Bridge anti-disturbance concrete material and preparation method thereof

Abstract

The invention provides a bridge anti-disturbance concrete material and a preparation method thereof, and belongs to the technical field of building materials, the bridge anti-disturbance concrete material comprises a gel material, a reinforcing material and a functional additive; the reinforcing material comprises fibers, modified styrene butadiene rubber particles and self-repairing capsules; the self-repairing capsule comprises a water phase and an oil phase, the water phase contains nano calcium oxide, and the oil phase contains an HDI-ethylenediamine copolymer. The invention provides a bridge anti-disturbance concrete material and a preparation method thereof. The adaptability of concrete to high-frequency vibration and extremely low-temperature environments is improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a bridge anti-disturbance concrete material and its preparation method. Background Technology

[0002] In bridge engineering, key components such as ramp concrete, spliced ​​concrete, and anchorage concrete of suspension bridges are prone to quality defects under long-term vibration loads, affecting the structural durability and safety.

[0003] Firstly, vibration causes the surface mortar of the concrete to detach, exposing the aggregate. Under repeated loading, micro-cracks inside the concrete connect to form macro-cracks. Long-term vibration can also promote the development of initial defects (such as air bubbles and water channels) into through cracks. Cracks accelerate the penetration of moisture and chloride ions, easily causing steel corrosion and thus leading to durability deterioration. At the same time, once cracks become channels for moisture penetration, damage will be exacerbated under winter frost heave conditions, reducing overall strength. Secondly, the stress in the anchorage zone of suspension bridges is complex. The main cable transmits high-frequency vibrations (typically 5-30Hz) under wind vibration and vehicle loads, causing the accumulation of micro-cracks inside the concrete, leading to fatigue damage inside the concrete, a decrease in strength and dynamic elastic modulus, and making the concrete in the anchorage zone prone to crushing or spalling.

[0004] Current technologies often add crack-resistant materials (such as steel fibers), which are costly and prone to corrosion. Chinese patent CN106587787B, entitled "Anti-disturbance Concrete and its Preparation Method," discloses an anti-disturbance concrete comprising grout, aggregate, water, and additives, with a mass ratio of grout:aggregate:water = 69.7:20.9:9.4. The additives are one or two of fibers, crack-resistant toughening admixtures, and early-strength agents. The fiber content is 0.1%–0.4% of the grout, the crack-resistant toughening admixture is 0.01%–0.03% of the grout, and the early-strength agent is 0.5%–1% of the grout. While the above technical solution uses fibers and crack-resistant toughening admixtures to improve toughness, it still suffers from fiber agglomeration and poor dispersibility, and lacks adaptability to high-frequency vibration and extreme low-temperature environments. Summary of the Invention

[0005] In view of this, the present invention provides a bridge anti-disturbance concrete material and its preparation method, which improves the adaptability of concrete to high-frequency vibration and extreme low-temperature environment.

[0006] To achieve the above objectives, the present invention provides a bridge anti-disturbance concrete material, comprising a gel material, a reinforcing material, and functional additives; the reinforcing material comprises fibers, modified styrene-butadiene rubber particles, and self-healing capsules; the self-healing capsules comprise an aqueous phase and an oil phase, wherein the aqueous phase contains nano-calcium oxide, and the oil phase contains HDI-ethylenediamine copolymer.

[0007] Optionally, the preparation of the self-healing capsule includes the following steps: S1. Disperse nano-CaO in ethanol, add silane coupling agent, stir evenly, and then centrifuge and dry; disperse the centrifuged and dried nano-CaO in silicone oil, and sonicate to obtain an oil phase; S2. Dissolve the HDI-ethylenediamine copolymer in acetone and phosphate buffer solution, maintaining a neutral environment, to obtain the aqueous phase; S3. Slowly add the oil phase to the aqueous phase and emulsify by high-speed shearing to form a W / O emulsion. Pour the W / O emulsion into an aqueous solution containing polyvinyl alcohol and emulsify it again to form a W / O / W complex emulsion. Heat and stir the W / O / W complex emulsion to crosslink and solidify it to form a microcapsule shell.

[0008] Optionally, in S1, the weight of the silane coupling agent is 1-2% of the weight of the nano-CaO; the stirring conditions are a temperature of 55-65℃ for 1.5-2.5 h and an ultrasonic treatment time of 20-40 min; in S2, the concentration of the HDI-ethylenediamine copolymer dissolved in acetone is 10-15%, and the phosphate buffer solution has a concentration of 0.1 mol / L and a pH of 7.4; in S3, the volume ratio of the oil phase to the water phase is 1:3; the shear emulsification conditions are a rotation speed of 9000-11000 rpm for 4-6 min; the secondary emulsification conditions are a rotation speed of 4000-5000 rpm for 2-4 min; and the heating and stirring conditions are a temperature of 45-55℃ for 5.5-6.5 h.

[0009] Optionally, the preparation method of the modified styrene-butadiene rubber particles includes the following steps: dispersing styrene-butadiene rubber particles in toluene solvent, adding silane coupling agent, reacting at 60-80℃ for 2-4 hours, and obtaining modified styrene-butadiene rubber particles after washing and drying.

[0010] Optionally, the fiber is copper-plated steel fiber or polyester fiber.

[0011] Optionally, the copper layer thickness of the copper-plated steel fiber is 3~5μm, and the resistivity is ≤1.5×10⁻⁶. -7 Ω·m, with a length-to-diameter ratio of 60-80.

[0012] Optionally, the modified styrene-butadiene rubber particles have a particle size of 50-100 μm.

[0013] Optionally, the gel material includes silicate cement, nano-kaolin, graphene-modified silica aerogel, and ultrafine slag powder.

[0014] Optionally, the graphene-modified silica aerogel is produced by Zhejiang Shaoxing Shengnuo New Material Co., Ltd., and the product model is SN-G-SiO2.

[0015] Optionally, the specific surface area of ​​the ultrafine slag powder is ≥800m² / kg.

[0016] Optionally, the functional additives are water-reducing agents, air-entraining agents, and potassium titanate whiskers.

[0017] Optionally, the water-reducing agent is a triethanolamine derivative; the air-entraining agent is calcium stearate.

[0018] Optional components include the following by weight: 40-50 parts silicate cement, 8-15 parts nano-kaolin, 3-5 parts graphene-modified silica aerogel, 10-25 parts ultrafine slag powder, 1.5-2 parts copper-plated steel fiber, 0.5-1.0 parts polyester fiber, 5-8 parts modified styrene-butadiene rubber granules, 2-4 parts self-healing microcapsules, 0.5-1 part water-reducing agent, 0.01-0.03 parts air-entraining agent, 1-2 parts potassium titanate whiskers, and 8-11 parts water.

[0019] To achieve the above objectives, the present invention also provides a method for preparing bridge anti-disturbance concrete material, comprising the following steps: S1. Mix silicate cement, nano-kaolin, graphene-modified silica aerogel, ultrafine slag powder, and modified styrene-butadiene rubber particles evenly, then add copper-plated steel fibers and dry mix evenly. S2. Add water-reducing agent, self-healing microcapsules and water to the material mixed in step S1 and mix evenly. Then add polyester fiber and mix evenly. S3. Add air-entraining agent and potassium titanate whiskers to the material mixed in step S2, and stir to obtain bridge anti-disturbance concrete material.

[0020] Optionally, the time for adding copper-plated steel fibers and mixing them evenly is 50-70 seconds, the time for adding polyester fibers and mixing them evenly is 85-95 seconds, and the stirring temperature of S3 is 10-15℃.

[0021] The above-described technical solution of the present invention has at least the following beneficial effects: The reinforcing material provided by this invention features copper-plated steel fibers with low resistance and strong conductivity, which inhibit rusting. The addition of polyester fibers suppresses early plastic cracking. Self-healing microcapsules trigger rupture at the crack, releasing nano-calcium oxide particles that expand upon contact with water, aiding in crack closure. The resulting alkaline environment causes the gel material to form a gel structure that fills the crack. Furthermore, this invention uses modified styrene-butadiene rubber particles to dissipate vibrational energy. The combination of these three elements—early-stage fiber inhibition of cracking, continuous vibrational energy dissipation to prevent cracking, and self-repair even if cracking occurs later—achieves the concrete's adaptability to high-frequency vibration.

[0022] In this invention, the air-entraining agent combined with ultrafine slag powder improves the frost resistance, impermeability, and crack resistance of concrete by introducing microbubbles, while also optimizing fluidity. The introduction of slag powder also lowers the hydration reaction temperature of the material, reducing the generation of temperature cracks and shrinkage cracks caused by temperature accumulation and internal and external temperature differences during construction.

[0023] The concrete material obtained by the technical solution provided by this invention has been tested and found that the strength decay rate under dynamic load is controlled within 5%; the self-repair cycle of microcracks is ≤14 days (60% humidity environment); and the mass loss rate after 300 freeze-thaw cycles is ≤1.5%. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0025] Example 1 The manufacturer of graphene-modified silica aerogel is Zhejiang Shaoxing Shengnuo New Material Co., Ltd., and the product model is SN-G-SiO2 series.

[0026] The preparation method of modified styrene-butadiene rubber granules includes the following steps: Step 1: Disperse styrene-butadiene rubber particles in toluene solvent; Step 2: Add silane coupling agent KH-550 and react at 70°C for 3 hours; Step 3: After washing and drying, styrene-butadiene rubber (SBR) modified granules are obtained. The SBR granules are manufactured by Lanzhou Petrochemical Company of China National Petroleum Corporation (CNPC).

[0027] The preparation method of self-healing microcapsules includes the following steps: 1. Disperse nano-CaO in ethanol, add 1-2% silane coupling agent KH-550, stir at 60℃ for 2h, centrifuge and dry, disperse the treated CaO in silicone oil, and sonicate for 30min until uniform to obtain oil phase.

[0028] 2. Dissolve the HDI-ethylenediamine copolymer in acetone to a concentration of 10-15%, add 0.1M pH 7.4 phosphate buffer solution, and maintain a neutral environment to obtain the aqueous phase.

[0029] 3. Slowly add the oil phase (containing CaO) to the aqueous phase (containing polyurea prepolymer) at an oil-to-water ratio of 1:3, and emulsify at high speed (10,000 rpm, 5 min) to form a W / O emulsion; pour the W / O emulsion into an aqueous solution containing 1% polyvinyl alcohol (PVA), and emulsify a second time (5,000 rpm, 3 min) to form a W / O / W complex emulsion; heat to 50℃ and stir for 6 h to allow the interfacial polyurea to crosslink and solidify to form a microcapsule shell.

[0030] This invention provides a method for preparing bridge anti-disturbance concrete material, comprising the following steps: taking 50 parts of silicate cement, 11 parts of nano-kaolin, 5 parts of graphene-modified silica aerogel, 20 parts of ultrafine slag powder, 2 parts of copper-plated steel fiber, 1.0 part of polyester fiber, 6 parts of modified styrene-butadiene rubber particles, 3 parts of self-healing microcapsules, 0.58 parts of water-reducing agent, 0.02 parts of air-entraining agent, 1.4 parts of potassium titanate whiskers, and 10.3 parts of water. The silicate cement is 42.5 silicate cement, the specific surface area of ​​the ultrafine slag powder is 800 m² / kg, the copper layer thickness of the copper-plated steel fiber is 5 μm, and the resistivity is ≤1.5 × 10⁻⁶. -7 The modified styrene-butadiene rubber has an Ω·m, an aspect ratio of 70, a particle size of 80 μm, a water-reducing agent of triethanolamine derivative, and an air-entraining agent of calcium stearate.

[0031] The silicate cement, nano-kaolin, graphene-modified silica aerogel, ultrafine slag powder, and modified styrene-butadiene rubber particles are mixed evenly (mixing time is 30s, stirring speed is 35rpm), and then copper-plated steel fibers are added and dry-mixed for 60s (stirring speed is 35rpm) to obtain a preliminary mixed material. Triethanolamine derivative, self-healing microcapsules and water were added to the initial mixed material and mixed evenly (mixing time 30s, stirring speed 35rpm). Polyester fiber was added and mixed for 90s (stirring speed 40rpm) to obtain the intermediate mixed material. Calcium stearate and potassium titanate whiskers were added to the intermediate mixture and stirred at 12°C to obtain bridge anti-disturbance concrete material (stirring time was 30s and speed was 40rpm).

[0032] Example 2 This invention provides a method for preparing bridge anti-disturbance concrete material, comprising the following steps: taking 40 parts of silicate cement, 15 parts of nano-kaolin, 3 parts of graphene-modified silica aerogel, 25 parts of ultrafine slag powder, 1.5 parts of copper-plated steel fiber, 0.5 parts of polyester fiber, 5 parts of modified styrene-butadiene rubber particles, 4 parts of self-healing microcapsules, 0.5 parts of water-reducing agent, 0.01 parts of air-entraining agent, 1 part of potassium titanate whiskers, and 9.5 parts of water. The silicate cement is 42.5 silicate cement, the specific surface area of ​​the ultrafine slag powder is 800 m² / kg, the copper layer thickness of the copper-plated steel fiber is 4 μm, and the resistivity is ≤1.5 × 10⁻⁶. -7 The modified styrene-butadiene rubber has an Ω·m, an aspect ratio of 60, a particle size of 100μm, a water-reducing agent of triethanolamine derivative, and an air-entraining agent of calcium stearate.

[0033] The silicate cement, nano-kaolin, graphene-modified silica aerogel, ultrafine slag powder, and modified styrene-butadiene rubber particles are mixed evenly (mixing time is 30s, stirring speed is 35rpm), and then copper-plated steel fibers are added and dry-mixed for 50s (stirring speed is 35rpm) to obtain a preliminary mixed material. Triethanolamine derivative, self-healing microcapsules and water were added to the initial mixed material and mixed evenly (mixing time 30s, stirring speed 35rpm). Polyester fiber was added and mixed for 95s (stirring speed 40rpm) to obtain the intermediate mixed material. Calcium stearate and potassium titanate whiskers were added to the intermediate mixture and stirred at 15°C to obtain bridge anti-disturbance concrete material (stirring time: 30s, speed: 40rpm).

[0034] Example 3 This invention provides a method for preparing bridge anti-disturbance concrete material, comprising the following steps: taking 45 parts of silicate cement, 8 parts of nano-kaolin, 4 parts of graphene-modified silica aerogel, 10 parts of ultrafine slag powder, 1.8 parts of copper-plated steel fiber, 0.7 parts of polyester fiber, 8 parts of modified styrene-butadiene rubber particles, 2 parts of self-healing microcapsules, 1 part of water-reducing agent, 0.03 parts of air-entraining agent, 2 parts of potassium titanate whiskers, and 8.5 parts of water. The silicate cement is 42.5 silicate cement, the specific surface area of ​​the ultrafine slag powder is 800 m² / kg, the copper layer thickness of the copper-plated steel fiber is 3 μm, and the resistivity is ≤1.5 × 10⁻⁶. -7 The modified styrene-butadiene rubber has an Ω·m, an aspect ratio of 80, a particle size of 50 μm, a water-reducing agent of triethanolamine derivative, and an air-entraining agent of calcium stearate.

[0035] The silicate cement, nano-kaolin, graphene-modified silica aerogel, ultrafine slag powder, and modified styrene-butadiene rubber particles are mixed evenly (mixing time is 30s, stirring speed is 35rpm), and then copper-plated steel fibers are added and dry-mixed for 70s (stirring speed is 35rpm) to obtain a preliminary mixed material. Triethanolamine derivative, self-healing microcapsules and water were added to the initial mixed material and mixed evenly (mixing time 30s, stirring speed 35rpm). Polyester fiber was added and mixed for 85s (stirring speed 40rpm) to obtain the intermediate mixed material. Calcium stearate and potassium titanate whiskers were added to the intermediate mixture and stirred at 10°C to obtain bridge anti-disturbance concrete material (stirring time: 30s, speed: 40rpm).

[0036] Comparative Example Ordinary C50 concrete.

[0037] Performance testing: The concrete materials prepared in Examples 1-3 and the comparative example were poured into 40mm×40mm×160mm molds, vibrated to compact, and cured under standard conditions (20±2℃, RH≥95%) for 28 days. Their compressive strength, dynamic modulus of elasticity, maximum crack width, and chloride ion diffusion coefficient were tested. The performance test results are shown in Table 1. Test standard: The constant amplitude cyclic compressive stress method is based on the "Specification for Durability Design of Concrete Structures in Highway Engineering" (JTG / T 3310-2019).

[0038] Loading conditions: Stress level: 0.6×f e (f) e (28-day compressive strength) Loading frequency: 10Hz (simulating typical vibration frequency of a vehicle) Number of iterations: 2 × 10 6 This is equivalent to 20 years of heavy-load traffic. Table 1. Performance test results of concrete materials prepared in Examples 1-3 and comparative examples.

[0039] As shown in Table 1, the concrete materials prepared in Examples 1-3 of this application have a lower rate of decline in compressive strength and dynamic elastic modulus than the comparative example. Furthermore, the concrete materials prepared in Examples 1-3 have a lower chloride ion diffusion coefficient and a lower maximum crack width than the comparative example. This indicates that the concrete prepared in this application has enhanced adaptability to high-frequency vibration.

[0040] The concrete materials prepared in Examples 1-3 and the concrete materials prepared in the comparative example were subjected to freeze-thaw cycle tests. The test conditions were 300 cycles at -20℃ to 20℃. The results are shown in Table 2.

[0041] Table 2. Freeze-thaw cycle test results of concrete materials prepared in Examples 1-3 and comparative examples.

[0042] As shown in Table 2, the concrete material prepared in this application has stronger adaptability to low-temperature conditions compared to the comparative example.

[0043] The concrete materials prepared in Examples 1-3 were subjected to compressive cracking tests and their strength was recorded. More than 90% of the cracks were ≤0.3mm in width. The test blocks were cured in an environment with 60% humidity for 3d, 7d and 14d and their strength was tested. The results are shown in Table 3.

[0044] Table 3. Results of the compressive cracking test on the concrete materials prepared in Examples 1-3

[0045] As shown in Table 3, the microcracks in the concrete material prepared by this invention can be repaired by 80% or more within 14 days.

[0046] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bridge anti-disturbance concrete material, characterized in that, It includes gel materials, reinforcing materials, and functional additives; the reinforcing materials include fibers, modified styrene-butadiene rubber particles, and self-healing capsules; the self-healing capsules include an aqueous phase and an oil phase, the aqueous phase containing nano-calcium oxide, and the oil phase containing HDI-ethylenediamine copolymer.

2. The bridge anti-disturbance concrete material according to claim 1, characterized in that, The preparation of the self-healing capsule includes the following steps: S1. Disperse nano-CaO in ethanol, add silane coupling agent, stir evenly, and then centrifuge and dry; disperse the centrifuged and dried nano-CaO in silicone oil, and sonicate to obtain an oil phase; S2. Dissolve the HDI-ethylenediamine copolymer in acetone and phosphate buffer solution, maintaining a neutral environment, to obtain the aqueous phase; S3. Slowly add the oil phase to the aqueous phase and emulsify by high-speed shearing to form a W / O emulsion. Pour the W / O emulsion into an aqueous solution containing polyvinyl alcohol and emulsify it again to form a W / O / W complex emulsion. Heat and stir the W / O / W complex emulsion to crosslink and solidify it to form a microcapsule shell.

3. The bridge anti-disturbance concrete material according to claim 2, characterized in that, In S1, the weight of the silane coupling agent is 1-2% of the weight of the nano-CaO; the stirring conditions are a temperature of 55-65℃ for 1.5-2.5 h and an ultrasonic treatment time of 20-40 min. In S2, the concentration of the HDI-ethylenediamine copolymer dissolved in acetone is 10-15%, and the phosphate buffer solution has a concentration of 0.1 mol / L and a pH of 7.

4. In S3, the volume ratio of the oil phase to the water phase is 1:3; the shear emulsification conditions are a rotation speed of 9000-11000 rpm for 4-6 min; the secondary emulsification conditions are a rotation speed of 4000-5000 rpm for 2-4 min; and the heating and stirring conditions are a temperature of 45-55℃ for 5.5-6.5 h.

4. The bridge anti-disturbance concrete material according to claim 1, characterized in that, The method for preparing the modified styrene-butadiene rubber particles includes the following steps: dispersing styrene-butadiene rubber particles in toluene solvent, adding silane coupling agent, reacting at 60-80℃ for 2-4 hours, and then washing and drying to obtain modified styrene-butadiene rubber particles.

5. The bridge anti-disturbance concrete material according to claim 1, characterized in that, The fibers are copper-plated steel fibers and polyester fibers; the gel material includes silicate cement, nano-kaolin, graphene-modified silica aerogel, and ultrafine slag powder; the specific surface area of ​​the ultrafine slag powder is ≥800 m². ² / kg; the functional additives are water-reducing agents, air-entraining agents and potassium titanate whiskers.

6. The bridge anti-disturbance concrete material according to claim 5, characterized in that, The water-reducing agent is one of triethanolamine and triethanolamine derivatives; the air-entraining agent is calcium stearate.

7. The bridge anti-disturbance concrete material according to claim 1, characterized in that, The product comprises the following components in parts by weight: 40-50 parts silicate cement, 8-15 parts nano-kaolin, 3-5 parts graphene-modified silica aerogel, 10-25 parts ultrafine slag powder, 1.5-2 parts copper-plated steel fiber, 0.5-1.0 parts polyester fiber, 5-8 parts modified styrene-butadiene rubber granules, 2-4 parts self-healing microcapsules, 0.5-1 part water-reducing agent, 0.01-0.03 parts air-entraining agent, 1-2 parts potassium titanate whiskers, and 8-11 parts water.

8. A method for preparing bridge anti-disturbance concrete material as described in claim 7, characterized in that, Includes the following steps: S1. Mix silicate cement, nano-kaolin, graphene-modified silica aerogel, ultrafine slag powder, and modified styrene-butadiene rubber particles evenly, then add copper-plated steel fibers and dry mix evenly. S2. Add water-reducing agent, self-healing microcapsules and water to the material mixed in step S1 and mix evenly. Then add polyester fiber and mix evenly. S3. Add air-entraining agent and potassium titanate whiskers to the material mixed in step S2, and stir to obtain bridge anti-disturbance concrete material.

9. The method for preparing bridge anti-disturbance concrete material according to claim 8, characterized in that, The time for adding copper-plated steel fibers and mixing them evenly is 50-70 seconds, the time for adding polyester fibers and mixing them evenly is 85-95 seconds, and the stirring temperature of S3 is 10-15℃.

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