KR20140019643A - Cement paste containing 2-dimension-graphite-oxide and manufacture method thereof - Google Patents

Abstract

The present invention relates to cement paste containing 2D graphite oxide with thickness of atomic unit and plane diameter of several tens of micrometer size and a manufacturing method thereof. The present invention provides 2D graphite oxide and cement paste mixed with cement and water. Moreover, the invention also provides a method for manufacturing cement paste, wherein the method includes a step (a) of manufacturing liquid phase slurry containing 2D graphite oxide and a step (b) of mixing the liquid phase slurry, cement, and water. [Reference numerals] (AA) Section; (BB) Nano material; (CC) Macro material; (DD) Zero-dimensional material; (EE) Cement powder; (FF) Admixture powder; (GG) One-dimensional material; (HH) Carbon nanotube; (II) Nano wire; (JJ) Nano fiber; (KK) Reinforced steel; (LL) Fiber; (MM) Two-dimensional material; (NN) Graphite oxide; (OO) Three-dimensional material; (PP) Sand; (QQ) Gravel

Description

Cement paste containing two-dimensional graphite oxide and its manufacturing method {Cement Paste containing 2-dimension-graphite-oxide and Manufacture method

The present invention relates to a cement paste to which two-dimensional graphite oxide (2-dimension-graphite-oxide) having a thin thickness in atomic units and a plane diameter of several tens of micrometers is added, and a method of manufacturing the same.

Cement broadly means a substance that bonds a substance to a substance, but generally refers to an inorganic binder hardener for civil engineering or construction. Among them, what is commonly referred to as cement today is Portland cement. The main components of Portland cement are lime (CaO), silica (SiO ₂ ), alumina (Al ₂ O ₃ ), iron oxide (Fe ₂ O), and the like. This cement is made of powder by sufficiently mixing the raw materials containing these in an appropriate ratio, adding an appropriate amount of gypsum to a clinker in which a part is melted and baked. Cement is the main construction material used for secondary products with concrete or cement as the main raw material.

Cement paste is made by mixing water and additives added as needed. The cement paste is a mortar composition in which the fine aggregate (sand) is added to the cement paste, and the coarse aggregate (gravel) is further included in the mortar. However, cement paste itself is also widely used for ground improvement (grouting).

Cement paste, mortar and concrete are hardened by the hydration reaction of cement, and the strengthening effect of three-dimensional particles such as sand and gravel causes mortar than cement paste and concrete to have stronger compressive strength than mortar. It can be called dimensional reinforcement effect.

On the other hand, as a binder of cement paste, mortar, and concrete, a mixture of blast furnace slag, fly ash, etc. can be used to further strengthen the compressive strength. This is called the 0-dimensional reinforcing effect because the effect of the mechanism to tightly fill the micro voids inside the concrete.

In addition, the cement paste, mortar and concrete composition may be reinforced by incorporating glass fiber, steel fiber, carbon fiber, plastic fiber, etc., tensile strength can be strengthened, it can be referred to as a one-dimensional reinforcement effect because the fiber is linear. In addition, reinforcing the tensile strength of concrete by reinforcing bar can also be called a one-dimensional reinforcing effect.

However, conventional two-dimensional reinforcing techniques for cement paste, mortar and concrete are not known.

The present invention is to provide a cement paste, mortar and concrete expressing a new functionality using a plate-shaped two-dimensional nanomaterial that has not been used previously.

The present invention provides a "cement paste in which two-dimensional graphite oxide, cement, and water are mixed" to solve the above problems.

In addition, the present invention "(a) preparing a liquid slurry containing a two-dimensional graphite oxide; And (b) mixing the liquid slurry, cement and water; Cement paste manufacturing method comprising a '' together.

After the step (a), "(a-1) heating the liquid slurry to lower the water content ''," (a-2) the alkali metal, the hydroxy compound of the alkali metal, the halide of the alkaline earth metal in the liquid slurry. Removing some of the surface hydrophilic groups of the two-dimensional graphite oxide by administering at least one of a compound, a hydroxy compound of an alkaline earth metal, an amine compound, and a strong base compound, '' (a-3) by irradiating ultraviolet light to the liquid slurry. Removing a portion of the surface hydrophilic group of the two-dimensional graphite oxide ", (a-4) by lowering the water content by administering the two-dimensional graphite oxide adsorbent to the liquid slurry" may optionally be additionally carried out. Two or more of steps (a-1) to (a-4) may be performed in parallel.

The cement paste including the two-dimensional graphite oxide according to the present invention is improved in the compressive strength, tensile strength, bending strength during curing and can be expected heat dissipation performance, electromagnetic shielding performance, photocatalyst function, radiation shielding function. The high functional cement paste can be mixed with sand to produce a high functional mortar, and further mixed with sand to produce high functional concrete can be used in a variety of construction, civil engineering.

1 is a table summarizing the technical significance of the graphite oxide applied to the present invention.
Figure 2 is a photograph of the liquid slurry containing a two-dimensional graphite oxide applied to the present invention.
3 is a graph showing a change in compressive strength of concrete according to the content of the two-dimensional graphite oxide.

The present invention provides a "cement paste in which two-dimensional graphite oxide, cement and water are mixed". The present invention relates to a cement paste, but it is obvious that the present invention can be extended to mortar or coarse concrete mixed with fine aggregate in cement paste. The present invention may be referred to as a two-dimensional reinforcement technology for cement paste, mortar and concrete, and two-dimensional graphite oxide is a core material for two-dimensional reinforcement (see FIG. 1).

In general, graphite material is easily peeled off by a weak van der Waals force (eg, pencil lead) between layers, resulting in a decrease in strength when entering cement paste, mortar, or concrete. However, carbon nanotubes, which are allotropes of graphite, are high-strength one-dimensional nanomaterials that do not have peeling between layers, unlike graphite powder, and when the materials are evenly dispersed in cement paste, mortar, and concrete, the tensile strength of the cured body is improved. However, evenly dispersing the carbon nanotubes in the concrete composition itself is not easy, and when the carbon nanotubes are introduced into the human body through the skin or the respiratory pathway, they are not embedded in the human tissue and are not discharged out. It is dangerous to be used in a large amount as a building and civil engineering material in that it is expensive.

The two-dimensional graphite oxide applied to the present invention can be obtained in a large amount through low-cost raw materials and processes, and because it is a plate-like material does not entangle or dry with each other, there is no danger to human body and good dispersion, so it is applied as a new building additive material. Advantageous conditions are provided below.

Graphite as a raw material for producing the two-dimensional graphite oxide is natural graphite, plate graphite, earth graphite, artificial graphite, nano graphite powder, intercalated graphite species (eg, graphite species intercalated sulfuric acid or phosphoric acid), expanded graphite, It is possible if the layer can be peeled off through chemical oxidation such as waste graphite (waste cells, waste battery graphite species).

As a method of obtaining graphite oxide from graphite, a Hummers method, a modified Hummers method, a Steudenmair method, a Hofman method, and a Hamdi method may be used. Can be. In addition, the core oxidizing agent for oxidizing graphite can be exemplified by a mixture of concentrated sulfuric acid, sodium nitrate and potassium permanganate and a mixture of jinhwan sulfuric acid, concentrated nitric acid and potassium chlorate. As other oxidizing agents, HNO ₃ , H ₂ SO ₄ , H ₄ P ₂ O ₇ , H ₃ AsO ₄ , HF, H ₂ SeO ₄ , HClO ₄ , CF ₃ COOH, BF ₃ (CH ₃ COOH) ₂ , HSO ₃ F, H ₅ IO ₆ , KMn0 ₄ , NaNO ₃ , KClO ₃ , NH ₄ CLO ₃ , AgClO ₃ , HClO ₃ , NaCl ₄ , NH ₄ ClO ₄ , CrO ₃ , (NH ₄ ) ₂ S ₂ O ₈ , PbO ₂ , MnO ₂ , As ₂ O ₅ , Na ₂ O ₂ , H ₂ O ₂ , N ₂ O ₅ , Mn ^{3 +} , Mn ^{4 +} , MnO ₂ , KMnO ₄ , HNO ₃ , HNO ₄ , CrO ₃ , Acetic Acid, Formic Acid, Chloric Acid, HI, HCL, HBr You can apply a mixture of two or more selected. As the composition of the specific oxidizing agent _{3KMNO 4 / H 2 SO 4 /0.5NaNO} 3 (or HNO 3), 6KMO 4 / H 2 SO 4 /0.5NaNO 3 (or HNO 3), 6KMnO 4/9: 1H 2 SO 4 -H ₃ PO ₄ and the like, and the oxidant combination is not limited to this composition.

The two-dimensional graphite oxide prepared by the above method has an atomic layer of 1 to 10 layers, the surface diameter of the plate is proportional to the size of the graphite particles used as a raw material and has a size of 1 to 100 micrometers.

Hereinafter, an example of a process of manufacturing the two-dimensional graphite oxide used in the present invention will be described. 100 g of graphite and 400 g of NaNO ₃ were added to an 18 L H ₂ SO ₄ solution, and ₁ K g of KMnO ₄ was slowly added over 1 hour while cooling. Thereafter, 50 L of _4-7 % H ₂ SO ₄ was slowly added over 1 hour to prepare a mixed solution containing H ₂ O ₂ . The precipitate is then washed with 3% H ₂ SO ₄ /0.5%H ₂ O ₂ or again with water. After filtering the hydrates that do not precipitate in the mixed solution, graphite ultra-fine debris impurities, centrifugation at 3,000 ~ 5,000RPM to increase the solid content was obtained only precipitate. The ultra-fine graphite waste impurities cause a decrease in strength properties of cement paste, mortar and concrete. Through this process it is possible to finally obtain a liquid slurry containing 0.1 ~ 20wt% two-dimensional graphite oxide. These liquid slurries have a lot of water content but are finely dispersed in water, and the two-dimensional graphite oxide is uniformly dispersed in water (see FIG. 2). Therefore, it is difficult to mix cement directly into the liquid slurry in this state, and it is necessary to add water to mix. As a result, when the content of the two-dimensional graphite oxide in the cement paste is within the range of 10 parts by weight relative to 100 parts by weight of the water (total of the liquid slurry and the added water), the mixing operation of the liquid slurry, cement and water can be easily performed. And the fluidity of the cement paste can be maintained at an appropriate level.

Cement paste manufacturing method as described above (a) preparing a liquid slurry containing a two-dimensional graphite oxide; And (b) mixing the liquid slurry, cement and water; I can arrange it. Powdered two-dimensional graphite oxide can be directly mixed with cement and water, but in this case, it does not appear to contribute significantly to the improvement of compressive strength of the hardened cement paste (see FIG. 3, and "graphite oxide solid content" of FIG. Weight ratio of two-dimensional graphite oxide to 100 parts by weight). This may be because the two-dimensional graphite oxide powder is not evenly dispersed between the cement powder when the two-dimensional graphite oxide, cement and water are directly mixed. Therefore, in the present invention, first, a liquid slurry containing two-dimensional graphite oxide is prepared, and then the liquid slurry and the cement and water are mixed to uniformly disperse the two-dimensional graphite oxide powder in the cement paste.

However, liquid slurry containing two-dimensional graphite oxide has a high viscosity, making it difficult to mix in a state where cement and water are mixed. Therefore, a method for facilitating the mixing operation of the liquid slurry and cement and water is required, and the present invention provides the following four methods.

(1) liquid phase heat treatment method

The present invention is a "step (a), after the step of (a-1) heating the liquid slurry to lower the moisture content; Cement paste manufacturing method characterized in that it further comprises. This method is to boil by heating the liquid slurry to obtain graphite oxide with reduced water content due to precipitation of graphite oxides by impulse in water. As a result, the volume of liquid slurry is reduced, making it easier to mix cement and water.

(2) chemical treatment

According to the present invention, after the step (a), (a-2) a hydroxy compound of an alkali metal, an alkali metal, a halide compound of an alkaline earth metal, a hydroxy compound of an alkaline earth metal, an amine compound, a strong basic compound in the liquid slurry. Administering any one or more of to remove some of the surface hydrophilic groups of the two-dimensional graphite oxide; Cement paste manufacturing method characterized in that it further comprises.

This method is based on the surface of graphite oxide using alkali metal (Li, Na, K, Rb, Cs), halide (F, Cl, Br, I) compounds of alkaline earth metals and their hydroxy compounds, amines, and strong base compounds. The principle is to remove some of the carboxyl or hydroxy groups. Representative reagents for implementing such a chemical treatment method may be KI, NaOH, Ca (OH) 2, seawater, brine and the like. They can remove some or a substantial amount of surface hydrophilic groups of graphite oxides by chemical causes. By removing some of the surface hydrophilic groups of the two-dimensional graphite oxide in this way, the viscosity of the liquid slurry is lowered, which facilitates mixing of the liquid slurry, cement and water.

(3) UV (including natural light) irradiation treatment

According to the present invention, after the step (a), (a-3) removing the surface hydrophilic group of the two-dimensional graphite oxide by irradiating ultraviolet rays to the liquid slurry; Cement paste manufacturing method characterized in that it further comprises.

Ultraviolet radiation to the liquid slurry can remove a large number of surface hydrophilic groups of the two-dimensional graphite oxide. By removing some of the surface hydrophilic groups of the two-dimensional graphite oxide in this way, the viscosity of the liquid slurry is lowered, which facilitates mixing of the liquid slurry, cement and water. As a similar principle, the effect is further increased when ultraviolet rays are mixed with ceramic powders, that is, oxide semiconductor powders having a photoactive effect (TiO ₂ , WO ₃ , Fe ₂ O _3, etc.), which is because This is because electrons and holes are formed on the semiconductor surface, and these electrons and holes attack two-dimensional graphite oxides to remove surface hydrophilic groups. The added oxide semiconductor powder itself may be used as a cement admixture, mortar and concrete admixture, filler, and the like.

In the mass production of the liquid slurry may have a similar effect even if irradiated with natural light irradiation for one day to several weeks in order to reduce the ultraviolet irradiation cost. This is because natural light contains ultraviolet rays, and ultraviolet rays pass through water.

For example, when the graphite oxide is diluted in a concrete bath on a summer day and the semiconductor oxide powder is stirred and left outdoors, a graphite oxide slurry having a significantly reduced water content can be obtained in only half a day. There are three reasons for this result: heating effect by solar absorption of concrete bath, ultraviolet effect, semiconductor oxide effect by ultraviolet light.

(4) physical precipitation treatment

The present invention, "A after the step (a), (a-4) administering the two-dimensional graphite oxide adsorbent to the liquid slurry; Cement paste manufacturing method characterized in that it further comprises.

This physical precipitation method is different from the above methods (1) to (3), and uses a material capable of adsorbing two-dimensional graphite oxides. Representative materials that can be used in the physical precipitation method include diatomaceous earth, porous silica, fine sludge, fine mud, calcium carbonate, shell shell powder, crab shell powder and the like. That is, the graphite oxides are adsorbed with the adsorbents to precipitate, and the precipitated mixture is relatively reduced in water content. The mixture precipitate solution can be used as it is, or the precipitate is filtered out, semi-dried or completely dried.

Hereinafter, the comparative experimental results for the physical properties of the concrete based on the cement face including the two-dimensional graphite oxide provided by the present invention will be described.

[Table 1] below is a compound table showing the composition of general concrete (hereinafter referred to as 'comparative example') and two-dimensional graphite oxide containing two-dimensional graphite oxide (hereinafter referred to as 'example'). Although not shown in [Table 1], both the comparative example and the example were added with a water reducing agent at a ratio of 0.5 parts by weight to 100 parts by weight of the binder (ie, 1.65 kg / m 3), and the AE agent was added at a ratio of 0.014 with respect to 100 parts by weight of the binder. (Ie, 0.0462 kg / m 3). Comparative Examples and Examples are the same amount of binder, composition of the binder, water-binding ratio, air amount, fine aggregate ratio and the like.

[Table 1]

-W: water,-B: binder,-C: Class 1 ordinary portland cement,

-FA: fly ash,-BFS: blast furnace slag powder, S: fine aggregate,

-G: coarse aggregate,-GO: 2D graphite oxide

-Plain: General concrete without 2D graphite oxide

Example: Concrete containing two-dimensional graphite oxide

W / B: Water-binding ratio (weight ratio of water to 100 parts by weight of binder)

-air: air volume (volume ratio of air to concrete 100 parts by volume)

Table 2 below summarizes the compressive strength of each slump and the age of the comparative example and the example.

[Table 2]

In the case of the above example, the two-dimensional graphite oxide was added 2.2 kg / ㎥ (1.16 parts by weight compared to 100 parts by weight of water), the compressive strength of each age was significantly improved compared to the comparative example, the slump was found to be almost the same level.

none

Claims (8)

Cement paste mixed with two-dimensional graphite oxide, cement and water.
In claim 1,
The two-dimensional graphite oxide is a cement paste, characterized in that 0.01 to 10.0 parts by weight compared to 100 parts by weight of water
(a) preparing a liquid slurry containing two-dimensional graphite oxide; And
(b) mixing the liquid slurry, cement and water; Cement paste manufacturing method comprising a.
According to claim 3, After the step (a) is carried out,
(a-1) lowering the water content by heating the liquid slurry; Cement paste manufacturing method characterized in that it further comprises.
According to claim 3, After the step (a) is carried out,
(a-2) The liquid slurry is administered with at least one of an alkali metal, an alkali metal hydroxy compound, an alkaline earth metal halide compound, an alkaline earth metal hydroxy compound, an amine compound, and a strong base compound to obtain a two-dimensional graphite oxide. Removing some surface hydrophilic groups; Cement paste manufacturing method characterized in that it further comprises.
According to claim 3, After the step (a) is carried out,
(a-3) removing some surface hydrophilic groups of the two-dimensional graphite oxide by irradiating the liquid slurry with ultraviolet rays; Cement paste manufacturing method characterized in that it further comprises.
The method of claim 6,
The step (a-3) is a cement paste manufacturing method, characterized in that by irradiating ultraviolet light after adding the oxide semiconductor powder having a photoactive effect to the liquid slurry.
According to claim 3, After the step (a) is carried out,
(a-4) administering a two-dimensional graphite oxide adsorbent to the liquid slurry; Cement paste manufacturing method characterized in that it further comprises.

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