KR102585517B1 - Manufacturing and construction methods for crack self-healing materials to prevent leakage and faulty at the concrete joints of structures - Google Patents

Abstract

As a material for preventing leaks and defects in construction joints of structures, a method of manufacturing and constructing shotcrete, a joint repair material containing a crack self-healing ring, is disclosed, instead of using conventional organic water-stop plates, water-stop materials, waterproof plates, etc. The present invention relates to inorganic material-based ring aggregates, biomineral-forming bacteria-based ring aggregates, highly absorbent fiber-based crack healing ring aggregates, capsules containing one or more of these aggregates, or one or more of these aggregates. Self-healing ring aggregates coated with biodegradable membranes are used to mix joint repair materials to heal cracks through hydration reaction or biomineral formation when moisture flows into the cracks at the expansion joint area where the joint material containing the joint repair material is constructed. Provides a method.

Description

{Manufacturing and construction methods for crack self-healing materials to prevent leakage and faulty at the concrete joints of structures}

The present invention relates to a joint repair material for preventing defects (joint cracks) and water leaks occurring at construction joints of cast-in-place concrete structures or precast concrete structures.

In the case of concrete structures, including precast concrete structures, construction joints inevitably occur during new construction, especially considering the structural necessity during construction and the limits of form deformation due to concrete lateral pressure, etc., and water leakage occurs frequently in these areas. Occurs. Most of these cases are caused by cracks occurring at the joints of the structure. Due to the structure of the building, deformation due to concrete aging and ground pressure, such as load-bearing walls or underground sumps and sumps, where stress from the upper load is concentrated, is frequent. It often occurs on external walls. In addition, expansion and contraction of a certain length occurs due to phenomena such as temperature expansion and drying shrinkage of the concrete itself, and the stress generated by this expansion leads to larger cracks in the construction joints where structures are connected to each other. Accordingly, water leakage can frequently be observed in culverts, which are precast concrete structures that extend longitudinally.

As a preemptive treatment method to prevent water leakage due to structural cracks, a method of installing and constructing expansion materials such as water-expandable rubber water-stop material, bentonite water-stop material, and PCV water-stop material (water-stop plate) at construction joints is used. Water-expandable rubber water-stop material is an organic material and has a different coefficient of linear expansion from the concrete material, which is disadvantageous in its integral behavior with concrete when deformation of the structure occurs. In other words, this material lacks the ability to compensate for cracks caused by concrete deformation, and has the disadvantage of requiring preparation of the base surface, such as installing keyways, during construction. Bentonite water stopper is a product made by compressing and molding sodium bentonite with high expansion properties and packaging it with non-woven fabric. It has the effect of filling cracks due to the hydration and expansion of bentonite and prevents water leakage. However, the volume increase due to hydration expansion of bentonite reaches 16 times, which can lead to greater deformation at the expansion joint area, which leads to worsening of water leakage. In addition, bentonite water-stop material can hydrate and expand early under the influence of rainwater that penetrates into concrete before cracks occur, so it has the disadvantage of not being effective in blocking water leakage when cracks occur in places where moisture infiltration is frequent. PVC water-stop material is manufactured into various cross-sectional shapes by extrusion molding using soft vinyl chloride as the main raw material, and is used as a material to prevent water leakage at joints or expansion joints of concrete structures. The PVC water stopper installation method is known to be the most common method for preventing water leaks, but construction is relatively complicated due to the influence of rebar exposed at concrete expansion joints or connections, and as an expensive material, constructability and economic feasibility are poor. PVC water-stop material is also an organic material, so its adhesion is very low due to its material heterogeneity with concrete, and it is easily deformed or damaged by the concrete connected to and poured into expansion joints, which can reduce the effectiveness of blocking water leaks.

Paint waterproofing, plaster waterproofing, and sheet waterproofing are typically used as post-concept repair methods to solve water leaks due to structural cracks. These methods penetrate and apply waterproof materials to concrete walls, etc. to prevent moisture from penetrating into cracks. It has the characteristic of fundamentally blocking it. In addition, waterproofing injection, which injects organic materials such as urethane epoxy into cracks, is used, but these materials, like the preemptive method of installing PVC waterproofing materials, are used due to material heterogeneity with concrete (different linear expansion coefficient). As a result, it poses the problem of reducing the order effect from a long-term perspective. In addition, even when gaps occur between concrete structures due to new construction or uneven ground settlement, organic materials show different behavior from concrete, and overall defects are frequently confirmed. In particular, the waterproofing method requires quite complex processes such as surface treatment, and if damage occurs in the waterproofing layer, there is also the problem of expanding water leakage in that area.

[Prior patent literature]

- Korean Patent No. 10-1114238 (2012.02.02.)

- Korean Patent No. 10-0531520 (2005.11.21.)

The present invention is a material for preventing leaks and defects in construction joints of structures, and aims to provide a method of manufacturing and constructing joint repair material shotcrete containing a crack self-healing ring instead of using conventional organic water stoppers, water stoppers, and waterproof plates. do.

In order to solve the above problems, the present invention provides ring aggregates based on inorganic materials, ring aggregates based on biomineral-forming bacteria, ring aggregates based on highly absorbent fibers, and capsules containing at least one of these aggregates. Alternatively, one or more of these aggregates may be used to mix self-healing ring aggregates coated with a biodegradable membrane in the joint repair material, resulting in hydration reaction or biomineralization when moisture enters the crack at the expansion joint area where the joint material containing the joint repair material is constructed. Provides a method of healing cracks through formation.

In addition, the binder used in mixing the joint repair material is 30 to 40% by weight of one type of ordinary Portland cement, 15 to 25% by weight of fly ash, 40 to 50% by weight of blast furnace slag, and 1 type of ordinary Portland cement, fly ash and blast furnace slag. Provided is a method comprising 2 to 5 parts by weight of an EVA-based polymer based on a total of 100 parts by weight.

In addition, a method is provided wherein the inorganic material-based ring aggregate includes blast furnace slag fine powder or fly ash, calcium hydroxide (Ca(OH) ₂ ) fine powder, alcohol, and an accelerator.

In addition, the composition of the ring aggregate is 63 to 72% by weight of the blast furnace slag fine powder or fly ash, 3 to 12% by weight of the calcium hydroxide fine powder, 15 to 25% by weight of the alcohol, and 1 to 10% by weight of the quick setting agent. Provides a method.

In addition, the alcohol is methyl alcohol, and the quick-setting agent is sodium silicate (Na ₂ SiO ₂ ㆍnH ₂ O).

In addition, the biomineral-forming bacteria-based ring aggregate provides a method comprising a material in which bacteria with biomineral-forming ability are immobilized on a porous body, alcohol, and an accelerator.

In addition, the ring aggregate provides a method wherein the ring aggregate further includes fine powder of blast furnace slag or fly ash and calcium hydroxide (Ca(OH) ₂ ).

In addition, the composition of the ring aggregate includes 52 to 68% by weight of the blast furnace slag fine powder or fly ash, 3 to 12% by weight of the calcium hydroxide fine powder, 5 to 15% by weight of the material on which the bacteria are immobilized, 15 to 25% by weight of the alcohol, and A method is provided, characterized in that the rapid setting agent is used in an amount of 1 to 10% by weight.

It also provides a method wherein the bacteria is Sphingobacterium multivorum, the alcohol is methyl alcohol, and the quick-setting agent is sodium silicate (Na ₂ SiO ₂ ㆍnH ₂ O).

In addition, the highly absorbent fiber-based ring aggregate includes blast furnace slag fine powder, fly ash, calcium sulfoaluminate (CSA)-based expansion material, calcium hydroxide (Ca(OH) ₂ ) fine powder, alcohol, accelerator, materials in which bacteria are fixed to the porous body, and absorbent A method comprising a fiber is provided.

In addition, the composition of the ring aggregate includes 16.5 to 23.5% by weight of the blast furnace slag fine powder, 16.5 to 23.5% by weight of the fly ash, 5 to 10% by weight of the calcium sulfoaluminate (CSA)-based expansion material, and the calcium hydroxide (Ca(OH) ₂ ) 3 to 12% by weight of fine powder, 15 to 25% by weight of the alcohol, 3 to 8% by weight of the quick-setting agent, 3 to 8% by weight of the material in which the bacteria are fixed to the porous body, and 1 to 5% by weight of the absorbent fiber. Provides a method to do so.

In addition, the capsule material is manufactured by mixing 40 to 70 parts by weight of hypromellose (HPMC) and 1 to 5 parts by weight of purified water, has an internal volume of 0.5 to 2 ml, and dissolves within 30 minutes upon contact with moisture at 20 to 40°C. A method characterized by complete dissolution is provided.

In addition, a method is provided wherein the biodegradable membrane coating material is produced by mixing 70 to 100 parts by weight of hypromellose (HPMC), 1 to 5 parts by weight of purified water, and 50 to 100 parts by weight of methyl alcohol.

In addition, the joint repair material is constructed using a shotcrete method, and the ring aggregate is replaced by 2 to 15% by volume of the aggregate volume, and is mixed at a fine aggregate-binder ratio of 2.0 to 2.5 and a water-binder ratio of 25 to 38%. Provides a method to characterize.

In the present invention, the self-healing ring used in mixing expansion joints is undamaged during mixing, and is evenly distributed across the expansion joint cross section where cracks and water leaks frequently occur due to various factors including temperature expansion and drying shrinkage. The effect of water leakage control along with stable healing at the crack occurrence site can be expected.

In addition, in expansion joints of concrete structures, unlike materials with material heterogeneity such as PVC waterproofing materials, joint materials based on the same inorganic material as the concrete material itself are constructed, thereby inducing an integral behavior with the structure of elastic deformation or shrinkage deformation, thereby preventing cracking. Progress can be prevented.

In addition, crack-healing expansion joints constructed in a preemptive manner during expansion joints provide a healing effect on cracks that may occur during the structure use stage (post-concept), thereby minimizing the maintenance of post-processing concepts such as epoxy injection techniques. .

This invention prevents cracks and water leaks in construction joints of precast concrete structures and reinforced concrete structures, ensures the safety of crack healing materials introduced into expansion joints, and increases the healable crack area of crack healing materials. It is possible to control expansion joint cracks that may occur excessively, improve crack healing efficiency and water resistance by applying organic water stoppers or rings without injection materials, and provide an alternative method to the expensive water stopper installation method. Maintenance costs can be reduced by omitting repair processes such as applying and spraying epoxy waterproofing materials, and the maintenance efficiency of reinforced concrete structures can be dramatically improved.

Figure 1 is a schematic diagram showing the shape of a self-healing ring coated with a biodegradable membrane for each of inorganic material-based ring aggregates, biomineral-forming bacteria-based ring aggregates, and highly absorbent fiber-based ring aggregates.
Figure 2 is a photograph showing that when capsules with internal materials are mixed into the mortar mix, the outer capsule is dissolved after curing and the internal materials are distributed in the internal voids of concrete without damaging the surface.
Figure 3 is a diagram schematically showing the shapes of an inorganic double capsule, a bacterial double capsule, and a hybrid double capsule.
Figure 4 is a photograph showing the manufactured self-healing double capsule.
Figure 5 is a graph showing the evaluation results of the water runoff volume and crack healing rate of repair material specimens according to age changes in the performance evaluation experiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted. Throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

In order to achieve the above technical problem, the present invention is a 'method for manufacturing a ring using a cementitious inorganic material for crack healing in construction joints' or 'a method for manufacturing a ring using a bacterial material with biomineral forming ability for crack healing in construction joints' or ' A ring agglomerate manufactured according to the 'Method for manufacturing a highly absorbent fiber-based crack healing ring with the function of crack width control', or a capsule containing one or more of these aggregates, or a self-healing ring (丸) in which one or more of these aggregates is coated with a biodegradable membrane. ) Agglomerates are used in mixing joint repair materials to heal cracks through hydration reaction or biomineral formation when moisture enters cracks at expansion joints where joint materials containing joint repair materials are constructed.

In the salt damage resistance of joint repair materials containing crack healing rings, internal voids may increase, which may lead to rapid diffusion of chlorine ions. In order to prevent this, in the present invention, 40 to 50% by weight of blast furnace slag fine powder is included to reduce micropores in the hydration product, and chlorine ions are immobilized inside to slow down the diffusion of chlorine ions.

Hereinafter, each ring manufacturing method described above will be described in detail, and then the joint repair material manufacturing method and construction method will be described in detail.

Manufacturing of rings using cement-based inorganic materials to heal cracks in construction joints

In the present invention, the method using ring agglomerates based on inorganic materials uses a self-healing ring containing fine blast furnace slag powder or fly ash, calcium hydroxide (Ca(OH) ₂ ) fine powder, alcohol, and a quick-setting agent to mix joint repair materials, This is a method of healing cracks through a hydration reaction when moisture flows into a crack at an expansion joint where a joint material containing the joint repair material is installed.

In the present invention, the self-healing ring heals the cracked area through a hydration reaction when moisture enters the cracked area when the cement-based inorganic material that makes up the ring occurs when a crack occurs in the expansion joint area after the construction of the joint material when mixing the joint repair material.

These self-healing rings are made by sequentially spraying alcohol and a quick-setting agent on fine powders of blast furnace slag or aggregates of inorganic materials containing fly ash and calcium hydroxide during the ring manufacturing process and hardening them into a ring shape, making them inorganic with the same properties as the cement composite material of concrete structures. Based on the material, it is non-reactive when mixing joint repair materials, that is, the hydration reaction is suppressed within a short period of time during the mixing process of joint repair materials, and after a long period of time has elapsed in the concrete structure after solidification, the cohesion due to alcohol and quick setting agent is weakened, causing expansion. When moisture enters the crack occurring area of the joint, the surface of the ring-shaped aggregate easily peels off or collapses, thereby effectively inducing a hydration reaction of the cement-based inorganic material.

In this way, the combination of ingredients of the self-healing ring, which maintains the non-reactivity of the inorganic material when mixing the joint repair material and controls the reactivity to realize an effective hydration reaction of the inorganic material when cracking the expansion joint area, is blast furnace slag fine powder or fly ash, It was confirmed that it was ideal to include calcium hydroxide (Ca(OH) ₂ ) fine powder, alcohol, and a quick-setting agent. In this case, in order to maximize the reactivity control ability, 63 to 72% by weight of fine powder of blast furnace slag or fly ash and 3 to 12% by weight of fine calcium hydroxide powder were used. , it can be made to have a composition of 15 to 25% by weight of alcohol and 1 to 10% by weight of quick setting agent, preferably 63 to 70% by weight of blast furnace slag fine powder or fly ash, 5 to 12% by weight of calcium hydroxide fine powder, and 17 to 23% by weight of alcohol. % and 3 to 7 wt% of quick-setting agent.

Here, the specific properties of the material for maximizing reactivity control ability are as follows. That is, the blast furnace slag fine powder has a density of 2.5 to 3 g/cm3 and a fineness of 4,000 to 10,000 cm2/g, and the fly ash has a density of 1.8 to 2.1 g/cm3 and a fineness of 3,000 to 8,000 cm2/g. , the calcium hydroxide fine powder has a purity of 98% or more, the alcohol is most preferably methyl alcohol with a concentration of 80 to 99% (v/v), and the quick-setting agent is a silicate-based liquid quick-setting agent with a density of 1.1 to 1.4 g/cm3. It was confirmed that sodium silicate (Na ₂ SiO ₂ ㆍnH ₂ O) was the most preferable.

In the present invention, the self-healing ring is manufactured through the process of sequentially spraying alcohol and an accelerator on blast furnace slag fine powder or an aggregate of an inorganic material containing fly ash and calcium hydroxide and hardening it into a ring shape.

That is, in the present invention, the production of a self-healing ring includes the steps of (a) adding blast furnace slag fine powder or fly ash and calcium hydroxide (Ca(OH) ₂ ) into a ventilation fan and rotating and mixing them; (b) spraying alcohol to produce agglomerated material in the form of a ring; and (c) spraying and hardening an accelerator on the surface of the ring-shaped material; including, in the process of mixing the self-healing ring joint repair material, the hydration reaction is suppressed within a short time, and after a long period of time has elapsed in the concrete structure after solidification. makes it possible to easily manufacture a self-healing ring that has the property of effectively inducing a hydration reaction of the cement-based inorganic material when moisture enters the crack occurrence area of the expansion joint.

At this time, the size of the self-healing ring produced may have an average diameter of 0.5 to 5 mm, and preferably 1 to 2 mm.

[Example of manufacturing pills based on inorganic materials]

65% by weight of blast furnace slag fine powder (density 2.8 g/cm3 and fineness 5,000 to 6,000 ㎠/g) and 10% by weight calcium hydroxide fine powder (purity 99%) were mixed with a ventilation fan (D-350 mm) rotating at a speed of 30 rpm. After putting it in a circular fan rotary ventilation machine and rotating and mixing for about 1 minute, methyl alcohol (85% (v/v) concentration) was sprayed at a volume of 20 ml/time at a content of 20% by weight using a compression sprayer, Using a compression sprayer, spray 5% by weight of sodium silicate (density 1.25 g/cm3) as a silicate-based liquid quick-setting agent on the surface of the material aggregated in the form of a ring at a volume of 10 ㎖/time, and then harden to average Self-healing rings with a diameter of 1 to 2 mm were prepared.

Manufacturing of rings using bacteria with biomineral forming ability for crack healing in construction joints

In the present invention, the method using ring aggregates based on biomineral-forming bacteria uses a self-healing ring containing a material in which bacteria with biomineral-forming ability are fixed to a porous body, alcohol, and an accelerator to mix joint repair materials, This is a method of healing cracks through the formation of biominerals from the bacteria when moisture flows into the crack at the expansion joint where a joint containing a repair material is installed.

In the present invention, the self-healing ring is formed when a crack occurs in the expansion joint after the construction of the joint material when mixing the joint repair material, and the bacteria that make up the ring have the ability to form biominerals. The material fixed to the porous body reacts to form biominerals when moisture enters the crack occurrence area. Heal the cracked area through

Here, the self-healing ring further contains fine powder of blast furnace slag or fly ash and calcium hydroxide (Ca(OH) ₂ ), thereby healing complex cracks through the hydration reaction of cement-based inorganic materials at the crack occurrence site along with the biomineral formation reaction of bacteria. It is also possible.

These self-healing rings are made by sequentially spraying alcohol and an accelerating agent onto the materials in which bacteria with the ability to form biominerals are fixed to a porous body and the aggregates of inorganic materials including fine powders of blast furnace slag or fly ash and calcium hydroxide during the manufacturing process of the rings, thereby hardening them into a ring shape. As a result, it is non-reactive when mixing joint repair materials based on an inorganic material with the same properties as the cement composite material of the concrete structure, that is, the hydration reaction is suppressed within a short period of time during the mixing process of joint repair materials, and after solidification, it does not remain in the concrete structure for a long time. Afterwards, the cohesion caused by alcohol and accelerators is weakened, and when moisture enters the cracks of the expansion joint, the surface of the ring-shaped aggregate easily peels off or collapses, effectively inducing the biomineral formation reaction of bacteria and the hydration reaction of cement-based inorganic materials. It becomes possible.

In this way, when mixing joint repair materials, the non-reactivity of bacteria and inorganic materials is maintained, and when cracks occur in the expansion joint area, self-healing is used to control the reactivity by implementing an effective biomineral formation reaction of bacteria and an effective hydration reaction of inorganic materials. The combination of components of the ring ideally includes a material in which bacteria with the ability to form biominerals are fixed to a porous body, alcohol, and a quick setting agent, and furthermore, it further includes fine powder of blast furnace slag or fly ash and calcium hydroxide (Ca(OH) ₂ ). It was confirmed to be desirable, and in this case, in order to maximize the reactivity control ability, 52 to 68% by weight of the blast furnace slag fine powder or fly ash, 3 to 12% by weight of the calcium hydroxide fine powder, 5 to 15% by weight of the material on which the bacteria were immobilized, and 15% by weight of the alcohol. It may have a composition of 25 to 25% by weight and 1 to 10% by weight of the quick setting agent, preferably 52 to 60% by weight of the blast furnace slag fine powder or fly ash, 5 to 12% by weight of the calcium hydroxide fine powder, and the bacteria immobilized. It may have a composition of 7 to 13% by weight of the material, 17 to 23% by weight of the alcohol, and 3 to 7% by weight of the quick-setting agent.

Here, the specific properties of the material for maximizing reactivity control ability are as follows. That is, the blast furnace slag fine powder has a density of 2.5 to 3 g/cm3 and a fineness of 4,000 to 10,000 cm2/g, and the fly ash has a density of 1.8 to 2.1 g/cm3 and a fineness of 3,000 to 8,000 cm2/g. , the calcium hydroxide fine powder has a purity of 98% or more, the alcohol is most preferably methyl alcohol with a concentration of 80 to 99% (v/v), and the quick-setting agent is a silicate-based liquid quick-setting agent with a density of 1.1 to 1.4 g/cm3. It was confirmed that sodium silicate (Na ₂ SiO ₂ ㆍnH ₂ O) was the most preferable.

In addition, in the present invention, as a porous material for fixing bacteria, a porous material with excellent cation exchange ability may be used, for example, one or more selected from the group consisting of expanded vermiculite, urethane, perlite, and hydrogel may be used, Preferably expanded vermiculite can be used. In the case of the expanded vermiculite, it is preferable to use one with a density of 0.2 to 0.3 g/cm3 to maximize immobilization efficiency.

The materials for fixing bacteria presented in the present invention have the property of adsorbing organic matter by exchangeable cations (Mg ²⁺ , Ca ^{2+ ,} etc.) present on the surface of the material, thereby providing bacteria and organic nutrients (medium components) necessary for bacterial growth. Absorb. In addition, with a pH of 6 to 9, it is the most ideal material for creating an optimal environment for the growth of microorganisms.

For the adsorption of bacteria using the porous material, a immersion process in a container can be used. For optimal absorption efficiency of bacteria in the immersion process, 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the bacterial culture solution. This content can be carried out so that the porous material is completely immersed.

Additionally, the immersion process may be performed under negative pressure conditions. As the immersion process is performed under negative pressure conditions, the air present inside the porous material is released, allowing the bacterial culture to easily penetrate into the immobilization material, that is, the immobilization material can contain not only bacteria but also a large amount of moisture and medium nutrients.

The negative pressure condition may be applied by applying a negative pressure of 1 to 50 torr, preferably 10 to 30 torr, for 10 to 100 minutes, preferably 20 to 50 minutes. At this time, it is desirable to maintain the humidity between 50 and 70%RH and the temperature between 10 and 30°C.

Here, the bacterial culture solution is added to the container, the porous material is immersed, and the bacterial culture solution is immobilized under negative pressure conditions. By driving the rotating fan provided at the bottom of the container, the bacteria are stirred by stirring the immobilization material that can be introduced into the culture solution and suspended. and culture medium nutritional elements can be evenly mixed and immobilized.

The bacteria used in the negative pressure stirring type immobilization method described above are not particularly limited as long as they are suitable for the immersion process using the porous material under negative pressure stirring conditions, but Sphingobacterium multivorum is preferably used under negative pressure stirring conditions. When used in the immersion process using a porous material, a self-healing ring was manufactured using it, and it was confirmed that the biomineral formation reaction of bacteria is effectively implemented when moisture enters the cracked area of the joint after mixing and curing the joint repair material.

Here, in the present invention, as a result of studying the composition of a special medium to create an optimal culture environment for the bacteria, the Sphingobacterium multivorum contains 0.05 to 1 g of yeast extract based on 1 liter of purified water. , It was confirmed that it was ideal to be cultured at a concentration of 108 to 1010 cells/ml in an incubator with a pH of 5 to 9 and a 5 to 50°C environment in a medium containing 1 to 10 g of peptone and 10 to 30 g of urea. did.

In the present invention, the production of the self-healing ring is a process in which bacteria with the ability to form biominerals are sequentially sprayed with alcohol and an accelerator on an aggregate containing a material fixed to a porous body and fine powder of blast furnace slag or fly ash and calcium hydroxide, and hardening it into a ring shape. It is carried out through.

That is, in the present invention, the production of a self-healing ring includes the steps of (a) inserting a material in which bacteria with the ability to form biominerals are fixed to a porous body into a ventilation fan and rotating and mixing it; (b) spraying alcohol to produce agglomerated material in the form of a ring; And (c) spraying and curing an accelerator on the surface of the ring-shaped material; Including, in the process of mixing the self-healing ring joint repair material, the biomineral formation reaction of bacteria and the hydration reaction of the inorganic material are suppressed within a short time, After a long period of time has elapsed in the concrete structure after solidification, it is possible to easily manufacture a self-healing ring that has the property of effectively inducing the biomineral formation reaction of bacteria and the hydration reaction of cementitious inorganic materials when moisture enters the cracked area of the expansion joint. make it possible

At this time, the size of the self-healing ring produced may have an average diameter of 0.5 to 5 mm, and preferably 1 to 2 mm.

[Example of manufacturing pills based on biomineral forming bacteria]

(1) Manufacturing of a porous material with immobilized bacteria using an internally stirred sterilized negative pressure container

Sphingobacterium multi in an incubator at pH 6 to 8 and 35 to 45°C in a medium containing 3 g of yeast extract, 5 g of peptone and 20 g of urea based on 1 liter of purified water. Sphingobacterium multivorum was inoculated and the bacterial culture cultured at a concentration of 10 ⁹ cells/ml was fixed on expanded vermiculite with a density of 0.25 g/cm3, which has a porous structure with countless pores, using the following method.

Put the Sphingobacterium multivorum culture solution prepared above into an internal stirring type sterilized negative pressure container, 10 parts by weight of expanded vermiculite per 100 parts by weight of the bacterial culture solution is immersed in the culture solution, and then close the door, The valve was adjusted to create a negative pressure environment of about 15 torr, and adsorption was performed for 30 minutes by driving a rotating fan at a speed of 300 rpm, and then the expanded vermiculite with fixed bacteria was recovered.

(2) Manufacturing of pills based on biomineral forming bacteria

75% by weight of expanded vermiculite with immobilized bacteria prepared above was put into a ventilation fan (D-350 mm round fan rotary ventilation fan) rotating at a speed of 30 rpm, rotated and mixed for about 1 minute, and then compressed spray was applied. Spray methyl alcohol (85% (v/v) concentration) at a content of 20% by weight at a volume of 20 ml/time using a compression sprayer on the surface of the material aggregated in the form of a ring, and spray 10 ml/time using a compression sprayer. A self-healing ring with an average diameter of 1 to 2 mm was prepared by spraying 5% by weight of sodium silicate (density 1.25 g/cm3) as a silicate-based liquid quick-setting agent and then curing it.

Fabrication of highly absorbent fiber-based crack healing pills with the function of crack width control

In the present invention, the method using highly absorbent fiber-based ring aggregates includes blast furnace slag fine powder, fly ash, calcium sulfoaluminate (CSA) expansion material, calcium hydroxide (Ca(OH) ₂ ) fine powder, alcohol, quick-setting agent, and bacteria. A self-healing ring containing a material fixed to a porous body and absorbent fibers is used to mix a joint repair material, and biominerals of cement-based inorganic materials and bacteria are formed when moisture flows into a crack at an expansion joint where a joint material containing the joint repair material is constructed. This is a method of healing and controlling cracks through .

Materials for manufacturing a highly absorbent fiber-based crack healing ring with the function of crack width control include, for example, blast furnace slag fine powder with a density of 2.8 g/cm3 and a fineness of 4,000 cm2/g or more, a density of 1.95 g/cm3 and a fineness of 3,000 cm2/g. Fly ash with a density of 2.8 to 2.9 g/cm3 and a fineness of 2500 cm2/g or more, a CSA-based expansion material with a CaO content of 48 to 53% by weight, calcium hydroxide (Ca(OH) ₂ ) fine powder with a purity of 98% or more, concentration A silicate-based liquid quick-setting agent with a density of 1.25 g/cm3 containing 84% (v/v) or more of methyl alcohol and sodium silicate (Na ₂ SiO ₂ ㆍnH ₂ O) as main ingredients can be used.

As a biomineral-forming bacterial material , Sphingobacterium multivorum culture medium is inoculated into a medium consisting of Beast extract and Peptone and cultured at a concentration of ¹⁰⁹ cells/mL in an incubator at 5 to 50°C, and is injected into countless pores. A material immobilized on expanded vermiculite with a porous structure and a density of 0.25 g/cm3 can be used. The composition of the medium for cultivating Sphingobacterium multivorm bacteria is the same as in the production of rings using bacteria capable of forming biominerals. Fixation of the bacterial culture to the immobilization material is accomplished through adsorption using a sterilized negative pressure container (10-30 torr, 30 minutes), and the expanded vermiculite upon which the immobilization of the bacterial culture is completed contains not only bacterial cells but also a large amount of moisture and media nutrients. do.

Fibers used for the function of crack width control may be, for example, nylon fibers with a diameter of 0.01 to 0.05 mm, a length of 1.0 mm or less, an elastic modulus of 5,000 MPa or more, a density of 1.1 to 1.2 g/cm3, and a water absorption rate of 2.5% or more. .

The composition for manufacturing a highly absorbent fiber-based crack healing ring includes 16.5 to 23.5% by weight of blast furnace slag fine powder, 16.5 to 23.5% by weight of fly ash, 5 to 10% by weight of CSA expansion material, and calcium hydroxide fine powder with a purity of 98% (v/v) or more. It may be 3 to 12% by weight, 15 to 25% by weight of methyl alcohol, 3 to 7% by weight of silicate quick-setting agent, 3 to 8% by weight of bacterial immobilization material, and 1 to 3% by weight of nylon fiber.

As equipment for producing a highly absorbent fiber-based crack healing ring, a D-350 mm circular fan rotary ventilation machine can be used. Blast furnace slag fine powder, fly ash, CSA expansion agent, calcium hydroxide, and bacteria immobilization material were put into a ventilation fan rotating at a speed of 30 rpm, rotated and mixed for about 1 minute, and then methylated at a volume of 20 mL/time using a compression sprayer. Spray alcohol. The self-healing material, which aggregates into a ring after spraying methyl alcohol, is mixed by scattering nylon fibers on the surface. Afterwards, the silicate-based quick-setting agent is sprayed at a volume of 10 mL/time using a compression sprayer and cured.

[Example of highly absorbent fiber-based pill manufacturing]

(1) Manufacturing of a porous material with immobilized bacteria using an internally stirred sterilized negative pressure container

Sphingobacterium multi in an incubator at pH 6 to 8 and 35 to 45°C in a medium containing 3 g of yeast extract, 5 g of peptone and 20 g of urea based on 1 liter of purified water. Sphingobacterium multivorum was inoculated and the bacterial culture cultured at a concentration of 10 ⁹ cells/ml was fixed on expanded vermiculite with a density of 0.25 g/cm3, which has a porous structure with countless pores, using the following method.

Put the Sphingobacterium multivorum culture solution prepared above into an internal stirring type sterilized negative pressure container, 10 parts by weight of expanded vermiculite per 100 parts by weight of the bacterial culture solution is immersed in the culture solution, and then close the door, The valve was adjusted to create a negative pressure environment of about 15 torr, and adsorption was performed for 30 minutes by driving a rotating fan at a speed of 300 rpm, and then the expanded vermiculite with fixed bacteria was recovered.

(2) Manufacturing of highly absorbent fiber-based pills

20 parts by weight of blast furnace slag fine powder (density 2.8 g/cm3 and fineness 5,000 to 6,000 cm2/g), 20 parts by weight fly ash (density 1.95 g/cm3 and fineness 4,000 to 5,000 cm2/g), calcium sulfoaluminate ( CSA)-based expansion material (contains 25 parts by weight of free lime, 25 parts by weight of calcium sulfoaluminate, and 50 parts by weight of anhydrous gypsum, and 50% by weight of calcium oxide (CaO) content in the calcium sulfoaluminate component), 8 parts by weight, calcium hydroxide fine powder ( Purity 99%) 10 parts by weight and 5 parts by weight of expanded vermiculite with immobilized bacteria prepared above are put into a ventilation fan (D-350 mm round fan rotary ventilation fan) rotating at a speed of 30 rpm and rotated for about 1 minute. After mixing, 20 parts by weight of methyl alcohol (85% (v/v) concentration) is sprayed at a volume of 20 ml/time using a compression sprayer, and a highly absorbent spray is applied to the surface of the material aggregated in the form of a ring. As a fiber, nylon fibers (diameter 0.01 to 0.03 mm, length 0.1 to 1 mm, elastic modulus 10,000 to 20,000 MPa, density 1.1 to 1.2 g/cm3, and water absorption 5 to 7% by weight) are scattered at a content of 2 parts by weight. After mixing, 5 parts by weight of sodium silicate (density 1.25 g/cm3) is sprayed as a silicate-based liquid quick-setting agent at a volume of 10 ml/time using a compression sprayer, and then cured to heal cracks with an average diameter of about 1 mm. A pill was prepared.

How to make self-healing pills with biodegradable membrane coating

In the present invention, as a material for coating a biodegradable membrane, a material prepared by mixing 70 to 100 parts by weight of hypromellose (HPMC), 1 to 5 parts by weight of purified water, and 50 to 100 parts by weight of methyl alcohol can be used, preferably HPMC. One prepared by mixing 80 to 90 parts by weight of lomellose (HPMC), 2 to 4 parts by weight of purified water, and 50 to 100 parts by weight of methyl alcohol can be used.

The solution mixed with the biodegradable membrane coating material produced in this way can be used as a self-healing ring based on cement-based inorganic material, a self-healing ring based on biomineral-forming bacteria, or a highly absorbent fiber-based ring with the function of crack width control. A biodegradable membrane-coated self-healing ring can be produced by spraying it on the outer shell of the crack healing ring. At this time, the self-healing ring aggregate is protected without damage and the ring aggregate is attached to the hardened concrete internal structure. The preferred formation thickness of the biodegradable coating film to ensure even distribution and allow intact ring aggregates to react directly with moisture may be 10 to 50 ㎛, more preferably 20 to 40 ㎛. Figure 1 schematically shows the form of a self-healing ring coated with a biodegradable membrane for each of inorganic material-based ring aggregates, biomineral-forming bacteria-based ring aggregates, and highly absorbent fiber-based ring aggregates.

Manufacturing self-healing double capsules for crack healing in construction joints

In the present invention, the outer capsule material for manufacturing double capsules can be used as a material prepared by mixing 40 to 70 parts by weight of hypromellose (HPMC) and 1 to 5 parts by weight of purified water, preferably hypromellose (HPMC). One prepared by mixing 50 to 60 parts by weight and 1 to 2.5 parts by weight of purified water can be used. The internal volume of the capsule is 0.5 to 2 in order to improve the efficiency of the direct reaction of moisture and crack healing material on the crack surface that occurs after hardening of the expansion joint area, as the ring aggregate that was not damaged during the mixing and pouring process. It is preferably ml, and more preferably 0.5 to 1 ml.

These capsules are used to have the property of dissolving when in contact with moisture. Specifically, capsules that completely dissolve within 30 minutes when in contact with moisture at 20 to 40°C can be used. Table 1 below shows the results of measuring the dissolution rate of the shell capsules used in the experimental examples described later by immersion in water.

Soaking time (minutes) water temperature 20℃ 30℃ 40℃ 0 10 20 30 - -

Accordingly, when the outer capsule is added to the joint repair material mixture, the outer capsule is dissolved, allowing the internal input material to be distributed into the internal pores of the joint repair material without damaging the surface. In Figure 2, when capsules with internal materials are mixed with a joint repair material mix with a unit quantity of 160 kg/㎥ and a flow (a) of 150 mm, the outer capsule dissolves at 1 day after curing, causing surface damage to the internal materials. (b) shows distribution in the internal voids of concrete. These double capsules can be classified into three types, namely, inorganic double capsules, bacterial double capsules, and hybrid double capsules, depending on the type of self-healing ring aggregate introduced therein (see Figure 3), and in Table 2 below, the self-healing ring aggregates are classified into three types. A composition example of a double capsule (internal volume 0.5 to 1 ml) is shown, and Figure 4 shows the self-healing double capsule produced.

Type Self-healing ring aggregate dosage (g) Inorganic self-healing pill Bacteria-based self-healing pills Inorganic double capsule 0.3~0.45 - Bacteria double capsule - 0.25~0.4 Hybrid double capsule 0.15~0.22 0.13~0.2

In the case of an inorganic double capsule, 0.3 to 0.45 g of an inorganic self-healing ring made with a particle diameter of 1 mm or less can be injected into the outer capsule. Additionally, in the case of a bacterial double capsule, 0.25 to 0.4 g of a self-healing ring based on biomineral-forming bacteria manufactured with a particle size of 1 mm or less can be injected into the outer capsule. Additionally, in the case of a hybrid double capsule, an inorganic ring and a bacteria-based ring are mixed and added into the outer capsule, and the added weight may be 0.15 to 0.22 g and 0.13 to 0.2 g, respectively. In the case of hybrid double capsules, crack healing through the hydration reaction of inorganic materials at the site of concrete cracks and crack healing through the biomineral formation of bacteria can be expected at the same time.

Crack healing pill-based self-healing grout repair material

The self-healing joint repair material containing the crack self-healing ring is a mixture developed considering the integrity with concrete and constructability at the construction joint area, and the binder is one type of ordinary Portland cement, fly ash, blast furnace slag fine powder, and polymer powder. It is used. The composition ratio of each material is 30 to 40% by weight of one type of ordinary Portland cement, 15 to 25% by weight of fly ash, and 40 to 50% by weight of blast furnace slag.

In the case of the polymer powder, EVA-based materials can be used to improve the adhesive performance of self-healing joint repair materials, and are mixed at a content of 2 to 5 parts by weight based on a total of 100 parts by weight of the one type ordinary Portland cement, fly ash, and blast furnace slag. It can be. In addition, as a material to prevent deformation such as expansion and contraction of the repair material, polyethylene fibers (average diameter 100 to 150 ㎛, preferably 110 to 130 ㎛) can be mixed in an amount of 0.1 to 0.2 parts by volume based on 100 parts by volume of the total repair material. there is. The fine aggregate may be silica sand, and for example, materials having particle diameters of 0.05 to 0.17 mm, 0.17 to 0.25 mm, and 0.25 to 0.7 mm may be mixed at a weight ratio of 1:0.8 to 1.2:0.8 to 1.2. You can. At this time, the fine aggregate-binder ratio (sand to binder ratio, S/B) may be 2.0 to 2.5. The self-healing crack ring can be made of the above-mentioned materials alone or in combination, taking into account the characteristics and environment of the structure to which the expansion joint is applied. Self-healing rings can be mixed by replacing 2 to 15% by volume of the aggregate volume.

Manufacturing example of crack healing ring-based self-healing joint repair material

A binder was prepared with a composition of 35 parts by weight of type 1 ordinary Portland cement, 20 parts by weight of fly ash, 45 parts by weight of blast furnace slag, and 3 parts by weight of EVA-based polymer, and polyethylene fibers (average diameter 120 ㎛) were added to 100 parts by volume of the total repair material. Prepare to be 0.15 parts by volume, use silica sand (average particle diameter 0.05 mm to 0.7 mm) as fine aggregate so that the fine aggregate-binder ratio (S/B) is 2 by weight, and water-binder ratio (water to binder ratio) , W/B) was mixed to 30% by weight (selectable from 25 to 38% by weight) to prepare a self-healing joint repair material.

The self-healing crack ring was added at a mixing ratio of 5% by volume compared to the aggregate of the joint repair material, and mixed in a mixer to prepare the final joint repair material. The formulation details of the crack healing ring-based self-healing joint repair material are shown in Table 3 below. At this time, the replacement amount of the crack self-healing ring can be varied from 2 to 15% by volume relative to the aggregate, depending on the target performance of the repair material production or the decision of the constructor.

Types of crack healing pills Water-binder ratio (% by weight) Fine aggregate-binder ratio Binder (part by weight) Fiber mixing ratio (volume) Substitution rate of autonomous base oil (volume %) Type 1 Ordinary Portland Cement blast furnace slag fly ash EVA-based polymer Highly absorbent fiber-based crack healing pill 25~38 2~2.5 30~40 40~50 15~25 2~5 0.1~0.2 2~15 Crack healing pill based on inorganic materials 25~38 2~2.5 30~40 40~50 15~25 2~5 0.1~0.2 2~15 Bacteria-based crack healing pills 25~38 2~2.5 30~40 40~50 15~25 2~5 0.1~0.2 2~15 Self-healing pills with biodegradable membrane coating 25~38 2~2.5 30~40 40~50 15~25 2~5 0.1~0.2 2~15 Self-healing double capsule 25~38 2~2.5 30~40 40~50 15~25 2~5 0.1~0.2 2~15

Crack self-healing grout repair construction method

In most cases of concrete construction joints, rebar is exposed during the process of dividing sections for concrete pouring, so the plastering method using manpower is not appropriate for constructing and pouring joint repair materials at the interface of construction joints. Accordingly, the construction of crack self-healing joint repair materials uses the shotcrete method using mechanical spray pouring. A mobile mixer with a capacity of 10 to 60 L and a monopump with a pressure of 300 to 1,000 rpm and 40 to 100 bar are the basic transport equipment for joint repair materials, and an air compressor of 100 to 1,000 kPa is used for compression spraying. do. Additionally, a portable module with an integrated mixer, pump, and compression sprayer can be used to facilitate movement of workers to construction joints and installation of crack healing joint repair materials. The construction of crack self-healing joint repair material using the mechanical spray pouring method can be comprised of a one-time or two-time construction procedure. If the construction joint is located on the outer wall of an underground structure or repair facility, the crack at the crack occurrence site may occur. Apply twice to improve healing performance and ensure safe water blocking effect. In addition, the construction joint of a general concrete structure can be constructed with only one construction. When performing two applications, the first stage spraying process is done with a thin spray of 1 to 3 mm to remove voids in the substrate and increase adhesion. Second-stage spraying is done within 90% of the design thickness, including the first-stage thickness, and the total construction thickness can vary from a maximum of 30 to 100 mm depending on the judgment of the designer or constructor. When performing only one-time construction, construct with a thickness that satisfies the initially determined joint repair material construction thickness.

Evaluation of crack healing performance of crack healing ring-based self-healing grout repair material

The joint repair material manufactured above was subjected to performance evaluation according to test standards, and the results are shown in Table 4 below. In Table 4, the mortar for construction joints is a case where the crack healing ring is not mixed, and the results are shown together for comparative evaluation.

test subject Test Methods Test result Crack healing pill-based self-healing grout repair material General repair materials Highly absorbent fiber-based crack healing pill Crack healing pill based on inorganic materials Bacteria-based crack healing pills Self-healing pills with biodegradable membrane coating Self-healing double capsule Bending strength (MPa) KS F 4042 : 2012
2.2
1.7 8.8 9.2 9.0 8.7 8.6 8.7 Compressive strength (MPa) 52.4 51.2 51.5 49.9 48.8 48.5 Adhesion strength Standard conditions (MPa) 2.2 2.1 2.2 2.3 1.9 2.0 After repeating hot and cold (MPa) 1.6 1.5 1.5 1.7 1.4 1.3 Alkali resistance (MPa) 46.4 45.5 46.1 44.4 43.7 42.5 Neutralization resistance (mm) 0.8 0.8 0.7 0.6 0.8 1.5 Water permeability (g) 2.8 2.9 2.9 4.1 3.7 6.4 Water absorption coefficient (kg/m ² h ^0.5 ) 0.09 0.08 0.06 0.07 0.11 0.14 Moisture penetration resistance (m) 0.9 0.8 0.5 0.7 0.9 1.3 Resistance to chloride ion penetration (coulombs) 300 360 315 395 385 455 Length change rate (%) 0.03 0.03 0.05 0.05 0.04 0.06

Referring to Table 4, it can be seen that the joint repair material according to the present invention exhibits equal or better performance in all items compared to the quality performance of general repair materials (KS F 4042) used to fill construction joints and prevent water leaks. The water absorption coefficient and moisture permeability of the self-healing joint repair material mixed with highly absorbent fiber-based rings were found to be reduced by 35% and 31%, respectively, compared to the values of general repair materials. In addition, in the same mix, the neutralization depth is half that of general repair materials, and the chloride ion penetration resistance is 65% of that of general repair materials. As a result, it can be confirmed that the quality performance of the joint repair material mixed with the crack healing ring satisfies all the quality standards required by KS F 4042 regardless of the type of crack healing ring.

Meanwhile, a split crack with a width of 0.3 mm was induced in the prepared joint repair material specimen, and crack healing performance was evaluated through a hydrostatic water permeability test, and the results are shown in FIG. 5. The crack healing rate of the crack-induced test specimen was calculated based on the evaluation results of the runoff water volume at each age that decreases compared to the initial runoff water volume after crack induction.

Referring to Figure 5, the crack healing rate of general construction joint mortar at 56 days is 49%, while in the case of self-healing joint repair material based on crack healing ring, the crack healing rate at 56 days is 49% regardless of the type of crack healing ring. All test specimens exceeded 90%. The self-healing joint repair material mixed with fiber-based self-healing pills showed the highest crack healing rate at 95% at 56 days.

Preferred embodiments of the present invention have been described in detail above. The description of the present invention is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing its technical spirit or essential features.

Accordingly, the scope of the present invention is indicated by the claims described later rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. must be interpreted.

Claims (5)

A biomineral-forming bacteria-based ring aggregate, a capsule into which the biomineral-forming bacteria-based ring aggregate is added, or a self-healing ring aggregate containing the biomineral-forming bacteria-based ring aggregate coated with a biodegradable membrane. A method used in mixing joint repair materials to heal cracks through the formation of biominerals when moisture flows into the cracks at the expansion joint area where the joint material containing the joint repair materials is constructed,
The binder used in mixing the joint repair material is 30 to 40% by weight of type 1 ordinary Portland cement, 15 to 25% by weight of fly ash, 40 to 50% by weight of blast furnace slag, and a total of the type 1 ordinary Portland cement, fly ash and blast furnace slag. Contains 2 to 5 parts by weight of EVA-based polymer, based on 100 parts by weight,
The biomineral-forming bacteria-based ring aggregate includes 52 to 68% by weight of blast furnace slag fine powder or fly ash, 3 to 12% by weight of calcium hydroxide fine powder, 5 to 15% by weight of a material in which bacteria with biomineral forming ability are fixed to a porous body, A method comprising 15 to 25% by weight of alcohol and 1 to 10% by weight of a quick-setting agent. According to paragraph 1,
The method is characterized in that the bacteria is Sphingobacterium multivorum, the alcohol is methyl alcohol, and the quick-setting agent is sodium silicate (Na2SiO2·nH2O). According to paragraph 1,
The capsule material is manufactured by mixing 40 to 70 parts by weight of hypromellose (HPMC) and 1 to 5 parts by weight of purified water, has an internal volume of 0.5 to 2 ml, and is completely destroyed within 30 minutes upon contact with moisture at 20 to 40 ° C. A method characterized in that it dissolves. According to paragraph 1,
The biodegradable membrane coating material is characterized in that it is produced by mixing 70 to 100 parts by weight of hypromellose (HPMC), 1 to 5 parts by weight of purified water, and 50 to 100 parts by weight of methyl alcohol. According to paragraph 1,
The joint repair material is constructed using a shotcrete method, and the ring aggregate is replaced by 2 to 15% by volume of the aggregate volume, and is mixed at a fine aggregate-binder ratio of 2.0 to 2.5 and a water-binder ratio of 25 to 38%. How to do it.