Energy-saving uHPC concrete and preparation method thereof

Abstract

The application discloses energy-saving UHPC concrete and a preparation method thereof, and relates to the field of concrete.The concrete comprises the following raw materials in parts by weight: 110-150 parts of Portland cement, 18-35 parts of fly ash, 20-30 parts of KH550 modified glass beads, 50-75 parts of ethenyl ester resin matrix modified composite fiber rib, 20-38 parts of silica ash, 100-175 parts of fine sand, 30-70 parts of steel fiber, 4-9 parts of water reducing agent and 25-45 parts of water.The UHPC concrete has the advantages of small self-shrinkage, low early cracking risk and good corrosion resistance.

Description

Technical Field

[0001] This application relates to the field of concrete technology, and in particular to an energy-saving UHPC concrete and its preparation method. Background Technology

[0002] Ultra-high performance concrete (UHPC), as a cement-based composite material, possesses high strength, high toughness, and low porosity. Its mechanical and durability properties far surpass those of ordinary concrete (NSC) and high-performance concrete (HPC), and its compressive and flexural strengths are also excellent. Therefore, it is widely used in various fields such as building construction, bridge engineering, tunnels, and underground engineering. However, UHPC is not without its drawbacks. Due to its low water-cement ratio, high cementitious material content, high content of active mineral admixtures, and low coarse aggregate content, it exhibits significant autogenous shrinkage during setting, hardening, and service life. Autogenous shrinkage accounts for over 80% of the total shrinkage, greatly increasing the risk of early cracking and becoming one of the key technical challenges limiting the further promotion of UHPC in engineering applications. Furthermore, shrinkage cracking allows corrosive ions to penetrate the concrete, significantly reducing its mechanical strength and durability, accelerating corrosion and aging, and leading to premature deterioration and failure of the structure, seriously affecting the practicality and safety of marine infrastructure. Summary of the Invention

[0003] In order to solve at least one of the above-mentioned technical problems and develop an ultra-high performance concrete with low autogenous shrinkage, low risk of early cracking and good corrosion resistance, this application provides an energy-saving UHPC concrete and its preparation method.

[0004] In a first aspect, this application provides an energy-saving UHPC concrete, wherein the concrete comprises the following raw materials by weight: 110-150 parts of silicate cement, 18-35 parts of fly ash, 20-30 parts of KH550 modified glass microspheres, 50-75 parts of vinyl ester resin matrix modified composite fiber reinforcement, 20-38 parts of silica fume, 100-175 parts of fine sand, 30-70 parts of steel fiber, 4-9 parts of water-reducing agent, and 25-45 parts of water;

[0005] The vinyl ester resin matrix modified composite fiber reinforcement is prepared by modifying the composite fiber with a vinyl ester resin matrix;

[0006] The preparation method of the vinyl ester resin matrix modified composite fiber reinforcement includes the following steps:

[0007] A1. Mix hydrogen-containing silicone oil and KH560 at a mass ratio of 1:1, add solvent and catalyst and stir to carry out addition reaction to obtain organosilicon for later use.

[0008] A2, the halloysite nanotube is mixed with ethanol, then hydrogen-containing silicone oil and ethyl silicate are added and mixed to obtain modified halloysite nanotubes;

[0009] A3, hydrogen-containing silicone oil and ethyl silicate are mixed, and then added dropwise to the surface of expanded vermiculite, and then expanded in a microwave oven, and then stirred in a mixed solution of KOH and anhydrous ethanol, and then mixed to obtain modified expanded vermiculite;

[0010] A4, a vinyl ester resin emulsion is prepared by mixing vinyl ester resin, peroxide cyclohexanone dibutyl paste and cobalt naphthenate styrene liquid in a weight ratio of 100: (1-3): (0.5-1.5);

[0011] A5, the vinyl ester resin emulsion of step A4, the organic silicon of step A1, the modified halloysite nanotubes of step A2 and the modified expanded vermiculite of step A3 are mixed in a weight ratio of 100: (5-10): (0.5-1): (0.5-1) to obtain a vinyl ester resin matrix;

[0012] A6, the composite fiber is immersed in the vinyl ester resin matrix of step A5, and then subjected to pultrusion, rib forming, curing and cutting to obtain the vinyl ester resin matrix modified composite fiber rib;

[0013] The composite fiber of step A6 is prepared by mixing polypropylene fiber and polyvinyl alcohol fiber in a weight ratio of 1:1.

[0014] By adopting the technical scheme, the energy-saving UHPC concrete provided by the application effectively improves the performance of the concrete by using specific proportions of raw materials and a unique preparation method of the ethenyl ester resin matrix modified composite fiber bar. In terms of raw materials, Portland cement, as the main cementitious material, cooperates with fly ash to provide basic strength for the concrete. KH550 modified glass beads can improve the internal structure of the concrete and reduce the risk of shrinkage. Silica fume further fills the pores and enhances the compactness of the concrete. Fine sand, as fine aggregate, together with other ingredients, forms a stable structure. Steel fibers can bridge cracks and transfer stress. The polypropylene fiber and polyvinyl alcohol fiber in the ethenyl ester resin matrix modified composite fiber bar bear the tensile force and delay the development of cracks. The ethenyl ester resin matrix modification makes the fiber and the concrete matrix have better adhesion, thereby enhancing the crack resistance. In terms of solving the corrosion of concrete and improving the durability, when preparing the ethenyl ester resin matrix modified composite fiber bar, the organic silicon generated by the reaction of hydrogen-containing silicone oil and KH560 in step A1 provides chemical stability and hydrophobicity. The modified halloysite nanotubes in step A2 and the modified expanded vermiculite in step A3 can form a physical barrier and fill the pores to reduce the channel of corrosive media. The emulsion prepared by mixing the ethenyl ester resin, peroxide cyclohexanone dibutyl paste, and cobalt naphthenate styrene liquid in step A4, and the three-dimensional network structure formed by the solidification of the ethenyl ester resin, ensures the solidification by the action of the initiator and the accelerator, and isolates the corrosion of the corrosive medium. At the same time, the water-reducing agent reduces the water-binder ratio and reduces the transmission channel of the corrosive medium, thereby improving the corrosion resistance of the fiber reinforced bar and the durability of the concrete. These measures not only significantly improve the compressive strength, flexural strength, and fracture toughness of UHPC, but also effectively reduce the risk of autogenous shrinkage and early cracking, prolong the service life of the concrete, and make it have a wide application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering, etc.

[0015] Optionally, the weight ratio of the halloysite nanotube, ethanol, hydrogen-containing silicone oil, and ethyl silicate in step A2 is 1: (50-100): 1: (2-4).

[0016] By adopting the technical scheme, the uniform dispersion of halloysite nanotubes in ethanol and the effective mixing of hydrogen-containing silicone oil and ethyl silicate are ensured, and stable modified halloysite nanotubes are formed. This modification process significantly improves the dispersibility and interfacial bonding strength of halloysite nanotubes in the ethenyl ester resin matrix, thereby enhancing the mechanical properties and durability of the composite material. The addition of modified halloysite nanotubes not only improves the microstructure of the concrete and reduces the generation of micro-defects, but also improves the compactness and crack resistance of the concrete, effectively solving the problems of large autogenous shrinkage and high early cracking risk of UHPC during setting, hardening and service. At the same time, the physical barrier effect of the modified halloysite nanotubes also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete.

[0017] Optionally, the weight ratio of the hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and anhydrous ethanol in the mixed solution in step A3 is (1-3):(3-9):(0.5-1):(50-100).

[0018] By adopting the above technical scheme, the expanded vermiculite is effectively mixed with the hydrogen-containing silicone oil and the ethyl silicate in the surface modification process, and the modified expanded vermiculite is formed. This modification process significantly improves the dispersibility and stability of the expanded vermiculite in the vinyl ester resin matrix, thereby not only optimizing the microstructure of the concrete and reducing the generation of micro-defects, but also improving the compactness and crack resistance of the concrete, effectively solving the problems of large self-shrinkage and high risk of early cracking of UHPC in the setting and hardening and service processes. At the same time, the physical barrier effect of the modified expanded vermiculite also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete, and prolonging the service life of the concrete.

[0019] Optionally, the weight ratio of the composite fiber and the vinyl ester resin matrix in step A6 is (3.5-5):1.

[0020] By adopting the above technical scheme, the uniform distribution and sufficient infiltration of the composite fiber in the vinyl ester resin matrix are ensured, and the excellent performance of the vinyl ester resin matrix modified composite fiber reinforced bar is formed. This optimized ratio not only improves the tensile strength and corrosion resistance of the composite fiber reinforced bar, but also significantly enhances the interfacial bonding strength between the composite fiber reinforced bar and the concrete matrix, thereby effectively delaying the development and penetration of cracks, and improving the compressive strength and fatigue resistance of the concrete. The addition of the composite fiber reinforced bar further optimizes the microstructure of the concrete, reduces the generation of micro-defects, improves the compactness and crack resistance of the concrete, and effectively solves the problems of large self-shrinkage and high risk of early cracking of UHPC in the setting and hardening and service processes. At the same time, the physical barrier effect of the composite fiber reinforced bar also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete, and prolonging the service life of the concrete.

[0021] Optionally, the weight ratio of the KH550 modified glass microbeads and the vinyl ester resin matrix modified composite fiber reinforced bar is 1:(2.2-2.8).

[0022] By adopting the above technical scheme, when the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:(2.2-2.8), the uniform distribution and effective combination of the KH550 modified glass beads in the vinyl ester resin matrix modified composite fiber bar are ensured. This optimized ratio not only improves the dispersibility and stability of the glass beads in the matrix, but also significantly enhances the microstructure of the concrete, reduces the generation of micro-defects, and improves the compactness and crack resistance of the concrete. The addition of the KH550 modified glass beads further optimizes the mechanical properties of the concrete, improves its compressive strength and flexural strength, and the surface modification treatment provides chemical stability and hydrophobicity, effectively reducing the penetration of water and other corrosive media, improving the corrosion resistance and durability of the concrete. This technical scheme effectively solves the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service, prolongs the service life of the concrete, and has a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0023] Optionally, the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.5.

[0024] Optionally, the diameter of the vinyl ester resin matrix modified composite fiber bar is 5-10mm.

[0025] By adopting the above technical scheme, this optimized diameter range not only improves the tensile strength and corrosion resistance of the composite fiber bar, but also significantly enhances the interfacial bonding strength between the composite fiber bar and the concrete matrix, thereby effectively delaying the development and penetration of cracks and improving the stability of the concrete. The moderate diameter of the composite fiber bar can form an effective three-dimensional network structure in the concrete, further optimizing the microstructure of the concrete, reducing the generation of micro-defects, improving the compactness and crack resistance of the concrete, and effectively solving the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service. At the same time, the physical barrier effect of the composite fiber bar also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete and prolonging the service life of the concrete.

[0026] Optionally, the Portland cement is a PO42.5 grade ordinary Portland cement.

[0027] Optionally, the solvent in step A1 is selected from ethanol; and the catalyst is selected from NaOH.

[0028] In a second aspect, the application provides a preparation method of energy-saving UHPC concrete, comprising the following steps: S1, weighing each raw material according to the proportion;

[0029] S2, mixing and stirring silicate cement, fly ash, KH550 modified glass beads, silica fume, fine sand and 75% water to obtain a first mixture;

[0030] S3, adding the remaining water and water reducing agent into the first mixture of step S2 to obtain a second mixture;

[0031] S4, adding steel fibers into the second mixture of step S2 and mixing to obtain a third mixture;

[0032] S5, fixing the vinyl ester resin matrix modified composite fiber bar in a mold and pouring the third mixture of step S4 into the mold, and vibrating and compacting, and curing and forming under the set conditions to obtain the energy-saving UHPC concrete.

[0033] By adopting the above technical scheme, the preparation method provided by the application ensures uniform mixing and sufficient reaction of each raw material, forming a dense and uniform concrete structure. This preparation method not only improves the compressive strength, flexural strength and fracture toughness of the concrete, but also significantly reduces the risk of self-shrinkage and early cracking, and improves the corrosion resistance and durability of the concrete. Specifically, the addition of KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar optimizes the microstructure of the concrete, reduces the generation of micro-defects, and improves the density and crack resistance of the concrete. The composite fiber bar forms an effective three-dimensional network structure in the concrete, enhancing the tensile, bending, impact and fatigue resistance of the concrete. At the same time, the use of water reducing agent reduces the water-cement ratio, reduces the transmission channel of corrosive media, and further improves the corrosion resistance of the concrete. These measures effectively solve the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service, prolong the service life of the concrete, and make it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0034] Optionally, the curing and forming conditions in step S5 are: temperature 20-25℃, humidity ≥90%.

[0035] In summary, the present application includes at least one of the following beneficial technical effects:

[0036] 1. The energy-saving UHPC concrete provided by the present application effectively improves the performance of the concrete through the specific proportion of raw materials and the unique preparation method of the vinyl ester resin matrix modified composite fiber reinforcement. In terms of raw materials, Portland cement, as the main cementitious material, cooperates with fly ash to provide basic strength for the concrete. KH550 modified glass beads can improve the internal structure of the concrete and reduce the risk of shrinkage. Silica fume further fills the pores and enhances the density of the concrete. Fine sand, as fine aggregate, together with other ingredients, forms a stable structure. Steel fibers can bridge cracks and transfer stress. The polypropylene fibers and polyvinyl alcohol fibers in the vinyl ester resin matrix modified composite fiber reinforcement bear the tensile force and delay the development of cracks. The vinyl ester resin matrix modification makes the fibers and the concrete matrix have better adhesion, enhancing the anti-cracking effect. In terms of solving the corrosion of fiber reinforced bars and improving durability, when preparing the vinyl ester resin matrix modified composite fiber reinforcement, the organic silicon generated by the reaction of hydrogen silicone oil and KH560 in step A1 provides chemical stability and hydrophobicity. The modified halloysite nanotubes in step A2 and the modified expanded vermiculite in step A3 can form a physical barrier, fill the pores, and reduce the channel of corrosive media. The emulsion prepared by mixing vinyl ester resin, peroxide cyclohexanone dibutyl paste, and cobalt naphthenate styrene liquid in step A4, and the three-dimensional network structure formed by the solidification of vinyl ester resin, ensures the solidification of the initiator and the promoter, isolates the corrosive medium from erosion. At the same time, the water-reducing agent reduces the water-binder ratio and reduces the transmission channel of corrosive media, thereby improving the corrosion resistance of fiber reinforced bars and the durability of concrete. These measures not only significantly improve the compressive strength, flexural strength, and fracture toughness of UHPC, but also effectively reduce the risk of self-shrinkage and early cracking, prolong the service life of the concrete, and make it have a wide application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering, etc.

[0037] 2. When the weight ratio of KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber reinforcement is 1:(2.2-2.8), the uniform distribution and effective combination of KH550 modified glass beads in the vinyl ester resin matrix modified composite fiber reinforcement are ensured. This optimized ratio not only improves the dispersibility and stability of glass beads in the matrix, but also significantly enhances the microstructure of the concrete, reduces the generation of micro-defects, and improves the density and crack resistance of the concrete. The addition of KH550 modified glass beads further optimizes the mechanical properties of the concrete, improves its compressive strength and flexural strength, and the surface modification treatment provides chemical stability and hydrophobicity, effectively reducing the penetration of water and other corrosive media, improving the corrosion resistance and durability of the concrete. This technical solution effectively solves the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service, prolongs the service life of the concrete, and makes it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering, etc.

[0038] 3. The preparation method provided by the present application ensures uniform mixing and sufficient reaction of each raw material, forming a dense and uniform concrete structure. This preparation method not only improves the compressive strength, flexural strength and fracture toughness of the concrete, but also significantly reduces the risk of self-shrinkage and early cracking, improves the corrosion resistance and durability of the concrete. Specifically, the addition of KH550 modified glass microbeads and vinyl ester resin matrix modified composite fiber reinforcement optimizes the microstructure of the concrete, reduces the generation of micro-defects, and improves the density and crack resistance of the concrete. The composite fiber reinforcement forms an effective three-dimensional network structure in the concrete, enhancing the tensile, bending, impact and fatigue resistance of the concrete. At the same time, the use of water reducing agent reduces the water-cement ratio, reduces the transmission channels of corrosive media, and further improves the corrosion resistance of the concrete. These measures effectively solve the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service, prolong the service life of the concrete, and make it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering. DETAILED DESCRIPTION

[0039] The present application will be further described in detail below in conjunction with the examples.

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application will be further described in detail below in conjunction with the examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0041] Ultra-high performance concrete (UHPC) as a kind of cement-based composite material has the characteristics of high strength, high toughness and low porosity, and its mechanical and durability performance far exceeds that of ordinary concrete (NSC) and high performance concrete (HPC), and the compressive strength and flexural strength are very excellent, so it has a wide application in many fields such as building engineering, bridge engineering, tunnel and underground engineering. But UHPC is not perfect, due to its characteristics of low water-binder ratio, high cementitious material content, high active mineral admixture content and low coarse aggregate content, there is a large self-shrinkage during setting and hardening and service period, and the self-shrinkage accounts for more than 80% of the total shrinkage, which greatly increases the possibility of early cracking, and becomes one of the key technical problems limiting the further promotion of UHPC in engineering application. In addition, the shrinkage cracking of concrete allows the penetration of corrosive ions into the interior, significantly reduces the mechanical strength and durability of concrete, accelerates the corrosion and aging of concrete structure, causes the premature deterioration and damage of building structure, and seriously affects the practicability and safety of marine infrastructure. Therefore, in order to solve at least one of the above technical problems, the present application develops a kind of ultra-high performance concrete with small self-shrinkage, low early cracking risk and good corrosion resistance, and provides a kind of energy-saving UHPC concrete and a preparation method thereof. In the first aspect, the application provides an energy-saving UHPC concrete, the concrete comprises the following raw materials by weight: Portland cement 110-150 parts, fly ash 18-35 parts, KH550 modified glass microbeads 20-30 parts, ethylene ester resin matrix modified composite fiber bar 50-75 parts, silica fume 20-38 parts, fine sand 100-175 parts, steel fiber 30-70 parts, water reducing agent 4-9 parts, and water 25-45 parts. The ethylene ester resin matrix modified composite fiber bar is modified by ethylene ester resin matrix on composite fiber. The preparation method of the ethylene ester resin matrix modified composite fiber bar comprises the following steps:

[0042] A1, hydrogen-containing silicone oil and KH560 are mixed in a mass ratio of 1:1, a solvent and a catalyst are added and stirred, and then addition reaction is carried out to obtain silicone, which is prepared for use;

[0043] A2, halloysite nanotubes are mixed with ethanol, then hydrogen-containing silicone oil and ethyl silicate are uniformly mixed to obtain modified halloysite nanotubes;

[0044] A3, hydrogen-containing silicone oil and ethyl silicate are mixed and added dropwise to the surface of expanded vermiculite, then the expanded vermiculite is expanded in a microwave oven, and then stirred in a mixed solution of KOH and anhydrous ethanol, and uniformly mixed to obtain modified expanded vermiculite;

[0045] A4, the ethylene ester resin emulsion is prepared by mixing ethylene ester resin, peroxide cyclohexanone dibutyl paste and cobalt naphthenate styrene liquid in a weight ratio of 100: (1-3): (0.5-1.5);

[0046] A5, the vinyl ester resin emulsion, silicone, modified halloysite nanotube and modified expanded vermiculite are mixed uniformly according to the weight ratio of 100: (5-10): (0.5-1): (0.5-1) to prepare a vinyl ester resin matrix;

[0047] A6, the composite fiber is immersed in the vinyl ester resin matrix, and a vinyl ester resin matrix modified composite fiber rod is prepared by pultrusion, rib forming, curing and cutting. The composite fiber is prepared by mixing polypropylene fibers and polyvinyl alcohol fibers in a weight ratio of 1:1. The energy-saving UHPC concrete provided by the present application effectively improves the performance of the concrete by using specific proportions of raw materials and a unique preparation method of the vinyl ester resin matrix modified composite fiber rod. In terms of raw materials, Portland cement, as the main cementitious material, cooperates with fly ash to provide basic strength for the concrete. KH550 modified glass beads can improve the internal structure of the concrete and reduce the risk of shrinkage. Silica fume further fills the pores and enhances the density of the concrete. Fine sand, as fine aggregate, together with other ingredients, forms a stable structure. Steel fibers can bridge cracks and transfer stress. The polypropylene fibers and polyvinyl alcohol fibers in the vinyl ester resin matrix modified composite fiber rod bear the tensile force and delay the development of cracks. The vinyl ester resin matrix modification makes the fibers and the concrete matrix have better adhesion, enhancing the crack resistance. In terms of solving the corrosion of fiber reinforced bars and improving durability, the silicone generated by the reaction of hydrogen-containing silicone oil and KH560 in step A1 provides chemical stability and hydrophobicity. The modified halloysite nanotubes in step A2 and the modified expanded vermiculite in step A3 can form a physical barrier and fill the pores to reduce the channels of corrosive media. The emulsion prepared by mixing the vinyl ester resin, peroxide cyclohexanone dibutyl paste, and cobalt naphthenate styrene liquid in step A4, the vinyl ester resin solidifies to form a three-dimensional network structure wrapping the fibers, which has chemical corrosion resistance combined with the effects of initiators and accelerators to ensure solidification and isolate corrosive media erosion. At the same time, the water-reducing agent reduces the water-binder ratio and reduces the transmission channels of corrosive media, thereby improving the corrosion resistance of the fiber reinforced bars and the durability of the concrete. These measures not only significantly improve the compressive strength, flexural strength and fracture toughness of UHPC, but also effectively reduce the risk of self-shrinkage and early cracking, prolong the service life of the concrete, and have a wide application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0048] In some embodiments, the weight ratio of halloysite nanotubes, ethanol, hydrogen-containing silicone oil and ethyl silicate in step A2 is 1: (50-100): 1: (2-4).

[0049] Exemplarily, the weight ratio of the halloysite nanotubes, ethanol, hydrogen-containing silicone oil and ethyl silicate in step A2 is 1:50:1:2, 1:75:1:3, 1:100:1:4 or a range consisting of any two of the above values. Based on the above ratio, the present application ensures the uniform dispersion of halloysite nanotubes in ethanol and effective mixing with hydrogen-containing silicone oil and ethyl silicate to form stable modified halloysite nanotubes. This modification process significantly improves the dispersibility and interfacial bonding strength of halloysite nanotubes in the vinyl ester resin matrix, thereby enhancing the mechanical properties and durability of the composite material. The addition of modified halloysite nanotubes not only improves the microstructure of the concrete and reduces the generation of micro-defects, but also improves the density and crack resistance of the concrete, effectively solving the problems of large self-shrinkage and high risk of early cracking of UHPC during setting, hardening and service.

[0050] In some embodiments, the weight ratio of the hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and anhydrous ethanol in the mixed solution in step A3 is (1-3):(3-9):(0.5-1):(50-100).

[0051] Exemplarily, the weight ratio of the hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and anhydrous ethanol in the mixed solution in step A3 is 1:3:0.5:50, 2:7:0.8:80, 3:9:1:100 or a range consisting of any two of the above values. Based on the above ratio, the present application ensures the effective mixing of expanded vermiculite with hydrogen-containing silicone oil and ethyl silicate during surface modification to form stable modified expanded vermiculite. This modification process significantly improves the dispersibility and stability of expanded vermiculite in the vinyl ester resin matrix, thereby not only optimizing the microstructure of the concrete and reducing the generation of micro-defects, but also improving the density and crack resistance of the concrete, effectively solving the problems of large self-shrinkage and high risk of early cracking of UHPC during setting, hardening and service. At the same time, the physical barrier effect of modified expanded vermiculite also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete and prolonging the service life of the concrete.

[0052] In some embodiments, the weight ratio of the composite fiber and the vinyl ester resin matrix in step A6 is (3.5-5):1.

[0053] Exemplarily, the weight ratio of the composite fiber and the vinyl ester resin matrix in step A6 is 3.5:1, 4.5:1, 5:1, or a range consisting of any two of the above values. Based on the above ratio, the present application ensures uniform distribution and sufficient infiltration of the composite fiber in the vinyl ester resin matrix, forming a vinyl ester resin matrix modified composite fiber bar with excellent performance. This optimized ratio not only improves the tensile strength and corrosion resistance of the composite fiber bar, but also significantly enhances the interfacial bonding strength between the composite fiber bar and the concrete matrix, thereby effectively delaying the development and penetration of cracks, and improving the tensile, bending, impact and fatigue resistance of the concrete. The addition of the composite fiber bar further optimizes the microstructure of the concrete, reduces the generation of micro-defects, improves the density and crack resistance of the concrete, and effectively solves the problems of large self-shrinkage and high risk of early cracking of UHPC during setting, hardening and service.

[0054] In some embodiments, the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:(2.2-2.8).

[0055] Exemplarily, the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.2, 1:2.6, 1:2.8, or a range consisting of any two of the above values. Based on the above ratio, when the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:(2.2-2.8), the present application ensures uniform distribution and effective combination of the KH550 modified glass beads in the vinyl ester resin matrix modified composite fiber bar. This optimized ratio not only improves the dispersibility and stability of the glass beads in the matrix, but also significantly enhances the microstructure of the concrete, reduces the generation of micro-defects, and improves the density and crack resistance of the concrete. The addition of the KH550 modified glass beads further optimizes the mechanical properties of the concrete, improves its compressive strength and flexural strength, and the surface modification treatment provides chemical stability and hydrophobicity, effectively reducing the penetration of water and other corrosive media, and improving the corrosion resistance and durability of the concrete. This technical solution effectively solves the problems of large self-shrinkage and high risk of early cracking of UHPC during setting, hardening and service, prolongs the service life of the concrete, and makes it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0056] In some embodiments, the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.5.

[0057] In some embodiments, the diameter of the vinylester resin matrix modified composite fiber tendon is 5-10 mm. This optimized diameter range not only improves the tensile strength and corrosion resistance of the composite fiber tendon, but also significantly enhances the interfacial bonding strength with the concrete matrix, thereby effectively delaying the development and penetration of cracks and improving the stability of the concrete. The moderate diameter of the composite fiber tendon can form an effective three-dimensional network structure in the concrete, further optimizing the microstructure of the concrete, reducing the generation of micro-defects, improving the compactness and crack resistance of the concrete, and effectively solving the problems of large self-shrinkage and high risk of early cracking of UHPC during setting, hardening and service. At the same time, the physical barrier effect of the composite fiber tendon also helps to reduce the penetration of corrosive media, further improving the corrosion resistance and overall performance of the concrete, and prolonging the service life of the concrete.

[0058] In some embodiments, the Portland cement is a common Portland cement of PO42.5 grade.

[0059] In some embodiments, the solvent in step A1 is selected from ethanol; and the catalyst is selected from NaOH.

[0060] In a second aspect, the present application provides a preparation method of energy-saving UHPC concrete, comprising the following steps: S1, weighing each raw material according to the proportion;

[0061] S2, mixing and stirring the Portland cement, fly ash, KH550 modified glass beads, silica fume, fine sand and 75% of water to obtain a first mixture;

[0062] S3, adding the remaining water and water reducing agent into the mixture of step S2 to obtain a second mixture;

[0063] S4, adding steel fiber into the second mixture and mixing to obtain a third mixture;

[0064] S5, fixing the vinyl ester resin matrix modified composite fiber reinforcement in the mold, pouring the third mixture described in step S4 into the mold, vibrating and compacting, and curing and forming under the set conditions to obtain the energy-saving UHPC concrete. The preparation method provided in the application ensures uniform mixing and sufficient reaction of the raw materials, forming a dense and uniform concrete structure. This preparation method not only improves the compressive strength, flexural strength and fracture toughness of the concrete, but also significantly reduces the risk of self-shrinkage and early cracking, and improves the corrosion resistance and durability of the concrete. Specifically, the addition of KH550 modified glass microbeads and the vinyl ester resin matrix modified composite fiber reinforcement optimizes the microstructure of the concrete, reduces the generation of micro-defects, and improves the density and crack resistance of the concrete. The vinyl ester resin matrix modified composite fiber reinforcement forms an effective three-dimensional network structure in the concrete, enhancing the compressive strength of the concrete and reducing the early shrinkage rate and cracking. At the same time, the use of water reducing agent reduces the water-binder ratio, reduces the transmission channel of corrosive media, and further improves the corrosion resistance of the concrete. These measures effectively solve the problems of large self-shrinkage and high risk of early cracking of UHPC during setting and hardening and service, prolong the service life of the concrete, and make it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0065] In some embodiments, the curing and forming conditions in step S5 are: temperature 20-25℃, humidity ≥90%. Specific embodiments

[0066] All chemical components used in the application are commercially available unless otherwise specified.

[0067] Preparation Examples 1-3 provide a vinyl ester resin matrix modified composite fiber reinforcement.

[0068] Preparation Example 1

[0069] The preparation example provides a vinyl ester resin matrix modified composite fiber reinforcement, and the preparation method comprises the following steps: A1, mixing hydrogen-containing silicone oil and KH560 in a mass ratio of 1:1 with ethanol as a solvent, and under the catalytic action of NaOH, using a magnetic stirrer (200 r / min) to react at room temperature for 8 h to obtain silicone, which is ready for use;

[0070] A2, mixing halloysite nanotubes with ethanol, then mixing hydrogen-containing silicone oil and ethyl silicate uniformly to obtain modified halloysite nanotubes;

[0071] A3, mixing hydrogen-containing silicone oil and ethyl silicate, and adding dropwise to the surface of expanded vermiculite, expanding in a microwave oven, and then stirring in a mixed solution of KOH and anhydrous ethanol (KOH and anhydrous ethanol) to obtain modified expanded vermiculite;

[0072] A4, the vinyl ester resin, peroxide cyclohexanone dibutyl paste, naphthenic acid cobalt styrene liquid are mixed according to the weight ratio of 100:1:0.5 to prepare a vinyl ester resin emulsion;

[0073] A5, the vinyl ester resin emulsion in step A4, the organic silicon in step A1, the modified halloysite nanotube in step A2 and the modified expanded vermiculite in step A3 are uniformly mixed according to the weight ratio of 100:5:0.5:0.5 to prepare a vinyl ester resin matrix;

[0074] A6, the composite fiber is immersed in the vinyl ester resin matrix in step A5, pultruded (pultrusion rate is 0.8 m / min), rib-shaped, cured, and cut to prepare a vinyl ester resin matrix modified composite fiber rod;

[0075] The composite fiber in step A6 is prepared by mixing polypropylene fiber and polyvinyl alcohol fiber according to the weight ratio of 1:1.

[0076] The weight ratio of halloysite nanotube, ethanol, hydrogen-containing silicone oil and ethyl silicate in step A2 is 1:50:1:2. The weight ratio of hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and anhydrous ethanol mixed solution in step A3 is 1:3:0.5:50. The weight ratio of composite fiber and vinyl ester resin matrix in step A6 is 3.5:1. The diameter of the vinyl ester resin matrix modified composite fiber rod is 5-10mm.

[0077] Preparation Example 2

[0078] The preparation example provides a vinyl ester resin matrix modified composite fiber rod, and the preparation method comprises the following steps: A1, hydrogen-containing silicone oil and KH560 are mixed according to the mass ratio of 1:1, ethanol is used as a solvent, under the catalysis of NaOH, after constant temperature reaction for 8h by using a magnetic stirrer (200 r / min), an organic silicon is prepared for standby;

[0079] A2, halloysite nanotubes are mixed with ethanol, then hydrogen-containing silicone oil and ethyl silicate are uniformly mixed to prepare modified halloysite nanotubes;

[0080] A3, hydrogen-containing silicone oil and ethyl silicate are mixed and added dropwise to the surface of expanded vermiculite, then the expanded vermiculite is expanded in a microwave oven, and then stirred in a mixed solution of KOH and anhydrous ethanol to prepare modified expanded vermiculite;

[0081] A4, the vinyl ester resin, peroxide cyclohexanone dibutyl paste, naphthenic acid cobalt styrene liquid are mixed according to the weight ratio of 100:1:1 to prepare a vinyl ester resin emulsion;

[0082] A5, the vinyl ester resin emulsion in step A4, the organic silicon in step A1, the modified halloysite nanotube in step A2 and the modified expanded vermiculite in step A3 are mixed uniformly according to the weight ratio of 100:8:0.8:0.9 to prepare a vinyl ester resin matrix;

[0083] A6, the composite fiber is dipped in the vinyl ester resin matrix in step A5, and is drawn (the drawing rate is 0.8 m / min), rib-shaped, cured, and cut to prepare a vinyl ester resin matrix modified composite fiber rod;

[0084] The composite fiber in step A6 is prepared by mixing polypropylene fibers and polyvinyl alcohol fibers according to the weight ratio of 1:1.

[0085] The weight ratio of the halloysite nanotube, ethanol, hydrogen-containing silicone oil and ethyl silicate in step A2 is 1:85:1:3. The weight ratio of the hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and the mixed solution of anhydrous ethanol in step A3 is 2:7:0.8:85. The weight ratio of the composite fiber and the vinyl ester resin matrix in step A6 is 4.5:1. The diameter of the vinyl ester resin matrix modified composite fiber rod is 5-10 mm.

[0086] Preparation Example 3

[0087] The present preparation example provides a vinyl ester resin matrix modified composite fiber rod, and the preparation method comprises the following steps: A1, hydrogen-containing silicone oil and KH560 are mixed according to the mass ratio of 1:1, ethanol is used as a solvent, under the catalysis of NaOH, after 8 h of normal temperature reaction by using a magnetic stirrer (200 r / min), organic silicon is prepared for standby use;

[0088] A2, halloysite nanotubes are mixed with ethanol, and then hydrogen-containing silicone oil and ethyl silicate are uniformly mixed to prepare modified halloysite nanotubes;

[0089] A3, hydrogen-containing silicone oil and ethyl silicate are mixed and added dropwise to the surface of expanded vermiculite, and then the expanded vermiculite is expanded in a microwave oven and stirred in a mixed solution of KOH and anhydrous ethanol, and then uniformly mixed to prepare modified expanded vermiculite;

[0090] A4, vinyl ester resin, peroxide cyclohexanone dibutyl paste and cobalt naphthenate styrene solution are mixed according to the weight ratio of 100:1:1.5 to prepare a vinyl ester resin emulsion;

[0091] A5, the vinyl ester resin emulsion in step A4, the organic silicon in step A1, the modified halloysite nanotube in step A2 and the modified expanded vermiculite in step A3 are mixed uniformly according to the weight ratio of 100:8:0.8:0.9 to prepare a vinyl ester resin matrix;

[0092] A6, the composite fiber is impregnated in the vinyl ester resin matrix in step A5, pultruded (pultrusion rate is 0.8 m / min), rib-shaped, cured, and cut to obtain a vinyl ester resin matrix modified composite fiber rod;

[0093] The composite fiber in step A6 is prepared by mixing polypropylene fibers and polyvinyl alcohol fibers at a weight ratio of 1:1.

[0094] The weight ratio of halloysite nanotubes, ethanol, hydrogen-containing silicone oil, and ethyl silicate in step A2 is 1:100:1:4. The weight ratio of the mixed solution of hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH, and anhydrous ethanol in step A3 is 3:9:1:100. The weight ratio of the composite fiber and the vinyl ester resin matrix in step A6 is 5:1. The diameter of the vinyl ester resin matrix modified composite fiber rod is 5-10 mm.

[0095] Example 1

[0096] The energy-saving UHPC concrete provided in this embodiment includes the following raw materials by weight: Portland cement 110 parts, fly ash 18 parts, KH550 modified glass beads 28 parts, vinyl ester resin matrix modified composite fiber rod 70 parts, silica fume 20 parts, fine sand 100 parts, steel fiber 30 parts, water reducing agent 4 parts, and water 25 parts.

[0097] The vinyl ester resin matrix modified composite fiber rod in this embodiment is prepared by the vinyl ester resin matrix prepared in Preparation Example 1.

[0098] The Portland cement in this embodiment is a PO42.5 grade ordinary Portland cement.

[0099] The water reducing agent used in this embodiment is a polycarboxylic acid water reducing agent with a solid content of 30%.

[0100] The KH550 modified glass beads are prepared by mixing KH550, ethanol, and glass beads at a weight ratio of 1:50:10. The method is as follows: dissolve KH550 in ethanol, add glass beads, and mix to obtain a mixture; stir the mixture uniformly to ensure that KH550 is evenly attached to the surface of the glass beads;

[0101] Dry to remove excess solvent and moisture, and cool to room temperature to obtain the KH550 modified glass beads.

[0102] The energy-saving UHPC concrete preparation method provided in this embodiment includes the following steps:

[0103] S1, weigh each raw material according to the proportion;

[0104] S2, mixing and stirring silicate cement, fly ash, KH550 modified glass beads, silica fume, fine sand and 75% water to prepare a first mixture;

[0105] S3, adding the remaining water and water reducing agent to the mixture in step S2 to prepare a second mixture;

[0106] S4, adding steel fibers to the second mixture and mixing, and after stirring, preparing a third mixture;

[0107] S5, fixing the vinyl ester resin matrix modified composite fiber bar in the mold, and pouring the third mixture in step S4 into the mold, and vibrating and compacting, and after curing and forming at a temperature of 20-25℃ and a humidity of ≥95%, an energy-saving UHPC concrete is prepared.

[0108] Example 2

[0109] The difference between this example and Example 1 is that in the preparation of the energy-saving UHPC concrete, the total weight of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 98 parts, and the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.2.

[0110] Example 3

[0111] The difference between this example and Example 1 is that in the preparation of the energy-saving UHPC concrete, the total weight of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 98 parts, and the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.6.

[0112] Example 4

[0113] The difference between this example and Example 1 is that in the preparation of the energy-saving UHPC concrete, the total weight of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 98 parts, and the weight ratio of the KH550 modified glass beads and the vinyl ester resin matrix modified composite fiber bar is 1:2.8.

[0114] Comparative Examples 1-6

[0115] Comparative Example 1

[0116] The difference between this example and Example 1 is that in the preparation of the energy-saving UHPC concrete, an equal amount of KH550 modified glass beads is used to replace the vinyl ester resin matrix modified composite fiber bar.

[0117] Comparative Example 2

[0118] The difference between the present comparative example and Example 1 is that, in the preparation of the energy-saving UHPC concrete, an equal amount of composite fiber reinforced bars modified by a vinyl ester resin matrix is used to replace the KH550 modified glass beads.

[0119] Comparative Example 3

[0120] The difference between the present comparative example and Example 1 is that, in the preparation of the energy-saving UHPC concrete, an equal amount of composite fiber is used to replace the composite fiber reinforced bars modified by a vinyl ester resin matrix.

[0121] Comparative Example 4

[0122] The difference between the present comparative example and Example 1 is that, in the preparation of the energy-saving UHPC concrete, an equal amount of polypropylene fiber is used to replace the composite fiber.

[0123] Comparative Example 5

[0124] The difference between the present comparative example and Example 1 is that, in the preparation of the energy-saving UHPC concrete, an equal amount of polyvinyl alcohol fiber is used to replace the composite fiber.

[0125] Comparative Example 6

[0126] The difference between the present comparative example and Example 1 is that, in the preparation of the energy-saving UHPC concrete, an equal amount of unmodified glass beads is used to replace the KH550 modified glass beads.

[0127] Controlled concrete (reference concrete): The controlled concrete is a concrete that does not add composite fiber reinforced bars modified by a vinyl ester resin matrix in the preparation of the energy-saving UHPC concrete.

[0128] Experimental detection:

[0129] Compressive strength test: The test is carried out in accordance with GB / T 17671-2021.

[0130] Shrinkage test: The shrinkage test is carried out in accordance with GB / T 50082-2009 "Standard for Testing Methods for Long-term Performance and Durability of Ordinary Concrete" (the concrete sample is wrapped with cling film on the surface, and then wrapped and sealed with self-adhesive aluminum foil, and the sealed test piece is placed in an environment with a temperature of 20±1℃ and a relative humidity of 95% for curing for 28 days).

[0131] Cracking resistance test: According to Appendix A in T / CECS10001-2017 "Anti-cracking and Anti-permeability composite materials for concrete", the crack reduction coefficient in the early cracking performance of the concrete is determined; wherein the tested concrete is the concrete sample prepared in Examples 1-4 and Comparative Examples 1-6.

[0132] Corrosion resistance coefficient: refer to GB / T50082 concrete durability test method, the prepared concrete test block: 100x100x100mm 3 After 28 days of curing at 20±2°C, 95% humidity standard conditions, immerse in the simulated natural saline water composite salt water prepared by 1000ml pure water, add 30g of anhydrous sodium sulfate, 1.65g of sodium chloride and 17.6g of magnesium chloride heptahydrate for 6 hours, and then dry for 4 hours as a cycle. The ratio of the compressive strength after 100 cycles to the compressive strength before durability test. Specifically, before the durability test (i.e. after 28 days of curing), the initial compressive strength of the concrete test block is measured, denoted as R0. After 100 corrosion cycles, the compressive strength of the concrete test block is measured again, denoted as Rf. The corrosion resistance coefficient K is calculated as follows: K = Rf / R0

[0133] The experimental test results of examples 1-4 and comparative examples 1-6 are shown in Table 1.

[0134] Table 1- Experimental test results of examples 1-4 and comparative examples 1-6

[0135]

[0136] Result analysis: the difference between examples 2-4 and example 1 is that the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforcement remains unchanged when preparing energy-saving UHPC concrete, but the weight ratio between the two changes. According to the experimental test results in Table 1, when the weight ratio of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforcement is 1:2.5, the prepared energy-saving UHPC concrete exhibits higher compressive strength, lower shrinkage and better corrosion resistance.

[0137] The difference between Comparative Example 1 and Example 1 is that, in the preparation of energy-saving UHPC concrete, an equal amount of KH550 modified glass microbeads is used to replace the vinyl ester resin matrix modified composite fiber bar. The results show that, although the concrete has a certain compressive strength, the shrinkage rate is high and the corrosion resistance is poor. The difference between Comparative Example 2 and Example 1 is that, in the preparation of energy-saving UHPC concrete, an equal amount of vinyl ester resin matrix modified composite fiber bar is used to replace KH550 modified glass microbeads. The results show that, although the concrete has a certain compressive strength, the shrinkage rate and corrosion resistance are not as good as Example 1. According to the experimental detection data of Comparative Examples 1-2 and Example 1, when KH550 modified glass microbeads and vinyl ester resin matrix modified composite fiber bar are used together, the compressive strength of energy-saving UHPC concrete can be significantly improved, the shrinkage rate can be reduced, and the corrosion resistance can be enhanced, making it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering. The reason is that KH550 modified glass microbeads can optimize the microstructure of concrete, reduce the shrinkage risk, and improve the compactness; while the vinyl ester resin matrix modified composite fiber bar can significantly enhance the mechanical properties and crack resistance of concrete through its three-dimensional network structure and excellent bonding performance, and provide additional corrosion resistance. The use of these two materials together achieves a complementary effect, which comprehensively improves the overall performance of the concrete.

[0138] The difference between Comparative Example 3 and Example 1 is that, in the preparation of energy-saving UHPC concrete, an equal amount of composite fiber is used to replace the vinyl ester resin matrix modified composite fiber bar. According to the experimental detection results in Table 1, when unmodified composite fiber is used to prepare UHPC concrete, the concrete will have a high shrinkage rate and poor corrosion resistance, and the improvement of compressive strength is not significant. The reason is that unmodified composite fiber has poor dispersibility and interfacial compatibility in concrete, which cannot form a good bond with the concrete matrix, thereby affecting the overall performance of the concrete. Specifically, unmodified composite fiber is not uniformly dispersed in concrete, which can easily form local aggregation, leading to uneven stress distribution in the concrete, increasing the risk of self-shrinkage and early cracking. At the same time, the surface activity of unmodified composite fiber is low, which cannot effectively form a physical barrier to reduce the penetration of corrosive media, resulting in a decrease in the corrosion resistance of the concrete. In addition, the interfacial bonding force between unmodified composite fiber and the concrete matrix is weak, which cannot effectively transfer stress, thereby limiting the improvement of the compressive strength of the concrete. In contrast, the vinyl ester resin matrix modified composite fiber bar, through the modification treatment of vinyl ester resin, significantly improves the interfacial bonding force between the fiber and the concrete matrix, optimizes the microstructure of the concrete, thereby significantly improving the compressive strength of the concrete, reducing the shrinkage rate and enhancing the corrosion resistance.

[0139] Comparative Example 4 differs from Example 1 in that polypropylene fibers are used instead of composite fibers in the preparation of energy-saving UHPC concrete; Comparative Example 5 differs from Example 1 in that polyvinyl alcohol fibers are used instead of composite fibers. According to the experimental test results of Table 1 and Comparative Examples 4-5, when polypropylene fibers and polyvinyl alcohol fibers are used together in the preparation of energy-saving UHPC concrete, the comprehensive performance of the energy-saving UHPC concrete can be significantly improved. The reason is that polypropylene fibers have high tensile strength and good dispersibility, which can form an effective stress transfer network in the concrete to improve the compressive strength of the concrete; and polyvinyl alcohol fibers have good toughness and adhesion, which can effectively inhibit the expansion of cracks and improve the crack resistance and impermeability of the concrete. The complementary advantages of the two fibers not only significantly improve the mechanical properties of the concrete, but also effectively reduce the shrinkage of the concrete, reduce the risk of self-shrinkage and early cracking, and enhance the corrosion resistance of the concrete, making it have a wider application prospect in various fields such as building engineering, bridge engineering, tunnel and underground engineering.

[0140] Comparative Example 6 differs from Example 1 in that unmodified glass microbeads are used instead of KH550 modified glass microbeads in the preparation of energy-saving UHPC concrete. According to the experimental test results of Table 1, when unmodified glass microbeads are used, the compressive strength of the concrete is reduced to some extent, and the shrinkage is relatively high. The reason may be that the dispersibility and interfacial compatibility of unmodified glass microbeads in the concrete are poor, which cannot effectively improve the internal structure and micro-pore distribution of the concrete, thereby affecting the compactness and mechanical properties of the concrete. In addition, the surface activity of unmodified glass microbeads is low, which cannot effectively reduce the self-shrinkage of the concrete, resulting in more micro-cracks in the concrete during the hardening process, increasing the shrinkage. In contrast, KH550 modified glass microbeads improve the interfacial bonding between the concrete matrix and the microbeads through surface modification, optimize the microstructure of the concrete, and significantly improve the compressive strength and crack resistance of the concrete, thereby reducing the shrinkage. These improvements make the energy-saving UHPC concrete have better comprehensive performance and longer service life in practical applications.

[0141] Examples 5-6

[0142] Examples 5-6 differ from Example 1 in that the weight fractions of some components are different in the preparation of energy-saving UHPC concrete, see Table 2 for the difference.

[0143] Table 2 - Difference between Examples 5-6 and Example 2

[0144]

[0145] The experimental test results of Examples 5-6 are shown in Table 3.

[0146] Table 3 - Experimental test results table of Example 5-6

[0147]

[0148] Result analysis: The difference between Example 5-6 and Example 1 is that the weight fractions of some components are different when preparing energy-saving UHPC concrete. According to the experimental test results in Table 3, the comprehensive performance of the energy-saving UHPC concrete prepared from Example 5 is better.

[0149] Example 7

[0150] The difference between Example 7-11 and Example 5 is that, on the premise that the weight ratio of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforced bars is 1:2.5, the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforced bars in the energy-saving UHPC concrete is changed, and the better weight ratio is selected.

[0151] In Example 5, the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforced bars is 95 parts, and the total weight of energy-saving UHPC concrete is 526 parts.

[0152] Therefore, it is not difficult to conclude that in Example 5, the proportion of KH550 modified glass beads (referred to as variable 1) and vinyl ester resin matrix modified composite fiber reinforced bars (referred to as variable 2) in energy-saving UHPC concrete (referred to as matrix) is 18.63%.

[0153] The difference between Example 7-11 and Example 5 is shown in Table 4.

[0154] Proportion = (variable 1 + variable 2) / total weight of matrix * 100%.

[0155] Table 4 - Difference between Example 7-11 and Example 5

[0156]

[0157] The experimental test results of Example 7-11 are shown in Table 5.

[0158] Table 5 - Experimental test results table of Example 7-11

[0159]

[0160] Result analysis: the difference between examples 7-11 and example 5 is that the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforcement in the energy-saving UHPC concrete is different. According to the experimental test results in table 5, when the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforcement in the energy-saving UHPC concrete is 19-24.94%, the comprehensive performance of the prepared energy-saving UHPC concrete is better, and when the total weight of KH550 modified glass beads and vinyl ester resin matrix modified composite fiber reinforcement in the energy-saving UHPC concrete is 20.92%, the comprehensive performance of the prepared energy-saving UHPC concrete is best. When the proportion is too high or too low, the comprehensive performance decreases.

[0161] Examples 12-13 Example 12

[0162] The difference between this example and example 5 is that the preparation parameters of the vinyl ester resin matrix modified composite fiber reinforcement used in the preparation of energy-saving UHPC concrete are different. The vinyl ester resin matrix modified composite fiber reinforcement in this example is prepared by preparation example 2.

[0163] Example 13

[0164] The difference between this example and example 5 is that the preparation parameters of the vinyl ester resin matrix modified composite fiber reinforcement used in the preparation of energy-saving UHPC concrete are different. The vinyl ester resin matrix modified composite fiber reinforcement in this example is prepared by preparation example 3. The experimental test results of examples 12-13 are shown in table 6.

[0165] Table 6- experimental test results of examples 12-13

[0166]

[0167] Result analysis: the difference between examples 12-13 and example 5 is that the preparation parameters of the vinyl ester resin matrix modified composite fiber reinforcement used in the preparation of energy-saving UHPC concrete are different. According to the experimental test results in table 6, the energy-saving UHPC concrete prepared by example 12 has better comprehensive performance.

[0168] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, any equivalent changes made on the basis of the structure, shape, principle of the present application shall be covered within the protection scope of the present application.

Claims

1. An energy-saving UHPC concrete, characterized in that, The concrete comprises the following raw materials by weight: 110-150 parts silicate cement, 18-35 parts fly ash, 20-30 parts KH550 modified glass microspheres, 50-75 parts vinyl ester resin matrix modified composite fiber reinforcement, 20-38 parts silica fume, 100-175 parts fine sand, 30-70 parts steel fiber, 4-9 parts water-reducing agent, and 25-45 parts water; The vinyl ester resin matrix modified composite fiber reinforcement is prepared by modifying composite fibers with a vinyl ester resin matrix; The preparation method of the vinyl ester resin matrix modified composite fiber reinforcement includes the following steps: A1. Mix hydrogen-containing silicone oil and KH560 at a mass ratio of 1:1, add solvent and catalyst and stir to carry out addition reaction to obtain organosilicon for later use. A2. Mix halloysite nanotubes with ethanol, then add hydrogen-containing silicone oil and ethyl silicate and mix well to obtain modified halloysite nanotubes. A3. Mix hydrogen-containing silicone oil with ethyl silicate and drop it onto the surface of expanded vermiculite. Expand the vermiculite in a microwave oven and then place it in a mixed solution of KOH and anhydrous ethanol and stir until well mixed to obtain modified expanded vermiculite. A4. Mix vinyl ester resin, dibutyl cyclohexanone peroxide paste, and cobalt naphthenate styrene solution in a weight ratio of 100:(1-3):(0.5-1.5) to prepare a vinyl ester resin emulsion. A5. The vinyl ester resin emulsion described in step A4, the organosilicon described in step A1, the modified halloysite nanotubes described in step A2, and the modified expanded vermiculite described in step A3 are mixed evenly in a weight ratio of 100:(5-10):(0.5-1):(0.5-1) to obtain a vinyl ester resin matrix. A6. The composite fiber is impregnated in the vinyl ester resin matrix described in step A5, and then pultruded, wound into ribs, cured, and cut to obtain the vinyl ester resin matrix modified composite fiber rib. The composite fiber described in step A6 is prepared by mixing polypropylene fiber and polyvinyl alcohol fiber in a weight ratio of 1:

1.

2. The energy-saving UHPC concrete according to claim 1, characterized in that, In step A2, the weight ratio of halloysite nanotubes, ethanol, hydrogen-containing silicone oil, and ethyl silicate is 1:(50-100):1:(2-4).

3. The energy-saving UHPC concrete according to claim 1, characterized in that, The weight ratio of the mixed solution of hydrogen-containing silicone oil, ethyl silicate, expanded vermiculite, KOH and anhydrous ethanol in step A3 is (1-3):(3-9):(0.5-1):(50-100).

4. The energy-saving UHPC concrete according to claim 1, characterized in that, In step A6, the weight ratio of the composite fiber to the vinyl ester resin matrix is ​​(3.5-5):

1.

5. The energy-saving UHPC concrete according to claim 1, characterized in that, The weight ratio of the KH550 modified glass microspheres to the vinyl ester resin matrix modified composite fiber reinforcement is 1:(2.2-2.8).

6. The energy-saving UHPC concrete according to claim 5, characterized in that, The weight ratio of the KH550 modified glass microspheres to the vinyl ester resin matrix modified composite fiber reinforcement is 1:2.

5.

7. The energy-saving UHPC concrete according to claim 1, characterized in that, The diameter of the vinyl ester resin matrix modified composite fiber reinforcement is 5-10 mm.

8. The energy-saving UHPC concrete according to claim 1, characterized in that, The silicate cement is PO42.5 grade ordinary silicate cement.

9. The energy-saving UHPC concrete according to claim 1, characterized in that, The solvent in step A1 is selected from ethanol; the catalyst is selected from NaOH.

10. A method for preparing energy-saving UHPC concrete according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Weigh each raw material according to the proportions; S2. Silicate cement, fly ash, KH550 modified glass microspheres, silica fume, fine sand and 75% water are mixed and stirred to prepare the first mixture; S3. Add the remaining water and water-reducing agent to the first mixture in step S2 to obtain the second mixture; S4. Add steel fibers to the second mixture in step S2 and mix them. After stirring, a third mixture is obtained. S5. Fix the vinyl ester resin matrix modified composite fiber reinforcement onto the mold, pour the third mixture described in step S4 into the mold, vibrate and compact it, and cure it under the set conditions to obtain the energy-saving UHPC concrete.

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