KR20210101904A - Manufacturing equipment for cement paste - Google Patents

Abstract

The present invention relates to a device for preparing cement paste having improved strength and toughness by mixing nanofibers and a cement solution. A cement paste preparing device, according to an embodiment of the present invention, comprises: an electrospinning unit (110) generating nanofibers (10a) by spraying a polymer solution (10) supplied to a syringe (111) from the outside to a spraying means (111a); a stirring unit (120) preparing cement paste by stirring the nanofibers (10a) inserted from the electrospinning unit (110) and a cement solution (20) supplied from the outside with a stirring means; and a power supply unit (130) supplying power to the electrospinning unit (110) and the stirring unit (120), respectively, wherein the polymer solution (10) is a first polymer solution (11) in which a first formic acid (11a) and chloroform (11b) are mixed, or a second polymer solution (13) in which a second formic acid (13a) and dichloromethane (13b) are mixed.

Description

Cement paste manufacturing equipment {Manufacturing equipment for cement paste}

The present invention relates to an apparatus for manufacturing a cement paste, and more particularly, to an apparatus for manufacturing a cement paste having improved strength and toughness by mixing nanofibers and a cement solution.

Concrete, a composite material that plays an important role in the global architectural field, is governed by two main phases: the coarse aggregate and the matrix phase. Among these major steps, the matrix phase, in which cement is the main component, has a problem in that the strength of the composite material is weak, and many building material researchers have studied ways to increase the strength of cement.

The mechanical strength of cement paste varies depending on various factors such as curing conditions, hydration process, microstructure, etc. In particular, research results have been published that modifying the microstructure using different mixtures has a significant effect on improving the mechanical strength. have. In addition, the effect of carbon nanofibers has been proven through research results showing that the cement performance was improved by using a different mixture of carbon nanofibers.

Nylon 66 nanofibers, one of the carbon nanofibers, are used in various fields, such as improving enzyme performance, removing membrane contamination in microalgal filtration, and heat-stable separators for lithium-ion batteries.

These nylon 66 nanofibers have high elastic modulus compared to other materials, have a high impact absorption rate, and are cross-linked in the mixture to improve the strength of the mixture, and thus are used in various fields as a very useful material.

However, nylon 66 nanofibers have never been commercialized as a material to improve the properties of cement.

On the other hand, nylon 66 nanofibers are produced by electrospinning. Here, electrospinning is a technique to produce different kinds of nanofibers such as polymer, ceramic and hybrid nanofibers with promising properties such as rough surface, nano-sized diameter and high strength based on the electrostatic interaction principle.

The conventional electrospinning system is disclosed in Korean Patent Publication No. 10-1586733 (Title of the invention: Electrospinning device for manufacturing nanofibers), Republic of Korea Patent Publication No. 10-1382574 (Title: For manufacturing nanofibers including an insulating case) Electrospinning apparatus) and Republic of Korea Patent Publication No. 10-1479194 (title of the invention: electrospinning apparatus and method of manufacturing a nanofiber mat using the same) have been disclosed as such.

Referring to the prior art, in the conventional electrospinning system, a high voltage power supply, injection means (syringe and needle or Taylor cone), and a metal collector are main components.

And in the conventional electrospinning system, the nanofiber properties are changed by the electrospinning settings such as the distance between the Taylor cone and the metal collector, the applied voltage, and the feed rate of the syringe. In addition, the properties of the nanofibers are changed according to the effect of changes in the properties of the polymer solution supplied to the syringe.

However, the conventional electrospinning system has never been commercialized as a method for improving the mechanical strength of cement, and accordingly, the conventional electrospinning system has never been proposed as a method for facilitating the agitation of the nylon 66 nanofiber and the cement solution. .

Republic of Korea Patent Publication No. 10-1586733 Republic of Korea Patent Publication No. 10-1382574 Republic of Korea Patent Publication No. 10-1479194

The present invention has been devised to solve the above problems, and by mixing the nanofibers and cement solution produced from the first polymer solution in which formic acid and chloroform are mixed or the second polymer solution in which formic acid and dichloromethane are mixed, strength and An object of the present invention is to provide an apparatus for producing a cement paste having improved toughness.

And an object of the present invention is to provide an apparatus for preparing a cement paste by lyophilizing and pulverizing the nanofibers before mixing the nanofibers and the cement solution, and then mixing the pulverized nanofibers and the cement solution.

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art to which the present invention belongs from the description below. can be understood

As a technical means for achieving the above object, the cement paste manufacturing apparatus according to an embodiment of the present invention injects the polymer solution 10 supplied to the syringe 111 from the outside with the injection means 111a, Electrospinning unit 110 for generating a fiber (10a); a stirring unit 120 for preparing cement paste by stirring the nanofibers 10a input from the electrospinning unit 110 and the cement solution 20 supplied from the outside with a stirring means; and a power supply unit 130 for supplying power to the electrospinning unit 110 and the stirring unit 120, respectively, wherein the polymer solution 10 is a mixture of the first formic acid 11a and chloroform 11b. The first polymer solution 11 or the second polymer solution 13 in which formic acid 13a and dichloromethane 13b are mixed.

And the manufacturing apparatus 100 is positioned between the electrospinning unit 110 and the stirring unit 120 to freeze-drying the nanofibers 10a before the nanofibers 10a are introduced into the stirring unit 120 . Freeze-drying unit 140 for freeze-drying; and the freeze-drying unit 140 and the stirring unit 120 positioned between the freeze-dried nanofibers 10a by the freeze-drying means and pulverizing the pulverized nanofibers 10a with the stirring unit ( It further includes; a crushing unit 150 to be put into the 120).

In addition, the freeze-drying unit 140 includes a freeze-drying container 141 through which the spraying means 111a is penetrated at the upper part, the nanofibers 10a are put, and the lower part is combined with the pulverizing unit 150; Freezing means 142 connected to the freeze-drying container 141 and supplying cooling air to the freeze-drying container 141; a decompression means 143 connected to the freeze-drying container 141 and depressurizing the freeze-drying container 141; a heating means 144 connected to the freeze-drying container 141 and heating the freeze-drying container 141 decompressed by the decompression means 143; a water vapor collecting means 145 connected to the freeze-drying container 141 and collecting water vapor generated from the nanofibers 10a in an ice state by the decompression means 143 and the heating means 144; and a thawing unit 146 connected to the water vapor collecting unit 145 and spraying steam to the water vapor collecting unit 145 to thaw the ice collected by the water vapor collecting unit 145 .

And the nanofiber 10a may be nylon 66.

In addition, the nanofiber 10a is, when the polymer solution 10 is the first polymer solution 11, is sprayed from the spraying means 111a to produce the first nanofiber 12, and the first nanofiber 12 ), the surface is rough and cracked by chloroform (11b).

And the first nanofiber 12 is interspersed with the hydration product of cement when it is stirred with the cement solution 20 from the stirring unit 120, and cross-linked to the hydration product of cement through a rough and cracked surface.

In addition, in the first polymer solution 11 , the volume ratio of the first formic acid 11a and chloroform 11b is 4:1 for the rough and cracked surface of the first nanofiber 12 .

And the nanofiber 10a is, when the polymer solution 10 is the second polymer solution 13, is sprayed from the spraying means 111a to be produced as a second nanofiber 14, and the second nanofiber 14 , a microfilm is formed at the intersection between the nanofibers by dichloromethane (13b).

In addition, the second nanofibers 14 are interspersed with the hydration product of cement when agitated with the cement solution 20 from the agitator 120 , and are cross-linked to the hydration product of cement through a micro-membrane.

And in the second polymer solution 13, the volume ratio of the second formic acid 13a to the dichloromethane 13b is 4:1 for the formation of a fine film.

In addition, the stirring unit 120, the nanofiber (10a) and the cement solution (20) is put in the stirring vessel (121); A stirring bar 123 which is located inside the stirring vessel 121 and is a magnetic substance for stirring the nanofibers 10a and the cement solution 20 that are put into the stirring vessel 121; And supporting the lower portion of the stirring vessel 121, the magnet rotating body mounted on the motor is rotated by power supplied from the power supply unit 130, the magnet rotating body through the rotation and the opposite pole of the magnet rotating body It includes a; magnetic stirrer 125 to rotate the stir bar 123 along the.

According to an embodiment of the present invention, the strength and toughness of the cement paste may be improved by crosslinking the first nanofibers having a rough and cracked surface to the hydration product of cement based on the first polymer solution.

And, according to an embodiment of the present invention, the second nanofiber, on which a fine membrane is formed based on the second polymer solution, is cross-linked to the hydration product of cement, so that the strength and toughness of the cement paste can be improved.

In addition, according to an embodiment of the present invention, by freeze-drying and pulverizing the nanofibers, the mixing efficiency between the nanofibers and the cement solution can be maximized.

On the other hand, the effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be able

1 is a view for explaining a cement paste manufacturing apparatus according to an embodiment of the present invention.
2 is a view for explaining a polymer solution according to an embodiment of the present invention.
3 is a view for explaining an additional configuration of the cement paste manufacturing apparatus according to an embodiment of the present invention.
4 is a view showing a specimen for a tensile strength test and a compressive strength test.
5 is an image showing a specimen for an actual tensile strength test and a compressive strength test.
6 is an image showing the shape of the first and second nanofibers.
7 is an image showing the microstructure of the hardened cement paste including first and second nanofibers.
8 is a graph showing the TGA-DTG results of nanofibers.
9 to 11 are graphs showing TGA-DTG results of hardened cement paste.
12 is a graph comparing the TGA results of the normal cement paste and the hardened cement paste including first and second nanofibers.
13 is a graph showing the mechanical strength results after 28 days of a normal cement paste and a hardened cement paste including first and second nanofibers.
14 is a strain curve of a normal cement paste and a hardened cement paste including first and second nanofibers.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, since the description of the present invention is only an embodiment for structural or functional description, the right (the scope of the present invention) should not be construed as being limited by the embodiment described in the text. That is, the embodiment is subject to various changes Since this is possible and can have various forms, it should be understood that the scope of the present invention includes equivalents that can realize the technical idea.In addition, the object or effect presented in the present invention must be included in all of the specific embodiments or It is not meant to include only such effects, so the scope of the present invention should not be construed as being limited thereby.

The meaning of the terms described in the present invention should be understood as follows.

Terms such as “first” and “second” are for distinguishing one component from another, and the scope of rights should not be limited by these terms. For example, a first component may be termed a second component, and similarly, a second component may also be termed a first component. When a component is referred to as being “connected” to another component, it may be directly connected to the other component, but it should be understood that other components may exist in between. On the other hand, when it is mentioned that a certain element is "directly connected" to another element, it should be understood that the other element does not exist in the middle. Meanwhile, other expressions describing the relationship between elements, that is, “between” and “immediately between” or “neighboring to” and “directly adjacent to”, etc., should be interpreted similarly.

The singular expression is to be understood as including the plural expression unless the context clearly dictates otherwise, and terms such as "comprises" or "have" refer to the described feature, number, step, action, component, part or these It is intended to indicate that a combination exists, and it should be understood that it does not preclude the possibility of the existence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms defined in the dictionary should be interpreted as being consistent with the meaning of the context of the related art, and cannot be interpreted as having an ideal or excessively formal meaning unless explicitly defined in the present invention.

Hereinafter, the cement paste manufacturing apparatus 100 (hereinafter, referred to as "manufacturing apparatus 100") according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a cement paste manufacturing apparatus according to an embodiment of the present invention, Figure 2 is a view for explaining a polymer solution according to an embodiment of the present invention, Figure 3 is an embodiment of the present invention It is a view for explaining an additional configuration of the cement paste manufacturing apparatus according to the example.

1 to 3 , the manufacturing apparatus 100 includes an electrospinning unit 110 , a stirring unit 120 , and a power supply unit to prepare a cement paste in which the nanofibers 10a and the cement solution 20 are mixed. 130 , and is configured to include a freeze-drying unit 140 and a pulverizing unit 150 .

The electrospinning unit 110 is provided with a syringe 111 and a pump 113 for electrospinning the polymer solution 10 . Here, the electrospinning of the electrospinning unit 110 is made by the power supplied from the power supply unit (130).

The syringe 111 accommodates the polymer solution 10 supplied from the outside through the pump 113 , and an injection means 111a is provided at an end for electrospinning the polymer solution 10 . Here, the outside may be a polymer solution manufacturing apparatus (not shown) for manufacturing the polymer solution 10 .

The injection means (111a) allows the polymer solution 10 of the syringe 111 to be maintained in a droplet shape due to surface tension before power is supplied from the power supply unit 130, but when power is supplied from the power supply unit 130, the polymer solution 10 While the solution 10 takes the shape of a Taylor cone, it has an electrical repulsive force.

At this time, when the electrical repulsive force becomes greater than the surface tension, the polymer solution 10 is spun and stretched from the spraying means 111a, and the nanofibers 10a are generated through this process.

Here, the nanofiber 10a is a polyamide produced by polycondensation of hexamethylindiamine and adipic acid, and is widely used in medical and industrial fibers, plastic molded products, etc. It may be nylon 66, a material that is widely demanded for industrial materials such as industrial ropes.

And the injection means (111a) is provided with a plurality of injection means having different diameters of the nanofibers (10a) to generate the nanofibers (10a) of various diameters can be separated and combined from the syringe (111). As a specific example, the injection means 111a may be provided with a diameter of 20, 23, or 25 mm.

In addition, the injection means 111a may be spaced apart from the stirring vessel 121 of the stirring unit 120 by 60 mm.

Meanwhile, the polymer solution 10 may be divided into a first polymer solution 11 and a second polymer solution 13 .

The first polymer solution 11 is a polymer solution in which the first formic acid 11a and chloroform 11b are mixed. Specifically, the first polymer solution 11 is a formic acid 99% (HCOOH; CAS No. 64-18-6) of the first formic acid (11a) and chloroform (11b) (CHCl ₃ ; CAS No. 67-66-) It is a polymer solution mixed with 3).

The first polymer solution 11 is, for example, a volume ratio of the first formic acid 11a and chloroform 11b of 4:1, and is to be prepared by stirring at room temperature for 3 hours from a polymer solution manufacturing apparatus (not shown). can

And the first polymer solution 11 is also a solution for the first nanofibers 12 generated through the spraying means (111a). Here, the first nanofiber 12 may be a first nylon 66.

The first nanofibers 12 are generated based on the first polymer solution 11, and are interspersed in the hydration product of cement when stirred with the cement solution 20 through the stirring unit 120, but through a rough and cracked surface. Crosslinked to hydration products of cement.

The surface of the first nanofibers 12 is rough and cracked by chloroform 11b, and is cross-linked to the hydration product of cement.

Accordingly, it will be understood that the injection means 111a generates the first nanofibers 12 when the first polymer solution 11 is supplied to the syringe 110 .

The second polymer solution 13 is a polymer solution in which the second formic acid 13a and dichloromethane 13b are mixed. Specifically, the second polymer solution 13 is the same as the first formic acid 11a and the formic acid 99% (HCOOH; CAS No. 64-18-6) of the second formic acid 13a and dichloromethane 13b (CH2Cl2). ; CAS No 75-09-2) is a mixed polymer solution.

As such, the second polymer solution 13 has, for example, a volume ratio of the second formic acid 13a and dichloromethane 13b of 4:1, and is stirred from a polymer solution manufacturing device (not shown) at room temperature for 3 hours. can be manufactured.

In addition, the second polymer solution 13 is also a solution for the second nanofibers 14 generated through the spraying means (111a). Here, the second nanofiber 14 may be a second nylon 66 having a different solute from the first nanofiber 12 .

The second nanofibers 14 are generated based on the second polymer solution 13, and are interspersed in the cement hydration product when stirred with the cement solution 20 through the stirring unit 120, and hydration of the cement through the micro-membrane. crosslinked to the product.

The second nanofiber 14 is formed with a micro-membrane at the intersection between the nano-fibers by dichloromethane 13b, and is cross-linked to the hydration product of cement through the micro-membrane.

Accordingly, it will be understood that the injection means 111a generates the second nanofibers 14 when the second polymer solution 13 is supplied to the syringe 110 .

The pump 113 is connected to the polymer solution manufacturing device (not shown) and the syringe 111, respectively, so that the first polymer solution 11 or the second polymer solution 13 prepared from the polymer solution manufacturing device (not shown) is supplied with the syringe. (110) to be supplied.

The agitation unit 120 includes a stirring vessel 121, a stirring bar ( 123) and a magnetic stirrer 125 are provided.

Here, the outside may be a cement solution manufacturing apparatus (not shown) for manufacturing the cement solution 20, and the cement solution 20 is a portland cement in which raw materials containing lime, silica, alumina and iron oxide are mixed in an appropriate ratio. The solution may be included.

The stirring vessel 121 is a vessel into which the cement solution 20 and at least one of the first nanofibers 12 and the second nanofibers 14 generated from the spraying means 110 are put.

The stirring vessel 121 may be a metal vessel provided with an electrical insulating wall on one side, preferably on the inside.

The stirring bar 123 is located at the lower inner side of the stirring vessel 121, and at least one of the first nanofibers 12 and the second nanofibers 14 put into the stirring vessel 121 through rotation. Let the cement solution 20 be stirred.

The stirring bar 123 is rotated by the magnetic stirrer 125, and for this purpose, it is made of a magnetic material.

The magnetic stirrer 125 supports the lower portion of the stirring vessel 123 , and receives power from the power supply unit 130 for rotation of the stirring bar 123 .

And when power is supplied from the power supply unit 130 in the magnetic stirrer 125, a magnet rotating body (not shown) mounted on a motor (not shown) provided therein is rotated by power, and a magnet rotating body (not shown) At least one of the first nanofiber 12 and the second nanofiber 14 by causing the stirring bar 123 to rotate along a pole opposite to the pole of the magnet rotating body (not shown) through the rotation of the The nanofiber and the cement solution 20 are mixed by the stirring bar 123 .

That is, the stirring unit 120 is capable of stirring at least one of the first nanofiber 12 and the second nanofiber 14 and the cement solution 20 based on the rotation of the magnetic body through the configuration. It is possible to implement an E-Spinning process.

The power supply unit 130 has one side of the power supply circuit connected to the electrospinning unit 110 and the stirring unit 120, respectively, to supply power to the electrospinning unit 110 and the stirring unit 120, respectively.

Here, to supply power to the electrospinning unit 110 is to supply power to the injection means (111a), to supply power to the stirring unit 120 is to supply power to the magnetic stirrer 125.

In addition, the power supply unit 130 supplies power to the injection means 111a, for example, the injection means 111a generates the first nanofiber 12 or the second nanofiber 14 at a voltage of 12 kV. can be done for

The power supply unit 130 is preferably the other side of the circuit is grounded in order to prevent the supply of more than critical power to the injection means (111a) and the magnetic stirrer (125).

The freeze-drying unit 140 is the first nanofiber 12 or the second nanofiber 14 before the at least one nanofiber and the cement solution 20 are stirred, the first nanofiber 12 or the second nanofiber In order to freeze-dry the fibers 14, a freeze-drying container 141, a freezing means 142, a decompression means 143, a heating means 144, a water vapor collecting means 145 and a thawing means 146 are included. do.

In the freeze-drying container 141, the injection means 111a is penetrated in the upper part 141a for the input of the first nanofiber 12 or the second nanofiber 140.

The upper portion (141a) of the freeze-drying container is configured to be separated and combined from the freeze-drying container (141) for replacement of the stirring bar (123).

In addition, when the injection means (111a) is changed to change the diameter of the first nanofiber 12 or the second nanofiber 14, the upper portion 141a of the freeze-drying container is penetrated through the injection means 111a. A sphere (not shown) may be replaced with another formed upper part.

The freezing means 142 is connected to the freeze-drying container 141, and supplies cooling air to the freeze-drying container 141 to the first nanofiber 12 or the second nanofiber 14 of the freeze-drying container 141. to be frozen. Here, the cooling air may be air for freezing, such as liquid nitrogen.

The decompression means 143 is connected to the freeze-drying container 141, and by allowing the freeze-drying container 141 to be in a vacuum state, the freeze-drying container 141 is decompressed.

As such, the decompression means 143 depressurizes the freeze-drying container 141 so that water vapor is generated from the first nanofiber 12 or the second nanofiber 14 frozen by the water vapor collecting means 145 . to form conditions.

The heating means 144 is connected to the freeze-drying container 141 and heats the freeze-drying container 141 decompressed by the decompression means 143 .

Here, the heating means 144 supplies heating air for heating the freeze-drying container 141 to the freeze-drying container 141 .

In addition, the heating means 144 supplies heating air through a supply path different from the cooling air supply path of the freezing unit 142 . Accordingly, the freeze-drying container 141 may preferably be provided with a cooling air supply path and a heating air supply path separately.

As a specific example, the freezing means 142 is connected to the side of the freeze-drying container 141 so that the cooling air is diffused from the side of the freeze-drying container 141 , and the heating means 144 is the freeze-drying container 141 . It may be connected to the lower portion so that heated air is diffused from the lower portion of the freeze-drying container 141 .

The water vapor collecting means 145 is connected to the freeze-drying container 141 and collects water vapor generated from the first nanofiber 12 or the second nanofiber 14 by the decompression means 143 and the heating means 144 . collect

The water vapor collection means 145 collects water vapor by placing a temperature difference with the freeze-drying container 141 under reduced pressure and heated so that a pressure difference with the freeze-drying container 141 is generated, and by placing the temperature difference as described above, the water vapor becomes ice make it state

The thawing means 146 is connected to the water vapor collecting means 145 and sprays steam to the water vapor collecting means 145 to thaw the ice collected by the water vapor collecting means 141 .

The thawing means 146 sprays steam to the water vapor collecting means 145 to prevent the ice from being excessively collected in the water vapor collecting means 145 .

In addition, the thawing means 146 is operated whenever the freeze-drying process of the first nanofiber 12 or the second nanofiber 14 is completed to spray steam to the water vapor collecting means 145 .

The crushing unit 150 is combined with the lower portion 141b of the freeze-drying container, and the lyophilized first nanofiber 12 or the first lyophilized nanofiber 12 or second inputted through a through-hole (not shown) formed in the lower portion 141b of the freeze-drying container. 2 A grinding means for grinding the nanofibers 14 is provided.

If the pulverizing unit 150 is a means capable of pulverizing the lyophilized first nanofiber 12 or the second nanofiber 14, the type and method of pulverizing means is not limited.

In addition, the pulverization unit 150 is agitating the first nanofiber 12 or the second nanofiber 14 when the pulverization of the first nanofiber 12 or the second nanofiber 14 is completed, the first nanofiber 12 or the second nanofiber 14 is located on the lower side. It is put into the container (121).

Through this, the agitator 120 stirs the cement solution 20 with at least one of the lyophilized and pulverized first nanofibers 12 and second nanofibers 14 to prepare a cement paste. .

On the other hand, the manufacturing apparatus 100 can manufacture the cement paste because the electrospinning and stirring process is performed even if the configuration of the freeze-drying unit 140 and the crushing unit 150 are omitted.

Hereinafter, an embodiment of an experiment for analyzing the hardened cement paste including the first nanofibers 12 and the hardened cement paste including the second nanofibers 14 will be described in detail.

In Example 1, for the tensile strength and compressive strength tests, 4.3 ml of the first polymer solution 11, which is 5 wt % of 100 g of the cement solution 20, was used as a cement powder containing the first nanofibers 12. was prepared, and a cement paste having a constant 0.5 w/c ratio (weight ratio of water/cement) was prepared using the above cement powder.

After that or at the same time, 4.3 ml of the second polymer solution 13, which is 5 wt % of 100 g of the cement solution 20, was used to prepare a cement powder containing the second nanofibers 14, and the cement powder was used to prepare a cement paste with a constant 0.5 w/c ratio (weight ratio of water/cement).

Thereafter, specimens for tensile strength and compressive strength tests were prepared using briquettes and cubic oil molds.

Here, the briquette specimens may be also been made of a form as shown in 4 (a), the size of length 75 mm, 25 mm, a minimum cross-section thickness of 645 mm ^2.

These briquette specimens were prepared three at a time as shown in Fig. 5 (a). Here, the three briquette specimens on the left shown in (a) of FIG. 5 may be specimens of general cement paste, and the three briquette specimens in the center may be specimens of cement paste based on the first nanofiber 12, and the right The three briquette specimens may be specimens of cement paste based on the second nanofiber 14 .

On the other hand, the cubic oil mold specimen was prepared in the form as shown in (b) of FIG. 4, and may be a cube of ^{50×50×50 mm 3 .}

As shown in FIG. 5(b), three cube oil mold specimens were prepared. Here, the three cube oil mold specimens on the left shown in (b) of FIG. 5 may be specimens of general cement paste, and the three cube oil mold specimens in the center are specimens of cement paste based on the first nanofiber 12. Also, the three cube oil mold specimens on the right may be specimens of cement paste based on the second nanofiber 14 .

The above-mentioned briquette specimen and cubic oil mold specimen were used in the tensile strength and compressive strength tests of SEM after curing for 28 days.

In Example 2, in order to analyze the shape of the first nanofiber 12 and the second nanofiber 14, SEM obtained by performing SEM analysis on the fractured portion of the briquette specimen among the specimens of Example 1 The image is as shown in FIG. 6 .

Here, Fig. 6 (a) is the form of the first nanofiber 12 having a magnification of 10 k, Fig. 6 (b) is the form of the first nanofiber 12 having a magnification of 50 k, ( c) is an image of the shape of the second nanofiber 14 having a magnification of 10 k, and FIG. 6 (d) is an image of the shape of the second nanofiber 14 having a magnification of 50 k.

Referring to (a) and (b) of Figure 6, the first and second nanofibers 12 and 14 are in contact between a plurality of nanofibers to form a net shape, and have a continuous uniform diameter along the length. will achieve In addition, the first nanofiber 12 has a relatively rough and cracked surface compared to the second nanofiber 14 .

Referring to (c) and (d) of Figure 6, the second nanofiber 14 has a flat surface compared to the first nanofiber 12, and unlike the first nanofiber 12, at the intersection between the nanofibers. A fine film is formed.

Through Example 2, the surface of the first nanofiber 12 is rough and cracked by the solvent chloroform 11b, and the second nanofiber 14 is the intersection point between the nanofibers by the solvent dichloromethane 13b. The result was derived that a fine film was formed on the

In Example 3, to analyze the fracture surface of the tensile strength test on the cured specimen including the first nanofiber 12 and the cured specimen including the second nanofiber 14, SEM of the cured specimen The SEM image of the specimen cured by performing the analysis is as shown in FIG. 7 . In this case, the hardened specimen may refer to a hardened cement paste.

Here, (a) of FIG. 7 is a microstructure of a cured specimen including a first nanofiber 12 having a magnification of 10 k, and (b) of FIG. 7 is a first nanofiber 12 having a magnification of 50 k. The microstructure of the cured specimen including It is an image of the microstructure of the cured specimen including the second nanofiber 14 having

Referring to FIG. 7 , it was confirmed that the first and second nanofibers 12 and 14 were interspersed in the cement hydration product such as large prismatic crystals of the hydroxide product (CH) and small fibrous crystals of calcium silicate hydrate (CSH).

Referring to (a) and (c) of Figure 7, it was confirmed that the first and second nanofibers (12, 14) (“yellow arrows” in Figure 7) were connected to the cement hydration product to serve as a crosslinking agent. In addition, fractured nanofibers (“black arrows” in FIG. 7 ) were identified by the tensile strength test.

Referring to (b) of FIG. 7 , it was confirmed that the surface of the first nanofiber 12 inside the cured specimen was relatively rough and cracked compared to the second nanofiber 14 .

Referring to (d) of Figure 7, the second nanofiber 14 inside the cured specimen has a relatively flat surface compared to the first nanofiber 12, and unlike the first nanofiber 12, nanofibers It was confirmed that a fine film was formed at the intersection of the liver.

Through Example 3 above, the first nanofibers 12 were fixed to the cement matrix by a rough and cracked surface to connect the cement hydration product, and the second nanofibers 14 were fixed to the cement matrix through a micro-membrane to hydrate the cement. The result of linking the products was derived.

In Example 4, first, a TGA-DTG test of the nanofiber 10a was performed, and the results for the TGA-DTG test were measured as shown in FIG. 8 .

Here, Figure 8 is a graph showing the TGA-DTG test results of the nanofiber (10a).

Referring to FIG. 8 , a weight loss curve and a derivative thereof for the nanofiber 10a were confirmed, and through this, it was confirmed that about 90% of the weight loss of the nanofiber 10a occurred at 300° C. to 410° C., such a weight loss It was confirmed by the decomposition of the silver nanofibers (10a).

And the TGA-DTG test of the hardened cement including the first nanofiber 12 and the second nanofiber 14 was performed, and the TGA-DTG test results are as shown in FIGS. 9 to 11 .

Here, FIG. 9 is a graph showing the TGA-DTG result of the general cement (Portland cement) paste, and FIG. 10 is a graph showing the TGA-DTG result of the hardened cement paste including the first nanofiber 12, 11 is a graph showing the TGA-DTG results of the hardened cement paste including the second nanofibers 14 .

Referring to FIG. 9 , in a general cement paste with a w/c ratio of 0.5, the weight loss before 145° C. is caused by water, and the weight loss at 145° C. to 200° C. is achieved by dehydration of calcium silicate hydrate (CSH). It was confirmed that the weight loss at 400 ℃ ~ 500 ℃ is made by dehydration of calcium hydroxide (CH), and the weight loss at 550 ℃ ~ 900 ℃ is made by the decomposition of _{calcite (CaCO 3 ) due to the decarburization process.} .

10 to 11, peaks for the first and second nanofibers 12 and 14 were confirmed in the temperature range of 300 ℃ to 400 ℃, the ratio of the first and second nanofibers 12 and 14 In order to determine it, it was confirmed through TGA result comparison that it needed to be modified to have an initial weight of 300 °C.

In addition, the TGA results of the hardened cement paste including the first and second nanofibers 12 and 14 and the general cement paste were compared as shown in FIG. 12 .

Here, FIG. 12 (a) is a graph comparing the TGA results of the cement paste containing the first nanofiber and the general cement paste, and FIG. 12 (b) is the TGA result of the cement paste containing the second nanofiber and the general cement paste. This is a comparison graph. In FIG. 12 , plain paste is a general cement paste, N6601 MCP is a hardened cement including the first nanofibers 12 , and N6602 MCP is a hardened cement including the second nanofibers 14 .

Referring to (a) of FIG. 12 , it was confirmed that the TGA curve of the hardened cement paste including the first nanofiber 12 and the TGA curve of the general cement paste were different, especially at 410 ° C. was confirmed to be In addition, when the first nanofibers 12 were added to the hardened cement paste through the TGA curve shown in (a) of FIG. 12 , the ratio of the first nanofibers 12 at 410° C. was 0.62 (0.6) % was confirmed to be

Referring to (b) of FIG. 12 , it was confirmed that the TGA curve of the hardened cement paste including the second nanofiber 14 and the TGA curve of the general cement paste were different, especially at 410 ° C. was confirmed to be And when the second nanofiber 14 is added to the hardened cement paste through the TGA curve shown in (b) of FIG. 12, the ratio of the second nanofiber 14 at 410° C. is 0.79 (0.8)% was confirmed to be

Through the above fourth embodiment, the percentage of the first and second nanofibers 12 and 14 was derived that it can be estimated based on the weight loss between the TGA curves at a specific temperature (eg, 410° C.).

In Example 5, the mechanical properties of the ordinary cement paste after curing for 28 days, the cement paste including the first nanofibers 12 and the cement paste including the second nanofibers 14 were measured as shown in FIG. 13 . became

Here, FIG. 13 (a) is a graph showing the tensile strength result after 28 days, and FIG. 13 (b) is a graph showing the compressive strength result after 28 days. In FIG. 13 , plain paste is a general cement paste, N6601 MCP is hardened cement including the first nanofibers 12 , and N6602 MCP is hardened cement including second nanofibers 14 .

13 (a), the tensile strength of the general cement paste is 1.14 (0.172) Mpa, the tensile strength of the cement paste including the first nanofiber 12 is 1.46 (0.348) Mpa, the second nanofiber ( The tensile strength of the cement paste containing 14) was measured to be 1.51 (0.166) Mpa.

13 (b), the compressive strength of the general cement paste is 35.17 (0.725) Mpa, the compressive strength of the cement paste including the first nanofiber 12 is 37.90 (2.376) Mpa, the second nanofiber ( The tensile strength of the cement paste containing 14) was measured to be 36.58 (1.964) Mpa.

After the above tensile strength and compressive strength tests, the elastic modulus, deformability and toughness of the general cement paste, the hardened cement paste comprising the first nanofibers 12, and the hardened cement paste comprising the second nanofibers 14 was measured, and the toughness was measured through comparison of the strain curves of FIG. 14 .

Here, FIG. 14 is a strain curve of the hardened cement paste including the general cement paste and the first and second nanofibers 12 and 14 .

Referring to FIG. 14 , the toughness of the general cement paste is 62,000 J/m ³ , and the toughness of the hardened cement paste including the first nanofibers 12 is 92,000 J/m ^{3 , including} the second nanofibers 14 . The toughness of the hardened cement paste was measured to be ^{88,000 J/m 3 .}

Accordingly, compared to the toughness of ordinary cement paste, when the first nanofibers 12 are added to the cement solution 20 or cement material, the toughness of the hardened cement paste is 49%, and the second nanofibers 14 are cemented to It was confirmed that the toughness of the hardened cement paste was increased by 42% when added to the solution 20 or cement material.

In addition, the deformability of the hardened cement paste including the first nanofibers 12 was 26% compared to that of the general cement paste, and the deformability of the hardened cement paste including the second nanofibers 14 was lower than that of the ordinary cement paste. It was confirmed that it was increased by 22% compared to .

Through the above Examples 4 and 5, it was confirmed that the tensile strength, compressive strength and toughness of the cement paste hardened by the addition of the first and second nanofibers 12 and 14 were increased compared to the general cement paste.

However, it is confirmed that the hardened cement paste containing the second nanofiber 14 of 0.79% has higher tensile strength than the hardened cement paste containing the first nanofiber 12 of 0.62%, but the compressive strength is low. did.

Accordingly, it was confirmed that the increase in tensile strength depends on the ratio of the nanofiber content, but the compressive strength and toughness are not significantly affected by the ratio of the nanofiber content.

Furthermore, the tensile strength and toughness of the hardened cement paste comprising the first and second nanofibers 12 and 14 were determined with the first nanofiber 12 having a rough and cracked surface, as confirmed in Example 3 above. The result was derived that increased by the second nanofiber 14 that forms a fine film at the intersection of the nanofibers.

The detailed description of the preferred embodiments of the present invention disclosed as described above is provided to enable any person skilled in the art to make and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope of the present invention. For example, a person skilled in the art may use each configuration described in the above-described embodiments in a way that is combined with each other. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention. Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention. The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, claims that are not explicitly cited in the claims may be combined to form an embodiment, or may be included as new claims by amendment after filing.

10: polymer solution;
10a: nanofiber,
11: first polymer solution,
11a: first formic acid,
11b: chloroform;
12: first nanofiber,
13: second polymer solution,
13a: second formic acid,
13b: dichloromethane,
14: second nanofiber,
20: cement solution;
100: cement paste manufacturing apparatus,
110: electrospinning unit,
111: syringe,
111a: injection means,
113: pump,
120: agitation unit;
121: stirring vessel,
123: stir bar,
125: magnetic stirrer,
130: power supply,
140: freeze-drying unit,
141: freeze-drying vessel,
141a: the top of the freeze-drying vessel,
141b: the lower part of the freeze-drying container;
142: freezing means;
143: pressure reducing means;
144: heating means;
145: means for collecting water vapor;
146: means of thawing,
150: crushing unit.

Claims (11)

In the manufacturing apparatus 100 for manufacturing a cement paste mixed with nanofibers (10a),
an electrospinning unit 110 for generating the nanofibers 10a by spraying the polymer solution 10 supplied to the syringe 111 from the outside to the spraying means 111a;
a stirring unit 120 for preparing cement paste by stirring the nanofibers 10a input from the electrospinning unit 110 and the cement solution 20 supplied from the outside with a stirring means; and
and a power supply unit 130 for supplying power to the electrospinning unit 110 and the stirring unit 120, respectively.
The polymer solution 10,
Cement characterized in that it is a first polymer solution (11) in which first formic acid (11a) and chloroform (11b) are mixed or a second polymer solution (13) in which second formic acid (13a) and dichloromethane (13b) are mixed. paste making device. The method of claim 1,
The manufacturing apparatus 100,
It is positioned between the electrospinning unit 110 and the stirring unit 120 and freeze-dried the nanofibers 10a by freeze-drying means before the nanofibers 10a are introduced into the stirring unit 120 . freeze-drying unit 140; and
It is located between the freeze-drying unit 140 and the stirring unit 120 and the freeze-dried nanofibers 10a are pulverized by the freeze-drying means, and then the pulverized nanofibers 10a are pulverized. Cement paste manufacturing apparatus, characterized in that it further comprises a; crushing unit 150 for input to the stirring unit (120). 3. The method of claim 2,
The freeze-drying unit 140,
a freeze-drying container 141 through which the spraying means 111a is penetrated in the upper portion, the nanofiber 10a is put, and the lower portion is combined with the pulverizing unit 150;
a freezing means 142 connected to the freeze drying container 141 and supplying cooling air to the freeze drying container 141;
a decompression means 143 connected to the freeze-drying container 141 and depressurizing the freeze-drying container 141;
a heating means 144 connected to the freeze-drying container 141 and heating the freeze-drying container 141 decompressed by the decompression means 143;
a water vapor collecting means 145 connected to the freeze-drying container 141 and collecting water vapor generated from the nanofiber 10a in an ice state by the decompression means 143 and the heating means 144; and
and a thawing means (146) connected to the water vapor collecting means (145) and spraying steam to the water vapor collecting means (145) to thaw the ice collected by the water vapor collecting means (145). Cement paste manufacturing equipment. The method of claim 1,
The nanofiber (10a), cement paste manufacturing apparatus, characterized in that nylon 66. 5. The method of claim 4,
The nanofiber (10a) is,
When the polymer solution 10 is the first polymer solution 11, it is sprayed from the spraying means 111a to produce a first nanofiber 12,
The first nanofiber 12 is,
Cement paste manufacturing apparatus, characterized in that the surface is rough and cracked by the chloroform (11b). 6. The method of claim 5,
The first nanofiber 12 is,
Cement paste manufacturing apparatus, characterized in that when it is stirred with the cement solution (20) from the stirring unit (120), it is interspersed with the hydration product of cement, and cross-linked to the hydration product of the cement through the rough and cracked surface. 6. The method of claim 5,
The first polymer solution 11,
Cement paste manufacturing apparatus, characterized in that the volume ratio of the first formic acid (11a) and the chloroform (11b) is 4:1 for the rough and cracked surface of the first nanofiber (12). 5. The method of claim 4,
The nanofiber (10a) is,
When the polymer solution 10 is the second polymer solution 13, it is sprayed from the spraying means 111a to produce a second nanofiber 14,
The second nanofiber 14 is,
Cement paste manufacturing apparatus, characterized in that a fine film is formed at the intersection between the nanofibers by the dichloromethane (13b). 9. The method of claim 8,
The second nanofiber 14 is,
Cement paste manufacturing apparatus, characterized in that when it is stirred with the cement solution (20) from the stirring unit (120), it is interspersed with the hydration product of cement, and cross-linked to the hydration product of the cement through the fine membrane. 9. The method of claim 8,
The second polymer solution 13,
Cement paste manufacturing apparatus, characterized in that the volume ratio of the second formic acid (13a) and the dichloromethane (13b) to form the fine film is 4:1. The method of claim 1,
The stirring unit 120,
a stirring vessel 121 into which the nanofibers 10a and the cement solution 20 are put;
a stirring bar 123 which is located inside the stirring vessel 121 and is a magnetic substance for stirring the nanofibers 10a and the cement solution 20 that are put into the stirring vessel 121; and
Supporting the lower portion of the stirring vessel 121, the magnet rotating body mounted on the motor is rotated by the power supplied from the power supply unit 130, the magnet rotating body through the rotation and the pole of the magnet rotating body Cement paste manufacturing apparatus comprising a; magnetic stirrer (125) for rotating the stirring bar (123) along opposite poles.

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