CN116986839A - Recycled coarse aggregate batch strengthening method and curb preparation method based on same - Google Patents
Recycled coarse aggregate batch strengthening method and curb preparation method based on same Download PDFInfo
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- CN116986839A CN116986839A CN202310896274.2A CN202310896274A CN116986839A CN 116986839 A CN116986839 A CN 116986839A CN 202310896274 A CN202310896274 A CN 202310896274A CN 116986839 A CN116986839 A CN 116986839A
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- 238000000034 method Methods 0.000 title claims abstract description 39
- 238000005728 strengthening Methods 0.000 title claims abstract description 26
- 238000002360 preparation method Methods 0.000 title abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000002131 composite material Substances 0.000 claims abstract description 32
- 239000002699 waste material Substances 0.000 claims abstract description 30
- 238000010276 construction Methods 0.000 claims abstract description 26
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000005299 abrasion Methods 0.000 claims abstract description 15
- 239000002994 raw material Substances 0.000 claims abstract description 15
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 11
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 11
- 238000003763 carbonization Methods 0.000 claims abstract description 11
- 238000006243 chemical reaction Methods 0.000 claims abstract description 10
- 238000005507 spraying Methods 0.000 claims abstract description 10
- 230000002787 reinforcement Effects 0.000 claims abstract description 6
- 239000002002 slurry Substances 0.000 claims abstract description 6
- 239000011248 coating agent Substances 0.000 claims abstract description 5
- 238000000576 coating method Methods 0.000 claims abstract description 5
- 239000002245 particle Substances 0.000 claims description 66
- 239000004576 sand Substances 0.000 claims description 43
- 239000004568 cement Substances 0.000 claims description 41
- 239000004567 concrete Substances 0.000 claims description 38
- 239000010881 fly ash Substances 0.000 claims description 27
- 238000003756 stirring Methods 0.000 claims description 25
- 239000003638 chemical reducing agent Substances 0.000 claims description 15
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 12
- 239000002956 ash Substances 0.000 claims description 10
- 238000002791 soaking Methods 0.000 claims description 9
- 239000003795 chemical substances by application Substances 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 230000003014 reinforcing effect Effects 0.000 claims description 7
- 239000012258 stirred mixture Substances 0.000 claims description 7
- 238000012216 screening Methods 0.000 claims description 5
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- 238000007873 sieving Methods 0.000 claims description 4
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- 238000005273 aeration Methods 0.000 claims 2
- 238000010521 absorption reaction Methods 0.000 abstract description 11
- 239000004570 mortar (masonry) Substances 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 6
- 239000011148 porous material Substances 0.000 abstract description 3
- 238000004064 recycling Methods 0.000 abstract description 3
- 239000004566 building material Substances 0.000 abstract description 2
- 238000005096 rolling process Methods 0.000 abstract description 2
- 230000002195 synergetic effect Effects 0.000 abstract description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 38
- 239000000463 material Substances 0.000 description 14
- 238000012423 maintenance Methods 0.000 description 13
- 239000011398 Portland cement Substances 0.000 description 8
- 229910000831 Steel Inorganic materials 0.000 description 8
- 239000010959 steel Substances 0.000 description 8
- 239000011083 cement mortar Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000005056 compaction Methods 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 229910021487 silica fume Inorganic materials 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229920005646 polycarboxylate Polymers 0.000 description 4
- 239000004575 stone Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 235000019738 Limestone Nutrition 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 239000006028 limestone Substances 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 229920002125 Sokalan® Polymers 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 239000000378 calcium silicate Substances 0.000 description 2
- 229910052918 calcium silicate Inorganic materials 0.000 description 2
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000012615 aggregate Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010170 biological method Methods 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
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- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- 229910001653 ettringite Inorganic materials 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009440 infrastructure construction Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
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Classifications
-
- 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
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/10—Coating or impregnating
- C04B20/12—Multiple coating or impregnating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/08—Producing shaped prefabricated articles from the material by vibrating or jolting
- B28B1/087—Producing shaped prefabricated articles from the material by vibrating or jolting by means acting on the mould ; Fixation thereof to the mould
- B28B1/0873—Producing shaped prefabricated articles from the material by vibrating or jolting by means acting on the mould ; Fixation thereof to the mould the mould being placed on vibrating or jolting supports, e.g. moulding tables
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B17/00—Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping
- B28B17/02—Conditioning the material prior to shaping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B7/00—Moulds; Cores; Mandrels
- B28B7/38—Treating surfaces of moulds, cores, or mandrels to prevent sticking
- B28B7/388—Treating surfaces of moulds, cores, or mandrels to prevent sticking with liquid material, e.g. lubricating
-
- 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
- C04B18/16—Waste materials; Refuse from building or ceramic industry
-
- 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
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Road Paving Structures (AREA)
Abstract
The invention relates to a recycled coarse aggregate batch strengthening method and a curb preparation method based on the recycled coarse aggregate batch strengthening method, and belongs to the technical field of building materials. According to the invention, through rolling abrasion, the sharp edges and corners of the building rubbish recycled coarse aggregate are effectively removed, and weak mortar is wrapped; the internal cracks are filled up through carbon dioxide carbonization reaction, volcanic slurry reinforcement and waterproof coating spraying in various modes, water absorption pores are plugged, and the synergistic reinforcement effect of various effects is achieved. The curb produced by taking the composite reinforced recycled coarse aggregate as the raw material has excellent performance and realizes the recycling utilization of the construction waste.
Description
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to a recycled coarse aggregate batch strengthening method and a curb preparation method based on the recycled coarse aggregate batch strengthening method.
Background
The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.
At present, the construction waste is generally treated by direct landfill and open-air stacking, occupies a large amount of land and causes serious ecological environmental pollution. On the other hand, with the vigorous development of infrastructure construction, the demand of natural resources such as sand and stone is continuously increased, the contradiction between the high-speed development of engineering construction and the shortage of natural aggregate is gradually sharp, and the realization of the coordinated development between the wide application of concrete materials and the ecological environment has become a current big subject. The main components of the construction waste, such as concrete, brick blocks, mortar blocks and the like, are inorganic materials, and the materials have the characteristics of strong alkali resistance, water stability, chemical stability, corrosion resistance and the like, and are difficult to degrade, so that the construction waste is recycled and used as recycled aggregate, and the construction waste has the potential of replacing natural sand and stone. Because the construction waste recycled aggregate surface is coated with weak mortar and has numerous microcracks and pores, the basic physical properties and strength of the construction waste recycled aggregate are inferior to those of natural mineral aggregates, such as the recycled aggregate has lower density and higher water absorption and crushing value, and therefore, the performance of the construction waste recycled aggregate, particularly the coarse aggregate, is required to be enhanced.
Partial results are obtained aiming at the recycled aggregate performance strengthening method comprising a physical method, a chemical method and a biological method, but the current research conclusion lacks a low-cost and batched performance strengthening mode to support the recycling of the recycled aggregate of the construction waste, and does not form a standardized performance improving technology, so that the recycled aggregate is high in strengthening cost and poor in environmental benefit, and is difficult to popularize and apply on a large scale. In addition, for different application scenes, the performance requirements on the recycled coarse aggregate are different, and a strengthening method is required to be selected in a targeted manner aiming at the application scenes of the recycled coarse aggregate.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a regenerated coarse aggregate batch strengthening method and a curb preparation method based on the same. The physical properties of the building rubbish recycled coarse aggregate are improved by a composite strengthening method combining a plurality of strengthening methods, so that the mechanical properties and the durability of the curb used for producing the building rubbish recycled coarse aggregate are enhanced, the material cost is saved, and the problems that the existing building rubbish recycled aggregate strengthening method is high in cost and difficult to produce and apply on a large scale can be effectively solved.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
in a first aspect, a method for batch strengthening of recycled coarse aggregate includes the steps of:
(1) Crushing and screening the cement concrete construction waste to obtain a recycled coarse aggregate raw material;
(2) Abrading the recycled coarse aggregate raw material, sieving the recycled coarse aggregate particles obtained after abrasion, retaining the particles in the sieve and washing with water;
(3) Immersing the recycled coarse aggregate particles in a calcium hydroxide solution, and uniformly introducing carbon dioxide gas into the solution to obtain the recycled coarse aggregate particles subjected to carbonization reaction;
(4) Uniformly immersing the regenerated coarse aggregate particles subjected to carbonization reaction into a volcanic ash slurry pond, and drying to obtain pretreated regenerated coarse aggregate particles;
(5) And spraying the pretreated recycled coarse aggregate particles with waterproof paint, and drying to obtain the composite reinforced recycled coarse aggregate.
In the step (1), crushing the concrete construction waste to a grain size range of 5-20 mm by multiple times of crushing;
in the step (2), the recycled coarse aggregate raw material is put into an abrasion tester for abrasion according to the specification of an abrasion tester, the abraded recycled coarse aggregate particles are filtered through a square-hole sieve with the particle size of 4.75mm, and the particles with the particle size of 5mm to 20mm in the sieve are reserved;
in the step (3), the concentration of the calcium hydroxide solution is 10-20 g/L, the ventilation rate of carbon dioxide is 1-1.5L/h, and the soaking time of the regenerated coarse aggregate particles is 24h;
in the step (4), the volcanic ash solution is prepared from cement and silica fume according to the weight ratio of 8:2 with water, wherein the concentration of the volcanic ash solution is 10-20 g/L, and the soaking time of the regenerated coarse aggregate particles after carbonization reaction is 3-6 h;
in the step (5), the waterproof coating is pure acrylic acid polymer emulsion, and the spraying amount is 3-6% of the mass of the pretreated regenerated coarse aggregate particles.
In the second aspect, the composite reinforced recycled coarse aggregate is prepared by the batch reinforcing method for the recycled coarse aggregate.
In a third aspect, the curb based on the composite reinforced recycled coarse aggregate comprises 1100-1300 parts of the composite reinforced recycled coarse aggregate, 300-400 parts of cement, 40-80 parts of fly ash, 600-750 parts of sand and 20-80 parts of water reducer;
wherein the sand is a mixture of machine-made sand and fine sand, and the mass ratio of the machine-made sand to the fine sand is 8:2, the grain size of the recycled coarse aggregate is 5-20 mm, the cement is ordinary Portland cement with the grade of P.O 42.5 or more, and the fly ash is fly ash with the grade of II or more.
In a fourth aspect, a method for producing a curb based on the composite reinforced recycled coarse aggregate.
The method comprises the following specific steps:
(1) Preparing composite reinforced recycled coarse aggregate according to the batch reinforcing method of the recycled coarse aggregate;
(2) Stirring cement, fly ash, water and a water reducing agent to prepare cement paste;
(3) Adding the composite reinforced recycled coarse aggregate and stirring to fully mix the cement paste and the recycled aggregate;
(4) Adding sand, and fully stirring;
(5) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table to be compact, standing for 24 hours at room temperature, demoulding the obtained concrete curb, naturally sprinkling water to maintain the demoulded concrete curb, and keeping the surface of the concrete moist.
Wherein the sand is a mixture of machine-made sand and fine sand with good grading and fineness modulus of 2.3-2.7, and the mass ratio of the machine-made sand to the fine sand is 8:2, the grain size of the recycled coarse aggregate is 5-20 mm, the cement is ordinary Portland cement with the grade of P.O 42.5 or more, and the fly ash is fly ash with the grade of II or more.
The beneficial effects of the invention are as follows:
1. according to the invention, through rolling abrasion, the sharp edges and corners of the building rubbish recycled coarse aggregate are effectively removed, and weak mortar is wrapped; the internal cracks are filled up through carbon dioxide carbonization reaction, volcanic slurry reinforcement and waterproof coating spraying in various modes, water absorption pores are plugged, and the synergistic reinforcement effect of various effects is achieved.
2. The mechanical equipment used by the method for reinforcing the recycled coarse aggregate in batches is common equipment, can be used for automatic production, and can realize the mass reinforced production of the recycled coarse aggregate of the construction waste.
3. The invention adopts the construction waste coarse aggregate as the raw material to manufacture the curb, realizes the resource utilization of the construction waste, and has excellent working performance of the produced curb.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
FIG. 1 is a schematic flow chart of a method for strengthening regenerated coarse aggregate in batches in the invention;
fig. 2 is a process for preparing a curb based on composite reinforced recycled coarse aggregate in accordance with the present invention.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
As shown in FIG. 1, the invention provides a method for reinforcing recycled coarse aggregate in batches, which comprises the following steps:
(1) Crushing and screening the cement concrete construction waste to obtain a recycled coarse aggregate raw material;
specifically, cement concrete construction waste refers to construction waste that does not contain clinker (e.g., bricks, tiles, etc.); such as waste concrete beams, waste concrete columns, waste concrete slabs and the like, and removing other materials such as steel bars, saw dust, plastics and the like to obtain cement concrete construction waste;
crushing by adopting a jaw crusher, screening the crushed regenerated coarse aggregate by adopting a square-hole sieve, and secondarily crushing the crushed particles with the particle size of more than 20mm.
The crushed recycled coarse aggregate mainly comprises original natural aggregate and attached cement mortar, and has sharp edges and corners, and cracks are formed at the interfaces of part of cement mortar and natural aggregate, so that the water absorption rate of the recycled aggregate is higher due to the existence of the cement mortar and the weak interfaces of the cement mortar and the natural aggregate, and the recycled aggregate becomes a weak link when bearing pressure, so that the aggregate is easy to crush.
(2) Abrading the recycled coarse aggregate raw material, sieving the recycled coarse aggregate particles obtained after abrasion, retaining the particles in the sieve and washing with water;
specifically, the recycled coarse aggregate raw material is placed in a large abrasion tester, a proper amount of steel balls are placed in the large abrasion tester, the number of the steel balls is 0.5-2/kg, the mass of each steel ball is 390-445 g, the rotating speed is controlled to be 100-300 r/min, the recycled coarse aggregate particles pass through a square hole sieve with the particle size of 4.75mm after 5-20 minutes of operation, weak mortar on the surface of the particles is removed through mutual collision friction of the particles, the particles with the particle size of 5-20 mm are reserved, and the next operation is carried out after water washing.
The method has the advantages that the weak mortar and sharp edges, which are attached to the recycled coarse aggregate, are removed through the direct collision and friction actions of the recycled coarse aggregate raw material, the recycled coarse aggregate raw material and the steel balls, the components of the natural aggregate-like firmness degree in the recycled aggregate are reserved, the surface particles are removed easily through water washing, the attached tiny dust in the tiny gaps is cleaned, the penetration of the strengthening component into the gaps in the subsequent strengthening step is promoted, the strengthening effect is enhanced, the surface cleanliness of the waste concrete particles is improved, and the bonding strength with cement mortar is increased.
(3) Immersing the recycled coarse aggregate particles in a calcium hydroxide solution, and uniformly introducing carbon dioxide gas into the solution to obtain the recycled coarse aggregate particles subjected to carbonization reaction;
specifically, the regenerated coarse aggregate particles are scattered and paved on a large screen to be immersed in a calcium hydroxide solution, the concentration of the calcium hydroxide solution is 10-20 g/L, the ventilation rate of carbon dioxide is 1-1.5L/h, the immersing time of the regenerated coarse aggregate particles is 24h, and the screen is vibrated for 15-30 min every 3 h.
The effect of this treatment mode is: by CO 2 The recycled coarse aggregate reacts with the surface of the old mortar layer of the recycled aggregate containing a large amount of calcium hydroxide, hydrated calcium silicate, ettringite and sulfate in the alkaline environment provided by the calcium hydroxide to primarily repair microcracks in the recycled coarse aggregate, so that the strength of the recycled coarse aggregate is enhanced.
(4) Uniformly immersing the regenerated coarse aggregate particles subjected to carbonization reaction into a volcanic ash slurry pond, and drying to obtain pretreated regenerated coarse aggregate particles;
specifically, the volcanic ash solution is prepared from cement and silica fume according to a weight ratio of 8:2, the cement is selected from common silicate 42.5 cement produced by Shandong Shanshui group, the silica fume is selected from high-quality silica fume produced by Henan platinum new material company, the silica content is more than or equal to 98%, the concentration of the volcanic ash solution is 10-20 g/L, the soaking time of the regenerated coarse aggregate particles is 3-6 h, and the screen is vibrated for 15-20 min every 1 h.
This step is carried over by the pozzolan solution with the Ca (OH) remaining in the recycled coarse aggregate and in the previous step 2 And (3) generating secondary hydration to finally generate hydrated calcium silicate (C-S-H) gel, and filling the cracks which are not repaired by carbonization reaction.
(5) Spraying waterproof paint on the pretreated recycled coarse aggregate particles, continuously stirring the recycled coarse aggregate in the spraying process so as to uniformly wrap the paint, and naturally drying the sprayed recycled coarse aggregate to obtain the composite reinforced recycled coarse aggregate;
specifically, the waterproof coating is pure acrylic acid polymer emulsion, the spraying amount is 3-6% of the mass of the recycled coarse aggregate particles, cracks and holes on the surface of the recycled coarse aggregate are further plugged, and the water absorption rate of the recycled coarse aggregate is reduced.
Correspondingly, the invention also discloses a composite reinforced recycled coarse aggregate, which is prepared by the batch reinforcing method for the recycled coarse aggregate.
Correspondingly, the invention provides a curb based on composite reinforced recycled coarse aggregate, which comprises the composite reinforced recycled coarse aggregate, cement, fly ash, sand and a water reducing agent, wherein other auxiliary materials can be added according to concrete specific performance requirements;
specifically, 1100-1300 parts of composite reinforced recycled coarse aggregate, 300-400 parts of cement, 40-80 parts of fly ash, 600-750 parts of sand and 20-80 parts of water reducer;
wherein the sand is a mixture of machine-made sand and fine sand with good grading and fineness modulus of 2.3-2.7, and the mass ratio of the machine-made sand to the fine sand is 8:2, the grain size of the recycled coarse aggregate is 5-20 mm, the cement is ordinary Portland cement with the grade of P.O 42.5 or more, and the fly ash is fly ash with the grade of II or more.
As shown in fig. 2, the preparation method of the curb based on the composite reinforced recycled coarse aggregate specifically comprises the following steps:
(1) Preparing composite reinforced recycled coarse aggregate according to the batch reinforcing method of the recycled coarse aggregate;
(2) Stirring cement, fly ash, water and a water reducing agent to prepare cement paste;
(3) Adding the recycled coarse aggregate and stirring to fully mix the cement paste and the recycled aggregate;
(4) Adding sand, and fully stirring;
(5) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table for compaction, standing for 24 hours at room temperature, demoulding the obtained concrete curb, naturally sprinkling water for moisture maintenance of the demoulded concrete curb, and keeping the surface of the concrete moist;
the stirring sequence adopted is as follows: the cement paste is stirred with the recycled coarse aggregate and then stirred with sand. The stirring sequence can form a layer of cement shell on the surface of the recycled coarse aggregate, so that the interface strength of the recycled coarse aggregate and the mortar is enhanced, the interface damage probability of the concrete on the recycled coarse aggregate and the new cement mortar is reduced, and the overall strength is enhanced.
Wherein the sand is a mixture of machine-made sand and fine sand with good grading and fineness modulus of 2.3-2.7, and the mass ratio of the machine-made sand to the fine sand is 8:2, the grain size of the recycled coarse aggregate is 5-20 mm, the cement is ordinary Portland cement with the grade of P.O 42.5 or more, and the fly ash is fly ash with the grade of II or more.
The invention is illustrated below by means of specific examples:
example 1
A method for strengthening the recycled coarse aggregate of construction waste in batches comprises the following steps:
(1) Crushing and screening the cement concrete construction waste by adopting a jaw crusher to obtain recycled coarse aggregate with the grain size within the range of 5 mm-20 mm;
(2) Placing 200kg of the recycled coarse aggregate reserved after sieving into an abrasion tester each time, placing 1 steel ball per kg, wherein each steel ball has 415g, controlling the rotating speed of a roller to be 150r/min, and running for 10 minutes;
placing the crushed and ground coarse aggregate particles into a large abrasion tester, putting a proper amount of steel balls according to the requirement, passing the crushed and ground coarse aggregate particles through a square-hole sieve with the particle size of 4.75mm after running through a roller, and retaining the particles with the particle size of 5-20 mm in the sieve;
(3) Spreading the regenerated coarse aggregate particles obtained in the step (2) on a large screen, placing the screen in a calcium hydroxide solution with the concentration of 15g/L, and simultaneously introducing carbon dioxide gas into the solution, wherein the carbon dioxide gas rate is 1.5L/h, the soaking time of the regenerated coarse aggregate in the calcium hydroxide solution is 24h, and vibrating the screen for 15-30 min every 3 h;
(4) Placing the recycled coarse aggregate particles obtained after the carbonization treatment in the step (3) into a volcanic ash slurry pond for soaking, wherein the volcanic ash solution comprises cement and silica fume according to the mass ratio of 8:2, compounding and adding water, wherein the concentration of the volcanic ash solution is 15g/L, the soaking time is 4h, vibrating the screen for 15-20 min every 1h, and drying the soaked regenerated coarse aggregate particles to obtain the pretreated regenerated coarse aggregate;
(5) The pretreated recycled coarse aggregate particles are sprayed with pure acrylic polymer emulsion, the spraying amount is 4% of the mass of the recycled coarse aggregate particles, and the treated recycled coarse aggregate particles are dried to obtain the composite reinforced recycled coarse aggregate.
The composite reinforced recycled coarse aggregate particles, unreinforced recycled coarse aggregate particles and natural aggregate of example 1 were subjected to tests for crushing value, water absorption and apparent density by referring to the crushing index specified in GB/T14685, the apparent density test and the water absorption test specified in GB/T17431.2, and the results are shown in Table 1, wherein limestone crushed stones of 5 to 10mm and limestone crushed stone of 10 to 20mm were selected for the natural aggregate.
TABLE 1
| Apparent Density (g/cm) 3 ) | Crushing value (%) | Water absorption (%) | |
| Example 1 | 2.631 | 15.4 | 3.22 |
| Unreinforced coarse aggregate | 2.613 | 19.1 | 6.51 |
| Natural aggregate | 2.661 | 14.1 | 0.75 |
From the above table, it can be seen that the apparent density of the composite reinforced recycled coarse aggregate particles is increased, the crushing value is decreased, the water absorption is reduced, and the above-mentioned test index is close to that of the natural aggregate after the treatment by the recycling method of the present invention.
Example 2
A curb based on composite reinforced recycled coarse aggregate, comprising, in mass per unit volume: 690kg/m of sand 3 1150kg/m of composite reinforced recycled coarse aggregate 3 340kg/m of cement 3 40kg/m of fly ash 3 165kg/m of water 3 The water-gel ratio is 0.43; the mixing amount of the water reducer is 0.55% of the mass of the cementing material, wherein cement and fly ash are the cementing material.
The preparation method specifically comprises the following steps:
(1) Preparing reinforced construction waste recycled coarse aggregate according to the embodiment 1;
(2) Stirring 42.5-grade ordinary Portland cement, fly ash, water and a polycarboxylate water reducer for 60s to prepare cement paste;
(3) Adding the composite reinforced recycled coarse aggregate and stirring for 60s to fully mix the cement paste and the recycled aggregate
(4) Adding sand, and fully stirring for 120s;
(5) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table for compaction for 2-3 min, standing at room temperature for 24h, demoulding the obtained concrete curb, naturally sprinkling water for moisture maintenance of the demoulded concrete curb, wherein the maintenance time is not less than 7d, the environmental temperature is not less than 20 ℃ during the maintenance, and the surface of the concrete is kept moist.
Example 3
A curb based on composite reinforced recycled coarse aggregate, comprising, in mass per unit volume: 690kg/m of sand 3 1150kg/m of composite reinforced recycled coarse aggregate 3 340kg/m of cement 3 40kg/m of fly ash 3 165kg/m of water 3 The water-gel ratio is 0.43; the mixing amount of the water reducer is 0.55 percent (unit volume mass) of the cementing material, wherein cement and fly ash are the cementing material.
The preparation method specifically comprises the following steps:
(1) Preparing reinforced construction waste recycled coarse aggregate according to the embodiment 1;
(2) Stirring 42.5 grade ordinary Portland cement, fly ash, sand and composite reinforced regenerated coarse aggregate for 90s
(3) Adding water and a polycarboxylate water reducer, stirring for 120s to obtain a mixture;
(4) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table for compaction for 2-3 min, standing at room temperature for 24h, demoulding the obtained concrete curb, naturally sprinkling water for moisture maintenance of the demoulded concrete curb, wherein the maintenance time is not less than 7d, the environmental temperature is not less than 20 ℃ during the maintenance, and the surface of the concrete is kept moist.
Comparative example 1
The conventional common curb comprises the following raw materials in mass per unit volume: 690kg/m of sand 3 1150kg/m natural coarse aggregate 3 340kg/m of cement 3 40kg/m of fly ash 3 165kg/m of water 3 The water-gel ratio is 0.43; the mixing amount of the water reducer is 0.55% of the mass of the cementing material, wherein cement and fly ash are the cementing material, and the natural coarse aggregate is limestone gravels with the diameter of 5-10 mm and the diameter of 10-20 mm.
The conventional ordinary curb adopts a conventional stirring process, and the preparation method comprises the following steps:
(1) Stirring 42.5-grade ordinary Portland cement, fly ash, sand and natural coarse aggregate for 90s;
(2) Adding water and a polycarboxylate water reducer, and stirring for 120s to obtain a mixture;
(3) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table for compaction for 2-3 min, standing at room temperature for 24h, demoulding the obtained concrete curb, naturally sprinkling water for moisture maintenance of the demoulded concrete curb, wherein the maintenance time is not less than 7d, the environmental temperature is not less than 20 ℃ during the maintenance, and the surface of the concrete is kept moist.
Comparative example 2
The curb based on unreinforced recycled coarse aggregate comprises the following raw materials in terms of mass per unit volume: 690kg/m of sand 3 Unreinforced regenerated crude bone1150kg/m of granules 3 340kg/m of cement 3 40kg/m of fly ash 3 165kg/m of water 3 The water-gel ratio is 0.43; the mixing amount of the water reducer is 0.55 percent (unit volume mass) of the cementing material, wherein cement and fly ash are the cementing material.
The preparation method of the curb based on unreinforced recycled coarse aggregate adopts a conventional stirring process and comprises the following steps:
(1) Stirring 42.5 grade ordinary Portland cement, fly ash, sand and unreinforced recycled coarse aggregate particles for 90s;
(2) Adding water and a polycarboxylate water reducer, and stirring for 120s to obtain a mixture;
(3) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table for compaction for 2-3 min, standing at room temperature for 24h, demoulding the obtained concrete curb, naturally sprinkling water for moisture maintenance of the demoulded concrete curb, wherein the maintenance time is not less than 7d, the environmental temperature is not less than 20 ℃ during the maintenance, and the surface of the concrete is kept moist.
The curbs prepared in example 2, example 3, comparative example 1, comparative example 2 were tested for flexural strength, compressive strength, water absorption and frost resistance with reference to concrete curbs JC/T899-2016, and the results are shown in Table 2.
TABLE 2
As can be obtained from table 2, the basic performance index of the construction waste recycled coarse aggregate curb (example 2) provided by the invention is basically consistent with that of the curb prepared from natural aggregate (comparative example 1), compared with the conventional curb (comparative example 2) of unreinforced recycled aggregate and the conventional stirring process curb (example 3) of recycled aggregate after batched reinforcement, the building waste recycled coarse aggregate curb has obviously improved flexural strength and compressive strength, effectively reduced water absorption and freeze thawing quality loss rate, and provides a scene for the application of recycled coarse aggregate.
According to analysis, physical properties of the batched reinforced recycled coarse aggregate adopted by the embodiment of the invention are obviously improved compared with unreinforced recycled coarse aggregate particles, and then the cement slurry-wrapped stirring process is adopted to manufacture the curb, so that disadvantages of the recycled aggregate can be further avoided, and the road performance consistent with that of the natural conventional curb is finally realized.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The batch strengthening method for the recycled coarse aggregate is characterized by comprising the following steps of:
(1) Crushing and screening the cement concrete construction waste to obtain a recycled coarse aggregate raw material;
(2) Abrading the recycled coarse aggregate raw material, sieving the recycled coarse aggregate particles obtained after abrasion, retaining the particles in the sieve and washing with water;
(3) Immersing the recycled coarse aggregate particles in a calcium hydroxide solution, and uniformly introducing carbon dioxide gas into the solution to obtain the recycled coarse aggregate particles subjected to carbonization reaction;
(4) Uniformly immersing the regenerated coarse aggregate particles subjected to carbonization reaction into a volcanic ash slurry pond, and drying to obtain pretreated regenerated coarse aggregate particles;
(5) And spraying the pretreated recycled coarse aggregate particles with waterproof paint, and drying to obtain the composite reinforced recycled coarse aggregate.
2. The method for batch strengthening of recycled coarse aggregate according to claim 1, wherein in the step (1), the concrete construction waste is crushed to a particle size range of 5mm to 20mm by crushing a plurality of times.
3. The method for batch strengthening of recycled coarse aggregate according to claim 1, wherein in the step (2), the recycled coarse aggregate raw material is put into an abrasion tester for abrasion according to the specification of an abrasion instrument, the abraded recycled coarse aggregate particles are sieved by a square-hole sieve with the particle size of 4.75mm, and the particles with the particle size of 5mm to 20mm in the sieve are reserved.
4. The method for batch strengthening of recycled coarse aggregate according to claim 1, wherein in the step (3), the concentration of the calcium hydroxide solution is 10-20 g/L, the aeration rate of carbon dioxide is 1-1.5L/h, and the soaking time of the recycled coarse aggregate particles is 24h;
preferably, the concentration of the calcium hydroxide solution is 15g/L, the aeration rate of the carbon dioxide is 1.5L/h, and the soaking time of the regenerated coarse aggregate particles is 24h.
5. The method for batch strengthening of recycled coarse aggregate according to claim 1, wherein in the step (4), the concentration of the pozzolan solution is 15g/L and the soaking time is 4 hours.
6. The method for batch strengthening of recycled coarse aggregate according to claim 1, wherein in the step (5), the waterproof coating is pure acrylic polymer emulsion, and the spraying amount is 3-6% of the mass of the pretreated recycled coarse aggregate particles.
7. A composite reinforced recycled coarse aggregate prepared by the method for batch reinforcement of a recycled coarse aggregate according to any one of claims 1 to 6.
8. A curb based on the composite reinforced recycled coarse aggregate of claim 7, which comprises 1100-1300 parts of the composite reinforced recycled coarse aggregate, 300-400 parts of cement, 40-80 parts of fly ash, 600-750 parts of sand and 20-80 parts of water reducer.
9. The curb of claim 8, wherein the sand is a mixture of machine sand and fine sand, wherein the mass ratio of machine sand to fine sand is 8:2, the grain size of the regenerated coarse aggregate is 5-20 mm.
10. A method for preparing a kerb according to claim 8 or 9, characterized by the specific steps of:
(1) Preparing composite reinforced recycled coarse aggregate according to the batch reinforcing method of the recycled coarse aggregate;
(2) Stirring cement, fly ash, water and a water reducing agent to prepare cement paste;
(3) Adding the composite reinforced recycled coarse aggregate and stirring to fully mix the cement paste and the recycled aggregate;
(4) Adding sand, and fully stirring;
(5) Pouring the stirred mixture into a mould with a brushed release agent, vibrating on a vibrating table to be compact, standing for 24 hours at room temperature, demoulding the obtained concrete curb, naturally sprinkling water to maintain the demoulded concrete curb, and keeping the surface of the concrete moist.
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