KR102349609B1 - Admixture Composition for Self-Healing Concrete, Manufacturing Method thereof, and Self-Healing Concrete Composition having such Admixture Composition - Google Patents

Abstract

The present invention relates to a carbonation accelerated reaction high activity self-healing admixture mixed when manufacturing a self-healing concrete composition, a manufacturing method thereof, and a self-healing concrete composition having the same. The carbonation accelerated reaction high activity self-healing admixture may cause a carbonation accelerated reaction to maximize a self-healing effect by applying a mechanochemical reaction process of organic/inorganic materials which allows the admixture to have a multiple lamellar structure of high activity generated by grinding and mixing, mechanochemical reaction between mixed powders, and mutual operation between dynamic energy and chemical energy.

Description

Carbonation promoting reaction highly active self-healing admixture, manufacturing method thereof, and self-healing concrete composition comprising same

The present invention relates to a self-healing admixture, a method for manufacturing the same, and a self-healing concrete composition comprising such a self-healing admixture. Specifically, when preparing an admixture to be incorporated into the self-healing concrete composition By applying the mechanochemical reaction process of inorganic materials, it has a highly active multi-lamellar structure created through the mechanochemical reaction between the pulverized mixing and the resulting mixed powder and the resulting interaction between mechanical energy and chemical energy. A "carbonation promoting reaction high activity self-healing admixture" that can maximize the self-healing effect by causing a carbonation promoting reaction, a "manufacturing method" for manufacturing such a self-healing admixture, and a "concrete composition comprising such a self-healing admixture" "It's about In particular, the present invention is derived as a research result of a research project (task number 21SCIP-C159059-02) supported by the Ministry of Land, Infrastructure and Transport/Korea Agency for Infrastructure Technology Advancement (This work is supported by the Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 21SCIP-C159059-02)).

When a crack occurs in a concrete structure, self-healing concrete is being developed that repairs the crack by itself with the material inside the concrete and maintains its original function without any external artificial measures. Korean Patent Registration No. 10-1308084 discloses an example of the prior art for self-healing concrete.

In the case of the conventional self-healing concrete composition, it takes at least 28 days or more for the healing performance to be expressed in the damaged part of the concrete structure constructed using it, which is not suitable for healing the cracks that occur in the initial stage. not. This limitation of the prior art is due to the fact that the admixture is mixed in a state that is not solidified to a large extent, and there is an urgent need to develop an admixture that can overcome the limitations of the prior art.

Republic of Korea Patent Publication No. 10-1308084 (2013. 09. 12. Announcement).

The present invention was developed to overcome the limitations of the prior art as described above, and it can exhibit excellent crack recovery and self-healing effect accordingly, and in particular, it reduces the time for healing (recovery) of initial cracks and complete healing of damaged parts. An object of the present invention is to provide a self-healing admixture that can be shortened within one day, a manufacturing method thereof, and a self-healing concrete composition comprising the same.

In the present invention, in order to achieve the above object, it has a composition consisting of 45 to 84% by weight of Mag carbon, 6 to 20% by weight of a carbonation reaction accelerator, 5 to 20% by weight of a Ca-based layered mineral, and 5 to 15% by weight of an organic acid additive to be; performing a primary MC (mechanochemical) process of mixing mag carbon, a carbonation reaction accelerator, and a Ca-based layered mineral and grinding at a grinding speed of 150 to 200 rpm and grinding for 5 to 9 hours; recovering powder by sieving the resultant of the first MC process; and a second MC process of mixing the recovered powder with an organic acid additive and grinding at a grinding speed of 120 to 150 rpm and grinding for 2 to 4 hours. A healing admixture is provided.

The self-healing admixture according to the present invention has a composition consisting of 65% by weight of Mag carbon, 10% by weight of a carbonation reaction accelerator, 15% by weight of a Ca-based layered mineral, and 10% by weight of an organic acid additive; In the step of performing the first MC process, 65% by weight of Magcarbon, 10% by weight of a carbonation reaction accelerator, and 15% by weight of Ca-based layered minerals are mixed; In the step of performing the second MC process, 10% by weight of the organic acid additive may be mixed and prepared.

In the present invention, in order to achieve the above object, a method for manufacturing a self-healing admixture according to the present invention and a self-healing concrete composition comprising the self-healing admixture according to the present invention are provided.

According to the present invention, in manufacturing the self-healing admixture, by applying the mechanochemical reaction process of organic/inorganic materials, the mechanochemical reaction between the pulverized mixing and the resulting mixed powder and the resulting mechanical energy and chemical energy It has a highly active, multi-lamellar structure created through the interaction of

Therefore, the self-healing admixture according to the present invention and the self-healing concrete composition prepared including the same not only exhibit an excellent crack healing effect, but also shorten the time for initial crack healing and complete healing of damaged parts to less than 14 days, and accordingly Excellent self-healing performance can be expressed at an early stage.

1 is a schematic diagram showing the process of steps 1 to 3 for producing a self-healing admixture according to the present invention.
2 is a schematic diagram showing a series of processes of generating a crack in the form of a cleavage in a specimen and measuring the water permeability in a state where the crack width is controlled.
Figure 3 is a drawing substitute photograph showing the cutting of the specimen.
4 (a) and (b) are drawings instead of pictures sequentially showing the process of inducing forced cracking in the specimen, respectively.
5 is a picture substitute for a drawing showing a state of measuring the amount of runoff.
Figure 6 is a drawing substitute photograph showing a crack recovery image for the Example of Table 2 corresponding to the test body containing the self-healing admixture according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described. However, the technical spirit of the present invention and its core configuration and operation are not limited to the embodiments. In particular, throughout this specification, the term "concrete composition" refers to both a concrete composition in the traditional sense including both coarse aggregate and fine aggregate, as well as a mortar composition containing no coarse aggregate, and a cement composition containing no aggregate at all. used in an inclusive sense.

The self-healing admixture according to the present invention for the production of a self-healing concrete composition is 45 to 84% by weight of mag carbon (MgO-C) having a size of 2 mm or less, 6 to 20% by weight of a carbonation reaction accelerator, 5 to 20% by weight of a Ca-based layered mineral % by weight, and has a composition consisting of 5 to 15% by weight of an organic acid additive.

In particular, the self-healing admixture according to the present invention is prepared by mixing Mag carbon, a carbonation reaction accelerator and a Ca-based layered mineral in the above composition range, and then performing the primary mechanochemical (MC) under the conditions of 150 to 200 rpm and 5 to 9 hours. ) process, and after collecting the powder by sieving the resultant, the organic acid additive in the composition range described above is mixed into the recovered powder, and the second MC process is performed under the conditions of 120 to 150 rpm and 2 to 4 hours. produced by proceeding.

Magcarbon (MgO-C) is a material that forms a highly active multi-lamellar structure by physical and chemical energy in the MC process while serving to form a seed of a self-healing admixture. When mag carbon is incorporated in less than 45% by weight, the function as a seed that allows the characteristics of self-healing admixture to be expressed in the MC process is weakened and it is difficult to form a lamellar structure. The content of other compositional materials injected into the furnace is excessively lowered, thereby inhibiting the expression of self-healing performance. Therefore, in the present invention, mag carbon (MgO-C) is incorporated in an amount of 45 to 84% by weight. In particular, in the present invention, the magnet carbon having a size of 2 mm or less is used. When the size of the magnet carbon exceeds 2mm, the size of the seed formed through the combination with other materials of the self-healing admixture is too large, and the formation of a self-healing product by the self-healing admixture is reduced.

The carbonation reaction accelerator is a material for promoting the elution of calcium ions and securing a quick reaction with calcium ions, which are necessary when a self-healing product is made by the carbonation reaction. Since the expression of the effect is reduced, it is difficult to secure self-healing performance, and when it exceeds 20% by weight, the carbonation reaction proceeds excessively rapidly and reacts rapidly with calcium ions eluted from the surface, so that it remains on the exposed surface. Since the elution of ions and the carbonation reaction are not smooth, it is difficult to secure the required self-healing performance. Therefore, in the present invention, the carbonation reaction accelerator is incorporated in an amount of 6 to 20% by weight.

Ca-based layered minerals have a function of capturing water containing calcium ions eluted from the cracks when water flows in/leaks through the cracks. Water) is continuously discharged to form a self-healing product through carbonation reaction. The self-healing product is a calcium carbonate produced by the carbonation reaction of the calcium component, and the formation of a self-healing product can increase under the condition that the elution of calcium ions is high at the crack site or there is sufficient material that provides calcium ions. will be. When the Ca-based layered mineral is incorporated in less than 5% by weight ^{, the concentration of calcium ions (Ca 2+} ) that can be eluted from the Ca-based layered mineral becomes low, or the water containing calcium ions eluted from the hardened body at the cracking site is converted to Ca. The amount of calcium ion-containing water that layered minerals absorb and have is reduced. In this case, it is difficult to secure self-healing performance due to insufficient provision of calcium ions required for carbonation reaction, low formation of self-healing products.

On the other hand, when the Ca-based layered mineral is mixed in excess of 20% by weight, there is a problem in that the workability (fluidity) of the self-healing concrete composition is lowered due to excessive moisture absorption properties. Therefore, in the present invention, the Ca-based layered mineral is incorporated in an amount of 5 to 20% by weight.

The organic acid additive is a composition quality for securing concrete or mortar waterproofing performance, and when it is mixed in less than 5% by weight, it is difficult to secure the waterproofing performance of the sphere, and when it is mixed in more than 15% by weight, the strength of concrete or mortar may be reduced. Therefore, in the present invention, the organic acid additive is incorporated in an amount of 5 to 15% by weight.

In manufacturing the self-healing admixture of the present invention using the above composition material, the following three-step process is performed.

(Step 1) Primary mechanochemical process

The first mechanochemical process is carried out by mixing and pulverizing mag carbon, a carbonation reaction accelerator and Ca-based layered mineral in the composition range described above, followed by mixing and pulverizing under the conditions of 150 to 200 rpm and 5 to 9 hours. For convenience, the mechanochemical process is described as "MC process". In the present invention, Mag carbon, carbonation reaction accelerator, and Ca-based layered mineral are measured, mixed, and pulverized within the above composition range. The mixture is pulverized by a pulverizer to make it finer.

Pulverization is a process of refining materials by mechanical external force, and it has been found that the energy input for pulverization, that is, pulverization energy, is used not only for the particle size of the object, but also for the crystal structure of the solid, the interfacial state, and the chemical reaction with surrounding materials. This is commonly referred to as "mechanochemistry". When mechanical energy such as pulverization energy is applied to an object in the form of pulverization, the particles are deformed and subdivided, and the surface area increases as well as the surface energy. As the active surface increases, the interaction between the particle and the adjacent fluid, and the interaction between the particle and the particle is significantly increased, thereby increasing the reactivity. A phenomenon in which the physicochemical properties of an object pulverized by mechanical energy change in this way is called a “mechanochemical effect”, and a reaction that exerts such a mechanochemical effect is called a “mechanochemical reaction”. That is, the effect and reaction of forming a new type of compound due to the physical force applied to the surface by the impact between the powder and the powder or solid and the resulting energy are called mechanochemical effects and mechanochemical reactions, respectively. Materials that have undergone mechanochemical effects and mechanochemical reactions are not formed by artificially applying separate thermal energy from the outside.

In the present invention, according to the above grinding conditions, mag carbon, carbonation reaction accelerator and Ca-based layered mineral are weighed, mixed, and pulverized in the above composition range to be pulverized, and in this grinding process, the mechanochemical effect and mechanochemical When the reaction proceeds, this is called "the primary mechanochemical process".

(Step 2) Powder recovery process

In this way, the result of the first mechanochemical process is sieved to control the particle size and then recovered as a powder.

(Step 3) Second mechanochemical process

After adding the organic acid additive to the recovered powder in the above composition range, the secondary MC process is performed by mixing and pulverizing under the conditions of 120 to 150 rpm and 2 hours. Specifically, the powder recovered by step 2 is mixed with an organic acid additive in the above composition range and pulverized, and further pulverized by a pulverizer under the conditions of a pulverization speed of 120 to 150 rpm and a pulverization proceeding for 2 to 4 hours to refine it. By doing so, the above mechanochemical effect and mechanochemical reaction proceed,

1 is a schematic diagram showing the process of the above-described steps 1 to 3 for manufacturing a self-healing admixture according to the present invention. As described above, in step 1, the primary MC process of mixing and pulverizing mag carbon, a carbonation reaction accelerator and a Ca-based layered mineral is performed. By further administering and performing the secondary MC process, the self-healing admixture of the present invention is prepared as a novel reactive compound.

According to the contents described above, the self-healing admixture of the present invention not only consists of mag carbon, a carbonation reaction accelerator, a Ca-based layered mineral, and an organic acid additive, but also consists of two times through the first MC process, the powder recovery process and the second MC process. Since it is manufactured through the MC process, it has a multi-lamellar structure, and while maintaining the unique properties of each of the composition materials mixed as powder, interfacial bonding and mechanochemical bonding between the particles of the powder. , have very high activity.

Therefore, when a self-healing concrete composition is prepared using the self-healing admixture of the present invention and a concrete structure is manufactured using the self-healing admixture, the time for initial crack healing of the concrete structure and complete healing of the damaged concrete structure is reduced to less than 14 days. Excellent healing performance is expressed. That is, in the case of the conventional self-healing concrete composition, there was a limitation that it takes about 28 days to more than about 28 days to heal a crack of 0.3 mm level, but the self-healing concrete composition using the self-healing admixture according to the present invention is the Beyond the limit, only a crack healing time of about 14 days is required.

As such, the self-healing admixture of the present invention can greatly shorten the crack healing time of the self-healing concrete composition, and thus can play a large role in improving the stability and durability of large concrete structures that are difficult to maintain. do.

In addition, in the case of the self-healing admixture of the present invention, the deterioration of the physical performance of the existing binder is greatly reduced, and the deterioration of workability is also lowered. will do

Hereinafter, specific examples and comparative examples of the self-healing admixture of the present invention will be described.

(Common to Examples and Comparative Examples)

- A mortar composition was prepared by mixing an admixture, sand and cement.

- For fine aggregate, ISO standard yarn was used, and for cement, type 1 ordinary Portland cement (OPC) was used.

- 5 parts by weight of admixture was mixed with respect to 100 parts by weight of cement.

- W/B was set to 40%, and the mixing ratio of aggregates, that is, the ratio of B:S was set to 1:2. Here, W means water, S means fine aggregate, and B means binder excluding self-healing admixture, that is, cement.

- Fluidity (flow) was measured in accordance with KS L 5105 (Test method for compressive strength of hydraulic cement mortar).

- Compressive strength was measured at 7 and 28 days of age in accordance with KS L ISO 679 (strength test method of cement), respectively.

- In order to evaluate the self-healing performance of the mortar composition, a test specimen was prepared and a hydrostatic permeability test was performed to measure the change in the amount of runoff of the specimen, and the measurement result was expressed as self-healing performance (permeability reduction rate), and the test specimen that completed the hydrostatic permeability test By taking a picture of the micro-cracks, the state of the micro-cracks and the generation of the healing product were visually confirmed.

- The details of the hydrostatic water permeability test method for self-healing performance evaluation are as follows A) to F). 2 is a schematic diagram showing a series of processes for generating a crack in the form of a split in the test specimen and measuring the water permeation rate in a state where the crack width is controlled.

A) The specimen is manufactured in the form of a round cylinder (Ф100ㅧH200mm), cured at a temperature of 17-23 degrees Celsius and a humidity of 55-65% in a thermo-hygrostat for 24 hours, then demolded and submerged at a temperature of 18-22 degrees Celsius for 14 days. It was produced by curing.

B) The specimen, which was cured in water for 14 days, was cut to a thickness of 49 to 51 mm using a high-speed cutter, and then forced induced cracks were formed in the specimen using a cracking platen. Figure 3 is a drawing substitute photograph showing the cutting of the specimen.

C) A cracked specimen was induced to crack with a crack width of 0.25 to 0.35 mm by attaching 0.3T*15 mm silicone sheets to both sides of the specimen and fastening the specimen using clamps on the upper and lower sides of the specimen. 4 (a) and (b) are drawings instead of pictures sequentially showing the process of inducing a forced crack in the specimen, respectively.

D) The specimen, which has been fastened to the clamp, was mounted on a hydrostatic water permeability tester, and water was filled in the upper acrylic tube (water head 240-260 mm), and the amount of runoff falling to the lower part of the specimen was measured.

E) After starting the permeation test, the water dripping from the cracked part of the specimen was drained for 3 minutes, and then the amount of runoff permeated from the specimen was measured for 7 minutes, and the average value was set as the initial permeability. 5 is a picture substitute for a drawing showing a state of measuring the amount of runoff.

F) The specimen, whose initial water permeability was measured, was immersed in water for 14 days and cured to self-heal. At the time of 14 days, the amount of runoff was measured by the same experimental method as above to calculate the rate of permeation reduction.

(Specific contents of Comparative Example 1)

- In Comparative Example 1, a mortar composition was prepared by mixing only sand and cement without using a self-healing admixture.

(Specific contents of Comparative Example 2)

- In Comparative Example 2, a mortar composition was prepared by mixing a self-healing admixture, sand and cement.

- The self-healing admixture of Comparative Example 2 has a composition consisting of 70% by weight of Magcarbon (MgO-C), 15% by weight of Ca-based layered minerals, and 15% by weight of organic acid additives, and does not include a carbonation reaction accelerator.

(Specific contents of Comparative Example 3)

- In Comparative Example 3, a mortar composition was prepared by mixing a self-healing admixture, sand and cement.

- The self-healing admixture of Comparative Example 3 has a composition consisting of 60% by weight of Magcarbon (MgO-C), 20% by weight of a carbonation reaction accelerator, and 20% by weight of an organic acid additive, and does not contain Ca-based layered minerals.

(Specific contents of Comparative Example 4)

- In Comparative Example 4, a mortar composition was prepared by mixing a self-healing admixture, sand and cement.

- The self-healing admixture of Comparative Example 4 has a composition consisting of 65% by weight of Magcarbon (MgO-C), 20% by weight of a carbonation reaction accelerator, 15% by weight of Ca-based layered minerals, and 10% by weight of organic acid additives.

- However, in the case of Comparative Example 4, a self-healing admixture prepared to have a composition including Mag carbon, a carbonation reaction accelerator, a Ca-based layered mineral, and an organic acid additive is used. Otherwise, it is manufactured by simply mixing and pulverizing without performing the 1st or 2nd MC process.

(Specific contents of the embodiment)

- In the example, a mortar composition was prepared by mixing the self-healing admixture, fine aggregate (sand) and cement according to the present invention.

- The self-healing admixture of the embodiment has a composition consisting of 65% by weight of Magcarbon (MgO-C), 20% by weight of a carbonation reaction accelerator, 15% by weight of Ca-based layered minerals, and 10% by weight of organic acid additives.

- In particular, the self-healing admixture of the embodiment is manufactured through two MC processes through the manufacturing process of the present invention described above, that is, the primary MC process, the powder recovery process, and the secondary MC process of the present invention according to the above description. .

-At this time, the first MC process was carried out at a grinding speed of 180-190 rpm, and the second MC process was carried out at a grinding speed of 120-130 rpm.

In Table 1 and Table 2, the compositions of Comparative Examples 1, 2, 3 and Examples are summarized in detail, respectively.

In Table 1, W means water, S means fine aggregate, and B means binder excluding self-healing admixture, that is, cement.

As summarized in Tables 1 and 2, Comparative Example 1 does not use a self-healing admixture, and Comparative Examples 2 and 3 uses a self-healing admixture, but some of the components constituting the self-healing admixture of the present invention are omitted. In one form, a self-healing admixture manufactured through the MC process is used. Comparative Example 4 uses the self-healing admixture prepared without going through the MC process presented in the present invention, although it has the composition components and composition range according to the present invention, and the Example uses the self-healing admixture prepared according to the present invention. will be. Table 3 below summarizes the results of measuring flow, compressive strength, and 14-day permeability reduction for Comparative Examples 1 to 4 and Examples described above.

As summarized in Table 3 above, in the case of the example corresponding to the test specimen including the self-healing admixture according to the present invention, it can be confirmed that the 14-day permeability reduction rate is very excellent compared to Comparative Examples 1 to 4.

6 is a drawing substitute photograph showing a crack recovery image for the Example of Table 2 corresponding to the test body including the self-healing admixture according to the present invention. As can be seen in FIG. 6, in the case of the example of Table 2 corresponding to the test specimen including the self-healing admixture according to the present invention, the self-healing product is made while cracks with a crack width of 0.25 to 0.35 mm are smoothly restored and healed. became

As such, the self-healing admixture according to the present invention and the self-healing concrete composition prepared including the same not only exhibit an excellent crack healing effect, but also shorten the time for initial crack healing and complete healing of damaged parts to less than 14 days. It has the advantage of being able to express healing performance at an early stage.

As mentioned above, the present invention is derived as a result of a research project (task number 21SCIP-C159059-02) supported by the Ministry of Land, Infrastructure and Transport/Korea Agency for Transport Science and Technology (This work is supported by the Korea Agency for Infrastructure Technology) Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 21SCIP-C159059-02)).

Claims (6)

45 to 84% by weight of Mag carbon, 6 to 20% by weight of a carbonation reaction accelerator, 5 to 20% by weight of a Ca-based layered mineral, and 5 to 15% by weight of an organic acid additive;
A first MC process of grinding at a grinding speed of 150 to 200 rpm and grinding for 5 to 9 hours by mixing mag carbon, a carbonation reaction accelerator and a Ca-based layered mineral;
recovering powder by sieving the resultant of the first MC process; and
Self-healing, characterized in that it is prepared by a process comprising the step of mixing the organic acid additive in the recovered powder and performing a secondary MC process of grinding at a grinding speed of 120 to 150 rpm and grinding for 2 to 4 hours admixture. The method of claim 1,
Mag carbon 65% by weight;
10% by weight of a carbonation reaction accelerator;
Ca-based layered mineral 15% by weight; and
Self-healing admixture, characterized in that it has a composition consisting of 10% by weight of an organic acid additive. 45 to 84% by weight of Mag carbon, 6 to 20% by weight of a carbonation reaction accelerator, and 5 to 20% by weight of Ca-based layered minerals 1 Grinding at a grinding speed of 150 to 200 rpm and grinding for 5 to 9 hours Carrying out the MC process;
recovering powder by sieving the resultant of the first MC process;
Preparing a self-healing admixture including; mixing 5-15 wt% of an organic acid additive in the recovered powder and performing a secondary MC process of grinding at a grinding speed of 120-150 rpm and grinding for 2 to 4 hours A method of manufacturing a self-healing admixture, characterized in that it is done. 4. The method of claim 3,
In the step of performing the first MC process, 65% by weight of mag carbon, 10% by weight of a carbonation reaction accelerator, and 15% by weight of Ca-based layered minerals are mixed;
In the step of performing the second MC process, a method of manufacturing a self-healing admixture, characterized in that 10% by weight of an organic acid additive is mixed. A self-healing concrete composition comprising a self-healing admixture, aggregate and cement,
The self-healing admixture has a composition consisting of 45 to 84% by weight of Mag carbon, 6 to 20% by weight of a carbonation reaction accelerator, 5 to 20% by weight of a Ca-based layered mineral, and 5 to 15% by weight of an organic acid additive;
The self-healing admixture contains 45 to 84% by weight of Mag carbon, 6 to 20% by weight of a carbonation reaction accelerator, and 5 to 20% by weight of a Ca-based layered mineral, with a grinding speed of 150 to 200 rpm and grinding for 5 to 9 hours. performing a primary MC (mechanochemical) process of pulverizing under conditions;
recovering the powder by sieving the resultant of the first MC process;
Prepared by a manufacturing method comprising; mixing 5 to 15% by weight of an organic acid additive in the recovered powder and performing a secondary MC process of grinding under the conditions of grinding at a grinding speed of 120 to 150 rpm and grinding for 2 to 4 hours A self-healing concrete composition, characterized in that it has been 6. The method of claim 5,
The self-healing admixture has a composition consisting of 65% by weight of Mag carbon, 10% by weight of a carbonation reaction accelerator, 15% by weight of a Ca-based layered mineral, and 10% by weight of an organic acid additive,
In the process of manufacturing the self-healing admixture, in the step of performing the first MC process, 65% by weight of mag carbon, 10% by weight of a carbonation reaction accelerator, and 15% by weight of Ca-based layered minerals are mixed;
In the step of performing the second MC process, a self-healing concrete composition comprising 10 wt% of an organic acid additive.

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