High-performance marine concrete with intelligent self-repairing function and preparation method thereof

Abstract

The invention relates to high-performance marine concrete with an intelligent self-repairing function and a preparation method thereof, and belongs to the technical field of building materials. The high-performance marine concrete is prepared from the following raw materials in parts by weight: 300 to 400 parts of cement, 600 to 800 parts of sand, 1000 to 1200 parts of pebbles, 30 to 50 parts of fly ash, 20 to 40 parts of slag powder, 5 to 10 parts of chloride ion sensitive sustained-release capsules, 1 to 5 parts of a nano material, 0.5 to 1 part of a water reducing agent and 160 to 200 parts of water. The chloride ion sensitive sustained-release capsule is introduced, when the chloride ion concentration of the concrete exceeds a design threshold value, a reinforcing steel bar passivation film repairing agent is automatically released, a reinforcing steel bar passivation film is repaired, chloride ion transmission is effectively inhibited, the corrosion resistance of reinforcing steel bars is improved, meanwhile, nano materials and the like are added, and the mechanical property of the concrete is improved in cooperation with other components; therefore, the durability is improved, and the maintenance cost is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and relates to a high-performance marine concrete with intelligent self-repairing function and a preparation method thereof. Background Art

[0002] Marine engineering concrete is easily deteriorated and cracked due to factors such as chloride ion erosion and carbonation, and steel bars are corroded when exposed to corrosive environments such as salt spray and seawater for a long time. Traditional anti-corrosion measures such as surface coatings or preservatives have limitations and cannot effectively prevent internal damage of concrete for a long time. In addition, concrete cracks are prone to expand under external forces, further exacerbating the overall failure of the structure. To solve these problems, a technical method of preventing steel bar corrosion by adding corrosion inhibitors has been proposed in the prior art, but its application in the marine environment still faces challenges. The present invention proposes a high-performance marine concrete with intelligent self-repairing function under this background. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-performance marine concrete with intelligent self-repairing function and a preparation method thereof. The present invention introduces chloride ion-sensitive slow-release capsules, which automatically release a steel bar passivation film repair agent when the chloride ion concentration in the concrete exceeds 1.0 mol / L, repair the steel bar passivation film, effectively inhibit chloride ion transmission, improve the corrosion resistance of steel bars, and at the same time add nano materials, etc., to synergistically improve the mechanical properties of the concrete with other components, thereby improving its durability and greatly reducing the maintenance and repair costs.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A high-performance marine concrete with intelligent self-repairing function, the raw materials of the high-performance marine concrete are calculated by weight, and include 300-400 parts of cement, 600-800 parts of sand, 1000-1200 parts of gravel, 30-50 parts of fly ash, 20-40 parts of slag powder, 5-10 parts of chloride ion-sensitive slow-release capsules, 1-5 parts of nano materials, 0.5-1 part of water reducing agent and 160-200 parts of water.

[0006] Further, the chloride ion-sensitive slow-release capsule is coated with a steel bar passivation film repair agent.

[0007] Further, the chloride ion-sensitive slow-release capsule is prepared by successively immersing the steel bar passivation film repair agent in a coating liquid and a crosslinking liquid.

[0008] Further, the raw materials of the chloride ion-sensitive slow-release capsule are calculated by mass percentage, and include 50% of the steel bar passivation film repair agent, 35% of the coating liquid and 15% of the crosslinking liquid; the steel bar passivation film repair agent is sodium nitrite with a purity of not less than 98%.

[0009] Furthermore, the raw materials of the encapsulation liquid include, by mass percentage, 2% chitosan, 0.5% sodium alginate, 1.5% glycerol and 96% acetic acid solution with a concentration of 2%.

[0010] Furthermore, the cross-linking liquid is a calcium chloride solution with a mass fraction of 5.0%, and the calcium chloride solution is prepared by dissolving calcium chloride powder with a purity of 97% in water.

[0011] Furthermore, the nano material is one or more of nano silicon dioxide with a purity of 99.5%, nano aluminum oxide with a purity of 99.9%, nano calcium oxide with a purity of 98%, or nano titanium oxide with a purity of 99.8%.

[0012] Furthermore, it is characterized in that: the preparation method comprises the following steps:

[0013] (1) Cement, sand, gravel, fly ash and slag powder are mixed uniformly in proportion to form a basic dry material mixture;

[0014] (2) adding chloride ion sensitive sustained-release capsules and nanomaterials to the basic dry material mixture and stirring again;

[0015] (3) adding water and a water reducing agent and stirring thoroughly until the collapse of the concrete reaches 180-220 mm to obtain a mixture;

[0016] (4) The mixture is poured into a mold and vibrated at a frequency of 50-100 Hz to form the mixture. After forming, the mold is removed after curing at 20° C. and 65% relative humidity for 24 hours. After removing the mold, the mixture is cured at 20° C. and 95% relative humidity for 28 days to obtain high-performance marine engineering concrete with intelligent self-repairing function.

[0017] Beneficial effects of the present invention:

[0018] (1) The chloride ion sensitive sustained-release capsule of the present invention contains a steel bar passivation film repair agent inside and a chloride ion responsive coating layer outside. When the chloride ion concentration inside the concrete exceeds the design threshold value (1.0 mol / L), the coating layer on the surface of the chloride ion sensitive sustained-release capsule will be induced to expand and be destroyed, releasing the steel bar passivation film repair agent wrapped therein, thereby achieving the purpose of repairing the steel bar passivation film. In addition, the present invention also adds nanomaterials to improve the compactness of concrete, thereby inhibiting the transmission of chloride ions inside the concrete and improving the effect of the chloride ion sensitive sustained-release capsule.

[0019] (2) The nanomaterials introduced in the present invention can improve the anti-penetration ability and mechanical properties of concrete, thereby improving the corrosion resistance of concrete. In combination with other components, the prepared concrete exhibits excellent freeze-thaw resistance, crack expansion resistance and durability in the marine environment, greatly reducing the cost of repair and maintenance. Brief Description of the Drawings

[0020] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 Schematic diagram of the 28-day compressive strength of the marine concrete prepared in Examples 1-7;

[0022] Figure 2 Schematic diagram of the 28-day splitting tensile strength of the marine concrete prepared in Examples 1-7. Detailed Embodiments

[0023] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, detail the specific embodiments, structures, features, and effects according to the present invention.

[0024] The cement in all examples and comparative examples of the present invention was directly purchased from the market, and it was all 52.5 early-strength cement produced by Ninghai Qiangjiao Conch Cement Co., Ltd.; the slag powder was directly purchased from the market, and it was all S95 slag powder produced by Zhangjiagang Hengchang New Building Materials Co., Ltd.; the fly ash was directly purchased from the market, and it was all Class I fly ash produced by Ningbo Economic and Technological Development Zone Xincheng Building Materials Co., Ltd.; the gravel was directly purchased from the market, and it was all crushed stone produced by Zhejiang Communications Investment Mining Co., Ltd.; the water reducer was directly purchased from the market, and it was all polycarboxylic acid high-performance water reducer produced by Jiangsu Aolaitai New Materials Co., Ltd.; the sand was taken from the river sand of Dongting Lake, and the water was tap water; sodium nitrite, chitosan, sodium alginate, acetic acid solution with a concentration of 2%, calcium chloride, nano-silica, nano-aluminum oxide, nano-calcium oxide, and nano-titanium oxide were all directly purchased from the market, and they were all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0025] Example 1

[0026] A preparation method of a high-performance marine concrete with intelligent self-healing function, comprising the following steps:

[0027] (1) After weighing the raw materials according to Table 1, mix the cement, sand, gravel, fly ash, and slag powder evenly in proportion to form a basic dry material mixture;

[0028] Table 1 Raw material mix ratio of Example 1 (the unit of raw materials is kg / m 3 )

[0029]

[0030] (2) Add chloride ion-sensitive slow-release capsules and nano-silica to the basic dry material mixture, and stir evenly again;

[0031] (3) Add water and water reducer, and stir thoroughly until the slump of the concrete reaches 180 mm to obtain a mixture;

[0032] (4) Pour the mixture into a mold, vibrate and form it at a frequency of 50 Hz. After forming, cure it for 24 hours in an environment of 20 °C and 65% relative humidity, then remove the mold. After removing the mold, cure it for another 28 days in an environment of 20 °C and 95% relative humidity to obtain high-performance marine concrete with intelligent self-healing function.

[0033] Test the compressive strength and splitting tensile strength according to GB / T50081-2019, and test the chloride ion penetration coefficient according to the standard GB / T50082-2024. The high-performance marine concrete with intelligent self-healing function prepared in Example 1 has 28-day compressive strength, splitting tensile strength, and 28-day chloride ion penetration coefficient of 60 MPa, 4.5 MPa, and 3.5×10 -12 m 2 / s.

[0034] Example 2

[0035] A preparation method of high-performance marine concrete with intelligent self-healing function, comprising the following steps:

[0036] (1) After weighing the raw materials according to Table 2, mix cement, sand, gravel, fly ash and slag powder evenly in proportion to form a basic dry material mixture;

[0037] Table 2 Raw material mix ratio of Example 2 (the unit of raw materials is kg / m 3 )

[0038]

[0039] (2) Add chloride ion-sensitive slow-release capsules and nano-alumina to the basic dry material mixture, and stir evenly again;

[0040] (3) Add water and water reducer, and stir thoroughly until the slump of the concrete reaches 220 mm to obtain a mixture;

[0041] (4) Pour the mixture into a mold, vibrate and form it at a frequency of 75 Hz. After forming, cure it for 24 hours in an environment of 20 °C and 65% relative humidity, then remove the mold. After removing the mold, cure it for another 28 days in an environment of 20 °C and 95% relative humidity to obtain high-performance marine concrete with intelligent self-healing function.

[0042] The compressive strength and splitting tensile strength were tested according to GB / T50081-2019, and the chloride ion permeability coefficient was tested according to GB / T50082-2024. The high-performance marine engineering concrete with intelligent self-repairing function prepared in Example 2 was measured to have a 28-day compressive strength, splitting tensile strength, and 28-day chloride ion permeability coefficient of 65.0 MPa, 5.0 MPa, and 3.4×10 -12 m 2 / s.

[0043] Example 3

[0044] A method for preparing high-performance marine engineering concrete with intelligent self-repairing function comprises the following steps:

[0045] (1) After weighing the raw materials according to Table 3, cement, sand, gravel, fly ash and slag powder are mixed evenly according to the proportion to form a basic dry material mixture;

[0046] Table 3 Raw material proportions of Example 3 (raw material units are all kg / m 3 )

[0047]

[0048] (2) adding chloride ion sensitive sustained-release capsules and nano calcium oxide to the basic dry material mixture and stirring again;

[0049] (3) adding water and a water reducing agent and stirring thoroughly until the collapse of the concrete reaches 190 mm to obtain a mixture;

[0050] (4) The mixture is poured into a mold and vibrated at a frequency of 75 Hz to form the mixture. After forming, the mold is removed after curing at 20° C. and 65% relative humidity for 24 hours. After removing the mold, the mixture is cured at 20° C. and 95% relative humidity for 28 days to obtain high-performance marine engineering concrete with intelligent self-repairing function.

[0051] The compressive strength and splitting tensile strength were tested according to GB / T50081-2019, and the chloride ion permeability coefficient was tested according to GB / T50082-2024. The high-performance marine engineering concrete with intelligent self-repairing function prepared in Example 3 was measured to have a 28-day compressive strength, splitting tensile strength, and 28-day chloride ion permeability coefficient of 70 MPa, 5.5 MPa, and 3.3×10 -12 m 2 / s.

[0052] Example 4

[0053] A method for preparing high-performance marine engineering concrete with intelligent self-repairing function comprises the following steps:

[0054] (1) After weighing the raw materials according to Table 4, cement, sand, gravel, fly ash and slag powder are mixed evenly according to the proportion to form a basic dry material mixture;

[0055] Table 4 Example 4 Raw material proportion (raw material units are kg / m 3 )

[0056]

[0057] (2) adding chloride ion sensitive sustained-release capsules and nano titanium dioxide to the basic dry material mixture and stirring again;

[0058] (3) adding water and a water reducing agent and stirring thoroughly until the collapse of the concrete reaches 200 mm to obtain a mixture;

[0059] (4) The mixture is poured into a mold and vibrated at a frequency of 90 Hz to form the mixture. After forming, the mold is removed after curing at 20° C. and 65% relative humidity for 24 hours. After removing the mold, the mixture is cured at 20° C. and 95% relative humidity for 28 days to obtain high-performance marine engineering concrete with intelligent self-repairing function.

[0060] The compressive strength and splitting tensile strength were tested according to GB / T50081-2019, and the chloride ion permeability coefficient was tested according to GB / T50082-2024. The high-performance marine engineering concrete with intelligent self-repairing function prepared in Example 4 was measured to have a 28-day compressive strength, splitting tensile strength, and 28-day chloride ion permeability coefficient of 75 MPa, 6.0 MPa, and 3.2×10 -12 m 2 / s.

[0061] Example 5

[0062] A method for preparing high-performance marine engineering concrete with intelligent self-repairing function comprises the following steps:

[0063] (1) After weighing the raw materials according to Table 5, cement, sand, gravel, fly ash and slag powder are mixed evenly according to the proportion to form a basic dry material mixture;

[0064] Table 5 Raw material proportion of Example 5 (raw material units are kg / m 3 )

[0065]

[0066]

[0067] (2) adding chloride ion sensitive sustained-release capsules and nano calcium oxide to the basic dry material mixture and stirring again;

[0068] (3) Add water and water reducer, and stir thoroughly until the slump of the concrete reaches 210 mm to obtain a mixture;

[0069] (4) Pour the mixture into a mold, vibrate and form it at a frequency of 85 Hz. After forming, cure it in an environment of 20 °C and 65% relative humidity for 24 hours, then remove the mold. After removing the mold, cure it in an environment of 20 °C and 95% relative humidity for 28 days to obtain high-performance marine concrete with intelligent self-healing function.

[0070] According to GB / T50081-2019, test the compressive strength and splitting tensile strength, and according to the standard GB / T50082-2024, test the chloride ion penetration coefficient. It is measured that the 28-day compressive strength, splitting tensile strength, and 28-day chloride ion penetration coefficient of the high-performance marine concrete with intelligent self-healing function prepared in Example 5 are 80 MPa, 6.5 MPa, and 3.1×10 -12 m 2 / s.

[0071] Example 6

[0072] A preparation method of high-performance marine concrete with intelligent self-healing function comprises the following steps:

[0073] (1) After weighing the raw materials according to Table 6, mix cement, sand, gravel, fly ash, and slag powder evenly in proportion to form a basic dry material mixture;

[0074] Table 6 Raw material mix ratio of Example 6 (the unit of raw materials is kg / m 3 )

[0075]

[0076] (2) Add chloride ion-sensitive slow-release capsules, nano-calcium oxide, and nano-silica to the basic dry material mixture, and stir evenly again;

[0077] (3) Add water and water reducer, and stir thoroughly until the slump of the concrete reaches 180 mm to obtain a mixture;

[0078] (4) Pour the mixture into a mold, vibrate and form it at a frequency of 100 Hz. After forming, cure it in an environment of 20 °C and 65% relative humidity for 24 hours, then remove the mold. After removing the mold, cure it in an environment of 20 °C and 95% relative humidity for 28 days to obtain high-performance marine concrete with intelligent self-healing function.

[0079] The compressive strength and splitting tensile strength were tested according to GB / T50081-2019, and the chloride ion permeability coefficient was tested according to GB / T50082-2024. The high-performance marine engineering concrete with intelligent self-repairing function prepared in Example 6 had a 28-day compressive strength, splitting tensile strength, and a 28-day chloride ion permeability coefficient of 85 MPa, 7.0 MPa, and 2.8×10 -12 m 2 / s.

[0080] Example 7

[0081] A method for preparing high-performance marine engineering concrete with intelligent self-repairing function comprises the following steps:

[0082] (1) After weighing the raw materials according to Table 7, cement, sand, gravel, fly ash and slag powder are mixed evenly according to the proportion to form a basic dry material mixture;

[0083] Table 7 Example 7 Raw material ratio (raw material units are kg / m 3 )

[0084]

[0085] (2) adding chloride ion sensitive sustained-release capsules, nano silicon dioxide, nano aluminum oxide and nano calcium oxide to the basic dry material mixture and stirring again;

[0086] (3) adding water and a water reducing agent and stirring thoroughly until the collapse of the concrete reaches 220 mm to obtain a mixture;

[0087] (4) The mixture is poured into a mold and vibrated at a frequency of 50 Hz to form the mixture. After forming, the mold is removed after curing at 20° C. and 65% relative humidity for 24 hours. After removing the mold, the mixture is cured at 20° C. and 95% relative humidity for 28 days to obtain high-performance marine engineering concrete with intelligent self-repairing function.

[0088] The compressive strength and splitting tensile strength were tested according to GB / T50081-2019, and the chloride ion permeability coefficient was tested according to GB / T50082-2024. The high-performance marine engineering concrete with intelligent self-repairing function prepared in Example 7 had a 28-day compressive strength, splitting tensile strength, and a 28-day chloride ion permeability coefficient of 90 MPa, 7.3 MPa, and 2.8×10 -12 m 2 / s.

[0089] As can be seen from Examples 1-7, the high-performance marine concrete with intelligent self-repairing function prepared by the present invention has excellent mechanical properties. Its 28-day compressive strength can reach 60-90 MPa, and its flexural strength can reach 4.5-7.3 MPa. By adding chloride ion-sensitive slow-release capsules, the chloride ion penetration coefficient of the concrete is improved, which can effectively reduce the corrosion rate of the internal steel bars in the concrete.

[0090] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any indirect modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A high-performance marine concrete with intelligent self-healing function, characterized in that: The raw materials of the high-performance marine concrete include, by weight, 300-400 parts of cement, 600-800 parts of sand, 1000-1200 parts of gravel, 30-50 parts of fly ash, 20-40 parts of slag powder, 5-10 parts of chloride ion sensitive sustained-release capsules, 1-5 parts of nanomaterials, 0.5-1 parts of water reducer and 160-200 parts of water.

2. The high-performance marine concrete with an intelligent self-repair function according to claim 1, characterized in that: The chloride ion sensitive sustained-release capsule is coated with a steel bar passivation film repairing agent.

3. The high-performance marine concrete with intelligent self-healing function according to claim 2, wherein: The chloride ion sensitive sustained-release capsule is prepared by sequentially immersing a steel bar passivation film repairing agent into a wrapping liquid and a cross-linking liquid.

4. A high-performance marine concrete with intelligent self-repair function according to claim 2, characterized in that: The raw materials of the chloride ion sensitive sustained-release capsule include, by mass percentage, 50% of a steel bar passivation film repair agent, 35% of a wrapping liquid, and 15% of a cross-linking liquid; The steel bar passivation film repair agent is sodium nitrite with a purity of not less than 98%.

5. The high-performance marine concrete with intelligent self-repairing function according to claim 4, characterized in that: The raw materials of the encapsulation liquid include, by mass percentage, 2% chitosan, 0.5% sodium alginate, 1.5% glycerol and 96% acetic acid solution with a concentration of 2%.

6. The high-performance marine concrete with intelligent self-repair function according to claim 4, characterized in that: The cross-linking liquid is a calcium chloride solution with a mass fraction of 5.0%, and the calcium chloride solution is prepared by dissolving calcium chloride powder with a purity of 97% in water.

7. A high-performance marine concrete with intelligent self-repair function according to claim 1, characterized in that: The nano material is one or more of nano silicon dioxide with a purity of 99.5%, nano aluminum oxide with a purity of 99.9%, nano calcium oxide with a purity of 98%, or nano titanium oxide with a purity of 99.8%.

8. A preparation method of a high-performance marine concrete with intelligent self-repairing function as described in any one of claims 1-6, characterized in that: The preparation method comprises the following steps: (1) Cement, sand, gravel, fly ash and slag powder are mixed uniformly in proportion to form a basic dry material mixture; (2) adding chloride ion sensitive sustained-release capsules and nanomaterials to the basic dry material mixture and stirring again; (3) adding water and a water reducing agent and stirring thoroughly until the collapse of the concrete reaches 180-220 mm to obtain a mixture; (4) The mixture is poured into a mold and vibrated at a frequency of 50-100 Hz to form the mixture. After forming, the mold is removed after curing at 20° C. and 65% relative humidity for 24 hours. After removing the mold, the mixture is cured at 20° C. and 95% relative humidity for 28 days to obtain high-performance marine engineering concrete with intelligent self-repairing function.

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