KR101158302B1 - Latex modified concrete composition containing by-product of steel and method of thereof - Google Patents

Abstract

PURPOSE: A latex modified concrete composition including by-product from steel making process and a manufacturing method thereof are provided to remarkably reduce amount of cement and latex and enhance workability and intensity of concrete. CONSTITUTION: A latex modified concrete composition including by-product from steel making process comprises 10-15 weight% of cement, 2-5 weight% of high mass activity blast furnace slag powder, 1-3 weight% of latex, 2-5 weight% of water, 43-47 weight% of quenching agent steel slag, and 33-37 weight% of coarse aggregate. The high mass activity blast furnace slag powder has fineness of 5,000-5,400 cm^2/g and includes blast furnace slag, calcium hydroxide, and anhydrous gypsum in weight ratio of 87:7:6.

Description

Latex modified concrete composition containing steel by-products and a method for manufacturing the same

The present invention relates to a latex-modified concrete composition comprising a steel by-product and a method for manufacturing the same, and more particularly, a high activity of pre-mixing calcium hydroxide as an active agent and anhydrous gypsum into a blast furnace slag having a powder degree of 5,000 to 5,400 cm ² / g. Using blast furnace slag powder as binder and quenching steel slag as fine aggregate, workability and compression of concrete? The present invention relates to a latex modified concrete composition and a method for manufacturing the same, which include steel by-products which are economical and environmentally friendly by improving bending strength and durability, and significantly reducing the content of cement and latex in concrete.

In general, latex modified concrete (LMC) is a bridge pavement concrete introduced in Korea in the 1990s, and has been widely used for paving highways and national roads due to its excellent adhesive strength, flexural strength, and waterproof performance. However, the conventional LMC concrete composition has a high cement content and a large amount of dry shrinkage tends to cause cracking, and it has a disadvantage in that it is economical by using a large amount of latex, which is an expensive admixture.

On the other hand, blast furnace slag and steel slag produced by Korea's steel industry are 9.5 million tons and 7.5 million tons respectively, totaling 17 million tons, and these slag are industrial by-products generated from blast furnace or electric furnace or converter in refining steel raw materials. In the case of disposal as it is without using it, there have been various studies to utilize it due to environmental problems such as scattering dust and leachate.

However, when ground granulated blast-furnace slag is used as concrete admixture, it has been proved to be effective in improving long-term strength and durability. Steelmaking slag contains free calcium oxide (CaO) inside, which can not be used as concrete aggregate because it can expand the volume when it comes in contact with water, causing the concrete to crack. It has been.

Recently, researches on active agents to increase the initial reactivity of blast furnace slag have been actively conducted, and as a way to increase the stability of steel slag, the steel slag is quenched using high-speed air to produce free calcium oxide (CaO). In order to control and control the shape of spherical fine aggregates, a research is being actively conducted to recycle them into concrete aggregates.

Therefore, the present inventors prepared a highly active blast furnace slag powder in which the calcination blast furnace slag having a powder degree of 5,000-5,400 cm ² / g was previously mixed with calcium hydroxide [Ca (OH) ₂ ] and anhydrous gypsum (CaSO ₄ ). By using binders and replacing most of the natural aggregates with spherical quenching steel slag, not only can it prevent concrete deterioration due to depletion of natural aggregates, but it can also increase the recycling of industrial by-products and achieve economic cost savings. The high performance concrete composition has been developed to complete the present invention.

[Document 1] Republic of Korea Patent No. 1010597 (name of the invention: high-performance concrete composition using slag, July 21, 2011 announcement) Republic of Korea Patent No. 696314 (Invention name: crude steel synthetic latex modified concrete composition, 2007.03.20. Notification)

The present invention has been made in order to solve the above problems, to prevent the degradation of concrete due to environmental protection and natural aggregate depletion, as well as to expand the recycling of industrial by-products, the content of the most expensive cement and latex in the concrete composition It is an object of the present invention to provide a high-performance latex modified concrete composition and a method for manufacturing the same, which can significantly reduce the economic effect of cost reduction.

In addition, an object of the present invention is to provide a high-performance latex modified concrete composition and a method for producing the same, which can drastically reduce the amount of dry shrinkage acting as a major cause of cracking of concrete by reducing cement content.

In addition, the present invention is a high-performance latex with a high powder high activity blast furnace slag powder and spherical quenching steel slag particles, the fluidity in the solid state is greatly increased, the water tightness of the concrete can be maximized, the water resistance is dramatically increased It is an object of the present invention to provide a modified concrete composition and a method of manufacturing the same.

In order to achieve the above object, the latex modified concrete composition and a manufacturing method comprising the steel by-product of the present invention in the latex modified concrete composition comprising cement, latex, water, natural fine aggregate and coarse aggregate, the cement It is characterized by using a part of the highly active blast furnace slag (water 滓) slag powder as a binder, and replacing all of the natural residue aggregates with quenching steel slag.

In addition, the latex modified concrete composition comprising a steel by-product of the present invention 10 to 15% by weight cement, 2 to 5% by weight of highly active blast furnace slag powder, 1 to 3% by weight latex, 2 to 5% by weight of water %, Rapidly Cooled Steel Slag (Rapidly Cooled Steel Slag) is characterized in that it comprises 43 to 47% by weight and coarse aggregate 33 to 37% by weight.

In addition, the method for producing a latex-modified concrete composition comprising the steel by-product of the present invention is a) 10 to 15% by weight of cement, 2 to 5% by weight of highly active blast furnace slag powder and rapidly cooled steel slag (Rapidly Cooled Steel) Slag) mixing 43 ~ 47% by weight, b) mixing 33 ~ 37% by weight coarse aggregate in the mixture of step a), c) mixing 1-3% by weight of the latex to the mixture of step b) And d) mixing 2 to 5% by weight of water to the mixture of step c).

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Highly active blast furnace slag powder according to the present invention is used to improve the weight loss, strength and durability of the cement, blast furnace slag: calcium hydroxide: anhydrous gypsum in a ratio of 87: 7: 6 by weight After mixing, the powder is preferably prepared by grinding the powder to 5,000 to 5,400 cm ² / g.

When the blast furnace slag is less than 85% of the total composition of the highly active blast furnace slag powder, the initial strength is excellent, but the long-term strength improvement rate and long-term durability tend to be lowered. Initial strength drops.

Calcium hydroxide [Ca (OH) ₂ ] is a material for improving the activity of blast furnace slag. When the activity is less than 5% with respect to the total composition of the highly active blast furnace slag powder, the initial strength increase rate is lowered, and is greater than 10%. In this case, an alkali dissolution phenomenon occurs, whitening appears on the concrete surface, and the surface is broken.

Anhydrous gypsum (CaSO ₄ ) is a swelling agent for improving the activity of blast furnace slag and drying shrinkage compensation. When it is less than 5% of the total composition of highly active blast furnace slag powder, the initial strength increase rate decreases and dry shrinkage reduction effect is reduced. Small and above 10% lowers the long-term strength of the concrete and causes the volume expansion crack of the concrete.

If the powder of the highly active blast furnace slag powder is less than 5,000, the specific surface area of the powder is small and the activity is lowered. If it is more than 5,400, the viscosity of the concrete increases, the workability is decreased, and the activity improving effect is produced. It is preferable that the high activity blast furnace slag powder is pulverized so as to have a powder degree of 5,000 to 5,400 cm ² / g since the cost is not economically low.

The highly active blast furnace slag powder is preferably used in the range of 2 to 5% by weight based on the total concrete composition of the present invention. In the case of less than 2% by weight, the effect of reducing cement is small, in the case of more than 5% by weight, the initial strength is lowered and the unit quantity is increased.

The latex according to the present invention may be SB (60 to 70% by weight of styrene, 30 to 40% by weight of butadiene) latex, acrylic latex and the like, but it is preferable to use SB latex.

This is because SB latex is more viscous than acrylic latex, which reduces the risk of material separation when mixing various materials with different specific gravity and manufacturing high flow concrete.

The latex is preferably used in the range of 1 to 3% by weight based on the total composition of the concrete of the present invention. If it is less than 1% by weight, the waterproof performance and viscosity are reduced, and if it is more than 3% by weight, there is a risk of material separation.

Rapidly Cooled Steel Slag according to the present invention includes a liquid steel slag generated in a steelmaking process of a steel mill in a pot, and then the liquid steel slag is sprayed in an area where water is mixed with a high-pressure gas. The liquid steelmaking slag is supplied with the kinetic energy of the mixed gas mixed with the water to be divided into numerous fine droplets, and the divided fine droplets are spherical due to the surface tension. It is preferable that the particle size distribution is 0.15 to 2.5 mm. Since the quenched steel slag with the particle size of 0.15 ~ 2.5mm has the highest spherical ratio, the highest performance rate, the higher the performance rate, the more water-tight concrete can be produced, and the amount of unit cement and quantity can be reduced.

Rapidly Cooled Steel Slag (Rapidly Cooled Steel Slag) is preferably used in the range of 43 to 47% by weight relative to the total composition of the present invention. If it is less than 43% by weight, the strength performance and surface finish of the concrete is lowered, in the case of more than 47% by weight there is a disadvantage that the material separation and unit weight is increased.

As the cement according to the present invention, it is preferable to use one kind of Portland cement. As the highly active blast furnace slag powder is used as a binder to replace a part of the cement, the concrete composition of the present invention is 10 to 15. Preference is given to using in the weight% range.

Water according to the present invention is preferably used in the range of 2 to 5% by weight based on the total concrete composition of the present invention. If less than 2% by weight, workability and surface finish performance is inferior, in the case of more than 5% by weight there is a risk of material separation and bleeding, there is a problem of low strength expression performance.

Coarse aggregate according to the present invention is preferably used in the range of 33 to 37% by weight relative to the total concrete composition of the present invention. If the coarse aggregate is used less than 33% by weight, the unit capacity is increased to decrease the strength performance, the viscosity is increased, the workability is reduced, when used in excess of 37% by weight coarse concrete is produced to reduce the surface plastering performance do.

As described above, the present invention recycles blast furnace slag and steelmaking slag, which are industrial by-products, by using high activity blast furnace slag powder as a binder and quenching steel slag as fine aggregate, which is environmentally friendly, and has improved performance and strength performance. Concrete can be manufactured, and the economic effect of cost reduction can be obtained by drastically reducing the amount of expensive cement and latex.

In addition, it is possible to drastically reduce the amount of dry shrinkage by reducing the cement content as well as preventing concrete quality deterioration due to depletion of natural aggregates, thereby improving cracking and waterproofing performance.

Figure 1 is a photograph showing the shape of the quenching steel slag.
2 is a graph showing the characteristics of the rate of change in length by mixing case.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are not intended to limit the scope of the present invention, and ordinary changes by those skilled in the art are possible within the scope of the technical idea of the present invention.

≪ Example 1 >

Preparation of Highly Active Blast Furnace Slag

Highly active blast furnace slag of the present invention was prepared by pulverizing the powder to 5,200 cm ² / g after mixing the existing blast furnace slag fine powder: calcium hydroxide: anhydrous gypsum in a 87: 7: 6 weight ratio.

The existing blast furnace slag slabs are made of three types of blast furnace slag (manufacturer: Korea Basic Materials), which are widely used in Korea. It was purchased and used.

Physical properties of the existing blast furnace slag slag and the highly active blast furnace slag according to the present invention prepared as described above are shown in Table 1 below.

As can be seen in Table 1, when the activity of the highly active blast furnace slag powder is higher than the existing blast furnace slag powder, when the high activity blast furnace slag powder is used in concrete, the amount of unit cement is reduced and strength is enhanced. In addition, it can be seen that the high degree of powder enables the manufacture of watertight concrete, thereby improving the waterproofing performance and reducing the amount of latex.

<Example 2>

Manufacturing of Rapidly Cooled Steel Slag

In the quenching steel slag of the present invention, a liquid steelmaking slag generated in a steelmaking process of a steel mill is placed in a pot, and then a liquid steelmaking slag is flowed into an area where a high-pressure gas mixed with water is sprayed, thereby forming a liquid steelmaking slag. It was prepared by receiving the kinetic energy of the mixed gas mixed with water to be divided into a number of fine droplets, and the divided fine droplets were spherical due to the surface tension was cooled by water or air.

The granulation of the quenched steel slag thus prepared is as shown in Figure 1, the physical properties are shown in Table 2 below.

type Density (g / cm 3) % Of performance Absorption rate (%) sand 2.62 59.4 1.5 Quenching steel slag 3.54 70.5 0.02

As can be seen in Table 2 and Figure 1, the density of the quenching steel slag is 3.54 higher than the density of the sand, since the granulation of the quenching steel slag is close to the spherical shape, the performance rate is also 70.5%, about 10% higher than the sand Since it is close to the sphere, when used as fine aggregate for concrete composition, it has the effect of improving the flowability and strength of concrete, and it is possible to produce economical concrete by reducing the amount of cement and latex due to the high performance rate. Will be.

<Example 3>

To prepare a latex modified concrete composition (example) comprising a conventional latex modified concrete (comparative example) and the high-performance steel by-product of the present invention in the mixing ratio as shown in Table 3.

&Lt; Test Example 1 >

Slump measurement

According to KS F 2402 "Test method for concrete slump", the concrete composition of Example and Comparative Example was compacted 25 times in a slump cone having a bottom diameter of 20 cm, a top diameter of 10 cm, a height of 30 cm and a thickness of 1.5 mm or more. After filling up and lifting the slump cone vertically, the difference from the specimen height in the center of the concrete was measured in 5mm units.

Air volume measurement

According to SF 2421 `` Testing method of air volume of concrete not hardened by pressure method '', the concrete composition of Example and Comparative Example was tipped 25 times each 1/3 times and the sides of the container were filled with wood hammer 10 times, and the surface was smoothed. After attaching the cover and tightening to prevent air leakage, close all the valves, make the air chamber pressure higher than the initial pressure with the air hand pump, open the control valve, match the needle of the pressure gauge to the scale of the initial pressure, and then operate the operation valve. Open air was measured.

Compressive strength measurement

According to KS F 2405 `` Test Method for Concrete's Compressive Strength '', the specimens of the concrete compositions of Examples and Comparative Examples were placed so that their central axes coincide with the centers of the pressure plates. The compressive strength was measured by applying a load at a constant speed so as not to give an impact.

Flexural strength measurement

In accordance with KS F 2408, `` Testing Method of Flexural Strength of Concrete '', when the specimens of the concrete compositions of Examples and Comparative Examples were filled with concrete in the mold, the upper and lower sides of the specimens were placed in the center of the bearing butterfly, and the upper pressurizing device was contacted to the third point of the ground. After the test specimens were fractured between the three points of the centerline of the tension-side surface-interface direction, the flexural strength was measured.

The test results are shown in Table 4 below.

As can be seen in Table 4, the concrete using the latex modified concrete composition comprising the high-performance steel by-product of the present invention is much higher compressive strength and flexural strength even using less cement and latex than conventional latex modified concrete Could see.

&Lt; Test Example 2 &

Dry Strain Strain Measurement

The concrete dry shrinkage strain over time of the concrete composition of the Examples and Comparative Examples was measured.

According to KS F 2424 Test Method for the Change of Length of Mortar and Concrete, the specimens were prepared by using LVDT with a sensitivity of 0.001mm while maintaining the ambient temperature at 20 ℃ and 60% humidity and maintaining the temperature and humidity. After measuring the change in length of the length change rate was calculated by the following formula.

L ₀ : reference length

X ₀₁ , X ₀₂ : Measured value at each reference point

X _i1 , X _i2 : Measured value at time point i respectively

The results are shown in Table 5 and FIG. 2.

As can be seen in Table 5 and Figure 2, when looking at the concrete dry shrinkage strain (length change rate) according to the time of the concrete composition of the comparative example and the embodiment, the embodiment of the present invention is dry shrinkage strain (length change rate) than the comparative example Could see a lot smaller). The reduction of the dry shrinkage will be a major factor to suppress the occurrence of concrete cracks.

<Test Example 3>

Chlorine Ion Penetration Characteristics

In general, the waterproofness of concrete is evaluated by the chlorine ion penetration test. In the test, the electrode containers are fixed on both sides of the concrete, and the circuits are constructed by using the electrodes from these containers as terminals. As a method of evaluating the degree of permeability, the measured voltage is converted into a current value, and the total amount of electric charge passed is expressed as Coulomb.

Table 6 below is a permeation characteristic evaluation table through the chlorine ion penetration test specified in KS F2711.

coulomb Permeability Rating More than 4000 High permeability 2000 ~ 4000 usually 1000-2000 lowness 100-1000 Very low 100 or less Impervious

Concrete waterproof performance (chlorine ion permeation performance) with time of the concrete composition of the Example and Comparative Example was measured by the same method as described above.

The results are shown in Table 7 below.

As can be seen in Table 7, when looking at the concrete chlorine ion permeation performance (waterproof performance) of the concrete composition of the Comparative Example and Example according to the time, it can be seen that the embodiment of the present invention is much less chlorine ion permeability than the comparative example Could. This means that the latex modified concrete composition including the high performance steel by-product of the present invention has increased waterproof performance than conventional latex-modified concrete due to the use of steel by-products despite the low content of cement and latex.

Claims (10)

In the latex modified concrete composition comprising cement, latex, water, natural fine aggregate and coarse aggregate,
A part of the cement is replaced with a highly active blast furnace slag powder and used as a binder,
Latex-modified concrete composition comprising a steel by-product, characterized in that to replace all of the natural residue aggregates with Rapidly Cooled Steel Slag (Rapidly Cooled Steel Slag).
10-15 wt% of cement, 2-5 wt% of highly active blast furnace slag powder, 1-3 wt% of latex, 2-5 wt% of water, 43-47 wt% Rapidly Cooled Steel Slag Latex modified concrete composition comprising a steel by-product, characterized in that it comprises a% and coarse aggregate 33 to 37% by weight.
The method according to claim 1 or 2,
The high activity blast furnace slag powder is a powder of 5,000 ~ 5,400cm ² / g, blast furnace slag (calcium hydroxide): anhydrous gypsum is characterized in that it is prepared by mixing in a weight ratio of 87: 7: 6. Latex modified concrete composition comprising a steel by-product.
The method of claim 2,
The latex is a latex modified concrete composition comprising a steel by-product, characterized in that SB (Styrene Butadiene) latex.
The method of claim 2,
Rapidly cooled steel slag (Rapidly Cooled Steel Slag) is a latex modified concrete composition comprising a steel by-product, characterized in that the particle size distribution is 0.15 ~ 2.5mm.
In the method for producing a latex modified concrete composition comprising cement, latex, water, natural fine aggregate and coarse aggregate,
A part of the cement is replaced with a highly active blast furnace slag powder and used as a binder,
Method for producing a latex modified concrete composition comprising a steel by-product, characterized in that to replace all of the natural residue aggregate with a quenching steel slag.
a) mixing 10 to 15% by weight of cement, 2 to 5% by weight of highly active blast furnace slag powder, and 43 to 47% by weight of Rapidly Cooled Steel Slag;
b) mixing 33 to 37% by weight coarse aggregate in the mixture of step a);
c) mixing 1 to 3% by weight of the latex to the mixture of step b); And
d) a method for producing a latex modified concrete composition comprising a steel by-product, characterized in that it comprises the step of mixing 2 to 5% by weight of water in the mixture of step c).
The method according to claim 6 or 7,
The high activity blast furnace slag powder is a powder of 5,000 ~ 5,400cm ² / g, blast furnace slag (calcium hydroxide): anhydrous gypsum is characterized in that it is prepared by mixing in a weight ratio of 87: 7: 6. Method for producing a latex modified concrete composition comprising a steel by-product.
The method of claim 7, wherein
The latex is a method for producing a latex modified concrete composition comprising a steel by-product, characterized in that SB (Styrene Butadiene) latex.
The method of claim 7, wherein
The rapid cooling steel slag (Rapidly Cooled Steel Slag) is a method for producing a latex modified concrete composition comprising a steel by-product, characterized in that the particle size distribution is 0.15 ~ 2.5mm.

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