High-performance fiber-reinforced cement-based material and preparation method thereof

Abstract

The invention provides a high-performance fiber-reinforced cement-based material and a preparation method thereof, and belongs to the technical field of building materials, the high-performance fiber-reinforced cement-based material comprises the following components by weight: 30-70% of ordinary Portland cement, 10-30% of pretreated solid waste incineration bottom ash, 0.5-2% of polypropylene fiber, 8-12% of water, and 0.5-1.5% of a water reducer; during preparation, the raw materials are weighed according to the proportion, a high-performance fiber-reinforced cement-based material sample is prepared through ultrasonic stirring, water adding stirring, fluidity adjusting, pouring vibrating and curing, the compressive strength of the prepared sample exceeds 30 MPa, the porosity is lower than that of a traditional material when the replacement rate of the pretreated solid waste incineration bottom ash is 5-10%, and the durability is remarkably improved; meanwhile, waste is effectively utilized, natural resource consumption and carbon emission are reduced, the curing efficiency of heavy metal ions in solid waste incineration bottom ash exceeds 98%, and double breakthrough of environmental protection and high performance is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a high-performance fiber-reinforced cement-based material and a preparation method thereof. Background Art

[0002] In the continuous development of the construction industry, the demand for high-performance building materials is increasing day by day. Due to performance limitations, traditional cement-based materials are difficult to meet the stringent requirements of current construction projects for high strength, high durability and environmental protection. In terms of strength, ordinary cement-based materials have insufficient compressive strength when facing large-scale building structures, bridges and other projects with extremely high load-bearing capacity requirements. For example, in the infrastructure construction of some super-high-rise buildings, traditional cement-based materials are prone to deformation, cracking and other conditions after being under great pressure for a long time, which seriously affects the stability and safety of the building.

[0003] Durability is also a major shortcoming of existing cement-based materials. In harsh environments such as humidity, acid and alkali corrosion, the porosity of ordinary cement-based materials is relatively high, making it easy for external corrosive media to invade the interior, accelerating the degradation of the material and significantly shortening the service life of the building. Taking buildings in coastal areas as an example, due to long-term erosion by seawater, the walls, structural components and other parts of traditional cement-based materials are prone to corrosion. And from an environmental protection perspective, the production process of traditional cement-based materials not only consumes a large amount of natural resources, such as limestone, but also releases a large amount of carbon dioxide, which imposes a heavy burden on the environment. At the same time, the treatment of waste such as bottom ash from the incineration of municipal solid waste has always been a difficult problem in the field of environmental protection. In the past, landfill or simple stacking was mostly used, which not only occupied a large amount of land resources, but also had potential environmental pollution risks, such as the seepage of heavy metal ions to pollute the soil and groundwater. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a high-performance fiber-reinforced cement-based material and a preparation method thereof, which transforms the bottom ash from solid waste incineration into treasure, thereby not only reducing dependence on natural resources and reducing carbon emissions, but also realizing the resource utilization of waste.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A high-performance fiber-reinforced cementitious material contains the following components by weight percentage: ordinary Portland cement 30-70%, pretreated solid waste incineration bottom ash 10-30%, polypropylene fiber 0.5-2%, water 8-12%, water reducer 0.5-1.5%, and the sum of each component is 100%; the pretreatment process of the solid waste incineration bottom ash is as follows: first, place the solid waste incineration bottom ash MSWIBA in an oven at 105°C for drying until its weight reaches a constant weight state; then put the dried MSWIBA into a ball mill for ball milling for 30-60 minutes and screening, and the particles with a particle size less than 0.15 mm are used to replace cement, and the particles with a particle size of 0.15-1.15 mm are used as fine aggregate; finally, remove magnetic impurities by magnetic separation and separate light impurities and harmful components by flotation to obtain the pretreated solid waste incineration bottom ash.

[0007] Preferably, the polypropylene fiber has a length of 12 mm and a diameter of 25 μm.

[0008] Preferably, the water reducer is a polycarboxylate water reducer with a solid content of 20%.

[0009] The present invention also provides a preparation method of the above high-performance fiber-reinforced cementitious material, including the following steps:

[0010] S1. Obtain the solid waste incineration bottom ash, and classify and store it for use after detecting its chemical and physical properties.

[0011] S2. Weigh ordinary Portland cement, solid waste incineration bottom ash with different particle sizes, and polypropylene fiber according to the designed weight percentage, mix them and put them into an ultrasonic mixer for stirring to preliminarily disperse the polypropylene fiber and break the agglomeration structure.

[0012] S3. Add water to the ultrasonic mixer and continue stirring. After the stirring is completed, measure the fluidity of the mixture, and optimize it by adjusting the dosage of the water reducer or the water-cement ratio according to the test results.

[0013] S4. Pour the prepared mixture into a test mold, vibrate it with a vibrating table, and cover the surface of the test mold with plastic wrap after pouring.

[0014] S5. Demold the test mold after placing it for 1-2 days, and cure the demolded sample according to the predetermined curing method to finally obtain a high-performance fiber-reinforced cementitious material sample.

[0015] Preferably, in S1, the detection of the chemical and physical properties of the solid waste incineration bottom ash includes heavy metal content and chemical composition fluctuation, and the physical property detection indexes include particle size distribution and density. Classify and store them according to the detection results and the principle of similar chemical composition stability and physical properties.

[0016] Preferably, in S2, the ultrasonic power of the ultrasonic stirrer is 500-1000W, and the stirring time is 2-4min, so as to ensure that the polypropylene fibers are fully dispersed and not over-damaged.

[0017] Preferably, in S3, the fluidity test range is 160mm-200mm;

[0018] If the fluidity of the mixture is lower than 160mm, first increase the dosage of water reducer by 0.1%-0.2% each time, then remix and test the fluidity of the mixture. If the fluidity does not improve after increasing the water reducer, increase the amount of water and adjust the water-cement ratio at the same time, with the water-cement ratio increasing by 0.05-0.1 each time;

[0019] If the fluidity of the mixture is higher than 200mm, first reduce the amount of water by 0.5%-1% of the total weight of the mixture each time, continue to test the fluidity of the mixture after stirring. If the reduction effect is not obvious, reduce the dosage of water reducer by 0.1-0.3% each time.

[0020] Preferably, in S4, the vibration frequency of the vibrating table is 50-100Hz, and the vibration time is 1-3min, so as to ensure that the mixture is uniform and dense during the pouring process.

[0021] Preferably, in S5, the curing method includes one of standard curing, water bath curing and supersaturated calcium hydroxide solution curing. The temperature of the standard curing is 18-22°C, and the humidity is greater than 95%; the temperature of the water bath curing is 20-80°C, and the humidity is 100%; the temperature of the supersaturated calcium hydroxide solution curing is 18-22°C, and the humidity is 100%.

[0022] Preferably, the compressive strength of the high-performance fiber-reinforced cement-based material is greater than 30MPa. When the substitution rate of solid waste incineration bottom ash is 5-10%, the porosity is lower than that of the cement-based material without using solid waste incineration bottom ash. As the substitution rate of solid waste incineration bottom ash increases, the physical and chemical energy and carbon emissions are lower than those of the cement-based material without using solid waste incineration bottom ash, and the solidification efficiency of heavy metal ions in solid waste incineration bottom ash is higher than 98%.

[0023] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0024] (1) The high-performance fiber-reinforced cement-based material of the present invention optimizes the material composition, such as setting the ratios of ordinary Portland cement, pretreated solid waste incineration bottom ash, and polypropylene fibers, etc., and combines preparation processes such as ultrasonic stirring and precise vibration to make the compressive strength of the material exceed 30 MPa. It can effectively avoid deformation, cracking, etc. caused by long-term heavy pressure in scenarios such as the foundation construction of super high-rise buildings, and greatly improve the stability and safety of buildings.

[0025] (2) Through the pretreatment process, the present invention effectively utilizes the solid waste incineration bottom ash, reduces the dependence on natural resources such as limestone, and reduces carbon emissions. At the same time, the solidification efficiency of heavy metal ions in the bottom ash is higher than 98%, avoiding the risk of heavy metal ion seepage pollution of soil and groundwater caused by landfill or simple stacking, realizing the resource utilization of waste, and greatly reducing the environmental burden.

[0026] (3) When the substitution rate of the solid waste incineration bottom ash in the present invention is 5-10%, the porosity is lower than that of the cement-based material without using the bottom ash. The optimized microstructure effectively prevents the intrusion of external erosion media, and greatly improves the durability of the material in harsh environments. For example, for buildings in coastal areas that are long-term eroded by seawater, this material can better resist corrosion and extend the service life of buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a flowchart of a preparation method of a high-performance fiber-reinforced cement-based material of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0031] Such as Figure 1As shown in the figure, the present invention provides a preparation method of a high-performance fiber-reinforced cement-based material, comprising the following steps:

[0032] S1. Obtain the incineration bottom ash of solid waste, and classify and store it for use after detecting its chemical and physical properties;

[0033] S2. Weigh ordinary Portland cement, incineration bottom ash of solid waste with different particle sizes, and polypropylene fiber according to the designed weight percentages, mix them and put them into an ultrasonic mixer for stirring to preliminarily disperse the polypropylene fiber and break the agglomeration structure;

[0034] Among them, the raw materials contain the following components by weight percentage: 30-70% of ordinary Portland cement, 10-30% of pretreated incineration bottom ash of solid waste, 0.5-2% of polypropylene fiber, 8-12% of water, 0.5-1.5% of water reducer, and the sum of each component is 100%; the pretreatment process of the incineration bottom ash of solid waste is as follows: first, place the municipal solid waste incineration bottom ash (MSWIBA) in an oven at 105°C for drying until its weight reaches a constant weight state; then put the dried MSWIBA into a ball mill for ball milling for 30-60 minutes and screening, and the particles with a particle size less than 0.15 mm are used to replace cement, and the particles with a particle size of 0.15-1.15 mm are used as fine aggregates; finally, remove magnetic impurities by magnetic separation and separate light impurities and harmful components by flotation to obtain the pretreated incineration bottom ash of solid waste. The length of the polypropylene fiber is 12 mm and the diameter is 25 μm. The water reducer is a polycarboxylate water reducer with a solid content of 20%.

[0035] S3. Add water to the ultrasonic mixer and continue stirring. After the stirring ends, test the fluidity of the mixture, and optimize it by adjusting the dosage of the water reducer or the water-cement ratio according to the test results;

[0036] S4. Pour the prepared mixture into a test mold, vibrate it with a vibrating table, and cover the surface of the test mold with plastic wrap after pouring;

[0037] S5. Demold the test mold after placing it for 1-2 days, and cure the demolded sample according to the predetermined curing method to finally obtain a high-performance fiber-reinforced cement-based material sample.

[0038] According to the above content, in S1, the detection of the chemical and physical properties of the incineration bottom ash of solid waste includes heavy metal content and chemical composition fluctuation, and the physical property detection indexes include particle size distribution and density. Classification storage is carried out according to the detection results and the principle of similar chemical composition stability and physical properties. In S2, the ultrasonic power of the ultrasonic mixer is 500-1000 W, and the stirring time is 2-4 minutes to ensure that the polypropylene fiber is fully dispersed and not overly damaged.

[0039] In addition, in S3, the slump test range is 160 mm to 200 mm;

[0040] If the slump of the mixture is lower than 160 mm, first increase the dosage of water reducer by 0.1% - 0.2% each time, then remix and test the slump of the mixture. If the slump does not improve after increasing the water reducer, increase the water dosage and adjust the water-cement ratio simultaneously, with the water-cement ratio increasing by 0.05 - 0.1 each time;

[0041] If the slump of the mixture is higher than 200 mm, first reduce the water dosage by 0.5% - 1% of the total weight of the mixture each time, remix and continue to test the slump of the mixture. If the reduction effect is not obvious, reduce the water reducer dosage by 0.1 - 0.3% each time.

[0042] In S4, the vibration frequency of the vibrating table is 50 - 100 Hz, and the vibration time is 1 - 3 min to ensure the mixture is uniform and dense during pouring. In S5, the curing method includes one of standard curing, water bath curing, and supersaturated calcium hydroxide solution curing. The temperature of the standard curing is 18 - 22 °C, and the humidity is greater than 95%; the temperature of the water bath curing is 20 - 80 °C, and the humidity is 100%; the temperature of the supersaturated calcium hydroxide solution curing is 18 - 22 °C, and the humidity is 100%.

[0043] The high-performance fiber-reinforced cementitious material prepared according to the above preparation method has a compressive strength greater than 30 MPa, a porosity lower than that of the cementitious material without using solid waste incineration bottom ash when the substitution rate of solid waste incineration bottom ash is 5 - 10%, and with the increase of the substitution rate of solid waste incineration bottom ash, the physical and chemical energy and carbon emissions are lower than those of the cementitious material without using solid waste incineration bottom ash, and the solidification efficiency of heavy metal ions in the solid waste incineration bottom ash is higher than 98%.

[0044] The following is a further verification and explanation of the above content through specific implementation methods. The numerical values of the process conditions taken in the following examples and comparative examples are all exemplary, and the range of values that can be taken is as shown in the foregoing content.

[0045] Example 1

[0046] In this example, the raw material composition for preparing the high-performance fiber-reinforced cementitious material is by weight percentage: 60% ordinary Portland cement, 20% pretreated solid waste incineration bottom ash, 1% polypropylene fiber, 10% water, and 0.5% polycarboxylate water reducer, and the remaining part adjusts the proportion of ordinary Portland cement to 8.5%.

[0047] The method for preparing the high-performance fiber-reinforced cementitious material according to the above raw materials includes the following steps:

[0048] (1) Obtain the incineration bottom ash of solid waste and conduct comprehensive chemical and physical property tests on it, including heavy metal content, chemical composition fluctuation, particle size distribution, density, etc. Classify and store the bottom ash according to the principle of similar chemical composition stability and physical properties.

[0049] (2) Accurately weigh ordinary Portland cement, pre-treated incineration bottom ash of solid waste with different particle sizes (place the incineration bottom ash of solid waste in an oven at 105 °C and dry it to a constant weight, then put it into a ball mill and mill for 45 minutes and screen it, so that the particles with a particle size less than 0.15 mm are used to replace cement, and the particles with a particle size of 0.15 - 1.15 mm are used as fine aggregate, and finally remove magnetic impurities by magnetic separation and separate light impurities and harmful components by flotation) and polypropylene fiber. Mix them and then place them in an ultrasonic mixer. Set the ultrasonic power to 800 W and the stirring time to 3 minutes to fully disperse the polypropylene fiber and simultaneously break its agglomeration structure.

[0050] (3) Add water to the ultrasonic mixer and continue stirring. After the stirring ends, test the fluidity of the mixture. Suppose the measured fluidity is 180 mm, which is in the ideal range of 160 mm - 200 mm, and no adjustment is required.

[0051] (4) Pour the prepared mixture into a test mold and vibrate it using a vibrating table. The vibration frequency is 80 Hz and the vibration time is 2 minutes. After pouring, cover the surface of the test mold with plastic wrap to prevent the rapid evaporation of water.

[0052] (5) Leave the test mold for 1.5 days and then demold it. The demolded samples are cured using the standard curing method, that is, cured under the conditions of a temperature of 20 °C and a humidity greater than 95%, and finally obtain samples of high-performance fiber-reinforced cement-based materials.

[0053] After testing, the compressive strength of the fiber-reinforced cement-based material prepared in this example is 36 MPa. When the substitution rate of the incineration bottom ash of solid waste is 7%, the porosity is reduced by about 18% compared with the cement-based material without using the incineration fly ash of solid waste; at the same time, compared with the traditional cement-based material, the physical and chemical energy of the fiber-reinforced cement-based material prepared in this example is reduced by 14%, and the carbon emission is reduced by 16%; in addition, the solidification efficiency of heavy metal ions in this example can reach 98.8%.

[0054] Example 2

[0055] In this example, the raw material composition for preparing the high-performance fiber-reinforced cement-based material is by weight percentage: 55% ordinary Portland cement, 25% pre-treated incineration bottom ash of solid waste, 1.5% polypropylene fiber, 9% water, and 1% polycarboxylate water reducer, and the remaining part adjusts the proportion of ordinary Portland cement to 8.5%.

[0056] A method for preparing a high-performance fiber-reinforced cementitious material from the above raw materials, comprising the following steps:

[0057] (1) Obtain the incineration bottom ash of solid waste, conduct comprehensive chemical and physical property tests on it, including heavy metal content, chemical composition fluctuation, particle size distribution, density, etc., and classify and store the bottom ash according to the principle of similar chemical composition stability and physical properties.

[0058] (2) Accurately weigh ordinary Portland cement, pre-treated incineration bottom ash of solid waste with different particle sizes, and polypropylene fibers according to the above ratio, mix them and put them into an ultrasonic mixer, set the ultrasonic power to 750W, and the stirring time to 3.5min to fully disperse the polypropylene fibers and at the same time break its agglomerated structure.

[0059] (3) Add water to the ultrasonic mixer and continue stirring. After the stirring is completed, test the fluidity of the mixture. Suppose the measured fluidity is 172mm, slightly lower than the lower limit of the ideal range. Increase the dosage of the water reducer to 1.2%, and the fluidity reaches 178mm after re-stirring.

[0060] (4) Pour the prepared mixture into a test mold, vibrate it using a vibrating table, the vibration frequency is 75Hz, and the vibration time is 2min. After pouring, cover the surface of the test mold with plastic wrap to prevent the water from evaporating too quickly.

[0061] (5) Leave the test mold for 1.3 days and then demold it. The demolded sample is cured by water bath, that is, cured under the conditions of a temperature of 60°C and a humidity of 100%, and finally a sample of high-performance fiber-reinforced cementitious material is obtained.

[0062] After testing, the compressive strength of the fiber-reinforced cementitious material prepared in this example is 39MPa. When the substitution rate of the incineration bottom ash of solid waste is 8.3%, the porosity is reduced by about 20% compared with the cementitious material without using the incineration fly ash of solid waste; at the same time, compared with the traditional cementitious material, the physical and chemical energy of the fiber-reinforced cementitious material prepared in this example is reduced by 16%, and the carbon emission is reduced by 18%; in addition, the solidification efficiency of heavy metal ions in this example can reach 99%.

[0063] Example 3

[0064] In this example, the raw material composition for preparing the high-performance fiber-reinforced cementitious material is by weight percentage: 50% ordinary Portland cement, 30% pre-treated incineration bottom ash of solid waste, 2% polypropylene fiber, 8% water, and 1.5% polycarboxylate water reducer, and the remaining part adjusts the proportion of ordinary Portland cement to 8.5%.

[0065] A method for preparing a high-performance fiber-reinforced cementitious material from the above raw materials, comprising the following steps:

[0066] (1) Obtain the incineration bottom ash of solid waste, and conduct comprehensive chemical and physical property tests on it, including heavy metal content, chemical composition fluctuation, particle size distribution, density, etc. Classify and store the bottom ash according to the principle of similar chemical composition stability and physical properties.

[0067] (2) Accurately weigh ordinary Portland cement, pre-treated incineration bottom ash of solid waste with different particle sizes, and polypropylene fiber according to the above ratio, mix them and then put them into an ultrasonic mixer. Set the ultrasonic power to 900W and the stirring time to 4min to fully disperse the polypropylene fiber and at the same time break its agglomeration structure.

[0068] (3) Add water to the ultrasonic mixer and continue stirring. After stirring, test the fluidity of the mixture. Suppose the measured fluidity is 192mm, slightly higher than the lower limit of the ideal range. First, reduce the water dosage to 7.5%, and the fluidity reaches 185mm after re-stirring.

[0069] (4) Pour the prepared mixture into a test mold, and use a vibrating table for vibration. The vibration frequency is 90Hz and the vibration time is 1.5min. After pouring, cover the surface of the test mold with plastic wrap to prevent the water from evaporating too quickly.

[0070] (5) Leave the test mold for 1.8 days and then demold. The demolded sample is cured with supersaturated calcium hydroxide solution, that is, cured under the conditions of a temperature of 22°C and a humidity of 100%, and finally a high-performance fiber-reinforced cement-based material sample is obtained.

[0071] After testing, the compressive strength of the fiber-reinforced cement-based material prepared in this example is 42MPa. When the substitution rate of the incineration bottom ash of solid waste is 10%, the porosity is reduced by about 23% compared with the cement-based material without using the incineration fly ash of solid waste; at the same time, compared with the traditional cement-based material, the physical and chemical energy of the fiber-reinforced cement-based material prepared in this example is reduced by 20%, and the carbon emission is reduced by 22%; in addition, the solidification efficiency of heavy metal ions in this example can reach 99.3%.

[0072] Comparative Example 1

[0073] The raw material composition of this comparative example does not add polypropylene fiber. The material composition is: 70% ordinary Portland cement, 20% pre-treated incineration bottom ash of solid waste, 9% water, and 1% polycarboxylate water reducer. The preparation method adopted is the same as that of Example 1. After testing, the compressive strength of the material prepared in this comparative example is 30MPa. When the substitution rate of the incineration bottom ash of solid waste is 7%, the porosity is about 32% higher than that of Example 1; at the same time, compared with Example 1, the physical and chemical energy of the fiber-reinforced cement-based material prepared in this comparative example is lower, but due to the lack of polypropylene fiber, the crack resistance decreases and the structural durability decreases; in addition, the solidification efficiency of heavy metal ions in this comparative example can reach 98%.

[0074] Comparative Example 2

[0075] In this comparative example, no pretreatment was carried out on the solid waste incineration bottom ash. The material composition was: 65% ordinary Portland cement, 20% untreated solid waste incineration bottom ash, 1% polypropylene fiber, 10% water, 0.5% polycarboxylate water reducer, and the remaining part adjusted the proportion of ordinary Portland cement to 3.5%. The preparation method used included: obtaining the solid waste incineration bottom ash, without drying, ball milling, magnetic separation, and flotation treatment, and directly using it. Weigh the raw materials according to the proportion, and perform ultrasonic stirring with an ultrasonic power of 800W and a stirring time of 3 min; add water and water reducer and stir to adjust the fluidity of the mixture; through pouring, vibrating, and covering, and finally demolding and curing are the same as in Example 1 to obtain a fiber-reinforced cement-based material sample.

[0076] After testing, the compressive strength of the fiber-reinforced cement-based material prepared in this comparative example was 32 MPa. When the substitution rate of the solid waste incineration bottom ash was 7%, the porosity was about 40% higher than that in Example 1; at the same time, compared with Example 1, the physical and chemical energy and carbon emissions of the fiber-reinforced cement-based material prepared in this comparative example did not decrease significantly and increased due to more impurities; in addition, the solidification efficiency of heavy metal ions in this comparative example was only 85% because the untreated bottom ash contained more impurities, which affected the solidification effect.

[0077] Comparative Example 3

[0078] This comparative example was prepared using a different water reducer. The material composition was: 62% ordinary Portland cement, 20% pretreated solid waste incineration bottom ash, 1% polypropylene fiber, 10% water, 1.5% naphthalene-based water reducer, and the solid content was 30%; the remaining part adjusted the proportion of ordinary Portland cement to 5.5%. The preparation method used included: the same as in Example 1; weigh the raw materials according to the proportion, and perform ultrasonic stirring with an ultrasonic power of 800W and a stirring time of 3 min; add water and naphthalene-based water reducer and stir to adjust the fluidity of the mixture; through pouring, vibrating, and covering, and finally demolding and curing are the same as in Example 1 to obtain a fiber-reinforced cement-based material sample.

[0079] After testing, the compressive strength of the material prepared in this comparative example was 33 MPa. When the substitution rate of the solid waste incineration bottom ash was 7%, the porosity was about 28% higher than that in Example 1; at the same time, the physical and chemical energy and carbon emissions were close to those in Example 1, but due to the different performance of the naphthalene-based water reducer, the workability was poor, which affected the construction convenience; in addition, the solidification efficiency of heavy metal ions in this comparative example reached 98.2%.

[0080] Comparative Example 4

[0081] This comparative example was prepared using different curing methods. The material composition was: 60% ordinary Portland cement, 20% pretreated solid waste incineration bottom ash, 1% polypropylene fiber, 10% water, 0.5% polycarboxylate superplasticizer, with a solid content of 20%; the remaining part adjusted the proportion of ordinary Portland cement to 8.5%. The preparation method used was the same as that in Example 1, except that demolding and curing were carried out in the natural environment to obtain a fiber-reinforced cement-based material sample.

[0082] After testing, the compressive strength of the material prepared in this comparative example was 34 MPa. When the substitution rate of solid waste incineration bottom ash was 7%, the porosity was about 35% higher than that in Example 1; at the same time, the physical and chemical energy and carbon emissions were close to those in Example 1, but due to different curing conditions, the durability decreased, resulting in poor long-term performance; in addition, the curing efficiency of heavy metal ions in this comparative example could reach 98.5%.

[0083] Through the comparative analysis of the performance test results of Examples 1 to 3 and Comparative Examples 1 to 4, it can be seen that the high-performance fiber-reinforced cement-based material and its preparation method of the present invention have shown outstanding technical effects. In the specific embodiments, the materials all exhibited relatively high compressive strengths, such as 36 MPa in Example 1, 39 MPa in Example 2, and 42 MPa in Example 3, and with the reasonable ratio adjustment of components such as pretreated solid waste incineration bottom ash and polypropylene fiber, the strength advantage was obvious. At the same time, the porosity of the materials was significantly reduced, which could be reduced by about 18% to 23% compared with the materials without using the present invention in different embodiments, greatly enhancing the durability and impermeability of the materials. The reduction ranges of physical and chemical energy and carbon emissions were between 14% and 22%, highlighting the environmental protection advantages, and the curing efficiency of heavy metal ions was as high as 98.8% to 99.3%, effectively solving the environmental pollution risk. The four comparative examples, on the contrary, proved the importance of each key element of the present invention. In Comparative Example 1, the absence of fiber addition reduced the compressive strength and increased the porosity; in Comparative Example 2, the bottom ash was not pretreated, resulting in a decrease in compressive strength, a significant increase in porosity, and a low curing efficiency of heavy metal ions; in Comparative Example 3, different superplasticizers were used, affecting the compressive strength and porosity; in Comparative Example 4, changing the curing conditions led to a decrease in compressive strength and an increase in porosity. These comparisons fully illustrate that the present invention has significant advantages in improving material performance, enhancing structural durability, realizing environmental protection and resource utilization, and ensuring structural safety.

[0084] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0085] In this article, specific examples are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A high-performance fiber-reinforced cement-based material, characterized in that: The invention comprises the following components by weight percentage: 30-70% of ordinary silicate cement, 10-30% of pretreated solid waste incineration bottom ash, 0.5-2% of polypropylene fiber, 8-12% of water, and 0.5-1.5% of water reducer, and the sum of the components is 100%. The pretreatment process of the solid waste incineration bottom ash is as follows: firstly, the solid waste incineration bottom ash MSWIBA is placed in an oven at 105°C for drying until its weight reaches a constant weight state; then, the dried MSWIBA is placed in a ball mill for ball milling for 30-60 minutes and sieved, and particles with a particle size of less than 0.15 mm are used to replace cement, and particles with a particle size of 0.15-1.15 mm are used as fine aggregates; finally, magnetic impurities are removed by magnetic separation, and light impurities and harmful components are separated by flotation, so as to obtain the pretreated solid waste incineration bottom ash.

2. A high performance fiber reinforced cement-based material according to claim 1, characterized in that: The polypropylene fiber has a length of 12 mm and a diameter of 25 μm.

3. A high performance fiber reinforced cement-based material according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer with a solid content of 20%.

4. A method for preparing a high-performance fiber-reinforced cement-based material according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Obtaining solid waste incineration bottom ash, and performing chemical and physical property tests on the solid waste incineration bottom ash before classification, storage and use; S2. Ordinary Portland cement, solid waste incineration bottom ash of different particle sizes and polypropylene fibers are weighed according to the designed weight percentage, mixed and placed in an ultrasonic mixer for stirring to preliminarily disperse the polypropylene fibers and destroy the agglomeration structure; S3, adding water to the ultrasonic mixer and continuing stirring, testing the fluidity of the mixture after stirring, and optimizing it by adjusting the amount of water reducing agent or water-cement ratio according to the test results; S4, pouring the prepared mixture into a test mold and vibrating it on a vibration table. After pouring, cover the surface of the test mold with plastic wrap; S5. Place the test mold for 1 to 2 days and then demould it. The demoulded sample is cured according to a predetermined curing method to finally obtain a high-performance fiber-reinforced cement-based material sample.

5. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: In S1, the solid waste incineration bottom ash is subjected to chemical and physical property tests including heavy metal content and chemical composition fluctuations, and physical property test indicators including particle grading and density. According to the test results and in accordance with the principle of chemical composition stability and similar physical properties, the bottom ash is classified and stored.

6. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: In S2, the ultrasonic power of the ultrasonic stirrer is 500-1000W, and the stirring time is 2-4 minutes to ensure that the polypropylene fibers are fully dispersed and not excessively damaged.

7. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: In S3, the fluidity test range is 160 mm to 200 mm; If the fluidity of the mixture is less than 160mm, first increase the amount of water reducer by 0.1% to 0.2% each time, then re-stir and test the fluidity of the mixture. If the fluidity does not improve after adding the water reducer, increase the amount of water and adjust the water-cement ratio by 0.05 to 0.1 each time. If the fluidity of the mixture is higher than 200mm, first reduce the amount of water, each time reducing 0.5% to 1% of the total weight of the mixture, and continue to test the fluidity of the mixture after stirring. If the reduction effect is not obvious, reduce the amount of water reducer, each time reducing 0.1 to 0.3%.

8. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: In S4, the vibration frequency of the vibration table is 50-100 Hz, and the vibration time is 1-3 minutes to ensure that the mixture is uniform and dense during the pouring process.

9. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: In S5, the curing method includes one of standard curing, water bath curing and supersaturated calcium hydroxide solution curing, the standard curing temperature is 18-22°C, and the humidity is greater than 95%; the water bath curing temperature is 20-80°C, and the humidity is 100%; the supersaturated calcium hydroxide solution curing temperature is 18-22°C, and the humidity is 100%.

10. The method for preparing a high-performance fiber-reinforced cement-based material according to claim 4, characterized in that: The high-performance fiber-reinforced cement-based material has a compressive strength greater than 30 MPa, and a porosity lower than that of cement-based materials that do not use solid waste incineration bottom ash when the solid waste incineration bottom ash replacement rate is 5-10%. As the solid waste incineration bottom ash replacement rate increases, the physicochemical energy and carbon emissions are lower than those of cement-based materials that do not use solid waste incineration bottom ash, and the solidification efficiency of heavy metal ions in solid waste incineration bottom ash is higher than 98%.

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