CN111620584A - Method for modifying recycled aggregate - Google Patents
Method for modifying recycled aggregate Download PDFInfo
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- CN111620584A CN111620584A CN202010581682.5A CN202010581682A CN111620584A CN 111620584 A CN111620584 A CN 111620584A CN 202010581682 A CN202010581682 A CN 202010581682A CN 111620584 A CN111620584 A CN 111620584A
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- recycled aggregate
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/10—Coating or impregnating
- C04B20/12—Multiple coating or impregnating
Abstract
The invention discloses a method for modifying recycled aggregate, which comprises the steps of crushing the recycled aggregate, putting the crushed recycled aggregate into slurry prepared from redispersible latex powder, bentonite and magnesium aluminum silicate, soaking the crushed recycled aggregate into the slurry, fully and uniformly mixing the slurry, standing the slurry for initial setting, fishing out the slurry, washing the slurry with water and draining the slurry to obtain primary modified recycled aggregate; and (3) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate, soaking the primary modified recycled aggregate in the recycled aggregate, taking out the recycled aggregate, and airing to obtain the modified recycled aggregate. The method comprises the steps of firstly modifying the slurry prepared from the redispersible latex powder, the bentonite and the magnesium aluminum silicate, and then soaking the modified slurry by using the sodium carboxymethylcellulose, the tetramethylammonium cage polysilsesquioxane and the polymethyl methacrylate, so that the strength of the recycled aggregate can be obviously improved, the void ratio and the water absorption rate of the recycled aggregate are reduced, and the recycled concrete can be widely applied to concrete.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a method for modifying recycled aggregate.
Background
With the rapid development of economy, waste generated by the building industry has become a nuisance in many big cities in China. These wastes not only cause serious damage to the environment, but also compete with human beings for living space, and seriously affect the sustainable development of the country. Therefore, the development of new technologies for reducing, recycling and utilizing construction waste is urgent. Construction waste is mainly generated during the removal of old buildings and the construction of new buildings, and thus, the reduction of buildings necessitates the adoption of advanced management techniques and removal construction techniques in removal and construction works. It is well known that construction waste is generally composed of concrete fragments, clay bricks and tiles, sand and dust, wood chips, plastics and waste paper, waste metals, etc. Concrete fragments are usually the largest constituent of construction waste, and the crushed and screened concrete fragments can be used to replace natural aggregates in concrete or to serve as the foundation of roads, and this type of recycled material is called recycled aggregates.
Recycled aggregates have been successfully used in the building industry in some countries developed in europe and america, but are mainly used on the basis of non-structural concrete and roads, mainly due to the problems of rough surface, high porosity, high water absorption, high crushing rate and the like of the recycled aggregates. Therefore, when recycled aggregates are used to manufacture concrete, there are disadvantages in that slump of the concrete is difficult to control, strength is low, elastic modulus is lowered, dry shrinkage and creep are high, and durability is poor, resulting in very limited use of the recycled aggregates in structural concrete. In order to expand the wide application of the recycled aggregate in concrete, the recycled aggregate needs to be modified so as to improve the performance of the recycled aggregate.
The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.
Disclosure of Invention
The invention provides a method for modifying recycled aggregate and recycled concrete aiming at the problems of the recycled aggregate. The method comprises the steps of firstly modifying the slurry prepared from the redispersible latex powder, the bentonite and the magnesium aluminum silicate, and then soaking the modified slurry by using the sodium carboxymethylcellulose, the tetramethylammonium cage polysilsesquioxane and the polymethyl methacrylate, so that the strength of the recycled aggregate can be obviously improved, the void ratio and the water absorption rate of the recycled aggregate are reduced, and the recycled concrete can be widely applied to concrete.
A method for modifying recycled aggregate comprises the following steps:
(1) crushing the recycled aggregate, putting the crushed recycled aggregate into a slurry prepared from redispersible latex powder, bentonite and magnesium aluminum silicate, soaking the crushed recycled aggregate, fully and uniformly mixing the crushed recycled aggregate and the slurry, standing the mixture until the slurry is initially solidified, taking the slurry out, washing the slurry with water and draining the slurry to obtain primary modified recycled aggregate;
(2) and (3) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate, soaking the primary modified recycled aggregate in the recycled aggregate, taking out the recycled aggregate, and airing to obtain the modified recycled aggregate.
Furthermore, the addition amount of the redispersed latex powder, bentonite and magnesium aluminum silicate is 5-15% of the mass of the recycled aggregate.
Further, the mass ratio of the redispersed latex powder to the bentonite to the magnesium aluminum silicate is 1-3:10-20: 5-10.
Furthermore, the addition amount of the sodium carboxymethylcellulose, the tetramethylammonium cage polysilsesquioxane and the polymethyl methacrylate is 1-3% of the mass of the recycled aggregate.
Further, the mass ratio of the sodium carboxymethylcellulose to the tetramethylammonium cage polysilsesquioxane to the polymethyl methacrylate is 5-10:1-3: 3-5.
Further, the crushing is to a particle size of 5-40 mm.
Further, the soaking is carried out for 6-24 h.
Compared with the prior art, the invention has the advantages and beneficial effects that:
1. the method of the invention uses the slurry prepared by the re-dispersible latex powder, the bentonite and the magnesium aluminum silicate to carry out primary surface modification on the recycled concrete, thereby not only filling gaps and cracks, reducing the void ratio and the crushing index of the recycled aggregate, improving the mechanical property of the aggregate, but also improving the surface morphology of the recycled aggregate, enabling the surface to be smoother and increasing the compactness and the strength of the recycled aggregate.
2. The method also uses sodium carboxymethyl cellulose, tetramethyl ammonium cage polysilsesquioxane and polymethyl methacrylate to soak and modify the recycled aggregate again, and a layer of film is formed on the surface of the recycled aggregate, so that the water absorption rate of the recycled aggregate can be reduced, the cohesiveness of slurry in recycled concrete is improved, and the compressive strength of the recycled concrete is improved.
3. The recycled aggregate obtained by modification by the method has the advantages of low porosity, high strength, low water absorption, low crushing index and the like, overcomes the defects of the existing recycled aggregate, expands the application of the recycled aggregate in concrete, reduces the discharge of construction waste, and has good economic, social and ecological benefits.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.
Example 1
A method for modifying recycled aggregate is characterized by comprising the following steps: the method comprises the following steps:
(1) crushing the waste concrete to 5-20mm, putting the waste concrete into a slurry prepared from redispersible latex powder, bentonite and magnesium aluminum silicate in a mass ratio of 2:15:8, and soaking, wherein the addition amount of the redispersible latex powder, the bentonite and the magnesium aluminum silicate is 10% of the mass of the recycled aggregate, fully and uniformly mixing, standing for initial setting of the slurry, taking out, washing with water and draining to obtain a primary modified recycled aggregate;
(2) and (2) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate in a mass ratio of 5:2:3, wherein the addition amount of the sodium carboxymethylcellulose, the tetramethylammonium polyhedral oligomeric silsesquioxane and the polymethyl methacrylate is 2% of the mass of the recycled aggregate, soaking for 12h without the recycled aggregate, taking out, and airing to obtain the modified recycled aggregate.
Example 2
A method for modifying recycled aggregate is characterized by comprising the following steps: the method comprises the following steps:
(1) crushing the waste concrete to 5-20mm, putting a slurry prepared from 3:10:7 mass ratio of re-dispersible latex powder, bentonite and magnesium aluminum silicate into the waste concrete, soaking the waste concrete, wherein the addition amount of the re-dispersible latex powder, the bentonite and the magnesium aluminum silicate is 18% of the mass of the recycled aggregate, fully and uniformly mixing, standing, waiting for the slurry to be initially solidified, taking out, washing with water and draining to obtain a primary modified recycled aggregate;
(2) and (2) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate in a mass ratio of 8:2:2, wherein the addition amount of the sodium carboxymethylcellulose, the tetramethylammonium polyhedral oligomeric silsesquioxane and the polymethyl methacrylate is 2.4% of the mass of the recycled aggregate, soaking the recycled aggregate for 20 hours, taking out and airing to obtain the modified recycled aggregate.
Example 3
A method for modifying recycled aggregate is characterized by comprising the following steps: the method comprises the following steps:
(1) crushing the waste concrete to 5-20mm, putting the waste concrete into a slurry prepared from re-dispersible latex powder, bentonite and magnesium aluminum silicate in a mass ratio of 2:18:5, and soaking, wherein the addition amount of the re-dispersible latex powder, the bentonite and the magnesium aluminum silicate is 15% of the mass of the recycled aggregate, fully mixing uniformly, standing for initial setting of the slurry, taking out, washing with water and draining to obtain a primary modified recycled aggregate;
(2) and (2) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate in a mass ratio of 7:3:5, wherein the addition amount of the sodium carboxymethylcellulose, the tetramethylammonium polyhedral oligomeric silsesquioxane and the polymethyl methacrylate is 1.5% of the mass of the recycled aggregate, soaking for 24h without the recycled aggregate, taking out, and airing to obtain the modified recycled aggregate.
Example 4
A method for modifying recycled aggregate is characterized by comprising the following steps: the method comprises the following steps:
(1) crushing the waste concrete to 5-20mm, putting a slurry prepared from re-dispersible latex powder, bentonite and magnesium aluminum silicate in a mass ratio of 1:15:8 into the waste concrete, soaking the waste concrete, wherein the addition amount of the re-dispersible latex powder, the bentonite and the magnesium aluminum silicate is 9% of the mass of the recycled aggregate, fully and uniformly mixing, standing, taking out after the slurry is initially solidified, washing with water and draining to obtain a primary modified recycled aggregate;
(2) and (2) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate according to the mass ratio of 8:2:3, wherein the adding amount of the sodium carboxymethylcellulose, the tetramethylammonium polyhedral oligomeric silsesquioxane and the polymethyl methacrylate is 2.6% of the mass of the recycled aggregate, soaking for 12h without the recycled aggregate, taking out, and airing to obtain the modified recycled aggregate.
The modified recycled aggregates obtained in examples 1 to 4 were subjected to the test method defined in GB14684-2011 to measure the saturated surface dry water absorption and crush index of the recycled aggregates. The modified recycled aggregate obtained in the embodiments 1 to 4 is used for preparing concrete, and the formula of the concrete is as follows: 150 parts of modified recycled aggregate, 120 parts of cement, 250 parts of sand and water are stirred into concrete according to a conventional method, and the 28-day compressive strength of the concrete is measured according to a specified method of GB/T50081-2002 standard on mechanical property test method of common concrete. Wherein, the comparative example is waste concrete with unmodified grain diameter of 5-20mm, and the test result is shown in table 1.
Table 1: performance test results of the modified recycled aggregate of the invention
| Product(s) | Water absorption (%) | Crush index (%) | 28 days compressive strength (MPa) |
| Example 1 | 2.34 | 9.73 | 56.41 |
| Example 2 | 2.17 | 8.24 | 63.67 |
| Example 3 | 2.53 | 9.16 | 61.28 |
| Example 4 | 2.05 | 11.25 | 52.12 |
| Comparative example | 12.78 | 21.37 | 31.60 |
From the test results, the recycled aggregate obtained by modification by the method has the advantages of low porosity, high strength, low water absorption and the like, overcomes the defects of the existing recycled aggregate, expands the application of the recycled aggregate in concrete, reduces the discharge of construction waste, and has good economic, social and ecological benefits.
The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and such substitutions and modifications are to be considered as within the scope of the invention.
Claims (7)
1. A method for modifying recycled aggregate is characterized by comprising the following steps: the method comprises the following steps:
(1) crushing the recycled aggregate, putting the crushed recycled aggregate into a slurry prepared from redispersible latex powder, bentonite and magnesium aluminum silicate, soaking the crushed recycled aggregate, fully and uniformly mixing the crushed recycled aggregate and the slurry, standing the mixture until the slurry is initially solidified, taking the slurry out, washing the slurry with water and draining the slurry to obtain primary modified recycled aggregate;
(2) and (3) putting the primary modified recycled aggregate into a soaking solution consisting of sodium carboxymethylcellulose, tetramethylammonium polyhedral oligomeric silsesquioxane and polymethyl methacrylate, soaking the primary modified recycled aggregate in the recycled aggregate, taking out the recycled aggregate, and airing to obtain the modified recycled aggregate.
2. The method for modifying recycled aggregate according to claim 1, wherein: the addition amount of the redispersed latex powder, the bentonite and the magnesium aluminum silicate is 5-15% of the mass of the recycled aggregate.
3. The method for modifying recycled aggregate according to claim 2, wherein: the mass ratio of the re-dispersed latex powder to the bentonite to the magnesium aluminum silicate is 1-3:10-20: 5-10.
4. The method for modifying recycled aggregate according to claim 1, wherein: the addition amount of the sodium carboxymethylcellulose, the tetramethylammonium polyhedral oligomeric silsesquioxane and the polymethyl methacrylate is 1-3% of the mass of the recycled aggregate.
5. The method for modifying recycled aggregate according to claim 4, wherein: the mass ratio of the sodium carboxymethylcellulose to the tetramethylammonium cage polysilsesquioxane to the polymethyl methacrylate is 5-10:1-3: 3-5.
6. The method for modifying recycled aggregate according to claim 1, wherein: the crushing is to a particle size of 5-40 mm.
7. The method for modifying recycled aggregate according to claim 1, wherein: the soaking is carried out for 6-24 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010581682.5A CN111620584A (en) | 2020-06-23 | 2020-06-23 | Method for modifying recycled aggregate |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010581682.5A CN111620584A (en) | 2020-06-23 | 2020-06-23 | Method for modifying recycled aggregate |
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| CN202010581682.5A Withdrawn CN111620584A (en) | 2020-06-23 | 2020-06-23 | Method for modifying recycled aggregate |
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Cited By (5)
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| CN112194398A (en) * | 2020-10-12 | 2021-01-08 | 北京联绿技术集团有限公司 | Preparation method of waste brick aggregate |
| CN112374837A (en) * | 2020-12-01 | 2021-02-19 | 深圳市汇基砼混凝土有限公司 | Recycled concrete and preparation method thereof |
| CN112374827A (en) * | 2020-09-16 | 2021-02-19 | 湖州上建华煜混凝土有限公司 | Recycled aggregate concrete and preparation method thereof |
| CN113443879A (en) * | 2021-07-24 | 2021-09-28 | 陕西秦汉恒盛新型建材科技股份有限公司 | Lightweight aggregate concrete produced by utilizing recycled lightweight aggregate and production process thereof |
| CN115677251A (en) * | 2022-10-31 | 2023-02-03 | 浙江交工集团股份有限公司 | Preparation method of waste concrete recycled aggregate |
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Cited By (8)
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| CN112374827A (en) * | 2020-09-16 | 2021-02-19 | 湖州上建华煜混凝土有限公司 | Recycled aggregate concrete and preparation method thereof |
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| CN113443879A (en) * | 2021-07-24 | 2021-09-28 | 陕西秦汉恒盛新型建材科技股份有限公司 | Lightweight aggregate concrete produced by utilizing recycled lightweight aggregate and production process thereof |
| CN113443879B (en) * | 2021-07-24 | 2022-09-30 | 陕西秦汉恒盛新型建材科技股份有限公司 | Lightweight aggregate concrete produced by utilizing recycled lightweight aggregate and production process thereof |
| CN115677251A (en) * | 2022-10-31 | 2023-02-03 | 浙江交工集团股份有限公司 | Preparation method of waste concrete recycled aggregate |
| CN115677251B (en) * | 2022-10-31 | 2024-03-22 | 浙江交工集团股份有限公司 | Preparation method of recycled aggregate of waste concrete |
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