CN113788666A - Super early strength recycled concrete and preparation method thereof - Google Patents
Super early strength recycled concrete and preparation method thereof Download PDFInfo
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- CN113788666A CN113788666A CN202111185042.3A CN202111185042A CN113788666A CN 113788666 A CN113788666 A CN 113788666A CN 202111185042 A CN202111185042 A CN 202111185042A CN 113788666 A CN113788666 A CN 113788666A
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- 239000004567 concrete Substances 0.000 title claims abstract description 83
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910021487 silica fume Inorganic materials 0.000 claims abstract description 13
- 239000000654 additive Substances 0.000 claims abstract description 12
- 230000000996 additive effect Effects 0.000 claims abstract description 12
- 229940050906 magnesium chloride hexahydrate Drugs 0.000 claims abstract description 6
- DHRRIBDTHFBPNG-UHFFFAOYSA-L magnesium dichloride hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-] DHRRIBDTHFBPNG-UHFFFAOYSA-L 0.000 claims abstract description 6
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 32
- 238000002156 mixing Methods 0.000 claims description 21
- 239000010419 fine particle Substances 0.000 claims description 19
- 229960002337 magnesium chloride Drugs 0.000 claims description 16
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 7
- 239000011777 magnesium Substances 0.000 claims description 7
- 229910052749 magnesium Inorganic materials 0.000 claims description 7
- 229940091250 magnesium supplement Drugs 0.000 claims description 7
- 238000005728 strengthening Methods 0.000 claims description 7
- 239000004568 cement Substances 0.000 claims description 6
- FPAFDBFIGPHWGO-UHFFFAOYSA-N dioxosilane;oxomagnesium;hydrate Chemical compound O.[Mg]=O.[Mg]=O.[Mg]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O FPAFDBFIGPHWGO-UHFFFAOYSA-N 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 5
- 238000010521 absorption reaction Methods 0.000 claims description 4
- 239000000395 magnesium oxide Substances 0.000 claims description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 4
- WRUGWIBCXHJTDG-UHFFFAOYSA-L magnesium sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Mg+2].[O-]S([O-])(=O)=O WRUGWIBCXHJTDG-UHFFFAOYSA-L 0.000 claims description 4
- 229940061634 magnesium sulfate heptahydrate Drugs 0.000 claims description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 4
- 239000002002 slurry Substances 0.000 claims description 4
- CENHPXAQKISCGD-UHFFFAOYSA-N trioxathietane 4,4-dioxide Chemical compound O=S1(=O)OOO1 CENHPXAQKISCGD-UHFFFAOYSA-N 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 230000003014 reinforcing effect Effects 0.000 claims description 3
- 239000002893 slag Substances 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 2
- 229920002401 polyacrylamide Polymers 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 230000000979 retarding effect Effects 0.000 claims description 2
- 229920000247 superabsorbent polymer Polymers 0.000 claims description 2
- 229920002774 Maltodextrin Polymers 0.000 claims 1
- 239000005913 Maltodextrin Substances 0.000 claims 1
- 229940035034 maltodextrin Drugs 0.000 claims 1
- 239000011398 Portland cement Substances 0.000 abstract description 3
- 239000004566 building material Substances 0.000 abstract description 2
- 239000002994 raw material Substances 0.000 abstract description 2
- 238000011161 development Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- GXCLVBGFBYZDAG-UHFFFAOYSA-N N-[2-(1H-indol-3-yl)ethyl]-N-methylprop-2-en-1-amine Chemical group CN(CCC1=CNC2=C1C=CC=C2)CC=C GXCLVBGFBYZDAG-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- IQYKECCCHDLEPX-UHFFFAOYSA-N chloro hypochlorite;magnesium Chemical compound [Mg].ClOCl IQYKECCCHDLEPX-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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
- 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
- C04B28/30—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 magnesium cements or similar 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
- C04B14/042—Magnesium silicates, e.g. talc, sepiolite
-
- 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
- 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
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
-
- 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
- C04B2111/20—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
- 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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention belongs to the technical field of building materials, and discloses super early strength recycled concrete and a preparation method thereof, wherein the recycled concrete is prepared from the following raw materials in parts by weight: comprises the following components in parts by mass: 170-190 parts of water, 140-155 parts of light-burned magnesium powder, 20-40 parts of silica fume, 100-120 parts of magnesium chloride hexahydrate, 400-500 parts of natural aggregate, 1400-1520 parts of reinforced recycled aggregate and 6-10 parts of additive. The 3d compressive strength of the super early strength recycled concrete can reach more than 70% of the 28d compressive strength, and the 7d compressive strength can reach 90% of the 28d compressive strength; and the 28-day compressive strength is close to that of common portland cement concrete, so that the engineering requirements can be completely met, the recycled concrete can be utilized to the maximum extent, the resources are saved, and the environment is protected.
Description
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to recycled aggregate prepared by utilizing residual concrete in a concrete mixer truck tank.
Background
At present, the demand of global concrete increases with the acceleration and daily increase of economic development and urbanization progress, and the problems are that a large amount of natural aggregate is consumed and a large amount of construction waste is generated due to the removal of concrete with expired service life. The regenerated aggregate concrete, called regenerated concrete for short, is a new concrete prepared by crushing, cleaning and grading waste concrete blocks to prepare regenerated aggregate, mixing the regenerated aggregate with the graded aggregate according to a certain proportion and partially or completely replacing natural aggregate, and can effectively realize the recycling of resources.
The national patent (CN 113354369A) discloses a high-strength recycled concrete and a preparation method thereof, wherein the recycled coarse aggregate is prepared by soaking crushed waste concrete in mineral slurry and drying; the mineral slurry is composed of the following raw materials in parts by weight: 70-80 parts of slag powder, 20-30 parts of silica fume, 10-15 parts of graphene oxide and 600 parts of water. The high-strength recycled concrete has the advantages of high compressive strength and good impermeability.
The national patent (CN 113354344A) discloses a recycled concrete and a preparation method thereof, and the recycled concrete comprises the following components in parts by mass: 40-50 parts of recycled coarse aggregate, 20-30 parts of fine aggregate, 2-4 parts of water reducing agent, 3-6 parts of talcum powder, 15-20 parts of cement and 8-10 parts of water. The strength of the recycled concrete can be improved, and the water absorption rate can be reduced.
But the regenerated concrete still has the defects of slow strength development and the like, and because the porosity of the regenerated aggregate is large, a plurality of cracks are generated, and the interface transition area is complex, a new strength development supporting structure is difficult to form. In summary, how to design a recycled concrete, the strength development is fast so as to adapt to the fast forming scene of the concrete, which is a problem to be solved urgently at present.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides super early strength recycled aggregate concrete and a preparation method thereof.
Comprises the following components in percentage by mass: 170-190 parts of water, 140-155 parts of light-burned magnesium powder, 20-40 parts of silica fume, 100-120 parts of magnesium sulfate heptahydrate, 400-500 parts of natural aggregate, 1400-1520 parts of reinforced recycled aggregate and 6-10 parts of additive.
The additive is an early strength agent.
The preparation method of the super early strength recycled concrete is characterized by comprising the following steps:
step one, preparing recycled coarse aggregate, and pretreating concrete fine particles;
step two, preparing a magnesium chloride solution, mixing the concrete fine particles pretreated in the step one with natural aggregate and reinforced recycled aggregate, and mixing light-burned magnesium powder with silica fume;
and step three, uniformly mixing the material obtained in the step two with a magnesium chloride solution, adding an additive, uniformly stirring, and hardening to obtain the super early strength recycled concrete.
The concrete fine particle pretreatment in the first step comprises the following steps:
A. screening the concrete fine particles to obtain fine materials of 0-3 mm;
B. and (3) uniformly mixing the fine material with the thickness of 0-3 mm obtained in the step A with talcum powder, and screening again to obtain the pretreated fine material, wherein the mass ratio of the concrete fine particles to the talcum powder is 1: 2-1: 3.
The preparation method of the reinforced recycled aggregate in the second step comprises the following steps:
1) crushing and screening the recycled aggregate by using a jaw crusher, and collecting the crushed residual concrete fine particles for later use;
2) preparing a magnesium chloride solution by using magnesium sulfate heptahydrate, adding light-burned magnesium powder, mixing to obtain magnesium oxysulfate cement slurry, adding a high water absorption polymer and a slow-setting component, and preparing into a strengthening solution;
3) immersing the recycled aggregate into the strengthening liquid for 1h, wherein the mass ratio of the recycled aggregate to the strengthening liquid is 1: 3-1: 4, taking out the recycled aggregate to dry, removing broken slag by using mechanical vibration for 3h, carrying out steam curing for 3h at the temperature of 60 ℃ and the relative humidity of 80%, taking out and drying.
The recycled aggregate in the step 1) is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 5-40 mm.
In the step 2), the content of magnesium oxide in the light-burned magnesium powder is 80 percent, and the content of active magnesium oxide is 60 percent;
n (MgSO) in step 2)4) N (MgO) is 5:1 to 10: 1.
In the step 2), the super absorbent polymer is polyacrylamide resin, and the retarding component is malt paste.
The concentration of the strengthening liquid in the step 2) is 20-30%.
In the second step, the magnesium chloride hexahydrate contains magnesium chloride more than 45%, the concentration of the magnesium chloride solution is 20-25%, and n (MgO) and n (MgCl)2) The ratio of the pretreated concrete fine material to the natural aggregate is 7: 1-8: 1, and the pretreated concrete fine material with equal mass is used for replacing the natural aggregate.
The invention discloses super early strength recycled concrete and a preparation method thereof, and the super early strength recycled concrete has the following advantages:
(1) the recycled aggregate is reinforced by the magnesium oxysulfate cement reinforcing liquid, and the magnesium oxysulfate cement paste can form a layer of coating material on the surface of the aggregate, so that the wear resistance and the mechanical property of the recycled aggregate are improved, the water absorption is reduced, and the properties of the recycled aggregate are close to those of a natural aggregate.
(2) The talcum powder is used for pretreating concrete fine particles and equivalently replaces natural aggregate, so that the utilization rate of broken concrete is improved, certain contribution is made to the fluidity of recycled concrete, and the cost is reduced.
(3) The magnesium oxychloride cement is used for mixing the recycled concrete and is doped with the silica fume and the early strength agent for modification, so that the water resistance of the recycled concrete is improved while the mechanical property and the mechanical property are ensured, the setting time of the recycled concrete is greatly reduced, the strength development rate is improved, and the method is particularly suitable for soft soil foundation reinforcement engineering with high requirement on construction speed.
Detailed Description
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Examples
Example 1 ultra-early-strength recycled concrete and preparation method thereof
170 parts of water, 140 parts of light-burned magnesium powder, 20 parts of silica fume, 100 parts of magnesium chloride hexahydrate, 400 parts of natural aggregate, 1400 parts of reinforced recycled aggregate and 6 parts of additive.
(1) Preparing recycled coarse aggregate, and pretreating concrete fine particles;
(2) preparing a magnesium chloride solution, mixing the concrete fine particles pretreated in the step one with natural aggregate and reinforced recycled aggregate, and mixing light-burned magnesium and silica fume;
(3) and (4) uniformly mixing the material obtained in the step two with a magnesium chloride solution, adding an additive, uniformly stirring, and hardening to obtain the super early strength recycled concrete.
Example 2 ultra-early-strength recycled concrete and preparation method thereof
190 parts of water, 155 parts of light-burned magnesium powder, 40 parts of silica fume, 20 parts of magnesium chloride hexahydrate, 500 parts of natural aggregate, 520 parts of reinforced recycled aggregate and 10 parts of additive.
(1) Preparing recycled coarse aggregate, and pretreating concrete fine particles;
(2) preparing a magnesium chloride solution, mixing the concrete fine particles pretreated in the step one with natural aggregate and reinforced recycled aggregate, and mixing light-burned magnesium and silica fume;
(3) and (4) uniformly mixing the material obtained in the step two with a magnesium chloride solution, adding an additive, uniformly stirring, and hardening to obtain the super early strength recycled concrete.
Example 3 ultra-early-strength recycled concrete and preparation method thereof
180 parts of water, 150 parts of light-burned magnesium powder, 30 parts of silica fume, 110 parts of magnesium chloride hexahydrate, 450 parts of natural aggregate, 1470 part of reinforced recycled aggregate and 8 parts of additive.
(1) Preparing recycled coarse aggregate, and pretreating concrete fine particles;
(2) preparing a magnesium chloride solution, mixing the concrete fine particles pretreated in the step one with natural aggregate and reinforced recycled aggregate, and mixing light-burned magnesium and silica fume;
(3) and (4) uniformly mixing the material obtained in the step two with a magnesium chloride solution, adding an additive, uniformly stirring, and hardening to obtain the super early strength recycled concrete.
Comparative examples 1 to 3 used the same composition ratios as in examples 1 to 3, and natural coarse aggregate was used instead of the reinforcing recycled aggregate and ordinary portland cement was used to prepare concrete.
The recycled concrete prepared in the embodiments 1-3 and the recycled concrete prepared in the comparative examples 1-3 are subjected to mechanical property detection by referring to GB/T50081-2019 standard of common concrete mechanical property test method, and the compressive strength of 3d and 7d are respectively measured, and the detection results are shown in Table 1.
TABLE 1 results of mechanical Properties measurements
| 3d compressive Strength (MPa) | 7d compressive Strength (MPa) | 28d compressive Strength (MPa) | |
| Example 1 | 49.2 | 57.4 | 61.3 |
| Example 2 | 47.8 | 57.1 | 59.5 |
| Example 3 | 46.3 | 58.5 | 62.6 |
| Comparative example 1 | 29.1 | 45.9 | 65.7 |
| Comparative example 2 | 30.1 | 47.4 | 68.2 |
| Comparative example 3 | 29.5 | 46.2 | 66.9 |
As can be seen from Table 1, compared with the prior art, the technical scheme of the invention can greatly improve the rate of the development of the setting and the strength, the 3d compressive strength of the embodiment can reach more than 70% of the 28d compressive strength, and the 7d compressive strength can reach 90% of the 28d compressive strength; and the 28-day compressive strength is close to that of common portland cement concrete, so that the engineering requirements can be completely met, the recycled concrete can be utilized to the maximum extent, the resources are saved, and the environment is protected.
It is to be understood that the foregoing is only illustrative of the preferred embodiments of the present invention and that no limitation to the scope of the invention is thereby intended, such alterations and modifications being within the spirit and scope of the invention.
Claims (10)
1. The super early strength recycled concrete is characterized by comprising the following components in percentage by mass: 170-190 parts of water, 140-155 parts of light-burned magnesium powder, 20-40 parts of silica fume, 100-120 parts of magnesium sulfate heptahydrate, 400-500 parts of natural aggregate, 1400-1520 parts of reinforced recycled aggregate and 6-10 parts of additive.
2. The ultra-early strength recycled concrete of claim 1, wherein said admixture is an early strength agent.
3. The preparation method of the super early strength recycled concrete is characterized by comprising the following steps:
step one, preparing recycled coarse aggregate, and pretreating concrete fine particles;
step two, preparing a magnesium chloride solution, mixing the concrete fine particles pretreated in the step one with natural aggregate and reinforced recycled aggregate, and mixing light-burned magnesium powder with silica fume;
and step three, uniformly mixing the material obtained in the step two with a magnesium chloride solution, adding an additive, uniformly stirring, and hardening to obtain the super early strength recycled concrete.
4. The method for preparing ultra-early-strength recycled concrete according to claim 3, wherein the concrete fine particle pretreatment in the first step comprises the following steps:
screening the concrete fine particles to obtain fine materials of 0-3 mm;
and (3) uniformly mixing the fine material with the thickness of 0-3 mm obtained in the step A with talcum powder, and screening again to obtain the pretreated fine material, wherein the mass ratio of the concrete fine particles to the talcum powder is 1: 2-1: 3.
5. The method for preparing the ultra-early-strength recycled concrete according to claim 3, wherein the method for preparing the reinforced recycled aggregate in the second step comprises the following steps:
crushing and screening the recycled aggregate by using a jaw crusher, and collecting the crushed residual concrete fine particles for later use;
preparing a magnesium chloride solution by using magnesium sulfate heptahydrate, adding light-burned magnesium powder, mixing to obtain magnesium oxysulfate cement slurry, adding a high water absorption polymer and a slow-setting component, and preparing into a strengthening solution;
immersing the recycled aggregate into the strengthening liquid for 1h, wherein the mass ratio of the recycled aggregate to the strengthening liquid is 1: 3-1: 4, taking out the recycled aggregate to dry, removing broken slag by using mechanical vibration for 3h, carrying out steam curing for 3h at the temperature of 60 ℃ and the relative humidity of 80%, taking out and drying.
6. The preparation method of the ultra-early-strength recycled concrete according to claim 5, wherein the recycled aggregate in the step 1) is recycled coarse aggregate obtained by crushing and grading recycled concrete, and the particle size range is 5-40 mm.
7. The method for preparing the ultra-early-strength recycled concrete according to claim 5, wherein in the step 2), the content of magnesium oxide in the light-burned magnesium powder is 80%, and the content of active magnesium oxide is 60%;
the method for preparing super early strength recycled concrete according to claim 5, wherein n (MgSO) in step 2)4) N (MgO) is 5:1 to 10: 1.
8. The method for preparing super early strength recycled concrete according to claim 5, wherein the super absorbent polymer in step 2) is polyacrylamide resin, and the retarding component is maltodextrin.
9. The method for preparing the ultra-early-strength recycled concrete according to claim 5, wherein the concentration of the reinforcing liquid in the step 2) is 20-30%.
10. The method for preparing super early strength recycled concrete according to claim 3, wherein in the second step, the content of magnesium chloride in the magnesium chloride hexahydrate is more than 45%, the concentration of the magnesium chloride solution is 20-25%, and n (MgO) to n (MgCl)2) The ratio of the pretreated concrete fine material to the natural aggregate is 7: 1-8: 1, and the pretreated concrete fine material with equal mass is used for replacing the natural aggregate.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115403316A (en) * | 2022-09-26 | 2022-11-29 | 陕西建科建筑加固工程有限公司 | Environment-friendly early-strength concrete for foundation reinforcement and preparation method thereof |
| CN115677252A (en) * | 2022-11-07 | 2023-02-03 | 江苏科技大学 | Method for improving water resistance of magnesium oxychloride cement recycled aggregate concrete |
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Application publication date: 20211214 |