Self-healing material for concrete cracks of compressed air energy storage artificial chamber and chemical self-healing method

Abstract

The invention belongs to the technical field of compressed air energy storage artificial chamber construction and design, and discloses a compressed air energy storage artificial chamber concrete crack self-healing material and a chemical self-healing method.The self-healing material comprises trigger gas with the volume ratio being 2%-5%, and the trigger gas is supercritical carbon dioxide or carbonyl sulfide; and the reactive curing agent is nanoscale calcium carbonate or calcium carbamate. The chemical self-healing method comprises the following steps: concrete generates cracks due to stress or temperature change, high-pressure gas containing trigger gas permeates along the cracks and reacts with curing components in the concrete to generate a high-strength filling material, the cracks are sealed, and the impermeability and structural integrity of the concrete are recovered. The invention provides a synergistic system of adding trigger gas in compressed gas and pre-burying a reactive additive in concrete, and utilizes sudden pressure drop and gas permeation during high-pressure gas leakage to trigger a chemical reaction in the crack so as to realize self-healing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of compressed air energy storage underground cavern construction design, and particularly relates to a concrete crack self-healing material and a chemical self-healing method for a compressed air energy storage underground cavern. BACKGROUND

[0002] A compressed air energy storage system stores high-pressure gas (such as compressed air or inert gas) in an artificial cavern (underground cavern) to convert electrical energy into compressed air potential energy. The concrete lining of the cavern is subjected to high surrounding rock stress, cyclic loading and temperature changes for a long time, and is prone to cracking. Crack propagation can lead to high-pressure gas leakage, reducing energy storage efficiency, and even causing safety accidents. In the prior art, concrete self-repairing relies on built-in capsules or microorganisms, but there are problems such as uncontrollable triggering conditions (such as relying only on the hydration environment of the crack itself) and low repair efficiency (difficult to deal with high-pressure gas leakage scenarios). SUMMARY

[0003] To solve the above technical problems, the present application provides a concrete crack self-healing material and a chemical self-healing method for a compressed air energy storage underground cavern, and proposes a synergistic system of "adding a trigger gas in the compressed air + embedding a reactive additive in the concrete", which utilizes the pressure drop and gas permeation when high-pressure gas leaks to trigger a chemical reaction in the crack and achieve self-healing.

[0004] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0005] A concrete crack self-healing material for a compressed air energy storage underground cavern, comprising:

[0006] A trigger gas added to the compressed air system, the volume fraction of the trigger gas being 2% to 5%, which is supercritical carbon dioxide or carbonyl sulfur;

[0007] A reactive curing agent added to the concrete, the reactive curing agent being nano-sized calcium carbonate or calcium carbamate with a particle size of 50 to 200 nm.

[0008] Optionally, the compressed air system comprises an energy storage main gas and a trigger gas, wherein the volume fraction of the energy storage main gas is 95% to 98%.

[0009] Further, the energy storage main gas is compressed air.

[0010] A chemical self-healing method for the aforementioned concrete crack self-healing material for a compressed air energy storage underground cavern, comprising the following steps:

[0011] (1) Crack generation stage: cracks are generated in the concrete due to stress or temperature changes, and the compressed air energy storage high-pressure gas containing the trigger gas permeates along the cracks;

[0012] (2) Trigger stage: for cracks, if supercritical carbon dioxide is used in the pressurized gas, supercritical carbon dioxide is released due to the pressure reduction in the cracks , and dissolved in the water in the cracks to generate ;

[0013] react with the concrete additive nano calcium carbonate:

[0014] ;

[0015] The generated is soluble, but due to the narrowness of the cracks, the solution is supersaturated in concentration and re-precipitates nano crystals to fill the crack pores;

[0016] react with the concrete additive nano :

[0017] ;

[0018] This reaction directly generates nano crystals to fill the crack pores;

[0019] If carbonyl sulfur is used in the pressurized gas, due to the pressure reduction in the cracks, carbonyl sulfur will be released after leakage, and sulfur-containing gas will be generated after hydrolysis ;

[0020] react with the concrete additive nano :

[0021] ;

[0022] The generated is soluble, but due to the narrowness of the cracks, the solution is supersaturated in concentration and re-precipitates nano crystals to fill the crack pores;

[0023] react with the concrete additive nano :

[0024] ;

[0025] The generated is soluble, but due to the narrowness of the cracks, the solution is supersaturated in concentration and re-precipitates nano crystals to fill the crack pores;

[0026] (3) Repair completion stage: cracks are filled with nano crystals generated directly or nano crystals re-precipitated after the solution is supersaturated in concentration or nano Crystal filling, restoring the impermeability and structural integrity of concrete.

[0027] Preferably, the crack width is 10 μm to 2 mm.

[0028] A kind of concrete, raw material includes cement, aggregate, water, and water-cement ratio is 0.4-0.45.

[0029] Further, the concrete further includes water reducing agent, and the mixing amount is 0.8% to 1.2% of the total mass of cement, aggregate and water.

[0030] Preferably, the water reducing agent is polycarboxylate type water reducing agent.

[0031] Further, the concrete further includes the aforementioned reactive curing agent, and the addition amount is 1% to 2% of the total mass of cement, aggregate and water.

[0032] Optionally, the cement is P.O 42.5 cement, the aggregate includes gravel and sand, the particle size of gravel is 5-20 mm, and the sand fineness modulus is 2.3-3.0.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] (1) Active self-healing: using the inherent characteristics of high-pressure gas leakage to trigger repair without external intervention;

[0035] (2) Wide crack adaptability: nano-crystal fills the crack, and the repair width range is 10 μm to 2 mm.

[0036] (3) Performance compatibility: the additive does not affect the initial strength of concrete (28-day compressive strength ≥ 40 MPa), and the bonding strength after repair is > 1.5 MPa;

[0037] (4) Long-term stability: the reaction product of the trigger gas and the additive (such as ) has stable chemical properties, excellent waterproof performance and impermeability, and can ensure the long-term stability of concrete. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is the direct shear test curve of the concrete test piece repaired by the present application.

[0039] Figure 2 is the uniaxial compression test curve of the concrete test piece with and without additive of the present application, and the horizontal and vertical coordinates in the figure are the conventional strain symbols. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0041] Example 1

[0042] A self-healing material for concrete cracks in a compressed air energy storage artificial chamber, comprising:

[0043] (1) Trigger gas added to the compressor system

[0044] Base gas: Main gas for energy storage (e.g., compressed air, accounting for 95%~98% (volume fraction)); Trigger gas: Supercritical carbon dioxide (selected) ) or carbonyl sulfide (COS), accounting for 2%~5% (volume fraction). Selection criteria: It exists in a supercritical state under high pressure (≥7.4MPa) and can be uniformly dissolved in compressed gas; when it leaks into an atmospheric pressure crack, the pressure drops sharply to 0.1~1MPa. Rapid expansion and release Gas, and at the same time, partially dissolved moisture in the cracks to form (Weak acid). COS is a sulfur-containing gas that can be hydrolyzed to form COS upon leakage. (Acidic gas) reacts with alkaline components in concrete.

[0045] Source of water within the cracks: The artificial chamber is buried underground, allowing for groundwater infiltration. Simultaneously, the concrete is constantly in contact with air, which contains moisture. The alkaline component of the chemical reaction in this invention is a nanomaterial, requiring very little water for the reaction, and the reaction process is relatively slow. As long as water enters the cracks during this process, the reaction can continue.

[0046] (2) Special additives in concrete

[0047] The additive is a reactive curing agent: nano-sized calcium carbonate ( ) or calcium carbamate ( The particle size is 50~200nm. Function: To provide an alkaline environment to react with acidic substances that trigger gas release (such as...). , The reaction produces insoluble salts (such as...) precipitation).

[0048] Example 2

[0049] A type of concrete, the raw materials of which include cement, aggregate, and water, with a water-cement ratio of 0.4 to 0.45; wherein the cement is P.O42.5 cement, the aggregate includes crushed stone and sand, the crushed stone has a particle size of 5 to 20 mm, and the sand has a fineness modulus of 2.3 to 3.0.

[0050] The concrete further comprises a water reducing agent, and the water reducing agent is a polycarboxylic acid type water reducing agent, and the content of the water reducing agent is 0.8%-1.2% of the total mass of cement, aggregate and water.

[0051] The raw material of the concrete further comprises the reactive curing agent in Example 1, and the addition amount of the reactive curing agent is 1%-2% of the total mass of cement, aggregate and water.

[0052] Example 3

[0053] A concrete preparation process according to Example 2, comprising the following steps:

[0054] Step 1, pretreatment of the additive: ultrasonic dispersion of the nanoscale or for 30 min;

[0055] Step 2, mixing: dry mixing of cement, aggregate, water and water reducing agent for 1 min, and then wet mixing of the additive for 3-5 min to ensure uniform dispersion of the additive;

[0056] Step 3, pouring and curing: pouring of the concrete into a chamber lining according to a conventional concrete process, and standard curing for 28 days.

[0057] A method for chemical self-healing of cracks in compressed air energy storage artificial chambers, using the self-healing material according to Example 1 and the concrete prepared according to the concrete preparation process according to Example 3, comprising the following steps:

[0058] (1) crack generation stage: cracks (width of 10 μm-2 mm) are generated in the concrete due to stress or temperature changes, and high-pressure gas (containing trigger gas) used in compressed air energy storage penetrates along the cracks.

[0059] (2) trigger stage: for the cracks, if supercritical carbon dioxide (CO2) is used in the compressed air, , the pressure in the cracks is reduced (close to normal pressure) to release , dissolved in the water in the cracks to form (pH≈4-5).

[0060] reacts with the concrete additive (nanoscale ):

[0061]

[0062] The generated is soluble, but due to the narrowness of the cracks, the solution is supersaturated in concentration and the nanoscale crystals are re-precipitated to fill the crack pores.

[0063] reacts with the concrete additive (nanoscale )reaction:

[0064]

[0065] This reaction directly generates nanoparticles. Crystals fill cracks and pores.

[0066] If carbonyl sulfide (COS) is used in the compressed gas, the pressure inside the crack will decrease, and the carbonyl sulfide will leak out, releasing sulfur-containing gas, which can be hydrolyzed to form... (Acidic gas).

[0067] With concrete additives (nano) )reaction:

[0068]

[0069] generated Soluble, but due to the narrow cracks, nanoparticles re-precipitate after the solution becomes supersaturated. Crystals fill cracks and pores.

[0070] With concrete additives (nano) )reaction:

[0071]

[0072] generated Soluble, but due to the narrow cracks, nanoparticles re-precipitate after the solution becomes supersaturated. Crystals fill cracks and pores.

[0073] (3) Repair completion stage: The crack is repaired by directly generated nanotechnology. Nanoparticles re-precipitated after crystal or solution concentration becomes supersaturated Crystalline or nano-CaS crystal filling restores the impermeability and structural integrity of concrete.

[0074] Example 5

[0075] Figure 1 The direct shear test curve of the repaired concrete specimen is shown. C35 concrete was used in the test, and the concrete mix ratio was: cement: water: sand: aggregate = 1 : 0.45 : 1.85 : 2.95. The amount of nano-calcium carbonate added was 1.5% of the total mass of cement, aggregate and water, and the amount of polycarboxylate superplasticizer was 1.0% of the total mass of cement, aggregate and water.

[0076] Self-healing concrete was prepared according to the method in Example 3. Cylindrical standard specimens, 100 mm high and 50 mm in diameter, were made from the self-healing concrete and subjected to uniaxial compressive strength tests. Specimens that developed cracks during the test were exposed to air and treated with water mist. The self-healing reaction occurring in the cracks was observed. After the cracks were filled with calcium carbonate crystals, a direct shear test was performed on the specimen. The shear test curve showed that after the self-healing reaction, the concrete strength could recover to a normal level. Figure 1 As shown, the shear strength of C35 concrete can reach over 1.5 MPa.

[0077] Example 6

[0078] Figure 2 The graphs show the uniaxial compressive strength test curves of concrete specimens with and without additives. The one with additives corresponds to Example 5, while the one without additives (i.e., without nano-calcium carbonate) serves as a control. The preparation method is the same as in Example 3.

[0079] Two types of concrete, one with additives and one without, were used to prepare standard cylindrical specimens, each 100 mm high and 50 mm in diameter, for uniaxial compressive strength tests.

[0080] like Figure 2 As shown, after adding the self-healing additive, the uniaxial compressive strength and deformation modulus of the concrete specimens decreased slightly, but still met the strength grade requirements of the concrete.

[0081] In summary, this invention utilizes a dual control mechanism of "compressed gas medium triggering + pre-embedded reactive components within the concrete" to ensure that when high-pressure gas leaks, the triggering gas it carries penetrates the cracks and reacts with the curing components within the concrete to generate a high-strength filling material that seals the cracks. Key technical points:

[0082] (1) Trigger gas selection: It exists stably in compressed gas under high pressure, and releases active substances due to a sudden drop in pressure after leakage (or reaction with the crack environment);

[0083] (2) Concrete additive design: a solidified component that can react with the trigger gas is embedded in the concrete. It is stable under normal conditions and generates solid filler quickly after triggering.

[0084] The above description is merely a specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any transformations or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A compressed air energy storage artificial cavern concrete crack self-healing material, characterized in that, The application relates to a concrete with a crack self-healing function. The trigger gas added to the compressed gas system has a volume ratio of 2%-5% and is supercritical carbon dioxide or carbonyl sulfur; The reactive curing agent added to the concrete is nano calcium carbonate or calcium carbamate with a particle size of 50-200 nm.

2. The compressed gas energy storage artificial cavern concrete crack self-healing material according to claim 1, characterized in that, The compressed gas system comprises a main energy storage gas and a trigger gas, wherein the volume ratio of the main energy storage gas is 95%-98%.

3. The compressed gas energy storage artificial cavern concrete crack self-healing material according to claim 2, characterized in that, The main energy storage gas is compressed air.

4. A chemical self-healing method of the compressed energy storage artificial cavern concrete crack self-healing material according to any one of claims 1-3, characterized in that, The application further discloses a preparation method of the concrete. (1) crack generation stage: cracks are generated in the concrete due to stress or temperature change, and the compressed gas energy storage gas containing the trigger gas penetrates along the cracks; (2) Triggering stage: for the fracture, if supercritical carbon dioxide is used in the pressurizing, supercritical carbon dioxide is released due to the pressure reduction in the fracture , and dissolved in the water in the fracture to generate ; Reaction with concrete additive nanoscale calcium carbonate: ； generated soluble, but due to the narrowness of the cracks, the solution re-precipitates nanocrystals when supersaturated in concentration, filling the crack porosity; crystals, filling the crack porosity; Nanoparticles for concrete additives Reaction: ； The reaction directly generates nanometer crystal to fill crack pores; If carbonyl sulphur is used in the pressurised gas, then again due to the reduced pressure in the crack, the carbonyl sulphur, after leakage, releases sulphur containing gases which hydrolyse to form ; Nanoparticles for concrete additives Reaction: ； generated soluble, but due to the narrowness of the cracks, the solution re-precipitates nanocrystals crystals, filling the crack pores; Nanoparticles for concrete additives Reaction: ； generated soluble, but due to the narrowness of the cracks, the solution re-precipitates nanocrystals when supersaturated in concentration, filling the crack porosity; crystals, filling the crack porosity; (3) Repair completion stage: cracks are filled by nano crystals re-precipitated from the oversaturated solution or nano crystals or nano crystals that are directly generated, restoring the impermeability and structural integrity of the concrete.

5. The chemical self-healing method according to claim 4, characterized in that, The crack width is 10-2 mm.

6. A concrete, characterized by The raw materials of the concrete include cement, aggregate and water, and the water-cement ratio is 0.4-0.

45.

7. The concrete according to claim 6, characterized in that The concrete further comprises a water reducing agent, and the mixing amount of the water reducing agent is 0.8%-1.2% of the total mass of the cement, aggregate and water.

8. The concrete according to claim 7, characterized in that The water reducing agent is a polycarboxylic acid type water reducing agent.

9. The concrete according to claim 7, characterized in that The concrete further comprises the reactive curing agent in claim 1, and the adding amount of the reactive curing agent is 1%-2% of the total mass of the cement, aggregate and water.

10. The concrete of claim 6, wherein The cement is P.O 42.5 cement, the aggregate comprises gravel and sand, the particle size of the gravel is 5-20 mm, and the sand fineness modulus is 2.3-3.0.

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