Straw fiber applied to mudstone solid waste improved roadbed filler and preparation method thereof
By combining straw fiber with mudstone-soil mixture, an improved roadbed filler was prepared, which solved the problem of strength reduction of mudstone-soil mixture during freeze-thaw cycles, improved the stability and engineering application value of the roadbed, and reduced environmental pollution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2024-07-24
- Publication Date
- 2026-07-07
Smart Images
Figure CN118771767B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building materials technology, and relates to a roadbed filler material improved from mudstone solid waste using straw fiber and its preparation method. Background Technology
[0002] Due to urban foundation pit excavation and subway tunnel excavation, mudstone and silty clay are mixed and deposited in the strata, forming a unique mudstone-soil mixture. Mudstone particles soften upon contact with water, leading to a significant decrease in strength and an increase in deformation. Furthermore, in seasonally frozen regions, when this mudstone-soil mixture is used as roadbed fill, the frequent freezing and thawing cycles cause significant moisture migration, altering the moisture distribution and pore structure of the roadbed fill. This results in a severe decrease in the roadbed's bearing capacity, causing serious settlement and deformation, posing a serious threat to road safety. This makes it unsuitable for engineering construction. Simultaneously, major crops such as corn produce large amounts of straw along with grain. Returning the straw to the field makes the soil too loose, affecting the planting of the next crop. Burning the straw causes serious environmental pollution. Summary of the Invention
[0003] To achieve the above objectives, this invention provides a roadbed filler material improved from mudstone solid waste using straw fiber and its preparation method, which solves the problem of resource utilization of construction solid waste such as mudstone-mixed soil with poor stability and low engineering application value, and significantly improves the ability of mudstone-mixed soil roadbed to resist freeze-thaw cycle effects.
[0004] The technical solution adopted in this invention is a roadbed filler material improved by applying straw fiber to mudstone solid waste, comprising the following raw materials: mudstone mixed soil, corn straw, purified water and water-repellent agent.
[0005] Further, by mass fraction, the mixture comprises 92-97 parts mudstone-soil mixture, 3-8 parts corn stalks, 15-20 parts purified water, and 20-25 parts water-repellent agent.
[0006] Furthermore, the hydrophobic agent is polysiloxane powder.
[0007] This invention also provides a method for preparing roadbed filler material modified from mudstone solid waste using straw fiber, comprising the following steps:
[0008] Step S1: Weigh out 92-97 parts of mudstone-soil mixture, 3-8 parts of corn stalks, 15-20 parts of purified water, and 20-25 parts of water-repellent agent according to the following mass proportions;
[0009] Step S2: Grind the mudstone mixture from step S1 into uniform particles;
[0010] Step S3: Separate the corn stalks from the pith in step S1, peel off the pith remaining in the stalk skin, and keep the stalk skin dry and clean;
[0011] Step S4: Pre-process the corn stalk skin separated in step S3 by cutting;
[0012] Step S5: Use a crusher to initially crush the corn stalk peel after the pretreatment in step S4, and then perform fine crushing to obtain ultrafine straw fiber; soak the crushed ultrafine straw fiber in a water-repellent agent solution and stir at a constant temperature to obtain the finished straw fiber.
[0013] Step S6: Heat and dry the mudstone mixture prepared in S2 and the finished straw fiber prepared in S5 to constant weight, then remove them and let them stand at room temperature.
[0014] Step S7: Mix the mudstone-rock mixture from step S6 with the finished straw fiber to prepare straw fiber-modified mudstone-rock mixture; wherein, the straw fiber content is 3%~8%, and the straw fiber content refers to: the mass fraction of straw / (the mass fraction of mudstone-rock mixture + the mass fraction of straw).
[0015] Step S8: Spray the purified water onto the straw fiber-modified mudstone mixture in batches multiple times, spraying until the surface of the mixture is moist each time, and then mechanically stir it until the purified water is completely added to the straw fiber-modified mudstone mixture. Then place it in an opaque, airtight bag and seal it to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0016] Furthermore, in step S2, the particle size is less than 2 mm.
[0017] Furthermore, during the pre-processing of cutting in step S4, the length of the bark is controlled to be 5~8cm and the width is controlled to be 2~4cm.
[0018] Furthermore, in step S5, the straw fibers that have been initially crushed are further crushed after passing through a 2-5 mm sieve; the straw fibers are then soaked in a water-repellent agent solution and stirred at a constant temperature for 1-2 hours.
[0019] Furthermore, the heating and drying temperature in step S6 is 100~108℃.
[0020] Furthermore, in step S7, a mixer is used to uniformly mix the mixture at a speed of 400-500 rpm.
[0021] Furthermore, in step S8, the sealing time is 10~12 hours.
[0022] The beneficial effects of this invention are:
[0023] 1. Dynamic resilient modulus tests were conducted on mudstone-soil mixtures under different moisture contents, freeze-thaw cycles, and straw fiber content. The effects of moisture and freeze-thaw cycles on the mechanical properties of mudstone-soil mixtures were quantitatively characterized. The strength loss was as high as 86.7% at saturation and 76.7% after 7 freeze-thaw cycles. The mechanical properties of the mudstone-soil mixtures were improved. Under the optimal content, the strength increased by 189.7% after 7 freeze-thaw cycles, significantly improving the strength of the mudstone-soil mixtures. The optimal straw fiber content was determined, providing a technical basis for the design and construction technology of composite subgrade structures.
[0024] 2. By improving the mudstone-soil mixture, the stability and engineering application value of the mudstone-soil mixture are enhanced; at the same time, construction waste is effectively utilized, reducing environmental pollution to the city and saving road construction resources. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 The figures shown are the test results of dynamic resilient modulus of mudstone-rock mixture without straw fiber in the embodiments of the present invention; wherein, (a) is a numerical figure of dynamic resilient modulus under different moisture contents, and (b) is a numerical figure of dynamic resilient modulus under different freeze-thaw cycles.
[0027] Figure 2 This is a graph showing the test results of the dynamic resilient modulus of roadbed filler under different straw fiber content in the experimental examples of this invention.
[0028] Figure 3 This is a numerical diagram of the dynamic resilience modulus of roadbed filler under different straw fiber content and different freeze-thaw cycles in the experimental examples of this invention. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0030] This invention provides a roadbed filler material improved from mudstone solid waste using straw fiber, comprising mudstone-mixed soil, corn straw, purified water, and a water-repellent agent. The components, by weight, are: 92-97 parts mudstone-mixed soil, 3-8 parts corn straw, 15-20 parts purified water, and 20-25 parts water-repellent agent.
[0031] Straw fibers have a rough surface with many tiny grooves. When buried in mudstone-soil mixtures, soil particles are embedded in these grooves, creating strong interaction forces (cohesion and friction at the fiber-soil interface). When subjected to external forces, these forces generate strong frictional resistance to limit soil displacement and deformation, effectively improving the soil's tensile and shear strength, bearing capacity, and dynamic resilient modulus.
[0032] The hydrophobic agent is polysiloxane powder.
[0033] This invention also provides a method for preparing roadbed filler material modified from mudstone solid waste using straw fiber, comprising the following steps:
[0034] 1. Weigh out 92-97 parts by weight of mudstone mixture, 3-8 parts by weight of corn stalks, 15-20 parts by weight of purified water, and 20-25 parts by weight of water-repellent agent, which is polysiloxane powder.
[0035] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0036] 3. Separate the corn stalks from the pith in step S1, peel off the pith remaining in the stalk skin, and keep the stalk skin dry and clean.
[0037] Fourth, pre-process the corn stalk skin separated in step three by cutting it, controlling the length of the skin to be 5-8cm and the width to be 2-4cm.
[0038] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 2-5mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent solution, stir at a constant temperature for 1-2 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0039] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 100~108℃, heat and dry to constant weight, then remove and let stand at room temperature.
[0040] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at a speed of 400-500 rpm to prepare straw fiber modified mudstone mixture.
[0041] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches, each time until the surface of the mixture is moist, and then mechanically mix it.
[0042] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture. Then place it in an opaque, sealed bag and seal it for 10-12 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0043] Example 1:
[0044] 1. Weigh out 95 parts by weight of mudstone mixture, 5 parts by weight of corn stalks, 18 parts by weight of purified water, and 22 parts by weight of water-repellent agent;
[0045] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0046] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0047] Fourth, cut the corn stalk skin obtained in step three into pieces that are 6cm long and 3cm wide.
[0048] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 3mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 1.5 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0049] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 105°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0050] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 450 rpm to prepare a modified mudstone mixture with 5% straw fiber content.
[0051] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0052] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 11 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0053] It should be noted that the straw fiber content mentioned in this invention refers to the mass fraction of straw / (mass fraction of mudstone-soil mixture + mass fraction of straw).
[0054] Example 2:
[0055] 1. Weigh out 97 parts by weight of mudstone mixture, 3 parts by weight of corn stalks, 15 parts by weight of purified water, and 20 parts by weight of water-repellent agent;
[0056] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0057] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0058] Fourth, cut the corn stalk skin obtained in step three into pieces that are 5cm long and 2cm wide.
[0059] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 2mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 1 hour, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0060] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 100°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0061] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at a speed of 400 rpm to prepare a modified mudstone mixture with 3% straw fiber content.
[0062] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0063] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 10 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0064] Example 3:
[0065] 1. Weigh out 92 parts by weight of mudstone mixture, 8 parts by weight of corn stalks, 20 parts by weight of purified water, and 25 parts by weight of water-repellent agent;
[0066] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0067] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0068] Fourth, cut the corn stalk skin obtained in step three into pieces that are 8cm long and 4cm wide.
[0069] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 5mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 2 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0070] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 108°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0071] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 500 rpm to prepare an improved mudstone mixture with 8% straw fiber content.
[0072] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0073] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 12 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0074] Example 4:
[0075] 1. Weigh out 96 parts by weight of mudstone mixture, 4 parts by weight of corn stalks, 18 parts by weight of purified water, and 22 parts by weight of water-repellent agent;
[0076] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0077] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0078] Fourth, cut the corn stalk skin obtained in step three into pieces that are 6cm long and 2cm wide.
[0079] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 4mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent solution, stir at a constant temperature for 1.5 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0080] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 103°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0081] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at a speed of 480 rpm to prepare an improved mudstone mixture with 4% straw fiber content.
[0082] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0083] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 10 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0084] Example 5:
[0085] 1. Weigh out 93 parts by weight of mudstone mixture, 7 parts by weight of corn stalks, 15 parts by weight of purified water, and 20 parts by weight of water-repellent agent;
[0086] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0087] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0088] Fourth, cut the corn stalk skin obtained in step three into pieces that are 5cm long and 2cm wide.
[0089] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 5mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 2 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0090] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 108°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0091] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 500 rpm to prepare a modified mudstone mixture with 7% straw fiber content.
[0092] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0093] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 10 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0094] Example 6:
[0095] 1. Weigh out 94 parts by weight of mudstone mixture, 6 parts by weight of corn stalks, 15 parts by weight of purified water, and 20 parts by weight of water-repellent agent;
[0096] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0097] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0098] Fourth, cut the corn stalk skin obtained in step three into pieces that are 5cm long and 2cm wide.
[0099] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 5mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 2 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0100] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 108°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0101] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 500 rpm to prepare a modified mudstone mixture with 6% straw fiber content.
[0102] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0103] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 12 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0104] Comparative Example 1:
[0105] 1. Weigh out 100 parts of mudstone mixture and 18 parts of purified water by weight.
[0106] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0107] 3. Place the mudstone-soil mixture particles prepared in step 2 into a constant temperature blower box, control the temperature at 105°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0108] 4. Spray the purified water from step 1 onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0109] 5. Repeat step 4 until all the pure water is added to the mudstone mixture, then place it in an opaque, sealed bag and seal it for 11 hours to prepare the roadbed filler.
[0110] Comparative Example 2
[0111] 1. Weigh out 90 parts by weight of mudstone mixture, 10 parts by weight of corn stalks, 18 parts by weight of purified water, and 22 parts by weight of water-repellent agent;
[0112] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0113] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0114] Fourth, cut the corn stalk skin obtained in step three into pieces that are 6cm long and 3cm wide.
[0115] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 3mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 1.5 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0116] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 105°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0117] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 450 rpm to prepare an improved mudstone mixture with 10% straw fiber content.
[0118] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0119] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 11 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0120] Comparative Example 3
[0121] 1. Weigh out 99 parts by weight of mudstone mixture, 1 part by weight of corn stalks, 15 parts by weight of purified water, and 20 parts by weight of water-repellent agent;
[0122] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0123] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0124] Fourth, cut the corn stalk skin obtained in step three into pieces that are 6cm long and 3cm wide.
[0125] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 3mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 1.5 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0126] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 105°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0127] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 450 rpm to prepare a modified mudstone mixture with 1% straw fiber content.
[0128] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0129] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 11 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0130] Comparative Example 4
[0131] 1. Weigh out 89 parts by weight of mudstone mixture, 11 parts by weight of corn stalks, 15 parts by weight of purified water, and 20 parts by weight of water-repellent agent;
[0132] 2. Grind the mudstone mixture from step 1 into uniform particles with a particle size of less than 2mm.
[0133] 3. Separate the corn stalks from the pith in step one, sieve out moldy or poor-quality stalks, peel off the remaining pith from the stalks, and keep the stalks dry and clean.
[0134] Fourth, cut the corn stalk skin obtained in step three into pieces that are 6cm long and 3cm wide.
[0135] 5. Use a crusher to pre-crush the corn stalks after the pretreatment in step 4, and control the crushed straw fibers to pass through a 3mm sieve; then carry out fine crushing to obtain ultrafine straw fibers; soak the crushed straw fibers in a water-repellent agent solution, stir at a constant temperature for 1.5 hours, and carry out anti-corrosion and moisture-proof treatment to obtain the finished straw fibers.
[0136] 6. Place the mudstone-soil mixture particles and straw fibers prepared in steps 2 and 5 into a constant temperature blower box, control the temperature at 105°C, heat and dry to constant weight, then remove and let stand at room temperature.
[0137] 7. Mix the mudstone mixture and straw fiber evenly in step 6 using a mixer at 450 rpm to prepare an improved mudstone mixture with 11% straw fiber content.
[0138] 8. Spray the purified water from step one onto the straw fiber-modified mudstone mixture in batches and multiple times using a spray bottle, spraying until the surface of the mixture is moist each time, and then mechanically mix it.
[0139] 9. Repeat step 7 until all the pure water is added to the straw fiber-modified mudstone mixture, then place it in an opaque, sealed bag and seal it for 11 hours to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
[0140] Experimental Example:
[0141] I. Weigh a total of six portions of subgrade fillers prepared in Examples 1 - 3 and Comparative Examples 1 - 3 (i.e., straw fiber dosages of 0%, 1%, 3%, 5%, 8%, and 10%). Pour them into a cast iron mold with a diameter of 100 mm and a height of 200 mm, and compact them in 5 layers. Perform roughening treatment between layers to improve the interfacial contact condition. After compaction, demold to prepare test specimens.
[0142] II. Use a triaxial saturator to saturate the specimens. First, wrap a thin layer of plastic wrap around the specimen to prevent excessive suction between the specimen and the three - valve membrane after saturation, and to avoid damage to the specimen during demolding. Then, place a filter paper on the permeable stone of the saturator, place the specimen on the filter paper, place the three - valve membranes on the sides of the specimen in sequence, slide the hoop down along the three - valve membranes to fix the three - valve membranes. Subsequently, place a filter paper and a permeable stone on the top of the specimen, fix the triaxial and the upper cover of the saturator to complete the installation of the saturator. Place the saturator in a saturation bucket, turn on the vacuum pump to evacuate the saturation bucket for 3 h, and soak the specimen in water for 10 h to complete the saturation of the specimen.
[0143] III. According to the local measured meteorological data, determine that the lowest temperature of the subgrade in winter is - 10°C, which is also the freezing temperature, and the melting temperature is controlled at the laboratory room temperature, about 23°C. The freezing method is three - dimensional freezing, and the temperature can be controlled at - 10 ± 0.2°C by a temperature - controlled refrigerator. The melting method is to place it in a constant - temperature water bath, and the temperature can be controlled at 23 ± 2°C. To ensure that the temperatures at all points inside the specimen reach the required values during freezing and melting, prepare a specimen with a diameter of 100 mm and a height of 200 mm for temperature calibration. Insert temperature sensors at 0 mm, 25 mm, and 50 mm radially at a height of 100 mm of the specimen, and complete a freeze - thaw cycle with a duration of 24 h within the set temperature.
[0144] IV. According to the required number of freeze - thaw cycles (0, 1, 3, 5, 7), conduct the corresponding number of freeze - thaw cycle tests on the specimens prepared in Step II according to Step III.
[0145] V. The subgrade soil conducts a dynamic resilience modulus test with a UTM - 100 tester, and the test is carried out according to the test procedure specified in the "Regulations". Turn on the computer and the acquisition box supporting the TUTM - 100, place the specimen at the bottom of the triaxial chamber. After proper installation, place the triaxial chamber in the triaxial room, and connect the displacement sensor and the pressure sensor. Open the control program of the computer, input the parameters of the specimen, and adjust the position of the main axis of the loading frame to the center. Open the air valve to provide confining pressure for the specimen. Finally, click "Start Test" and wait for the test to end.
[0146] The dynamic resilient modulus test results of mudstone-rock mixture without straw fiber are as follows: Figure 1 As shown in (a) and (b), the moisture content and the number of freeze-thaw cycles have a significant impact on mudstone-soil mixtures. Under saturated conditions, the strength decreases by as much as 86.7% ((145.9-19.4) / 145.9), and after 7 freeze-thaw cycles, the strength decreases by as much as 76.7% ((145.9-34) / 145.9). Under these conditions, mudstone-soil mixtures do not have engineering value as roadbed fillers.
[0147] The dynamic resilient modulus test results of roadbed fill materials with straw fiber added at concentrations of 0%, 1%, 3%, 5%, 8%, and 10% for improved mudstone-mixed soil are as follows: Figure 2 As shown.
[0148] Depend on Figure 2 It can be seen that, without freeze-thaw cycles, the mudstone-soil mixture with a 5% admixture content exhibits the highest dynamic resilient modulus strength. From... Figure 3 It can be seen that the mudstone-soil mixture with 5% straw fiber content consistently exhibits the highest strength under different freeze-thaw cycles. After seven freeze-thaw cycles with 5% straw fiber content, the improved mudstone-soil mixture still maintains a relatively high strength of 98.5 MPa. Using the dynamic resilience modulus after seven freeze-thaw cycles with 0% straw fiber content as a control, the values after seven freeze-thaw cycles with 1%, 3%, 5%, 8%, and 10% straw fiber content increased by 32.3%, 124.7%, 189.7%, 92.6%, and -12.6%, respectively.
[0149] It is evident that the addition of straw fiber effectively improves the mechanical properties of mudstone-soil mixtures, as the straw fiber acts as a reinforcing and moisture-absorbing agent. At a dosage range of 3-8%, the mudstone-soil mixture exhibits good resistance to freeze-thaw damage; however, at dosages outside this range, the resistance to freeze-thaw damage decreases, and may even show a negative increase. This is because, on the one hand, excessive straw fiber can no longer effectively adsorb soil particles; on the other hand, the interface formed by excessive straw fiber and soil particles provides a channel for moisture migration, leading to an exacerbated frost heave effect.
[0150] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.
Claims
1. A roadbed filler material using straw fiber-modified mudstone solid waste, characterized in that, The raw materials include: mudstone mixture, corn stalks, purified water, and a water-repellent agent, wherein the water-repellent agent is polysiloxane powder; The roadbed filler is prepared according to the following steps, comprising 92-97 parts by weight of the mudstone-soil mixture, 3-8 parts by weight of the corn stalks, 15-20 parts by weight of the purified water, and 20-25 parts by weight of the water-repellent agent: Step S1: Weigh out 92-97 parts of mudstone-soil mixture, 3-8 parts of corn stalks, 15-20 parts of purified water, and 20-25 parts of water-repellent agent according to the following mass proportions; Step S2: Grind the mudstone mixture from step S1 into uniform particles; Step S3: Separate the corn stalks from the pith in step S1, peel off the remaining pith from the stalk skin, and keep the stalk skin dry and clean; Step S4: Pre-process the corn stalk skin separated in step S3 by cutting; Step S5: Use a crusher to initially crush the corn stalk peel after the pretreatment in step S4, and then perform fine crushing to obtain ultrafine straw fiber; soak the crushed ultrafine straw fiber in a water-repellent agent solution and stir at a constant temperature to obtain the finished straw fiber. Step S6: Heat and dry the mudstone mixture prepared in S2 and the finished straw fiber prepared in S5 to constant weight, then remove them and let them stand at room temperature. Step S7: Mix the mudstone-rock mixture from step S6 with the finished straw fiber to prepare straw fiber-modified mudstone-rock mixture; wherein, the straw fiber content is 3%~8%, and the straw fiber content refers to: the mass fraction of straw / (the mass fraction of mudstone-rock mixture + the mass fraction of straw). Step S8: Spray the purified water onto the straw fiber-modified mudstone mixture in batches multiple times, spraying until the surface of the mixture is moist each time, and then mechanically stir it until the purified water is completely added to the straw fiber-modified mudstone mixture. Then place it in an opaque, airtight bag and seal it to prepare a roadbed filler material modified with straw fiber mudstone solid waste.
2. The roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, In step S2, the particle size is less than 2 mm.
3. The roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, In step S4, during the pre-processing of cutting, the length of the bark is controlled to be 5-8cm and the width is controlled to be 2-4cm.
4. The roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, In step S5, the straw fibers that have been initially crushed are passed through a 2-5 mm sieve and then further crushed; the straw fibers are soaked in a water-repellent solution and then stirred at a constant temperature for 1-2 hours.
5. A roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, The heating and drying temperature in step S6 is 100~108℃.
6. A roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, In step S7, a mixer is used to mix the materials evenly at a speed of 400-500 rpm.
7. A roadbed filler material using straw fiber-modified mudstone solid waste as described in claim 1, characterized in that, In step S8, the sealing time is 10~12 hours.