CN110395963B - Construction waste recycled concrete - Google Patents

Construction waste recycled concrete Download PDF

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Publication number
CN110395963B
CN110395963B CN201910760637.3A CN201910760637A CN110395963B CN 110395963 B CN110395963 B CN 110395963B CN 201910760637 A CN201910760637 A CN 201910760637A CN 110395963 B CN110395963 B CN 110395963B
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China
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recycled
concrete
parts
aggregate
waste
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CN110395963A (en
Inventor
文俊强
李彦昌
杨荣俊
庞永龙
张硕
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Beijing Gaoqiang Concrete Co ltd
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Beijing Gaoqiang Concrete Co ltd
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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
    • C04B28/18Compositions 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 mixtures of the silica-lime type

Abstract

The invention relates to construction waste recycled concrete, which belongs to the technical field of concrete, and the preparation raw materials comprise fly ash, stone powder, recycled coarse aggregate, recycled fine aggregate, an early strength agent, a water reducing agent, an air entraining agent and a reinforcing component; wherein, the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete; the reinforced components comprise basalt fibers, polypropylene reticular fibers, metakaolin and CABR-MS605 rust inhibitor. The invention can improve the impermeability of the recycled concrete.

Description

Construction waste recycled concrete
Technical Field
The invention relates to the technical field of concrete, in particular to construction waste recycled concrete.
Background
With the improvement of environmental awareness, more and more enterprises have recently started to prepare recycled concrete from construction waste.
A large amount of waste clay bricks and waste concrete exist in the construction waste generated by dismantling old buildings, so that the recycling of the waste clay bricks and the waste concrete is enhanced, the waste clay bricks and the waste concrete are used for preparing recycled concrete or producing concrete products, the method is one of effective ways for realizing the recycling of the construction waste, and has important practical significance. The recycled aggregate is obtained by mechanically crushing and grading and screening the waste bricks and the waste concrete to replace natural sandstone, so that the consumption of the natural sandstone is reduced, and the cost is saved.
The above prior art solutions have the following drawbacks: the recycled coarse aggregate obtained from the waste bricks has a rough surface, micro cracks, more pores and higher porosity; the recycled fine aggregate obtained from the concrete has small bulk density and large porosity, and influences the impermeability of the recycled concrete.
Disclosure of Invention
The invention aims to provide construction waste recycled concrete, and the impermeability of the recycled concrete is improved.
The above object of the present invention is achieved by the following technical solutions:
the construction waste recycled concrete is prepared from the following raw materials, by weight, 65-85 parts of fly ash, 25-34 parts of stone powder, 350-390 parts of recycled coarse aggregate, 320-370 parts of recycled fine aggregate, 28-40 parts of early strength agent, 0.5-1.3 parts of water reducing agent, 3-5 parts of air entraining agent and 2-7 parts of reinforcing component; wherein the content of the first and second substances,
the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete;
the reinforced components comprise basalt fibers, polypropylene reticular fibers, metakaolin and CABR-MS605 rust inhibitor, wherein the weight part ratio of the basalt fibers, the polypropylene reticular fibers, the metakaolin and the CABR-MS605 rust inhibitor is 1: 1.1-1.9: 1.2-1.7: 0.2-0.9.
By adopting the technical scheme, firstly, the main solid waste fly ash discharged by a coal power plant is selected as a cementing material to replace cement; the waste bricks and waste concrete are crushed and screened to be used as recycled coarse aggregate and recycled fine aggregate, so that natural sandstone is completely replaced, the production cost can be greatly reduced, and resources are saved.
However, the fly ash has a porous structure and large porosity, and meanwhile, the porosity of the recycled coarse aggregate and the recycled fine aggregate is also large, so that the impermeability, the chloride ion permeability resistance and the sulfate erosion resistance of the recycled concrete are all reduced compared with those of common concrete. Thus, stone powder, reinforcing components and various additives are added into the preparation raw materials.
The stone powder and the fly ash form good gradation, so that the concrete has good fluidity and cohesiveness, the gaps among the aggregates can be effectively filled, the aggregates are better adhered and wrapped, a dense concrete micro-pore structure is formed, and the impermeability of the concrete is improved.
The reinforced components comprise basalt fibers, polypropylene reticular fibers, metakaolin and CABR-MS605 rust inhibitor. After the concrete is hydrated, the hydrated calcium silicate and calcium hydroxide crystals are mutually filled to form a relatively dense structure, but some crystal combination defects and loose and broken structures such as lamellar Ca (OH)2The structure is easy to generate cracks and cause the expansion of the shrinkage crack, and meanwhile, the original pores are randomly distributed in the matrix, and the porosity is high.
The addition of basalt fiber and polypropylene reticular fiber makes the microstructure of concrete more compact, and the pores in a great amount of hydrate gel C-S-H are filled with Ca (OH)2Crystals, so that the original pores are greatly reduced and the porosity is reduced. The surface of the basalt fiber is provided with protrusions which can be tightly occluded with aggregate, so that the interface strength between the fiber and the mortar matrix is improved, and the protrusions are uniformly distributed randomly, so that the internal structure is more compact.
The polypropylene reticular fibers are a bundle of fibers interwoven into a reticular shape, have strong binding force with the fly ash and the aggregate, can automatically open under impact when being stirred with the fly ash and the aggregate to form a single monofilament or mutually dragging multidirectional distribution fibers, form a disorderly support system in the concrete, effectively improve the anti-permeability and impact resistance of the recycled concrete, and enhance the toughness and wear resistance of the concrete.
Metakaolin is a highly active artificial pozzolanic material, which can react with Ca (OH) generated during the hydration of fly ash2The metakaolin has good compatibility with the fly ash and the aggregate and is easy to disperse in the mixture, and the metakaolin is matched with a water reducing agent to further enhance the performance of the concrete.
The metakaolin and the basalt fiber are related to the hydration process of the fly ash, the rust inhibitor can promote the hydration reaction of the fly ash, assist the basalt fiber and the metakaolin to play a role, simultaneously improve the compactness of concrete, further improve the micro-pore structure of the concrete, reduce the porosity and improve the impermeability of the concrete.
In addition, the early strength agent can accelerate the hydration speed, promote the development of the early strength of the concrete and improve the strength of the recycled concrete so as to make up the influence of the recycled aggregate on the recycled concrete; the concrete has micro dispersed air cannons, and the addition of the air entraining agent can reduce the number of open capillaries in unit volume, thereby improving the porosity of the concrete.
The invention firstly selects the fly ash, the waste brick and the waste concrete as basic raw materials to achieve the effect of reducing the production cost, and also adds the stone powder to improve the compactness of the recycled concrete, and adds the reinforcing component and the additive to be matched for use to achieve the effects of reducing the porosity and improving the impermeability of the recycled concrete.
The invention is further configured to: the weight part ratio of the basalt fiber, the polypropylene reticular fiber, the metakaolin and the CABR-MS605 rust inhibitor is 1: 1.3-1.7: 1.4-1.6: 0.4-0.8.
The invention is further configured to: the method is characterized in that: the preparation raw material also comprises 0.2-0.8 part of sodium gluconate.
By adopting the technical scheme, the sodium gluconate can be used as a retarder, so that the hydration time of the fly ash is prolonged, and the basalt fibers and the metakaolin are further promoted to play a role.
The invention is further configured to: the preparation raw materials comprise 0.4-0.6 part of sodium gluconate, 0.7-1.1 part of water reducing agent and 3.2-5.8 parts of reinforcing component.
The invention is further configured to: the early strength agent is prepared from sodium sulfate and triethanolamine according to the weight part ratio of 1: 1.5-1.8.
The invention is further configured to: the water reducing agent is selected from a polycarboxylic acid water reducing agent.
The invention is further configured to: the air entraining agent is selected from fatty alcohol sulfonate.
The invention is further configured to: the particle size of the recycled coarse aggregate is 15-25 mm.
The invention is further configured to: the particle size of the recycled fine aggregate is 1.4-4.5 mm.
By adopting the technical scheme, the aggregate has smaller particle size, and the damage is easy to form through cracks when the recycled aggregate is prepared by crushing, so that the strength of the aggregate is influenced; if the particle size of the aggregate is too large, the total area of the aggregate becomes small, the number of contact points among the particle sizes is reduced, the workability of the slurry becomes poor, and the segregation is severe, so that the particle sizes of the recycled coarse aggregate and the recycled fine aggregate need to be strictly controlled.
In conclusion, the beneficial technical effects of the invention are as follows:
1. the addition of the basalt fibers, the polypropylene reticular fibers and the metakaolin enables the microstructure of the concrete to be more compact, and effectively improves the anti-permeability and impact resistance of the recycled concrete; the corrosion inhibitor can promote the hydration reaction of the fly ash, assist the basalt fiber and the metakaolin to play a role, and can further improve the compactness of concrete;
2. the early strength agent can accelerate the hydration speed, promote the development of the early strength of the concrete and improve the strength of the recycled concrete so as to make up the influence of the recycled aggregate on the recycled concrete;
3. the sodium gluconate can be used as a retarder, prolongs the hydration time of the fly ash and further promotes the basalt fibers and the metakaolin to play a role.
Detailed Description
The present invention will be described in further detail below.
The basalt fiber with the length of 3-6mm and the diameter of 9-12 μm and the polypropylene reticular fiber with the length of 10-15mm and the diameter of 13-20 μm are selected in the following examples, and the physical parameters of the cement selected from ordinary portland cement, recycled coarse aggregate and recycled fine aggregate are shown in table a.
Table a physical parameters of recycled aggregate
Water absorption (%) Apparent density (kg/m)3) Crush number
Recycled fine aggregate 2.7 2365 10
Recycled coarse aggregate 3.1 2378 11
Example 1
The construction waste recycled concrete is prepared from the following raw materials, by weight, 65 parts of fly ash, 25 parts of stone powder, 350 parts of recycled coarse aggregate, 320 parts of recycled fine aggregate, 28 parts of early strength agent, 0.5 part of polycarboxylate superplasticizer, 3 parts of fatty alcohol sulfonate, 2 parts of reinforcing component and 0.2 part of sodium gluconate; wherein, the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete; the early strength agent is a mixture of sodium sulfate and triethanolamine in a ratio of 1: 1.5; the reinforcing components are basalt fiber, polypropylene reticular fiber, metakaolin, CABR-MS605 rust inhibitor 1: 1.1: 1.2: 0.2 of the mixture.
Example 2
The construction waste recycled concrete is prepared from the following raw materials, by weight, 74 parts of fly ash, 28 parts of stone powder, 375 parts of recycled coarse aggregate, 345 parts of recycled fine aggregate, 32 parts of early strength agent, 0.9 part of polycarboxylic acid water reducing agent, 4 parts of fatty alcohol sulfonate, 5 parts of reinforcing component and 0.5 part of sodium gluconate; wherein, the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete; the early strength agent is a mixture of sodium sulfate and triethanolamine in a ratio of 1: 1.6; the reinforcing components are basalt fiber, polypropylene reticular fiber, metakaolin, CABR-MS605 rust inhibitor 1: 1.5: 1.5: 0.6 of the mixture.
Example 3
The construction waste recycled concrete is prepared from the following raw materials, by weight, 85 parts of fly ash, 34 parts of stone powder, 390 parts of recycled coarse aggregate, 370 parts of recycled fine aggregate, 40 parts of early strength agent, 1.3 parts of polycarboxylate superplasticizer, 5 parts of fatty alcohol sulfonate, 7 parts of reinforcing component and 0.8 part of sodium gluconate; wherein, the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete; the early strength agent is a mixture of sodium sulfate and triethanolamine with a ratio of 1: 1.8; the reinforcing components are basalt fiber, polypropylene reticular fiber, metakaolin, CABR-MS605 rust inhibitor 1: 1.9: 1.7: 0.9 of a mixture.
Example 4
The construction waste recycled concrete is different from the concrete in embodiment 2 in that 0.4 part of sodium gluconate, 0.7 part of polycarboxylate superplasticizer and 3.2 parts of reinforcing component are calculated according to parts by weight.
Example 5
The construction waste recycled concrete is different from the concrete in example 2 in that 0.6 part of sodium gluconate, 1.1 part of polycarboxylate superplasticizer and 5.8 parts of reinforcing component are calculated according to parts by weight.
Example 6
The construction waste recycled concrete is different from the concrete in example 2 in that the weight part ratio of basalt fibers, polypropylene reticular fibers, metakaolin and CABR-MS605 rust inhibitor in the reinforcing component is 1: 1.3: 1.4: 0.4.
example 7
The construction waste recycled concrete is different from the concrete in example 2 in that the weight part ratio of basalt fibers, polypropylene reticular fibers, metakaolin and CABR-MS605 rust inhibitor in the reinforcing component is 1: 1.7: 1.6: 0.8.
example 8
A construction waste recycled concrete is different from example 2 in that the recycled coarse aggregate has a particle size of 15 mm.
Example 9
A construction waste recycled concrete is different from example 2 in that the recycled coarse aggregate has a particle size of 25 mm.
Example 10
A construction waste recycled concrete is different from example 2 in that the recycled coarse aggregate has a particle size of 20 mm.
Example 11
A construction waste recycled concrete is different from example 2 in that the recycled fine aggregate has a particle size of 1.4 mm.
Example 12
A construction waste recycled concrete is different from example 2 in that the recycled fine aggregate has a particle size of 2.8 mm.
Example 13
A construction waste recycled concrete is different from example 2 in that the recycled fine aggregate has a particle size of 4.5 mm.
Comparative example 1
Commercially available concrete.
Performance detection
The impermeability of the concrete is detected by referring to national standard GB/T50082-2009 test method standards for long-term performance and durability of common concrete, and the detection result is shown in Table 1; the porosity was calculated according to the test method of "test procedure for hydraulic concrete", and the results are shown in Table 1.
Table 1 results of impermeability tests of examples 1 to 13 and comparative example 1
As can be seen from table 1, the porosity was lower as compared to examples 1 to 13, and the chloride ion permeability and the water pressure resistance permeability were excellent, and the recycled concrete obtained by the preparation method of the present invention had better anti-permeability performance as compared to comparative example 1.
In examples 4-5, the addition amounts of sodium gluconate, a polycarboxylic acid water reducing agent and a reinforcing component are changed, and the sodium gluconate can be used as a retarder to prolong the hydration time of the fly ash and further promote the basalt fibers and metakaolin to play roles; the metakaolin is matched with a polycarboxylic acid water reducing agent to further enhance the performance of concrete; therefore, the proportion of the sodium gluconate, the polycarboxylate superplasticizer and the reinforcing component is very important.
In examples 6 to 7, the proportions of the respective components in the reinforcing component were changed, metakaolin and basalt fiber were both related to the hydration process of fly ash, and the rust inhibitor promoted the hydration reaction of fly ash, thereby assisting the basalt fiber and metakaolin in functioning and further improving the impermeability of the recycled concrete.
In examples 8 to 13, the particle sizes of the recycled fine aggregate and the recycled coarse aggregate were changed, and it is apparent from the examination data that when the particle size of the recycled fine aggregate was 1.4 to 4.5mm and the particle size of the recycled coarse aggregate was 15 to 25mm, the anti-permeability performance of the recycled concrete was more excellent than that of comparative example 1, and the particle size of the recycled aggregate was one of the factors affecting the anti-permeability performance of the recycled concrete.
The invention firstly selects the fly ash, the waste brick and the waste concrete as basic raw materials to achieve the effect of reducing the production cost, and the stone powder is added to improve the compactness of the recycled concrete, and the reinforcing component and the additive are added for matching use to achieve the effect of reducing the porosity and improving the impermeability of the recycled concrete.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims (1)

1. The construction waste recycled concrete is characterized in that the preparation raw materials comprise 74 parts of fly ash, 28 parts of stone powder, 375 parts of recycled coarse aggregate, 345 parts of recycled fine aggregate, 32 parts of early strength agent, 0.9 part of polycarboxylic acid water reducing agent, 4 parts of fatty alcohol sulfonate, 5 parts of reinforcing component and 0.5 part of sodium gluconate; wherein, the recycled coarse aggregate is formed by crushing and screening waste bricks, and the recycled fine aggregate is formed by crushing and screening waste concrete; the early strength agent is a mixture of sodium sulfate and triethanolamine in a ratio of 1: 1.6; the reinforcing components are basalt fiber, polypropylene reticular fiber, metakaolin, CABR-MS605 rust inhibitor 1: 1.5: 1.5: 0.6 of the mixture.
CN201910760637.3A 2019-08-16 2019-08-16 Construction waste recycled concrete Active CN110395963B (en)

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CN110922124A (en) * 2019-11-18 2020-03-27 北京太平洋水泥制品有限公司 Concrete produced by using waste muddy water
CN110937859A (en) * 2019-12-13 2020-03-31 湖北环沙再生资源有限公司 Recycled concrete and preparation method thereof
CN111892349A (en) * 2020-08-23 2020-11-06 蔡念明 High-strength recycled concrete and preparation method thereof
CN112390589A (en) * 2020-11-16 2021-02-23 北京建工资源循环利用投资有限公司 Building garbage regeneration interlocking building block and preparation method thereof
CN112700824B (en) * 2021-01-13 2022-06-14 湖北工业大学 Method for establishing fiber concrete mesoscopic model
CN112960953A (en) * 2021-03-04 2021-06-15 河北建筑工程学院 Nano metakaolin recycled concrete and preparation method thereof
CN113480217A (en) * 2021-08-20 2021-10-08 武汉兴诚海水泥制品有限公司 Concrete production process for preparing concrete by using construction waste
CN113735488A (en) * 2021-09-13 2021-12-03 吴江永盛混凝土有限公司 Additive special for recycled concrete

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CN106517942A (en) * 2016-11-07 2017-03-22 哈尔滨工程大学 Basalt and polypropylene hybrid fiber reinforced concrete and preparing method
CN106777535B (en) * 2016-11-25 2020-07-28 深圳大学 Alkali-activated recycled concrete mix proportion design method and system
CN107010896A (en) * 2017-04-20 2017-08-04 福州大学 A kind of regeneration concrete for filling be chopped basalt fibre and regenerated coarse aggregate
CN107777981A (en) * 2017-11-02 2018-03-09 广东工业大学 A kind of regeneration concrete and preparation method thereof
CN107879681B (en) * 2017-11-27 2020-05-08 广东工业大学 Concrete slurry, alkali-activated light rubber recycled concrete and preparation method thereof

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