阅读说明：本技术 一种再生混凝土骨料的制备工艺及其应用 (Preparation process and application of recycled concrete aggregate ) 是由 吴晓琴 于 2020-07-10 设计创作，主要内容包括：本申请公开了一种再生混凝土骨料的制备工艺及其应用,涉及混凝土技术领域。该再生混凝土骨料的制备工艺包括以下步骤：S1,预处理,对收集回来的混凝土块进行锤击,并除去其中的钢筋和各种杂质；S2,破碎处理,对预处理后的混凝土块分别进行初步破碎处理和再次破碎处理；S3,强化处理,对破碎处理后的混凝土块进行强化处理,以增强再生混凝土骨料的性能；S4,筛分处理,对破碎处理后的混凝土块进行筛分,得到复合粒径要求的再生混凝土骨料颗粒；S5,分级处理,对筛分处理后得到的再生混凝土骨料颗粒进行风力分级处理,以除去粒径较小的微粉。本申请的制备工艺,能够提高再生混凝土骨料的品质,大幅度提高废弃混凝土的回收率,经济性高,操作方便。(The application discloses a preparation process and application of recycled concrete aggregate, and relates to the technical field of concrete. The preparation process of the recycled concrete aggregate comprises the following steps: s1, preprocessing, hammering the collected concrete blocks, and removing steel bars and various impurities in the concrete blocks; s2, crushing, namely, performing primary crushing treatment and secondary crushing treatment on the pretreated concrete block respectively; s3, performing strengthening treatment, namely, strengthening the concrete blocks after the crushing treatment to enhance the performance of the recycled concrete aggregate; s4, screening, namely screening the crushed concrete blocks to obtain recycled concrete aggregate particles with composite particle size requirements; and S5, grading, namely, carrying out air classification on the recycled concrete aggregate particles obtained after screening treatment to remove micro powder with small particle size. The preparation process can improve the quality of recycled concrete aggregate, greatly improve the recovery rate of waste concrete, and is high in economical efficiency and convenient to operate.)

1. The preparation process of the recycled concrete aggregate is characterized by comprising the following steps of:

s1, preprocessing, hammering the collected concrete blocks, and removing steel bars and various impurities in the concrete blocks;

s2, crushing, namely, performing primary crushing treatment and secondary crushing treatment on the pretreated concrete block respectively;

s3, performing strengthening treatment, namely, strengthening the concrete blocks after the crushing treatment to enhance the performance of the recycled concrete aggregate;

s4, screening, namely screening the crushed concrete blocks to obtain recycled concrete aggregate particles with composite particle size requirements;

and S5, grading, namely, carrying out air classification on the recycled concrete aggregate particles obtained after screening treatment to remove micro powder with small particle size.

2. The preparation process of recycled concrete aggregate according to claim 1, characterized in that the specific steps of the reinforcement treatment are:

pouring the recycled concrete aggregate particles into a pickling tank, soaking for 15-20min, taking out, cleaning with industrial water, washing off acid liquor on the surface of the aggregate, and then draining for 4-8 h;

and b, diluting the 1% PVA solution by 2-3 times with industrial water, pouring the drained recycled concrete aggregate particles into the diluted PVA solution, soaking for 45-50h, taking out, and drying at 50-60 ℃ to obtain the concrete aggregate.

3. The process for preparing recycled concrete aggregate according to claim 1, wherein in step S3, the particle diameters of the recycled concrete aggregate particles are < 5mm, 5-25mm, and 25-40mm, respectively.

4. The process for preparing recycled concrete aggregate according to claim 1, wherein in step S5, the particle size of the micropowder is less than 0.16 mm.

5. The process for preparing recycled concrete aggregate according to claim 1, wherein in step S1, the reinforcing bars are removed by a magnetic device and non-ferrous impurities are removed by a separation stage.

6. The process for preparing recycled concrete aggregate according to claim 1, wherein the primary crushing treatment is performed by a jaw crusher, and the secondary crushing treatment is performed by a cone crusher.

7. The recycled concrete aggregate manufacturing process of claim 1, wherein the screening process employs a double screen vibratory screen for screening, the double screen vibratory screen having an amplitude of 5-10mm and a frequency of 400-500 times/min.

8. The recycled concrete is characterized by comprising the following components in parts by weight:

portland cement: 330-350 parts;

mineral powder: 60-80 parts;

fly ash: 150-180 parts;

crushing stone: 400-450 parts;

recycled concrete aggregate: 800-1000 parts;

water reducing agent: 2.5-3.5 parts;

water: 190-210 parts;

the recycled concrete aggregate is prepared by the preparation process of the recycled concrete aggregate according to any one of claims 1 to 7.

9. The recycled concrete of claim 8, wherein the recycled concrete aggregate is composed of fine aggregate having a particle size of 0.5 to 1mm and coarse aggregate having a particle size of 4 to 8mm in a weight ratio of 2: 3.

Technical Field

The invention relates to the technical field of concrete, in particular to a preparation process of recycled concrete aggregate and recycled concrete using the recycled concrete aggregate.

Background

With the development of society, various buildings and construction projects are increasing, and concrete members are widely applied to pole tower structures, industrial plants and columns and foundation piles of civil buildings. Along with the transformation of cities, a large amount of waste buildings in the cities form construction wastes, and the treatment of the construction wastes not only needs a large-area storage yard, but also costs a large amount of manpower and material resources. With the development of construction science, effective utilization of construction waste becomes a new topic.

At present, the process of recycling waste concrete aggregate at home and abroad is similar to the process of manufacturing natural crushed stone aggregate, only equipment for crushing, screening, conveying and the like of different crushed natural stones are reasonably combined together as much as possible, and manual or mechanical equipment is arranged on a proper link to remove impurities. However, the waste concrete and the natural crushed stone aggregate have various differences, the waste concrete contains more impurities including reinforcing steel bars, solidified cement blocks and the like, the production of the waste concrete recycled aggregate by adopting the production mode of the natural crushed stone aggregate obviously has various defects, and the quality of the recycled concrete aggregate is greatly different from that of the natural aggregate.

Therefore, a new solution is needed to solve the above problems.

Disclosure of Invention

Aiming at the problem of low quality of recycled concrete aggregate produced in the prior art, the first purpose of the application is to provide a preparation process of the recycled concrete aggregate, which can improve the quality of the recycled concrete aggregate, greatly improve the recovery rate of waste concrete, and has high economy and convenient operation.

The invention also aims to provide recycled concrete which has the advantages of good workability and high strength.

In order to achieve the first purpose, the invention provides the following technical scheme:

a preparation process of recycled concrete aggregate comprises the following steps:

s1, preprocessing, hammering the collected concrete blocks, and removing steel bars and various impurities in the concrete blocks;

s2, crushing, namely, performing primary crushing treatment and secondary crushing treatment on the pretreated concrete block respectively;

s3, performing strengthening treatment, namely, strengthening the concrete blocks after the crushing treatment to enhance the performance of the recycled concrete aggregate;

s4, screening, namely screening the crushed concrete blocks to obtain recycled concrete aggregate particles with composite particle size requirements;

and S5, grading, namely, carrying out air classification on the recycled concrete aggregate particles obtained after screening treatment to remove micro powder with small particle size.

By adopting the technical scheme and the preparation process, firstly, the recycled waste concrete blocks are hammered, so that the concrete blocks are obtained, and reinforcing steel bars and impurities in the concrete blocks are removed; then directly crushing the concrete fragments, and quickly crushing the concrete fragments to meet the requirements by using a combined crushing mode; then screening the crushed aggregate particles to obtain particles with different particle sizes meeting the requirements; and finally, carrying out wind power classification treatment on the screened recycled concrete aggregate particles to separate micro powder with smaller particle size. By adopting the preparation process of the recycled concrete aggregate, the quality of the recycled concrete aggregate can be improved, the recovery rate of the waste concrete is greatly improved, the economy is high, and the operation is convenient. Compared with the strengthening of the aggregate before crushing, the method has the advantages that the concrete blocks are firstly crushed, and then the crushed aggregate particles are subjected to strengthening treatment, so that the surface strengthening degree of the aggregate particles is high, the mechanical property is better, and the water absorption rate is lower.

More preferably, the strengthening treatment comprises the following specific steps:

pouring the recycled concrete aggregate particles into a pickling tank, soaking for 15-20min, taking out, cleaning with industrial water, washing off acid liquor on the surface of the aggregate, and then draining for 4-8 h;

and b, diluting the 1% PVA solution by 2-3 times with industrial water, pouring the drained recycled concrete aggregate particles into the diluted PVA solution, soaking for 45-50h, taking out, and drying at 50-60 ℃ to obtain the concrete aggregate.

By adopting the technical scheme, the surface of the recycled aggregate obtained by mechanical crushing is coated with partial waste mortar: the adhered cement slurry can directly affect the physical and mechanical properties of the recycled aggregate, such as low strength, high water absorption, low density, rough surface and the like of the recycled aggregate. By soaking in acid liquor, the components such as calcium oxide, aluminum oxide and ferric oxide in the cement paste can be subjected to neutralization reaction with acid, so that the cement paste on the surface of the aggregate is effectively removed, and the quality of the aggregate is improved.

As the recycled aggregate is continuously collided, extruded, ground and the like in the crushing process, a large number of microcracks are generated inside the aggregate, the porosity of the aggregate is high, the water absorption rate is high, the bulk density is low, the bulk porosity is high, and the performance of the recycled aggregate is obviously inferior to that of the natural aggregate. The PVA polymer solution is soaked, so that the adhesive has good adhesiveness and can be cured and molded in a relatively short time, and the aggregate is soaked in the PVA polymer solution, so that a layer of compact film can be formed on the surface of the aggregate while the cracks and micropores of the aggregate are filled, the porosity of the aggregate can be reduced, the water absorption is reduced, and the physical and mechanical properties of the aggregate are improved.

More preferably, in step S3, the recycled concrete aggregate particles have particle diameters of < 5mm, 5 to 25mm, and 25 to 40mm, respectively.

More preferably, in step S5, the fine powder has a particle size of less than 0.16 mm.

By adopting the technical scheme, the particle size of the recycled concrete aggregate particles obtained by the method is three types of particles of 0.16-5mm, 5-20mm and 20-50mm, according to the standard and test method for the sand quality for common concrete (JGJ 52-92) and the standard and test method for the pebble quality after the crushed stones for common concrete (JGJ53-92), the recycled concrete aggregate particles with the particle size of 0.16-5mm are used as recycled fine aggregates, and the particles with the particle size of more than 5mm are used as recycled coarse aggregates.

It is further preferable that the reinforcing bars are removed by a magnetic device and non-ferrous impurities are removed by a separation stage in step S1.

Through adopting above-mentioned technical scheme, adopt magnetic equipment and separation platform to detach reinforcing bar and other impurity to replace manual operation, not only safer and more high-efficient.

Preferably, the preliminary crushing treatment is performed by using a jaw crusher, and the secondary crushing treatment is performed by using a cone crusher.

Through adopting above-mentioned technical scheme, jaw breaker can carry out preliminary breakage to the concrete piece of big particle diameter, makes it break into the relatively less concrete piece of particle diameter, and the cone crusher further breaks the concrete piece after the breakage, makes it further break into less granule, adopts this kind of modular crushing mode, and work efficiency is high, and broken product high quality meets the requirements.

Further preferably, the screening treatment is carried out by adopting a double-screen vibrating screen, the amplitude of the double-screen vibrating screen is 5-10mm, and the frequency is 400-500 times/min.

By adopting the technical scheme, the crushed recycled concrete aggregate particles are screened into three aggregates with different particle sizes by adopting the double-screen vibrating screen, so that the working efficiency is high.

In order to achieve the second purpose, the invention provides the following technical scheme:

the recycled concrete is characterized by comprising the following components in parts by weight:

portland cement: 330-350 parts;

mineral powder: 60-80 parts;

fly ash: 150-180 parts;

crushing stone: 400-450 parts;

recycled concrete aggregate: 800-1000 parts;

water reducing agent: 2.5-3.5 parts;

water: 190-210 parts;

the recycled concrete aggregate is prepared by the preparation process of the recycled concrete aggregate.

By adopting the technical scheme, the concrete prepared by adopting the raw material proportion has the advantages of good working performance and high mechanical strength.

More preferably, the recycled concrete aggregate is composed of fine aggregate with the grain diameter of 0.5-1mm and coarse aggregate with the grain diameter of 4-8mm according to the weight ratio of 2: 3.

In summary, compared with the prior art, the invention has the following beneficial effects:

(1) by adopting the preparation process of the recycled concrete aggregate, the quality of the recycled concrete aggregate can be improved, the recovery rate of the waste concrete is greatly improved, the economy is high, and the operation is convenient;

(2) the method has the advantages that the recycled concrete aggregate is subjected to strengthening treatment, so that cement paste on the surface of the aggregate is effectively removed, the porosity of the aggregate is reduced, the water absorption is reduced, and the physical and mechanical properties of the aggregate are improved;

(3) according to the method, after the concrete blocks are crushed, the problem that reinforcing performance is reduced due to the fact that reinforcing is performed first and then crushing can be solved, so that the surface reinforcing degree of the aggregate particles is high, the mechanical property is better, and the water absorption rate is lower.

(4) According to the application, the self-made reinforced concrete aggregate is adopted, and other components are reasonably matched, so that the prepared recycled concrete has the advantages of good working performance and high mechanical strength.

Drawings

FIG. 1 is a flow chart of the process for preparing recycled concrete aggregate in example 1.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

The jaw crusher used in this application is of the type PE400 x 500, the minimum feed particle size is 350mm, the discharge particle size is set to 50mm, the throughput is 50t/h, and the power is 30 kw.

The model of the cone crusher used in the application is PYS36D, the feeding particle size is 50mm, the discharging particle size is 40mm, the processing capacity is 60t/h, and the power is 75 kw.

The amplitude of the double-screen vibrating screen used in the application is 5-10mm, and the frequency is 400-500 times/min.

The crushed stones in the application are continuously graded with the grain size of 5-20 mm; the Portland cement is 42.5-grade Portland cement; the mineral powder is S95 level granulated blast furnace slag powder; the water reducing agent adopts maleic anhydride and maleic anhydride type carboxylic acid water reducing agent with the weight ratio of 1: 1; and all the raw materials are commonly purchased in the market.