CN117819924A - Nanometer ultra-high performance concrete and preparation method thereof - Google Patents
Nanometer ultra-high performance concrete and preparation method thereof Download PDFInfo
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- 239000011374 ultra-high-performance concrete Substances 0.000 title claims abstract description 109
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 239000002893 slag Substances 0.000 claims abstract description 85
- 239000000843 powder Substances 0.000 claims abstract description 71
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims abstract description 46
- 239000010881 fly ash Substances 0.000 claims abstract description 40
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000002994 raw material Substances 0.000 claims abstract description 32
- 239000003513 alkali Substances 0.000 claims abstract description 26
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 25
- 150000001875 compounds Chemical class 0.000 claims abstract description 25
- 229910000019 calcium carbonate Inorganic materials 0.000 claims abstract description 23
- 239000011325 microbead Substances 0.000 claims abstract description 23
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 22
- 239000000835 fiber Substances 0.000 claims abstract description 22
- 239000010959 steel Substances 0.000 claims abstract description 22
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000011398 Portland cement Substances 0.000 claims abstract description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 51
- 230000000694 effects Effects 0.000 claims description 40
- 239000000203 mixture Substances 0.000 claims description 35
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 34
- 239000004568 cement Substances 0.000 claims description 33
- 239000012190 activator Substances 0.000 claims description 29
- 239000002245 particle Substances 0.000 claims description 26
- 238000002156 mixing Methods 0.000 claims description 24
- 238000003756 stirring Methods 0.000 claims description 21
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 16
- 239000000243 solution Substances 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 8
- 229920005646 polycarboxylate Polymers 0.000 claims description 8
- 239000002699 waste material Substances 0.000 claims description 7
- 238000012423 maintenance Methods 0.000 claims description 5
- 239000003469 silicate cement Substances 0.000 claims description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 239000006004 Quartz sand Substances 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- 239000004576 sand Substances 0.000 claims description 2
- 230000000052 comparative effect Effects 0.000 description 33
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 16
- 230000004907 flux Effects 0.000 description 16
- 238000005452 bending Methods 0.000 description 13
- 239000001569 carbon dioxide Substances 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
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- 238000009472 formulation Methods 0.000 description 4
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- 238000012360 testing method Methods 0.000 description 4
- 230000036571 hydration Effects 0.000 description 3
- 238000006703 hydration reaction Methods 0.000 description 3
- 239000002986 polymer concrete Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
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- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- -1 aluminosilicate compound Chemical class 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
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- 239000013078 crystal Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
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- 229910021487 silica fume Inorganic materials 0.000 description 1
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- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention belongs to the technical field of ultra-high performance concrete, and particularly relates to nano ultra-high performance concrete and a preparation method thereof. One of the purposes is to provide the nano ultra-high performance concrete, which comprises the following raw materials in parts by weight: 150-400 parts of general Portland cement; 200-450 parts of slag powder; 100-150 parts of fly ash modified microbeads; 50-100 parts of metakaolin; 22-50 parts of a compound alkali excitant; 7-15 parts of nano calcium carbonate; 800-1200 parts of fine aggregate; 10-26 parts of water reducer; 40-90 parts of steel fiber; wherein the water-gel ratio of the nano ultra-high performance concrete is 0.15-0.27. The invention also aims to provide a preparation method of the nano ultra-high performance concrete.
Description
Technical Field
The invention belongs to the technical field of ultra-high performance concrete, and particularly relates to nano ultra-high performance concrete and a preparation method thereof.
Background
The geopolymer concrete prepared by alkali-activated materials (such as silica fume, fly ash, slag powder and the like) rich in two elements of silicon and aluminum is used as a novel non-cement-based cementing material, is an inorganic aluminosilicate compound with ceramic-like characteristics, does not need high-temperature maintenance, has the advantages of low production energy consumption, low carbon dioxide emission, low cost, high utilization rate of industrial solid wastes, good durability and the like, but also has the defects of short setting and hardening time, poor working performance, high brittleness and the like, and does not meet the increasingly higher requirements of construction technology.
Ultra-high performance concrete (UHPC) is designed based on the theory of close packing of raw materials, and the ultra-fine auxiliary cementing material is doped and the dosage of the high-efficiency water reducer is increased, so that the ultra-high performance concrete (UHPC) has low water-gel ratio and high system compactness, and shows excellent mechanical properties and durability. However, UHPC production uses Portland cement up to 700-1100kg/m 3 Higher than ordinary concreteAnd 2-3 times, silicate cement consumes a great amount of natural resources and energy sources in the production process. According to the research, a skilled production of one ton consumes 6.6 megajoules of energy, and simultaneously discharges 0.82 ton of carbon dioxide, greatly increasing economic cost and environmental burden, which is quite disadvantageous for sustainable development of economy.
Aiming at the problems, the design principle of the two is combined, the low-carbon environment-friendly ultra-high-performance concrete is developed, the effective compromise between the material performance index and the green low-carbon requirement is realized, the new requirement of the high-performance civil engineering material is met, and the method has outstanding practical significance.
Disclosure of Invention
The invention aims to overcome at least one defect of the prior art, and aims to provide nano ultra-high performance concrete and a preparation method thereof, which are used for solving the problems of natural resources, high energy consumption and high carbon emission in the preparation process of the ultra-high performance concrete.
The technical scheme adopted by the invention is that the nano ultra-high performance concrete comprises the following raw materials in parts by weight:
150-400 parts of general Portland cement;
200-450 parts of slag powder;
100-150 parts of fly ash modified microbeads;
50-100 parts of metakaolin;
22-50 parts of a compound alkali excitant;
7-15 parts of nano calcium carbonate;
800-1200 parts of fine aggregate;
10-26 parts of water reducer;
40-90 parts of steel fiber;
the water-gel ratio of the nano ultra-high performance concrete is 0.15-0.27.
According to the invention, by adding the universal silicate cement with the proportion, the early hydration speed and the hydration heat are reduced, and the setting time of the mixture is prolonged; adjusting the early strength and the early mix hardening rate to achieve adjustment of setting time; by adding the nano calcium carbonate in the proportion, on one hand, the nano calcium carbonate plays a role of crystal nucleus and promotes cement hydration and alkali excitation reaction; on the other hand, the filling effect is achieved, so that the nano ultra-high performance concrete is more compact, and the mechanical property and the durability are improved. By adding the water reducer with the proportion, the water reducer has the functions of dispersing, lubricating, steric hindrance and slow release of graft copolymerization branched chains, and the fluidity and slump retention of the mixture are improved. By adding the composite alkali excitant in the proportion, the initial setting time of the ultra-high-performance concrete can be shortened, and the ultra-high-performance concrete has high early strength. By adding the modified fly ash microbeads in the proportion, on one hand, the modified fly ash microbeads participate in alkali excitation reaction, so that the hardening strength is improved; on the other hand, the lubricating effect is achieved, and the fluidity of the mixture is improved. Compared with the ultra-high-performance concrete prepared by silicate cement, the ultra-high-performance concrete provided by the invention has the advantages that the carbon dioxide emission is reduced by more than 50% under the condition of the same cubic number, the utilization rate of industrial solid waste is high, the cost is low, the manufacturing is simple, the high-temperature maintenance is not needed, the compressive strength is high, the durability is good, meanwhile, the ultra-high-performance concrete also has the excellent characteristics of long setting time, good toughness and the like, and can meet the requirements of actual use on reliability and structural strength and the social requirements of low carbon and environmental protection.
The water-cement ratio is the ratio of the water consumption of concrete per cubic meter to the consumption of all cementing materials, the weight of the cementing materials in the invention is the sum of the weights of cement, slag powder, fly ash modified microbeads and metakaolin, and water meeting the requirements is added based on the water-cement ratio, so that the high-performance nano ultra-high-performance concrete is prepared.
The invention further provides a preparation method of the nano ultra-high performance concrete, which comprises the following steps:
preparing a compound alkali excitant into a solution, and standing for a preset time; obtaining the nano ultra-high performance concrete raw materials with corresponding parts by weight, and uniformly stirring and mixing according to a preset sequence to obtain a nano ultra-high performance concrete mixture; and pouring the nano ultra-high performance concrete mixture in a mould to obtain the nano ultra-high performance concrete.
Compared with the prior art, the invention has the beneficial effects that: 1) Compared with the ultra-high performance concrete prepared by silicate cement, the nano ultra-high performance concrete provided by the invention has the advantages that the carbon dioxide emission is reduced by more than 50% under the same cubic number condition, the utilization rate of industrial solid waste is high, the cost is low, the preparation is simple, the high-temperature maintenance is not needed, the compressive strength reaches 130-200 MPa, and the durability is good; 2) Compared with the traditional polymer concrete, the nano ultra-high performance concrete provided by the invention has the characteristics of good working performance, long setting time, good toughness and the like.
Drawings
FIG. 1 is a flow chart of a process for preparing the nano ultra-high performance concrete of the present invention in some embodiments.
Detailed Description
The invention aims to provide nano ultra-high performance concrete, which comprises the following raw materials in parts by weight:
150-400 parts of general Portland cement;
200-450 parts of slag powder;
100-150 parts of fly ash modified microbeads;
50-100 parts of metakaolin;
22-50 parts of a compound alkali excitant;
7-15 parts of nano calcium carbonate;
800-1200 parts of fine aggregate;
10-26 parts of water reducer;
40-90 parts of steel fiber;
the water-gel ratio of the nano ultra-high performance concrete is 0.15-0.27.
Based on the composition and the proportion of the formula, the prepared nano ultra-high performance concrete has excellent performances in various aspects such as expansion degree, compressive strength, bending toughness ratio, electric flux and the like, greatly reduces carbon dioxide emission and meets the green environment-friendly requirement.
In a preferred embodiment, the nano ultra-high performance concrete comprises the following raw materials in parts by weight:
212.5 to 337.5 portions of general Portland cement;
262.5 to 387.5 portions of slag powder;
112.5 to 137.5 portions of fly ash modified microbeads;
62.5 to 87.5 portions of metakaolin;
29-43 parts of a compound alkali excitant;
9-13 parts of nano calcium carbonate;
900-1100 parts of fine aggregate;
14-22 parts of water reducer;
52.5 to 77.5 portions of steel fiber;
the water-gel ratio of the nano ultra-high performance concrete is 0.18-0.24.
Based on the preferable formula, the properties of the nano ultra-high performance concrete in various aspects such as compression resistance, durability, toughness and the like can be further improved.
In some embodiments, the universal portland cement is specifically any one or a mixture of two of slag cement and fly ash cement. The fly ash cement is formed by processing fly ash and common clinker as raw materials, the fly ash is industrial waste, the consumption is large, the fly ash cement can be recycled, the raw material cost is saved, the environment-friendly requirement is met, in addition, the fly ash cement has uniform texture and stable quality, and the construction is convenient. The slag cement is prepared by mixing cement clinker and slag, wherein the slag is waste from metallurgical industry, and the consumption is large, thereby being beneficial to saving the raw material cost and meeting the green environment-friendly requirement.
In the preferred embodiment, the strength of the slag cement and the fly ash cement is not lower than 32.5Mpa, so that the prepared nano ultra-high-performance concrete has higher strength.
To further improve the performance, in a preferred embodiment, the slag powder has an average particle size of 5 to 30 μm; and/or the average particle size of the fly ash modified microbeads is 5-30 μm; and/or the average particle size of the metakaolin is 5-30 mu m; and/or the average particle diameter of the fine aggregate is 0.15-4.755 mm; and/or the water reducer is specifically a polycarboxylate water reducer; and/or the length-diameter ratio of the steel fiber is 60-120.
In some embodiments, the slag powder comprises the following raw materials in percentage by weight: the slag powder with the activity index of 75 percent is 10 to 30 percent, the slag powder with the activity index of 95 percent is 30 to 70 percent, and the slag powder with the activity index of 105 percent is 0 to 60 percent, so that the compressive strength and the bending toughness ratio of the prepared nano ultra-high performance concrete can be greatly improved, good expansion degree and smaller electric flux can be ensured, and the overall performance is improved.
In a preferred embodiment, the slag powder comprises the following raw materials in percentage by weight: the slag powder with the activity index of 75 percent is 15-25 percent, the slag powder with the activity index of 95 percent is 40-60 percent, and the slag powder with the activity index of 105 percent is 15-45 percent, and the compressive strength, the expansion degree, the bending toughness ratio, the electric flux and other properties of the nano ultra-high performance concrete can be further improved by adopting the slag powder with the formula proportion.
In some embodiments, the fine aggregate is one or more of river sand, quartz sand, waste ceramic aggregate and waste glass aggregate.
In a preferred embodiment, the waste ceramic aggregate has a water absorption of less than 3%.
In some embodiments, the complex alkali-activator is a mixture of sodium hydroxide and sodium carbonate.
In a preferred embodiment, the composite alkali-activator comprises the following raw materials in percentage by weight: the composite alkali excitant with the formula has 50-80% of sodium hydroxide and 20-50% of sodium carbonate, so that the prepared nano ultra-high performance concrete has better expansion degree, compressive strength and bending toughness ratio, smaller electric flux and better overall performance.
More preferably, the compound alkali-activator comprises the following raw materials in percentage by weight: the composite alkali activator with the formula ratio can further improve the expansion degree, compressive strength, bending toughness ratio, electric flux and other properties of the nano ultra-high performance concrete by 60-70% of sodium hydroxide and 30-40% of sodium carbonate.
The invention further aims to provide a preparation method of the nano ultra-high performance concrete, which comprises the following steps: preparing a compound alkali excitant into a solution, and standing for a preset time; obtaining the nano ultra-high performance concrete raw materials with corresponding parts by weight, and uniformly stirring and mixing according to a preset sequence to obtain a nano ultra-high performance concrete mixture; and pouring the nano ultra-high performance concrete mixture in a mould to obtain the nano ultra-high performance concrete.
Wherein, because the compound alkali excitant needs to be placed for a preset time after being prepared into solution, in order to better connect each procedure, in some embodiments, the step can be processed in advance, and then each raw material of the nano ultra-high performance concrete is uniformly mixed.
In other embodiments, in consideration of the fact that a certain time is required for the mixing process of the raw materials of the nano ultra-high performance concrete, the solution of the composite alkali-activator may be prepared and placed for a preset time as required during the mixing process of the raw materials of the nano ultra-high performance concrete.
Wherein the preset time may be 8-48 hours, and in some embodiments, the preset time is 24 hours.
In some embodiments, the stirring and mixing in the preset order is as follows: firstly, stirring and mixing fine aggregate and steel fibers, then adding general Portland cement, slag powder, fly ash modified microbeads, metakaolin and nano calcium carbonate, stirring and mixing, and finally adding alkali-activator solution, water and water reducer, stirring and mixing.
In the preferred embodiment, the time for stirring and mixing the fine aggregate and the steel fiber is 2-4 minutes, and/or the time for stirring and mixing the fine aggregate and the steel fiber after adding the common Portland cement, the slag powder, the fly ash modified microbeads, the metakaolin and the nano calcium carbonate is 4-6 minutes, and/or the time for stirring and mixing the fine aggregate and the steel fiber after adding the alkali-activator solution, the water and the water reducer is 5-8 minutes, and/or the expansion degree of the nano ultra-high performance concrete mixture is 500-750 mm, and/or the setting time of the nano ultra-high performance concrete mixture is 2-6 hours.
In some embodiments, the compressive strength of the nano ultra-high performance concrete obtained after the nano ultra-high performance concrete is subjected to normal temperature moisture maintenance for 28 days is 130-200 MPa.
In some embodiments, the preparation method of the nano ultra-high performance concrete is as shown in fig. 1, and comprises the following steps:
s1, preparing a compound alkali excitant into a solution, and standing for 24 hours for later use;
s2, calculating the consumption of each raw material according to the part ratio of the nano ultra-high performance concrete, and uniformly stirring and mixing the fine aggregate and the steel fiber; then adding slag cement and/or fly ash cement, slag powder, fly ash modified microbeads, metakaolin and nano calcium carbonate, and stirring and uniformly mixing; finally adding the alkali-activator solution, water and the water reducer, and stirring and uniformly mixing to prepare the nano ultra-high performance concrete mixture;
s3, pouring the nano ultra-high performance concrete mixture prepared in the step S2 in a mould to obtain the nano ultra-high performance concrete.
Preferably, the fine aggregate and the steel fiber are stirred and mixed for 2 to 4 minutes.
Preferably, slag cement and/or fly ash cement are added, and the slag powder, the fly ash modified microbeads, the metakaolin and the nano calcium carbonate are stirred and mixed for 4-6 minutes.
Preferably, the alkali-activated agent solution, water and the water reducer are added and stirred for uniform mixing for 5-8 minutes.
Based on the control of the mixing time, the method can ensure sufficient mixing, avoid consuming too much stirring time and shorten the preparation period of the nano ultra-high performance concrete.
In a preferred embodiment, the expansion degree of the prepared nano ultra-high performance concrete mixture is 500-750 mm.
In addition, setting the setting time of the nano ultra-high performance concrete mixture in the step S2 to be 2-6 hours ensures that the nano ultra-high performance concrete with the performance meeting the requirements can be prepared in the next working procedure.
In a preferred embodiment, in the step S3, the compressive strength of the nano ultra-high performance concrete obtained in the step of maintaining at normal temperature for 28 days is 130-200 MPa.
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and apparatus used, without any particular description, are those conventional in the art and are commercially available to those skilled in the art.
Example 1
The embodiment provides a nano ultra-high performance concrete, which comprises the following raw materials in parts by weight:
slag cement with strength not lower than 32.5MPa and/or fly ash cement with strength not lower than 32.5MPa in total 150 parts;
200 parts of slag powder with an average particle size of 5-30 mu m, wherein the slag powder with an activity index of 75% is 10%, the slag powder with an activity index of 95% is 30%, and the slag powder with an activity index of 105% is 60%;
100 parts of fly ash modified microbeads with an average particle size of 5-30 mu m;
50 parts of metakaolin with an average particle size of 5-30 mu m;
22 parts of a composite alkali activator, wherein the mass percent of sodium hydroxide is 50% and the mass percent of sodium carbonate is 50%;
7 parts of nano calcium carbonate;
800 parts of fine aggregate with the average particle size of 0.15-4.755 mm;
10 parts of polycarboxylate water reducer;
40 parts of steel fiber with the length-diameter ratio of 60-120;
the water-gel ratio is 0.15.
The preparation method of the nano ultra-high performance concrete is prepared according to the following steps:
s11, preparing a compound alkali excitant into a solution, and standing for 24 hours for later use;
s21, calculating the consumption of each raw material according to the mixing ratio of the nano ultra-high performance concrete, and putting the fine aggregate and the steel fibers into a stirrer to stir for 2-4 minutes; then adding slag cement and/or fly ash cement, slag powder, fly ash modified microbeads, metakaolin and nano calcium carbonate, and stirring for 4-6 minutes; finally adding the alkali-activator solution, water and the polycarboxylate water reducer, and stirring for 5-8 minutes to obtain the nano ultra-high performance concrete mixture;
s31, pouring the nano ultra-high performance concrete mixture obtained in the step S21 in a mould to obtain the nano ultra-high performance concrete.
Example 2
This example is the same as example 1 except that the formulation of the nano ultra-high performance concrete is different.
The nano ultra-high performance concrete provided by the embodiment comprises the following raw materials in parts by weight:
400 parts of slag cement with the strength of not lower than 32.5MPa and/or fly ash cement with the strength of not lower than 32.5MPa;
450 parts of slag powder with the average particle size of 5-30 mu m, wherein the slag powder with the activity index of 75% is 30%, the slag powder with the activity index of 95% is 70%, and the slag powder with the activity index of 105% is 0%;
50 parts of fly ash modified microbeads with an average particle size of 5-30 mu m;
100 parts of metakaolin with an average particle size of 5-30 mu m;
50 parts of a compound alkali excitant, wherein the mass percent of sodium hydroxide is 80 percent, and the mass percent of sodium carbonate is 20 percent;
15 parts of nano calcium carbonate;
1200 parts of fine aggregate with the average grain diameter of 0.15-4.755 mm;
26 parts of polycarboxylate water reducer;
90 parts of steel fiber with the length-diameter ratio of 60-120;
the water-gel ratio is 0.27.
Example 3
This example is the same as example 1 except that the formulation of the nano ultra-high performance concrete is different.
The nano ultra-high performance concrete provided by the embodiment comprises the following raw materials in parts by weight:
212.5 parts of slag cement with the strength of not less than 32.5MPa and/or fly ash cement with the strength of not less than 32.5MPa;
262.5 parts of slag powder with the average particle size of 5-30 mu m, wherein the slag powder with the activity index of 75% is 15%, the slag powder with the activity index of 95% is 40%, and the slag powder with the activity index of 105% is 45%;
112.5 parts of fly ash modified microbeads with the average particle size of 5-30 mu m;
62.5 parts of metakaolin with the average particle size of 5-30 mu m;
29 parts of a compound alkali-activated agent, wherein the mass percent of sodium hydroxide is 60% and the mass percent of sodium carbonate is 40%;
9 parts of nano calcium carbonate;
900 parts of fine aggregate with the average particle size of 0.15-4.755 mm;
14 parts of polycarboxylate water reducer;
52.5 parts of steel fiber with the length-diameter ratio of 60-120;
the water-gel ratio is 0.18.
Example 4
This example is the same as example 1 except that the formulation of the nano ultra-high performance concrete is different.
The nano ultra-high performance concrete provided by the embodiment comprises the following raw materials in parts by weight:
337.5 parts of slag cement with the strength of not less than 32.5MPa and/or fly ash cement with the strength of not less than 32.5MPa;
387.5 parts of slag powder with the average particle size of 5-30 mu m, wherein the slag powder with the activity index of 75% is 25%, the slag powder with the activity index of 95% is 60%, and the slag powder with the activity index of 105% is 15%;
137.5 parts of fly ash modified microbeads with the average particle size of 5-30 mu m;
87.5 parts of metakaolin with the average particle size of 5-30 mu m;
43 parts of a compound alkali excitant, wherein the mass percent of sodium hydroxide is 70 percent, and the mass percent of sodium carbonate is 30 percent;
13 parts of nano calcium carbonate;
fine aggregate with average grain size of 0.15-4.755 mm accounting for 1100 parts;
22 parts of polycarboxylate water reducer;
77.5 parts of steel fiber with the length-diameter ratio of 60-120;
the water-gel ratio is 0.24.
Example 5
This example is the same as example 1 except that the formulation of the nano ultra-high performance concrete is different.
The nano ultra-high performance concrete provided by the embodiment comprises the following raw materials in parts by weight:
275 parts of slag cement with the strength of not less than 32.5MPa and/or fly ash cement with the strength of not less than 32.5MPa;
325 parts of slag powder with the average particle size of 5-30 mu m, wherein the slag powder with the activity index of 75 percent is 20 percent, the slag powder with the activity index of 95 percent is 50 percent and the slag powder with the activity index of 105 percent is 30 percent;
125 parts of fly ash modified microbeads with the average particle size of 5-30 mu m;
75 parts of metakaolin with an average particle size of 5-30 mu m;
36 parts of composite alkali activator, wherein the mass percent of sodium hydroxide is 65 percent, and the mass percent of sodium carbonate is 35 percent;
11 parts of nano calcium carbonate;
1000 parts of fine aggregate with the average grain diameter of 0.15-4.755 mm;
18 parts of polycarboxylate water reducer;
65 parts of steel fiber with the length-diameter ratio of 60-120;
the water-gel ratio is 0.21.
Comparative example 1
The comparative example is different in that the addition part of the compound alkali-activator is 10 parts, and other conditions are the same as in example 1, wherein the formula of the compound alkali-activator of the comparative example is also the same as in example 1, namely 50% by mass of sodium hydroxide and 50% by mass of sodium carbonate.
Comparative example 2
The comparative example is different in that the added part of nano calcium carbonate is 3 parts, and the other conditions are the same as in example 1.
Comparative example 3
The comparative example is different in that the addition part of the compound alkali-activator is 60 parts, and other conditions are the same as in example 1, wherein the formula of the compound alkali-activator of the comparative example is also the same as in example 1, namely 50% by mass of sodium hydroxide and 50% by mass of sodium carbonate.
Comparative example 4
The added parts of the compound alkali-activator of this comparative example were kept 22 parts as in example 1, except that the compound alkali-activator was formulated as follows: the mass percent of sodium hydroxide was 30%, the mass percent of sodium carbonate was 70%, and the other conditions were the same as in example 1.
Comparative example 5
The added parts of the compound alkali-activator of this comparative example were kept 22 parts as in example 1, except that the compound alkali-activator was formulated as follows: the mass percent of sodium hydroxide was 90%, the mass percent of sodium carbonate was 10%, and the other conditions were the same as in example 1.
Comparative example 6
The comparative example also had 200 parts of slag powder having an average particle diameter of 5 to 30. Mu.m, and only the specific composition of the slag powder was different, wherein the conditions were the same as in example 1 except that the slag powder had an activity index of 75% of 60%, an activity index of 95% of 20% and an activity index of 105% of 20%.
Comparative example 7
The comparative example also had 200 parts of slag powder having an average particle diameter of 5 to 30. Mu.m, and only the specific composition of the slag powder was different, wherein the conditions were the same as in example 1 except that the slag powder having an activity index of 75% was 5%, the slag powder having an activity index of 95% was 90%, and the slag powder having an activity index of 105% was 5%.
Comparative example 8
The comparative example is a C150 ultra-high performance concrete prepared using Portland cement, wherein 700kg of Portland cement is used for one cubic C150 ultra-high performance concrete.
Comparative example 9
This comparative example is a conventional polymer concrete.
Test case
The nano ultra-high performance concrete prepared in examples 1 to 5 and comparative examples 1 to 7 and the C150 ultra-high performance concrete of comparative example 8, the uniform geopolymer concrete of comparative example 9 were tested for expansion degree, setting time, compressive strength, electric flux and flexural toughness ratio, and the carbon dioxide emissions of comparative examples 1 and 6 were compared, and experimental data are shown in table 1.
Table 1 ultra high performance concrete test data
Based on the test results of table 1, it can be seen that:
in comparative example 1, only the addition amount of the composite alkali-activator is lower than that of example 1, and compared with example 1, the prepared nano ultra-high performance concrete has slightly reduced expansion degree and setting time, more reduction of compressive strength and bending toughness ratio and more increase of electric flux.
In comparative example 2, only the addition amount of nano calcium carbonate is lower than that of example 1, and the prepared nano ultra-high performance concrete has basically consistent expansion degree, slightly reduced setting time, more reduction of compression strength and bending toughness ratio and more increase of electric flux compared with that of example 1.
In comparative example 3, only the additive amount of the composite alkali-activator is higher than that of example 1, and compared with example 1, the prepared nano ultra-high performance concrete has more reduction in expansion degree, setting time, compressive strength and bending toughness ratio and more increase in electric flux.
In comparative example 4, the amount of the composite alkali-activator added was 22 parts, and the composition of the composite alkali-activator was different from that of example 1, wherein the mass percentage of sodium hydroxide was 30% and the mass percentage of sodium carbonate was 70%, and the obtained nano ultra-high performance concrete was compared with example 1, and the expansion degree, compressive strength and flexural toughness were more reduced, the setting time was slightly reduced, and the electric flux was more increased.
In comparative example 5, the amount of the composite alkali-activator added was 22 parts, and the composition of the composite alkali-activator was different from that of example 1, wherein the mass percent of sodium hydroxide was 90% and the mass percent of sodium carbonate was 10%, and the prepared nano ultra-high performance concrete was more reduced in expansion degree, setting time, bending toughness ratio and compressive strength and more increased in electric flux than that of example 1.
In comparative example 6, only the composition of the slag powder was different, specifically, 60% of the slag powder having an activity index of 75%, 20% of the slag powder having an activity index of 95%, and 20% of the slag powder having an activity index of 105%, and the expansion degree and the setting time were slightly decreased, and the compression strength and the bending toughness were more decreased and the electric flux was more increased, compared with example 1.
In comparative example 7, the composition of the slag powder was also different, specifically, 75% of the slag powder having an activity index of 5%, 95% of the slag powder having an activity index of 90%, and 105% of the slag powder having an activity index of 5%, and the degree of expansion and the setting time were slightly decreased, and the compression strength and the flexural toughness were more decreased and the electric flux was more increased, as compared with example 1.
In comparative example 8, the C150 ultra-high performance concrete prepared by using Portland cement has a larger cement consumption, and the expansion degree, the setting time, the compressive strength, the bending toughness ratio and the electric flux are basically consistent, so that the carbon dioxide emission is increased more and about 125 percent compared with those of the embodiment 1.
In comparative example 9, using conventional polymer concrete, the expansion degree, setting time and bending toughness ratio were more reduced, the compressive strength was slightly reduced, and the electric flux was more increased, compared with example 1.
Based on the test, the selected raw materials such as the composite alkali excitant, the slag powder, the nano calcium carbonate and the like are optimal; the nano ultra-high performance concrete can obviously reduce the carbon dioxide emission, improve the utilization rate of industrial solid wastes, and also has advantages in a plurality of main technical indexes such as expansion degree, compressive strength, bending toughness, electric flux and the like.
It should be understood that the foregoing examples of the present invention are merely illustrative of the present invention and are not intended to limit the present invention to the specific embodiments thereof. Any modification, equivalent replacement, improvement, etc. that comes within the spirit and principle of the claims of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. The nano ultra-high performance concrete is characterized by comprising the following raw materials in parts by weight:
150-400 parts of general Portland cement;
200-450 parts of slag powder;
100-150 parts of fly ash modified microbeads;
50-100 parts of metakaolin;
22-50 parts of a compound alkali excitant;
7-15 parts of nano calcium carbonate;
800-1200 parts of fine aggregate;
10-26 parts of water reducer;
40-90 parts of steel fiber;
the water-gel ratio of the nano ultra-high performance concrete is 0.15-0.27.
2. The nano ultra-high performance concrete according to claim 1, which is characterized by comprising the following raw materials in parts by weight:
212.5 to 337.5 portions of general Portland cement;
262.5 to 387.5 portions of slag powder;
112.5 to 137.5 portions of fly ash modified microbeads;
62.5 to 87.5 portions of metakaolin;
29-43 parts of a compound alkali excitant;
9-13 parts of nano calcium carbonate;
900-1100 parts of fine aggregate;
14-22 parts of water reducer;
52.5 to 77.5 portions of steel fiber;
the water-gel ratio of the nano ultra-high performance concrete is 0.18-0.24.
3. The nano ultra-high performance concrete according to claim 1 or 2, wherein the general Portland cement is any one or a mixture of two of slag cement and fly ash cement; and/or the strength of the general Portland cement is not lower than 32.5Mpa; and/or the average grain size of the slag powder is 5-30 mu m; and/or the average particle size of the fly ash modified microbeads is 5-30 mu m; and/or, the average particle size of the metakaolin is 5-30 μm; and/or the fine aggregate has an average particle diameter of 0.15 to 4.755mm; and/or the water reducer is a polycarboxylate water reducer; and/or the length-diameter ratio of the steel fiber is 60-120.
4. The nano ultra-high performance concrete according to claim 1 or 2, wherein the slag powder comprises the following raw materials in percentage by weight: 10-30% of slag powder with an activity index of 75%, 30-70% of slag powder with an activity index of 95%, and 0-60% of slag powder with an activity index of 105%; preferably, the slag powder comprises the following raw materials in percentage by weight: 15-25% of slag powder with an activity index of 75%, 40-60% of slag powder with an activity index of 95% and 15-45% of slag powder with an activity index of 105%.
5. The nano ultra-high performance concrete according to claim 1 or 2, wherein the fine aggregate is one or more of river sand, quartz sand, waste ceramic aggregate and waste glass aggregate; preferably, the waste ceramic aggregate has a water absorption of less than 3%.
6. The nano ultra-high performance concrete according to claim 1 or 2, wherein the composite alkali activator is a mixture of sodium hydroxide and sodium carbonate.
7. The nano ultra-high performance concrete of claim 6, wherein the composite alkali-activator comprises the following raw materials in percentage by weight: 50-80% of sodium hydroxide and 20-50% of sodium carbonate; preferably, the compound alkali-activator comprises the following raw materials in percentage by weight: 60-70% of sodium hydroxide and 30-40% of sodium carbonate.
8. A method for preparing nano ultra-high performance concrete according to any one of claim 1 to 7, wherein,
preparing a compound alkali excitant into a solution, and standing for a preset time; obtaining the nano ultra-high performance concrete raw materials with corresponding parts by weight, and uniformly stirring and mixing according to a preset sequence to obtain a nano ultra-high performance concrete mixture; and pouring the nano ultra-high performance concrete mixture in a mould to obtain the nano ultra-high performance concrete.
9. The preparation method according to claim 8, wherein the stirring and mixing are performed in a preset order: firstly, stirring and mixing fine aggregate and steel fibers uniformly, then adding general Portland cement, slag powder, fly ash modified microbeads, metakaolin and nano calcium carbonate, stirring and mixing uniformly, and finally adding alkali-activator solution, water and water reducer, stirring and mixing uniformly;
preferably, the fine aggregate and the steel fiber are stirred and mixed for 2-4 minutes, and/or the common silicate cement, slag powder, fly ash modified microbeads, metakaolin and nano calcium carbonate are added and stirred and mixed for 4-6 minutes, and/or the alkali-exciting agent solution, water and water reducing agent are added and stirred and mixed for 5-8 minutes, and/or the expansion degree of the nano ultra-high performance concrete mixture is 500-750 mm, and/or the setting time of the nano ultra-high performance concrete mixture is 2-6 hours.
10. The preparation method of claim 8, wherein the prepared nano ultra-high performance concrete has a compressive strength of 130-200 MPa after being subjected to normal-temperature moisture maintenance for 28 days.
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