CN112919864A - Recycled aggregate fiber reinforced shotcrete and preparation method thereof - Google Patents
Recycled aggregate fiber reinforced shotcrete and preparation method thereof Download PDFInfo
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- 239000011378 shotcrete Substances 0.000 title abstract description 38
- 238000002360 preparation method Methods 0.000 title abstract description 9
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- 239000004567 concrete Substances 0.000 description 26
- 229910000831 Steel Inorganic materials 0.000 description 23
- 239000010959 steel Substances 0.000 description 23
- 239000002253 acid Substances 0.000 description 14
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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
- C04B28/02—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 containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland 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
- C04B14/38—Fibrous materials; Whiskers
- C04B14/383—Whiskers
-
- 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
- C04B2111/00034—Physico-chemical characteristics of the mixtures
- C04B2111/00146—Sprayable or pumpable mixtures
- C04B2111/00155—Sprayable, i.e. concrete-like, materials able to be shaped by spraying instead of by casting, e.g. gunite
-
- 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
- C04B2111/20—Resistance against chemical, physical or biological attack
-
- 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
- C04B2111/20—Resistance against chemical, physical or biological attack
- C04B2111/2015—Sulfate resistance
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses recycled aggregate fiber reinforced shotcrete which is prepared from the following raw materials in parts by weight: 100 parts of a cementing material, 75-85 parts of cement, 12-15 parts of fly ash, 6-8 parts of silica fume and 150-168 parts of 5-10 mm broken stone; 39-42 parts of 5-10 mm recycled coarse aggregate, 193-203 parts of sand, 18-23 parts of 0.15-5 mm recycled fine aggregate and 6-8 parts of polypropylene fiber; 40-45 parts of mixing water, 1.5-4.5 parts of a water reducing agent, 0.1-1 part of a thickening agent and 6-8 parts of an accelerating agent. The invention also discloses a preparation method of the recycled aggregate fiber reinforced shotcrete. The sprayed concrete has good crack resistance, impermeability and corrosion resistance, and has the characteristics of rapidness, early strength, simple construction process and the like.
Description
Technical Field
The invention relates to the technical field of building materials. More specifically, the invention relates to recycled aggregate fiber reinforced shotcrete and a preparation method thereof.
Background
The sprayed concrete is delivered by means of spraying machine and compressed air or other power source through pipeline, and is sprayed onto the sprayed surface at high speed, and is quickly coagulated and hardened to form concrete adhered to the sprayed surface. At present, with the development, application and popularization of wet spraying technology and the fact that a single-layer spray anchor supporting structure form is more and more favored by underground structure researchers, fiber reinforced shotcrete is more and more widely applied to tunnel anchor spraying support, and researches show that the application of the fiber reinforced shotcrete is mainly made of steel fibers. However, the steel fiber has the defects of large consumption, high cost, uneven stirring, easy scratching of human bodies and easy corrosion of the jet resilience material, and the like, so that the popularization and further application of the steel fiber concrete are seriously influenced. Therefore, a large number of researchers have studied crude polypropylene fibers which can replace steel fibers or replace steel fibers, and the crude polypropylene fibers have the advantages of easy dispersion, low cost and corrosion resistance, and the mechanical properties of the crude polypropylene fibers are almost the same as those of the steel fibers.
Currently, for the china with relatively poor natural resources, the development of a new sustainable development model of the construction industry is not slow. In order to fully utilize the building solid wastes, the preparation technology of the recycled aggregate is used as a new green and environment-friendly technology, so that the application of the recycled aggregate in the sprayed concrete becomes a hot door, natural resources and energy such as sand and stone can be saved, and good environmental, economic and social benefits are achieved. However, the recycled aggregate concrete has the defects of high crushing index, low aggregate hardness, large porosity and the like, and the polypropylene fiber is used as a material with excellent reinforcing, toughening and crack-resisting functions, so that the preparation and application of the fiber-reinforced recycled aggregate sprayed concrete are possible.
Disclosure of Invention
The invention aims to provide recycled aggregate fiber reinforced shotcrete and a preparation method thereof.
To achieve these objects and other advantages in accordance with the present invention, there is provided a recycled aggregate fiber reinforced shotcrete, comprising the following raw materials: 100 parts of a cementing material, 75-85 parts of cement, 12-15 parts of fly ash, 6-8 parts of silica fume and 150-168 parts of 5-10 mm broken stone; 39-42 parts of 5-10 mm recycled coarse aggregate, 193-203 parts of sand, 18-23 parts of 0.15-5 mm recycled fine aggregate and 6-8 parts of polypropylene fiber; 40-45 parts of mixing water, 1.5-4.5 parts of a water reducing agent, 0.1-1 part of a thickening agent and 6-8 parts of an accelerating agent.
Preferably, the cement is one of PO42.5 ordinary portland cement, PI42.5 portland cement or PO42.5R ordinary portland cement, the fly ash is commercial grade I or II fly ash, and the silica fume is superfine silica fume, wherein SiO is2The content is more than or equal to 95.0.
Preferably, the gravel is one or a mixture of granite gravel, limestone gravel and tuff gravel, and the sand is one or a mixture of river sand and machine-made sand.
Preferably, the recycled coarse aggregate is waste concrete aggregate, the property of the recycled coarse aggregate meets the standard of GB/T25177-2010 recycled coarse aggregate for concrete, and the property of the recycled fine aggregate is waste concrete aggregate, and the property of the recycled fine aggregate meets the standard of GB/T25176 and 2010 recycled fine aggregate for concrete and mortar.
Preferably, the polypropylene fibers are coarse fibers having a fiber length of 30mm and a diameter of 0.73 mm.
Preferably, the thickening agent is any one or more of cellulose ether, polyacrylamide and polyvinyl alcohol, the water reducing agent is a polycarboxylic acid high-performance water reducing agent, the water reducing agent can be a polyester polycarboxylic acid water reducing agent, a polyether polycarboxylic acid water reducing agent or an amide/imide polycarboxylic acid water reducing agent, and the accelerating agent is one of a low-alkali or alkali-free high-aluminum accelerating agent.
Preferably, the composition further comprises the following components: 0-0.5 part of steel fiber.
Preferably, the steel fibers are copper-plated steel fibers with a diameter of 0.1mm and a length of 13 mm.
Preferably, the composition further comprises the following components: 0-0.5 part of calcium carbonate crystal whisker, and the granularity of the calcium carbonate crystal whisker is less than 0.8 mm.
The invention also provides a preparation method of the recycled aggregate fiber reinforced shotcrete, which comprises the following steps:
the method comprises the following steps: mixing and stirring sand, recycled fine aggregate, fiber or/and calcium carbonate whisker and 30% of water for 1min to form a wet state, then stirring the wet state with cement, fly ash and silica fume concrete for 30s, then adding broken stone, two kinds of grain diameter recycled coarse aggregate, the rest 70% of water, a thickening agent and a water reducing agent, mixing and stirring for 1min, and then putting the mixture into a spraying machine;
step two: then the accelerator is filled into a nozzle, and the concrete is sprayed to the sprayed surface by using compressed air.
The invention at least comprises the following beneficial effects:
the recycled aggregate fiber reinforced shotcrete disclosed by the invention is used as a novel environment-friendly building material, and the effects of reinforcement, crack resistance, toughening, modification and the like of fibers and calcium carbonate whiskers are utilized to make up for the defects of recycled aggregates to a certain extent, the resilience rate of the recycled aggregate fiber reinforced shotcrete can be reduced to be below 12%, the corrosion resistance coefficient of concrete is improved to be above 90%, the corrosion resistance grade of concrete against sulfate is improved to be below KS150, and the diffusion coefficient of chloride ions is reduced to be 1.5 multiplied by 10-12m2The ratio of the water to the water is less than s.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a flow chart of the shotcrete preparation process of the present invention.
Detailed Description
The present invention is further described in detail below with reference to examples so that those skilled in the art can practice the invention with reference to the description.
It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified.
The polypropylene fibers in the following examples and comparative examples were coarse fibers having a fiber length of 30mm and a diameter of 0.73 mm; the steel fiber is copper-plated steel fiber with the diameter of 0.1mm and the length of 13 mm; the calcium carbonate crystal whisker has a particle size of 0.8mm or less.
Example 1
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm recycled coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm recycled fine aggregate and 8 parts of polypropylene fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Example 2
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber and 0.1 part of steel fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Example 3
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber and 0.5 part of steel fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Example 4
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber, 0.1 part of steel fiber and 0.2 part of calcium carbonate whisker; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Example 5
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber and 0.2 part of calcium carbonate whisker; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Comparative example 1
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm recycled coarse aggregate, 200 parts of river sand and 8 parts of polypropylene fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Comparative example 2
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of recycled coarse aggregate of 5-10 mm, 200 parts of river sand, 8 parts of polypropylene fiber and 0.1 part of steel fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Comparative example 3
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber and 1 part of steel fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Comparative example 4
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of 5-10 mm regenerated coarse aggregate, 200 parts of river sand, 20 parts of 0.15-5 mm regenerated fine aggregate, 8 parts of polypropylene fiber and 8 parts of steel fiber; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
Comparative example 5
The recycled aggregate fiber reinforced shotcrete comprises the following raw materials: 100 parts of a cementing material, 80 parts of PO42.5R ordinary portland cement, 12 parts of I-grade fly ash, 7 parts of superfine silica fume and 158 parts of 5-10 mm granite gravel; 40 parts of recycled coarse aggregate with the thickness of 5-10 mm, 200 parts of river sand, 8 parts of polypropylene fiber, 0.1 part of steel fiber and 0.2 part of calcium carbonate whisker; 45 parts of mixing water, 3 parts of a polycarboxylic acid high-performance water reducing agent, 0.6 part of a cellulose ether thickening agent and 8 parts of an alkali-free high-aluminum accelerator.
The recycled aggregate fiber-reinforced shotcretes of examples 1 to 5 and comparative examples 1 to 5 were prepared as follows, and the method specifically included the following steps:
the method comprises the following steps: mixing and stirring sand, recycled fine aggregate, fiber or/and calcium carbonate whisker and 30% of water for 1min to form a wet state, then stirring the wet state with cement, fly ash and silica fume concrete for 30s, then adding broken stone, two kinds of grain diameter recycled coarse aggregate, the rest 70% of water, a thickening agent and a water reducing agent, mixing and stirring for 1min, and then putting the mixture into a spraying machine;
step two: then the accelerator is filled into a nozzle, and the concrete is sprayed to the sprayed surface by using compressed air.
After the concrete spraying of examples 1 to 5 and comparative examples 1 to 5 was completed, the test pieces were cured with a mold for 1 day, demolded, cured for 7 days, and cut to form test pieces having a concrete size of 100mm × 100mm × 100mm, and the sprayed concrete cube test pieces were cured for 21 days under standard conditions of a temperature of 25 ± 5 ℃ and a Relative Humidity (RH) of 98%. After the initial curing for 28d, the shotcrete specimens were immersed in 5 wt% Na2SO4Long term exposure to the solution is experienced. The concrete-related properties were tested, and the test results are shown in the following table.
Example 1 in comparison to examples 2 and 3, steel fibers were added to shotcrete in combination with polypropylene fibers to further improve various properties of the shotcrete.
Compared with the embodiment 4, the embodiment 2 and the embodiment 3 can further improve various performances of the sprayed concrete by adding calcium carbonate whiskers and fibers into the sprayed concrete.
Examples 2 and 3, 4 and 5 compare, and the simultaneous addition of steel fibers and calcium carbonate whiskers is more significant in improving various properties of shotcrete than the addition of only steel fibers or calcium carbonate whiskers.
In comparison with examples 1, 2 and 4 and comparative examples 1, 2 and 5, respectively, the addition of the recycled fine aggregate and the recycled coarse aggregate for blending is more significant in improving various performances of the shotcrete than the addition of the recycled coarse aggregate alone.
Examples 2 and 3 are compared with comparative examples 3 and 4, and the steel fibers must be added within a given range to improve various properties of shotcrete, otherwise the various properties of shotcrete are significantly reduced.
The addition of admixtures such as fly ash and silica fume into the recycled concrete can effectively improve the sulfate erosion resistance of the concrete, and after the active admixtures are added into the concrete, the content of calcium hydroxide can be reduced, and the active admixtures can also generate secondary hydration reaction with cement hydration products. The product mainly fills capillary pores of the cement stone, improves the compactness of the cement stone, reduces the porosity of cement, and makes it more difficult for a sulfate medium to be immersed into the concrete. In addition, secondary hydration reactions retard gypsum crystallization. Due to the secondary hydration reaction, the content of cement in set cement and the concentration of lime in capillary holes are reduced, and the speed and the quantity of gypsum crystallization are greatly reduced even in sulfate environment water with high concentration, so that the sulfate corrosion resistance of concrete is enhanced by enhancing regeneration.
The calcium carbonate whisker micron-sized fiber is used for improving the microstructure of the recycled concrete material, limiting the generation and development of internal microscale cracks and realizing the microscale reinforcement of the recycled concrete; the PVA millimeter-scale fiber is used for optimizing the microscopic structure of the recycled concrete material, the micro cracks in the material are limited to penetrate and fuse into microscopic scale cracks, the further growth and expansion of the microscopic cracks are hindered, and the microscopic reinforcement of the concrete material is realized; the macroscopic performance of the concrete can be improved by using the fibers of the same centimeters as the steel fibers, the functions of crack limiting and bearing are exerted by bridging macroscopic cracks, and the progressive reinforcement of the fibers of all scales and the positive hybrid reinforcement effect of the fibers of all scales are finally realized.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable to various fields of endeavor for which the invention may be embodied with additional modifications as would be readily apparent to those skilled in the art, and the invention is therefore not limited to the details given herein and to the embodiments shown and described without departing from the generic concept as defined by the claims and their equivalents.
Claims (10)
1. The recycled aggregate fiber reinforced shotcrete is characterized by comprising the following raw materials: 100 parts of a cementing material, 75-85 parts of cement, 12-15 parts of fly ash, 6-8 parts of silica fume and 150-168 parts of 5-10 mm broken stone; 39-42 parts of 5-10 mm recycled coarse aggregate, 193-203 parts of sand, 18-23 parts of 0.15-5 mm recycled fine aggregate and 6-8 parts of polypropylene fiber; 40-45 parts of mixing water, 1.5-4.5 parts of a water reducing agent, 0.1-1 part of a thickening agent and 6-8 parts of an accelerating agent.
2. The recycled aggregate fiber-reinforced shotcrete as claimed in claim 1, wherein the cement is one of PO42.5 portland cement, PI42.5 portland cement, or PO42.5R portland cement, the fly ash is commercially available class I or II fly ash, and the fly ash is ultra-fine silica fume, wherein SiO is in the class I or II fly ash2The content is more than or equal to 95.0.
3. The recycled aggregate fiber reinforced shotcrete as claimed in claim 1, wherein the crushed stone is one or a mixture of granite crushed stone, limestone crushed stone and tuff crushed stone, and the sand is one or a mixture of river sand and machine-made sand.
4. The recycled aggregate fiber-reinforced shotcrete as claimed in claim 1, wherein the recycled coarse aggregate is waste concrete aggregate, the recycled coarse aggregate properties meet the GB/T25177-2010 recycled coarse aggregate for concrete, and the recycled fine aggregate is waste concrete aggregate, the recycled fine aggregate properties meet the GB/T25176-2010 recycled fine aggregate for concrete and mortar.
5. The recycled aggregate fiber-reinforced shotcrete according to claim 1, wherein the polypropylene fibers are coarse fibers having a fiber length of 30mm and a diameter of 0.73 mm.
6. The recycled aggregate fiber reinforced shotcrete as claimed in claim 1, wherein the thickener is any one or more of cellulose ether, polyacrylamide and polyvinyl alcohol, the water reducer is a polycarboxylic acid high-performance water reducer, the water reducer is a polyester polycarboxylic acid water reducer, a polyether polycarboxylic acid water reducer, an amide/imide polycarboxylic acid water reducer, and the accelerator is one of a low-alkali or alkali-free high-alumina accelerator.
7. The recycled aggregate fiber reinforced shotcrete of claim 1, further comprising the components: 0-0.5 part of steel fiber.
8. The recycled aggregate fiber-reinforced shotcrete according to claim 7, wherein the steel fibers are copper-plated steel fibers having a diameter of 0.1mm and a length of 13 mm.
9. The recycled aggregate fiber reinforced shotcrete of claim 1, further comprising the components: 0-0.5 part of calcium carbonate crystal whisker, and the granularity of the calcium carbonate crystal whisker is less than 0.8 mm.
10. The preparation method of the recycled aggregate fiber reinforced shotcrete is characterized by comprising the following steps:
the method comprises the following steps: mixing and stirring sand, recycled fine aggregate, fiber or/and calcium carbonate whisker and 30% of water for 1min to form a wet state, then stirring the wet state with cement, fly ash and silica fume concrete for 30s, then adding broken stone, two kinds of grain diameter recycled coarse aggregate, the rest 70% of water, a thickening agent and a water reducing agent, mixing and stirring for 1min, and then putting the mixture into a spraying machine;
step two: then the accelerator is filled into a nozzle, and the concrete is sprayed to the sprayed surface by using compressed air.
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Application publication date: 20210608 |