Marine corrosion-resistant concrete and its preparation method and use

Abstract

The application provides a marine corrosion-resistant concrete and a preparation method and application thereof. The marine corrosion-resistant concrete comprises the following raw material components in parts by weight: cementitious material 60-120 parts, auxiliary cementitious material 60-120 parts, coarse aggregate 240-960 parts, fine aggregate 120-480 parts, water reducing agent 1-4 parts, corrosion-resistant additive 4-12 parts, and water 30-72 parts. The marine corrosion-resistant concrete has good rapid setting, rapid hardening and corrosion-resistant performance, and is suitable for marine engineering.

Description

Technical Field

[0001] This invention relates to the field of building materials, and in particular to a marine corrosion-resistant concrete, its preparation method, and its applications. Background Technology

[0002] In marine environments, concrete faces extremely harsh corrosive conditions. Seawater, as the primary corrosive solution, has a complex ionic composition, including chloride, sulfate, magnesium, potassium, and sodium ions. Chloride and sulfate ions are the main corrosive ions, which can corrode the steel reinforcement inside the concrete, posing a serious threat to the safe use and durability of the entire engineering structure.

[0003] Currently, marine concrete technology primarily mitigates corrosion caused by the marine environment through two methods. The first involves using admixtures such as water-reducing agents, expanding agents, and corrosion inhibitors to regulate the consistency and density of the concrete, thereby improving the cohesiveness and density of the paste and maintaining good resistance to harmful ions such as chloride ions. The second method involves incorporating various auxiliary cementitious materials such as fly ash or slag powder, which effectively reduces the porosity of the concrete, thus significantly lowering the chloride ion content and apparent chloride ion diffusion coefficient.

[0004] Given that silicate cement is still the most widely used cement matrix in marine engineering, its long setting time, low early strength, and poor erosion resistance make it difficult to meet the needs of marine engineering projects. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a marine corrosion-resistant concrete, its preparation method and uses, to solve the problems in the prior art.

[0006] To achieve the above and other related objectives, the present invention is obtained by including the following technical solutions.

[0007] This invention provides a marine corrosion-resistant concrete, comprising the following raw material components in parts by weight:

[0008]

[0009] Preferably, the cementing material is one or more selected from sulfoaluminate cement, silicate cement and anhydrous gypsum.

[0010] More preferably, the cementing material is a mixture of sulfoaluminate cement, silicate cement and anhydrous gypsum, wherein, based on the total mass of the cementing material, the content of sulfoaluminate cement is not less than 30 wt%, and the content of anhydrous gypsum is 10 to 40 wt%.

[0011] More preferably, the sulfoaluminate cement is a high-belite sulfoaluminate cement with a belite content of not less than 45%.

[0012] More preferably, the silicate cement is P·O42.5.

[0013] More preferably, the anhydrous calcium sulfate content in the anhydrous gypsum is not less than 80%.

[0014] Preferably, the auxiliary cementing material is one or more selected from slag, fly ash, steel slag powder, and limestone powder.

[0015] More preferably, the slag is S95 grade slag powder.

[0016] More preferably, the specific surface area of ​​the slag is 400-450 m². 2 / kg, with an activity index of over 98% after 28 days.

[0017] More preferably, the fly ash is Class I fly ash.

[0018] More preferably, the specific surface area of ​​the fly ash is 450-500 m². 2 / kg.

[0019] More preferably, the specific surface area of ​​the steel slag powder is 430-500 m². 2 / kg, and the calcium oxide content is not less than 35%.

[0020] More preferably, the limestone powder has a particle size range of 0.18–90 μm and a 28-day activity index of not less than 70%.

[0021] Preferably, the coarse aggregate has a particle size of 5–20 mm.

[0022] Preferably, the coarse aggregate is crushed stone.

[0023] More preferably, the coarse aggregate includes two gradations: 5-10 mm and 10-20 mm. The 5-10 mm gradation of the coarse aggregate accounts for 40-50 wt% of the total mass of the coarse aggregate.

[0024] Preferably, the fine aggregate is selected from one or both of quartz sand and iron tailings sand. More preferably, the fine aggregate is selected from a mixture of quartz sand and iron tailings sand, and the mass ratio of quartz sand to iron tailings sand is (2-5):1.

[0025] More preferably, the quartz sand has a particle size range of 0.12 to 0.38 mm and contains two gradations: 0.12 to 0.18 mm and 0.18 to 0.38 mm, wherein the mass ratio of the 0.12 to 0.18 mm gradation to the 0.18 to 0.38 mm gradation is 1:(1 to 5).

[0026] More preferably, the iron tailings sand has a particle size range of 0.15 to 0.315 mm and a fineness modulus of 1.2 to 1.5.

[0027] Preferably, the water-reducing agent is selected from polycarboxylate-based water-reducing agents. The water-reducing agent has a water reduction rate greater than 30%.

[0028] Preferably, the corrosion-resistant additive comprises the following raw material components in parts by weight:

[0029]

[0030] Preferably, the average particle size of the organosilicon hydrophobic powder is 110-130 μm, and the bulk density is 280-320 g / L.

[0031] Preferably, the specific surface area of ​​the calcium sulfoaluminate expanding agent is ≥2000 cm². 2 / g.

[0032] Preferably, the highly active silica contains more than 99.8 wt% silica, has an average particle size of 18–22 nm, and a specific surface area of ​​240–260 m². 2 / g.

[0033] The present invention also discloses a method for preparing marine corrosion-resistant concrete as described above, wherein the raw material components are mixed evenly.

[0034] The present invention also discloses the use of the marine corrosion-resistant concrete described above in cross-sea bridge structures or coastal wharves.

[0035] Compared with existing marine engineering concrete materials, the advantages of this invention are as follows:

[0036] 1. This invention uses a ternary composite material of sulfoaluminate cement-silicate cement-gypsum to replace traditional silicate cement. The ternary composite material has good rapid setting, rapid hardening and corrosion resistance, and is suitable for marine engineering.

[0037] 2. This invention uses a formulated anti-corrosion admixture to effectively ensure the concrete's resistance to chloride ion erosion and improve the durability of marine engineering projects.

[0038] 3. This invention uses a large amount of solid waste, which is in line with the policies of sustainable development, energy conservation and low carbon emissions, and effectively achieves green energy conservation and efficient recycling of resources. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0040] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0041] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0042] In this embodiment of the application, a more specific marine corrosion-resistant concrete is provided, which comprises the following raw material components in parts by weight: 60-120 parts of cementitious material, 60-120 parts of auxiliary cementitious material, 240-960 parts of coarse aggregate, 120-480 parts of fine aggregate, 1-4 parts of water-reducing agent, 4-12 parts of corrosion-resistant admixture, and 30-72 parts of water.

[0043] Specifically, the cementitious material comprises 60 parts, auxiliary cementitious material 60-90 parts, coarse aggregate 240-300 parts, fine aggregate 120-180 parts, water-reducing agent 1-2 parts, corrosion-resistant admixture 4-8 parts, and water 36-54 parts.

[0044] The auxiliary cementitious material can be 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, or 90 parts.

[0045] The coarse aggregate may be 240 parts, 245 parts, 250 parts, 255 parts, 260 parts, 265 parts, 270 parts, 275 parts, 280 parts, 285 parts, 290 parts, 295 parts, or 300 parts.

[0046] The fine aggregate can be 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, 160 parts, 165 parts, 170 parts, 175 parts or 180 parts.

[0047] The specific specifications of the raw material components used are as follows:

[0048] The cementitious material is a mixture of sulfoaluminate cement, silicate cement, and anhydrous gypsum, wherein, based on the total mass of the cementitious material, the content of sulfoaluminate cement is not less than 30 wt%, and the content of anhydrous gypsum is 10 wt% to 40 wt%. More preferably, the content of anhydrous gypsum is 15 wt% to 35 wt%, such as 15 wt%, 20 wt%, 25 wt%, 30 wt%, or 35 wt%. More preferably, the content of sulfoaluminate cement is 30 wt% to 50 wt%, such as 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0049] The sulfoaluminate cement is a high-belite sulfoaluminate cement with a belite content of not less than 45%.

[0050] The silicate cement is P·O42.5.

[0051] The anhydrous calcium sulfate content in the anhydrous gypsum is not less than 80%.

[0052] The auxiliary cementing material is selected from one or more of slag, fly ash, steel slag powder, and limestone powder.

[0053] Preferably, based on the total mass of the auxiliary cementitious materials, the slag content is at least 20 wt%, and the limestone powder content is no more than 35 wt%. More specifically, based on the total mass of the auxiliary cementitious materials, the slag content is 20-35 wt%, the fly ash content is 15-35 wt%, and the steel slag powder content is 20-35 wt%.

[0054] The slag is S95 grade slag powder, and the specific surface area of ​​the slag is 400-450 m². 2 / kg, with an activity index of over 98% after 28 days. The fly ash is Class I fly ash, with a specific surface area of ​​450–500 m². 2 / kg. The specific surface area of ​​the steel slag powder is 430-500 m². 2 / kg, and the calcium oxide content is not less than 35%. The limestone powder has a particle size range of 0.18 to 90 μm and a 28-day activity index of not less than 70%.

[0055] The coarse aggregate is crushed stone with a particle size of 5-20 mm. The coarse aggregate includes two gradations: 5-10 mm and 10-20 mm. The mass of the coarse aggregate with the 5-10 mm gradation accounts for 40-50 wt% of the total mass of the coarse aggregate.

[0056] The fine aggregate is selected from one or both of quartz sand and iron tailings sand. More specifically, the fine aggregate is selected from a mixture of quartz sand and iron tailings sand, and the mass ratio of the quartz sand to the iron tailings sand is (2-5):1. For example, it can be 2:1, 3:1, 4:1 or 5:1.

[0057] The particle size range of the quartz sand is 0.12 to 0.38 mm, and it contains two gradations: 0.12 to 0.18 mm and 0.18 to 0.38 mm. The mass ratio of the 0.12 to 0.18 mm gradation to the 0.18 to 0.38 mm gradation is 1:(1 to 5), such as 1:1, 1:2, 1:3, 1:4 or 1:5.

[0058] The iron tailings sand has a particle size range of 0.15 to 0.315 mm and a fineness modulus of 1.2 to 1.5.

[0059] The water-reducing agent is selected from polycarboxylate-based water-reducing agents. The water reduction rate of the water-reducing agent is greater than 30%.

[0060] More specifically, the corrosion-resistant additive may be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts.

[0061] Specifically, the corrosion-resistant additive comprises the following raw material components in parts by weight:

[0062]

[0063] The average particle size of the organosilicon hydrophobic powder is 110-130 μm, and the bulk density is 280-320 g / L.

[0064] The calcium sulfoaluminate expanding agent has a specific surface area ≥2000 cm². 2 / g.

[0065] The highly active silica contains more than 99.8 wt% silica, has an average particle size of 18–22 nm, and a specific surface area of ​​240–260 m². 2 / g.

[0066] Example 1

[0067] This embodiment provides a specific marine corrosion-resistant concrete and its preparation method.

[0068] It is composed of the following components by weight: 30 parts sulfoaluminate cement, 15 parts silicate cement, 15 parts gypsum, 20 parts slag, 20 parts fly ash, 20 parts steel slag powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, 4 parts corrosion-resistant admixture, and 36 parts water.

[0069] The corrosion-resistant additive contains 2.4 parts of highly active silica, 0.8 parts of sodium silicate, 0.4 parts of organosilicon hydrophobic powder, and 0.4 parts of calcium sulfoaluminate expander.

[0070] Example 2

[0071] This embodiment provides a marine corrosion-resistant concrete and its preparation method.

[0072] It is composed of the following components by weight: 30 parts sulfoaluminate cement, 20 parts silicate cement, 10 parts gypsum, 30 parts slag, 20 parts fly ash, 20 parts steel slag powder, 20 parts limestone powder, 300 parts crushed stone, 250 parts quartz sand, 50 parts iron tailings sand, 1 part water-reducing agent, 5 parts corrosion-resistant admixture, and 45 parts water.

[0073] The corrosion-resistant additive contains 3 parts of highly active silica, 1 part of sodium silicate, 0.5 parts of organosilicon hydrophobic powder, and 0.5 parts of calcium sulfoaluminate expander.

[0074] Example 3

[0075] This embodiment provides a marine corrosion-resistant concrete and its preparation method.

[0076] It is composed of the following components by weight: 20 parts sulfoaluminate cement, 20 parts silicate cement, 20 parts gypsum, 20 parts slag, 15 parts fly ash, 20 parts steel slag powder, 25 parts limestone powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, 5 parts corrosion-resistant admixture, and 45 parts water.

[0077] The corrosion-resistant additive contains 1.5 parts of highly active silica, 1 part of sodium silicate, 1 part of organosilicon hydrophobic powder, and 1.5 parts of calcium sulfoaluminate expander.

[0078] Example 4

[0079] This embodiment provides a marine corrosion-resistant concrete and its preparation method.

[0080] It is composed of the following components by weight: 20 parts sulfoaluminate cement; 30 parts silicate cement; 10 parts gypsum; 20 parts slag; 20 parts fly ash; 20 parts steel slag powder; 240 parts crushed stone; 120 parts quartz sand; 60 parts iron tailings sand; 2 parts water-reducing agent; 8 parts corrosion-resistant admixture; and 54 parts water.

[0081] The composition includes 2.4 parts of highly active silica, 1.6 parts of sodium silicate, 1.6 parts of organosilicon hydrophobic powder, and 2.4 parts of calcium sulfoaluminate expander.

[0082] Comparative Example 1

[0083] The concrete in Comparative Example 1 differs from the examples only in its gelling material, which is composed of the following components in parts by weight: 60 parts silicate cement, 20 parts slag, 20 parts fly ash, 20 parts steel slag powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, 4 parts corrosion-resistant admixture, and 36 parts water. The corrosion-resistant admixture contains 2.4 parts highly active silica, 0.8 parts sodium silicate, 0.4 parts organosilicon hydrophobic powder, and 0.4 parts calcium sulfoaluminate expansive agent.

[0084] Comparative Example 2

[0085] Compared with Example 1, the concrete in Comparative Example 2 was made without the corrosion-resistant admixtures described in this application, and consisted of the following components by weight: 30 parts sulfoaluminate cement, 15 parts silicate cement, 15 parts gypsum, 20 parts slag, 20 parts fly ash, 20 parts steel slag powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, and 36 parts water.

[0086] Comparative Example 3

[0087] Compared with Example 1, the concrete in Comparative Example 3 was only different in that it did not use sulfoaluminate cement. It was composed of the following components by weight: 40 parts silicate cement, 20 parts gypsum, 20 parts slag, 20 parts fly ash, 20 parts steel slag powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, 4 parts corrosion-resistant admixture, and 36 parts water.

[0088] The corrosion-resistant additive contains 2.4 parts of highly active silica, 0.8 parts of sodium silicate, 0.4 parts of organosilicon hydrophobic powder, and 0.4 parts of calcium sulfoaluminate expander.

[0089] Comparative Example 4

[0090] Compared with Example 1, the concrete in Comparative Example 4 differs only in the composition of the corrosion-resistant admixture, which consists of the following components by weight: 30 parts sulfoaluminate cement, 15 parts silicate cement, 15 parts gypsum, 20 parts slag, 20 parts fly ash, 20 parts steel slag powder, 240 parts crushed stone, 80 parts quartz sand, 40 parts iron tailings sand, 1 part water-reducing agent, 4 parts corrosion-resistant admixture, and 36 parts water.

[0091] The corrosion-resistant additive contains 2.4 parts of highly active silica and 1.6 parts of sodium silicate.

[0092] In the embodiments and comparative examples of this application, the compressive strength is tested using the following method:

[0093] Cementitious materials, auxiliary cementitious materials, coarse aggregate, fine aggregate, water-reducing agent, corrosion-resistant admixture, and water;

[0094] Add coarse and fine aggregates to a mixer and mix for 2 minutes. Then add cementitious materials and corrosion-resistant additives and mix for 1 minute.

[0095] Dissolve the water-reducing agent thoroughly in water, then add it to the mixer and stir for 2 minutes.

[0096] After mixing, the slurry was poured into a 100mm×100mm×100mm mold for compressive strength testing, and into a 100mm×50mm mold for electrical flux and chloride ion unsteady-state diffusion testing. Concrete specimens were placed in an environment of 20±5℃ for 24 hours according to the relevant provisions of GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" before demolding. After demolding, they were placed in a curing chamber at 20±2℃ and a relative humidity of over 95% for 28 days and 56 days.

[0097] The test method for the 56-day chloride ion diffusion coefficient refers to the rapid chloride ion migration coefficient method in GB / T50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete".

[0098] Table 1

[0099]

[0100]

[0101] As shown in Table 1, the mortar strength development in the examples was good, with 3-day strength between 34 and 43 MPa; 28-day strength between 56 and 64 MPa; and 56-day strength between 61 and 70 MPa. The chloride ion diffusion coefficient was 7.9 × 10⁻⁶ MPa. -12 ~13.6×10 - 12 m 2 s -1 .

[0102] Compared with the comparative examples, the marine corrosion-resistant concrete of the present invention exhibits rapid early-stage strength development, higher later-stage strength, and better resistance to chloride ion erosion. In particular, the comparison between the comparative examples and Example 1 highlights the unique advantages of the cementitious materials and corrosion-resistant admixtures of the present invention.

[0103] In summary, all embodiments exhibit good performance, and the present invention has good application value.

[0104] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A marine corrosion resistant concrete, characterized in that, The raw material components are composed of the following weight parts: The cementing material is a mixture selected from the group consisting of sulphoaluminate cement, Portland cement and anhydrous gypsum; the content of the sulphoaluminate cement is not less than 30wt% and the content of the anhydrous gypsum is 10-40wt% based on the total mass of the cementing material; The sulphoaluminate cement is high belite sulphoaluminate cement with a belite content of not less than 45%; The Portland cement is P·O42.5; The anhydrous calcium sulphate content in the anhydrous gypsum is not less than 80%; The corrosion-resistant admixture is composed of the following weight parts of raw material components: The high-activity silicon dioxide has a silicon dioxide content of greater than 99.8 wt%, an average particle size of 18-22 nm, and a specific surface area of 240-260 m 2 / g. The average particle size of the silicone hydrophobic powder is 110-130μm and the bulk density is 280-320g / L; The calcium sulphoaluminate expansive agent has a specific surface area of > 2000 cm 2 / g.

2. The marine corrosion resistant concrete according to claim 1, wherein The auxiliary cementing material is selected from one or more of the group consisting of slag, fly ash, steel slag powder and limestone powder.

3. The marine corrosion resistant concrete according to claim 1, wherein The coarse aggregate is crushed stone with a particle size of 5-20mm; And / or, the coarse aggregate includes two gradations of 5-10mm and 10-20mm.

4. The marine corrosion resistant concrete according to claim 1, wherein The fine aggregate is selected from one or both of the group consisting of quartz sand and iron tailings sand.

5. The marine corrosion resistant concrete according to claim 1, wherein The water reducing agent is selected from polycarboxylic acid type water reducing agent.

6. A method for preparing the marine corrosion-resistant concrete according to any one of claims 1-5 by mixing the raw material components uniformly.

7. Use of the marine corrosion-resistant concrete according to any one of claims 1-5 in a cross-sea bridge structure or a coastal wharf.

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