KR101490502B1 - Mono-fluid type admixture for concrete and preparing the same - Google Patents

Abstract

The present invention relates to a mono-fluid type concrete compound and a method for manufacturing the same. The mono-fluid type concrete compound comprises 5-60wt% of polycarboxylic acid copolymer (A), 14.2-40wt% of inorganic corrosion inhibitor (B), 0.1-10wt% of a phase stabilizer (C), and water (D). The pH of the mono-fluid type concrete compound is greater than 6.4 and lesser than 13.5. The mono-fluid type concrete compound comprises excellent dispersibility, an excellent workability maintenance performance, an excellent corrosion control performance, and excellent long term storage.

Description

Mono-fluid type admixture for concrete and preparing the same

The present invention relates to a one-pack type concrete admixture and a method for producing the same. More particularly, the present invention relates to a one-pack type concrete admixture having excellent dispersibility, workability maintenance performance and rust-inhibitive performance and, above all, excellent long-term storage property, and a method for producing the same.

Concrete admixture is added to concrete and aggregate and water to add dispersibility and fluidity to concrete. These concrete admixtures are classified into mineral admixtures and chemical admixtures, and the chemical admixtures are classified into air entraining admixture, water reducing admixture, and high-performance water reducing agent.

Conventionally, melamine-based or naphthalene-based condensates have been mainly used as high-performance water reducing agents. However, since the polycarboxylic acid system (abbreviated as "PCA") admixture has been developed in Japan in the 1990s, it exhibits excellent dispersibility even when used in a small amount compared with existing naphthalene-based water reducing agents and sufficient workability can be maintained despite high water- Furthermore, PCA-based admixture has become popular because it has superior deformability through control of molecular structure than other kinds of admixture and can be manufactured in various forms.

Recently, the construction of marine concrete structures has been actively carried out in accordance with the trend of reclamation of marine land and construction of offshore structures. However, these marine concrete structures are easily exposed to chloride penetration, and thus are easily corroded. It has been found that the PCA-based admixture, which has been used as a concrete admixture until now, is not suitable for solving the corrosion problem of the concrete structure because there is no corrosion preventing performance (that is, rustproofing performance). Accordingly, in order to improve the rust-preventive performance of the PCA-based admixture, a method of adding an inorganic rust preventive agent to the concrete composition at an appropriate ratio immediately before casting the concrete and using it together with the concrete admixture has been widely practiced.

However, since the long-term strength of the concrete may be lowered by the addition of the inorganic antirust agent, a process or other additive for compensating the physical properties is essential. Depending on the type of the inorganic antirust agent used and the amount of the inorganic antirust agent used, It is difficult to stably and consistently impart desired physical properties to the concrete composition due to differences in physical properties imparted to the composition. In addition, since the above-mentioned method requires separately purchasing and managing the admixture and rustproofing agent from the viewpoints of management and economy, it is difficult to increase the cost of the material and secure the storage space. Therefore, it is necessary to secure a separate storage space or facility So that the management cost is increased.

The above problems can be solved by preparing a one-pack type concrete admixture in which a concrete admixture and an inorganic antirust agent are mixed in advance. However, in the case of preparing a one-pack type concrete admixture by simply mixing a concrete admixture and an inorganic antirust agent, The nitrite of the inorganic antirust agent generates nitrite gas and is difficult to be stored for a long period of time. Also, the produced concrete admixture can not provide sufficient rust inhibitive performance to the concrete composition due to the destruction of the inorganic antirust component due to the reaction as described above. It is very difficult to manufacture a one-pack type concrete admixture which is excellent in long-term storage property and can impart excellent flowability, compressive strength and rust-preventive performance to concrete .

It is an object of the present invention to provide a concrete composition which is excellent in long-term stability and easy to be stored, and which can stably impart dispersibility, workability maintenance performance and rustproofing performance to a concrete composition regardless of the type of an inorganic rust inhibitor to be used, To thereby provide a one-pack type concrete admixture capable of reducing maintenance and maintenance costs.

Another object of the present invention is to provide a method for producing the one-pack type concrete admixture.

In order to accomplish the above object of the present invention, an aspect of the present invention is a thermoplastic resin composition comprising 5 to 60% by weight of a polycarboxylic acid copolymer (A); 14.2 to 40% by weight of an inorganic rust preventive (B); 0.1 to 10% by weight of a phase stabilizer (C); And (D) water as the remainder, and having a pH of 6.4 or more and 13.5 or less.

In one embodiment of the present invention, the polycarboxylic acid-based copolymer (A) may include a structural unit represented by the following formula (1):

≪ Formula 1 >

In Formula 1,

Wherein R ₁ to R ₈ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms and R ₉ is hydrogen, an alkyl group having 1 to 10 carbon atoms or - (C = O) -Z-COOH, And R ₁₀ is an alkylene group having 1 to 5 carbon atoms;

X is a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -OM or an alkyl group having 1 to 10 carbon atoms, wherein M is a 1 to 3 metal cation;

Y is hydrogen or a metal cation of one to three valences;

a is an integer of 1 to 60, b is an integer of 1 to 99, c is an integer of 0 to 99, and d is an integer of 0 to 80;

e is 0 or 1, f is an integer from 0 to 10, g is an integer from 1 to 60; And

h is 0 or 1;

In a further embodiment of the present invention, the polycarboxylic acid-based copolymer (A) may have a weight average molecular weight of 5,000 to 300,000.

In a further embodiment of the present invention, the inorganic rust inhibitor (B) may comprise calcium nitrite (Ca (NO ₂ ) ₂ ), sodium nitrite (NaNO ₂ ), potassium nitrite (KNO ₂ ) or combinations thereof.

In a further embodiment of the invention, the phase-stabilizer (C) is calcium hydroxide (Ca (OH) _2), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), or a combination thereof . ≪ / RTI >

In a further embodiment of the present invention, X in the general formula (1) may be selected from a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -ONa, -OK and an alkyl group having 1 to 10 carbon atoms.

In a further embodiment of the present invention, Y in formula (1) may be Na ⁺ or K ⁺ .

Another aspect of the present invention is to provide a polycarboxylic acid copolymer (A) comprising a structural unit represented by the following formula (1) in a water (D) C) to obtain a first mixture; And (b) adding an inorganic rust inhibitor (B) to the first mixture and stirring the mixture.

≪ Formula 1 >

In Formula 1,

Wherein R ₁ to R ₈ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms and R ₉ is hydrogen, an alkyl group having 1 to 10 carbon atoms or - (C = O) -Z-COOH, And R ₁₀ is an alkylene group having 1 to 5 carbon atoms;

X is a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -OM or an alkyl group having 1 to 10 carbon atoms, wherein M is a 1 to 3 metal cation;

Y is hydrogen or a metal cation of one to three valences;

a is an integer of 1 to 60, b is an integer of 1 to 99, c is an integer of 0 to 99, and d is an integer of 0 to 80;

e is 0 or 1, f is an integer from 0 to 10, g is an integer from 1 to 60;

h is 0 or 1;

The one-pack type concrete admixture of the present invention can provide a concrete composition excellent in dispersibility and workability maintaining performance while maintaining excellent rust-inhibiting performance. Also, the one-pack type concrete admixture of the present invention is prepared in one-pack form by the combination of the PCA-based admixture and the inorganic antirust agent, so that the concrete composition can be stably and consistently provided with fluidity and rustproofing performance irrespective of kinds of the admixture and the inorganic rust- .

In addition, the one-pack type concrete admixture of the present invention facilitates the management of the admixture and the inorganic antirust agent due to the simplification of the storage space or the facility, and can further reduce the management cost and the material cost.

As used herein, the term "alkyl group" means a linear or branched aliphatic hydrocarbon monovalent group, and specific examples thereof include methyl, ethyl, propyl, isobutyl, sec-butyl, , Pentyl group, iso-amyl group, hexyl group and the like.

As used herein, the term "alkylene group" means a divalent group having the same structure as the above alkyl group.

In the present specification, the term "alkenyl group " means a hydrocarbon group having one or more carbon double bonds at the middle or end of the alkyl group, and specific examples thereof include an ethenyl group, a propenyl group and a butenyl group.

In the present specification, the term "alkenylene group" means a divalent group having the same structure as the alkenyl group.

Hereinafter, a one-pack type concrete admixture according to a specific embodiment of the present invention will be described in more detail.

The one-pack type concrete admixture according to one embodiment of the present invention comprises 5 to 60% by weight of the polycarboxylic acid-based copolymer (A); 14.2 to 40% by weight of an inorganic rust preventive (B); 0.1 to 10% by weight of phase stabilizer (C); And (D) water as the remainder, and the pH is 6.4 or more and 13.5 or less.

The polycarboxylic acid-based copolymer (A) serves as the base of a one-pack type concrete admixture. The copolymer has a polyethylene oxide chain called a side chain in the polymer to form a three-dimensional steric molecular structure, The concrete particles are dispersed by the repulsive force to increase the fluidity of the concrete composition.

The polycarboxylic acid-based copolymer (A) may include a structural unit represented by the following formula (1)

≪ Formula 1 >

In Formula 1, R ₁ to R ₈ may each independently be hydrogen or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 2 to 5 carbon atoms.

In the above formula (1), R ₉ represents hydrogen, an alkyl group having 1 to 10 carbon atoms or - (C = O) -Z-COOH, where Z may be an alkylene group or an alkenylene group having 2 to 20 carbon atoms.

In Formula 1, R ₁₀ may be an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms.

In Formula 1, X may be a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -OM or an alkyl group having 1 to 10 carbon atoms, wherein M may be a metal cation of 1 to 3 valence, 1, X may be a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -ONa, -OK or an alkyl group having 1 to 10 carbon atoms, more preferably X may be -ONa or -OK.

In the above formula (1), Y may be hydrogen or a metal cation of 1 to 3 valences, preferably Na ⁺ , K ⁺ or Ca ^{2 +} .

In Formula 1, a may be an integer of 1 to 60, preferably an integer of 2 to 30. In the above formula (1), when a is within the above range, the concrete fluidity, that is, the initial dispersing force and the retention force, are effective.

In Formula 1, b may be an integer of 1 to 99, preferably an integer of 1 to 60, and more preferably an integer of 30 to 75. In the above formula (1), when b is within the above range, when X is a hydroxyl group or -OM, the concrete dispersing ability is improved, and when X is other functional group, the workability maintenance performance is improved.

In the above formula (1), c may be an integer of 0 to 99, preferably an integer of 1 to 60, and more preferably an integer of 2 to 30. In the above formula (1), when c is within the above range, the dispersibility of concrete is improved.

In the above formula (1), d may be an integer of 0 to 80, preferably an integer of 1 to 40. In the above formula (1), when d is within the above range, the concrete dispersibility is improved.

In the above formula (1), e may be 0 or 1, preferably e may be 1. That is, when e is 0, the polycarboxylic acid-based copolymer is an ether type, and when e is 1, the polycarboxylic acid-based copolymer is an ester type. In the above formula (1), f may be an integer of 0 to 10, preferably, f may be an integer of 1 to 5.

In the above formula (1), g may be an integer of 1 to 60, preferably g may be an integer of 45 to 55.

In the above formula (1), h may be 0 or 1, preferably h may be 1.

 The polycarboxylic acid-based copolymer (A) may have a weight average molecular weight of 5,000 to 300,000, preferably 7,000 to 100,000, more preferably 9,000 to 80,000, and still more preferably 10,000 to 70,000. When the weight average molecular weight of the polycarboxylic acid copolymer (A) is within the above range, the dispersibility and workability of the concrete admixture are excellent.

If the content of the polycarboxylic acid-based copolymer (A) is 5 wt% or less based on the total weight of the one-pack type concrete admixture, the dispersibility and workability of the admixture are insufficient and the fluidity of the concrete composition is very small (H ⁺ ) is excessively increased in the admixture, the nitrite gas is generated by the reaction with the nitrite to increase the instability of the admixture, and the viscosity of the admixture thus prepared is increased. Which is very difficult and therefore difficult to use in concrete compositions. The content of the polycarboxylic acid copolymer (A) may preferably be 20 to 40% by weight based on the total weight of the one-pack type concrete admixture.

The one-pack type concrete admixture of the present invention may contain the above polycarboxylic acid copolymer (A) alone or as a mixture of two or more kinds. The one-pack type concrete admixture of the present invention may contain, in addition to the polycarboxylic acid copolymer (A), other polymers known for concrete admixtures, for example, a conventional polycarboxylic acid polymer, a naphthalene polymer, a melamine polymer A polymer, and a polyurethane-based polymer.

The inorganic anticorrosive agent (B) serves to prevent the corrosion of the concrete structure in the air by giving the corrosion inhibiting property to the concrete composition.

The inorganic rust inhibitor (B) may comprise calcium nitrite (Ca (NO ₂ ) ₂ ), sodium nitrite (NaNO ₂ ), potassium nitrite (KNO ₂ ) or combinations thereof.

If the content of the inorganic anticorrosive agent (B) is 14.2% by weight or less based on the total weight of the one-pack type concrete admixture, sufficient rust inhibitive performance of the concrete composition is difficult to exhibit. If the content is 40% by weight or more, the long- .

The phase stabilizer (C) can be produced by adjusting the pH in the aqueous solution to alkaline in the preparation of the one-pack type concrete admixture to remove the protons generated from the polycarboxylic acid copolymer (A) . When the nitrite gas is generated by the protons as described above, the prepared one-pack type concrete admixture is very unstable and difficult to be stored for a long period of time. As the inorganic anticorrosive component (B) is destroyed, the anticorrosion performance of the concrete can not be sufficiently provided.

Wherein the stabilizer (C) may comprise calcium hydroxide (Ca (OH) _2), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), or a combination thereof.

When the content of the phase stabilizer (C) is 0.1% by weight or less based on the total weight of the one-pack type concrete admixture, nitrous gas is easily generated by the protons generated from the polycarboxylic acid copolymer (A) %, The flowability of the concrete composition is lowered. The amount of the phase stabilizer (C) may preferably be 0.26 to 0.96% by weight based on the total weight of the one-pack type concrete admixture.

The one-pack type concrete admixture should be controlled to have a pH of 6.4 to 13.5. When the pH of the one-pack type concrete admixture is less than 6.4, excess protons in the admixture react with the nitrite to release the nitrite gas. As a result, it is difficult to impart dispersibility and workability maintenance to the concrete composition as an admixture, There is a risk of explosion due to the nitrite gas, and the nitrite gas is very harmful to the human body and is very difficult to handle. In addition, concrete admixtures having a pH of more than 13.5 are difficult to produce by the production facilities currently used in the related art.

Accordingly, the one-pack type concrete admixture of the present invention can be controlled to have a pH of 6.4 or more and 13.5 or less, and as a result, there is no gas generation problem due to protons in the admixture, so that the one-pack type can conveniently and effectively disperse, . Specifically, by using the one-pack type concrete admixture of the present invention, there is no need to separately manage the PCA-based admixture and the inorganic antirust agent, and it is easy to store for a long period of time because no nitrite gas is generated when the PCA- Since the inorganic rust inhibitor component is not destroyed, the rustproofing performance can be imparted to the concrete composition and the dispersibility and the fluidity can be imparted to the concrete composition stably regardless of the inorganic rust inhibitor to be used. Further, by using the one-pack type concrete admixture of the present invention, it is possible to obtain a concrete excellent in workability maintaining performance, compressive strength and rust-preventing performance, without deteriorating the long-term compressive strength of the concrete due to addition of the inorganic antirust agent.

The method for producing the one-pack type concrete admixture according to another aspect of the present invention will be described in detail. (A) mixing the polycarboxylic acid copolymer (A) containing the structural unit represented by the formula (1) with the phase stabilizer (C) in water (D) to obtain a first mixture; And (b) adding the inorganic rust inhibitor (B) to the first mixture and stirring the mixture. In the above steps (a) and (b), the polycarboxylic acid copolymer (A), the inorganic anticorrosive agent (B), the phase stabilizer (C) and the water (D) Can be used in the same amount.

In the above production process, steps (a) and (b) may be carried out at room temperature (25 ° C) and may be carried out using a known stirring apparatus. The stirring device may be, for example, a mechanical stirrer, a double helix mixer, a high-speed emulsifier, a homogenizer, a high shear blender or an ultrasonic homogenizer, But are not limited to:

In the above production method, it is preferable that the polycarboxylic acid copolymer (A) and the phase stabilizer (C) are first stirred in water, and then the inorganic anticorrosive (B) is further added and stirred.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood that these embodiments are provided for the purpose of more specifically illustrating the embodiments of the present invention and are not intended to limit the scope of the present invention.

Example

Example  1 to 18 and Comparative Example  1 to 28

(Preparation of one-pack type concrete admixture)

A 1000 g reactor equipped with a stirrer was charged with the polycarboxylic acid copolymer (A) (trade name: 500FR, manufactured by Silk Road Co., Ltd., weight average molecular weight: 45,000), calcium hydroxide (C) and water And stirred at about 20 [deg.] C for 2 hours. As a result, a first mixture was obtained. Then, calcium nitrite (B) was added to the first mixture, and the mixture was stirred at about 20 ° C for 1 hour. As a result, a second mixture (referred to as " one-pack type concrete admixture ") was obtained. The types and amounts of the components used in the above Examples and Comparative Examples are shown in Table 1 below. In the following Table 1, the units of (A), (B), (C) and (D) are% by weight and the sum of (A), (B), (C) and (D) is 100% by weight.

(A) (B) (C) (D) Example 1 5 14.2 0.33 80.47 Example 2 5 14.2 0.40 80.00 Example 3 5 14.2 0.49 79.91 Example 4 5 40 0.26 54.74 Example 5 5 40 0.30 54.40 Example 6 5 40 0.36 54.34 Example 7 20 14.2 0.53 65.27 Example 8 20 14.2 0.60 65.20 Example 9 20 14.2 0.69 65.11 Example 10 20 40 0.46 39.54 Example 11 20 40 0.50 39.50 Example 12 20 40 0.56 39.44 Example 13 40 14.2 0.78 45.02 Example 14 40 14.2 0.85 44.95 Example 15 40 14.2 0.94 44.86 Example 16 40 40 0.71 19.29 Example 17 40 40 0.75 19.25 Example 18 40 40 0.81 19.19 Comparative Example 1 5 13.5 0.12 81.38 Comparative Example 2 5 13.5 0.34 81.16 Comparative Example 3 5 13.5 0.35 81.15 Comparative Example 4 5 13.5 0.43 81.07 Comparative Example 5 5 13.5 0.51 80.09 Comparative Example 6 5 14.2 0.10 80.70 Comparative Example 7 5 14.2 0.32 80.48 Comparative Example 8 5 40 0.05 54.95 Comparative Example 9 5 40 0.25 54.75 Comparative Example 10 20 13.5 0.31 66.19 Comparative Example 11 20 13.5 0.53 65.97 Comparative Example 12 20 13.5 0.55 65.95 Comparative Example 13 20 13.5 0.62 65.88 Comparative Example 14 20 13.5 0.71 65.79 Comparative Example 15 20 14.2 0.30 65.50 Comparative Example 16 20 14.2 0.52 65.28 Comparative Example 17 20 40 0.23 39.77 Comparative Example 18 20 40 0.45 39.55 Comparative Example 19 40 13.5 0.57 45.93 Comparative Example 20 40 13.5 0.78 45.72 Comparative Example 21 40 13.5 0.79 45.71 Comparative Example 22 40 13.5 0.87 45.63 Comparative Example 23 40 13.5 0.96 45.54 Comparative Example 24 40 14.2 0.55 45.25 Comparative Example 25 40 14.2 0.77 45.03 Comparative Example 26 40 40 0.48 19.82 Comparative Example 27 40 40 0.70 19.60 Comparative Example 28 20 14.2 11 54.8

(Preparation of concrete composition)

Using the one-pack type concrete admixtures prepared in Examples 4, 7-8 and 11 and Comparative Examples 8, 13, 16 and 28, a concrete composition was prepared as shown in Table 2 below.

W / B
(%) S / A
(%) Weight unit (kg / m ³ ) AD (%) water cement Slag
powder Fly
ash Washing machine Goodwill 25mm coarse aggregate 1.08 44.6 48 165 178 118 74 495 330 911

※ W / B: Water / Binder (Cement + Fly Ash + Slag Powder)

※ S / A: Washer + Crusher / 25mm coarse aggregate

* AD: Based on the total weight of the binder, the addition amount of the one-component concrete admixture of the present invention

※ Cement (Chunmarta Cement, Sungshin Cement Co., Ltd.), Fly Ash (Taean Thermal Power Co., Ltd.)

Evaluation example

Evaluation example  One: One-pack type  Evaluation of physical properties of concrete admixture

(pH evaluation)

The pH of each one-pack type concrete admixture prepared in Examples 1 to 18 and Comparative Examples 1 to 28 was measured using a pH meter (instrument: pH Meter D-51, manufactured by HORIBA). The results are shown in Table 3 below.

(Evaluation of the presence or absence of nitrite gas)

Each of the one-pack concrete admixtures prepared in Examples 1 to 18 and Comparative Examples 1 to 28 was evaluated for the presence or absence of nitrite gas by visual observation and evaluated according to the following criteria. The results are shown in Table 3 below.

○ Good: No air bubbles

× poor: observation of bubble generation

pH Whether nitrite gas is generated Example 1 6.4 ○ Example 2 9.0 ○ Example 3 13.5 ○ Example 4 6.4 ○ Example 5 9.0 ○ Example 6 13.0 ○ Example 7 6.4 ○ Example 8 9.0 ○ Example 9 13.5 ○ Example 10 6.4 ○ Example 11 9.0 ○ Example 12 13.5 ○ Example 13 6.4 ○ Example 14 9.0 ○ Example 15 13.5 ○ Example 16 6.4 ○ Example 17 9.0 ○ Example 18 13.5 ○ Comparative Example 1 5.0 × Comparative Example 2 6.3 × Comparative Example 3 6.4 ○ Comparative Example 4 9.0 ○ Comparative Example 5 13.5 ○ Comparative Example 6 5.0 × Comparative Example 7 6.3 × Comparative Example 8 5.0 × Comparative Example 9 6.3 × Comparative Example 10 5.0 × Comparative Example 11 6.3 × Comparative Example 12 6.4 ○ Comparative Example 13 9.0 ○ Comparative Example 14 13.5 ○ Comparative Example 15 5.0 × Comparative Example 16 6.3 × Comparative Example 17 5.0 × Comparative Example 18 6.3 × Comparative Example 19 5.0 × Comparative Example 20 6.3 × Comparative Example 21 6.4 ○ Comparative Example 22 9.0 ○ Comparative Example 23 13.5 ○ Comparative Example 24 5.0 × Comparative Example 25 6.3 × Comparative Example 26 5.0 × Comparative Example 27 6.3 × Comparative Example 28 13.5 ○

Referring to Table 3, it was confirmed that the nitric acid gas was not generated by controlling the pH of the one-pack type concrete admixture prepared in Examples 1 to 18 from 6.4 to 13.5. However, the one-pack type concrete admixture prepared in Comparative Examples 1, 2, 6-11, 15-20 and 24-27 had a pH of less than 6.4 and a nitrite gas was generated.

Therefore, when the pH of the prepared one-pack type concrete admixture is controlled to 6.4 or more and 13.5 or less, there is no problem of generation of nitrite gas by protons in the admixture at the time of manufacture, Dispersibility, fluidity and rust-inhibiting properties can be imparted. However, when the pH is less than 6.4, it is not easy to handle because of the risk of explosion due to the nitrite gas generated during the production, and it is very harmful to the human body, so that it can not be used practically.

However, the one-pack type concrete admixture prepared in Comparative Examples 3-5, 12-14, 21-23 and 28 did not cause problems due to the nitrite gas by controlling the pH to be 6.4 or higher. However, as described later, It was not exercised.

Evaluation example  2: Evaluation of physical properties of concrete composition

(Workability maintenance performance evaluation A: flow value)

Concrete was prepared and mixed according to the composition shown in Table 2 to prepare concrete, the concrete was filled into a flow cone having a diameter of 20 cm and a height of 30 cm, the cone was vertically lifted, After the loading was completed, the diameter of the concrete spreading in the flow table was measured at the initial stage of mixing and after 30 minutes of mixing with respect to the two directions, and the average value was defined as the flow value (mm). The results are shown in Table 4 below.

(Workability maintenance performance evaluation B: slump)

The concrete compositions were prepared and mixed according to the compositions shown in Table 2 above to prepare concrete, and the concrete was slump tested according to KS F 2402 for 30 minutes immediately after being discharged from the mixer. The results are shown in Table 4 below.

(Evaluation of compressive strength)

Concrete was manufactured using the concrete composition according to the composition shown in Table 2 above, and three circular specimens of? 100x200 mm were prepared by using the concrete, and curing was carried out at 20 占 폚 under a dry condition (humidity 65? 5% 3 "," 7 "," 14 ", and " 28 ", in accordance with KS F 2405 " Method for preparing concrete specimen for strength test of concrete ", using a compressive strength meter (HCT-CS300, The results are shown in Table 4 below.

(Evaluation of rust prevention performance)

The concrete was prepared using the concrete composition according to the composition shown in the above Table 2, and the "concrete reinforcing corrosion test" of KS F 2561 was performed using the concrete. A polycarboxylic acid type copolymer (trade name: 300 NX, manufactured by Silk Road Co., Ltd.) was used as a plain sample to which the rust preventive agent was not applied for the calculation of the rust prevention rate (%). The prepared concrete composition was mixed to prepare concrete, and reinforcing bars were inserted to prepare specimens. The specimen was placed in an autoclave and cured twice at a temperature of 180 ° C and 1.0 MPa for more than 5 hours to accelerate the corrosion of the reinforcing bars. The reinforcing bars were taken out to measure the corrosion area, and the rusting rate Respectively. When the corrosion area of the plane specimen is taken as 100%, it is evaluated that it has a rust prevention effect when the reduction effect is more than 95%. The results are shown in Table 4 below.

[Equation 1]

(%) = 1 - [Corrosive area of evaluation sample / Corrosion area of plain sample] × 100

Flow value (mm) /
Slump (mm) Compressive strength (MPa) Rust prevention rate (%) Anti-rust effect Early 30 minutes later 3 days 7 days 28th Example 4 - / 65 - / 65 10.71 22.09 34.22 97.27 ○ Example 7 370/215 480/230 10.32 21.71 33.88 95.29 ○ Example 8 365/215 490/235 10.09 21.93 34.23 95.40 ○ Example 11 365/215 490/235 10.55 21.90 33.91 97.00 ○ Comparative Example 8 - / 65 - / 65 10.60 21.99 34.21 94.03 × Comparative Example 13 370/215 460/230 9.92 21.50 33.70 93.90 × Comparative Example 16 360/210 450/225 10.09 21.71 33.79 93.75 × Comparative Example 28 - / 50 - / 50 9.89 21.09 33.35 95.33 ○

※ "-": Can not be measured

Referring to Table 4, the concrete composition prepared by using the one-pack type concrete admixture prepared in Example 7 was improved in flow property and flow property (i.e., workability maintenance performance) by keeping the flow value and slump high, The initial flow (ie, dispersibility) was also excellent due to high flow value and initial slump, and there was no decrease in compressive strength and the rustproofing performance was also excellent. However, in the concrete composition prepared using the one-pack type concrete admixture prepared in Comparative Example 16, the flow value was lower than the initial flow value after 30 minutes and the workability maintenance performance was insufficient. Accordingly, it can be seen that the concrete composition prepared by using the one-pack type concrete admixture of the present invention having a pH of 6.4 or more is excellent in dispersibility, workability maintenance performance, compressive strength and rustproofing performance.

The concrete composition prepared using the one-pack type concrete admixture prepared in Example 8 exhibited excellent anticorrosive performance. However, the concrete composition prepared using the one-pack type concrete admixture prepared in Comparative Example 13 had insufficient rust inhibitive performance. Therefore, when the one-pack type concrete admixture of the present invention contains the inorganic anticorrosive (B) in an amount of 14.2% by weight or more, the produced concrete composition is excellent in anticorrosive performance, but when it is contained in an amount of less than 14.2% The effect does not appear. Also, the concrete composition prepared using the one-pack type concrete admixture prepared in Example 4 was excellent in anti-rust performance. However, the concrete composition prepared using the prepared one-pack type concrete admixture prepared in Comparative Example 8 had insufficient rust inhibitive performance. Therefore, when the one-pack type concrete admixture of the present invention contains the inorganic anticorrosive agent (B) in an amount of less than 0.1% by weight, sufficient anticorrosive effect is not exhibited.

The concrete composition prepared by using the one-pack type concrete admixture prepared in Example 8 was improved in workability maintenance performance by keeping the flow value high, and the initial flow was also high, so that the initial flowability was also excellent and there was no decrease in compressive strength And the rustproofing performance was also excellent. However, the concrete composition prepared using the one-pack type concrete admixture prepared in Comparative Example 28 had insufficient dispersibility due to a very low initial flow value, and the rust-inhibitive performance was also insufficient. Therefore, when the one-pack type concrete admixture of the present invention contains the phase stabilizer (C) in an amount of 11% by weight or less, the prepared concrete composition is excellent in dispersibility and rustproofing property but is contained in an amount exceeding 11% , It can be seen that the dispersibility and the anti-rusting performance are not sufficient.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (10)

5 to 60% by weight of a polycarboxylic acid-based copolymer (A);
14.2 to 40% by weight of an inorganic rust preventive (B);
0.1 to 10% by weight of a phase stabilizer (C); And
(D) water as the remainder,
The weight ratio of the polycarboxylic acid copolymer (A) to the inorganic anticorrosive (B) is 1: 0.355 to 1: 8,
A one-component concrete admixture having a pH of 6.4 to 13.5. The one-pack type concrete admixture according to claim 1, wherein the polycarboxylic acid copolymer (A) comprises a structural unit represented by the following formula (1)
≪ Formula 1 >

In Formula 1,
Wherein R ₁ to R ₈ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms and R ₉ is hydrogen, an alkyl group having 1 to 10 carbon atoms or - (C = O) -Z-COOH, And R ₁₀ is an alkylene group having 1 to 5 carbon atoms;
X is a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -OM or an alkyl group having 1 to 10 carbon atoms, wherein M is a 1 to 3 metal cation;
Y is hydrogen or a metal cation of one to three valences;
a is an integer of 1 to 60, b is an integer of 1 to 99, c is an integer of 0 to 99, and d is an integer of 0 to 80;
e is 0 or 1, f is an integer from 0 to 10, g is an integer from 1 to 60;
h is 0 or 1; The one-pack type concrete admixture according to claim 1, wherein the polycarboxylic acid copolymer (A) has a weight average molecular weight of 5,000 to 300,000. The one-pack type concrete admixture according to claim 1, wherein the inorganic rust inhibitor (B) comprises calcium nitrite (Ca (NO ₂ ) ₂ ), sodium nitrite (NaNO ₂ ), potassium nitrite (KNO ₂ ) or a combination thereof. 2. The method of claim 1, wherein the stabilizer (C) comprises calcium hydroxide (Ca (OH) _2), sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), or a combination thereof One pack concrete admixture. The one-pack type concrete admixture according to claim 1, wherein the content of the polycarboxylic acid copolymer (A) is 20 to 40% by weight. The one-pack type concrete admixture according to claim 1, wherein the content of the phase stabilizer (C) is 0.26 to 0.94% by weight. The one-pack type concrete admixture according to claim 2, wherein X in the general formula (1) is selected from the group consisting of a hydroxyl group, a methoxy group, an ethoxy group, an amino group, -ONa, -OK and an alkyl group having 1 to 10 carbon atoms. The method of claim 2, wherein the one-part concrete admixture in the above general formula (1) Y is a Na ^+, K ⁺ and Ca ^{2 +} choose from. delete