High-strength high-frost-resistance ultra-high fly ash content cement-based material
By constructing a three-dimensional nano-reinforced skeleton and biomimetic network using TX modifier, the problem of frost resistance and strength of ultra-high fly ash cement-based materials in frigid regions was solved, achieving improved high strength and high frost resistance, making it suitable for engineering applications in frigid regions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HOHAI UNIV
- Filing Date
- 2026-03-11
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, the frost resistance of ultra-high fly ash cement-based materials in frigid and cold regions is difficult to meet the actual engineering requirements. At the same time, the concrete strength is significantly reduced due to insufficient hydration reaction and deterioration of pore structure, which limits the resource utilization of fly ash.
Using TX modifiers, including aminocellulose nanofibers, bamboo extract, polydimethylsiloxane triol, mussel adhesive protein, and tyrosinase, a three-dimensional nano-reinforced skeleton is constructed to form a biomimetic network that forms multiple chemical bonds with the surface of fly ash and hydration products. Combined with a hydrophobic protective layer, this improves the mechanical properties and freeze-thaw resistance of the material.
It significantly improves the strength and frost resistance of ultra-high fly ash cementitious materials, can meet the engineering needs of cold regions, reduce raw material costs, solve the problem of fly ash accumulation, and has good reliability and engineering applicability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials, and more particularly to a high-strength, high-freeze-resistant, ultra-high fly ash cement-based material. Background Technology
[0002] Low-carbon concrete, as a promising and recyclable green material, has become an important carrier and support for the construction industry to move towards low-carbon transformation and achieve emission reduction targets. Meanwhile, with social development, global energy consumption continues to rise, and the output of fly ash, an industrial byproduct of coal combustion in thermal power plants, is increasing year by year. In areas with a high concentration of thermal power plants, fly ash production is enormous. The accumulation of large amounts of waste fly ash not only occupies land resources but also pollutes the natural environment. Currently, fly ash is used as an admixture in concrete, but general standards require its content not to exceed 40%. With the continuous increase in fly ash content, problems such as insufficient hydration reaction and deterioration of pore structure will lead to a significant decrease in concrete strength. At the same time, in severely cold and frigid regions such as Inner Mongolia, the frost resistance of cementitious materials with ultra-high fly ash content is difficult to meet the needs of actual engineering projects. Therefore, improving the resource utilization level of fly ash while simultaneously considering the actual engineering requirements for concrete strength and frost resistance has become a critical issue that urgently needs to be addressed. Summary of the Invention
[0003] Purpose of the invention: The purpose of this invention is to provide a high-strength, high-freeze-resistant ultra-high fly ash cement-based material that effectively improves the strength and freeze-thaw resistance of ultra-high fly ash cement-based materials.
[0004] To achieve the above objectives, the technical solution provided by the present invention is as follows:
[0005] This invention provides a high-strength, high-freeze-resistant, ultra-high-content fly ash cement-based material, comprising the following components by weight: 67-100 parts cement, 233-266 parts fly ash, 14-34 parts TX modifier, 140-400 parts fine aggregate, 0-270 parts coarse aggregate, and 57-70 parts water; the TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15-25 parts bamboo extract, 10-20 parts polydimethylsiloxane triol, 10-15 parts mussel adhesive protein, and 1.0-1.5 parts tyrosinase.
[0006] Preferably, the cement is P·I 42.5 silicate cement; the fly ash is Grade I fly ash that meets the national standard requirements.
[0007] Preferably, the fine aggregate is river sand that has passed through a 4.75 mm square sieve; the coarse aggregate is crushed stone with a continuous gradation of 5-20 mm particle size.
[0008] Preferably, the water is tap water.
[0009] Preferably, the aminocellulose nanofibers have a solid content of 2% and an amino content of not less than 0.8 mmol / g;
[0010] Preferably, the hydroxyl value of the polydimethylsiloxane triol is not less than 3%.
[0011] Preferably, the tyrosinase activity is not less than 1000 U / mg.
[0012] Preferably, the mussel agaric protein has a protein content of not less than 75%.
[0013] This invention provides a method for preparing a TX modifier, comprising the following steps:
[0014] (1) Slowly add mussel adhesive protein to the buffer solution, stir until fully dissolved, then add bamboo extract, stir and mix to form a mixed solution;
[0015] (2) Add tyrosinase to the mixed solution and seal and shake to react, forming a viscous biomimetic prepolymer solution;
[0016] (3) Add aminocellulose nanofibers to water and disperse them evenly to obtain an aminocellulose nanofiber suspension;
[0017] (4) Continue stirring the aminocellulose nanofiber suspension and slowly add polydimethylsiloxane triol to it; after the addition is complete, adjust the pH to 5.0-5.5 to obtain a mixed suspension;
[0018] (5) Add organotin catalyst to the mixed suspension for catalysis and stir the reaction to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0019] (6) After the reaction is complete, collect the precipitate to obtain the composite wet material;
[0020] (7) Disperse the composite wet material in water, and slowly and evenly add the viscous biomimetic prepolymer liquid prepared in step (2), stirring to form a uniform composite slurry;
[0021] (8) Dry the composite slurry to obtain the TX modifier.
[0022] Preferably, in step (1), the bamboo extract is prepared by washing the bamboo leaves, adding water, heating and extracting, and concentrating the extract to obtain the bamboo extract.
[0023] Preferably, in step (1), the buffer solution is a phosphate buffer solution.
[0024] More preferably, the pH of the phosphate buffer solution is 6.8 ± 0.2.
[0025] Preferably, in step (3), the preparation method of aminocellulose nanofibers is to activate the hydroxylated cellulose nanofiber dispersion with 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide catalysts; then condense it with ethylenediamine, and after purification, aminocellulose nanofibers are obtained.
[0026] Preferably, in step (4), the pH is adjusted to 5.0-5.5 with acetic acid.
[0027] More preferably, the mass fraction of acetic acid is 5%.
[0028] Preferably, in step (5), the organotin catalyst is dibutyltin dilaurate.
[0029] Preferably, in step (5), the amount of dibutyltin dilaurate is 0.1-0.2 parts.
[0030] The basic principle of this invention is as follows: A three-dimensional nano-reinforced framework constructed with aminocellulose nanofibers provides excellent physical filling and initial reinforcement effects. On this framework, tyrosinase specifically catalyzes the oxidative cross-linking of mussel adhesive protein and phenolic substances in bamboo extract to form a strong and tough biomimetic network. Through the abundant active groups such as catechol on this network, multiple chemical bonds are formed with the surface of fly ash and hydration products, achieving strong interfacial anchoring. In addition, the silanol groups of polydimethylsiloxane triol undergo a condensation reaction with the active groups in the system, forming a strong hydrophobic protective layer at the pores and interfaces, thereby improving the mechanical properties and durability such as freeze-thaw resistance of ultra-high fly ash cement-based materials.
[0031] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) Based on the demand for solid waste resource utilization, the present invention prepares high-strength, high-freezing-resistant, ultra-high content fly ash cement-based materials with fly ash content of up to 70%, which can be sourced locally in Inner Mongolia and other regions. This not only greatly reduces the cost of raw materials, but also helps to solve the problem of fly ash accumulation in Inner Mongolia and other regions. It is of great significance for energy conservation, carbon reduction and environmental protection.
[0032] (2) Compared with the prior art, the present invention, through a multi-level synergistic system of "nano-skeleton reinforcement - biomimetic network anchoring - hydrophobic encapsulation of pores", not only significantly improves the strength of ultra-high fly ash cement-based materials, but also comprehensively enhances their durability, such as freeze-thaw resistance, by synergistically regulating the hydration process and refining the pores. Therefore, the high-strength, high-freeze-resistant ultra-high fly ash cement-based materials prepared by the present invention have good reliability and engineering applicability, and can meet the requirements for strength and freeze-thaw resistance in practical engineering applications. Detailed Implementation
[0033] The present invention will now be described in further detail. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.
[0034] Unless otherwise specified, the following raw materials are used in the embodiments and comparative examples of this invention:
[0035] The bamboo extract was prepared by the following method: after washing the bamboo leaves, deionized water was added at a mass ratio of 1:10, heated to 80 ℃ and maintained for 1 h, filtered, and the filtrate was concentrated to 1 / 3 to obtain the extract.
[0036] Aminocellulose nanofibers were prepared by the following method: (1) 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide catalysts were added to a hydroxylated cellulose nanofiber dispersion with a solid content of 0.5%, and stirred for 2 h to fully activate the hydroxyl groups; the amount of 1-ethyl-(3-dimethylaminopropyl)carbodiimide was twice the amount of hydroxyl groups on the surface of the hydroxylated cellulose nanofibers, and the amount of N-hydroxysuccinimide was once the amount of hydroxyl groups on the surface of the hydroxylated cellulose nanofibers. (2) Excess ethylenediamine was added to the activated system, the pH was adjusted to 7.5-8.5 with dilute sodium hydroxide solution, and stirring was continued for 24 h to ensure complete amidation reaction; the amount of ethylenediamine was 15-20 times the amount of hydroxyl groups on the surface of the hydroxylated cellulose nanofibers. (3) After purification, the colloid was freeze-dried to obtain the final product.
[0037] The cement is P·I 42.5 silicate cement; the fly ash is Grade I fly ash that meets the national standard requirements. The fine aggregate is river sand that passes through a 4.75 mm square sieve; the coarse aggregate is crushed stone with a continuous gradation of 5-20 mm particle size.
[0038] Polydimethylsiloxane triol was produced by Maclean Biotech Co., Ltd., item number P856624; mussel adhesive protein was produced by Aladdin Biotech Co., Ltd., item number rp212901; tyrosinase was produced by Aladdin Biotech Co., Ltd., item number T128536.
[0039] Example 1:
[0040] This embodiment provides a high-strength, high-freeze-resistant, ultra-high content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0041] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0042] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0043] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0044] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0045] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0046] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0047] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0048] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0049] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0050] Example 2
[0051] This embodiment provides a high-strength, high-freeze-resistant, ultra-high content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0052] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 20 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0053] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0054] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0055] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0056] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0057] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0058] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0059] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0060] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0061] Example 3
[0062] This embodiment provides a high-strength, high-freeze-resistant, ultra-high content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0063] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 15 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0064] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0065] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0066] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0067] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0068] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0069] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0070] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0071] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0072] Example 4
[0073] This embodiment provides a high-strength, high-freeze-resistant, ultra-high content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0074] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 25 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0075] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0076] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0077] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0078] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0079] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0080] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0081] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0082] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0083] Example 5
[0084] This embodiment provides a high-strength, high-freeze-resistant, ultra-high content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0085] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.5 parts tyrosinase. Its preparation process includes the following steps:
[0086] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0087] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0088] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0089] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0090] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0091] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0092] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0093] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0094] Example 6
[0095] This embodiment provides a high-strength, high-freeze-resistant, ultra-high-content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 24 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0096] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0097] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0098] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0099] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0100] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0101] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0102] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0103] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0104] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0105] Example 7
[0106] This embodiment provides a high-strength, high-freeze-resistant, ultra-high-content fly ash cement-based material, comprising the following components by mass parts: 100 parts cement, 233 parts fly ash, 34 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water.
[0107] The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase. Its preparation process includes the following steps:
[0108] (1) Slowly add mussel adhesive protein to 0.1 M phosphate buffer and stir magnetically at 150 rpm for 2 hours. After it is fully dissolved, add bamboo extract and stir magnetically for 30 minutes to form a mixed solution.
[0109] (2) Add tyrosinase to the mixed solution and seal the reaction vessel. Shake at a low speed of 50 rpm on a constant temperature shaker for 24 h to form a viscous biomimetic prepolymer liquid for later use.
[0110] (3) Add aminocellulose nanofibers to an appropriate amount of deionized water and disperse them for 15 min at a rate of 10,000 rpm using a high-speed shear disperser to ensure uniform fiber dispersion.
[0111] (4) Continue stirring the aminocellulose nanofiber suspension at a rate of 600 rpm and slowly add polydimethylsiloxane triol to the suspension; after the addition is complete, adjust the pH to 5.0-5.5 with dilute acetic acid;
[0112] (5) Add dibutyltin dilaurate to the suspension as a catalyst and stir continuously at 50 °C for 6 h to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction.
[0113] (6) After the reaction is complete, add excess ethanol to terminate the reaction, centrifuge at 8000 rpm for 15 min, collect the precipitate and wash it with ethanol more than three times to obtain the composite wet material.
[0114] (7) Add the composite wet material to deionized water and disperse it, and adjust the solid content to 3%; then slowly and evenly add the previously prepared viscous biomimetic prepolymer at a rate of 8000 rpm, and continue stirring for 1 h to form a uniform composite slurry.
[0115] (8) Dry the composite slurry at -55 ℃ for 48 h using a freeze vacuum drying oven, then pulverize it with a low temperature pulverizer and pass it through a 200 mesh sieve to obtain the final product.
[0116] Example 8
[0117] This embodiment provides a high-strength, high-freeze-resistant, ultra-high-content fly ash cementitious material, comprising the following components by mass: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 400 parts fine aggregate, 0 parts coarse aggregate, and 57 parts water. The composition and preparation method of the TX modifier are the same as in Example 1.
[0118] Example 9
[0119] This embodiment provides a high-strength, high-freeze-resistance, ultra-high content fly ash cementitious material, comprising the following components by mass: 67 parts cement, 266 parts fly ash, 14 parts TX modifier, 140 parts fine aggregate, 270 parts coarse aggregate, and 70 parts water. The composition and preparation method of the TX modifier are the same as in Example 1.
[0120] Comparative Example 1
[0121] Based on Example 1, but unlike Example 1, this comparative example prepared ordinary Portland cement normal concrete without the addition of fly ash. Specifically, the ordinary Portland cement normal concrete comprises the following components by mass parts: 133 parts cement, 210 parts fine aggregate, 390 parts coarse aggregate, and 60 parts water.
[0122] Comparative Example 2
[0123] Based on Example 1, unlike Example 1, this comparative example did not add TX modifier. Therefore, in order to ensure the fluidity of the ultra-high fly ash cementitious material mixture, the water content was increased. Specifically, the ultra-high fly ash cementitious material includes the following components by mass parts: 100 parts cement, 233 parts fly ash, 141 parts fine aggregate, 262 parts coarse aggregate, and 100 parts water.
[0124] Comparative Example 3
[0125] Based on Example 1, the difference is that the TX modifier in this comparative example did not contain aminocellulose nanofibers. Specifically, the ultra-high content fly ash cement-based material comprises the following components by weight: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water. The TX modifier comprises the following components by weight: 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase.
[0126] Comparative Example 4
[0127] Based on Example 1, the difference is that the TX modifier in this comparative example does not contain polydimethylsiloxane triol. Specifically, the ultra-high fly ash cement-based material comprises the following components by weight: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water. The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts mussel adhesive protein, and 1.0 part tyrosinase.
[0128] Comparative Example 5
[0129] Based on Example 1, the difference is that the TX modifier in this comparative example does not contain mussel adhesive protein. Specifically, the ultra-high content fly ash cement-based material comprises the following components by weight: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water. The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, and 1.0 part tyrosinase.
[0130] Comparative Example 6
[0131] Based on Example 1, the difference is that bamboo extract was not added to the TX modifier in this comparative example. Specifically, the ultra-high fly ash cement-based material comprises the following components by weight: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water. The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase.
[0132] Comparative Example 7
[0133] Based on Example 1, the difference is that the TX modifier in this comparative example did not contain tyrosinase. Specifically, the ultra-high fly ash cement-based material comprises the following components by weight: 100 parts cement, 233 parts fly ash, 14 parts TX modifier, 141 parts fine aggregate, 262 parts coarse aggregate, and 57 parts water. The TX modifier comprises the following components by weight: 50 parts aminocellulose nanofibers, 15 parts bamboo extract, 10 parts polydimethylsiloxane triol, 10 parts mussel adhesive protein, and 1.0 part tyrosinase.
[0134] To test the mechanical properties and freeze-thaw resistance of the high-strength, high-freeze-resistance, ultra-high fly ash cementitious material of the present invention, ultra-high fly ash cementitious material mixtures were prepared according to the component dosages in the above embodiments and comparative examples, and molded into test blocks of 100×100×100 mm and 100×100×400 mm; compressive strength and freeze-thaw cycle tests were conducted according to the test methods specified in GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete" and GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete".
[0135] After the test blocks were cured to the appropriate age, compressive strength tests were conducted on the formed ultra-high fly ash cement-based material specimens. The compressive strengths of concrete in Examples 1-7 and Comparative Examples 1-7 were obtained, as shown in Table 1.
[0136] Table 1 Compressive strength of ultra-high fly ash cementitious materials
[0137]
[0138] As shown in Table 1, the ultra-high fly ash content cement-based material prepared by this invention possesses excellent strength properties. The 7-day compressive strength of this concrete ranges from 42.6 to 57.3 MPa, meeting the requirements for engineering applications with certain early-stage strength requirements. Furthermore, after converting its 28-day compressive strength into standard specimens of 150×150×150 mm, it reaches a strength grade of C60-C75. Despite a 70% cement substitution, its compressive strength is still higher than that of pure silicate cement concrete without fly ash, indicating its superior mechanical properties. Compared to the 28-day strength, the 90-day compressive strength increases by 11.92%-37.95%, demonstrating significant late-stage strength growth and stable performance, effectively ensuring the long-term load-bearing capacity of the constructed structure.
[0139] Meanwhile, the molded ultra-high fly ash cementitious material freeze-thaw resistance specimens were cured for 28 days and then subjected to freeze-thaw cycle tests. The freeze-thaw resistance test data of the ultra-high fly ash cementitious materials in Examples 1-7 and Comparative Examples 1-7 are shown in Table 2.
[0140] Table 2 Mass loss and relative dynamic elastic modulus of ultra-high fly ash cementitious materials in frost resistance test
[0141]
[0142] [Note]: After the first 25 freeze-thaw cycles, the relative dynamic elastic modulus of Comparative Example 2 was 56.3%, which was less than 60%, so the results are not shown in Table 2.
[0143] As shown in Table 2, the ultra-high fly ash content cement-based material prepared by this invention possesses excellent frost resistance. After 400 freeze-thaw cycles, the mass loss of Examples 1-7 did not exceed 5%, and the relative dynamic modulus of elasticity was significantly higher than 60%. Therefore, this concrete has a frost resistance grade of F400, making it suitable for severely cold and frigid regions such as Inner Mongolia, as well as engineering structures with extremely high requirements for frost resistance.
[0144] In summary, the ultra-high fly ash content cement-based material prepared by this invention exhibits excellent mechanical properties and frost resistance, possesses good reliability and engineering applicability, and can meet the requirements for strength and frost resistance in practical engineering applications.
[0145] The foregoing has provided a detailed description of the preparation method and application of an ultra-high fly ash cement-based material provided by this invention. The embodiments described herein are specific explanations of the principles and implementation methods of this invention, serving to aid in understanding the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications based on the core ideas of this invention without departing from its technical principles, and these improvements and modifications should also be considered within the scope of protection of this invention.
Claims
1. A high-strength, high-frost-resistant, ultra-high-content fly ash cement-based material, characterized in that, It includes the following components by weight: 67-100 parts cement, 233-266 parts fly ash, 14-34 parts TX modifier, 140-400 parts fine aggregate, 0-270 parts coarse aggregate, and 57-70 parts water; the TX modifier includes the following components by weight: 50 parts aminocellulose nanofibers, 15-25 parts bamboo extract, 10-20 parts polydimethylsiloxane triol, 10-15 parts mussel adhesive protein, and 1.0-1.5 parts tyrosinase.
2. The cement-based material according to claim 1, characterized in that, The aminocellulose nanofibers have a solid content of 2% and an amino content of not less than 0.8 mmol / g.
3. The cement-based material according to claim 1, characterized in that, The hydroxyl value of the polydimethylsiloxane triol is not less than 3%; the enzyme activity of the tyrosinase is not less than 1000 U / mg.
4. The cement-based material according to claim 1, characterized in that, The cement is P·I 42.5 silicate cement, and the fine aggregate is river sand.
5. The cement-based material according to claim 1, characterized in that, The TX modifier was prepared by the following steps: (1) Slowly add mussel adhesive protein to the buffer solution, stir until fully dissolved, then add bamboo extract, stir and mix to form a mixed solution; (2) Add tyrosinase to the mixed solution and seal and shake to react, forming a viscous biomimetic prepolymer solution; (3) Add aminocellulose nanofibers to water and disperse them evenly to obtain an aminocellulose nanofiber suspension; (4) Continue stirring the aminocellulose nanofiber suspension and slowly add polydimethylsiloxane triol to it; after the addition is complete, adjust the pH to 5.0-5.5 to obtain a mixed suspension; (5) Add organotin catalyst to the mixed suspension for catalysis and stir the reaction to allow aminocellulose nanofibers and polydimethylsiloxane triol to undergo a full condensation reaction. (6) After the reaction is complete, collect the precipitate to obtain the composite wet material; (7) Disperse the composite wet material in water, and slowly and evenly add the viscous biomimetic prepolymer liquid prepared in step (2), stirring to form a uniform composite slurry; (8) Dry the composite slurry to obtain the TX modifier.
6. The cement-based material according to claim 5, characterized in that, In step (1), the bamboo extract is prepared by washing the bamboo leaves, adding water, heating and extracting, and concentrating the extract to obtain the bamboo extract.
7. The cement-based material according to claim 5, characterized in that, In step (1), the buffer solution is phosphate buffer.
8. The cement-based material according to claim 5, characterized in that, In step (4), the pH is adjusted to 5.0-5.5 with acetic acid.
9. The cement-based material according to claim 5, characterized in that, In step (5), the organotin catalyst is dibutyltin dilaurate.
10. The cement-based material according to claim 9, characterized in that, In step (5), the amount of dibutyltin dilaurate is 0.1-0.2 parts.