Preparation method of SiC concrete with electromagnetic wave absorption function and concrete

Abstract

The invention relates to a preparation method of SiC concrete with an electromagnetic wave absorption function and concrete.The method comprises the steps that 1, fine aggregate, Portland cement, fly ash and coarse aggregate are evenly mixed to obtain powder, the fine aggregate comprises modified SiC and sand, the modified SiC accounts for 15% or less of the total mass of the concrete, and the sand accounts for 15% or less of the total mass of the concrete; wherein the modified SiC is obtained by modifying a silane coupling agent; step 2, adding a water reducing agent into water, dissolving to obtain a water reducing agent aqueous solution, and uniformly mixing the powder with the water reducing agent aqueous solution in a stirring state to obtain a wave-absorbing concrete stirring material; and step 3, pouring the wave-absorbing concrete mixed material obtained in the step 2 into a mold for pouring, vibrating and molding, and maintaining for 28 days to obtain the SiC wave-absorbing concrete. The SiC concrete with the electromagnetic wave absorption function has good electromagnetic wave absorption performance, wave absorption strength and effective frequency band width; the strength of the concrete is guaranteed, and meanwhile, the mechanical property of the concrete can be improved.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to a method for preparing SiC concrete with electromagnetic wave absorption function and concrete. Background Art

[0002] The widespread use of electronic and electrical equipment leads to the problem of electromagnetic radiation, which may not only affect human health but also interfere with the normal operation of precision instruments and may even lead to the leakage of electromagnetic information. For some places with confidentiality requirements, the leakage of electromagnetic information may lead to serious adverse consequences.

[0003] In order to weaken or absorb electromagnetic waves, the existing technology adopts the method of adding carbon fillers such as CNT, carbon fiber, nano carbon fiber, etc. to concrete. In addition, metal materials such as carbonyl iron powder are also added. However, oxidation reaction will occur on the surface of metal materials, thereby reducing the electromagnetic absorption performance of concrete and also affecting the strength and toughness of the concrete itself.

[0004] As an absorbing material with excellent dielectric properties, SiC has the advantages of stability, high strength and corrosion resistance, but it has the disadvantages of poor impedance matching and a single absorbing mechanism (Xing Yuanming, Yang Tao, Wang Enhui, Liu Cheng, Hou Xinmei. Research and development of SiC composite absorbing materials. Journal of Composite Materials. Issue 9, 2023).

[0005] In addition, SiC directly used in concrete has problems with poor dispersion and fluidity, and is prone to agglomeration, which is not conducive to the strength of concrete. Summary of the invention

[0006] In order to improve the wave absorbing performance and solve the problems of poor dispersion and fluidity when SiC is used to prepare concrete, the present invention provides a method for preparing SiC concrete and concrete with electromagnetic wave absorption function, which solves the problems of poor dispersion and fluidity of SiC by modifying SiC, improves the strength of concrete and improves the wave absorbing performance at the same time.

[0007] The technical objectives of the present invention are achieved through the following technical solutions:

[0008] A method for preparing SiC concrete with electromagnetic wave absorption function, the method comprising:

[0009] Step 1, fine aggregate, silicate cement, fly ash and coarse aggregate are uniformly mixed to obtain powder, the fine aggregate includes modified SiC and sand, the modified SiC accounts for less than or equal to 15% of the total mass of concrete, and the modified SiC is modified by a silane coupling agent;

[0010] Step 2, adding a water reducer into water to dissolve to obtain a water reducer aqueous solution, and mixing the powder and the water reducer aqueous solution evenly under stirring to obtain a wave-absorbing concrete mixing material;

[0011] Step 3: Pour the mixed material of the absorbing concrete obtained in step 2 into a mold for casting, vibrate and shape it, and then maintain it for 28 days to obtain the SiC absorbing concrete.

[0012] Further, when preparing the modified SiC by using a silane coupling agent, the following steps are included:

[0013] Step 1.1, preparing a silane coupling agent solution: adding a silane coupling agent dropwise to an acetic acid aqueous solution having a concentration of 0.2%, stirring the acetic acid aqueous solution continuously during the dropping process, and the concentration of the silane coupling agent solution is 0.8%-1.2%;

[0014] Step 1.2, after the silane coupling agent is added dropwise, continue stirring for 30-60 minutes and then add SiC and stir evenly;

[0015] Step 1.3, filter and dry to obtain modified SiC.

[0016] Furthermore, the silane coupling agent is industrial grade silane coupling agent KH-550, with a molecular formula of C 9 H 23 O 3 NSi, structural formula is H 2 N-CH 2 CH 2 CH 2 -Si(OC 2 H 5 ) 3 , active ingredient content ≥98%.

[0017] Furthermore, according to the mass ratio, 228-289 parts of silicate cement, 150-200 parts of fly ash, 462-612 parts of fine aggregate, 1050-1200 parts of coarse aggregate, 170-220 parts of water, and 2.4-3.2 parts of water reducer are taken.

[0018] Furthermore, according to the mass fraction ratio, 250 parts of silicate cement, 180 parts of fly ash, 570 parts of fine aggregate, 1100 parts of coarse aggregate, 200 parts of water, and 2.8 parts of water reducer are taken.

[0019] Furthermore, the modified SiC accounts for 4%-10% of the total mass of the concrete.

[0020] Furthermore, the SiC is industrial 36 mesh black SiC with a mass content greater than 95%.

[0021] Furthermore, the water reducing agent is a polycarboxylic acid type water reducing agent, with a water reducing rate of >25%, a solid content of 24%, and a density of 1020-1080 kg / m 3 .

[0022] The present invention also provides a SiC concrete with electromagnetic wave absorption function, which comprises 228-289 parts of silicate cement, 150-200 parts of fly ash, 462-612 parts of fine aggregate, 1050-1200 parts of coarse aggregate, 170-220 parts of water, and 2.4-3.2 parts of water reducer according to the mass ratio, wherein the fine aggregate comprises modified SiC and sand, the modified SiC is obtained by modification with a silane coupling agent, and the modified SiC accounts for between 4% and 10% of the total mass ratio of the concrete.

[0023] Furthermore, the above-mentioned SiC concrete with electromagnetic wave absorption function is prepared by the above-mentioned preparation method.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The SiC concrete with electromagnetic wave absorption function of the present invention has good electromagnetic wave absorption performance, and its absorption intensity and effective frequency band width are better than most absorbing concrete systems;

[0026] 2. Using modified SiC as part of fine aggregate can not only ensure the strength of concrete, but also improve the mechanical properties of concrete.

[0027] 3. The raw materials of the SiC concrete with electromagnetic wave absorption function of the present invention are all industrial raw materials, the preparation cost is relatively low, and the preparation method is simple, and industrial production can be quickly realized. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0029] Example 1

[0030] A SiC concrete with electromagnetic wave absorption function includes 228-289 parts of silicate cement, 150-200 parts of fly ash, 462-612 parts of fine aggregate, 1050-1200 parts of coarse aggregate, 170-220 parts of water, and 2.4-3.2 parts of water reducer according to the mass ratio, wherein the fine aggregate includes modified SiC and sand, the modified SiC is obtained by modification with a silane coupling agent, and the modified SiC accounts for 4%-10% of the total mass ratio of the concrete. By using the modified SiC instead of part of the sand as the fine aggregate, the concrete strength and mechanical properties can be increased while absorbing the waves.

[0031] More specifically, the SiC is industrial 36 mesh black SiC with a mass content greater than 95%. The water reducer is a polycarboxylic acid type water reducer with a water reduction rate of more than 25%, a solid content of 24%, and a density of 1020-1080 kg / m 3 The strength grade of silicate cement is P.Ⅱ52.5, the specific surface area is 455㎡ / kg, and the apparent density is 3050kg / m 3 , bulk density is 1250kg / m 3 The fly ash is Class II F fly ash.

[0032] Example 2

[0033] A method for preparing SiC concrete with electromagnetic wave absorption function, the method comprising:

[0034] Step 1: Take 570 parts of fine aggregate, 250 parts of Portland cement, 180 parts of fly ash, 1100 parts of coarse aggregate, 200 parts of water and 2.8 parts of water reducer according to the mass ratio;

[0035] The fine aggregate, silicate cement, fly ash and coarse aggregate are uniformly mixed to obtain powder, wherein the fine aggregate includes modified SiC and sand, the modified SiC is obtained by modifying the silane coupling agent, and the modified SiC accounts for less than or equal to 15% of the total mass of the concrete; the coarse aggregate is selected from stones;

[0036] Step 2, adding a water reducer into water to dissolve to obtain a water reducer aqueous solution, and mixing the powder and the water reducer aqueous solution evenly under stirring to obtain a wave-absorbing concrete mixing material;

[0037] Step 3: Pour the mixed material of the absorbing concrete obtained in step 2 into a mold for casting, vibrate and shape it, and then maintain it for 28 days to obtain the SiC absorbing concrete.

[0038] Preferably, the modified SiC accounts for 4%-10% of the total mass ratio of concrete. In this embodiment, 7 groups of modified SiC accounts for the total mass ratio of concrete, and 1 group of unmodified SiC accounts for the total mass ratio of concrete, a total of 8 groups are provided for illustration, the modified SiC accounts for 0%, 2%, 4%, 6%, 8%, 10% and 12% of the total mass ratio of concrete, respectively, and the unmodified SiC accounts for 8% of the mass of concrete. The mass fractions of each component are shown in the following table:

[0039]

[0040]

[0041] The above eight groups of concrete were subjected to performance tests, and the test data are shown in the following table:

[0042]

[0043]

[0044] The wave absorbing performance of the above 8 groups of concrete was tested, and the test results are shown in the following table:

[0045]

[0046]

[0047] Example 3

[0048] Step 1: Take 612 parts of fine aggregate, 228 parts of Portland cement, 200 parts of fly ash, 1050 parts of coarse aggregate, 228 parts of water and 2.4 parts of water reducer according to the mass ratio;

[0049] The fine aggregate, silicate cement, fly ash and coarse aggregate are uniformly mixed to obtain powder, wherein the fine aggregate includes modified SiC and sand, the modified SiC is obtained by modifying the silane coupling agent, and the modified SiC accounts for less than or equal to 15% of the total mass of the concrete; the coarse aggregate is selected from stones;

[0050] Step 2, adding a water reducer into water to dissolve to obtain a water reducer aqueous solution, and mixing the powder and the water reducer aqueous solution evenly under stirring to obtain a wave-absorbing concrete mixing material;

[0051] Step 3: Pour the mixed material of the absorbing concrete obtained in step 2 into a mold for casting, vibrate and shape it, and then maintain it for 28 days to obtain the SiC absorbing concrete.

[0052] Preferably, the modified SiC accounts for 4%-10% of the total mass ratio of concrete. In this embodiment, 7 groups of modified SiC accounts for the total mass ratio of concrete, and 1 group of unmodified SiC accounts for the total mass ratio of concrete, a total of 8 groups are provided for illustration, the modified SiC accounts for 0%, 2%, 4%, 6%, 8%, 10% and 12% of the total mass ratio of concrete, respectively, and the unmodified SiC accounts for 8% of the mass of concrete. The mass fractions of each component are shown in the following table:

[0053]

[0054]

[0055] The above eight groups of concrete were subjected to performance tests, and the test data are shown in the following table:

[0056]

[0057]

[0058] The wave absorbing performance of the above 8 groups of concrete was tested, and the test results are shown in the following table:

[0059]

[0060]

[0061] Example 4

[0062] Step 1: Take 462 parts of fine aggregate, 289 parts of Portland cement, 150 parts of fly ash, 1200 parts of coarse aggregate, 170 parts of water and 3.2 parts of water reducer according to the mass ratio;

[0063] The fine aggregate, silicate cement, fly ash and coarse aggregate are uniformly mixed to obtain powder, wherein the fine aggregate includes modified SiC and sand, the modified SiC is obtained by modifying the silane coupling agent, and the modified SiC accounts for less than or equal to 15% of the total mass of the concrete; the coarse aggregate is selected from stones;

[0064] Step 2, adding a water reducer into water to dissolve to obtain a water reducer aqueous solution, and mixing the powder and the water reducer aqueous solution evenly under stirring to obtain a wave-absorbing concrete mixing material;

[0065] Step 3: Pour the mixed material of the absorbing concrete obtained in step 2 into a mold for casting, vibrate and shape it, and then maintain it for 28 days to obtain the SiC absorbing concrete.

[0066] Preferably, the modified SiC accounts for 4%-10% of the total mass ratio of concrete. In this embodiment, 7 groups of modified SiC accounts for the total mass ratio of concrete, and 1 group of unmodified SiC accounts for the total mass ratio of concrete, a total of 8 groups are provided for illustration, the modified SiC accounts for 0%, 2%, 4%, 6%, 8%, 10% and 12% of the total mass ratio of concrete, respectively, and the unmodified SiC accounts for 8% of the mass of concrete. The mass fractions of each component are shown in the following table:

[0067]

[0068]

[0069] The above eight groups of concrete were subjected to performance tests, and the test data are shown in the following table:

[0070]

[0071]

[0072] The wave absorbing performance of the above eight groups of concrete was tested, and the test results are shown in the following table:

[0073]

[0074]

[0075] Through the comparison of 24 groups of concrete in the above three embodiments 2-4, both unmodified SiC and modified SiC can improve the wave absorption strength and effective bandwidth of concrete, and the modified SiC has better effect. It can be seen that when the content of modified SiC accounts for 4%-10% of the total mass ratio of concrete, the wave absorption performance of concrete is excellent, and its wave absorption strength and effective bandwidth are relatively good; when the content of modified SiC accounts for 12% of the total mass ratio of concrete, although the wave absorption strength and effective bandwidth of concrete continue to increase, the strength of concrete decreases, and the cost of adding modified SiC also increases accordingly. Modified SiC is obtained by modifying SiC, so that the fluidity and dispersibility of SiC are improved, and SiC is prevented from forming agglomeration structure, so that SiC can be evenly dispersed in concrete, thereby changing the overall dielectric constant of concrete, and more electromagnetic waves are converted into heat energy and consumed when passing through concrete, thereby weakening the propagation of electromagnetic waves and increasing the absorption of electromagnetic waves. Compared with adding conventional absorbing materials to concrete, such as adding carbon black absorbing materials to concrete, although it has a certain absorbing effect, the addition of carbon black will have a negative effect on the compressive strength of concrete, reducing the compressive strength of concrete. By adding modified SiC to replace part of the sand as fine aggregate, since SiC has relatively large hardness, relatively high strength, and does not absorb water, it has a positive effect on the compressive strength of concrete after addition, thereby improving the compressive strength of concrete.

[0076] Example 5

[0077] This embodiment provides a process for preparing modified SiC by using a silane coupling agent, comprising the following steps:

[0078] Step 1.1: Prepare a silane coupling agent solution: add a silane coupling agent dropwise to a 0.2% acetic acid aqueous solution, stirring the acetic acid aqueous solution continuously during the addition process, and the concentration of the silane coupling agent solution is 0.8%-1.2%; wherein the silane coupling agent is an industrial grade silane coupling agent KH-550, with a molecular formula of C 9 H 23 O 3 NSi, structural formula is H 2 N-CH 2 CH 2 CH 2 -Si(OC 2 H 5 ) 3 , active ingredient content ≥98%.

[0079] Step 1.2, after the silane coupling agent is added dropwise, continue stirring for 30-60 minutes and then add SiC and stir evenly;

[0080] Step 1.3, filter and dry to obtain modified SiC. Acetic acid can promote the accelerated decomposition of the silane coupling agent and improve the stability of silanol. The strength, wear resistance and dispersibility of the modified SiC obtained by the modification of the silane coupling agent are improved compared with the SiC before modification.

[0081] This embodiment is only a further explanation of the present invention, not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it will be protected by the patent law.

Claims

1. A method for preparing SiC concrete with electromagnetic wave absorption function, characterized in that: The method includes: Step 1, fine aggregate, silicate cement, fly ash and coarse aggregate are uniformly mixed to obtain powder, the fine aggregate includes modified SiC and sand, the modified SiC accounts for less than or equal to 15% of the total mass of concrete, and the modified SiC is obtained by modification with a silane coupling agent; Step 2, adding a water reducer into water to dissolve to obtain a water reducer aqueous solution, and mixing the powder and the water reducer aqueous solution evenly under stirring to obtain a wave-absorbing concrete mixing material; Step 3: Pour the mixed material of the absorbing concrete obtained in step 2 into a mold for casting, vibrate and shape it, and then maintain it for 28 days to obtain SiC absorbing concrete.

2. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 1, characterized in that: When preparing modified SiC by using a silane coupling agent, the following steps are included: Step 1.1, preparing a silane coupling agent solution: adding a silane coupling agent dropwise to an acetic acid aqueous solution having a concentration of 0.2%, stirring the acetic acid aqueous solution continuously during the dropping process, and the concentration of the silane coupling agent solution is 0.8%-1.2%; Step 1.2, after the silane coupling agent is added dropwise, continue stirring for 30-60 minutes and then add SiC and stir evenly; Step 1.3, filter and dry to obtain modified SiC.

3. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 2, characterized in that: The silane coupling agent is industrial grade silane coupling agent KH-550, with a molecular formula of C9H 23 O3NSi, the structural formula is H2N-CH2CH2CH2-Si(OC2H5)3, and the active ingredient content is ≥98%.

4. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 1, characterized in that: According to the mass ratio, take 228-289 parts of silicate cement, 150-200 parts of fly ash, 462-612 parts of fine aggregate, 1050-1200 parts of coarse aggregate, 170-220 parts of water, and 2.4-3.2 parts of water reducer.

5. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 4, characterized in that: According to the mass fraction ratio, take 250 parts of silicate cement, 180 parts of fly ash, 570 parts of fine aggregate, 1100 parts of coarse aggregate, 200 parts of water and 2.8 parts of water reducer.

6. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 4, characterized in that: The modified SiC accounts for 4%-10% of the total mass of the concrete.

7. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 1, characterized in that: The SiC is industrial 36 mesh black SiC with a mass content greater than 95%.

8. The method for preparing SiC concrete with electromagnetic wave absorption function according to claim 1, characterized in that: The water reducer is a polycarboxylic acid type water reducer with a water reduction rate of >25%, a solid content of 24%, and a density of 1020-1080 kg / m 3 .

9. A SiC concrete with electromagnetic wave absorption function, characterized in that: The concrete comprises 228-289 parts of silicate cement, 150-200 parts of fly ash, 462-612 parts of fine aggregate, 1050-1200 parts of coarse aggregate, 170-220 parts of water and 2.4-3.2 parts of water reducer in terms of mass ratio, wherein the fine aggregate comprises modified SiC and sand, the modified SiC is obtained by modification with a silane coupling agent, and the modified SiC accounts for 4%-10% of the total mass ratio of the concrete.

10. The SiC concrete with electromagnetic wave absorption function according to claim 9, characterized in that: The SiC concrete is prepared according to the method according to any one of claims 1 to 3.

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