KR101723345B1 - Water proof admixtures composition for concrete and Method for constructing an concrete structure using the same - Google Patents

Abstract

The present invention relates to a water proof composition for concrete. More specifically, the water proof composition for concrete is added with a material used for manufacturing concrete (cement, gravel, sand, water and an admixture for concrete), thereby improving water tightness of a concrete hardening body, which is a final product, improving resistance against various chemical components causing degradation of concrete, and inhibiting crack formation of a concrete structure by reducing drying shrinkage.

Description

TECHNICAL FIELD The present invention relates to a waterproof composition for concrete and a method for constructing a concrete structure using the waterproof admixture composition.

The present invention relates to a waterproofing composition for concrete, which is added together with the materials (cement, gravel, sand, water, and admixture for concrete) used in concrete production in more detail, thereby improving the watertightness of the final product, The present invention relates to a waterproofing composition for concrete, which improves the resistance to various chemical components that cause deterioration of concrete and reduces the drying shrinkage, thereby suppressing cracking of the concrete structure.

In order to ensure the quality and workability required for the manufacturing process and the casting process, excess water other than the mixed water required for hardening the cement is used. However, due to the excessive amount of water used in the concrete, It has porosity. In addition, since the concrete structure is exposed to various physical and chemical conditions according to the external environment, the cracks are continuously generated, and the durability is greatly reduced due to the deterioration.

The cracks generated in the concrete structure significantly reduce the water resistance and promote the movement of various chemicals from the outside to the inside of the concrete, thus greatly reducing the durability of the concrete.

In order to overcome these problems of concrete structures, various types of waterproofing works have been applied to concrete structures currently used. However, as a general method of forming a waterproof layer on the concrete surface, there is always a satisfactory result in various external environments It can not be shown.

Therefore, it is preferable to improve the waterproof performance of the concrete itself by improving the watertightness of the entire concrete structure rather than to improve the waterproof performance of the concrete surface. At the same time, it is desirable to suppress the drying shrinkage of the concrete to suppress the generation of cracks effective. In addition, in order to achieve the above object, the performance of the concrete itself should not be deteriorated even if the waterproofing material is included in various materials used for the concrete.

Conventional related arts have problems such as deterioration of strength of concrete or inappropriate mixing with concrete material.

In order to solve the above problems, researches for using sulfur as a construction material are under way and various research results have been published. In recent years, sulfur concrete has been developed to improve waterproof, stability and workability by using sulfur with cement.

(WO2012121432A1) is used instead of sulfur as it is because of odor, handling or safety problems, but the limit due to economical and time-consuming processes such as the processes required for reforming is still not overcome.

Therefore, there is a need for a new waterproofing composition for concrete to solve the above problems.

Korean Patent Laid-Open No. 10-2014-0004990 "Coal material sulfur polymer cement concrete made from coal ash and sulfur" Korean Patent No. 10-1419445 entitled "High-density and high-density mortar composition for waterproofing and repairing and reinforcing concrete structures, and waterproofing and repairing and reinforcing seismic resistant methods using the same,

Accordingly, in order to solve the above-mentioned problems of the concrete structure, the present invention has been made to solve the above-mentioned problems of the concrete structure by improving the watertightness of the concrete to secure waterproof property, to provide the expandability to the concrete, to reduce the drying shrinkage to suppress cracking, Which is excellent in affinity with various components and materials used in concrete.

In order to solve the above problems,

The present invention provides a waterproofing composition for concrete, which comprises 1 to 3 parts by weight of glycerin per 100 parts by weight of a sulfuric aqueous solution obtained by reacting a sulfuric acid aqueous solution containing potassium hydroxide, sodium hydroxide and calcium hydroxide with a sulfuric acid aqueous solution under high temperature and high pressure do.

At this time, the waterproofing composition for concrete may be a liquid.

At this time, the sulfuric aqueous solution is mixed with a strong basic aqueous solution containing 18 to 27 parts by weight of sulfur powder, 9 to 13 parts by weight of potassium hydroxide, 10 to 18 parts by weight of sodium hydroxide, 6 to 13 parts by weight of calcium hydroxide and 30 to 50 parts by weight of water Followed by reaction at 200 to 300 ° C and 1.5 to 3 atm.

At this time, the waterproofing composition for concrete preferably comprises 1 to 2 parts by weight of terphenyl oil, 1 to 2 parts by weight of sodium fluoride, 1 to 2 parts by weight of sodium hydrogen fluoride, 1 to 2 parts by weight of sodium silicate, 20 to 40 parts by weight.

In addition,

A method of constructing a concrete structure comprising the steps of mixing cement, water and aggregate,

And a concrete waterproofing composition for concrete is added to the mixing step.

The waterproofing composition for concrete according to the present invention not only improves the watertightness of the concrete to improve the waterproof property but also has an excellent compressive strength to reduce the drying shrinkage thereby to suppress cracking and to improve the compatibility with various components and materials used for concrete production This has an excellent effect.

Hereinafter, the present invention will be described in detail.

The present invention provides a waterproofing composition for concrete capable of suppressing the generation of cracks by improving the watertightness to improve the waterproof property and also providing the concrete with sufficient expansibility to reduce drying shrinkage.

The inventors of the present invention conducted research to produce a waterproofing composition having little smell unique to sulfur, and excellent handling and stability. The waterproof composition prepared in the form of a liquid was prepared by melting sulfur in an aqueous solution state . Sulfur produced in liquid form can be easily added at the time of concrete mixing and can be mixed evenly and quickly into concrete formulations.

Specifically, the waterproofing composition for concrete according to the present invention is prepared by first preparing a sulfuric aqueous solution obtained by reacting sulfuric acid powder with a strong base aqueous solution containing potassium hydroxide, sodium hydroxide and calcium hydroxide under high temperature and high pressure, and mixing glycerin at a predetermined ratio .

The sulfur powder may be a natural sulfur powder or a modified sulfur powder, and is not particularly limited in the present invention, and natural sulfur powder is preferably used.

Wherein the strong base aqueous solution is for completely melting the sulfur powder, wherein the sulfur aqueous solution is prepared by mixing 9 to 13 parts by weight of potassium hydroxide, 10 to 18 parts by weight of sodium hydroxide, 6 to 13 parts by weight of calcium hydroxide, And 30 to 50 parts by weight of an aqueous solution of a strong base. When the amount of the strong base aqueous solution is less than the above range, the sulfur may not be properly melted. When the amount of the strong base aqueous solution is more than the above range, cracking of the concrete may be difficult to suppress. Therefore, an appropriate amount in the above range can be used.

At this time, in order to sufficiently dissolve the sulfur powder, the reaction is carried out under high temperature and high pressure, not at room temperature and normal pressure. The temperature is 200 to 300 DEG C and the pressure is 1.5 to 3 atm for 2 to 4 hours. When the temperature is outside these ranges, the sulfur powder is not sufficiently dissolved.

The sulfuric acid aqueous solution obtained after the reaction is used as it is or after filtration to remove impurities.

In particular, the waterproof composition of the present invention can be prepared by mixing the sulfuric aqueous solution prepared above with glycerin.

Glycerin is in a liquid state, and even if it is added, it is possible to easily prepare a waterproof composition in a liquid state.

Glycerin is a colorless and odorless liquid for preventing the separation of concrete from materials. It has a very high viscosity and plays a role to prevent material separation and improve workability when mixed with concrete. 3 parts by weight.

The mixing of the sulfur aqueous solution and glycerin is not particularly limited, and mixing using various known mixing devices is possible.

Further, the waterproofing composition for concrete of the present invention may further include an additive to further improve waterproof property, dispersion stability, and the like.

1 to 2 parts by weight of terfenafine, 1 to 2 parts by weight of sodium fluoride, 1 to 2 parts by weight of sodium hydrogen fluoride, 1 to 2 parts by weight of sodium silicate, and 20 to 40 parts by weight of water are added to 100 parts by weight of the aqueous sulfuric acid solution May be further included.

The terphenyl oil is used to improve the mutual bonding force of the concrete mixture, and may be added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the aqueous sulfur solution.

The fluorinated Ca ^{2 +} is sodium, hydrogen fluoride, sodium is eluted during cement hydration, Mg ^{2 +,} Na ⁺ or K ⁺ ion and the reaction scarcely-soluble metal compounds, such as CaF _2, MgF _2, NaF or KF, etc. So as to absorb the heat of hydration and to prevent the generation of pores in the concrete due to the heat of hydration, thereby improving the strength of the concrete. The sodium fluoride and the sodium fluoride may each be contained in an amount of 1 to 2 parts by weight based on 100 parts by weight of the aqueous sulfuric solution.

The sodium silicate (water glass = Na ₂ O.nSiO ₂ .xH ₂ O, n = 2 to 4) is formed in the hydration process of the calcium silicate phase (3CaO.SiO ₂ , 2CaO.SiO ₂ ) (CaO-SiO ₂ -H ₂ O) is generated or directly produced by the calcium hydroxide by the calcium hydroxide to thereby significantly improve the watertightness of the concrete. In particular, it inhibits the growth of calcium hydroxide crystals and improves the interfacial properties between aggregate and cement, thereby improving the durability of concrete and enhancing strength. The CSH gel produced by this process forms a dense inner structure of the concrete and greatly improves water tightness. The sodium silicate may be added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the aqueous sulfuric acid solution.

The obtained waterproofing composition for concrete has a viscosity similar to that of water, has a transparent yellow to orange color, and has a different color concentration depending on the viscosity.

The waterproofing composition for concrete according to the present invention is prepared in the form of a liquid, and can be used preferably in the production of a concrete structure by diluting it by concentration. The composition may be diluted 200 to 2000 times with water.

The concrete structure is composed of cement and aggregate as basic constituents. Various additives can be used herein. The cement is not particularly limited in the present invention. The cement is not limited to Portland cement, weather-hardening cement, hydraulic cement, (Cement), white cement, expanded vermiculite cement, expansive hydraulic cement, masonry cement, cold rolled cement, fly ash cement, fly ash cement, Portland cement, low temperature cement, Cement, antistatic cement, and oil-based cement.

Aggregates can be divided into sand and coarse aggregate. Small aggregate particles such as sand are referred to as fine aggregates or fine aggregates, and relatively large aggregates are sometimes referred to as coarse aggregates or coarse aggregates. Aggregate refers to aggregates containing all of these fine aggregates or coarse aggregates, and sandy aggregates such as fine aggregates.

In addition, the aggregate may be various kinds of sand, gravel, and crushed stone as well as industrial waste, fly ash, silica sand, silica, quartz, clay, and glass powder that can be recycled

In addition to the above composition, various compositions used in the production of the concrete structure may further be included. For example, a chemical admixture for special use such as fly ash, slag, silica fume, metakaolin and water-insoluble admixture, thickener, retarder, and quick-setting agent may be further included.

At this time, the amount of the waterproofing composition for concrete proposed in the present invention may be 0.01 to 0.3% by weight, preferably 0.21% by weight, based on the cement content. For example, when 1,000 kg of cement is used, it is calculated as 'cement weight * 0.21 wt%', and the waterproof composition for concrete can be used at 2.1 kg.

Depending on the working environment, the waterproof concrete composition may be added immediately before use or may be mixed with ready mixed concrete.

In summary, when the concrete structure is manufactured by using the waterproofing composition for concrete proposed in the present invention, there is the following advantage.

First, concrete not only improves the watertightness but also inhibits cracking due to drying shrinkage.

Second, excellent structural stability can be achieved due to excellent waterproofing and strength even when used in building structures exposed to the ground as well as underground buildings where waterproofing is particularly required.

Thirdly, it is manufactured in a liquid state and can be easily added when mixing cement, sand and gravel, so that it is convenient to use.

Fourth, it is easy to calculate the capacity relative to cement, and it is possible to manufacture the cement according to the concentration during the manufacturing process.

The waterproofing composition for concrete according to the present invention can be used not only by being directly mixed with the basic material of concrete (cement, gravel, sand, water, concrete), but also by using fly ash, It can be stably used together with a chemical admixture for special purpose such as slag, silica fume, meta kaolin and water-insoluble admixture, thickener, retarder, and quick-setting agent. Also, it is possible to mix not only the composition according to the present invention during the concrete production process, but also mix the composition of the present invention in the concrete.

EXAMPLES, COMPARATIVE EXAMPLES AND EXPERIMENTAL EXAMPLES will be described below to help understand the effects of the present invention. It should be noted, however, that the following description is only an example of the contents and effects of the present invention, and the scope and effect of the present invention are not limited thereto.

< Example  1>

25 parts by weight of sulfur, 10 parts by weight of potassium hydroxide, 15 parts by weight of sodium hydroxide, 10 parts by weight of calcium hydroxide and 40 parts by weight of water were mixed, and the mixture was heated to 100 ° C to 250 ° C and heated at 2.5 atm for 3 hours. Thereafter, the mixture was cooled to 130 DEG C, stirred for 60 minutes, and cooled to room temperature.

To the reaction mixture, 2 parts by weight of glycerin, 1.5 parts by weight of terpine oil, 1 part by weight of sodium fluoride, 1 part by weight of sodium hydrogen fluoride and 1 part by weight of sodium silicate were added and stirred for 5 minutes. Then, 32 parts by weight of water was added and stirred, Waterproofing composition was prepared.

Then, the waterproofing composition for concrete was added to 0.21 wt% of the cement weight to prepare concrete according to the formulation shown in Table 1 below.

< Comparative Example  1>

The concrete shown in Table 1 below was prepared without adding the waterproofing composition for concrete of Example 1 described above.

< Comparative Example  2>

A waterproofing composition not containing only glycerin was added to the waterproofing composition for concrete of Example 1 to prepare concrete according to the formulation shown in Table 1 below.

< Comparative Example  3>

A concrete waterproofing composition for concrete in place of the waterproofing composition for concrete in Example 1 was added in an appropriate amount to prepare concrete according to the formulation shown in Table 1 below.

Unit (kg / m ³ ) water cement Fine aggregate
(sand) Coarse aggregate
(Pebble) Waterproofing composition for concrete
(Cement * 0.21% by weight) Waterproofing composition for concrete
(Cement * 0.21% by weight, without glycerin) Commercial waterproofing agent Example 1 189 300 761 975 0.63 - - Comparative Example 1 189 300 761 975 - - - Comparative Example 2 189 300 761 975 - 0.63 - Comparative Example 3 189 300 761 975 - - 1.5

< Experimental Example  1> Concrete Properties Analysis Example  One, Comparative Example  One)

In order to evaluate the performance of the waterproofing composition for concrete prepared in Example 1, the concrete of Example 1 including the waterproofing composition for concrete of the present invention and the concrete of Comparative Example 1 which did not include the composition The compressive strength ratios (7 days, 28 days), water absorption coefficient ratios, permeability ratios and length change ratios (7 days, 28 days) were measured twice according to KS F 4926 "Waterproofing for concrete admixture". The results are shown in Table 2 below.

The values of the compressive strength ratio, the water absorption strength ratio, and the permeability ratio of the items of Table 2 indicate 'the value of Example 1 / the value of Comparative Example 1', and the rate of change in length was 7 days and 28 days after the concrete of Example 1 And the rate of change of length due to drying shrinkage.

division Result of 1 time Results of 2 times Average result value Compressive strength ratio (7 days) 1.06 1.1 1.08 Compressive strength ratio (28 days) 1.03 1.0 1.015 Water absorption intensity ratio 0.57 0.6 0.585 Pitch ratio 0.64 0.6 0.62 Length change rate (7 days,%) 0.05 0.05 0.05 Length change rate (28 days,%) 0.05 0.06 0.055

< Experimental Example  2> Concrete Properties Analysis Example  One, Comparative Example  2)

In order to evaluate the performance of the waterproofing composition for concrete prepared in Example 1, the concrete of Example 1 including the waterproofing composition for concrete of the present invention and the waterproofing composition for concrete prepared without containing only glycerin The compressive strength ratio (7 days, 28 days), water absorption coefficient ratio, permeability ratio and length change rate (7 days, 28 days) of the prepared concrete of Comparative Example 2 were measured twice according to KS F 4926 " Respectively. The results are shown in Table 3 below.

division Result of 1 time Results of 2 times Average result value Compressive strength ratio (7 days) 1.03 1.04 1.035 Compressive strength ratio (28 days) 1.01 1.0 1.005 Water absorption intensity ratio 0.60 0.64 0.62 Pitch ratio 0.65 0.64 0.645

< Experimental Example  3> Concrete Properties Analysis Example  One, Comparative Example  3)

In order to evaluate the performance of the waterproofing composition for concrete prepared in Example 1, the concrete of Example 1 and the concrete of Comparative Example 3, which were manufactured using the waterproofing composition of the present invention, The compressive strength ratios (7 days, 28 days), water absorption coefficient ratios, permeability ratios and length change ratios (7 days, 28 days) were measured twice according to KS F 4926 "Waterproofing for concrete admixture". The results are shown in Table 4 below.

division Result of 1 time Results of 2 times Average result value Compressive strength ratio (7 days) 1.03 1.02 1.025 Compressive strength ratio (28 days) 1.02 1.02 1.02 Water absorption intensity ratio 0.63 0.62 0.625 Pitch ratio 0.74 0.78 0.76

As shown in Tables 2 to 4, the concrete prepared with the waterproofing composition for concrete of the present invention had a high compressive strength ratio (7 days, 28 days) as compared with Comparative Examples 1 to 3, And the water-absorbing strength ratio and the water permeability ratio are low, so that the water-tightness is high and the water-proof property is excellent. Also, since the rate of change in length (7 days, 28 days) is also low, the drying shrinkage of the concrete is not so severe, and cracking of the concrete can be suppressed.

Claims (5)

A strong base aqueous solution containing 9 to 13 parts by weight of potassium hydroxide, 10 to 18 parts by weight of sodium hydroxide, 6 to 13 parts by weight of calcium hydroxide and 30 to 50 parts by weight of water is mixed with 18 to 27 parts by weight of sulfur powder, And 1 to 3 parts by weight of glycerin relative to 100 parts by weight of an aqueous sulfuric acid solution produced by reacting at a pressure of 1.5 to 3 atm. The method according to claim 1,
Wherein the waterproofing composition for concrete is a liquid. delete The method according to claim 1,
The waterproofing composition for concrete is prepared by mixing 1 to 2 parts by weight of terpine oil, 1 to 2 parts by weight of sodium fluoride, 1 to 2 parts by weight of sodium hydrogen fluoride, 1 to 2 parts by weight of sodium silicate, And 40 parts by weight of water. A method of constructing a concrete structure comprising the steps of mixing cement, water and aggregate,
Wherein the waterproofing composition for concrete according to any one of claims 1, 2, and 4 is added to the mixing step.