Seawater-corrosion-resistant foam concrete with superfine closed-cell structure as well as preparation method and application of seawater-corrosion-resistant foam concrete

Abstract

The invention relates to seawater corrosion resistant foam concrete with a superfine closed-cell structure as well as a preparation method and application of the seawater corrosion resistant foam concrete. The seawater corrosion-resistant foam concrete with the superfine closed-cell structure comprises the following components: slurry and foam, the slurry comprises the following components: cement and water; wherein the foam has a core-shell structure, and the core-shell structure comprises a hollow core formed by nanoparticles, a chitosan-silane coupling agent molecular chain and a polyacrylamide-silane coupling agent molecular chain which are grafted to the surfaces of the nanoparticles, and a surfactant molecular chain attached to the inner side. According to the present invention, the foam stability and the dispersion effect are strong, the fine closed pores can be formed after the foam is mixed with the cement slurry, the mechanical strength, the acid-base resistance, the seawater resistance and other properties of the product are effectively improved, the service life is long, and the important significance is provided for the further promotion and application of the superfine closed pore foam concrete.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to an ultra-fine closed-cell structure seawater erosion-resistant foam concrete and a preparation method and application thereof. Background Art

[0002] Foam concrete is a lightweight concrete material with a porous structure. It has good load reduction, heat insulation, sound insulation, earthquake resistance and other functions. At the same time, it has fast construction speed and low cost. It has been widely used in many fields.

[0003] Compared with conventional foam concrete, ultrafine closed-cell foam concrete has a finer pore structure, so it has a lower density and has more obvious advantages of being lightweight and high-strength. In addition, the smaller the pores, the more noise they can absorb, the lower the thermal conductivity, and the higher the strength they can achieve. In addition, ultrafine closed-cell foam concrete reduces the amount of cement used and can act on composite solid waste, which is in line with my country's policy requirements for carbon reduction and emission reduction and industrial closed-loop.

[0004] Although ultrafine closed-cell foam concrete is favored due to its many advantages, there are still some defects in the existing products of this type. For example, the stability of conventional ultrafine foam concrete is relatively low, especially in the application of coastal roads and bridges. Some materials are in a state of soaking in water for a long time. Conventional foam concrete has a high water absorption rate and obvious softening after water absorption, and its durability is poor. The application effect in coastal roads and bridges is not ideal; at the same time, the foam concrete in roads and bridges has a lower lifespan due to long-term outdoor exposure to multiple factors such as dry-wet cycles, sulfate erosion, and dynamic loads, and may experience cracking, fracture, erosion, pulverization, softening, etc.; in addition, after mixing cement and other materials with foam, the stability of the foam is poor, which will lead to large pore size, low closed-loop rate, uneven distribution, etc., which ultimately affects the durability of foam concrete in roads and bridges, especially in coastal areas.

[0005] Therefore, it is urgent to develop a new technical solution to solve the problems existing in the prior art. Summary of the invention

[0006] Based on this, the present invention provides an ultra-fine closed-cell structure seawater erosion resistant foam concrete and its preparation method and application. The present invention uses chitosan, acrylamide and silane coupling agent and other components to react and compound with surfactants and nanoparticles to obtain foam, which has strong stability and dispersion effect. After mixing with cement slurry, it can form smaller closed pores, effectively improve the mechanical strength, acid and alkali resistance, seawater resistance and other properties of the product, and at the same time, it has a longer service life, which is of great significance for the further promotion and application of ultra-fine closed-cell foam concrete.

[0007] One object of the present invention is to provide a superfine closed-cell structure seawater erosion resistant foam concrete, wherein the bulk density of the superfine closed-cell structure seawater erosion resistant foam concrete is 300-1500kg / m 3 ,

[0008] The ultra-fine closed-cell structure seawater erosion resistant foamed concrete comprises the following components in parts by mass:

[0009] Slurry 91.6-99.7 parts

[0010] Foam 0.3-8.4 parts;

[0011] The slurry includes the following components in parts by weight:

[0012] 90-100 parts of cement

[0013] water;

[0014] in,

[0015] The foam has a core-shell structure, which includes a hollow core formed by oxide nanoparticles, chitosan-silane coupling agent molecular chains and polyacrylamide-silane coupling agent molecular chains grafted on the surface of the oxide nanoparticles, and surfactant molecular chains attached to the inside.

[0016] Furthermore, the foam comprises the following components in parts by weight:

[0017] Intermediate product 0.05-0.5 parts

[0018] Surfactant 9-10 parts

[0019] Reactive thickener 0.1-1 part

[0020] water;

[0021] The intermediate product comprises the following components by weight:

[0022] Silane coupling agent solution 10-15 parts

[0023] 10-20 parts of oxide nanoparticles;

[0024] The reactive thickener comprises chitosan, acrylamide and an auxiliary agent.

[0025] Furthermore, the silane coupling agent includes an epoxy silane coupling agent and an acryloxy silane coupling agent.

[0026] Furthermore, the oxide nanoparticles are selected from one or more of aluminum oxide, zinc oxide, silicon dioxide, and titanium dioxide.

[0027] Furthermore, the auxiliary agent is selected from one or more of hydroxypropyl cellulose, carboxymethyl cellulose, polyethylene glycol distearate, coconut oil fatty acid diethanolamide, pregelatinized starch, and a photoinitiator.

[0028] Furthermore, the content of the photoinitiator is 0.1-1 mol % of acrylamide.

[0029] Furthermore, the photoinitiator is a water-soluble photoinitiator.

[0030] Further, the surfactant includes anionic surfactant and nonionic surfactant;

[0031] The anionic surfactant is selected from one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, nonylphenol sulfonate, and sodium stearate;

[0032] The nonionic surfactant is selected from one or more of nonylphenol polyoxyethylene ether, polyoxyethylene fatty acid ester, and alkyl alcohol polyoxyethylene ether.

[0033] Furthermore, the mass of the chitosan and acrylamide is 30-50wt% of the reactive thickener.

[0034] Furthermore, the slurry also includes auxiliary materials and / or zinc stearate and / or a water reducing agent.

[0035] Furthermore, the auxiliary material is selected from one or both of fly ash and silica ash.

[0036] Another object of the present invention is to provide a method for preparing the above-mentioned ultra-fine closed-cell structure seawater erosion-resistant foamed concrete, the method for preparing the ultra-fine closed-cell structure seawater erosion-resistant foamed concrete comprising the following steps:

[0037] S1, mixing a silane coupling agent solution and oxide nanoparticles, stirring for reaction, and drying to obtain an intermediate product;

[0038] S2, mixing the intermediate product, a surfactant, a reactive thickener and water to obtain a foaming liquid;

[0039] S3, foaming the foaming liquid, and then irradiating it with ultraviolet light to obtain foam;

[0040] S4, mixing cement and water to obtain slurry;

[0041] S5. Mixing the foam and slurry to obtain ultra-fine closed-cell foam concrete resistant to seawater erosion.

[0042] Furthermore, the density of the foam is 25-30 g / L.

[0043] Furthermore, the water-cement ratio of the slurry is 0.45-0.65.

[0044] Furthermore, in step S2, the mass ratio of the intermediate product, the surfactant, the reactive thickener to water is 0.3:(90-110).

[0045] Furthermore, the ultraviolet light irradiation is: using a UV irradiation reaction with a wavelength of 365nm and an irradiation intensity of >200mW / m 2 , <500mW / m 2 The irradiation reaction time is 5-30s.

[0046] Furthermore, in step S5, the mixing adopts an SK type static mixer, and the mixing efficiency is ≥90%.

[0047] Another object of the present invention is to provide an application of the ultra-fine closed-cell structure seawater erosion-resistant foamed concrete in the construction of roads and bridges in coastal areas, comprising the following steps:

[0048] L1. Construction preparation;

[0049] L2, clear the accumulated water;

[0050] L3, the formwork separates the working surface;

[0051] L4, foam concrete pumping;

[0052] L5, finishing;

[0053] L6. Maintenance.

[0054] The present invention has the following beneficial effects:

[0055] The invention provides a seawater erosion resistant foam concrete with an ultrafine closed-cell structure. The foam with a specific structure is compounded with cement slurry. The foam firstly reacts epoxy silane coupling agent and acryloxy silane coupling agent with oxide nanoparticles to obtain an intermediate product with epoxy groups and double bonds on the surface, and chitosan and acrylamide are used as reactive thickener components. Then, the intermediate product is reacted with components such as thickeners and surfactants. On the one hand, chitosan and the epoxy groups of the intermediate product are cross-linked, and on the other hand, acrylamide and the intermediate product are polymerized to form an organic polymer shell layer, thereby obtaining Pickering bubbles. The inner wall of the bubble is composed of oxide nanoparticles, anionic and nonionic surfactant segments are attached, the bubble has high tolerance to extreme environments such as strong alkalinity, and is not prone to defoaming when pH changes. At the same time, the surface of the oxide nanoparticles is also coated with chitosan and polyacrylamide macromolecular segments, and multiple components synergistically enhance the effect to form a solid reinforcement layer shell. After the bubbles are mixed with the slurry, more closed pores can be generated, and the foam pore size is also smaller, which not only improves the (sea) water resistance and stability of the foam concrete, but also improves the defects of excessive pore size and uneven distribution, and greatly improves the mechanical properties of the concrete. In summary, the ultra-fine closed-cell structure seawater erosion resistant foam concrete of the present invention overcomes the defects existing in the prior art and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A schematic diagram of the foam structure of the present invention is shown.

[0057] Figure numerals: 1-surfactant; 2-oxide nanoparticles; 3-chitosan-silane coupling agent molecular chain; 4-polyacrylamide-silane coupling agent molecular chain. DETAILED DESCRIPTION

[0058] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0059] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0060] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0061] The photoinitiator in the embodiment of the present invention is 2959.

[0062] The alkyl alcohol polyoxyethylene ether in the embodiment of the present invention is AEO-9.

[0063] The "parts" in the embodiments of the present invention refer to parts by mass.

[0064] Example 1

[0065] An ultra-fine closed-cell structure seawater erosion-resistant foamed concrete comprises the following components in parts by mass:

[0066] Slurry 97.9 parts

[0067] Foam 2.1 parts;

[0068] The slurry includes the following components in parts by weight:

[0069] 100 parts cement

[0070] Water 58 parts;

[0071] The foam comprises the following components in parts by weight:

[0072]

[0073] The intermediate product comprises the following components by weight:

[0074] Silane coupling agent solution 10.3 parts

[0075] 15 parts of oxide nanoparticles;

[0076] The method for preparing the ultrafine closed-cell structure seawater erosion-resistant foamed concrete comprises the following steps:

[0077] S1. Add 15g KH-560 and 15g KH-570 to 1kg 95% ethanol, then add 1.5kg nano-alumina, stir and react for 2h, filter, and dry at 60°C to obtain an intermediate product;

[0078] S2, 15g chitosan, 15g acrylamide, 30g hydroxypropyl cellulose and a photoinitiator are mixed (the amount of the photoinitiator added is 0.002mol) to obtain a reactive thickener;

[0079] 10 g of the intermediate product, 990 g of a surfactant (nonylphenol sulfonate and alkyl alcohol polyoxyethylene ether in a mass ratio of 1:1) and the reactive thickener were mixed, and then 100 kg of water was added, and the mixture was mixed and stirred to obtain a foaming liquid;

[0080] S3, the foaming liquid is foamed by a foaming machine, and then 2 Irradiate with UV for 20s to obtain a foam with a density of 28g / L;

[0081] S4, mixing cement and water at a water-cement ratio of 0.58 to obtain a slurry;

[0082] S5, the foam and slurry are mixed by SK type static mixer to obtain a bulk density of 800kg / m 3 Ultra-fine closed-cell foam concrete resistant to seawater erosion.

[0083] Figure 1 A schematic diagram of the foam structure of the present invention is shown.

[0084] Figure numerals: 1-surfactant; 2-oxide nanoparticles; 3-chitosan-silane coupling agent molecular chain; 4-polyacrylamide-silane coupling agent molecular chain.

[0085] Example 2

[0086] An ultra-fine closed-cell structure seawater erosion-resistant foamed concrete comprises the following components in parts by mass:

[0087] Slurry 96.7 parts

[0088] Foam 3.3 parts;

[0089] The slurry includes the following components in parts by weight:

[0090] 100 parts cement

[0091] Water 58 parts;

[0092] The foam comprises the following components in parts by weight:

[0093]

[0094] The intermediate product comprises the following components by weight:

[0095] Silane coupling agent solution 10.3 parts

[0096] 15 parts of oxide nanoparticles;

[0097] The method for preparing the ultrafine closed-cell structure seawater erosion-resistant foamed concrete comprises the following steps:

[0098] S1. Add 15g KH-560 and 15g KH-570 to 1kg 95% ethanol, then add 1.5kg nano-alumina, stir and react for 2h, filter, and dry at 60°C to obtain an intermediate product;

[0099] S2, 15g chitosan, 15g acrylamide, 30g hydroxypropyl cellulose and a photoinitiator are mixed (the amount of the photoinitiator added is 0.002mol) to obtain a reactive thickener;

[0100] 10 g of the intermediate product, 990 g of a surfactant (nonylphenol sulfonate and alkyl alcohol polyoxyethylene ether in a mass ratio of 1:1) and the reactive thickener were mixed, and then 100 kg of water was added, and the mixture was mixed and stirred to obtain a foaming liquid;

[0101] S3, the foaming liquid is foamed by a foaming machine, and then 2 Irradiate with UV for 20s to obtain a foam with a density of 28g / L;

[0102] S4, mixing cement and water at a water-cement ratio of 0.58 to obtain a slurry;

[0103] S5, the foam and slurry are mixed by SK type static mixer to obtain a bulk density of 600kg / m 3 Ultra-fine closed-cell foam concrete resistant to seawater erosion.

[0104] Example 3

[0105] An ultra-fine closed-cell structure seawater erosion-resistant foamed concrete comprises the following components in parts by mass:

[0106] Slurry 95.6 parts

[0107] Foam 4.4 parts;

[0108] The slurry includes the following components in parts by weight:

[0109] 100 parts cement

[0110] Water 58 parts;

[0111] The foam comprises the following components in parts by weight:

[0112]

[0113] The intermediate product comprises the following components by weight:

[0114] Silane coupling agent solution 10.3 parts

[0115] 15 parts of oxide nanoparticles;

[0116] The method for preparing the ultrafine closed-cell structure seawater erosion-resistant foamed concrete comprises the following steps:

[0117] S1. Add 15g KH-560 and 15g KH-570 to 1kg 95% ethanol, then add 1.5kg nano-alumina, stir and react for 2h, filter, and dry at 60°C to obtain an intermediate product;

[0118] S2, 15g chitosan, 15g acrylamide, 30g hydroxypropyl cellulose and a photoinitiator are mixed (the amount of the photoinitiator added is 0.002mol) to obtain a reactive thickener;

[0119] 10 g of the intermediate product, 990 g of a surfactant (nonylphenol sulfonate and alkyl alcohol polyoxyethylene ether in a mass ratio of 1:1) and the reactive thickener were mixed, and then 100 kg of water was added, and the mixture was mixed and stirred to obtain a foaming liquid;

[0120] S3, the foaming liquid is foamed by a foaming machine, and then 2 Irradiate with UV for 20s to obtain a foam with a density of 28g / L;

[0121] S4, mixing cement and water at a water-cement ratio of 0.58 to obtain a slurry;

[0122] S5, the foam and slurry are mixed by SK type static mixer to obtain a bulk density of 500kg / m 3 Ultra-fine closed-cell foam concrete resistant to seawater erosion.

[0123] Comparative Example 1

[0124] The difference between this comparative example and Example 1 is that acrylamide is replaced with methyl acrylate of equal mass, and other components and preparation methods are the same as those in Example 1.

[0125] The sample of Comparative Example 1 suffered from severe defoaming.

[0126] Comparative Example 2

[0127] The difference between this comparative example and Example 1 is that chitosan is replaced by cellulose of equal mass, and other components and preparation methods are the same as those in Example 1.

[0128] Test Case

[0129] Test method:

[0130] The foamed concrete prepared in the embodiment and comparative example and the commercially available product were applied to a road in Zhuhai. After the construction was completed, core sampling and on-site sample retention were performed, and post-base testing was performed to obtain test results.

[0131] Among them, the erosion resistance is to soak the concrete in artificial seawater (about 5 times the concentration of natural seawater) for 120 days after standard curing for 28 days, and then measure the compressive strength and calculate the decrease rate compared with the initial compressive strength.

[0132] The test results are shown in Table 1.

[0133] Table 1 Performance test results

[0134]

[0135] According to Table 1, it can be concluded that the ultra-fine closed-cell structure seawater erosion resistant foam concrete prepared in the embodiment of the present invention has the characteristics of light weight and high strength, and its compressive strength is better than that of commercially available products and comparative examples, and its closed-cell rate is also significantly larger. At the same time, it also has a small bubble structure. Since the embodiment has a more ideal porous structure, its water absorption rate is lower, and its erosion resistance is also more excellent. After long-term seawater immersion, the strength loss is significantly smaller. Therefore, the ultra-fine closed-cell structure seawater erosion resistant foam concrete of the present invention has both stronger performance and longer service life while effectively saving cement consumption, and has good application prospects.

[0136] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0137] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An ultra-fine closed-cell structure seawater erosion resistant foam concrete, characterized in that: The bulk density of the ultra-fine closed-cell structure seawater erosion resistant foam concrete is 300-1500kg / m 3 , The ultra-fine closed-cell structure seawater erosion resistant foamed concrete comprises the following components in parts by mass: Slurry 91.6-99.7 parts Foam 0.3-8.4 parts; The slurry includes the following components in parts by weight: 90-100 parts of cement water; in, The foam has a core-shell structure, which includes a hollow core formed by oxide nanoparticles, chitosan-silane coupling agent molecular chains and polyacrylamide-silane coupling agent molecular chains grafted on the surface of the oxide nanoparticles, and surfactant molecular chains attached to the inside.

2. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 1, characterized in that: The foam comprises the following components in parts by weight: Intermediate product 0.05-0.5 parts Surfactant 9-10 parts Reactive thickener 0.1-1 part water; The intermediate product comprises the following components by weight: Silane coupling agent solution 10-15 parts 10-20 parts of oxide nanoparticles; The reactive thickener comprises chitosan, acrylamide and an auxiliary agent.

3. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 2, characterized in that: The silane coupling agent includes an epoxy silane coupling agent and an acryloxy silane coupling agent.

4. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 2, characterized in that: The oxide nanoparticles are selected from one or more of aluminum oxide, zinc oxide, silicon dioxide and titanium dioxide.

5. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 2, characterized in that: The auxiliary agent is selected from one or more of hydroxypropyl cellulose, carboxymethyl cellulose, polyethylene glycol distearate, coconut oil fatty acid diethanolamide, pregelatinized starch, and a photoinitiator.

6. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 2, characterized in that: The surfactant includes anionic surfactant and nonionic surfactant; The anionic surfactant is selected from one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, nonylphenol sulfonate, and sodium stearate; The nonionic surfactant is selected from one or more of nonylphenol polyoxyethylene ether, polyoxyethylene fatty acid ester, and alkyl alcohol polyoxyethylene ether.

7. The ultra-fine closed-cell structure seawater erosion resistant foamed concrete according to claim 2, characterized in that: The mass of the chitosan and acrylamide is 30-50wt% of the reactive thickener.

8. The method for preparing the ultrafine closed-cell structure seawater erosion resistant foamed concrete according to any one of claims 1 to 7, characterized in that: The method for preparing the ultrafine closed-cell structure seawater erosion-resistant foamed concrete comprises the following steps: S1, mixing a silane coupling agent solution and oxide nanoparticles, stirring for reaction, and drying to obtain an intermediate product; S2, mixing the intermediate product, a surfactant, a reactive thickener and water to obtain a foaming liquid; S3, foaming the foaming liquid, and then irradiating it with ultraviolet light to obtain foam; S4, mixing cement and water to obtain slurry; S5. Mixing the foam and slurry to obtain ultra-fine closed-cell foam concrete resistant to seawater erosion.

9. The method for preparing the seawater erosion resistant foamed concrete with ultrafine closed-cell structure according to claim 8, characterized in that: The density of the foam is 25-30 g / L; The water-cement ratio of the slurry is 0.45-0.

65.

10. Use of the ultrafine closed-cell structure seawater erosion-resistant foamed concrete according to any one of claims 1 to 7 in road construction in coastal areas.

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