KR100823986B1 - A method of manufacturing a low elasticity polymer concrete admixture for inhibiting of alkali aggregate reaction - Google Patents

Abstract

A method for manufacturing a low-elastic polymer concrete admixture is provided to produce the admixture that has inhibitory performance of an alkali aggregate reaction, allows quick hardening, is producible in ready-mixed concrete, and ensures workability. A method for manufacturing a low-elastic polymer concrete admixture for inhibiting an alkali aggregate reaction includes the steps of: adding a first admixture and a second admixture to concrete comprising cement, sand, pebbles, and water; and mixing the added first and second admixtures and the concrete. The first admixture comprises (A) a re-dispersible powder polymer resin, (B) a polycarbonic acid-based powder dispersant, (C) lithium hydroxide, lithium nitrate, or lithium nitrite, (D) an antifoaming agent, and (E) at least any one selected from thickeners comprising cellulose, polyvinyl alcohol, polysaccharide, and aluminum magnesium silicate. The second admixture comprises (a) calcium aluminate or amorphous hydroxide, and (b) amorphous aluminum hydroxide or metal aluminate salt.

Description

A method of manufacturing a low elasticity polymer concrete admixture for inhibiting of alkali aggregate reaction

The present invention relates to a low elastic polymer concrete admixture manufacturing method, and more particularly to a low elastic polymer concrete admixture manufacturing method for inhibiting the alkali aggregate reaction that can be produced in ready-mixed concrete.

In recent years, concrete structures require high reconstruction and weather resistance, and these concretes are getting stronger. However, as the concrete ages, the aging of the surface easily breaks due to changes in the use environment. The use of aggregates containing a large amount causes alkali aggregate reactions and is found in the form of cracks on the surface.

Repair of these failure sites in concrete structures is essential to reduce the enormous economic costs of reconstruction and to prevent accidents. Particularly, in the case of concrete pavement, partial cross-section repair is being performed to repair it, and it is repaired using LMC (Latex Modified Concrete). Its pavement thickness is at least about 30mm, and usually 50mm is applied, so the economic cost of reconstruction is considerable.

Recently, a method using a polymer such as LMC can be used for both partial repair or total repair and new construction. However, the amount of polymer used is usually economical because it reaches 30% by weight of the cement weight. In addition, the difficulty of the initial crack control during construction and the high price limit of the installation thickness of the LMC is raised as a problem, despite their excellent performance, it is mainly used only in large bridges.

First, looking at domestic patents, Republic of Korea Patent No. 10-89579 discloses emergency road repair materials. As disclosed, the material used is asphalt as the main material, which is a mixture of tar, acrylic modified butadiene polymer, potassium chloride, and the like, a mixture of crushed aggregate and portland cement, and no binder.

 However, according to the registered patent No. 10-89579, the asphalt has to be maintained at a high temperature, and thus have problems such as plastic shrinkage and problems to be produced at a suitable distance.

In addition, Republic of Korea Patent No. 10-0313599 discloses a modified concrete for impervious bridge surface pavement. Impervious polymer concrete is composed of cement 11-14 (w / w%), sand 35-40 (w / w%), gravel 25-27 (w / w%) and synthetic rubber latex (solid content 45%) 17-22 (w / w%) is disclosed.

This proves that it has excellent adhesion and maintains high density, so it is excellent in resistance to salts, but it is not economical due to the large amount of polymer such as synthetic rubber latex, and it is not economical as the shrinkage of plastic shrinkage due to shrinkage of LMC during curing and drying. There was a very likely problem. In addition, there is a problem that must be prepared by the construction of concrete at the site, so for the construction of the aggregate and cement, and other admixtures at the site, the construction restrictions in the city had a very big disadvantage.

In the case of Republic of Korea Patent No. 10-0421255, the concrete or mortar containing synthetic rubber latex and the waterproof packaging method using them, except that only 5 to 6% by weight of synthetic rubber latex (SBR Latex) is different, the above-mentioned registered patent Similar to No. 10-0313599, but in the case of registered patent No. 10-0421255, the purpose itself is limited to the use of waterproofing.

In addition, the Republic of Korea Patent No. 10-0537953 relates to a method for producing a latex modified cemented carbide concrete composition, similar to the above Patent Registration No. 10-0421255, but using cement as a fast cement to speed up the opening of traffic. It is suitable for emergency repair of concrete structures, roads, bridge decks, etc. However, this also has the disadvantage of having to prepare concrete at the site by preparing all the cement aggregates, admixtures and the like.

Korean Patent Application Publication No. 10-2005-0029882 discloses a method for repairing and reinforcing a concrete structure by a high pressure dry spray method of powdered polymer mortar. The powdered polymer mortar is mixed with water at the moment of spraying by high pressure spray method and the mortar is prepared and sprayed.

However, this also presents a method of making the powder directly mortar in the field, causing problems such as the generation of scattering dust and loading the sample on site.

In addition, the Republic of Korea Patent Registration No. 10-0586644 MMA (methyl methacrylate) modified eco-porous concrete and its manufacturing method is a conventional polymer concrete that does not harden the cement, the conventional conventional concrete using MMA as a binder Advantages such as wear resistance and economy after curing have been lost. The performance of polymer concrete is very good, but there is a possibility of deterioration due to ultraviolet rays and an increase in material cost due to an increase in poly content. There is a possibility of environmental pollution due to the use of a large amount of polymer.

The method of overlaying a thin layer on an existing asphalt pavement using the Republic of Korea Patent No. 10-0621355 polymer concrete can also be seen to be the same as the polymer concrete described above.

On the other hand, there is a Republic of Korea Patent No. 10-0670458 as the technology most similar to the present invention. Patent No. 10-670458 discloses a dry concrete composition for repair / reinforcement, a manufacturing method thereof, and a repair method using the same, including cemented carbide, a high-strength mixture, a calcium sulfone aluminate-based anhydrous storage material, and powdered resin. have.

This is suitable for manufacturing concrete for fast diameter, but when it is used, the work deterioration time of concrete is very short, and thus it is impossible to use it when manufactured and transported in ready-mixed concrete (hereinafter referred to as "mixed concrete").

In other words, the conventional polymer concrete is manufactured in ready-mixed concrete, etc., so that it is difficult to reach the site, and adopts a method of manufacturing polymer concrete in the field, and also adds additives separately because it does not secure multifunctional functions such as breathability, alkali aggregate reaction suppression function and waterproofness. There is a hassle and is produced very expensively.

Therefore, while it is possible to control the rate of hardening of concrete, the development of concrete that can be manufactured in ready-mixed concrete, etc. is required, and also due to the heterogeneity or lack of breathability with the conventional concrete surface generated during concrete repair, There is a need for a way to solve the problem of dropout.

Throughout this specification many patent documents are referenced and their citations are indicated. The disclosures of the cited patent documents are incorporated by reference herein in their entirety, and the level of the technical field to which the present invention belongs and the contents of the present invention are more clearly described.

Therefore, an object of the present invention is to provide a method for producing a low elastic concrete admixture having a suppressing ability of alkali aggregate reaction, in order to solve the above problems.

In addition, an object of the present invention is a fast-mixing admixture, by further adding a coagulation accelerator and coagulation aid, and by adjusting the amount of use thereof can be rapidly cured, can be produced in ready-mixed concrete (ready mixed concrete), and workability can also be secured It is to provide a method for producing a mixed material for low-elastic concrete.

Other objects and advantages of the present invention will become apparent from the following examples, effects, claims, and the like.

In order to achieve the above object, the method for producing a low elastic polymer concrete admixture for suppressing alkali aggregate reaction according to the present invention is (A) redispersible powder polymer resin, (B) polycarboxylic acid-based powder dispersant, (C) lithium hydride At least one of a hydroxide (LiOH), lithium nitrate (LiNO ₃ ) or lithium nitrite (LiNO ₂ ), (D) defoamer and (E) a thickener consisting of cellulose, polyvinyl alcohol, polysaccharide and aluminum magnesium silicate Including a first admixture comprising a concrete, consisting of cement, sand, gravel and water and mixing the injected first admixture and the concrete.

Preferably, the step of injecting is characterized in that the second admixture further comprises (a) calcium aluminate or amorphous hydroxide and (b) amorphous aluminum hydroxide or aluminate metal salt.

In addition, the first admixture is (A) 20 to 70% by weight redispersible powder polymer resin, (B) 5 to 25% by weight polycarboxylic acid-based powder dispersant, (C) lithium hydroxide, lithium nitrate or lithium nitrite 10 to 25% by weight of light, (D) 1 to 10% by weight of antifoaming agent, and (E) 1 to 10% by weight of thickener consisting of cellulose, polyvinyl alcohol and aluminum magnesium silicate.

In addition, the second admixture may include a) 50 to 90 wt% of a) calcium aluminate or amorphous hydroxide and (b) 10 to 50 wt% of amorphous aluminum hydroxide or aluminate metal salt.

In addition, the first admixture preferably contains 7 to 13% by weight based on the weight of the cement.

In addition, the second admixture preferably contains 8 to 15% by weight based on the weight of the cement.

In addition, the concrete is preferably ready-mixed concrete.

The present inventors have made diligent efforts to develop a composition and construction method of an improved multi-functional concrete horn fire that solves the above-mentioned demands of the art. As a result, only about 2 hours of work is performed by mixing a mixed material for polymer concrete with concrete. Ready-mixed polymer concrete that can maintain the castle was able to be prepared, it was also possible to improve the physical properties of the conventional concrete.

In addition, the addition of the low-elasticity concrete admixture according to the present invention improves adhesion and breathability, maintains similarity with the conventional concrete surface, and can produce and sell low-elasticity concrete in ready-mixed concrete, regardless of site conditions. Can be constructed, there is an effect that can adjust the curing rate of the concrete by the ratio of the additive.

The present invention is a low-elastic polymer for inhibiting alkali aggregate reaction by separating the first admixture, which is a low elastic admixture, and the second admixture, which is a fast curing admixture, and adding the appropriate amount of the admixture into concrete composed of cement, gravel, water, and sand. A concrete admixture was prepared.

Preferably, the first admixture is (A) redispersible powder polymer resin, (B) polycarboxylic acid powder dispersant, (C) lithium hydroxide, lithium nitrate or lithium nitrite, (D) antifoaming agent and (E A thickener consisting of cellulose, polyvinyl alcohol, polysaccharide and aluminum magnesium silicate.

In addition, the second admixture for adjusting the curing rate is preferably composed of (a) calcium aluminate and (b) amorphous aluminum hydroxide or aluminate metal salt.

For reference, the polymer concrete admixture refers to a composition of admixtures capable of adding physical properties of polymer concrete to general concrete made of a mixture of cement, sand, and water.

Hereinafter, the purpose and the appropriate content of the components constituting the first and second admixtures of the present invention as described above will be described.

First, the redispersible powdered polymer resin of (a) in the first admixture has already been reported a lot, but is manufactured by each manufacturer based on acrylate, styrene, EVA (Ethylene Vinil Acetate), etc. Does not significantly affect the amount of air or slump. In particular, manufacturers include Wacker, Houcst and BASF of Germany, and polymer concrete or mortar using them are widely used in repairs. A suitable amount of use is suitably 20 to 70% by weight in the first admixture. If less than 20% by weight of the polymer concrete does not appear, if more than 70% by weight it is difficult to form a multifunctional admixture.

(B) The polycarboxylic acid-based powder dispersant in the first admixture is a powdered liquid polycarboxylic acid-based dispersant, which has already been proven to have excellent dispersibility, but shows a slight performance change depending on the type of cement and the degree of powder. In most concrete, workability is about 1 to 2 hours. Suitable amounts of 5 to 25% by weight of the first admixture is suitable, if less than 5% by weight of the workability of the polymer concrete may deteriorate sharply, if it exceeds 25% by weight it may be lowered by the aggregate separation.

In addition, (c) lithium hydroxide, lithium nitrate or lithium nitrite is a powder coagulation accelerator having excellent alkali aggregate reaction inhibiting ability and having fast coagulation promoting properties. A suitable amount of use is preferably 10 to 25% by weight in the first admixture. If less than 10% by weight of alkali aggregate reaction suppression ability is less, when more than 25% by weight of the rapid cement reaction occurs difficult to use.

In addition, (d) defoamer was used to control the amount of air by adding a powder carboxylic acid-based dispersant to lower the amount of air entrained when producing concrete. It is preferable to use a silicone type as an antifoamer, and it is more preferable to impregnate silicon with silica. As a suitable usage amount, 1 to 10 weight% is suitable. It can be used by adding or subtracting as needed for proper air volume control.

Moreover, conventional cellulose, polyvinyl alcohol, polysaccharide, aluminum magnesium silicate, etc. can be used as a thickener. However, such combinations require very careful attention.If these combinations are not suitable, they may cause cracks due to shrinkage of polymers, lack of horizontality, poor packaging properties due to excessive flowability due to lack of thixotropy, and durability. It can significantly reduce.

Therefore, preferably, aluminum magnesium silicate is used to impart thixotropy to suppress bleeding generated in concrete production and to secure a homogeneous phase of concrete, thereby preventing cracking due to partial stress caused by the reaction of cement. do. Suitable amount of 1 to 10% by weight is suitable and it is good to add or subtract as needed to secure thixotropy.

(A) Calcium aluminate or amorphous hydroxide in the second admixture is a strong condensation promoter and can usually make Portland cement into fast cement at about 10% by weight of Portland cement. However, in order to control the setting time, an appropriate amount of gluconate may be used here. As a suitable usage amount, 50 to 90 weight% in a 2nd admixture is suitable. If less than 50% by weight, the hardening time of the concrete is not suitable for repair, and if it exceeds 90% by weight it is difficult to use as a sharp phenomena.

In addition, the amorphous aluminum hydroxide or aluminate metal salt of (b) is used as a coagulant for shortening the curing time of calcium aluminate, and when used, it is used to shorten the curing time at low temperatures such as winter season or to induce rapid curing. do. Suitable amounts of 1 to 50% by weight are suitable, and preferably 10 to 20% by weight. If it is less than 1% by weight, the performance as a coagulant is poor, and if it exceeds 20% by weight, it is difficult to control the setting time.

When the second admixture is mixed at an appropriate composition ratio, and when using about 8 to 15% by weight when preparing ready-mixed concrete, it is possible to prepare a ready-mix polymer concrete that can maintain workability for about 1 hour to 2 hours.

If rapid curing is not necessary, polymer concrete for general curing can be made without using a second admixture.

When the first and second admixtures of the present invention are used in ready-mixed concrete, the first admixture is preferably used in an amount of about 7 to 13 wt% based on the total weight of concrete after manufacture, and the second admixture is the weight of the total concrete. About 8 to 15 wt%. The method of adding the admixture may be used directly in the mixer of the ready-mixed concrete factory or in the ready-mixed truck for the ready-mixed concrete. However, when used directly in the ready-mixed concrete truck, the drum of the mixer truck should be rotated for about 3 to 10 minutes, preferably about 5 minutes, so that the first admixture and the second admixture are sufficiently mixed with concrete.

In addition, the present invention may exhibit slightly different behavior depending on the type of cement. This is because the behavior of medium heat cement, low heat cement and the like is different from the normal cement, it is possible to obtain appropriate performance by using the amount used. But the most preferred cement is usually cement. In addition, the size of the gravel can be used differently depending on the intended use and about 1/3 of the thickness of the concrete or mortar used is preferred.

Hereinafter, the present invention will be described in more detail with reference to Examples.

These examples are only for illustrating the present invention in more detail, and the scope of the present invention is not limited by these examples in accordance with the gist of the present invention to those skilled in the art. Will be self-evident.

Example

Example  1: ready Mix  With the ability to suppress alkali aggregate reactions that can be produced in concrete Low elasticity Polymer  concrete Miscible  Manufacturing method

To prepare a low-elastic polymer concrete admixture having the ability to suppress the alkali aggregate reaction that can be produced in ready-mixed concrete in the composition shown in Table 1 below.

ingredient First mixed fire Second mixed fire Content (% by weight) Content (% by weight) Powder redispersible resin 50 0 Powdered Carbonic Acid Dispersant 10 10 Lithium nitrate 20 0 Antifoam 5 0 Polysaccharides 5 0 Calcium Aluminate 10 80 Amorphous aluminum hydroxide 0 10 Sum 100 100

Among the components of Table 1, the powder redispersible resin was used DM-200 EVA powder redispersible resin of Houcst, Germany, Melflux 2651F of BASF, Germany was used as the powder carboxylic acid-based dispersant In the case of lithium nitrate, a first-class reagent of Aldrich, USA was used, Lumitene EL of BASF, Germany was used, Welan gum was used as polysaccharide, and commercially available Chinese products were used for calcium aluminate. Lastly, BZ 111, a company made in Germany, was used as amorphous aluminum hydroxide.

After preparing the first admixture and the second admixture with the above composition, 7% by weight of the first admixture and 8% by weight of the second admixture with respect to the weight of the cement were manually added to the ready-made ready-mixed concrete. Mixing by rotating the drum in a truck for minutes allowed to obtain low-elastic polymer concrete with the ability to inhibit alkaline aggregate reactions that can be produced in ready-mixed concrete.

Experimental Example

Low-elastic polymer concrete performance (breathability, compressive strength, compressive shear adhesion strength, breakage of the upper surface during breakage and waterproofness) with the suppression of alkali aggregate reaction that can be produced in the ready-mixed concrete of the present invention prepared in Example 1 In order to confirm, the following experiment was performed, as shown in Table 2 below.

Here, the control is concrete (Comparative Example 1) and concrete including an acrylic emulsion (Comparative Example 2) without using an additive.

cement water sand Pebble additive Example 1 30 20 20.5 25 4.5 Comparative Example 1 30 20 25 25 0 Comparative Example 2 30 20 22 25 3

Note: The content unit of the component is weight percent.

Experimental Example  1: Compressive strength measurement

Using a concrete of Example 1 and the concrete of Comparative Examples 1 and 2 to prepare a 10m x 10 cm 2 round mold, and curing for 28 days, the compressive strength was measured. The compressive strength was measured before and after freeze thawing.

In addition, the compressive strength after the wet repetition was carried out according to the KSF 2456 "Compressive Strength Test Method for Hydraulic Cement Concrete", and the repetition of freezing and thawing was measured after 200 cycles repetition based on KSF 2560 "Chemical Admixture for Concrete". The compressive strength before and after freeze thawing was compared. The compressive strength is a load value with respect to the cross-sectional area. The larger the value, the better the performance.

Experimental Example  2: Measurement of compressive shear bond strength

Using the concrete of Example 1 and Comparative Examples 1 and 2 on a 200 x 200 x 10 cm 3 concrete specimen, the upper part was laid in concrete and cured for 28 days, followed by ASTM C 882 (Test method for bond strength of epoxy-resin). The compressive shear bond strength to concrete of the present invention was measured by systems for concrete, American Society for Testing and Materials .

In addition, the observation of the change of the adhered part after repeated wet wetting was performed by the freeze-thaw test method (KSF 2456, chemically mixed admixture for concrete), and after 200 cycles of freezing and thawing, the compressive shear adhesive strength was measured and repaired before and after freeze-thawing. The adhesive strength of the cotton was compared. Calculation formula of the compressive shear adhesive strength is as shown in Equation 1 below, the larger the value is the better the performance.

Compressive shear bond strength = vertical load (kgf) / cross section of sample (㎠)

Experimental Example  3: expansion ratio by alkali latent reaction test method of aggregate

Example 1 Concrete and the concrete of Comparative Examples 1 and 2 were measured for expansion rate according to the method according to ASTM C 1260 (mortar method).

Experimental Example  4: Comparison of Relative Absorption Ratio

 Using the concrete of Example 1, and the concrete of Comparative Examples 1 and 2 to produce a circular mold of 10φx 10 cm 2 and cured for 28 days, and dried until no change in weight at 50 ℃ 24 hours, this After the specimen was completely immersed in water for 72 hours, the weight change after 72 hours and the weight after 72 hours were measured. The water resistance was measured by calculating the relative absorption ratio by dividing the difference between these two values as the absorbed amount of the specimen based on the absorbed value of Comparative Example 1.

The results of Experimental Examples 1 to 4 are shown in Table 3 below.

division Slump over time (after 60 minutes) Compression shear adhesive strength (Kgf / ㎠, 28 days) Compressive strength of mortar or concrete (Kgf / ㎠) Expansion rate (%) Relative Absorption Ratio (%) cm Before freeze thawing After freeze thawing Before freeze thawing After freeze thawing 3 days 7 days 28 days Example 1 2 16 15 413 434 446 435 0.2 22 Comparative Example 1 10 7 0 178 235 304 208 0.01 100 Comparative Example 2 16 15 13 256 345 412 376 0.05 34

As shown in Table 3, when the present invention additive of Example 1 was added, it was much better than Comparative Examples 1 and 2. The change in slump over time, which is a property before hardening, is much better than the existing polymer concrete, so it is not difficult to use when used in ready-mixed concrete, and the compressive strength and absorption ratio are also superior to acrylic polymer concrete. In addition, the expansion ratio by the mortar method is also measured to be low and can be easily prepared by adding polymer concrete to the ready-mixed concrete.

Claims (7)

delete (A) redispersible powder polymer resin, (B) polycarboxylic acid powder dispersant, (C) lithium hydroxide, lithium nitrate or lithium nitrite, (D) antifoaming agent and (E) cellulose, polyvinyl alcohol, poly A first admixture comprising at least one of a thickener consisting of saccharide and aluminum magnesium silicate, adding a second admixture comprising (a) calcium aluminate or amorphous hydroxide and (b) amorphous aluminum hydroxide or aluminate metal salt to a concrete consisting of cement, sand, gravel and water, and Method for producing a low-elastic polymer concrete admixture for the suppression of alkali aggregate reaction comprising the step of mixing the first admixture, the second admixture and the concrete. According to claim 2, wherein the first admixture is (A) 20 to 70% by weight redispersible powder polymer resin, (B) 5 to 25% by weight polycarboxylic acid-based powder dispersant, (C) lithium hydroxide, lithium nitrite 10 to 25% by weight of latent or lithium nitrite, (D) 1 to 10% by weight of antifoam, and (E) 1 to 10% by weight of thickener consisting of cellulose, polyvinyl alcohol, polysaccharide and aluminum magnesium silicate. A low elastic polymer concrete admixture for inhibiting alkali aggregate reaction. 3. The alkali according to claim 2, wherein the second admixture comprises a) 50 to 90% by weight of calcium aluminate or amorphous hydroxide and (b) 1 to 50% by weight of amorphous aluminum hydroxide or aluminate metal salt. Low elastic polymer concrete admixture for suppressing aggregate reaction. The method of claim 3, wherein the first admixture comprises 7 to 13% by weight based on the weight of the cement. The method of claim 4, wherein the second admixture comprises 8 to 15 wt% based on the weight of the cement. 3. The method of claim 2, wherein the concrete is ready mixed concrete.