KR102047384B1 - Autogenous Crack Healing Microcapsule, Method for Manufacturing the Microcapsule, And Concrete Composition Having the Microcapsule - Google Patents

Abstract

The present invention relates to a concrete self-healing microcapsule and a method of manufacturing the same, and a concrete composition comprising the microcapsules, when a large amount of calcium carbonate is generated by the urea decomposable microorganism when the crack occurs in the interior of the concrete According to the present invention, the self-healing concrete microcapsules according to the present invention are formed by co-culturing urea degradable microorganisms that decompose urea to produce carbonate (CO ₃ ^2- ) and urea nondegradable microorganisms that do not decompose urea. It may include a core comprising a spore and a shell surrounding the core.

Description

Concrete self-healing microcapsules using microorganisms and manufacturing method thereof, self-healing concrete composition comprising the microcapsules {Autogenous Crack Healing Microcapsule, Method for Manufacturing the Microcapsule, And Concrete Composition Having the Microcapsule}

The present invention relates to microcapsules capable of self-healing concrete cracks and concrete compositions comprising the same, and more particularly, by incorporating spores co-cultured with urea degradable microorganisms and urea non-degradable microorganisms. The present invention relates to a concrete self-healing microcapsule using microorganisms and a method for manufacturing the same, and a concrete composition including the microcapsules, which are made of a large amount of calcium carbonate generated by urea degradable microorganisms when concrete cracks occur.

Concrete used in infrastructure and many buildings has the advantages of high compressive strength and excellent durability and easy maintenance, but low tensile strength and cracking due to shrinkage.

In the case of cracks in concrete, various methods for repairing the structure have been researched and developed due to the possibility of structural deterioration due to corrosion of steel and progress of neutralization. 'Is actively being researched.

Regarding self-healing concrete, a technique of utilizing microorganisms is typically developed.

The technology that utilizes microorganisms is that microorganisms produce minerals in and out of their bodies, that is, biomineralization, in which inorganic components are compounded by biopolymers such as organic components such as proteins and polysaccharides. This is achieved by forming a structure with precise order.

In particular, techniques for forming self-healing concrete, including microorganisms that precipitate carbonates in cement, have been attracting attention, but there is a problem that it is difficult to maintain microbial activity in cement in a base (alkali) environment. Even if this is done, there is a problem that the healing of relatively large cracks is difficult to occur in a short time.

As an example of the prior art to partially compensate for this, there is a "concrete using a microbial capsule and a method of manufacturing the same" of Patent No. 10-1448068, which is added to the concrete structure that is prepared by the preparation of the microbial culture medium in capsules By doing so, there is an advantage in that the loss of microorganisms can be minimized in a state of being installed in the water after the manufacturing process and the manufacturing process.

However, the prior art uses only a fatty acid binder for the protection of microorganisms capable of purifying water, and even when the binder is applied to microorganisms that precipitate calcium carbonate, the binder is dissolved in water in an alkaline solution so that it is dissolved in the cement of the base environment. There is a problem that is difficult to maintain the activity of microorganisms.

In addition, in the "method of water-condensation of concrete surface using a microbial culture medium containing calcium acetate" of Patent No. 10-1240240, the calcium carbonate crystals are generated by microorganisms having a urea decomposition function, and voids present on the concrete surface. By filling with calcium carbonate crystals and coating the concrete surface with calcium carbonate produced by microorganisms, the concrete surface is sealed to improve the water tightness of the concrete surface.

However, in the prior art using urea-decomposable microorganisms, the cell surface of the microorganisms is supersaturated by precipitated calcium carbonate, which does not absorb the surrounding nutrients, and does not generate self-healing due to the formation of carbonate ions (CO ₃ ^2- ) through urea decomposition. There is a problem that performance is reduced.

Patent Registration No. 10-1448068 Patent Registration No. 10-1240240 Patent Registration No. 10-1550258 Patent Publication No. 10-2017-0037399

The present invention is to solve the conventional problem, an object of the present invention is made by mixing a urea (degradable microorganism) and a spore (coore-cultured urea non-degradable microorganisms), a large amount of calcium carbonate when cracking concrete The present invention provides a self-healing concrete microcapsules using microorganisms that can be produced to heal cracks, a method for producing the same, and a concrete composition including the microcapsules.

Concrete self-healing microcapsules according to the present invention for achieving the above object, urea decomposable microorganisms that decompose urea (urea) to produce carbonate (CO ₃ ^2- ) and urea non-degradable microorganisms that do not decompose urea It may include a core comprising a spore formed by coculture and a shell surrounding the core.

The urea degradable microorganism is Sporosrcina pasteurii, Pseudomonas putida, Bacillus pseudofirmus, Bacillus pasteurii, Bacillus pasteurii, Asrobacter It may include any one or more of Arthrobacter crystallopoietes.

In addition, the urea non-degradable microorganism may include any one or more of Bacillus thuringiensis, Bacillus cohnii, Bacillus subtilis.

The core is made by mixing oil, yeast, and a spore formed by co-culture of the urea degradable microorganism and the urea nondegradable microorganism.

The urea degradable microorganism and the urea non-degradable microorganism may be included in a ratio of 6: 4 to 8: 2 by weight.

Method for producing a concrete self-healing microcapsules of the present invention as described above may be made of the following steps.

(a) coculture with urea degradable microorganisms and urea nondegradable microorganisms

(b) mixing spores of the urea degradable microorganism and the urea non-degradable microorganism produced in step (a) with oil;

(c) mixing the solution formed in step (b) with a surfactant

(d) incorporating and stirring the shell forming material into the mixed solution of the surfactant

(e) stabilizing by mixing the curing agent.

The step (a) is a step of preparing a medium in which TSB (Tryptic Soy Broth) and urea (urea) is mixed, urea (urea) degradable microorganisms and urea non-degradable microorganisms are added to the medium and cultured, Removing the supernatant after centrifuging the liquid, and lyophilizing the precipitated urea degradable microorganism and the urea non-degradable microorganism and then powdering to generate spores.

In the step (b), yeast is mixed with oil and mixed.

In the step (d), formaldehyde and melamine are sequentially added as a shell forming material, and stirred at a constant rotational speed in a temperature environment of 80 to 100 ° C.

In another aspect, the present invention provides a self-healing concrete composition comprising the microcapsules cement and aggregate, urea, calcium lactate (Calcium Lactate).

According to the present invention, since the spores co-cultured with urea degradable microorganisms and urea non-degradable microorganisms are incorporated into microcapsules and protected by a shell, the microorganisms can be maintained in concrete in a base (alkali) environment, and the hardening of concrete It is possible to prevent the phenomenon that the amount of microorganisms expressed by the pressure due to the time hydrate generation is reduced.

In addition, urea-degradable microorganisms and urea non-degradable microorganisms are mixed together at a predetermined ratio, so that carbonate ions (CO ₃ ^2- ) and calcium ions (Ca ²⁺ ) decomposed by urea-degradable microorganisms are combined. It can provide a nucleation site that can increase the amount of precipitation of calcium carbonate (CaCO ₃ ). Therefore, there is an effect that the self-healing performance is significantly improved when the crack of concrete occurs.

1 is a view showing the configuration of a self-healing concrete microcapsules according to an embodiment of the present invention.
Figure 2a is a schematic diagram illustrating the urea decomposition action by the urea degrading microorganisms incorporated into the microcapsules of the present invention.
Figure 2b is a schematic diagram illustrating the self-healing action by the urea degradable microorganisms and urea non-degradable microorganisms incorporated into the microcapsules of the present invention.
Figure 3 is a graph showing the experimental results of measuring the residual amount of calcium ions (Ca ²⁺ ) according to the mixing ratio of the urea degrading microorganisms and urea non-degradable microorganisms.
Figure 4 is a graph showing the experimental results of measuring the amount of calcium carbonate (CaCO ₃ ) according to the mixing ratio of the urea degradable microorganisms and urea non-degradable microorganisms.

Configurations shown in the embodiments and drawings described herein are only exemplary embodiments of the disclosed invention, there may be various modifications that can replace the embodiments and drawings of the present specification at the time of filing of the present application.

Hereinafter, with reference to the accompanying drawings, a concrete self-healing microcapsules, a manufacturing method thereof, and a self-healing concrete composition including the microcapsules will be described in detail according to embodiments described below. Like reference numerals in the drawings denote like elements.

Referring to Figure 1, the self-healing concrete microcapsules according to an embodiment of the present invention is to be self-healing action by automatically generating calcium carbonate when the cracks of the concrete is mixed in the concrete, the urea decomposing microorganism 11 and A core 10 formed by mixing a spore formed by co-culturing the urea non-degradable microorganism 12 with the oil 13 and the yeast 14, and a shell 20 surrounding the core 10. do.

The shell 20 is a polymer film having a thickness of approximately 0.01 ~ 30㎛, melamine-formaldehyde polymer, urea-formaldehyde polymer, polyurethane, urea-melamine-formaldehyde polymer, silica, polyurea resin, polyamide Resin, alginic acid, gelatin, gum arabic, acrylic acid resin, polymethyl methacrylate resin, polyvinyl alcohol resin, cellulose and the like. Such shell 20 may be made by known in situ methods, interfacial methods, coacervation methods, meltable dispersion methods, and other physical methods. The shell 20 preferably has appropriate mechanical properties that are not easily broken during handling and can be easily broken when cracking occurs.

The total size (diameter) of the microcapsules has a size of about 1 to 700 µm. In the microcapsules of the present invention, the urea degradable microorganism 11 present in the core 10 ruptures due to the cracking of concrete to generate carbonate ions (CO ₃ ^2- ), and the carbonate ions in the concrete are calcium ions (Ca ^2+). ) To heal calcium by producing calcium carbonate. At this time, the urea non-degradable microorganism 12 present in the core 10 does not act to generate carbonate ions (CO ₃ ^2- ), but provides a nucleation site for producing calcium carbonate, thereby reducing the amount of precipitation of calcium carbonate. It will act to increase.

Urea decomposable microorganism 11 decomposes urea in concrete to produce carbonate (CO ₃ ^2- ), and carbonate (CO ₃ ^2- ) reacts with calcium ions (Ca ²⁺ ) in concrete to By filling the main component of calcium carbonate (CaCO ₃ ), ie calcite or limestone, the cracks in concrete are filled. Urea degradable microorganisms include Sporosrcina pasteurii, Pseudomonas putida, Bacillus pseudofirmus, Bacillus pasteurii, and Asrobacter crystals. Ropoietes (Arthrobacter crystallopoietes), Bacillus spherericus (Bacillus sphaericus) may include any one or more.

The urea non-degradable microorganism 12 provides a nucleation site to which the carbonate (CO ₃ ^2- ) and calcium ions (Ca ²⁺ ) decomposed by the urea decomposable microorganism 11 can bind to calcium carbonate (CaCO). ₃ ) It increases the amount of precipitation. As described above, self-healing substances using conventional microorganisms contain only urea-decomposable microorganisms, in which case the cell surface of the urea-decomposable microorganisms is supersaturated by precipitated calcium carbonate and thus cannot absorb surrounding nutrients. Accordingly, the production of carbonate ions (CO ₃ ^2- ) through the decomposition of urea is not possible to reduce the amount of precipitated calcium carbonate (see FIGS. 2A and 2B).

In the microcapsules of the present invention, since the urea non-degradable microorganism 12 is mixed with the urea degradable microorganism 11, the urea non-degradable microorganism 12 is a carbonate (CO ₃ ^2- ) and calcium ion (Ca ²⁺ ). It is possible to increase the amount of precipitated calcium carbonate (CaCO ₃ ) by providing a nucleation site capable of binding.

The urea non-degradable microorganism 12 has a fast growth rate, and microorganisms capable of forming endospores may be applied. For example, the urea non-degradable microorganism 12 may include Bacillus thuringiensis and Bacillus cony ( Bacillus cohnii), Bacillus subtilis (Bacillus subtilis) may include any one or more.

The urea degradable microorganism 11 and the urea nondegradable microorganism 12 are preferably included in a ratio of 6: 4 to 8: 2 by weight. If the urea decomposing microorganism 11 is decomposing urea (urea), so creating a carbonate ion (CO ₃ ^2-) urea decomposing microorganisms (11) to contain less than urea non-degradable micro-organisms (12) Carbonate ions (CO ₃ ^2- ) Production amount is significantly reduced, rather the amount of precipitated calcium carbonate is significantly reduced than when only the urea-degradable microorganism 11 is present alone. On the contrary, if the amount of the urea non-degradable microorganism 12 is too small, the nucleation site is insufficient and the amount of precipitation of calcium carbonate is reduced. Therefore, in order to secure sufficient calcium carbonate precipitation amount, it is preferable that the urea non-degradable microorganism 12 is incorporated at 20 to 40% by weight of the total weight of the microorganisms.

The microcapsules of the present invention having a concrete self-healing function are manufactured by the following method.

(a) coculture with urea degradable microorganisms and urea nondegradable microorganisms

(b) mixing spores of the urea degradable microorganism and the urea non-degradable microorganism produced in step (a) with oil;

(c) mixing the solution formed in step (b) with a surfactant

(d) incorporating and stirring the shell forming material into the mixed solution of the surfactant

(e) stabilizing by mixing the curing agent

First, a medium for culturing microorganisms is prepared. For example, microbial culture medium is prepared by incorporating Tryptic Soy Broth (TSB) and urea (urea) in a predetermined ratio. Then urea-degradable microorganisms and urea non-degradable microorganisms are added to the prepared medium and cultured. Subsequently, the cultured liquid is centrifuged, the supernatant is removed, and the precipitated urea degradable microorganism and the urea non-degradable microorganism are lyophilized and powdered to generate spores (step a).

The spores of the urea degradable microorganism and the urea non-degradable microorganism thus prepared are mixed with the yeast together with the oil (step b), and then the resulting solution is stirred with the surfactant (step c).

As the oil, it is preferable to use a silicone oil having low reactivity with yeast which is a food for microorganisms, and examples thereof include cyclotetradimethylsiloxane, cyclopentadimethylsiloxane, cyclic polydimethylsiloxane, cyclodimethicones and polydimethyl. Siloxane, polyphenyltrimethylsiloxane, trimethylsilyl monopentaerythritol, fluorinated silicone, silicone gum, polydimethylsiloxane with a degree of polymerization of 2000 or more, silicone wax, alkylpolysiloxane, mercapto silicone copolymer, silicone resin (trimethylsiloxysilicate or the like) Instead of silicone oil, sweet almond oil, avocado oil, castor oil, olive oil, jojoba oil, sunflower oil, Coconut oil, corn oil, palm oil, apricot-kernel oil Vegetable or animal oils such as, mineral oils such as liquid paraffin may be used.

The proportion of oil is preferably in the range of 70 to 90% by weight, based on the total weight of the microcapsules.

Surfactants include alkyl sulphates, alkyl ether sulphates, alkaryl sulphonates, alkanoyl isethionates, alkyl succinates, alkyl sulfur succinates. Alkyl sulphosuccinates, N-alkoylsacrcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboylates, alpha-olefin sulfates alpha-olefin sulphonates) and the like can be used.

Subsequently, formaldehyde and melamine are sequentially added to the solution mixed with the surfactant as a shell forming material, and stirred at a rotational speed of 350 rpm or more for 2 hours or more in a temperature environment of 80 to 100 ° C.

In addition, the microcapsules are prepared by incorporating a curing agent to stabilize the formed solids and performing a stabilization process for a predetermined time (for example, 6 hours). As the curing agent, pyridine hydrochloride, diammonium phosphate and the like can be used.

When the microcapsules prepared in this way are mixed with cement, aggregate, urea, and calcium lactate, to prepare a concrete composition, when the crack occurs in concrete, the microcapsule at the crack is ruptured by the urea degradable microorganism. Carbonate ions are generated to precipitate calcium carbonate.

Urea and calcium lactate contained in the concrete composition are provided for the production of carbonate (CO ₃ ^2- ) and calcium ions (Ca ²⁺ ) by the urea degradable microorganisms.

In the concrete composition, the mixing ratio of aggregate and cement is preferably 1.5: 1 by weight, urea and calcium lactate are 1 to 5% by weight of cement, and microcapsules are preferably 0.5 to 3% by weight of cement. Do.

Example

Bacillus Turingensis (Sporosarcina pasteurii) and urea non-degradable microorganisms as urea-degradable microorganisms in microbial culture medium containing 30 g / L of Tryptic Soy Broth (TSB) and 20 g / L of urea (urea) Bacillus thuringiensis) were mixed in the ratios (weight ratios) of 10: 0, 9: 1, 8: 2, 7: 3, 6: 4, and 5: 5, respectively, to prepare a spore sample, and then the respective spore samples were urea and The culture was added to a medium containing calcium lactate and cultured to measure the residual amount of calcium ions (Ca ²⁺ ) and the amount of precipitated calcium carbonate (CaCO ₃ ).

The comparative example is a case where the compounding ratio of the urea-degradable microorganism and the urea non-degradable microorganism is 10: 0, that is, using a spore without adding the urea non-degradable microorganism at all, and Examples 1 to 5 are the urea-degradable microorganism and the urea non-degradable, respectively. The case where the spore which set the compounding ratio of microorganisms to 9: 1, 8: 2, 7: 3, 6: 4, 5: 5 is used.

First, referring to FIG. 3, the comparative examples and Examples 1 and 5 were found to have a large amount of calcium ions remaining over time as compared with Examples 2 to 4. That is, it can be seen that Examples 2 to 4 consume more calcium ions than Comparative Examples and Examples 1 and 5.

In addition, as shown in Figure 4 it can be seen that the amount of precipitation of calcium carbonate is also significantly more than Examples 2 to 4 and Comparative Examples and Examples 1 and 5.

In the case of Example 1, although the urea non-degradable microorganisms are incorporated, the absolute amount is not so low that it does not provide enough nucleation sites for the production of calcium carbonate (CaCO ₃ ), and thus does not have a significantly improved ability to produce calcium carbonate compared to the comparative example. Is analyzed.

In addition, the fifth embodiment of the case is small the absolute quantity of the urea-decomposing microorganisms that produce the carbonate ion (CO ₃ ^2-) to have a low ability to produce a small amount of calcium carbonate itself rather than the comparative examples of the carbonate ion (CO ₃ ^2-) Is analyzed.

The experimental results indicate that the consumption of calcium ions (Ca ²⁺ ) and the precipitation of calcium carbonate (CaCO ₃ ) are the highest when urea-degradable microorganisms and urea non-degradable microorganisms are mixed at a ratio of 8: 2 (Example 2). It can be seen that, the ratio of urea degradable microorganisms and urea non-degradable microorganisms advantageous for self-healing is found to be 6: 4 ~ 8: 2.

Although the present invention has been described in detail with reference to the embodiments, those skilled in the art to which the present invention pertains will be capable of various substitutions, additions, and modifications without departing from the technical spirit described above. It is to be understood that such modified embodiments are also within the protection scope of the present invention as defined by the appended claims.

10: core 11: urea degradable microorganism
12 urea non-degradable microorganism 13 oil
14: East 20: Shell

Claims (10)

A core comprising a spore formed by co-culturing a urea degradable microorganism that decomposes urea to produce a carbonate (CO ₃ ^2- ) and a urea non-degradable microorganism that does not decompose urea, and surrounds the core. Contains the shell,
The urea (degradable microorganism) and urea non-degradable microorganisms are concrete self-healing microcapsules are included in the ratio of 6: 4 to 8: 2 by weight. The method of claim 1,
The urea degradable microorganism,
Sporosrcina pasteurii, Pseudomonas putida, Bacillus pseudofirmus, Bacillus pasteurii, Arthrobacter crystallopoietes Concrete self-healing microcapsules containing any one or more of. The method of claim 1,
The urea non-degradable microorganism,
Concrete self-healing microcapsules comprising any one or more of Bacillus thuringiensis, Bacillus cohnii, Bacillus subtilis. The method of claim 1,
The core is a concrete self-healing microcapsule made by mixing oil, yeast, and a spore formed by co-culturing the urea degradable microorganism and the urea non-degradable microorganism. delete As a method of manufacturing concrete self-healing microcapsules,
(a) coculture with urea degradable microorganisms and urea nondegradable microorganisms;
(b) mixing a spore of the urea degradable microorganism and the urea non-degradable microorganism produced in step (a) with an oil;
(c) mixing the solution formed in step (b) with a surfactant;
(d) incorporating and stirring the shell forming material into the solution in which the surfactant is mixed;
(e) mixing and stabilizing the curing agent;
Including,
The step (a) is a step of preparing a medium containing TSB (Tryptic Soy Broth) and urea (urea), urea (urea) degrading microorganisms and urea non-degradable microorganisms in the culture medium, the step of culturing Removing the supernatant after centrifuging the liquid, and lyophilizing the precipitated urea degradable microorganisms and the urea non-degradable microorganisms, followed by powdering to produce spores. delete The method of claim 6, wherein in the step (b), yeast is mixed with oil and mixed. The method of claim 6, wherein in the step (d), formaldehyde and melamine are sequentially added as a shell forming material and stirred at a constant rotational speed in a temperature environment of 80 to 100 ° C. Self-healing concrete composition comprising the microcapsules according to any one of claims 1 to 4, including cement, aggregate, urea, calcium lactate.

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