Method for preparing alkali efflorescence resistant kerb by using marble saw mud with high chromium content, kerb and application

Abstract

The invention provides a method for preparing an alkali efflorescence resistant curb by using marble saw mud with high chromium content, the curb and application, and belongs to the technical field of building materials. The method comprises the following steps: step 1, obtaining a marble saw mud activated material; 2, adding glucose and quick lime, and uniformly mixing; 3, adding the surfactant, the expanded graphite, the polyvinyl alcohol and the talcum powder, and uniformly mixing; 4, adding the stone-making base material, the reinforcing agent, the water reducing agent and a proper amount of water, and fully and uniformly stirring; and step 5, loading into a stone making mold, carrying out static pressure molding, and then carrying out standard curing for 10-20 days to obtain the alkali efflorescence resistant curb. According to the method provided by the invention, after the marble sawing mud is treated and other components are optimized, the marble sawing mud with a relatively large mixing amount can be more effectively filled, dispersed and combined in a mixture system, the strength, alkali efflorescence resistance and salt freezing resistance of the curb are improved, and the method has very good economic benefits and environmental benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a method for preparing an anti-alkali curbstone by utilizing marble saw mud with a high chromium content. Background Art

[0002] Marble saw mud refers to solid waste such as grinding materials and cutting scraps generated in the marble cutting process. Piling up marble saw mud not only occupies a large area of land, but also easily causes dust and water pollution.

[0003] In the prior art, low-value-added sawdust stone powder with a large proportion of particle size greater than 60 mesh is usually used to prepare building materials such as concrete and cement bricks. However, a large number of waste stone powder raw materials currently have a large problem of exceeding environmental indicators. For example, some marble sawdust was detected to have a water-soluble hexavalent chromium content far exceeding the environmental indicator requirements of concrete (≤200mg / t). If it is directly mixed with cement and sand to make concrete or bricks, it is not only difficult to meet national standards, but also seriously pollutes the environment and affects product performance. In addition, this type of sawdust raw material is difficult to process using conventional reducing agents such as ferrous sulfate and reduction reaction methods, because the reduction reaction of the above-mentioned reducing agent needs to be carried out under acidic conditions, and the marble-derived sawdust stone powder contains at least 60% calcium carbonate. Conventional treatment methods will cause a large loss of stone powder raw materials, and the generated trivalent iron ions are also difficult to remove, making it unsuitable for use in masonry or concrete. At the same time, some studies have shown that when stone powder solid waste containing a large amount of calcium carbonate is mixed with cement and other raw materials to make concrete, due to its low activity and slower hydration reaction than cement, although it can be used as an admixture and cementitious material to increase the density and durability of the product, it has poor bonding with the cement base, which in turn causes the strength of the product to decrease, and can only be used in a smaller dosage.

[0004] The alkali reversion of stone is caused by alkaline substances such as calcium hydroxide in cement, which dissolve in a humid or water-soaked environment, move through the pores to the surface of the stone and precipitate into white powder, which not only affects the appearance, but also causes damage to the internal and edge structures, which has an important impact on the service life of the stone. Curbstones are often located between the dividing strip and the road surface of urban roads, between the sidewalk and the road surface, at the edge of the central dividing strip, on the right side of the lane or on the outer edge of the shoulder, etc. Due to road scouring, rainy and snowy weather, etc., they will repeatedly come into contact with water or be partially immersed in water. Traditional stone or concrete is more likely to have alkali reversion in such an environment. Summary of the invention

[0005] To solve the above problems, the present application aims to provide a method for effectively and largely using marble sawdust containing a high water-soluble hexavalent chromium content, while improving the environmental protection problems of marble sawdust, further enhancing the bonding property with cement-based materials and exerting the filling effect of sawdust to improve the density of the product, and thus having a significantly improved mechanical strength and anti-alkali return ability for the preparation of curbstones.

[0006] On the one hand, the present application provides a method for preparing anti-alkali return curbstones using marble sawdust with a high chromium content, and the method includes: Step 1: Perform vibration screening on the marble sawdust to obtain a screened material, and continue vibrating the screened material for 10 - 60 minutes to obtain an activated marble sawdust material for standby; Step 2: After adding an appropriate amount of water to the activated marble sawdust material and fully stirring, add glucose and quicklime and mix evenly to obtain a first mixture; Step 3: Add a surfactant, expanded graphite, polyvinyl alcohol, and talcum powder to the first mixture and mix evenly to obtain a second mixture; Step 4: Add a stone-making base material, a strengthening agent, a water-reducing agent, and an appropriate amount of water to the second mixture and fully stir evenly to obtain a stone-making mixture; Step 5: Load the stone-making mixture into a stone-making mold, perform static pressure molding, and then carry out standard curing for 10 - 20 days to obtain the anti-alkali return curbstones; Wherein, the water-soluble hexavalent chromium content in the marble sawdust is greater than 200 mg / t; the stone-making base material includes cement, crushed stones, fly ash, and slag powder.

[0007] In one embodiment, the water-soluble hexavalent chromium content in the marble sawdust is 200 - 1000 mg / t, preferably 300 - 800 mg / t, and more preferably 400 - 700 mg / t.

[0008] In one embodiment, the mass percentage content of calcium carbonate in the marble sawdust is ≥60%, preferably 60% - 95%.

[0009] In one embodiment, in Step 1, the vibration screening can be processed using a conventional commercially available vibration screening machine.

[0010] In one embodiment, the particle size of the screened material in Step 1 is 40 - 60 mesh.

[0011] In one embodiment, the vibration frequency of the vibration is 150 - 250 times / min, and the vibration amplitude is 0 - 5 mm.

[0012] It is understandable that the "high chromium content" described in this application refers to the content of highly water-soluble hexavalent chromium. In this application, marble sawdust sludge with a water-soluble hexavalent chromium content higher than the environmental index requirements is used as the raw material. After vibration screening and activation, on the one hand, its particle size is suitable for replacing medium sand as fine aggregate, and on the other hand, it can make the water-soluble hexavalent chromium in the sawdust sludge dissolve better after adding water subsequently. Then, after adding quicklime and excessive glucose, in the alkaline environment and exothermic conditions where quicklime reacts with water to form slaked lime calcium hydroxide, hexavalent chromium can be rapidly reduced by glucose to trivalent chromium, and further form calcium chromate and amphoteric chromium hydroxide. Thus, while solving the environmental protection problem of sawdust sludge, on the one hand, it can reduce the porosity of the final stone mixing material, improve the density and the strength of the final curbstone, and reduce the channels for water to enter the stone interior and the outward migration of internal alkaline substances after the curbstone is soaked in water. On the other hand, when the curbstone is actually applied, it can react with the alkaline substances precipitated inside the stone in the alkali-returning environment, reduce the generation of alkaline substances, which is beneficial to improving the alkali-return resistance of the curbstone. It can also react with chloride ions in salt water to form chromate, play a protective role for the stone aggregate, assist in improving the salt frost resistance of the curbstone, make the curbstone more suitable for rainy and snowy weather and resistant to industrial salt snow melting agents, and extend the service life of the curbstone. At the same time, the calcium gluconate generated by the reduction reaction can also act as a retarder and binder for the mixing material, especially when quicklime reacts with water to release a large amount of heat, the bonding ability is further improved. While extending the setting time and improving the working performance, it assists in enhancing the bonding ability between the sawdust sludge and the hydrate of the stone-making base material, which is beneficial to further exerting the filling property of the sawdust sludge and improving the strength of the curbstone.

[0013] In one embodiment, by mass, the following raw material components are used in the method: 50 - 65 parts of activated marble sawdust sludge, 0.1 - 3 parts of glucose, 1 - 5 parts of quicklime, 0.1 - 1 part of surfactant, 2 - 6 parts of expanded graphite, 0.1 - 1 part of polyvinyl alcohol, 1 - 2 parts of talcum powder, 5 - 20 parts of cement, 70 - 100 parts of crushed stone, 5 - 8 parts of fly ash, 10 - 20 parts of slag powder, 1 - 3 parts of enhancer, 0.1 - 1 part of water reducer, and 6 - 12 parts of water.

[0014] In one embodiment, one-half to two-thirds of the 6 - 12 parts of water is added in step two, and the remaining water is added in step four.

[0015] In one embodiment, the surfactant is sodium maleic anhydride - acrylic acid copolymer, with a molecular weight of 300 - 800, and the monomer molar ratio of maleic acid to acrylic acid is 1:(0.6 - 0.8).

[0016] Among them, sodium maleic anhydride-acrylic acid copolymer has good dispersibility for carbonates when used as a concrete surfactant, can significantly improve the uniformity of the hydrate after mixing sawdust and stone-making aggregates, and does not foam compared with other surfactants, assisting in enhancing the density of the mixture and reducing the porosity. At the same time, the copolymer with a specific molar ratio of maleic acid and acrylic acid monomers also has a certain viscosity, which is beneficial to enhancing the viscosity and improving the bonding effect of sawdust, crushed stone aggregates and cement hydration products.

[0017] In one embodiment, the expansion ratio of the expanded graphite is 250 to 350 times.

[0018] In one embodiment, the particle size of the talcum powder is 400 to 600 mesh.

[0019] Among them, expanded graphite and talcum powder can significantly improve the plasticity of the mixture, which is beneficial to greatly improving the compressive and flexural strengths of the stone. Moreover, their hydrophobicity is also beneficial to reducing the water absorption rate of the stone and reducing the dissolution of alkaline substances in the stone. At the same time, the two also have strong thixotropy, can effectively reduce the pores in the mixture, improve the density and impermeability, reduce the migration of alkaline substances in the stone, and is beneficial to assisting in improving the anti-alkali return ability.

[0020] The thickener and thixotropic agent play an important role in the wrapping and uniformity between the cementitious material and the aggregate in the concrete. In the raw materials of the curbstone of the present application, sodium maleic anhydride-acrylic acid copolymer with a specific monomer ratio, expanded graphite with a specific expansion ratio and talcum powder are compounded together, further improving the overall uniformity and density of the mixture, significantly improving the bonding ability and dispersing ability of sawdust in the mixture system, and being beneficial to improving the strength, durability, anti-alkali return and salt frost resistance of the curbstone.

[0021] In one embodiment, the molecular weight of the polyvinyl alcohol is 20,000 to 90,000.

[0022] Among them, polyvinyl alcohol with a relatively large molecular weight, on the one hand, has good dispersibility for expanded graphite, preventing graphite aggregation from affecting the strength; on the other hand, it can also be used as a coagulant, cooperating with the calcium gluconate retarder generated in the previous step to adjust the setting time after the stone-making is formed.

[0023] In one embodiment, the reinforcing agent is selected from one or more of potassium silicate, sodium silicate, and aluminum silicate.

[0024] Among them, the above-mentioned reinforcing agent can accelerate the cement maturation, accelerate the hardening, significantly improve the early strength of the stone-making mixture, enhance the waterproof and impermeability performance, and can also improve the stability of trivalent chromium in the mixture and inhibit its oxidation.

[0025] In one embodiment, the water reducing agent is an aliphatic superplasticizer.

[0026] In one embodiment, the cement is P·O 42.5 cement.

[0027] In one embodiment, the crushed stone is continuously graded crushed stone with a size of 5 - 20 mm.

[0028] In one embodiment, the fly ash is Class II fly ash.

[0029] In one embodiment, the slag powder is S95 slag powder.

[0030] In one embodiment, the method of uniformly mixing in each step is stirring and mixing. Optionally, a commercially available concrete mixer can be used for stirring. The rotation speed during stirring is 20 - 40 r / min, for example, 35 r / min; the stirring duration for each step is preferably 1 - 10 min.

[0031] In one embodiment, the total stirring duration from Step 2 to Step 4 does not exceed 40 min.

[0032] In one embodiment, the static pressure forming can be operated using existing commercially available curbstone production equipment, such as a fully automatic curbstone hydraulic press.

[0033] In one embodiment, in Step 5, the pressure for static pressure forming is 20 - 25 MPa.

[0034] On the other hand, the present application also provides a curbstone prepared by using the method.

[0035] On the other hand, the present application also provides the application of the curbstone in building engineering, road engineering, municipal engineering or garden engineering.

[0036] The present application has at least the following beneficial effects: The curbstone preparation method provided by the present application uses marble sawdust mainly composed of calcium carbonate and containing a relatively high content of water-soluble hexavalent chromium as raw materials. After vibrating screening and reduction treatment of the sawdust raw materials, not only the content of hexavalent chromium in the raw materials is effectively reduced, improving its environmental properties, but also it is beneficial to reduce the porosity, improve the density of the stone-making admixture, increase the adhesiveness and strength, and effectively improve the anti-alkali return ability and salt freeze resistance of the curbstone; The curbstone preparation method provided by this application, when using marble sawdust as a raw material, also optimizes other components in the stone-making admixture. With the cooperation of components having certain viscosity-increasing and thixotropic properties, a large amount of marble sawdust can be more effectively filled, dispersed, and combined in the mixture system, which is conducive to improving the strength, alkali resistance, and salt freeze resistance of the curbstone. At the same time, it also significantly increases the utilization rate of marble sawdust, having good economic and environmental benefits. Detailed Embodiments

[0037] To more clearly explain the overall concept of this application, the following will be described in detail by way of examples. In the following description, a large number of specific details are given to provide a more thorough understanding of this application. However, it is obvious to those skilled in the art that this application can be implemented without one or more of these details. In other examples, to avoid confusion with this application, some well-known technical features in the art are not described.

[0038] The production processes, experimental methods, or detection methods involved in the embodiments of the present invention are all conventional methods in the prior art without special instructions, and their names and / or abbreviations are all conventional names in the art and are very clear and definite in the relevant application fields. Those skilled in the art can understand the conventional process steps according to the names and apply the corresponding equipment and implement them under conventional conditions or conditions recommended by the manufacturer.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0040] There are no special restrictions on the sources of various instruments, equipment, raw materials, or reagents used in the embodiments of the present invention. Without special instructions, they can all be obtained from conventional commercial channels or prepared according to the conventional methods well-known to those skilled in the art.

[0041] In the following embodiments, marble saw mud is solid waste produced by processing marble in a stone processing plant in Zibo, and its calcium carbonate content is 65% to 85%, and its water-soluble hexavalent chromium content is 300 to 800 mg / t; glucose is commercially available industrial-grade glucose; maleic anhydride acrylic acid copolymer sodium salt is purchased from commercial sources, with a molecular weight of 300 to 800, or can be made by known methods; polyvinyl alcohol is commercially available, model 24-88p, molecular weight 24000 to 88000; cement is commercially available P·O 42.5 cement; slag powder is commercially available S95 slag powder; fly ash is commercially available Class II fly ash; and crushed stone is commercially available 5 to 20 mm continuous graded crushed stone. The remaining raw materials or components are all commercially available conventional building materials.

[0042] In the following embodiments, a common commercially available vibrating screening machine may be used for vibration screening, a common commercially available curbstone hydraulic press may be used for static pressure forming, and a conventional commercially available concrete mixer may be used for mixing and stirring.

[0043] Example 1 This embodiment provides a method for preparing an anti-alkali curbstone using marble saw mud with a high chromium content, and the method specifically comprises the following steps: Step 1: Vibrate and screen the marble saw mud to obtain a sieved material, and continue to vibrate the sieved material for 10 to 60 minutes to obtain a marble saw mud activated material for standby use; Step 2, adding appropriate amount of water to the marble saw mud activation material and stirring thoroughly, then adding glucose and quicklime and mixing evenly to obtain a first mixture; Step 3: adding a surfactant, expanded graphite, polyvinyl alcohol and talc to the first mixture and mixing them evenly to obtain a second mixture; Step 4: Add the stone-making base material, reinforcing agent, water reducing agent and appropriate amount of water to the second mixture and stir well to obtain a stone-making mixture; Step 5: Put the stone-making mixture into the stone-making mold, and carry out standard curing for 10 to 20 days after static pressure molding to obtain the anti-alkali curbstone; Among them, the water-soluble hexavalent chromium content in marble saw mud is 573 mg / t; the stone-making base materials include cement, crushed stone, fly ash and slag powder.

[0044] Among them, in step one of the above method, the marble sawdust sludge is subjected to vibration screening, where the vibration frequency is 220 times / min, the vibration amplitude is 0 - 5 mm, the screened material with a particle size of 40 - 60 mesh is taken, and the screened material is vibrated for another 30 min under the above parameters to obtain the activated marble sawdust sludge for standby. By mass fraction, prepare the following raw material components for preparation: 58 parts of the activated marble sawdust sludge obtained in step one, 1 part of industrial glucose, 1.5 parts of quicklime, 0.5 part of sodium maleic anhydride - acrylic acid copolymer (the monomer molar ratio of maleic acid and acrylic acid is 1:0.7, and the molecular weight is about 617), 5 parts of expanded graphite (the expansion multiple is 250 times), 0.5 part of polyvinyl alcohol, 1 part of talcum powder, 15 parts of cement, 85 parts of crushed stone, 7 parts of fly ash, 15 parts of slag powder, 0.5 part of potassium silicate, 1 part of aluminum silicate, 0.6 part of aliphatic superplasticizer, and 12 parts of water. The mixing method is mixing by stirring, and the stirring speed is 35 r / min.

[0045] In step two of the above method, 7 parts of water are added to the activated marble sawdust sludge, stirred for 1 - 3 min, then industrial glucose and quicklime are added and mixed evenly, and left standing for 1 - 2 min to obtain the first mixture.

[0046] In step three of the above method, sodium maleic anhydride - acrylic acid copolymer, expanded graphite, polyvinyl alcohol, and talcum powder are added to the first mixture obtained in step two and mixed thoroughly to obtain the second mixture.

[0047] In step four of the above method, cement, crushed stone, fly ash, slag powder, potassium silicate, aluminum silicate, and 5 parts of water are added to the second mixture obtained in step three, and stirred evenly to obtain the stone - making mixture.

[0048] In step five of the above method, the stone - making mixture obtained in step four is loaded into the stone - making mold for the curbstone, statically pressed at 22 MPa, and then subjected to standard curing for 15 days, and then it can be taken out of the warehouse.

[0049] Example 2 The preparation method of the curbstone in this example is substantially the same as that in Example 1, except that, by mass fraction, prepare the following raw material components for preparation: 62 parts of the activated marble sawdust sludge (the water - soluble hexavalent chromium content is 465 mg / t), 1.5 parts of industrial glucose, 2 parts of quicklime, 0.8 part of sodium maleic anhydride - acrylic acid copolymer (the monomer molar ratio of maleic acid and acrylic acid is 1:0.7, and the molecular weight is about 617), 5 parts of expanded graphite (the expansion multiple is 300 times), 0.5 part of polyvinyl alcohol, 1 part of talcum powder, 10 parts of cement, 85 parts of crushed stone, 7 parts of fly ash, 15 parts of slag powder, 0.5 part of potassium silicate, 1 part of aluminum silicate, 0.5 part of aliphatic superplasticizer, and 12 parts of water.

[0050] Example 3 The preparation method of the curbstone in this embodiment is substantially the same as that in Embodiment 1, except that, by mass fraction, the following raw material components are prepared for production: 53 parts of activated marble sawdust (water-soluble hexavalent chromium content is 638 mg / t), 1.5 parts of industrial glucose, 2 parts of quicklime, 0.4 part of sodium salt of maleic anhydride-acrylic acid copolymer (molar ratio of maleic acid to acrylic acid monomers is 1:0.7, molecular weight is about 617), 5 parts of expanded graphite (expansion multiple is 350 times), 0.5 part of polyvinyl alcohol, 1 part of talcum powder, 18 parts of cement, 85 parts of crushed stone, 7 parts of fly ash, 15 parts of slag powder, 0.5 part of potassium silicate, 1 part of aluminum silicate, 0.7 part of aliphatic superplasticizer, and 12 parts of water.

[0051] The curbstones prepared in the above Embodiments 1 to 3 are respectively denoted as Sample 1# to 3#. Meanwhile, the raw material components of this application are also optimized. Specifically, in the raw material components of Embodiment 1, the molar ratios of maleic acid to acrylic acid monomers of the sodium salt of maleic anhydride-acrylic acid copolymer are respectively replaced with 1:0.5 (molecular weight is about 559) and 1:1 (molecular weight is about 703), and the obtained curbstone samples are respectively denoted as Sample 4# and Sample 5#; in the raw material components of Embodiment 1, the expansion multiples of the expanded graphite are 200 times and 400 times respectively, and the obtained curbstone samples are respectively denoted as Sample 6# and Sample 7#; in the raw material components of Embodiment 1, selected activated marble sawdust with a water-soluble hexavalent chromium content lower than 200 mg / t (the measured water-soluble hexavalent chromium content is 164 mg / t) is used as the raw material, and 3.5 parts of calcium gluconate are used to replace industrial glucose and quicklime, and the obtained curbstone sample is denoted as Sample 8#.

[0052] Comparative Example 1 A C30 concrete curbstone is used as a comparative example, and its formula is: 30 parts of cement, 70 parts of medium sand (particle size 0.25 - 0.5 mm), 120 parts of crushed stone, and 20 parts of water. The preparation method is mixing and stirring, and the stone-making conditions are the same as those in Step Five of Embodiment 1. The obtained curbstone sample is denoted as D1#.

[0053] For each example in the above embodiments and comparative examples, 4 samples were made respectively. When cured for 10 days, the performance was detected according to the method in the national building materials industry standard "JC / T 899-2016 Concrete Curbstone", and the obtained results were averaged. Among them, the water-soluble hexavalent chromium content of the finished product was detected after static pressure molding; the salt frost resistance was the average mass loss of ND28 salt frost cycles; the detection of efflorescence phenomenon referred to the detection method of efflorescence phenomenon in the national standard "GB / T 2542-2012 Test Methods for Masonry Bricks". Among them, to better fit the weather change scenario during the actual application of the curbstone, the detection method of soaking for 7 days and then drying in the method was changed to soaking for 3 days, drying for 2 hours, then repeating soaking, and cycling 5 times for a total of 15 days, and observing whether there was white powder precipitation on the surface of the sample and whether there was edge damage or shedding at the edge of the brick body.

[0054] The specific detection results are shown in Table 1:

[0055] It can be seen from the results in Table 1 that compared with the curbstone made of traditional C30 fine aggregate concrete, the curbstone prepared by the preparation method of the present application has better flexural strength and compressive strength and lower water absorption rate. The mass loss is significantly reduced under salt frost conditions, no alkaline powder precipitates after 15 days of cyclic soaking, and the edge of the stone is intact without damage, which is suitable for the actual use environment of curbstones in building engineering, road engineering, municipal engineering or garden engineering. At the same time, when using the method provided by the present application to prepare curbstones, a large amount of marble sawdust with high hexavalent chromium content can be utilized, and the hexavalent chromium content in the finished product is significantly reduced, which has great economic and environmental benefits. And the selection of specific components in the system has a certain influence on the various performances of the final curbstone. Among them, the curbstones prepared in Examples 1 to 3 showed more advantageous mechanical strength, salt frost resistance and anti-alkali return ability, and are more preferred examples of the present application.

[0056] The above are only the embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A method for preparing an anti-alkali-returning curbstone using marble sawdust with a high chromium content, characterized in that, The method includes the following steps: Step 1: Perform vibrating screening on the marble sawdust sludge to obtain a screened material, and continue vibrating the screened material for 10 - 60 minutes to obtain an activated marble sawdust sludge material for standby; Step 2: Add an appropriate amount of water to the activated marble sawdust sludge material, stir well, then add glucose and quicklime and mix evenly to obtain a first mixture; Step 3: Add a surfactant, expanded graphite, polyvinyl alcohol, and talcum powder to the first mixture and mix evenly to obtain a second mixture; Step 4: Add a stone-making base material, a strengthening agent, a water-reducing agent, and an appropriate amount of water to the second mixture and stir well to obtain a stone-making mixture; Step 5: Load the stone-making mixture into a stone-making mold, perform static pressure molding, and then carry out standard curing for 10 - 20 days to obtain the anti-alkali return curbstone; Among them, the water-soluble hexavalent chromium content in the marble sawdust sludge is greater than 200 mg / t; the stone-making base material includes cement, crushed stone, fly ash, and slag powder.

2. The method according to claim 1, wherein In Step 1, the particle size of the screened material is 40 - 60 mesh; And / or, the vibration frequency of the vibrating screening is 150 - 250 times / min, and the vibration amplitude is 0 - 5 mm.

3. The method according to claim 2, wherein By mass, the following raw material components are used in the method: 50 - 65 parts of activated marble sawdust sludge material, 0.1 - 3 parts of glucose, 1 - 5 parts of quicklime, 0.1 - 1 part of surfactant, 2 - 6 parts of expanded graphite, 0.1 - 1 part of polyvinyl alcohol, 1 - 2 parts of talcum powder, 5 - 20 parts of cement, 70 - 100 parts of crushed stone, 5 - 8 parts of fly ash, 10 - 20 parts of slag powder, 1 - 3 parts of strengthening agent, 0.1 - 1 part of water-reducing agent, and 6 - 12 parts of water.

4. The method according to claim 3, characterized in that, One-half to two-thirds of the 6 - 12 parts of water is added in Step 2, and the remaining water is added in Step 4.

5. The method according to claim 3, wherein The surfactant is sodium maleic anhydride-acrylic acid copolymer, with a molecular weight of 300 - 800, and the monomer molar ratio of maleic acid to acrylic acid is 1:(0.6 - 0.8); And / or, the expansion multiple of the expanded graphite is 250 - 350 times.

6. The method according to claim 3, wherein The strengthening agent is selected from one or more of potassium silicate, sodium silicate, and aluminum silicate; And / or, the molecular weight of the polyvinyl alcohol is 20000 - 90000; And / or, the water-reducing agent is an aliphatic high-efficiency water-reducing agent.

7. The method according to claim 1, characterized in that The cement is P·O 42.5 cement; And / or, the crushed stone is 5 - 20 mm continuously graded crushed stone; And / or, the fly ash is Class II fly ash; And / or, the slag powder is S95 slag powder.

8. The method according to claim 1, characterized in that, The total stirring duration of Steps 2 to 4 does not exceed 40 minutes; And / or, in Step 5, the pressure of static pressure molding is 20 - 25 MPa.

9. A curbstone prepared by the method according to any one of claims 1 - 8.

10. The application of the curbstone according to claim 9 in building engineering, road engineering, municipal engineering, or garden engineering.

Images