CN108640635B - Coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate and preparation method thereof - Google Patents

Coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate and preparation method thereof Download PDF

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CN108640635B
CN108640635B CN201810595089.9A CN201810595089A CN108640635B CN 108640635 B CN108640635 B CN 108640635B CN 201810595089 A CN201810595089 A CN 201810595089A CN 108640635 B CN108640635 B CN 108640635B
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recycled concrete
concrete aggregate
magnesium
oxysulfate cement
cinder powder
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CN108640635A (en
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张立明
李佳
张智越
朱志
于国新
张轩图
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Nanchang Institute of Technology
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Nanchang Institute of Technology
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/30Compositions 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
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength

Abstract

The invention discloses a stable recycled concrete aggregate of coal cinder powder magnesium oxysulfate cement, which comprises the following components in percentage by mass, which are uniformly mixed: 93 to 97 percent of recycled concrete aggregate, 1.56 to 3.12 percent of magnesium oxide, 0.57 to 1.90 percent of coal slag powder, 0.76 to 1.80 percent of magnesium sulfate and 0.09 to 0.18 percent of water-resistant additive. The invention also discloses a preparation method of the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement. The stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement has the characteristics of convenient material taking, energy conservation and environmental protection, and is a novel building material; the method greatly utilizes solid wastes such as waste concrete, coal slag, bischofite and the like, can solve the problems of environmental protection and land occupation caused by the waste concrete and the coal slag, relieves increasingly deficient sandstone and cement resources, expands the application range of the magnesium oxysulfate cement, and has profound influence and wide application prospect; and the unconfined compressive strength meets the standard requirement, and the construction progress can be accelerated.

Description

Coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate and preparation method thereof
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to a stable recycled concrete aggregate of coal cinder powder magnesium oxysulfate cement and a preparation method thereof.
Background
Every year, construction of infrastructure in China needs hundreds of millions of tons of sandstone materials, so that 'white hanging of a green mountain and yellow river water' are caused, the environment of China is seriously influenced, meanwhile, sandstone resources are non-renewable, and in order to protect the environment and limited sandstone resources, other materials are urgently needed to replace the sandstone resources. Meanwhile, hundreds of millions of tons of waste concrete are stacked in the open air every year in China, so that the environment is polluted, and a large amount of land resources are occupied; therefore, the recycling of the waste concrete becomes the key research point in China, so as to effectively relieve the pressure of the shortage of natural aggregates and the problem of environmental pollution caused by concrete wastes.
Hundreds of millions of tons of coal slag are stacked in the open air in China, only part of the coal slag is used for making bricks, paving and cement mixing materials at present, but the utilization rate of the coal slag is low; therefore, it is highly desirable to improve the utilization rate and the utilization value thereof.
Meanwhile, China has abundant magnesium sulfate resources, the reserve of magnesium sulfate resources in salt lake brine is about 16.73 trillion tons, and the reserve of magnesium sulfate in seawater reaches 3570 trillion tons. Generally, the magnesium sulfate is obtained by natural crystallization of brine obtained by extracting bromine and potassium from seawater.
In conclusion, how to recycle the waste concrete and coal slag and how to search for a substitute of sandstone materials becomes a technical problem to be solved urgently.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides the following technical scheme:
the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement comprises the following components in percentage by mass which are uniformly mixed:
furthermore, the recycled concrete aggregate is obtained by crushing, removing ribs, sorting, screening, cleaning and drying waste concrete aggregate.
Furthermore, the recycled concrete aggregate is composed of 5-20% of rice sand with the grain diameter of 0.075-5 mm by mass, 25-35% of sunflower seed slices with the grain diameter of 5-13 mm by mass, 25-40% of small fragments with the grain diameter of 13-25 mm by mass and 5-20% of medium fragments with the grain diameter of 25-40 mm by mass.
Further, the coal slag powder is obtained by crushing, drying and grinding coal slag and then sieving the crushed, dried and ground coal slag through a 45-micrometer negative pressure sieve.
Further, the magnesium oxide is light magnesium oxide powder with the purity of not less than 80%, and the specific surface area of the magnesium oxide is 2.1m2/kg~2.3m2/kg。
Further, the magnesium sulfate is magnesium sulfate monohydrate and/or magnesium sulfate heptahydrate.
Further, the water-resistant additive is a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate in a mass ratio of 1:3: 1.
Further, the three-day unconfined compressive strength of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate is at least 5.6MPa, and the seven-day unconfined compressive strength is at least 6.5 MPa.
The invention also aims to provide a preparation method of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, which comprises the following steps of:
further, the preparation method also comprises the step of adding water into the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate for mixing; wherein the mass of the water is 9.68-12.7% of that of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate.
The invention has the beneficial effects that:
(1) the invention discovers that: crushing the waste concrete into recycled concrete aggregate with the performance meeting the standard requirement; therefore, the recycled concrete aggregate is used for replacing common natural materials in the prior art, the pressure of natural aggregate shortage and the problem of environmental pollution caused by concrete waste can be effectively relieved, and the recycled concrete aggregate recycled concrete aggregate recycled aggregate concrete aggregate is one of effective measures for ensuring the sustainable development of the society;
(2) the invention discovers that: crushing, drying and grinding the coal cinder for 45min, and then sieving the coal cinder through a negative pressure sieve of 45 mu m to obtain coal cinder powder, wherein the volcanic ash activity of the obtained coal cinder powder is superior to that of the second-level fly ash; therefore, the invention uses the coal cinder powder to replace mineral admixture in the prior art, can solve the problems of coal cinder occupying area and environmental pollution, improves the utilization value of the coal cinder, and can relieve the current situation of mineral admixture shortage;
(3) the magnesium oxysulfate cement is formed by magnesium sulfate and magnesium oxide in a specific ratio, so that the energy conservation and emission reduction are realized, the problem of magnesium harm in a salt lake region can be solved, the yield of potash fertilizers is improved, cultivated land is saved, and the application range of the magnesium oxysulfate cement is expanded;
(4) the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement has the characteristics of convenient material taking, energy conservation and environmental protection, and is a novel building material; the material can greatly utilize solid wastes such as waste concrete, coal slag, bischofite and the like, can solve the problems of environmental protection and land occupation caused by the waste concrete and the coal slag, relieves increasingly deficient sandstone and cement resources, and enlarges the application range of the magnesium oxysulfate cement, and has profound influence and wide application prospect;
(5) practical engineering proves that the unconfined compressive strength of the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement meets the standard requirement, and the construction progress can be accelerated.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail. This invention may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application to thereby enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated.
The invention provides a stable recycled concrete aggregate of coal cinder powder magnesium oxysulfate cement, which comprises the following components in percentage by mass, which are uniformly mixed:
specifically, the recycled concrete aggregate is obtained by crushing, removing ribs, sorting, screening, washing and drying waste concrete aggregate, and has the composition shown in table 1.
TABLE 1 composition of recycled concrete aggregates
It should be noted that when determining the specific composition of the recycled concrete aggregate, the optimum ratio is selected according to the molding method (compaction or vibration) test and the requirement of unconfined compressive strength of the final or coal cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate.
Further, the waste concrete aggregate comprises one or more of waste concrete such as excavated concrete panels, waste building or bridge members, concrete test blocks and members; the recycled concrete aggregate of the invention is required to have a crushing value of not more than 30% according to the grading requirement of technical Specification for construction of road pavements and bases (JTJ 034-2000).
More specifically, the coal cinder powder is obtained by crushing, drying and grinding coal cinder and then sieving the crushed, dried and ground coal cinder through a 45-micrometer negative pressure sieve; the magnesium oxide is light magnesium oxide powder with purity not less than 80%, and its specific surface area is 2.1m2/kg~2.3m2Per kg; the magnesium sulfate can be industrial magnesium sulfate and/or bischofite; and the water-resistant additive is a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate with the mass ratio of 1:3:1, namely the AK type composite water-resistant agent in the Aladdin reagent factory.
The three-day unconfined compressive strength of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate provided by the invention is at least 5.6MPa, and the seven-day unconfined compressive strength is at least 6.5 MPa; when no engineering test is carried out, the corresponding performance of twenty-eight days is generally required to be measured, the twenty-eight days unconfined compressive strength of the test is at least 8.2MPa, and the test meets the requirement of the highway use function.
The preparation method of the stable recycled concrete aggregate of coal cinder powder magnesium oxysulfate cement provided by the invention is simple in process and easy to prepare, and only the components with the mass contents are required to be uniformly mixed.
It will be understood by those skilled in the art that, in the case of cement concrete products, which may be either in the form of a dry powder (block) as described above or in the form of a mixture with water, the relevant properties of the cement concrete product can generally be determined only after mixing with water; therefore, when the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement is mixed with water, magnesium oxide, magnesium sulfate and a water-resistant additive can form the magnesium oxysulfate cement, and the stable recycled concrete aggregate shows more excellent performance compared with the traditional portland cement. Meanwhile, for the magnesium oxysulfate cement, the mixing water dosage (namely the relative dosage of water and magnesium oxide and/or magnesium sulfate, commonly called water-cement ratio) has great influence on the performance of the final product; for this reason, it is generally determined by vibration test that water with a mass of 9.68% to 12.7% of the mass of the cinder powder magnesium oxychloride cement stabilized recycled concrete aggregate is preferably added to the cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate to be mixed so as to show excellent use effect.
The above-mentioned cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate of the present invention, its preparation method and application properties will be illustrated below by specific examples, but those skilled in the art will understand that the following examples are only specific examples of the present invention, and are different from the technical solutions limiting the whole thereof.
Example 1
First, recycled concrete aggregate was produced as follows.
Specifically, waste cement concrete road slabs, members for demolishing buildings, waste cement concrete test blocks and the like are collected and recovered; sequentially carrying out primary crushing, rib removing and secondary crushing on the recycled waste concrete, and screening to obtain recycled concrete aggregate with the required particle size range; the mass percentages of the obtained recycled concrete aggregates passing through the following mesh openings are shown in table 2.
TABLE 2 content of recycled concrete aggregates passing through each sieve mesh
Pressing of the resulting recycled concrete aggregateThe crushing value is 22.6 percent, and the apparent density is 2.69g/cm3
The results of the screening in table 2 above were mixed in a mass ratio of 33.4% of rice sand, 29.2% of melon seed pieces, 23.5% of small crumbs and 13.9% of medium crumbs to obtain recycled concrete aggregates.
Then, the coal cinder powder having the index listed in Table 3 was used.
TABLE 3 coal cinder powder index
And finally, mixing the components according to the mass ratio of the magnesium oxide to the coal slag powder to the magnesium sulfate to the water-resistant additive to the recycled concrete aggregate of 1.56:0.57:0.78:0.09: 97.
In this embodiment, the water-resistant additive is a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate in a mass ratio of 1:3: 1; the magnesium oxide is light magnesium oxide powder with purity not less than 80%, and its specific surface area is 2.1m2/kg~2.3m2Per kg; the magnesium sulfate is industrial magnesium sulfate.
In order to verify the service performance of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, 9.68 percent of tap water in mass of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate is added into the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate for mixing according to the maximum dry density and the optimal water content determined by a vibration test, and the unconfined compressive strengths of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate in 3d, 7d and 28d ages are respectively determined to be 5.85MPa, 6.67MPa and 8.22 MPa.
Example 2
First, recycled concrete aggregate was produced as follows.
Specifically, waste cement concrete road slabs, members for demolishing buildings, waste cement concrete test blocks and the like are collected and recovered; sequentially carrying out primary crushing, rib removing and secondary crushing on the recycled waste concrete, and screening to obtain recycled concrete aggregate with the required particle size range; the mass percentages of the obtained recycled concrete aggregates passing through the following mesh openings are shown in table 4.
TABLE 4 content of recycled concrete aggregates passing through each sieve mesh
The obtained recycled concrete aggregate had a crush value of 24.6% and an apparent density of 2.72g/cm3
The results of the screening in table 4 above were mixed in a mass ratio of 35.6% rice sand, 18.7% melon seed pieces, 25.6% small crumbs, and 20.1% medium crumbs to obtain recycled concrete aggregate.
Then, the coal cinder powder and the magnesium oxide with indexes listed in table 3 in example 1 are mixed with the water-resistant additive and the recycled concrete aggregate according to the same mass ratio as that in example 1.
In the embodiment, the water-resistant additive is a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate in a mass ratio of 1:3: 1; the magnesium oxide is light magnesium oxide powder with purity not less than 80%, and its specific surface area is 2.1m2/kg~2.3m2Per kg; magnesium sulfate is bischofite.
In order to verify the service performance of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, 10.16 percent of tap water in mass of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate is added into the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate for mixing according to the maximum dry density and the optimal water content determined by a vibration test, and the unconfined compressive strengths of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate in 3d, 7d and 28d ages are respectively measured to be 5.63MPa, 6.53MPa and 8.34 MPa.
Example 3
In the description of embodiment 3, the same points as those of embodiment 1 will not be described again, and only the differences from embodiment 1 will be described. Example 3 is different from example 1 in that magnesium oxide, coal slag powder, magnesium sulfate, a water-resistant additive and recycled concrete aggregate are mixed according to the mass ratio of 2.08:0.76:1.04:0.12: 96; the stable recycled concrete aggregate of the cinder powder magnesium oxysulfate cement of the present example was obtained as described in the rest of reference example 1.
The same measurement method as that in example 1 was adopted to measure the service performance of the stable recycled concrete aggregate of cinder powder magnesium oxysulfate cement in this example. The maximum dry density and the optimum water content determined by a vibration test are added with tap water accounting for 10.68 percent of the mass of the cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, and the unconfined compressive strengths of the concrete aggregate in 3d, 7d and 28d ages are respectively measured to be 6.24MPa, 7.13MPa and 8.84 MPa.
Example 4
In the description of embodiment 4, the same points as those of embodiment 2 will not be described again, and only the differences from embodiment 2 will be described. Example 4 is different from example 2 in that magnesium oxide, coal slag powder, magnesium sulfate, a water-resistant additive, and recycled concrete aggregate are mixed according to a mass ratio of 2.6:0.95:1.30:0.15: 95; the stable recycled concrete aggregate of the cinder powder magnesium oxysulfate cement of the present example was obtained as described in the rest of reference example 2.
The same measurement method as that in example 2 was adopted to measure the service performance of the stable recycled concrete aggregate of cinder powder magnesium oxysulfate cement in this example. Maximum dry density (2.04 g/cm) determined by vibration test3) And the optimal water content (10.8 percent), 11.16 percent of tap water of the mass of the cinder powder magnesium oxysulfate cement stable recycled concrete aggregate is added into the mixture for mixing, and the unconfined compressive strengths of the concrete aggregate in 3d, 7d and 28d ages are respectively measured to be 7.58MPa, 8.21MPa and 9.16 MPa.
Example 5
In the description of embodiment 5, the same points as those of embodiment 2 will not be described again, and only the differences from embodiment 2 will be described. The difference between the embodiment 5 and the embodiment 2 is that the magnesium oxide, the coal slag powder, the magnesium sulfate, the water-resistant additive and the recycled concrete aggregate are mixed according to the mass ratio of 2.80:1.22:1.80:0.18: 94; the stable recycled concrete aggregate of the cinder powder magnesium oxysulfate cement of the present example was obtained as described in the rest of reference example 2.
The same measurement method as that in example 2 was adopted to measure the service performance of the stable recycled concrete aggregate of cinder powder magnesium oxysulfate cement in this example. The maximum dry density and the optimum water content determined by a vibration test are added with tap water accounting for 11.78 percent of the mass of the cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, and the unconfined compressive strengths of the concrete aggregate in 3d, 7d and 28d ages are respectively measured to be 8.86MPa, 9.64MPa and 10.83 MPa.
Example 6
In the description of embodiment 6, the same points as those of embodiment 2 will not be described again, and only the differences from embodiment 2 will be described. Example 6 differs from example 2 in that the substances are mixed in a mass ratio of magnesium oxide, coal slag powder, magnesium sulfate, water-resistant additive, recycled concrete aggregate of 1.85:1.90:1.10:0.15: 95; the stable recycled concrete aggregate of the cinder powder magnesium oxysulfate cement of the present example was obtained as described in the rest of reference example 2.
The same measurement method as that in example 2 was adopted to measure the service performance of the stable recycled concrete aggregate of cinder powder magnesium oxysulfate cement in this example. The maximum dry density and the optimal water content determined by vibration tests are added with tap water accounting for 11.54 percent of the mass of the cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate, and the unconfined compressive strengths of the concrete aggregate in 3d, 7d and 28d ages are respectively measured to be 5.84MPa, 7.18MPa and 8.68 MPa.
Example 7
The embodiment is an engineering test, and the design standard is a second-level road.
This example also processed a waste cement concrete panel according to the process described in example 1 to obtain recycled concrete aggregate; the mass percentages of the obtained recycled concrete aggregates passing through the following mesh openings are shown in table 5.
TABLE 5 content of recycled concrete aggregates passing through each sieve mesh
The obtained recycled concrete aggregate had a crush value of 20.8% and an apparent density of 2.54g/cm3
The screening results in table 5 above were mixed by mass ratio of 40% rice sand, 29% melon seed pieces, 10% small crumbs, 21% medium crumbs to obtain recycled concrete aggregate.
Magnesium sulfate, magnesium oxide and coal slag powder (SiO)2、Al2O3、Fe2O3The total mass percent of the coal cinder powder, the sulfur oxide and magnesium cement and the weight loss of the burnt slag are not less than 70 percent) and not less than 10 percent.
In the engineering test, the coal cinder powder magnesium oxysulfate cement recycled concrete aggregate adopts the following two groups of mixture ratios:
group 1: mixing the components according to the mass ratio of magnesium oxide, coal slag powder, magnesium sulfate, a water-resistant additive (a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate with the mass ratio of 1:3: 1) and the recycled concrete aggregate of 1.56:1.56:0.76:0.12: 96; the maximum dry density of the mixture is 2.03g/cm through vibration molding3Adding tap water with the optimal water content of 11.9 percent, wherein the tap water accounts for 12.6 percent of the mass of the coal cinder powder, the magnesium oxysulfate and the cement stable recycled concrete aggregate, and mixing; the unconfined compressive strength of the test pieces 3d and 7d in age is respectively 5.71MPa and 6.69MPa, and the actually measured deflection value of the test section is 9 multiplied by 10-2mm~16×10-2mm(BZZ-100)。
Group 2: mixing the components according to the mass ratio of magnesium oxide, coal slag powder, magnesium sulfate, a water-resistant additive (a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate with the mass ratio of 1:3: 1) and the recycled concrete aggregate of 1.95:1.90:1.00:0.15: 95; the maximum dry density of the mixture is 2.07g/cm through vibration molding3Adding tap water with the optimal water content of 12.1 percent, wherein the tap water accounts for 12.6 percent of the mass of the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate, and mixing; the unconfined compressive strength of the test pieces 3d and 7d in age is 6.54MPa and 8.31MPa respectively, and the actually measured deflection value of the test section is 7 multiplied by 10-2mm~15×10-2mm(BZZ-100)。
While the invention has been shown and described with reference to certain embodiments, those skilled in the art will understand that: various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims (8)

1. The coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate is characterized by comprising the following components in parts by mass which are uniformly mixed:
93% -97% of recycled concrete aggregate;
1.56% -3.12% of magnesium oxide;
0.57-1.90% of coal slag powder;
0.76% -1.80% of magnesium sulfate;
0.09% -0.18% of water-resistant additive;
the water-resistant additive is a mixture of sodium dihydrogen phosphate, aluminum sulfate and iron phosphate in a mass ratio of 1:3: 1;
the recycled concrete aggregate is composed of 5-20% by mass of rice sand with the particle size of 0.075 mm-5 mm, 25-35% by mass of melon seed pieces with the particle size of 5 mm-13 mm, 25-40% by mass of small pieces with the particle size of 13 mm-25 mm and 5-20% by mass of medium pieces with the particle size of 25 mm-40 mm.
2. The coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate of claim 1, wherein the recycled concrete aggregate is obtained by crushing, removing ribs, sorting, screening, cleaning and drying waste concrete aggregates.
3. The coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate of claim 1, wherein the coal cinder powder is obtained by crushing, drying and grinding coal cinder and then sieving the crushed, dried and ground coal cinder powder with a 45 μm negative pressure sieve.
4. The coal cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate of claim 1, wherein the magnesium oxide is light magnesium oxide powder with a purity of not less than 80%, and the specific surface area of the magnesium oxide is 2.1m2/kg~2.3 m2/kg。
5. The cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate of claim 1, wherein the magnesium sulfate is magnesium sulfate monohydrate and/or magnesium sulfate heptahydrate.
6. The cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate of any one of claims 1 to 5, wherein the cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate has a three-day unconfined compressive strength of at least 5.6MPa and a seven-day unconfined compressive strength of at least 6.5 MPa.
7. A method for preparing the coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate as in any one of claims 1 to 6, characterized in that the following components are uniformly mixed by mass:
93% -97% of recycled concrete aggregate;
1.56% -3.12% of magnesium oxide;
0.57-1.90% of coal slag powder;
0.76% -1.80% of magnesium sulfate;
0.09% -0.18% of water-resistant additive.
8. The method of claim 7, further comprising adding water to the cinder powder magnesium oxysulfate cement stabilized recycled concrete aggregate for blending; wherein the mass of the water is 9.68-12.7% of the mass of the stable recycled concrete aggregate of the coal cinder powder magnesium oxysulfate cement.
CN201810595089.9A 2018-06-11 2018-06-11 Coal cinder powder magnesium oxysulfate cement stable recycled concrete aggregate and preparation method thereof Active CN108640635B (en)

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