KR101946417B1 - High durability concrete composition with excellent fluidity and long-term durability - Google Patents

Abstract

Disclosed is a high-durability concrete composition enhanced in fluidity and long-term durability applicable to reinforced concrete structures, including bridge decks, which are required to have durability performance by being exposed to corrosion conditions of reinforcing steel or deterioration of concrete, and structural repairing and reinforcing materials. The high-durability concrete composition enhanced in fluidity and long-term durability according to the present invention comprises: 15-25 wt% of cement; 30-40 wt% of fine aggregate; 35-45 wt% of coarse aggregate; 4-10 wt% of water; 1-6 wt% of a polymer admixture. The polymer admixture includes an SB polymer emulsion, a polycarboxylic acid compound; a preserver, and an anionic surfactant.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-durability concrete composition having improved fluidity and long-term durability,

The present invention relates to a high-durability concrete composition having improved fluidity and long-term durability, and more particularly, to a reinforced concrete structure, a structure repairing and reinforcing material including a bridge deck, which is required to have durability by being exposed to a corrosion- The present invention relates to a high-durability concrete composition having improved fluidity and long-term durability.

Generally, a concrete admixture is added with a chemical admixture such as a fluidizing agent and a water reducing agent to ensure fluidity, workability and the like, and at the same time, hardness is secured by controlling the water content of the concrete composition.

However, since the conventional chemical admixture only affects the properties of the unhardened concrete, improvement in durability such as deterioration of the concrete structure exposed to various corrosive environments and freeze-thaw resistance and salt resistance to improve the common life can not be expected There are disadvantages.

In order to improve the long-term durability of concrete, polymer-modified concrete containing various polymer modifiers such as latex and EVA resin has been developed. However, since expensive polymer modifier is used as an admixture for securing the required quality of concrete, As the cost increases due to the increase of the construction cost, it is disadvantageous to economical efficiency and it is used as an extremely limited use as the surface layer packing material of the bridge deck.

A related prior art document is Korean Patent Laid-Open Publication No. 10-2001-0070730 (published on July 27, 2001), which discloses a specific porous concrete composition having high strength and durability.

It is an object of the present invention to provide a high-durability concrete composition improved in flowability and long-term durability applicable to reinforced concrete structures, structure repairing and reinforcing materials, including bridge decks, which are required to have durability by being exposed to the environment of steel corrosion or concrete deterioration will be.

To achieve the above object, the present invention provides a highly durable concrete composition having improved fluidity and long-term durability, comprising 15 to 25 wt% of cement, 30 to 40 wt% of fine aggregate, 35 to 45 wt% of coarse aggregate, To 10% by weight of a polymeric admixture and 1 to 6% by weight of a polymer admixture, wherein the polymer admixture comprises an SB polymer emulsion, a polycarboxylic acid-based compound, a surfactant, and an anionic surfactant.

Wherein the polymeric admixture comprises 70 to 85% by weight of SB polymer emulsion, 5 to 15% by weight of polycarboxylic acid compound, 1 to 5% by weight of a preservative and 0.1 to 3% by weight of an anionic surfactant .

The above-mentioned preservative may include at least one selected from maleic anhydride, polyethylene glycol, methacrylic acid, methyl methacrylate, acrylic acid and acrylamide.

The anionic surfactant includes at least one selected from carboxylic acid salts, dodecylbenzenesulfonic acid salts, sodium acid salts, alkylnaphthalene derivatives, chlorobenzene derivatives, alkylaryl sulfonates, higher fatty acid alkali metal salts and alkylbenzenesulfonic acid salts can do.

In addition, the high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention may further include blast furnace slag fine powder.

The blast furnace slag powder is preferably added in an amount of 20 to 50 parts by weight based on 100 parts by weight of the cement.

Also, the high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention may further include at least one selected from a defoaming agent and a shrinkage reducing agent.

The high durability concrete composition having improved fluidity and long-term durability according to the present invention can improve the fluidity and retention of the concrete composition by adding a polymer admixture and reduce the unit yield and increase the strength through the chemical reaction of the polymer admixture during the cement hydration And durability performance such as reduction in crack generation, freeze-thaw resistance, salt resistance, abrasion resistance and the like can be improved to ensure long-term durability.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

High durability concrete composition

The high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention includes cement, fine aggregate, coarse aggregate, water and polymer admixture.

Particularly, a polymer admixture is one obtained by adding a polycarboxylic acid-based compound, a surfactant, and an anionic surfactant to an SB polymer emulsion.

This polymer admixture improves the flowability and retention of unhardened concrete, and improves strength and cracking through polymer modification of concrete and improves durability such as salt penetration resistance, abrasion resistance, and scaling resistance .

Specifically, the high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention includes 15 to 25 wt% of cement, 30 to 40 wt% of fine aggregate, 35 to 45 wt% of coarse aggregate, 4 to 10 wt % And 1 to 6% by weight of a polymer admixture.

Hereinafter, each composition material of the high-durability concrete composition having improved fluidity and durability according to the embodiment of the present invention, the composition ratio thereof, and the role of each material will be described in detail.

The cement may be at least one selected from ordinary Portland cement, crude steel Portland cement, rough steel Portland cement, medium heat Portland cement, refractory Portland cement, white Portland cement, and ultra rapid cement. At this time, it is more preferable to use the ordinary portland cement specified in KS so that the concrete can be obtained economically and stably.

The cement is preferably added at a content ratio of 15 to 25% by weight of the total weight of the concrete composition.

Fine aggregate is commonly referred to as sand, and both fine and rough aggregates can be used. At this time, it is preferable that the fine aggregate is made of a material which substantially passes through the No. 4 sieve (ASTM C 125, 4.75 mm). The coarse aggregate may include at least one selected from the materials that remain predominantly in the No. 4 sieve (ASTM C 125, 4.75 mm), such as silica sand, quartz, marble, granite, limestone, calcite, feldspar, .

The residual aggregate is preferably added at a content ratio of 30 to 40% by weight in the total weight of the concrete composition. If the added amount of the aggregate aggregate is less than 30% by weight of the total weight of the concrete composition, it may be difficult to secure the fluidity of the concrete. On the other hand, when the added amount of the fine aggregate exceeds 40 wt% of the total weight of the concrete composition, it may be difficult to secure the strength.

Coarse aggregates are also commonly referred to as gravels and are not limited to the types commonly used in the art. It is preferable to use crumbly aggregate or natural aggregate as the coarse aggregate, and it is preferable to use KS F 2502 or KS F 2527. The coarse aggregate is preferably added at a content ratio of 35 to 45% by weight of the total weight of the concrete composition.

Water may be used without limitation as long as it meets the criteria specified in KS, but it is recommended to use purified water with no impurities. Such water may be added at a content ratio of 4 to 10% by weight of the total weight of the concrete composition.

The polymer admixture has the role of improving fluidity and retention of unhardened concrete by decreasing the unit water quantity and the action of fine air stream when added to the concrete composition, improving the material separation resistance and reducing the bleeding.

In addition, the polymer admixture improves the flowability and retention of the unhardened concrete composition and improves the internal pore structure by polymer reforming of the concrete, thereby reducing the strength enhancement and the occurrence of cracks, and the salt penetration resistance, abrasion resistance and scaling resistance Thereby improving durability performance.

The polymer admixture is preferably added at a content ratio of 1 to 6% by weight of the total weight of the concrete composition. If the addition amount of the polymer admixture is less than 1% by weight of the total weight of the concrete composition, the amount of the polymer admixture is too small to improve the performance of the concrete composition. On the other hand, when the addition amount of the polymer admixture exceeds 6 wt% of the total weight of the concrete composition, good physical properties can be obtained in workability, mechanical properties, etc. However, , Which is undesirable.

Specifically, the polymer admixture comprises 70 to 85% by weight of an SB polymer emulsion, 5 to 15% by weight of a polycarboxylic acid compound, 1 to 5% by weight of a preservative and 0.1 to 3% by weight of an anionic surfactant .

The styrene-butadiene polymer emulsion is added to improve the physical properties of the concrete. It improves the internal pore structure of the concrete through the polymer reforming reaction and plays a role of suppressing cracking and improving durability.

The SB polymer emulsion is preferably added at a content ratio of 70 to 85% by weight of the total weight of the polymer admixture. If the addition amount of the SB polymer emulsion is less than 70% by weight of the total weight of the polymer admixture, it may be difficult to exhibit the above effects properly. On the other hand, when the addition amount of the SB polymer emulsion exceeds 85% by weight of the total weight of the polymer admixture, the physical properties such as workability and mechanical properties are improved, but the manufacturing cost can be increased due to overuse of the SB polymer emulsion, Can not do it.

Polycarboxylic acid-based compounds are added to improve strength and durability. The polycarboxylic acid-based compound is not particularly limited as long as it is derived from a monomer capable of polymerization or copolymerization with an unsaturated carboxylic acid monomer. For example, as the polycarboxylic acid-based compound, a copolymer of an unsaturated carboxylic acid monomer and styrene may be used, and Grace Chemicals Co., Ltd. may be used. "DARLEXSUPER 100, 200, 300, 1000" series manufactured by KAO Corporation and "MIGHTY 21WH" and "MIGHTY 3000" series manufactured by KAO Corporation are commercially available.

The polycarboxylic acid-based compound is preferably added at a content ratio of 1 to 5% by weight based on the total weight of the polymer admixture. When the addition amount of the polycarboxylic acid compound is less than 1% by weight of the total weight of the polymer admixture, the effect of improving the strength and durability is insignificant. On the contrary, when the addition amount of the polycarboxylic acid compound exceeds 5% by weight of the total weight of the polymer admixture, workability may be greatly lowered.

The preservative is added to the polymer admixture to improve shape retention. Such a preservative may include at least one selected from maleic anhydride, polyethylene glycol, methacrylic acid, methyl methacrylate, acrylic acid and acrylamide.

The preservative is preferably added at a content ratio of 1 to 5% by weight based on the total weight of the polymer admixture. When the amount of the preservative added is less than 1% by weight based on the total weight of the polymer admixture, the addition amount thereof is insufficient and it is difficult to improve the physical properties. On the contrary, when the amount of the preservative added exceeds 5% by weight of the total weight of the polymer admixture, the workability is greatly reduced.

The anionic surfactant plays a role of mixing and stabilizing the hydrophilic substance and the lipophilic substance. Examples of the anionic surfactant include at least one selected from the group consisting of carboxylic acid salts, dodecylbenzenesulfonic acid salts, sodium acid salts, alkylnaphthalene derivatives, chlorobenzene derivatives, alkylaryl sulfonates, higher fatty acid alkali metal salts and alkylbenzenesulfonic acid salts .

The anionic surfactant is preferably added at a content ratio of 0.1 to 3% by weight based on the total weight of the polymer admixture. When the addition amount of the anionic surfactant is less than 0.1% by weight of the total weight of the polymer admixture, the addition amount is insufficient and it is difficult to exhibit the effect of addition properly. Conversely, when the amount of the anionic surfactant added is less than 3% by weight of the total weight of the polymer admixture, the production cost is increased due to an increase in the amount of the anionic surfactant, which is quite expensive, which is not economical.

In addition, the high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention may further include blast furnace slag fine powder.

Blast furnace slag is finely pulverized wastes slag, which is a by-product of the pig iron manufacturing process, which increases the long-term strength of cement and increases the water-tightness and water-resistance. The blast furnace slag is preferably used in a powder of 1,000 to 10,000 cm 2 / g, more preferably 4,000 to 6,000 cm 2 / g, so that the strength of the concrete composition is not deteriorated while maintaining the flowability of the concrete composition. The fine blast furnace slag powder is preferably added in an amount of 20 to 50 parts by weight based on 100 parts by weight of the cement. When the added amount of the blast furnace slag powder is less than 20 parts by weight based on 100 parts by weight of the cement, the above effect is hardly exhibited properly. On the other hand, when the added amount of the blast furnace slag powder is more than 50 parts by weight based on 100 parts by weight of the cement, the fluidity and long-term durability may be lowered.

Also, the high-durability concrete composition having improved fluidity and long-term durability according to an embodiment of the present invention may further include at least one selected from a defoaming agent and a shrinkage reducing agent.

The antifoaming agent acts to remove the pores in the concrete composition to enhance the strength and durability of the concrete. The antifoaming agent is preferably added in an amount of 0.01 to 2% by weight based on the total weight of the concrete composition. As the defoaming agent, at least one selected from commonly known materials such as an alcohol defoaming agent, a silicone defoaming agent, a fatty acid defoaming agent, an oil defoaming agent, an ester defoaming agent, and an oxyalkylene defoaming agent may be used.

The shrinkage reducing agent serves to prevent cracking of the concrete composition. As the shrinkage reducing agent, for example, polyethylene glycol may be used.

The shrinkage reducing agent is preferably added in an amount of 0.1 to 3% by weight based on the total weight of the concrete composition. When the addition amount of the shrinkage reducing agent is less than 0.1% by weight of the total weight of the concrete composition, it is difficult to exhibit the crack preventing effect properly. On the contrary, when the addition amount of the shrinkage reducing agent exceeds 3% by weight of the total weight of the concrete composition, the viscosity increases and the workability may be lowered.

The high durability concrete composition having improved fluidity and long-term durability according to the embodiment of the present invention can improve the fluidity and retention of the concrete composition by adding a polymer admixture, while reducing the unit yield and improving the chemical properties of the polymer admixture Through the reaction, the durability performance such as strength enhancement and reduction of crack occurrence, freeze-thaw resistance, salt resistance and abrasion resistance can be improved and long-term durability performance can be ensured.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example  One

Mixed with 17.5 wt% of Portland cement, 33.4 wt% of residual aggregate, and 41.7 wt% of coarse aggregate, and further mixed with 6.05 wt% of water and 1.35 wt% of polymer admixture and further stirred for 5 minutes, A composition was prepared.

The polymer admixture was composed of 82 wt% of SB polymer emulsion, 12 wt% of DARLEX SUPER 100 as a polycarboxylic acid compound, 4 wt% of polyethylene glycol as a preservative, and 2 wt% of dodecylbenzenesulfonate as an anionic surfactant.

Example  2

17.5 wt% of ordinary Portland cement, 31.2 wt% of residual aggregate and 44 wt% of coarse aggregate were added to a forced mixer and stirred. Then, the mixture was further mixed with 5.9 wt% of water and 1.4 wt% of polymer admixture To prepare a concrete composition.

Example  3

Except that 16.7 wt% of Portland cement, 34.2 wt% of residual aggregate and 37.8 wt% of coarse aggregate were added to a forced mixer and stirred, and then 5.8 wt% of water and 5.5 wt% of polymer admixture were further mixed. The concrete composition was prepared in the same manner.

Example  4

16 wt% of Portland cement, 31.4 wt% of residual aggregate, and 40.2 wt% of coarse aggregate were added to a forced stirring mixer, and then mixed with 5.5 wt% of water, 1.5 wt% of polymer admixture and 5.4 wt% of blast furnace slag The concrete composition was prepared in the same manner as in Example 1. The results are shown in Table 1.

Example  5

17 wt% of Portland cement, 33 wt% of fine aggregate, and 41 wt% of coarse aggregate were charged into a forced stirring mixer and stirred. Then, 5.5 wt% of water, 1.5 wt% of polymer admixture, 0.5 wt% of silicone defoaming agent as defoaming agent, The concrete composition was prepared in the same manner as in Example 1 except that 1.5 wt% of glycol was further mixed.

Comparative Example  One

17.5% by weight of Portland cement, 35% by weight of fine aggregate, and 42.2% by weight of coarse aggregate were added to a forced stirring mixer and further mixed with 5.67% by weight of water and 0.13% by weight of high-performance AE water reducing agent. .

Table 1 shows the results of evaluation of physical properties of the concrete compositions prepared according to Examples 1 to 5 and Comparative Example 1. [

1) Compressive strength measurement

The test specimens were prepared by the method described in Korean Industrial Standard KS F 2403, 2405.

2) Crack resistance measurement

AASHTO PP 34 99 (crack resistance).

3) Durability performance <salt penetration resistance, freeze-thaw resistance, scaling resistance>

And evaluated according to the test standards of KS F 2711 (salt penetration resistance), KS F 2456 (freeze-thaw resistance) and SS 13 72 44 A method (scaling resistance).

[Table 1]

Referring to Table 1, it can be seen that Example 2 has a relatively higher compressive strength than Comparative Example 1, Examples 1 and 3 to 5, but has almost no difference.

In Comparative Example 1, cracks occurred at 10 days of age, but in Examples 1 to 5, cracks did not occur until the age of the test.

In the results of the salt penetration resistance test, Example 1 exhibited the lowest amount of permeation, and the following Examples 4, 5, 3, 2, and 1 were obtained.

In addition, in the results of the freeze-thaw resistance test, it can be seen that Examples 1 to 5 except for Comparative Example 1 are almost the same in the order of Examples 1 and 4> Examples 3 and 5> Example 2> Comparative Example 1.

As a result of the scaling resistance test, it is confirmed that Examples 1 to 5 have almost no difference and excellent scaling resistance as compared with Comparative Example 1.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

Claims (7)

Wherein the amount of the shrinkage reducing agent is in the range of 15 to 25 wt% of the cement, 30 to 40 wt% of the fine aggregate, 35 to 45 wt% of the coarse aggregate, 4 to 10 wt% of the water, 1 to 6 wt% of the polymer admixture, 3% by weight,
Polyethylene glycol is used as the shrinkage reducing agent, polyethylene glycol is used as the oil retaining agent, dodecylbenzene sulfonate is used as the anionic surfactant,
Wherein the polymer admixture comprises 82 to 85% by weight of SB polymer emulsion, 5 to 15% by weight of polycarboxylic acid compound, 1 to 5% by weight of a preservative and 0.1 to 3% by weight of an anionic surfactant,
Characterized in that the blast furnace slag fine powder further comprises 20 to 50 parts by weight based on 100 parts by weight of the cement, wherein the blast furnace slag fine powder has a powderity of 4,000 to 6,000 cm &lt; 2 &gt; / g. By weight. delete delete delete delete delete delete