CN115124286B - Environment-friendly regenerated backfill and preparation method thereof - Google Patents
Environment-friendly regenerated backfill and preparation method thereof Download PDFInfo
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- CN115124286B CN115124286B CN202210710323.4A CN202210710323A CN115124286B CN 115124286 B CN115124286 B CN 115124286B CN 202210710323 A CN202210710323 A CN 202210710323A CN 115124286 B CN115124286 B CN 115124286B
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- 238000002360 preparation method Methods 0.000 title abstract description 11
- 239000000463 material Substances 0.000 claims abstract description 86
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 58
- 239000000654 additive Substances 0.000 claims abstract description 57
- 229920001661 Chitosan Polymers 0.000 claims abstract description 55
- 230000000996 additive effect Effects 0.000 claims abstract description 55
- 239000011159 matrix material Substances 0.000 claims abstract description 49
- 238000000034 method Methods 0.000 claims abstract description 46
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000011777 magnesium Substances 0.000 claims abstract description 44
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 44
- 239000002893 slag Substances 0.000 claims abstract description 40
- 238000010276 construction Methods 0.000 claims abstract description 37
- 230000008569 process Effects 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000002699 waste material Substances 0.000 claims abstract description 34
- 239000000203 mixture Substances 0.000 claims abstract description 33
- 239000004568 cement Substances 0.000 claims abstract description 30
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 29
- 238000003756 stirring Methods 0.000 claims abstract description 27
- 239000004115 Sodium Silicate Substances 0.000 claims abstract description 26
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims abstract description 26
- 229910052911 sodium silicate Inorganic materials 0.000 claims abstract description 26
- 229910021487 silica fume Inorganic materials 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 19
- 239000002440 industrial waste Substances 0.000 claims abstract description 18
- 239000002245 particle Substances 0.000 claims abstract description 17
- 239000004927 clay Substances 0.000 claims abstract description 15
- 238000012423 maintenance Methods 0.000 claims abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 7
- 238000011049 filling Methods 0.000 claims abstract description 7
- 239000002689 soil Substances 0.000 claims description 36
- 239000000945 filler Substances 0.000 claims description 29
- 239000005416 organic matter Substances 0.000 claims description 12
- 239000007888 film coating Substances 0.000 claims description 10
- 238000009501 film coating Methods 0.000 claims description 10
- 238000005266 casting Methods 0.000 claims description 7
- 230000006196 deacetylation Effects 0.000 claims description 6
- 238000003381 deacetylation reaction Methods 0.000 claims description 6
- 239000002910 solid waste Substances 0.000 claims description 6
- 238000005086 pumping Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims 1
- 238000003723 Smelting Methods 0.000 abstract description 4
- 239000010813 municipal solid waste Substances 0.000 abstract description 4
- 238000004064 recycling Methods 0.000 abstract description 4
- 239000002131 composite material Substances 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 229910052918 calcium silicate Inorganic materials 0.000 description 18
- 235000012241 calcium silicate Nutrition 0.000 description 18
- 230000000694 effects Effects 0.000 description 16
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 15
- 229910001424 calcium ion Inorganic materials 0.000 description 15
- 238000006703 hydration reaction Methods 0.000 description 15
- 239000000378 calcium silicate Substances 0.000 description 11
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 11
- 229910001385 heavy metal Inorganic materials 0.000 description 11
- 239000000377 silicon dioxide Substances 0.000 description 10
- 230000001105 regulatory effect Effects 0.000 description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 8
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 230000036571 hydration Effects 0.000 description 7
- 230000001276 controlling effect Effects 0.000 description 5
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000005056 compaction Methods 0.000 description 3
- BCAARMUWIRURQS-UHFFFAOYSA-N dicalcium;oxocalcium;silicate Chemical compound [Ca+2].[Ca+2].[Ca]=O.[O-][Si]([O-])([O-])[O-] BCAARMUWIRURQS-UHFFFAOYSA-N 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 238000012876 topography Methods 0.000 description 3
- 229910021534 tricalcium silicate Inorganic materials 0.000 description 3
- 235000019976 tricalcium silicate Nutrition 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000004567 concrete Substances 0.000 description 2
- 230000007123 defense Effects 0.000 description 2
- 239000011381 foam concrete Substances 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000004005 microsphere Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B12/00—Cements not provided for in groups C04B7/00 - C04B11/00
- C04B12/04—Alkali metal or ammonium silicate cements ; Alkyl silicate cements; Silica sol cements; Soluble silicate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/04—Silica-rich materials; Silicates
- C04B14/10—Clay
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/141—Slags
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/146—Silica fume
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/08—Acids or salts thereof
- C04B22/10—Acids or salts thereof containing carbon in the anion
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/38—Polysaccharides or derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00017—Aspects relating to the protection of the environment
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00724—Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention discloses an environment-friendly regenerated backfill, which comprises a matrix and an additive, wherein the matrix consists of clay, construction waste fine aggregate with the particle size smaller than 5mm and water, and the additive consists of sodium carbonate, sodium silicate, magnesium slag from magnesium smelting by a silicothermic process, cement, industrial waste silica fume above 75 and chitosan; the invention also discloses a preparation method of the composite material, which comprises the following steps: 1. uniformly mixing magnesium slag, cement, clay and building rubbish fine aggregate with the grain diameter of less than 5mm after natural air cooling by a silicothermic process; 2. uniformly mixing sodium carbonate, sodium silicate, more than 75 industrial waste silica fume and chitosan, and uniformly stirring the two mixtures; 3. adding water to obtain wet materials; 4. and (5) mold filling and maintenance. The invention adjusts the fluidity, the setting time and the strength of the regenerated backfill material by controlling the composition and the content of the matrix, improves the strength and the density of the regenerated backfill material by controlling the composition and the content of the additive, avoids volume shrinkage and realizes the recycling of resources; the preparation method is simple and convenient and quick in construction.
Description
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to an environment-friendly regenerated backfill and a preparation method thereof.
Background
The backfill for the building is a backfill material for the scenes of foundation pit fertilizer groove backfill, mineral goaf backfill, civil air defense engineering backfill and the like, and the traditional backfill material comprises building ready mixed mortar, gray soil layered backfill, foam concrete and the like. On one hand, the upper layers of the mineral goaf and the civil air defense engineering are capped, the ready mixed mortar has certain contractility, is not easy to fill, has narrow interior and difficult manual operation, is not beneficial to machine ramming construction of gray soil layered backfilling, and needs backfilling with strong fluidity, the curing time being adjustable with working conditions and the strength being adjustable with requirements in consideration of later development work; on the other hand, building foundation pit depth is deepened constantly, the foundation pit is fat narrow and deep in groove, it is bulky, the layer backfill is difficult to tamp in the fat inslot, and backfill such as grit and concrete that the dead weight is great causes the pressure to the foundation pit easily and leads to engineering accident, consequently, need the dead weight little, novel backfill that intensity is high and the shrinkage ratio is low, and its workability (mobility and setting time) can be adjusted along with the operating mode, traditional foam concrete backfill is light and adjustable workability although the dead weight is light, but its cost is high and form the communicating hole easily between the cell, can not be applied to the application scenario that has the requirement to the impermeability.
Because the viscous loess has certain collapsibility, the lightweight low-strength concrete backfill material taking the loess as a main component has volume shrinkage, and adverse effects on pouring of an underground space, such as insufficient pouring phenomenon or volume shrinkage after water spraying, are caused, so that the backfill effect is poor. In addition, the backfill area has various topography and topography, and the backfill with different coagulation property and fluidity is often needed in the construction process along with the change of working conditions, which puts forward higher requirements on the performance of the backfill.
At present, the building rubbish is huge in storage quantity, and the building rubbish aggregate with the diameter of less than 5mm cannot meet the mud content requirement of the building aggregate due to high powder clay content, so that the building rubbish aggregate cannot be directly used. In areas where powdered clay such as loess is used as backfill, construction waste is directly used, but repeated compaction is often required by using equipment, so that the cost is increased, the density is too high after compaction, and foundation settlement is easily caused.
Meanwhile, with the expansion of the metal magnesium industry in China, the yield of magnesium slag produced by smelting magnesium by a silicothermic process is increased year by year, and certain harm is caused to the environment and human health, so that the recycling of the magnesium slag is urgent. Therefore, the application of the silicon thermal smelting magnesium slag in the backfilling field is developed, and the problem of mass accumulation of the magnesium slag can be effectively relieved.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an environment-friendly regenerated backfill material aiming at the defects of the prior art. The environment-friendly regenerated backfill material has the advantages that the fluidity, the setting time and the strength of the regenerated backfill material are effectively regulated by controlling the composition and the content of the matrix, the dead weight is small, the foundation pressure is small, sedimentation is avoided, the setting time can be regulated according to working conditions, the strength is regulated according to actual demands, the strength and the content of the additive are improved by controlling the composition and the content of the additive, the strength and the density of the regenerated backfill material are improved, the volume shrinkage is avoided, the backfill effect is improved, and the recycling of the resources of construction site waste soil and construction waste is realized.
In order to solve the technical problems, the invention adopts the following technical scheme: the environment-friendly regenerated backfill is characterized by comprising a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 1-20%, and the matrix consists of the following components in parts by mass: 10-90 parts of cohesive soil, 10-90 parts of construction waste fine aggregate with the grain diameter smaller than 5mm and 20-40 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: 1 to 5 percent of sodium carbonate, 0 to 5 percent of sodium silicate, 42 to 75 percent of magnesium slag produced by a silicothermic process, 25 to 50 percent of cement, 0 to 7.5 percent of industrial waste silica fume above 75 percent and 0.01 to 0.5 percent of chitosan.
The environment-friendly recycled backfill comprises a matrix and an additive, wherein the cohesive soil and the construction waste fine aggregate are adopted as main components of the matrix, the fluidity and the density of the matrix are effectively regulated by regulating the component content of the cohesive soil and the construction waste fine aggregate, so that the setting time and the strength of the recycled backfill are regulated, meanwhile, the construction waste fine aggregate with the particle size smaller than 5mm contains more powdery clay to play a better binding role, the matrix prepared from the construction waste fine aggregate with the small particle size has lighter weight and smaller dead weight, and the prepared recycled backfill has small pressure on a foundation, so that engineering accidents caused by sedimentation are avoided; after chitosan in the additive is dissolved, the chitosan and calcium ions of dicalcium silicate and calcium oxide in magnesium slag are subjected to complexation reaction by a silicothermic process, so that the dissolution of the calcium ions is promoted, the dissolved calcium ions react with carbonate ions in sodium carbonate to generate calcium carbonate and sodium hydroxide, the generation of the calcium carbonate improves the strength and compactness of backfill, microcrack generation is reduced, volume shrinkage is avoided, the dimensional stability of the backfill is ensured, the backfill effect is further improved, meanwhile, the generated sodium hydroxide is beneficial to the dissolution of the calcium ions in dicalcium silicate with lower hydration activity, and sodium ions contained in cohesive soil in a matrix are also beneficial to the improvement of the dicalcium silicate and tricalcium silicate in cement, so that positive feedback effect is formed, and the backfill effect is further improved; meanwhile, the component sodium silicate in the additive reacts with dissolved calcium ions to generate silicon dioxide, sodium silicate and sodium hydroxide, the silicon dioxide reacts with the dissolved calcium ions to generate hydraulic hydrated calcium silicate, and the sodium hydroxide can activate hydration activities of dicalcium silicate in magnesium slag and tricalcium silicate in cement, so that hydration reaction is promoted, the setting time of the regenerated backfill is shortened rapidly, and the early strength of the regenerated backfill is improved. In addition, the silica micropowder in the industrial waste silica fume of more than 75 has high surface activity, is easy to be adsorbed with chitosan molecules and forms a coated chitosan film, and the lone pair electron pair of N and O of the chitosan molecules on the film adsorbs calcium ions, so that the calcium ions are promoted to react with the silica micropowder to form hydrated calcium silicate with hydraulic property, and the calcium ions are promoted to react with the generated silica to generate the hydrated calcium silicate, so that the strength of the regenerated backfill is improved; because the chitosan has large molecular weight and contains hydrogen bonds, chain folding is formed on the surfaces of silicon dioxide and aluminum oxide in the silicon dioxide micro powder and the cohesive soil, so that the generated hydrated calcium silicate is coated on the surface of the silicon dioxide micro powder to form microspheres, and the reinforcing effect is exerted, so that the strength of the regenerated backfill is further improved, and the backfill effect is improved.
The above 75 industrial waste silica fume in the invention refers to SiO 2 Industrial waste silica fume with the mass content of more than 75 percent.
The environment-friendly regenerated backfill is characterized in that the addition mass percentage of the additive in the matrix is 20%, and the matrix consists of the following components in parts by mass: 90 parts of clay, 10 parts of construction waste fine aggregate with the particle size smaller than 5mm and 30 parts of water, wherein the additive comprises the following components in percentage by mass: 5% of sodium carbonate, 3% of sodium silicate, 42.245% of magnesium slag produced by silicothermic process, 42.245% of cement, 7.5% of industrial waste silica fume above 75% and 0.01% of chitosan. The regenerated backfill material with the preferable composition correspondingly reduces the contents of magnesium slag and chitosan produced by the silicothermic process in the additive by increasing the content of cohesive soil in the matrix, and improves the contents of sodium carbonate, sodium silicate, cement and industrial waste silica fume above 75 percent in the additive, thereby shortening the solidification time of the regenerated backfill material, improving the solidification strength and density of the regenerated backfill material and obtaining the regenerated backfill material with quick solidification, high strength, light weight and low shrinkage.
The environment-friendly regenerated backfill is characterized in that the addition percentage by mass of the additive in the matrix is 10%, and the matrix consists of the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the particle size smaller than 5mm and 30 parts of water, wherein the additive comprises the following components in percentage by mass: sodium carbonate 1%, magnesium slag 74.2125% by silicothermic process, cement 24.7375% and chitosan 0.5%. The recycled filler with the preferable composition improves the content of the construction waste fine aggregate with the grain diameter smaller than 5mm in the matrix, correspondingly improves the content of magnesium slag and chitosan produced by silicothermic process in the additive, reduces the addition of sodium carbonate and cement, does not add sodium silicate and industrial waste silica fume with the grain diameter of more than 75 percent, reduces the quality of the recycled filler, slows down the exothermic process of hydration reaction, greatly improves the density of the recycled filler, and obtains the recycled filler with high fluidity and no shrinkage.
The environment-friendly regenerated backfill is characterized in that the molecular formula of the chitosan is provided with-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10. The chitosan of the invention has-NH 2 and-OH functional groups can effectively capture and chelate heavy metal ions in the heavy metal contaminated soil, and meanwhile, -C=O in chitosan and Ca in magnesium slag produced by silicothermic process 2+ Forming a complex, and under the condition that water exists in heavy metal contaminated soil, carrying out hydration reaction on dicalcium silicate in magnesium slag produced by adopting a silicothermic process to generate hydrated calcium silicate crystals, so that heavy metal ions enriched in chitosan in the complex are embedded into the hydrated calcium silicate crystals, and the heavy metal contaminated soil is realizedAnd (5) enriching and fixing heavy metal ions in the soil. Because the hydrated calcium silicate crystal has stable performance, is not easy to decompose or desorb, and the heavy metal ions are stably embedded in the hydrated calcium silicate crystal and are not influenced by isolation from the external environment, and are difficult to release or dissolve out, the chitosan firmly adsorbs the heavy metal ions in the soil, and locks the heavy metal ions in the environment-friendly regenerated backfill solidification process, thereby realizing the fixation and purification of the heavy metal ions in the soil.
In addition, the invention also provides a method for preparing the environment-friendly regenerated backfill material, which is characterized by comprising the following steps:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed to obtain a mixture A;
uniformly mixing sodium carbonate, sodium silicate, more than 75 industrial waste silica fume and chitosan to obtain a mixture B, and then adding the mixture B into the mixture A obtained in the step one to uniformly stir at a low speed to obtain a dry material of regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring to obtain a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a pumping or direct casting mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
The method adopts a method of stirring and mixing in sequence to prepare the wet material of the regenerated backfill, and then adopts a pumping or direct casting mode to enter a mould for maintenance, thus obtaining the environment-friendly regenerated backfill. The pumping mode is suitable for the recycled filler containing a large amount of building waste fine aggregate in the matrix, can be directly carried out on a treatment site of the building waste fine aggregate, is convenient to obtain materials, saves cost and is beneficial to quality control of the recycled filler; the direct casting mode is suitable for the regenerated backfill material containing a large amount of clay in the matrix, and the clay can be directly excavated on a construction site by adopting a stirrer for stirring preparation, so that the site conditions and construction requirements are met according to local conditions; according to the invention, the film is adopted for curing, so that the influence of the weather such as sun, rain and the like on the curing of the matrix is avoided, the later cracking caused by sudden increase or decrease of the water quantity is reduced, and the quality of the environment-friendly regenerated filler is ensured.
The method is characterized in that the rotation speed adopted by the slow stirring in the first step and the second step is 24.5r/min, and the time is 30min.
The method is characterized in that the rotation speed adopted for uniformly stirring in the third step is 45r/min, and the time is 20min.
The slow stirring in the first step and the second step of the invention avoids the flying of the raw material powder and reduces the loss; and in the third step, the rapid stirring ensures that the water and the dry materials of the regenerated backfill are fully and uniformly stirred.
Compared with the prior art, the invention has the following advantages:
1. the environment-friendly regenerated backfill material has the advantages that the fluidity, the setting time and the strength of the regenerated backfill material are effectively regulated by controlling the composition and the content of the matrix, the self weight is small, the foundation pressure is small, the settlement is avoided, the setting time can be regulated according to the working condition, the strength is regulated according to the actual requirement, the strength and the compactness of the regenerated backfill material are improved by controlling the composition and the content of the additive, the volume shrinkage is avoided, and the backfill effect is improved.
2. The environment-friendly regenerated backfill material generates calcium carbonate and sodium hydroxide at the same time, promotes the dissolution of calcium ions in dicalcium silicate with low hydration activity, and activates the hydration activity of dicalcium silicate in magnesium slag and tricalcium silicate in cement by the sodium hydroxide generated by the reaction of sodium silicate and calcium ions in the additive, thereby promoting the hydration reaction, quickly shortening the setting time of the regenerated backfill material and improving the early strength of the regenerated backfill material.
3. The silica micropowder in the industrial waste silica fume of more than 75 adopted by the invention adsorbs chitosan and forms a chitosan film on the surface of the chitosan, so that calcium ions are promoted to generate hydrated calcium silicate with hydraulic property, and the strength of the regenerated backfill is improved.
4. The invention adopts the cohesive soil, the construction waste and the magnesium slag from the magnesium smelting by the silicothermic process as the components of the environment-friendly recycled filler, thereby realizing the recycling of the construction site waste soil and the construction waste resources, improving the resource utilization rate and reducing the environmental pollution and the land occupation.
5. The environment-friendly regenerated backfill material reduces water consumption by adding the additive, is easy to realize self-leveling and self-compaction, effectively adjusts the fluidity and the setting time of the backfill material by adjusting the proportion of each component in the additive, meets the requirements of different working conditions, and is suitable for backfill areas of various topography and landforms.
6. The environment-friendly regenerated backfill 7d has unconfined compressive strength greater than 0.5MPa and 28d unconfined compressive strength greater than 0.8MPa, meets the backfill requirement in practical application, and has higher use value.
7. The chitosan adopted in the environment-friendly regenerated backfill material has the effect of chelating and fixing heavy metal ions in soil, can be used even in soil polluted to a certain extent, and has the effect of purifying the soil.
8. The preparation method of the environment-friendly regenerated backfill is simple, the construction is convenient and quick, the dry materials are prepared by mixing, the quality control of the regenerated backfill is easy to carry out by controlling the mixing ratio of the dry materials, the wet materials are prepared by adding water, the pouring position can be adjusted according to the working conditions, and the environment-friendly regenerated backfill is flexible and adaptable to various working conditions.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a physical diagram of an environment-friendly regenerated backfill material prepared in example 1 of the present invention.
FIG. 2 is a physical diagram of the environmentally friendly regenerated backfill material prepared in comparative example 1 of the present invention.
Detailed Description
Example 1
The environment-friendly regenerated backfill comprises a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 1%, and the matrix comprises the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the grain diameter of less than 5mm and 30 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: sodium carbonate 1%, magnesium slag 74.2125% by silicothermic process, cement 24.7375% and chitosan 0.5%;
the molecular formula of the chitosan has-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10.
The preparation method of the environment-friendly regenerated backfill material comprises the following steps:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a mixture A;
step two, uniformly mixing sodium carbonate, sodium silicate and chitosan to obtain a mixture B, then adding the mixture B into the mixture A obtained in the step one, and uniformly stirring at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a dry material of the regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring, wherein the adopted rotating speed is 45r/min, and the time is 20min, so as to prepare a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a direct casting mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
Comparative example 1
This comparative example differs from example 1 in that: no additive is added into the environment-friendly regenerated backfill.
Fig. 1 is a physical diagram of the environmental protection recycled filler prepared in example 1 of the present invention, fig. 2 is a physical diagram of the environmental protection recycled filler prepared in comparative example 1 of the present invention, and comparing fig. 1 and fig. 2, it can be known that the environmental protection recycled filler without the additive is cured unevenly and has micro cracks, and shrinkage occurs, the dimensional shrinkage is 1.2%, and the environmental protection recycled filler with the additive is cured evenly, has no micro cracks, is more compact, has better dimensional stability, and has the dimensional shrinkage of only 0.2%.
The wet materials of the environment-friendly recycled fillers prepared in the embodiment 1 and the comparative embodiment 1 are directly cast into cubes and subjected to film coating maintenance, so that the air blowing and the rain are avoided, the mold is removed after 24 hours for continuous maintenance, and the compressive strengths of 7d and 28d are respectively measured.
Example 2
The environment-friendly regenerated backfill comprises a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 20%, and the matrix comprises the following components in parts by mass: 90 parts of cohesive soil, 10 parts of construction waste fine aggregate with the grain diameter of less than 5mm and 30 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: 1% of sodium carbonate, 1% of sodium silicate, 48.995% of magnesium slag produced by silicothermic process, 48.995% of cement and 0.01% of chitosan;
the molecular formula of the chitosan has-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10.
The preparation method of the environment-friendly regenerated backfill material comprises the following steps:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a mixture A;
step two, uniformly mixing sodium carbonate, sodium silicate and chitosan to obtain a mixture B, then adding the mixture B into the mixture A obtained in the step one, and uniformly stirring at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a dry material of the regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring, wherein the adopted rotating speed is 45r/min, and the time is 20min, so as to prepare a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a direct casting mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
Example 3
This embodiment differs from embodiment 2 in that: the additive comprises 58.794% of magnesium slag produced by a silicothermic process and 39.196% of cement.
Example 4
This embodiment differs from embodiment 2 in that: the additive comprises 73.4925% of magnesium slag produced by a silicothermic process and 24.4975% of cement.
The fluidity and setting time of the wet materials of the reclaimed fillers prepared in examples 1 to 4 and comparative example 1 of the present invention were measured; the wet materials of the regenerated backfill materials are directly cast into cubes and subjected to film coating maintenance, the air blowing and the rain are avoided, the mold is removed after 24 hours for continuous maintenance, and the compressive strengths of 7d and 28d are respectively measured, and the results are shown in Table 1.
TABLE 1
As can be seen from table 1, the fluidity, setting time and compressive strength of the regenerated backfill prepared in examples 1 to 4 of the present invention are all superior to those of the regenerated backfill prepared in comparative example 1 without additives, demonstrating that the present invention promotes the progress of hydration reaction by adding additives, shortens the setting time of the regenerated backfill and improves the strength thereof; meanwhile, as the content of the magnesium slag of the silicon-thermal method in the additive increases, the fluidity of the reclaimed filler increases, and the setting time also increases, but the 7d compressive strength and the 28d compressive strength are both reduced, which indicates that the increase of the content of the magnesium slag of the silicon-thermal method effectively improves the fluidity and the workability of the matrix, and the slow-hardening cementing material beta-C in the magnesium slag of the silicon-thermal method 2 S and gamma-C with low hydration activity 2 S prolongs the hydration process, leads to low 28d compressive strength of the reclaimed filler, but simultaneously leads to slow hydration heat release, reduces the thermal stress in the matrix and improves the dimensional stability.
Example 5
The environment-friendly regenerated backfill comprises a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 20%, and the matrix comprises the following components in parts by mass: 90 parts of cohesive soil, 10 parts of construction waste fine aggregate with the grain diameter of less than 5mm and 30 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: sodium carbonate 1%, magnesium slag 49.495% by silicothermic process, cement 49.495% and chitosan 0.01%;
the molecular formula of the chitosan has-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10.
The preparation method of the environment-friendly regenerated backfill material comprises the following steps:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a mixture A;
step two, uniformly mixing sodium carbonate and chitosan to obtain a mixture B, then adding the mixture B into the mixture A obtained in the step one, and uniformly stirring at a slow speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a dry material of the regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring, wherein the adopted rotating speed is 45r/min, and the time is 20min, so as to prepare a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a pumping mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
Example 6
This embodiment differs from embodiment 5 in that: the additive consists of the following components in percentage by mass: 1% of sodium carbonate, 1% of sodium silicate, 48.99% of magnesium slag produced by silicothermic process, 48.99% of cement and 0.02% of chitosan.
Example 7
This embodiment differs from embodiment 5 in that: the additive consists of the following components in percentage by mass: sodium carbonate 3%, sodium silicate 3%, magnesium slag by silicothermic process 46.875%, cement 46.875% and chitosan 0.25%.
Example 8
This embodiment differs from embodiment 5 in that: the additive consists of the following components in percentage by mass: sodium carbonate 3%, sodium silicate 3%, magnesium slag by silicothermic process 46.875%, cement 46.875% and chitosan 0.5%.
Example 9
This embodiment differs from embodiment 5 in that: the additive consists of the following components in percentage by mass: 5% of sodium carbonate, 3% of sodium silicate, 45.75% of magnesium slag produced by a silicothermic process, 45.75% of cement, 4% of industrial waste silica fume above 75% and 0.5% of chitosan.
Example 10
This embodiment differs from embodiment 5 in that: the additive consists of the following components in percentage by mass: 5% of sodium carbonate, 3% of sodium silicate, 42.245% of magnesium slag produced by silicothermic process, 42.245% of cement, 7.5% of industrial waste silica fume above 75% and 0.01% of chitosan.
Detecting fluidity and setting time of the wet materials of the regenerated backfill materials prepared in the examples 5 to 10; the wet materials of the regenerated backfill materials are directly cast into cubes and subjected to film coating maintenance, the air blowing and the rain are avoided, the mold is removed after 24 hours for continuous maintenance, and the compressive strengths of 7d and 28d are respectively measured, and the results are shown in Table 2.
TABLE 2
As can be seen from Table 2, in examples 5 to 10 of the present invention, the fluidity and setting time of the recycled filler are also changed with the change of the mixing ratio of sodium carbonate, sodium silicate, chitosan and silica fume in the recycled filler additive, and the 7d compressive strength and 28d compressive strength of the environment-friendly recycled filler are both increased with the increase of the mixing ratio of sodium carbonate, sodium silicate, chitosan and silica fume, which indicates that the reaction of sodium carbonate and calcium ions to form calcium carbonate increases the strength of the recycled filler, the reaction of sodium silicate and calcium ions to form hydraulic hydrated calcium silicate and promote the hydration reaction, the setting time of the recycled filler is shortened and the early strength thereof is increased, the silica in the waste industrial silica fume of more than 75 is coated on chitosan and reacts with calcium ions to form hydrated calcium silicate, the strength of the recycled filler is increased, the chitosan forms chains to fold and form microspheres to fill in the matrix to exert the reinforcing effect, the strength of the recycled filler is further increased under the combined action of each component in the additive.
Example 11
The environment-friendly regenerated backfill comprises a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 10%, and the matrix comprises the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the grain diameter of less than 5mm and 20 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: 5% of sodium carbonate, 5% of sodium silicate, 42.75% of magnesium slag produced by silicothermic process, 42.75% of cement, 4% of industrial waste silica fume above 75% and 0.5% of chitosan;
the molecular formula of the chitosan has-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10.
The preparation method of the environment-friendly regenerated backfill material comprises the following steps:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a mixture A;
uniformly mixing sodium carbonate, sodium silicate, more than 75 industrial waste silica fume and chitosan to obtain a mixture B, and then adding the mixture B into the mixture A obtained in the step one to uniformly stir at a slow speed, wherein the adopted rotating speed is 24.5r/min, and the time is 30min, so as to obtain a dry material of regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring, wherein the adopted rotating speed is 45r/min, and the time is 20min, so as to prepare a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a direct casting mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
Example 12
This embodiment differs from embodiment 11 in that: the matrix comprises the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the particle size smaller than 5mm and 30 parts of water.
Example 13
This embodiment differs from embodiment 11 in that: the matrix comprises the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the particle size smaller than 5mm and 40 parts of water.
Example 14
This embodiment differs from embodiment 11 in that: the matrix comprises the following components in parts by mass: 10 parts of cohesive soil, 90 parts of construction waste fine aggregate with the particle size smaller than 5mm and 20 parts of water.
Detecting the fluidity and the setting time of the wet materials of the regenerated backfill materials prepared in the examples 11 to 14; the wet materials of each backfill were directly cast into cubes and cured by film coating, the air blowing and rain spraying were avoided, the mold was removed after 24 hours for continuous curing, and the compressive strengths of 7d and 28d were measured respectively, and the results are shown in Table 3.
TABLE 3 Table 3
As is clear from Table 3, in examples 11 to 14 of the present invention, as the water-solid ratio in the matrix increases, the fluidity of the reclaimed filler increases, and the setting time increases, but the 7d compressive strength and the 28d compressive strength are both lower, which means that the presence of free water in the reclaimed filler increases the inter-particle distance between the matrix and the additive, so that the hydration reaction is less likely to occur, the strength of the reclaimed filler increases slowly, and as the free water content increases, the proportion of dry material decreases, the amount of each raw material participating in the hydration reaction decreases, causing a further decrease in the strength of the reclaimed filler.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.
Claims (7)
1. The environment-friendly regenerated backfill is characterized by comprising a matrix and an additive, wherein the additive is added into the matrix in a mass percentage of 1-20%, and the matrix consists of the following components in parts by mass: 10-90 parts of cohesive soil, 10-90 parts of construction waste fine aggregate with the grain diameter smaller than 5mm and 20-40 parts of water, wherein the organic matter content of the cohesive soil is not more than 3%, the grain diameter of non-organic matter solid waste is not more than 50mm, and the additive consists of the following components in percentage by mass: 1 to 5 percent of sodium carbonate, 0 to 5 percent of sodium silicate, 42 to 75 percent of magnesium slag produced by a silicothermic process, 25 to 50 percent of cement, 0 to 7.5 percent of industrial waste silica fume above 75 percent and 0.01 to 0.5 percent of chitosan.
2. The environment-friendly regenerated backfill according to claim 1, wherein the addition percentage by mass of the additive in the matrix is 20%, and the matrix comprises the following components in parts by mass: 90 parts of clay, 10 parts of construction waste fine aggregate with the particle size smaller than 5mm and 30 parts of water, wherein the additive comprises the following components in percentage by mass: 5% of sodium carbonate, 3% of sodium silicate, 42.245% of magnesium slag produced by silicothermic process, 42.245% of cement, 7.5% of industrial waste silica fume above 75% and 0.01% of chitosan.
3. The environment-friendly regenerated backfill according to claim 1, wherein the addition percentage by mass of the additive in the matrix is 10%, and the matrix comprises the following components in parts by mass: 50 parts of cohesive soil, 50 parts of construction waste fine aggregate with the particle size smaller than 5mm and 30 parts of water, wherein the additive comprises the following components in percentage by mass: sodium carbonate 1%, magnesium slag 74.2125% by silicothermic process, cement 24.7375% and chitosan 0.05%.
4. An environmentally friendly recycled filler according to claim 1, wherein said chitosan has the formula of-NH 2 -c=o and-OH functions, chitosan having a degree of deacetylation lower than 80%, a molecular weight higher than 5000 and being completely soluble in water having a pH higher than 10.
5. A process for preparing an environmentally friendly reclaimed filler as claimed in any one of claims 1 to 4, comprising the steps of:
firstly, mixing magnesium slag, cement, clay and construction waste fine aggregate with the particle size smaller than 5mm obtained by adopting a silicothermic process after natural air cooling, and then stirring uniformly at a low speed to obtain a mixture A;
uniformly mixing sodium carbonate, sodium silicate, more than 75 industrial waste silica fume and chitosan to obtain a mixture B, and then adding the mixture B into the mixture A obtained in the step one to uniformly stir at a low speed to obtain a dry material of regenerated backfill;
adding water into the dry material of the regenerated backfill material obtained in the step two, and uniformly stirring to obtain a wet material of the regenerated backfill material;
and step four, filling the wet material of the regenerated backfill obtained in the step three into a mould by adopting a pumping or direct casting mode, and performing film coating maintenance to obtain the environment-friendly regenerated backfill.
6. The method according to claim 5, wherein the slow stirring in the first and second steps is performed at a rotation speed of 24.5r/min for 30min.
7. The method according to claim 5, wherein the stirring in the third step is performed at a rotation speed of 45r/min for 20min.
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