Zero-magnetism concrete with modified plastic replacing aggregate and preparation method of zero-magnetism concrete

Abstract

The invention discloses zero-magnetism concrete with aggregate replaced by modified plastics, which comprises non-magnetic cement, carbon nanotubes, cross-linked modified plastics, a silane coupling agent, deionized water and a water reducing agent, the zero-magnetism concrete is prepared from the following components in percentage by weight: 15.2 to 36.6 percent of non-magnetism cement, 0.5 to 2.0 percent of carbon nano tube, 40.2 to 62.0 percent of cross-linked modified plastic, 0.05 to 0.1 percent of silane coupling agent, 8 to 20 percent of deionized water and 0.2 to 1.3 percent of water reducing agent. The aggregate is replaced by the modified plastic, the plastic is free of iron element and extremely low in residual magnetism intensity, magnetic separation is not needed, the magnetic separation process of the traditional aggregate in the zero-magnetism concrete is reduced, and the cost is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and particularly relates to a zero-magnetic concrete using modified plastics instead of aggregates and a preparation method thereof. Background Art

[0002] With the rapid development of modern technology in the fields of precision instruments, quantum computing, biomedicine, etc., the weak magnetic field interference caused by residual magnetic substances in traditional building materials has become a key bottleneck restricting technological breakthroughs. Zero-magnetic concrete can create a highly sensitive space environment to magnetic field interference.

[0003] The aggregates in zero-magnetic concrete basically contain iron elements and require complex magnetic separation processes; plastics themselves do not contain iron elements and can meet the requirements of the aggregates in zero-magnetic concrete after modification treatment and surface treatment. By adding coupling agents and water reducers, zero-magnetic concrete meeting the requirements can be prepared. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies existing in the above-mentioned prior art. The present invention provides a zero-magnetic concrete using modified plastics instead of aggregates and a preparation method thereof. By using modified plastics instead of aggregates, the plastics themselves have no iron elements and the remanent magnetic intensity is extremely low, eliminating the need for magnetic separation, reducing the magnetic separation process of traditional aggregates in zero-magnetic concrete, and significantly reducing costs.

[0005] In order to achieve the above-mentioned invention purpose, the technical solutions provided by the present invention are as follows:

[0006] A zero-magnetic concrete using modified plastics instead of aggregates, which includes non-magnetic cement, carbon nanotubes, crosslinked modified plastics, silane coupling agent, deionized water and water reducer. The zero-magnetic concrete includes the following components by weight percentage: non-magnetic cement 15.2 - 36.6%, carbon nanotubes 0.5 - 2.0%, crosslinked modified plastics 40.2 - 62.0%, silane coupling agent 0.05 - 0.1%, deionized water 8 - 20% and water reducer 0.2 - 1.3%.

[0007] Further, the Fe content in the non-magnetic cement < 0.01%.

[0008] Further, the crosslinked modified plastics are obtained by modifying ordinary polyethylene plastics. Specifically, silane and ordinary polyethylene plastics react under the action of peroxide to form silane-grafted polyethylene, and then under the action of organotin compounds and water, the silane groups hydrolyze to form silanols, and further condense crosslinking bonds to obtain crosslinked modified plastics.

[0009] Further, the carbon nanotubes are multi-walled carbon nanotubes with a carbon nanotube purity > 98%.

[0010] Further, the silane coupling agent is a derivative of γ-aminopropyltriethoxysilane or methacryloxypropyltrimethoxysilane.

[0011] Further, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate of the water reducing agent is ≥ 30%.

[0012] A preparation method of zero-magnetic concrete using a modified plastic to replace aggregate, the method specifically includes the following steps:

[0013] S1, Mix non-magnetic cement and carbon nanotubes and stir evenly to obtain gel material A, and the stirring time is not less than 2 min;

[0014] S2, Mix deionized water, silane coupling agent and water reducing agent and stir evenly to obtain admixture B, pour admixture B into gel material A and mix and stir evenly to obtain mixture C, and the stirring time is not less than 1 min;

[0015] S3, Pour the pretreated cross-linked modified plastic into mixture C and mix and stir evenly to obtain zero-magnetic concrete, and the stirring time is not less than 2 min.

[0016] Further, the pretreatment of the cross-linked modified plastic is: the cross-linked modified plastic is subjected to sandblasting treatment, and the surface of the plastic is impacted by the abrasives sprayed at high speed to form pits, so that the gel material fits more closely with the cross-linked modified plastic.

[0017] Further, the fluidity of the zero-magnetic concrete is greater than 160 mm, the 28-day compressive strength of the zero-magnetic concrete is greater than 50 Mpa, and the remanent magnetic strength of the zero-magnetic concrete is less than 5 nT.

[0018] Based on the above technical solutions, the following technical effects have been achieved through practical application of the zero-magnetic concrete and its preparation method using a modified plastic to replace aggregate in the present invention:

[0019] 1. The zero-magnetic concrete using a modified plastic to replace aggregate in the present invention replaces the aggregate with a modified plastic. The plastic itself has no iron element and has an extremely low remanent magnetic strength. There is no need for magnetic separation, reducing the magnetic separation process of traditional aggregates in zero-magnetic concrete, and greatly reducing the cost.

[0020] 2. The zero-magnetic concrete using a modified plastic to replace aggregate in the present invention improves the compressive strength of the zero-magnetic concrete by modifying the plastic and adding carbon nanotubes.

[0021] 3. The preparation method of the zero-magnetic concrete using a modified plastic to replace aggregate in the present invention improves the problem of poor interfacial bonding between the plastic and the cement by treating the plastic surface and adding silane coupling agent and other technical means. Specific embodiments

[0022] To make the objectives, technical solutions, and effects of the present invention clearer and more understandable, the present invention will be described below through specific examples. However, it should be understood that these descriptions are only exemplary and do not intend to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0023] A zero-magnetic concrete using a modified plastic to replace aggregate, the zero-magnetic concrete comprising non-magnetic cement, carbon nanotubes, crosslinked modified plastic, silane coupling agent, deionized water, and water reducer. The zero-magnetic concrete comprises the following components by weight percentage: non-magnetic cement 15.2 - 36.6%, carbon nanotubes 0.5 - 2.0%, crosslinked modified plastic 40.2 - 62.0%, silane coupling agent 0.05 - 0.1%, deionized water 8 - 20%, and water reducer 0.2 - 1.3%.

[0024] The Fe content in the non-magnetic cement < 0.01%.

[0025] The crosslinked modified plastic is obtained by modifying ordinary polyethylene plastic. Specifically, silane and ordinary polyethylene plastic react under the action of peroxide to generate silane-grafted polyethylene. Then, under the action of organotin compounds and water, the silane groups hydrolyze to form silanols, and further condense crosslinking bonds to obtain the crosslinked modified plastic.

[0026] By using a modified plastic to replace the aggregate, the plastic itself has no iron element and the residual magnetic strength is extremely low, eliminating the need for magnetic separation, reducing the magnetic separation process of traditional aggregates in zero-magnetic concrete, and significantly reducing costs.

[0027] The carbon nanotubes are multi-walled carbon nanotubes with a carbon nanotube purity > 98%.

[0028] The silane coupling agent is a derivative of γ-aminopropyltriethoxysilane or methacryloxypropyltrimethoxysilane.

[0029] Further, the water reducer is a polycarboxylate water reducer with a water reduction rate of the water reducer ≥ 30%.

[0030] A method for preparing a zero-magnetic concrete using a modified plastic to replace aggregate, the method specifically comprising the following steps:

[0031] S1, mixing the non-magnetic cement and carbon nanotubes and stirring evenly to obtain a gel material A, with the stirring time not less than 2 min;

[0032] S2, mixing deionized water, silane coupling agent, and water reducer and stirring evenly to obtain an admixture B, pouring the admixture B into the gel material A and mixing and stirring evenly to obtain a mixture C, with the stirring time not less than 1 min;

[0033] S3. Pour the pretreated cross-linked modified plastic into the mixing material C, mix and stir evenly to obtain non-magnetic concrete, and the stirring time is not less than 2 minutes.

[0034] The pretreatment of the cross-linked modified plastic is as follows: the cross-linked modified plastic is subjected to sandblasting treatment, and the surface of the plastic is impacted by the abrasives ejected at high speed to form pits, so that the cementitious material fits more closely with the cross-linked modified plastic.

[0035] By means of technical means such as treating the plastic surface and adding silane coupling agent, the problem of poor interfacial bonding between the plastic and the cement is improved.

[0036] The fluidity of the non-magnetic concrete is greater than 160 mm, the 28-day compressive strength of the non-magnetic concrete is greater than 50 Mpa, and the remanent magnetic strength of the non-magnetic concrete is less than 5 nT.

[0037] In the embodiment of the present invention

[0038] The test method for the fluidity of the zero-magnetic concrete is carried out in accordance with JGJ / T70-2009, the test method for the compressive strength is carried out in accordance with GB / T50081-2019, and the test method for the remanent magnetic strength is carried out in accordance with EN50147-3.

[0039] The cement is non-magnetic cement with a strength grade of 52.5;

[0040] The water reducing agent is a polycarboxylic acid liquid water reducing agent;

[0041] The modification of the cross-linked modified plastic is to generate silane-grafted polyethylene by reacting silane with ordinary polyethylene plastic under the action of peroxide, and then under the action of organotin compound and moisture, the silane groups are hydrolyzed to form silanols, and further condensation cross-linking bonds are formed;

[0042] After the modification treatment of the cross-linked modified plastic, sandblasting treatment is required, and the surface of the plastic is impacted by the abrasives ejected at high speed to form pits, so that the cementitious material fits more closely with the plastic aggregate;

[0043] The carbon nanotubes are polycarboxylic acid carbon nanotubes with a purity of 99%;

[0044] The silane coupling agent is a derivative of γ-aminopropyltriethoxysilane;

[0045] The preparation method of the zero-magnetic concrete is characterized in that the method specifically includes the following steps:

[0046] S1. Mix the non-magnetic cement and carbon nanotubes and stir evenly to obtain the gel material A, and the stirring time is not less than 2 minutes;

[0047] S2. Mix water, silane coupling agent and water reducing agent and stir evenly to obtain admixture B. Pour admixture B into gel material A, mix and stir evenly to obtain mixture C, and the stirring time is not less than 1 min.

[0048] S3. Pour the treated plastic aggregate into mixture C, mix and stir evenly to obtain modified plastic instead of aggregate zero-magnetic concrete, and the stirring time is not less than 2 min.

[0049] Example 1

[0050] A zero-magnetic concrete with modified plastic instead of aggregate, the zero-magnetic concrete includes non-magnetic cement, carbon nanotubes, crosslinked modified plastic, silane coupling agent, deionized water, water reducing agent, and the zero-magnetic concrete includes the following components by mass fraction:

[0051]

[0052] The fluidity of the non-magnetic concrete is 180 mm, the 28-day compressive strength is 52.3 Mpa, and the remanent magnetic strength is 3.6 nT.

[0053] Example 2

[0054] A zero-magnetic concrete with modified plastic instead of aggregate, the zero-magnetic concrete includes non-magnetic cement, carbon nanotubes, crosslinked modified plastic, silane coupling agent, deionized water, water reducing agent, and the zero-magnetic concrete includes the following components by mass fraction:

[0055]

[0056] The fluidity of the non-magnetic concrete is 195 mm, the 28-day compressive strength is 50.7 Mpa, and the remanent magnetic strength is 1.9 nT.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the invention or perform equivalent replacements for some technical features without departing from the spirit of the technical solutions of the present invention, and they should all be covered by the scope of the technical solutions claimed by the present invention.

Claims

1. A zero-magnetic concrete using a modified plastic instead of aggregate, characterized in that, The zero-magnetic concrete comprises non-magnetic cement, carbon nanotubes, cross-linked modified plastic, silane coupling agent, deionized water and a water reducer. The zero-magnetic concrete comprises the following components in weight percentage: 15.2-36.6% of non-magnetic cement, 0.5-2.0% of carbon nanotubes, 40.2-62.0% of cross-linked modified plastic, 0.05-0.1% of silane coupling agent, 8-20% of deionized water and 0.2-1.3% of the water reducer.

2. A zero-magnetic concrete using a modified plastic to replace aggregate according to claim 1, characterized in that The Fe content in the non-magnetic cement is less than 0.01%.

3. A zero-magnetic concrete using a modified plastic to replace aggregate according to claim 1, characterized in that, The cross-linked modified plastic is obtained by modifying ordinary polyethylene plastic. Specifically, silane and ordinary polyethylene plastic are treated with peroxide to generate silane-grafted polyethylene, and then the silane group is hydrolyzed to generate silanol under the action of an organic tin compound and water, and the cross-linking bonds are further condensed to obtain the cross-linked modified plastic.

4. A zero-magnetic concrete using a modified plastic to replace aggregate according to claim 1, characterized in that, The carbon nanotubes are multi-walled carbon nanotubes, and the purity of the carbon nanotubes is greater than 98%.

5. A zero-magnetic concrete using a modified plastic to replace aggregate according to claim 1, characterized in that, The silane coupling agent is a derivative of gamma-aminopropyltriethoxysilane or methacryloxypropyltrimethoxysilane.

6. A zero-magnetic concrete using a modified plastic to replace aggregate according to claim 1, characterized in that, The water reducer is a polycarboxylic acid water reducer, and the water reduction rate of the water reducer is ≥30%.

7. A method for preparing zero-magnetic concrete using modified plastics instead of aggregate, characterized in that: The method specifically comprises the following steps: S1, mixing non-magnetic cement and carbon nanotubes and stirring them uniformly to obtain gel material A, with the stirring time being not less than 2 minutes; S2, mixing deionized water, a silane coupling agent, and a water reducing agent and stirring uniformly to obtain an admixture B, pouring the admixture B into the gel material A, mixing and stirring uniformly to obtain a mixture C, with the stirring time being not less than 1 minute; S3, pouring the pretreated cross-linked modified plastic into the mixed material C and mixing and stirring evenly to obtain non-magnetic concrete, with the stirring time being no less than 2 minutes.

8. A method for preparing zero-magnetic concrete by using modified plastics to replace aggregates according to claim 7, characterized in that, The cross-linked modified plastic pretreatment is: the cross-linked modified plastic is sandblasted, and a high-speed abrasive is used to impact the plastic surface to form pits, so that the gelling material and the cross-linked modified plastic are more closely attached.

9. The preparation method of zero-magnetic concrete using modified plastics to replace aggregates according to claim 7, characterized in that, The fluidity of the non-magnetic concrete is greater than 160 mm, the 28-day compressive strength of the non-magnetic concrete is greater than 50 MPa, and the residual magnetic strength of the non-magnetic concrete is less than 5 nT.

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