthermore, in step (2), the distance between adjacent melting points in the melting point lattice is 2-4 mm. Optionally, the inert gas includes any one of helium, argon, nitrogen, etc.

[0014] Furthermore, in step (2), the melting depth of the melting point matrix 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.

[0015] Furthermore, in step (2), the length of the steel fiber is 8-14 mm, and the diameter is 0.18-0.22 mm.

[0016] Furthermore, in step (3), the ratio of the fiber-reinforced coarse aggregate to the silicate solution is 1 g: 10-20 ml. Optionally, the mass fraction of the silicate solution is 5-11%. The silicate includes at least one of sodium silicate, potassium silicate, etc.

[0017] Furthermore, in step (3), the soaking and standing time are both 20 to 30 minutes.

[0018] 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.

[0019] Secondly, the present invention provides a high-strength and high-wear-resistant marine engineering ultra-high performance concrete material, comprising the following components: 495-688 parts by weight of cementitious material, 200-800 parts by weight of the fiber-reinforced modified coarse aggregate of the present invention, 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 water reducer, and 113-160 parts by weight of water.

[0020] Further, the reinforcing fiber includes at least one of steel fiber, plastic fiber, carbon fiber, etc. Optionally, the reinforcing fiber has a length of 8-20 mm and a diameter of 0.18-0.22 mm.

[0021] Furthermore, the fineness of the quartz sand and rubber particles is 20-40 mesh.

[0022] 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.

[0023] Furthermore, the rubber particles are modified rubber particles treated by the following method: the rubber particles are surface treated by plasma formed by a mixed gas of ammonia and oxygen. The obtained modified rubber particles are then mixed with a modified solution formed by butyl acrylate, hydroxyethyl methacrylate, nano-silicon dioxide, and water, and then ammonium persulfate and sodium bisulfite are added to carry out a graft copolymerization reaction under heating conditions. After completion, the particles are separated, washed, and dried to obtain the modified rubber particles.

[0024] 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, and at the same time etches the surface of the rubber particles to increase the roughness.

[0025] Furthermore, the mass ratio of the modified rubber 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. Optionally, the ammonium persulfate and sodium bisulfite are added in the form of an aqueous solution with a mass fraction of 3-4.5%.

[0026] Furthermore, the heating temperature is 55-65° C., and the graft copolymerization reaction time is 2-3 hours.

[0027] Furthermore, the particles are washed with at least one of methanol, ethanol, etc. and then vacuum dried at 50-70° C. for 10-12 hours to obtain the modified rubber particles. In this process, the monomers containing amino groups and hydroxyl groups (i.e., butyl acrylate and hydroxyethyl methacrylate) are grafted onto the surface of the rubber particles with the active sites as anchor points, thereby improving the bonding force between the rubber particles and the concrete matrix. At the same time, the nano-silicon dioxide is attached to the surface of the rubber particles to improve the hardness and strength of the rubber particles.

[0028] 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.

[0029] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: (1) The ultra-high performance concrete material of the present invention adds 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 formed pits 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 lattice on the surface of the modified coarse aggregate obtained by the above treatment, and then inserts steel fibers into the melting points. In this way, after cooling, the melting points re-solidify and harden, and one end of the steel fiber can be firmly fixed to the coarse aggregate to form a structure with steel fibers anchored on the surface. After being added to 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, when subjected to external scouring, the mechanical interlocking effect can effectively prevent the surface of the concrete structure from peeling off, thereby improving the anti-abrasion performance, so that the concrete material of the present invention has better durability when serving in the marine environment. In addition, the linkage effect can also significantly inhibit cracks caused by volume shrinkage during the hardening process of the concrete material, preventing the problem of a decrease in the mechanical strength of the concrete material caused by this.

[0030] (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 force 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 bonds and the aluminum-oxygen covalent bonds, 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 monomer is convenient for subsequent reaction with the hydration product calcium hydroxide to form hydrated calcium silicate and hydrated calcium aluminate, thereby enhancing the hardening strength of cement and further improving the anchoring effect on steel fibers, thereby improving the mechanical strength of concrete materials. The silane coupling agent can penetrate into the coarse aggregate, improve the bonding force between the aggregate and the concrete matrix, and increase the strength of the concrete.

[0031] (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 surface of the rubber particles, 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 interface 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 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 site as an anchor point to graft the amino-containing monomer butyl acrylate and the hydroxyl-containing monomer hydroxyethyl methacrylate onto the surface of the rubber particles, and forms 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-silicon dioxide is attached to the surface of the rubber particles to improve the hardness and strength of the rubber particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, 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.

[0033] Figure 1 The following is a compressive strength test diagram of Example 1.

[0034] Figure 2 The following is a graph showing the splitting tensile strength test of Example 1.

[0035] Figure 3 This is a test diagram of the anti-abrasion strength of the following Example 1.

[0036] Figure 4 This is a test graph of chloride ion diffusion coefficient of the following Example 1.

[0037] Figure 5 This is a test diagram of the anti-abrasion strength of the following Example 2.

[0038] Figure 6 This is a test diagram of the anti-abrasion strength of the following Example 3.

[0039] Figure 7 This is a test diagram of the anti-abrasion strength of the following Example 4.

[0040] Figure 8 This is a test diagram of the anti-abrasion strength of the following Example 5.

[0041] Fig. 9 This is a test diagram of the anti-abrasion strength of the following Example 6.

[0042] Fig.10 This is a graph showing the abrasion resistance test of the following Example 7.

[0043] Fig.11 This is a test diagram of the anti-abrasion strength of the following Example 8. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0045] 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 or raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in a conventional manner in the art or in accordance with the product instructions.

[0046] In addition, any method and material similar or equivalent to the described content can be applied to the method of the present invention. The technical solution of the present invention is further described in conjunction with the accompanying drawings and specific embodiments.

[0047] Example 1 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps: (1) Wash the granite crushed stone coarse aggregate with a particle size distribution between 5 and 7 mm with water, air dry it, and then place it in a rotating drum sandblasting chamber with a rotation speed of 5 r / min. Then use an air compression system to drive 100-mesh steel sand to spray 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 is set to 20 cm, the inclination angle relative to the coarse aggregate is set to 60°, the nozzle diameter is 10 mm, and the steel sand speed is 220 m / s. At the same time, a laser profiler is used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reaches 15 μm, the treatment is stopped. Then, the residual steel sand in the coarse aggregate is removed by a high-pressure cyclone with an air pressure of 0.3 MPa, and the modified coarse aggregate is obtained for standby use.

[0048] (2) The laser beam emitted by the fiber laser (wavelength set to 1064nm, power set to 1.8kW / cm 2 , the spot diameter is 1.5mm, the scanning speed is 1m / min) using a three-dimensional dynamic focusing system to form a matrix melting point array with a melting depth of 3±0.2mm on the surface of the modified coarse aggregate, wherein the spacing between adjacent melting points is set to 3mm. Then, the modified coarse aggregate is fixed by a six-axis robotic arm equipped with an electromagnetic positioning fixture, and a steel fiber with a length of 10mm and a diameter of 0.2mm is inserted into the melting point, and cooled to room temperature to obtain a fiber-reinforced coarse aggregate for use.

[0049] (3) The fiber-reinforced coarse aggregate is 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 is filtered out and dried at 80°C. Then, it is mixed with ethanol containing 5wt.% 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 is filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for use.

[0050] 2. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps: (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 560 parts by weight, 600 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 120 parts by weight of 40-mesh rubber particles, 160 parts by weight of Class I fly ash, and silica fume (specific surface area of ​​16880 m 2 / kg), 80 parts by weight of quartz sand of 40 mesh, 870 parts by weight of end hook type copper-plated steel fiber (length 14 mm, diameter 0.22 mm), 130 parts by weight of polycarboxylic acid water-reducing agent (water-reducing rate 30.6%), and 140 parts by weight of water.

[0051] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume and quartz sand are mixed and stirred for 2 minutes, and then the water and water reducing agent are added and stirred for 5 minutes to obtain a slurry. Then, the steel fiber is poured into a mesh screen with a pore size of 0.5 mm, and the mesh screen is shaken to evenly disperse the steel fiber into the stirring slurry, and the ultra-high performance concrete material is obtained by stirring for 8 minutes.

[0052] 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 test specimens prepared from the ultra-high performance concrete material of this embodiment (standard curing, age 28 days) were tested (respectively as Figure 1 , Figure 2 , Figure 3 , Figure 4 The results are shown in the following table: .

[0053] Example 2 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps: (1) Wash the granite crushed stone coarse aggregate with a particle size distribution between 8 and 10 mm with water, air dry it, and then place it in a rotating drum sandblasting chamber with a rotation speed of 10 r / min. Then use an air compression system to drive 80-mesh steel sand to spray 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 is set to 30 cm, the inclination angle relative to the coarse aggregate is set to 45°, the nozzle diameter is 10 mm, and the steel sand speed is 240 m / s. At the same time, a laser profiler is used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reaches 20 μm, the treatment is stopped. Then, the residual steel sand in the coarse aggregate is removed by a high-pressure cyclone with an air pressure of 0.3 MPa, and the modified coarse aggregate is obtained for standby use.

[0054] (2) The laser beam emitted by the fiber laser (wavelength set to 1200nm, power set to 1.5kW / cm 2 , the diameter of the spot is 1.2mm, and the scanning speed is 1.3m / min) A three-dimensional dynamic focusing system is used to form a matrix melting point array with a melting depth of 3±0.2mm on the surface of the modified coarse aggregate, wherein the spacing between adjacent melting points is set to 2mm. Then, the modified coarse aggregate is fixed by a six-axis robotic arm equipped with an electromagnetic positioning fixture, and a steel fiber with a length of 8mm and a diameter of 0.18mm is inserted into the melting point, and cooled to room temperature to obtain a fiber-reinforced coarse aggregate for use.

[0055] (3) The fiber-reinforced coarse aggregate is 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 is filtered out and dried at 80°C. Then, it is 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 is filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for use.

[0056] 2. A method for preparing modified rubber particles, comprising the following steps: (I) A radio frequency glow discharge plasma reactor (power set at 200 W) was used to generate a low-temperature plasma from a mixture of ammonia and oxygen (volume ratio 2.5:1), and then the plasma was used to spray argon gas at 100 Pa on rubber particles with a fineness of 20 mesh for surface treatment for 30 min.

[0057] (II) The obtained modified rubber particles were mixed with the modified solution formed by butyl acrylate, hydroxyethyl methacrylate, nano-silica and water, and stirred for 15 minutes, and then ammonium persulfate and sodium bisulfite were added and heated 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 was 100:3:11g:0.4:130:1.5:1.5, and the ammonium persulfate and sodium bisulfite were dripped in the form of 3% aqueous solution in 1 hour. After completion, the particles were filtered out, washed with ethanol 3 times, and then vacuum dried at 70°C for 10 hours to obtain modified rubber particles for standby use.

[0058] 3. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps: (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 688 parts by weight, 800 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 138 parts by weight of the modified rubber particles of this embodiment, 197 parts by weight of Class I fly ash, and silica fume (with a specific surface area of ​​16880m 2 / kg), 98 parts by weight of quartz sand of 20 mesh, 983 parts by weight of end hook type copper-plated steel fiber (length 8 mm, diameter 0.22 mm), 157 parts by weight of polycarboxylic acid water-reducing agent (water-reducing rate 30.6%), and 160 parts by weight of water.

[0059] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume and quartz sand are mixed and stirred for 2 minutes, and then the water and water reducing agent are added and stirred for 5 minutes to obtain a slurry. Then, the steel fiber is poured into a mesh screen with a pore size of 0.5 mm, and the mesh screen is shaken to evenly disperse the steel fiber into the stirring slurry, and the ultra-high performance concrete material is obtained by stirring for 8 minutes.

[0060] 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: .

[0061] Example 3 1. A fiber-reinforced modified coarse aggregate, which is obtained by the following steps: (1) Wash the granite crushed stone coarse aggregate with a particle size distribution between 6 and 8 mm with water, air dry it, and then place it in a rotating drum sandblasting chamber with a rotation speed of 4r / min. Then use an air compression system to drive 120-mesh steel sand to spray 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 is set to 15cm, the inclination angle relative to the coarse aggregate is set to 75°, the nozzle diameter is 10mm, and the steel sand speed is 250m / second. At the same time, a laser profiler is used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reaches 25μm, the treatment is stopped. Then, the residual steel sand in the coarse aggregate is removed by a high-pressure cyclone with an air pressure of 0.3MPa, and the modified coarse aggregate is obtained for standby use.

[0062] (2) The laser beam emitted by the fiber laser (wavelength set to 1000nm, power set to 2.5kW / cm 2 , the diameter of the spot is 1.8mm, and the scanning speed is 1.5m / min) A three-dimensional dynamic focusing system is used to form a matrix melting point array with a melting depth of 3±0.2mm on the surface of the modified coarse aggregate, wherein the spacing between adjacent melting points is set to 4mm. Then, the modified coarse aggregate is fixed by a six-axis robotic arm equipped with an electromagnetic positioning fixture, and a steel fiber with a length of 14mm and a diameter of 0.22mm is inserted into the melting point, and cooled to room temperature to obtain a fiber-reinforced coarse aggregate for use.

[0063] (3) The fiber-reinforced coarse aggregate is 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 is filtered out and dried at 80°C. Then, it is 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 is filtered out and dried at 60°C to obtain the fiber-reinforced modified coarse aggregate for use.

[0064] 2. A method for preparing modified rubber particles, comprising the following steps: (I) A radio frequency glow discharge plasma reactor (power setting is 100 W) is used to generate a low-temperature plasma from a mixture of ammonia and oxygen (volume ratio 4:1), and then the plasma is used to spray 80 Pa of argon gas on rubber particles with a fineness of 30 mesh to perform surface treatment for 5 minutes.

[0065] (II) The obtained modified rubber particles were mixed with the modified solution formed by butyl acrylate, hydroxyethyl methacrylate, nano-silica and water, and stirred for 15 minutes, and then ammonium persulfate and sodium bisulfite were added and heated to 65°C in a water bath for 2 hours. The mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silica, water, ammonium persulfate and sodium bisulfite was 110:6:20g:0.75:115:2.2:2.2, and the ammonium persulfate and sodium bisulfite were dripped in the form of an aqueous solution with a mass fraction of 4.5% in 1 hour. After completion, the particles were filtered out, washed with ethanol 3 times, and vacuum dried at 50°C for 12 hours to obtain modified rubber particles for standby use.

[0066] 3. A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, comprising the following steps: (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / kg), 495 parts by weight, 200 parts by weight of the fiber-reinforced modified coarse aggregate of this embodiment, 22 parts by weight of the modified rubber particles of this embodiment, 142 parts by weight of Class I fly ash, and silica fume (with a specific surface area of ​​16880m 2 / kg), 71 parts by weight of quartz sand of 40 mesh, 708 parts by weight of end hook type copper-plated steel fiber (length 20 mm, diameter 0.18 mm), 14 parts by weight of polycarboxylic acid water-reducing agent (water-reducing rate 30.6%), and 113 parts by weight of water.

[0067] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume and quartz sand are mixed and stirred for 2 minutes, and then the water and water reducing agent are added and stirred for 5 minutes to obtain a slurry. Then, the steel fiber is poured into a mesh screen with a pore size of 0.5 mm, and the mesh screen is shaken to evenly disperse the steel fiber into the stirring slurry, and the ultra-high performance concrete material is obtained by stirring for 8 minutes.

[0068] 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: .

[0069] Example 4 A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, which differs from the above-mentioned embodiment 1 in that: the present embodiment adopts the following steps to prepare a reinforced modified coarse aggregate instead of the fiber-reinforced modified coarse aggregate of embodiment 1: (1) Wash the granite crushed stone coarse aggregate with a particle size distribution between 5 and 7 mm with water, air dry it, and then place it in a rotating drum sandblasting chamber with a rotation speed of 5 r / min. Then use an air compression system to drive 100-mesh steel sand to spray 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 is set to 20 cm, the inclination angle relative to the coarse aggregate is set to 60°, the nozzle diameter is 10 mm, and the steel sand speed is 220 m / s. At the same time, a laser profiler is used to monitor the surface roughness Ra of the coarse aggregate surface in real time. When the Ra value reaches 15 μm, the treatment is stopped. Then, the residual steel sand in the coarse aggregate is removed by a high-pressure cyclone with an air pressure of 0.3 MPa, and the modified coarse aggregate is obtained for standby use.

[0070] (2) The modified coarse aggregate is 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 is filtered out and dried at 80°C. Then, it is mixed with ethanol containing 5wt.% 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 is filtered out and dried at 60°C to obtain the reinforced modified coarse aggregate.

[0071] 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: .

[0072] Example 5 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: (1) The coarse aggregate of granite crushed stone 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 directed to the surface of the granite crushed stone in a helium protective gas. 2 , the diameter of the spot is 1.2mm, and the scanning speed is 1.3m / min) A matrix melting point array with a melting depth of 3±0.2mm is formed on the surface of the granite crushed stone coarse aggregate using a three-dimensional dynamic focusing system, wherein the spacing between adjacent melting points is set to 2mm. Then, the modified coarse aggregate is fixed by a six-axis robotic arm equipped with an electromagnetic positioning fixture, and a steel fiber with a length of 8mm and a diameter of 0.18mm is inserted into the melting point, and cooled to room temperature to obtain a fiber-reinforced coarse aggregate for use.

[0073] (2) The fiber-reinforced coarse aggregate is 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 is filtered out and dried at 80° C., and then 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 is filtered out and dried at 60° C. to obtain the fiber-reinforced modified coarse aggregate.

[0074] 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: .

[0075] Example 6 A method for preparing a high-strength and high-wear-resistant marine engineering ultra-high performance concrete material comprises the following steps: (S1) Weigh the following components: cement (PII 42.5R, specific surface area 382m 2 / 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 of 40 mesh, 870 parts by weight of end hook type copper-plated steel fiber (length 14 mm, diameter 0.22 mm), 130 parts by weight of polycarboxylic acid water-reducing agent (water-reducing rate 30.6%), and 140 parts by weight of water.

[0076] (S2) The cement, fiber-reinforced modified coarse aggregate, rubber particles, fly ash, silica fume and quartz sand are mixed and stirred for 2 minutes, and then the water and water reducing agent are added and stirred for 5 minutes to obtain a slurry. Then, the steel fiber is poured into a mesh screen with a pore size of 0.5 mm, and the mesh screen is shaken to evenly disperse the steel fiber into the stirring slurry, and the ultra-high performance concrete material is obtained by stirring for 8 minutes.

[0077] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Fig. 9 The chloride ion diffusion coefficient was tested and the results are shown in the following table: .

[0078] Example 7 A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, which differs from the above-mentioned embodiment 3 in that: the modified rubber particles in this embodiment are obtained by the following steps: a mixed gas of ammonia and oxygen (volume ratio 4:1) is formed into a low-temperature plasma using a radio frequency glow discharge plasma reactor (power set to 100W), and then the plasma is used to spray 80Pa of argon gas on rubber particles with a fineness of 30 mesh for surface treatment for 5 minutes to obtain modified rubber particles.

[0079] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Fig.10 The chloride ion diffusion coefficient was tested and the results are shown in the following table: .

[0080] Example 8 A method for preparing a high-strength and high-wear-resistant marine ultra-high performance concrete material, which differs from the above-mentioned embodiment 2 in that the modified rubber particles of this embodiment are obtained by the following steps: mixing the rubber particles with a fineness of 20 mesh with a modified solution formed by butyl acrylate, hydroxyethyl methacrylate, nano-silicon dioxide, and water, and stirring for 15 minutes, then adding ammonium persulfate and sodium bisulfite and heating them in a water bath to 55°C for 3 hours, wherein the mass ratio of the modified rubber particles, butyl acrylate, hydroxyethyl methacrylate, nano-silicon dioxide, 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 dripped in the form of an aqueous solution with a mass fraction of 3% in 1 hour. After completion, the particles are filtered out, washed with ethanol 3 times, and then vacuum dried at 70°C for 10 hours to obtain modified rubber particles.

[0081] Performance test: The same method as in Example 1 was used to test the compressive strength, splitting tensile strength, and abrasion resistance (such as Fig.11 The chloride ion diffusion coefficient was tested and the results are shown in the following table: .

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope 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-type sandblasting chamber, and then using steel sand sprayed 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 by 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) Soaking the fiber-reinforced coarse aggregate in a silicate solution, separating the fiber-reinforced coarse aggregate after immersion, drying the coarse aggregate, and then placing the coarse aggregate in ethanol containing a silane coupling agent for standing, separating the coarse aggregate after immersion, and obtaining the fiber-reinforced modified coarse aggregate after drying.

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; Optionally, 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°; Optionally, in step (1), the particle size of the rock coarse aggregate is 5-10 mm; Optionally, in step (1), the surface treatment is performed until the surface roughness of the coarse aggregate reaches Ra=15~25μm; Optionally, in step (1), the rotation speed of the rotary drum sandblasting chamber is 4-10 r / min.

3. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the spacing between adjacent melting points in the melting point lattice is 2-4 mm; optionally, the inert gas includes any one of helium, argon and nitrogen.

4. The fiber-reinforced modified coarse aggregate according to claim 1, characterized in that: In step (2), the melting depth of the melting point matrix is ​​3±0.2 mm; Optionally, 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; Optionally, in step (2), the steel fiber has a length of 8-14 mm and a diameter of 0.18-0.22 mm.

5. 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; Optionally, the mass fraction of the silicate solution is 5-11%; Optionally, the silicate includes at least one of sodium silicate and potassium silicate; Optionally, in step (3), the soaking and standing time are both 20 to 30 minutes.

6. The fiber-reinforced modified coarse aggregate according to any one of claims 1 to 5, 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; Optionally, in step (3), the mass fraction of the silane coupling agent in the ethanol is 4-8%; Optionally, in step (3), the silane coupling agent includes at least one of KH550, KH560, and KH570.

7. A high-strength and high-wear-resistant marine engineering ultra-high performance concrete material, characterized in that: The invention comprises the following components: 495-688 parts by weight of cementitious material, 200-800 parts by weight of fiber-reinforced modified coarse aggregate according to any one of claims 1 to 6, 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 water reducing agent, and 113-160 parts by weight of water; Optionally, the reinforcing fiber includes at least one of steel fiber, plastic fiber, and carbon fiber; Optionally, the reinforcing fiber has a length of 8 to 20 mm and a diameter of 0.18 to 0.22 mm; Optionally, the fineness of the quartz sand and rubber particles is 20-40 mesh; Optionally, the water reducer includes at least one of a polycarboxylate water reducer, a naphthalene-based water reducer, and a lignin sulfonate water reducer.

8. The high-strength and high-wear-resistant marine engineering ultra-high performance concrete material according to claim 7, characterized in that: The rubber particles are modified rubber particles treated by the following method: the rubber particles are surface treated by plasma formed by a mixed gas of ammonia and oxygen; the modified rubber particles are then mixed with a modified solution formed by butyl acrylate, hydroxyethyl methacrylate, and nano-silicon dioxide, and then ammonium persulfate and sodium bisulfite are added to carry out a graft copolymerization reaction under heating conditions; after completion, the particles are separated, washed, and dried to obtain the modified rubber particles.

9. The high-strength and high-wear-resistant marine engineering ultra-high performance concrete material according to claim 8, characterized in that: The volume ratio of ammonia to oxygen is 2.5-4:1; Optionally, the surface treatment time is 5 to 30 minutes; Optionally, the mass ratio of the modified rubber 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; Optionally, the ammonium persulfate and sodium bisulfite are added in the form of aqueous solutions with a mass fraction of 3 to 4.5%; Optionally, the heating temperature is 55-65° C., and the graft copolymerization reaction time is 2-3 hours; Optionally, 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.

10. Application of the high-strength and high-wear-resistant marine engineering ultra-high performance concrete material according to any one of claims 7 to 9 in construction engineering, marine engineering, bridge engineering, road engineering, water conservancy and hydropower engineering.

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