Lightweight concrete for bridge deck pavement and preparation method thereof

Abstract

The invention relates to the technical field of concrete, and particularly discloses lightweight concrete for bridge deck pavement and a preparation method thereof, the lightweight concrete comprises the following raw materials by weight: 20-40 parts of a lightweight high-strength material, 5-10 parts of alumina fiber, 80-100 parts of Portland cement, 120-200 parts of quartz sand, 10-20 parts of silica fume, 0.6-3 parts of a water reducer, and 20-45 parts of water; the light high-strength material comprises 13-26 parts of hollow glass beads, 4-8 parts of corundum powder and 30-50 parts of an epoxy adhesive solution; the preparation method comprises the following steps: S1, mixing the light high-strength material with alumina fibers to obtain an aluminum fiber light high-strength material; and S2, adding Portland cement, quartz sand, silica fume and a water reducing agent into water, mixing and stirring, then adding the aluminum fiber lightweight high-strength material, and continuously stirring to obtain the lightweight concrete for bridge deck pavement. The lightweight concrete has the advantages of light weight, uniform overall compactness and high compressive strength.

Description

Technical Field

[0001] This application relates to the technical field of concrete, and more specifically, it relates to a lightweight concrete for bridge deck paving and a preparation method thereof. Background Art

[0002] In bridge construction, because the loads borne by bridges are relatively large and high strength is required to ensure the firmness and safety of the bridge structure, compared with ordinary concrete, high-quality cement, high-grade mineral admixtures, and high-quality aggregates are used in bridge concrete, making bridge concrete have higher density and durability; in terms of strength, bridge concrete contains more cement and a higher total amount of admixtures than ordinary concrete, so bridge concrete is stronger than ordinary concrete.

[0003] Chinese invention patent with the publication number CN109206095B discloses a micro-expansion ultra-high performance concrete, which includes the following components and their weight ratios: 100 parts of portland cement; 10 - 55 parts of mineral admixture; 20 - 60 parts of silica fume; 10 - 35 parts of volume stabilizer; 150 - 250 parts of quartz sand; 15 - 40 parts of steel fiber; 2.0 - 5.0 parts of high-dispersion low-viscosity water reducer; 30 - 45 parts of water; due to the addition of the mineral admixture, the overall performance of the concrete is significantly improved, the fluidity of the concrete is greatly increased, and it has high durability and high pumpability; and the micro-expansion ultra-high performance of this concrete enables the concrete to form a non-prestressed simply supported to continuous system, and can also meet the requirements of its own bearing capacity, interface bonding, micro-expansion property and durability, effectively improving the construction efficiency of non-prestressed simply supported to continuous system bridges.

[0004] The above-mentioned concrete for bridges greatly enhances the compressive strength of the concrete due to the addition of mineral admixtures, but there is a problem that while enhancing the strength of the concrete, the weight of the concrete is also increased. Summary of the Invention

[0005] In order to solve the above-mentioned disadvantages that the weight of the concrete increases while the compressive strength is increased, this application provides a lightweight concrete for bridge deck paving and a preparation method thereof.

[0006] In the first aspect, this application provides a lightweight concrete for bridge deck paving, and the following technical solution is adopted: A lightweight concrete for bridge deck paving, comprising the following raw materials in parts by weight: 20-40 parts of lightweight high-strength materials, 5-10 parts of alumina fibers, 80-100 parts of portland cement, 120-200 parts of quartz sand, 10-20 parts of silica fume, 0.6-3 parts of water reducer, and 20-45 parts of water; based on the parts by weight of the lightweight high-strength materials, the lightweight high-strength materials include 13-26 parts of hollow glass microspheres, 4-8 parts of corundum powder, and 30-50 parts of epoxy adhesive solution.

[0007] By adopting the above technical solution, lightweight high-strength materials and alumina fibers are added to traditional concrete, aiming to make the lightweight concrete lighter in weight while increasing its strength; the lightweight high-strength materials account for a relatively large proportion in the lightweight concrete and are the main components. The hollow glass microspheres in the lightweight high-strength materials are hollow inside, with a mass 1 / 3 - 1 / 5 times that of C50 concrete, and the compressive strength of the hollow glass microspheres can reach the compressive strength of C50 concrete, and also provide heat insulation for the lightweight concrete; the corundum powder in this application is to further enhance the compressive strength of the lightweight high-strength materials. The compressive strength of C50 concrete is 50 - 65 MPa, while the compressive strength of corundum powder can reach 300 - 400 MPa. The corundum powder is adhered to the surface of the hollow glass microspheres through an epoxy resin adhesive, enabling the corundum powder to exert its high compressive strength performance while integrating with the hollow glass microspheres to form a coated structure of hollow glass microspheres @ corundum powder. The corundum powder can protect the hollow glass microspheres, enabling the hollow glass microspheres to still maintain their functions of making the lightweight concrete lighter in weight and providing heat insulation under extreme external environments; one end of the alumina fibers is adhered to the lightweight high-strength materials through an epoxy adhesive solution, and the remaining part is bonded to other components of the lightweight concrete, ensuring that the lightweight concrete has a relatively uniform overall density, high and uniform compressive strength, and is difficult to crack while reducing its weight.

[0008] When the bridge construction is not fully completed, the bridge concrete will release hydration heat, and in the external environment, the bridge concrete will encounter extremely cold or extremely hot weather. This requires that the newly added substances in traditional bridge concrete can meet the thermal expansion and contraction performance of traditional bridge concrete; the thermal expansion coefficient of hollow glass microspheres is generally about 4.5×10 -6 / °C, the thermal expansion coefficient of concrete is generally about 1.0×10 -5 / °C, while the thermal expansion coefficient of corundum powder is generally about 8.6×10 -6 / °C, and the thermal expansion coefficient of alumina fibers is generally also about 8.6×10 -6At around [[ID=]], the coefficient of thermal expansion of alumina fiber is exactly between that of hollow glass microspheres and concrete. When lightweight concrete encounters different hot and cold temperatures, the coated connection structure of hollow glass microspheres @ corundum powder - alumina fiber can prevent lightweight concrete from cracking and extend the service life of lightweight concrete.

[0009] Optionally, the hollow glass microspheres are HGS series hollow glass microspheres.

[0010] By adopting the above technical solution, compared with other series of hollow glass microspheres, the HGS series of hollow glass microspheres have a smaller density than ordinary glass microspheres, which makes it have a significant effect in reducing weight; poor thermal conductivity, which helps to improve the heat preservation and heat insulation performance; good compressive strength, and can remain stable under high-pressure environments.

[0011] Optionally, the particle size of the hollow glass microspheres is 30 - 50 μm.

[0012] By adopting the above technical solution, the hollow glass microspheres with a particle size of 30 - 50 μm can not only ensure uniform distribution in lightweight concrete, but also achieve sufficient compressive strength, and are also convenient for the subsequent coating of corundum powder and partial connection of alumina fiber. It is convenient to connect one end of the alumina fiber after forming the coated structure of hollow glass microspheres @ corundum powder, so that under the condition of ensuring lightweight, the density, compressive strength and crack resistance of lightweight concrete are enhanced.

[0013] Optionally, the corundum powder is nano-sized white corundum powder.

[0014] By adopting the above technical solution, while having the excellent properties of corundum powder, the nano-sized white corundum powder has a nano-sized dimension and can densely coat the surface of hollow glass microspheres with a particle size of 30 - 50 μm. And because the hollow glass microspheres with a particle size of 30 - 50 μm are hydrophobic, the hollow glass microspheres and the nano-sized white corundum powder will not separate due to subsequent water exposure. That is, the nano-sized white corundum powder improves the compressive strength of lightweight concrete through its own performance and also maintains the stability of the hollow glass microspheres in lightweight concrete, extending the service life of lightweight concrete.

[0015] Optionally, the length of the alumina fiber is 20 - 50 mm.

[0016] By adopting the above technical solution, the alumina fiber with a length of 20 - 50 mm not only has the same coefficient of thermal expansion as the nano-sized white corundum powder, but also because the length of the alumina fiber is much larger than the diameter of the hollow glass microspheres. Therefore, the alumina fiber can not only connect with the coated structure of hollow glass microspheres @ corundum powder, but also bond with other components of lightweight concrete, ensuring that the overall density of lightweight concrete is relatively uniform, the compressive strength is uniform, and it is difficult to generate cracks.

[0017] Optionally, the epoxy adhesive solution is an epoxy adhesive ethanol solution.

[0018] By adopting the above technical solution, ethanol is used as the solvent of the epoxy adhesive. Since ethanol can dissolve the epoxy adhesive, the epoxy adhesive can be evenly distributed in ethanol, facilitating the uniform adhesion of the epoxy resin adhesive on the surface of hollow glass microspheres by spraying; moreover, since ethanol is easy to volatilize, after ethanol volatilizes, the epoxy adhesive can adhere more tightly to the surface of hollow glass microspheres, forming a tightly coated structure of hollow glass microspheres @ corundum powder.

[0019] Second, the present application provides a preparation method of lightweight concrete for bridge deck paving, adopting the following technical solution: A preparation method of lightweight concrete for bridge deck paving, comprising the following steps: Step S1: Mix and stir the lightweight and high-strength material and alumina fiber in water at 40 - 60 °C at a speed of 15 - 30 rpm for 18 - 26 h, and obtain aluminum fiber lightweight and high-strength material after centrifuging to remove water; Step S2: Add portland cement, quartz sand, silica fume and water reducer to water, mix and stir at a speed of 10 - 20 rpm at room temperature for 10 - 30 min, then add the aluminum fiber lightweight and high-strength material, and continue to mix and stir at a speed of 10 - 20 rpm for 30 - 60 min to obtain a lightweight concrete for bridge deck paving.

[0020] By adopting the above technical solution, in step S1, since the epoxy adhesive in the lightweight and high-strength material is insoluble in water, it can tightly adhere to the surface of hollow glass microspheres. The epoxy adhesive can bond alumina fiber. Under suitable temperature conditions, the epoxy adhesive gradually completely solidifies in water to obtain a lightweight and high-strength material connecting alumina fiber, namely aluminum fiber lightweight and high-strength material; in step S2, adding the aluminum fiber lightweight and high-strength material to the mixed traditional concrete slurry and continuing to mix, the aluminum fiber lightweight and high-strength material can be evenly distributed in the traditional concrete slurry to obtain a lightweight concrete for bridge deck paving.

[0021] Optionally, the preparation method of the lightweight and high-strength material comprises the following steps: Step Sa: Add nanoscale white corundum powder to the epoxy adhesive solution, stir at a speed of 100 - 150 rpm for 10 - 20 min to obtain corundum glue mucus; Step Sb: Spray the corundum glue mucus on the surface of hollow glass microspheres, and then air-dry at a temperature of 40 - 60 °C for 1 - 2 h to obtain a lightweight and high-strength material.

[0022] By adopting the above technical solution, first, nano-sized white corundum powder is mixed with an epoxy adhesive solution, so that the nano-sized white corundum powder is evenly distributed in the epoxy adhesive; subsequently, when the corundum glue solution is sprayed on the surface of hollow glass microspheres, the nano-sized white corundum powder can be evenly adhered to the surface of the hollow glass microspheres. After air-drying at a temperature of 40 - 60 °C for 1 - 2 h, the corundum glue solution basically loses its fluidity, but its viscosity remains, which is convenient for the subsequent stirring of the lightweight and high-strength material in water. It can not only bond alumina fibers but also will not disperse in water.

[0023] Optionally, before the step Sa, the hollow glass microspheres are etched with 20 - 30% hydrochloric acid at a temperature of 25 - 45 °C for 10 - 30 min.

[0024] By adopting the above technical solution, the purpose of etching the hollow glass microspheres with hydrochloric acid of appropriate concentration is to increase the specific surface area of the hollow glass microspheres, so that the uneven hollow glass microspheres can adhere to the epoxy adhesive more firmly, which is beneficial to the subsequent experimental steps.

[0025] In summary, the present application has the following beneficial effects: 1. The corundum powder of the present application is adhered to the surface of the hollow glass microspheres through an epoxy resin adhesive, so that while the corundum powder exerts its high compressive strength performance, it is combined with the hollow glass microspheres to form a coating structure of hollow glass microspheres @ corundum powder; one end of the alumina fiber is adhered to the lightweight and high-strength material through the epoxy adhesive solution, and the remaining part is bonded to other components of the lightweight concrete, ensuring that the overall density of the lightweight concrete is relatively uniform, with high and uniform compressive strength, and it is difficult to generate cracks; 2. In the present application, the thermal expansion coefficients of the corundum powder and the alumina fiber are exactly between those of the hollow glass microspheres and the concrete. When the lightweight concrete encounters different hot and cold temperatures, the coating connection structure of hollow glass microspheres @ corundum powder - alumina fiber can prevent the lightweight concrete from generating cracks and extend the service life of the lightweight concrete; 3. In step S1 of the present application, the epoxy adhesive in the lightweight and high-strength material can tightly adhere to the surface of the hollow glass microspheres and can also bond the alumina fibers. Under appropriate temperature conditions, the epoxy adhesive gradually solidifies completely in water to obtain an aluminum fiber lightweight and high-strength material; in step S2, the aluminum fiber lightweight and high-strength material is added to the mixed traditional concrete slurry and mixed continuously to obtain a lightweight concrete for bridge deck paving with uniform distribution of aluminum fiber lightweight and high-strength materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1Designed to show the curve graphs of the 7-day compressive strength changes of the lightweight concretes prepared in Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 5 after being stored at environmental temperatures of -20°C, 0°C, 25°C, and 45°C respectively; Figure 2 Designed to show the curve graphs of the 28-day expansion rate changes of the lightweight concretes prepared in Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 5 after being stored at environmental temperatures of -20°C, 0°C, 25°C, and 45°C respectively. Specific implementation manners

[0027] The raw materials of the examples and comparative examples of this application are all commercially available.

[0028] Ethanol is of analytical purity; the portland cement is type P·Ⅱ portland cement with a strength grade of 52.5; the particle size of the quartz sand is 4 - 8mm; the silica fume is SF96 microsilica powder; the water reducer is H-928 polycarboxylate-based high-performance water reducer; The following further elaborates on this application in combination with examples and comparative examples. Example 1

[0029] A preparation method of a lightweight concrete for bridge deck paving includes the following steps: Preparation of lightweight high-strength materials: Pretreatment: Mix 13g of hollow glass microspheres with a model of HGS10000 and a particle size of 30 - 50μm with 500mL of 20% hydrochloric acid at a temperature of 45°C, and stir and etch at a speed of 100rpm for 10min to obtain etched hollow glass microspheres; Step Sa: Add 8g of nano-sized white corundum powder with a particle size of 1 - 5nm to 30g of an ethanol solution of epoxy adhesive, and the volume ratio of epoxy adhesive to ethanol is 1:10, stir at a speed of 150rpm for 10min to obtain corundum glue solution; Step Sb: Spray the corundum glue solution on the surface of the etched hollow glass microspheres, nozzle diameter: 1.2mm, spraying speed: 5g / s, atomizing pressure: 0.3MPa, the distance between the spray gun mouth and the surface of the etched hollow glass microspheres is within 200mm, environmental temperature: 25°C; after spraying, air dry at a temperature of 40 - 60°C for 1 - 2h to obtain lightweight high-strength materials.

[0030] Preparation of a lightweight concrete for bridge deck paving: Step S1: Mix the lightweight and high-strength material with 10 g of alumina fibers with a length of 20 - 50 mm in 500 mL of water at 40 °C, and mix and stir at a speed of 30 rpm at room temperature for 18 h to obtain an aqueous solution of aluminum fiber lightweight and high-strength material. Centrifuge the aqueous solution of aluminum fiber lightweight and high-strength material at a centrifugal speed of 200 rpm for 3 min to obtain the aluminum fiber lightweight and high-strength material; Step S2: Add 80 g of portland cement, 120 g of quartz sand, 10 g of silica fume, and 3 g of water reducer to 20 g of water, mix and stir at a speed of 20 rpm at room temperature for 30 min, then add the aluminum fiber lightweight and high-strength material, and continue to mix and stir at a speed of 20 rpm for 30 min to obtain a lightweight concrete for bridge deck paving. Example 2

[0031] A preparation method of a lightweight concrete for bridge deck paving, comprising the following steps: Preparation of lightweight and high-strength material: Pretreatment: Mix 26 g of hollow glass microspheres with a model of HGS10000 and a particle size of 30 - 50 μm with 500 mL of 30% hydrochloric acid at a temperature of 25 °C, and stir and etch at a speed of 100 rpm for 30 min to obtain etched hollow glass microspheres; Step Sa: Add 4 g of nano-sized white corundum powder with a particle size of 1 - 5 nm to 50 g of epoxy adhesive ethanol solution, the volume ratio of epoxy adhesive to ethanol is 1:10, stir at a speed of 100 rpm for 20 min to obtain corundum glue solution; Step Sb: Spray the corundum glue solution on the surface of the etched hollow glass microspheres, nozzle diameter: 1.2 mm, spraying speed: 5 g / s, atomization pressure: 0.3 MPa, the distance between the spray gun nozzle and the surface of the etched hollow glass microspheres is within 150 mm, ambient temperature: 25 °C; After spraying, air dry at a temperature of 60 °C for 1 h to obtain the lightweight and high-strength material.

[0032] Preparation of a lightweight concrete for bridge deck paving: Step S1: Mix the lightweight and high-strength material with 5 g of alumina fibers with a length of 20 - 50 mm in 500 mL of water at 60 °C, and mix and stir at a speed of 15 rpm at room temperature for 26 h to obtain an aqueous solution of aluminum fiber lightweight and high-strength material. Centrifuge the aqueous solution of aluminum fiber lightweight and high-strength material at a centrifugal speed of 200 rpm for 3 min to obtain the aluminum fiber lightweight and high-strength material; Step S2: Add 100 g of portland cement, 200 g of quartz sand, 20 g of silica fume, and 0.6 g of water reducing agent to 45 g of water, mix and stir at a speed of 10 rpm at room temperature for 60 min, then add the aluminum fiber lightweight high-strength material, and continue to mix and stir at a speed of 10 rpm for 60 min to obtain a lightweight concrete for bridge deck paving. Example 3

[0033] A preparation method of a lightweight concrete for bridge deck paving, comprising the following steps: Preparation of lightweight high-strength material: Pretreatment: Mix 20 g of hollow glass microspheres with a model of HGS10000 and a particle size of 30 - 50 μm with 500 mL of 30% hydrochloric acid at a temperature of 45°C, and stir and etch at a speed of 100 rpm for 30 min to obtain etched hollow glass microspheres; Step Sa: Add 6 g of nano-sized white corundum powder with a particle size of 1 - 5 nm to 40 g of epoxy adhesive ethanol solution, the volume ratio of epoxy adhesive to ethanol is 1:10, stir at a speed of 150 rpm for 20 min to obtain corundum glue solution; Step Sb: Spray the corundum glue solution on the surface of the etched hollow glass microspheres, nozzle diameter: 1.2 mm, spraying speed: 5 g / s, atomization pressure: 0.3 MPa, the distance between the spray gun and the surface of the etched hollow glass microspheres is within 200 mm, ambient temperature: 25°C; after spraying, air dry at a temperature of 60°C for 2 h to obtain a lightweight high-strength material.

[0034] Preparation of a lightweight concrete for bridge deck paving: Step S1: Mix the lightweight high-strength material with 7 g of alumina fibers with a length of 20 - 50 mm in 500 mL of water at 60°C, and mix and stir at a speed of 30 rpm at room temperature for 26 h to obtain an aluminum fiber lightweight high-strength material aqueous solution, and centrifuge the aluminum fiber lightweight high-strength material aqueous solution at a centrifugal speed of 200 rpm for 3 min to obtain an aluminum fiber lightweight high-strength material; Step S2: Add 90 g of portland cement, 160 g of quartz sand, 15 g of silica fume, and 2 g of water reducing agent to 30 g of water, mix and stir at a speed of 20 rpm at room temperature for 30 min, then add the aluminum fiber lightweight high-strength material, and continue to mix and stir at a speed of 20 rpm for 60 min to obtain a lightweight concrete for bridge deck paving. Example 4

[0035] The difference from Example 3 is that the model of the hollow glass microspheres in the lightweight high-strength material is replaced with HL15. Example 5

[0036] The difference from Example 3 is that the nano-sized white corundum powder with a particle size of 1-5 nm in step Sa is replaced with micron-sized white corundum powder with a particle size of 5-10 μm of equal weight. Example 6

[0037] The difference from Example 3 is that the alumina fiber in step S1 is replaced with an alumina fiber with a length of 20-50 μm. Example 7

[0038] The difference from Example 3 is that the ethanol solution of epoxy adhesive in step Sa is replaced with an ethyl acetate solution of epoxy adhesive of equal volume. Example 8

[0039] The difference from Example 3 is that air drying is not carried out in step Sb, and the specific steps are as follows: Step Sb: Spray the corundum glue solution on the surface of the etched hollow glass microspheres. Nozzle diameter: 1.2 mm, spraying speed: 5 g / s, atomization pressure: 0.3 MPa, the distance between the spray gun nozzle and the surface of the etched hollow glass microspheres is within 200 mm, ambient temperature: 25°C; after spraying, a lightweight and high-strength material is obtained. Example 8 The difference from Example 3 is that no pretreatment is carried out in the preparation of the lightweight and high-strength material.

[0040] Comparative Example 1 The difference from Example 3 is that the preparation step of the lightweight and high-strength material is not carried out, and the lightweight and high-strength material is directly replaced with 20 g of hollow glass microspheres of model HGS10000 with a particle size of 30-50 μm of equal weight.

[0041] Comparative Example 2 The difference from Example 3 is that the ethanol solution of epoxy adhesive in step Sa is replaced with a nano-aluminum ethanol solution with equal weight and equal volume ratio.

[0042] Comparative Example 3 The difference from Example 3 is that the alumina fiber in step S1 is replaced with an equal weight of polypropylene fiber.

[0043] Comparative Example 4 The difference from Example 3 is that steps S1 and S2 are carried out simultaneously, and the specific steps are as follows: Preparation of a lightweight concrete for bridge deck paving: Step S1: Add lightweight and high-strength materials, 7 g of alumina fibers with a length of 20 - 50 mm, 90 g of portland cement, 160 g of quartz sand, 15 g of silica fume, and 2 g of water reducer into 30 g of water, and mix and stir at a speed of 20 rpm at room temperature for 90 min to obtain a lightweight concrete for bridge deck paving.

[0044] Comparative Example 5 The difference from Example 3 is that hollow glass microspheres are not added, and the specific steps are as follows: Preparation of a lightweight concrete for bridge deck paving: Add 90 g of portland cement, 160 g of quartz sand, 15 g of silica fume, and 2 g of water reducer into 30 g of water, mix and stir at a speed of 20 rpm at room temperature for 30 min, then add aluminum fiber lightweight and high-strength materials, and continue to mix and stir at a speed of 20 rpm for 60 min to obtain a lightweight concrete for bridge deck paving.

[0045] Performance detection test Detection method

[0046] The performance of the lightweight concrete of this application was detected with reference to GB / T50010 - 2010 "Concrete Structure Design Standard". The 7-day compressive strength, density, elastic modulus, axial compressive strength, and slump of the lightweight concrete prepared in Example 1, Example 2, and Example 3 were detected, and the detection results are shown in Table 1; the 7-day compressive strength, density, and elastic modulus of the lightweight concrete prepared in other examples and comparative examples were detected, and the detection results are shown in Table 2; High and low temperature experiment: The lightweight concrete prepared in Example 3 and Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 5 were stored at environmental temperatures of -20°C, 0°C, 25°C, and 45°C respectively, and then the 7-day compressive strength and 28-day expansion rate were detected. The detection results are shown in the Figure 1 and the Figure 2 specification appendix.

[0047] Table 1

[0048] 7-day compressive strength / MPa <![CDATA[Density / (kg / m 3 )]]> Elastic modulus / GPa Axial compressive strength / MPa Slump / mm Example 1 67 1915 31.4 40.2 244 Example 2 65 1910 31.6 40.1 246 Example 3 69 1905 32.5 41.3 250 Combining the data of Examples 1, 2, and 3, it can be seen that the 7-day compressive strength, density, elastic modulus, axial compressive strength, and slump of the lightweight concrete prepared in Examples 1, 2, and 3 all meet the requirements for the concrete of the paved bridge deck; and the only difference among Examples 1, 2, and 3 lies in the different raw material composition ratios, which proves that within the range of the raw material compositions of Examples 1, 2, and 3, lightweight concrete with good quality can be prepared; among them, the 7-day compressive strength, elastic modulus, axial compressive strength, and slump of Example 3 are the highest, and the density is the lowest. Therefore, the raw material composition of Example 3 is the best ratio for preparing lightweight concrete.

[0049] Table 2 7-day compressive strength / MPa <![CDATA[Density / (kg / m 3 )]]> Elastic modulus / GPa Example 1 67 1915 34.4 Example 2 65 1910 34.6 Example 3 69 1905 35.5 Example 4 60 1911 32.4 Example 5 62 2113 30.6 Example 6 61 2050 29.4 Example 7 63 1954 30.3 Example 8 64 1948 29.9 Example 9 61 2251 30.3 Comparative Example 1 54 1895 28.5 Comparative Example 2 56 1965 27.3 Comparative Example 3 53 1912 27.7 Comparative Example 4 51 2000 27.1 Comparative Example 5 51 2500 27.2 The difference between Example 4 and Example 3 is that the type of hollow glass microspheres used in the lightweight concrete prepared in Example 4 is different. The results show that the 7-day compressive strength of the lightweight concrete prepared in Example 4 decreases, the density increases, and the elastic modulus decreases, which proves that after the type of hollow glass microspheres is replaced with HL15, the performance of the prepared lightweight concrete becomes worse. It is still the best choice to use the hollow glass microspheres of model HGS10000 in this application.

[0050] The difference between Example 5 and Example 3 is that the particle size of the white corundum powder used in Example 5 is micron-sized. Compared with the nano-sized white corundum powder, the micron-sized white corundum powder is difficult to tightly wrap the hollow glass microspheres, and may also disperse in water when encountering water later; the data results show that the 7-day compressive strength of the lightweight concrete prepared in Example 5 decreases, the density increases, and the elastic modulus decreases, which proves that the nano-sized white corundum powder is the best choice for this application.

[0051] The difference between Example 6 and Example 3 is that the alumina fiber used in Example 6 is micron-sized. Compared with the millimeter-sized alumina fiber, the micron-sized alumina fiber is difficult to connect other components in the concrete while connecting the lightweight and high-strength materials; the data results show that the 7-day compressive strength of the lightweight concrete prepared in Example 6 decreases, the density increases, and the elastic modulus decreases, which proves that the millimeter-sized alumina fiber is the best choice for this application.

[0052] The difference between Example 7 and Example 3 is that the epoxy adhesive solvent used in Example 7 is ethyl acetate. Compared with ethanol, ethyl acetate is more difficult to volatilize, resulting in the dispersion of nano-sized white corundum powder in water in the subsequent steps; the data results show that the 7-day compressive strength of the lightweight concrete prepared in Example 7 decreases, the density increases, and the elastic modulus decreases, which proves that the solvent of the epoxy adhesive solvent being ethanol is the best choice for this application.

[0053] Example 8 is different from Example 3 in that the corundum glue mucus used in Example 8 is not air-dried. The data results show that the 7-day compressive strength of the lightweight concrete prepared in Example 8 decreases, the density increases, and the elastic modulus decreases, proving that the air-drying step of the corundum glue mucus must be carried out.

[0054] Example 9 is different from Example 3 in that the hollow glass microspheres in Example 9 are not etched, so the specific surface area of the hollow glass microspheres in Example 9 is smaller than that of the hollow glass microspheres in Example 3; the data results show that the 7-day compressive strength of the lightweight concrete prepared in Example 9 decreases, the density increases, and the elastic modulus decreases, proving that etching the surface of the hollow glass microspheres and increasing the specific surface area of the hollow glass microspheres can promote more and stronger adhesion of the corundum glue mucus on the surface of the hollow glass microspheres.

[0055] Comparative Example 1 is different from Example 3 in that no nano-sized white fused alumina powder is added in Comparative Example 1, so there is no nano-sized white fused alumina powder on the surface of the hollow glass microspheres in the lightweight concrete prepared in Comparative Example 1, and the compressive strength of the lightweight concrete cannot be improved; the data results show that although the density of the lightweight concrete prepared in Comparative Example 1 decreases, the 7-day compressive strength and elastic modulus also decrease, proving that nano-sized white fused alumina powder is essential in the lightweight concrete of the present application.

[0056] Comparative Example 2 is different from Example 3 in that the epoxy adhesive ethanol solution in Comparative Example 2 is replaced with a nano-aluminum ethanol solution, and the nano-aluminum ethanol solution cannot solidify in water, so the nano-sized white fused alumina powder cannot adhere firmly to the surface of the hollow glass microspheres; the data results show that although the density of the lightweight concrete prepared in Comparative Example 2 is lower than 2000 kg / m 3 , but the 7-day compressive strength and elastic modulus also decrease, proving that it is necessary to use an epoxy adhesive ethanol solution that can firmly adhere the nano-sized white fused alumina powder to the surface of the hollow glass microspheres and can solidify in water.

[0057] Comparative Example 3 is different from Example 3 in that the alumina fiber in Comparative Example 3 is replaced with a polypropylene fiber. Since the thermal expansion coefficient of the polypropylene fiber is quite different from that of other substances, it will affect the physical properties of the lightweight concrete; the data results show that although the density of the lightweight concrete prepared in Comparative Example 3 is lower than 2000 kg / m 3 , but the 7-day compressive strength and elastic modulus also decrease, proving that it is necessary to use an alumina fiber with high self-compressive strength and a thermal expansion coefficient close to that of other materials.

[0058] The difference between Comparative Example 4 and Example 3 is that in Comparative Example 4, Step 1 and Step 2 are carried out simultaneously. As a result, the alumina fibers cannot be connected to the surface of the lightweight high-strength material but are mixed in all substances. The data results show that the 7-day compressive strength of the lightweight concrete prepared in Comparative Example 4 decreases, the density increases, and the elastic modulus decreases. This proves that the alumina fibers must be connected to the surface of the lightweight high-strength material through Step 1, and Step 1 and Step 2 cannot be carried out simultaneously.

[0059] The difference between Comparative Example 5 and Example 3 is that the lightweight concrete prepared in Comparative Example 5 does not contain hollow glass microspheres. Thus, the lightweight concrete in Comparative Example 5 is equivalent to traditional concrete. The data results show that the 7-day compressive strength of the lightweight concrete prepared in Comparative Example 5 decreases, the density increases, and the elastic modulus decreases. This proves that the hollow glass microspheres of the present application are very important, and the lightweight high-strength material is also very important, which play a decisive role in the properties of the lightweight concrete.

[0060] From the Figure 1 and the Figure 2 It can be seen that compared with the lightweight concrete of Example 3, the lightweight concretes of other comparative examples not only have a significant decrease in 7-day compressive strength compared to 25 °C at different environmental temperatures, but also have a greater change in expansion rate. The greater the expansion change rate, the greater the change in the internal structure of the lightweight concrete, and the more obvious the decline in various properties of the lightweight concrete. This shows that the lightweight concrete prepared in Example 3 of the present application is more adaptable to different external temperature environments compared to the lightweight concretes of different comparative examples.

[0061] This specific embodiment is only an explanation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A lightweight concrete for bridge deck paving, characterized in that: The invention comprises the following raw materials in parts by weight: 20 to 40 parts of lightweight high-strength materials, 5 to 10 parts of alumina fibers, 80 to 100 parts of silicate cement, 120 to 200 parts of quartz sand, 10 to 20 parts of silica fume, 0.6 to 3 parts of water reducer, and 20 to 45 parts of water; based on the weight of the lightweight high-strength materials, the lightweight high-strength materials include 13 to 26 parts of hollow glass microspheres, 4 to 8 parts of corundum powder, and 30 to 50 parts of epoxy adhesive solution.

2. The lightweight concrete for bridge deck paving according to claim 1 is characterized in that: The hollow glass microspheres are HGS series hollow glass microspheres.

3. The lightweight concrete for bridge deck paving according to claim 1, characterized in that: The particle size of the hollow glass microspheres is 30-50 μm.

4. The lightweight concrete for bridge deck paving according to claim 1, characterized in that: The corundum powder is nano-grade white corundum powder.

5. The lightweight concrete for bridge deck paving according to claim 1, characterized in that: The length of the alumina fiber is 20-50 mm.

6. The lightweight concrete for bridge deck paving according to claim 1, characterized in that: The epoxy adhesive solution is an epoxy adhesive ethanol solution.

7. A method for preparing lightweight concrete for bridge deck paving according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, mixing the light high-strength material and the alumina fiber in water at 40-60° C. at a speed of 15-30 rpm for 18-26 hours, and removing water by centrifugation to obtain the aluminum fiber light high-strength material; Step S2, adding silicate cement, quartz sand, silica fume and water reducing agent into water, mixing and stirring at a speed of 10-20 rpm for 10-30 minutes at room temperature, then adding aluminum fiber lightweight high-strength material, and continuing to mix and stir at a speed of 10-20 rpm for 30-60 minutes to obtain a lightweight concrete for bridge deck paving.

8. The method for preparing lightweight concrete for bridge deck paving according to claim 7, characterized in that: The method for preparing the lightweight high-strength material comprises the following steps: Step Sa: adding nano-sized white corundum powder to the epoxy adhesive, stirring at a speed of 100-150 rpm for 10-20 min to obtain a corundum adhesive solution; Step Sb: Spraying the corundum adhesive onto the surface of the hollow glass microspheres, and then air-drying them at a temperature of 40-60° C. for 1-2 hours to obtain a light and high-strength material.

9. The method for preparing lightweight concrete for bridge deck paving according to claim 7, characterized in that: Before the step Sa, the hollow glass microspheres are etched with 20-30% hydrochloric acid at a temperature of 25-45° C. for 10-30 minutes.

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