KR102014870B1 - Super low heat cementless binder for mass concrete - Google Patents

Abstract

The present invention relates to cementless binder, and more specifically, to suppress the initial hydration reaction, the concrete concrete that solves the performance degradation due to the heat of hydration, that is, the temperature cracking due to the internal and external temperature difference and the durability problem of the connecting portion due to the connection. An ultra low heat cementless binder for use.

Description

Super low heat cementless binder for mass concrete

The present invention relates to cementless binder, and more specifically, to suppress the initial hydration reaction, the concrete concrete that solves the performance degradation due to the heat of hydration, that is, the temperature cracking due to the internal and external temperature difference and the durability problem of the connecting portion due to the connection. An ultra low heat cementless binder for use.

Cement and cements (alkaline activated slag binders) generate a relatively large amount of heat of hydration at the beginning of the hydration reaction at which curing begins. General structures with large surface area to volume ratios can naturally cool down to atmospheric exposure, taking into account thermal conductivity. However, bulk mass concrete has a small surface area to volume, which makes natural cooling impossible. In addition, internal and external temperature difference occurs, and defects such as temperature cracking occur due to internal restraint stress resulting from thermal deformation difference. Therefore, in order to reduce the heat of hydration due to the problem of heat of hydration during mass concrete casting, the method of lowering the internal temperature by using pipe cooling and the method of lowering the calorific value due to the hydration reaction by using low heat concrete, concrete The method of dividing the cross section of a member by dividing is used.

However, the low exothermic cement lowers the content of C3S or C3A and uses a large amount of C2S, which is less reactive. The reduction effect is not so great.

Cement Type Mineral composition (%) Compressive strength (MPa) Hydration Heat (J / g) C3S C2S C3A C4AF 3 days 7 days 28 days 7 days 28 days Type 1 usually 49 23 10 9 20 29 38 339 385 2 types Middle heat 42 35 5 12 16 23 37 285 330 3 types Crude steel 59 16 12 8 30 37 47 356 419 4 types Low heat 31 48 3 11 13 18 34 246 286 5 types Sulfate 46 32 4 13 19 27 39 272 335

In addition, the introduction of cooling pipes increases the cost of construction due to additional equipment and equipment.

In order to solve this problem, a number of techniques using a binder (fly ash, blast furnace slag fine powder, etc.) that express low heat of hydration as a binder have been disclosed as follows.

Korean Patent No. 1997-0042387 (Low Heat Generation Low Shrinkage Concrete Composition Containing Fly Ash) replaces a portion (15-40 wt%) of cement constituting concrete with fly ash and adds a large amount of admixture. By greatly reducing the amount of unit cement and the amount of unit by reducing the amount of hydration calorific value and drying shrinkage. Korean Patent No. 1997-0042391 (Low Heat Generation Low Shrinkage Concrete Composition Containing Slag Fine Powder) is used to replace a part of cement (20-50 wt%) of the cement constituting concrete with fine slag powder or use slag cement and admixture. By adding a large amount, the amount of unit cement and unit water are greatly reduced to reduce the amount of heat of hydration and drying shrinkage. Patent No. 1997-0042388 (Low heat generation low shrinkage concrete composition containing three-component cement) is a unit cement amount by replacing a portion of the cement with fly-ash and slag fine powder and adding a large amount of admixture And it is intended to reduce the amount of hydration calorific value and drying shrinkage by greatly reducing the unit quantity. This is to use fly ash and fine slag powder together with cement. When excessive use of fly ash or fine slag powder has the above-mentioned problems, it is composed of three components, but the problem of delayed setting time and bleeding is not overcome. Does not seem to be. Korean Patent No. 2001-0037292 (Method for producing low-heat concrete using fly ash and organic admixture) replaces a part of cement with fly ash and forms various types of organic admixtures, thereby providing high fluidity to concrete. In addition to reducing slump loss and heat of hydration, to suppress drying shrinkage, and to enhance the long-term strength, the organic admixture is 60 to 80% by weight of the naphthalene-based high fluidizing agent, 10 to 10 g of sodium gluconate It is shown that it is 30 weight%, 5 to 10 weight% of polyacrylamide, and 5 weight% or less of AE (Air entraining agent) agent is shown. Patent No. 0874584 (Low Heat Ultra High Strength Concrete Composition) uses a binder in which blast furnace slag fine powder, silica fume and anhydrous gypsum are mixed in an appropriate ratio as a binder and blended at a low water-binder ratio of 10 to 17% by weight. It relates to a low heat generation ultra-high strength concrete composition expressing strength over 120 MPa while securing a constant workability.

However, the low heat concrete composition known so far contains cement, so it was necessary to develop a low heat concrete composition using cement that did not use cement at all, but using cement cement (alkali activated slag binder) instead of cement When the concrete is poured, high heat of hydration is generated by ionization of the initial alkali activator and recombination of slag, and when the activator with low reactivity (pH) is used to suppress it, the strength expression is lowered. Existed.

The present inventors completed the present invention by developing an ultra-low heat generating cement binder which can significantly reduce the heat of hydration as a result of research efforts to develop the cement cement binder which can solve the above-mentioned problems.

Therefore, an object of the present invention is to control the ionization rate, ionization rate, etc. of the stimulant that affects the reaction rate to suppress the initial reaction rate and increase the reaction holding time in the long term to reduce the heat of hydration and to improve the final strength It is to provide a four-component alkali activator for exothermic cement binder.

Another object of the present invention is to significantly reduce the heat of hydration by greatly inhibiting the initial hydration reaction by using a four-component alkali activator to significantly reduce the heat of hydration, i.e. durability of the connection part by connecting with temperature cracking due to internal and external temperature differences. It is to provide an ultra-low heat generation cement binder with a new composition that can secure a final strength of 30-55 MPa without problems.

Yet another object of the present invention is that the initial heat of hydration is very low when forming a mass concrete structure as an ultra low heat cement cement binder, so that it can be poured without the installation of a cooling device or a one-time casting amount limit (resulting), thereby reducing the construction cost and reducing the air. In addition, since there is no internal defect and can express high strength, it is to provide a mass concrete structure that is advantageous for securing the strength and durability of the structure.

The object of the present invention is not limited to the above-mentioned object, and even if not explicitly stated, the object of the invention that can be recognized by those skilled in the art can be naturally included from the description of the detailed description below. .

In order to achieve the above object of the present invention, the present invention provides a four-component alkali activator for ultra-low heat cementedum binder comprising calcium hydroxide, sodium sulfate, sodium fluoride and potassium carbonate.

In a preferred embodiment, the calcium hydroxide, sodium sulfate, sodium silicon fluoride and potassium carbonate are each blended in a weight ratio of 7 to 10: 1 to 3: 1 to 3: 0.5 to 2.

In a preferred embodiment, the calcium hydroxide acts as a main activator, sodium sulfate acts as an auxiliary activator for strength enhancement, the sodium fluoride acts as an activator for adjusting the hydration reaction rate and reaction holding time, the potassium carbonate It acts as an activator for reaction rate control and final strength increase.

In a preferred embodiment, the calcium hydroxide, sodium sulfate, sodium silicon fluoride and potassium carbonate are powders.

In addition, the present invention is a blast furnace slag; And a four-component alkali activator comprising calcium hydroxide, sodium sulfate, sodium fluoride, and potassium carbonate.

In a preferred embodiment, the blast furnace slag is contained 82% to 90.5% by weight relative to the total binder, the four-component alkali activator is included from 9.5% to 18% by weight relative to the total binder.

In a preferred embodiment, the calcium hydroxide, sodium sulfate, sodium fluoride and potassium carbonate contained in the four-component alkali activator are each blended in a weight ratio of 7 to 10: 1 to 3: 1 to 3: 0.5 to 2.

In a preferred embodiment, the four-component alkali activator is in powder form.

In a preferred embodiment, the age 70-hour cumulative heat of hydration is 70 J / g or less and age 28 days compressive strength is 30 ~ 55 MPa.

In addition, the present invention provides a mass concrete structure comprising any one of the ultra-low heat cementing material binder described above.

According to the four-component alkali activator of the present invention described above, by controlling the ionization degree, ionization rate, etc. of the stimulant that affects the reaction rate of the blast furnace slag to suppress the initial reaction rate and increase the reaction holding time in the long term to reduce the heat of hydration and ultimate strength Can improve.

In addition, according to the ultra-low calorific cement binder of the present invention, by significantly suppressing the initial hydration reaction by using a four-component alkali activator, the heat of hydration is remarkably reduced, thereby degrading performance due to hydration heat, that is, temperature cracking due to internal and external temperature differences. The final strength can be secured at 30 ~ 55 MPa without any problems with the durability of the connection part due to the stroke.

In addition, since the initial heat of hydration is very low when forming the mass concrete structure with the binder of the present invention, it can be poured without the installation of the cooling device or the one-time pouring amount limit (breaking), thereby reducing the construction cost and reducing the air, and there is no internal defect. Since it can express high strength, it is advantageous to secure the strength and durability of the structure.

These technical effects of the present invention are not limited to the above-mentioned range, and even if not explicitly stated, the effects of the invention that can be recognized by those skilled in the art from the description of the specific contents for the implementation of the following invention are also mentioned. Of course included.

1 is a graph showing the heat transfer rate of hydration heat insulation by binder.
Figure 2 is a graph showing the heat of hydration (accumulated calorific value) thermal insulation temperature increase by binder.

The terms used in the present invention have been selected as widely used general terms as possible in consideration of the functions in the present invention, but this may vary according to the intention or precedent of the person skilled in the art, the emergence of new technologies and the like. In addition, in certain cases, there is also a term arbitrarily selected by the applicant, in which case the meaning will be described in detail in the description of the invention. Therefore, the terms used in the present invention should not be interpreted based on the general meaning of the term but the contents described throughout the specification of the present invention, rather than simply the name of the term. In particular, when the terms "about", "substantially" and the like are used, they may be interpreted as being used at or near that numerical value when a manufacturing and material tolerance unique to the stated meaning is given. .

Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and that one or more other features It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, actions, components, parts or combinations thereof.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

Hereinafter, with reference to the accompanying drawings and preferred embodiments will be described in detail the technical configuration of the present invention.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Like reference numerals used to describe the present invention throughout the specification denote like elements.

The technical feature of the present invention is to control the ionization rate, ionization rate, etc. of the alkali activator that affects the reaction rate during the hydration reaction of the blast furnace slag to suppress the initial reaction rate and increase the reaction holding time in the long term, while reducing the final heat of hydration and ultimate strength. The four-component alkali activator of the new composition that can be improved and the cement binder comprising the same.

Accordingly, the four-component alkali activator of the present invention includes calcium hydroxide, sodium sulfate, sodium silicon fluoride and potassium carbonate.

That is, when potassium carbonate, calcium hydroxide, sodium sulfate, and sodium fluoride, which are not normally used as alkali activators, are mixed in a certain amount and used as a stimulant to make the blast furnace slag hydraulic, the initial hydration reaction rate can be suppressed to suppress the heat of hydration. Not only that, but after 28 days of age, sufficient intensity was possible.

As such, the four-component alkali activator of the present invention suppresses the initial reaction rate by controlling the ionization degree, ionization rate, etc. of the alkali activator that affects the reaction rate by including the components selected in consideration of the series and the anion of the activator. In the long run, the reaction holding time can be extended to reduce the heat of hydration and ultimately to improve the strength. In particular, calcium hydroxide and sodium sulfate were selected as the main stimulants for strength expression, sodium fluoride was selected to adjust the hydration reaction rate and reaction holding time, and potassium carbonate was selected for the control of hydration reaction rate and ultimate strength.

In addition, the four-component alkali activator of the present invention is calcium hydroxide (Ca (OH) ₂ ), sodium sulfate (Na ₂ SO ₄ ), sodium fluoride (Na ₂ SiF ₆ ) and potassium carbonate (KCO ₃ ) 7-10: It can be completed by blending in a weight ratio of 1 to 3: 1 to 3: 0.5 to 2. The type and content ratio of each component were determined experimentally, and beyond the defined range, the intended effects of suppressing the generation of hydration heat and enhancing final strength were reduced.

In addition, the quaternary alkali activator of the present invention can suppress the initial rapid reaction by using the powder phase, unlike the alkaline activator used as a stimulant for decomposing the glass of the blast furnace slag powder, which is the main material of the cementless binder in the prior art .

Next, the ultra low heat cementing material of the present invention is blast furnace slag; And a four-component alkali activator composed of calcium hydroxide, sodium sulfate, sodium fluoride, and potassium carbonate.

Here, the blast furnace slag is contained 82% to 90.5% by weight relative to the total binder, the four-component alkali activator may be included in the 9.5% to 18% by weight relative to the total binder, the mixing ratio of the blast furnace slag and four-component alkali activator is also experimental Outside the defined range, the intended effects of suppressing the heat of hydration and ultimately increasing the intensity were reduced.

As described above, the ultra-low calorific cement binder of the present invention containing a four-component alkali activator has a cumulative heat of hydration of 70 J / g or less for 70 hours and shows a compressive strength of 30 to 55 MPa for 28 days. Therefore, the heat of hydration was remarkably low, but the strength expression was equal or more, and the ultimate strength was rather excellent as described later.

As a result, the mass concrete structure formed of the ultra-low heat cementing cement binder of the present invention can be poured without the installation of a cooling device or the limit of one-time pouring amount because the initial heat of hydration is very low at the time of forming the structure, thereby reducing the construction cost and air shortening effect. There is no internal defect and can express up to high strength, which is advantageous for securing the strength and durability of the structure.

Examples 1-14

The four-component alkali activators 1 to 7 were prepared by the formulation as shown in Table 2 below, and ultra low heat cementing material binders 1 to 7 were prepared by the formulation as shown in Table 3 below.

division Ca (OH) ₂
(Unit: weight%) Na ₂ SO ₄
(Unit: weight%) Na ₂ SiF ₆
(Unit: weight%) KCO ₃
(Unit: weight%) Example 1 7.0 1.0 3.0 0.5 Example 2 7.0 1.0 3.0 1.0 Example 3 7.0 1.0 3.0 1.5 Example 4 7.0 1.0 3.0 2.0 Example 5 7.0 3.0 3.0 2.0 Example 6 7.0 3.0 3.0 0.5 Example 7 7.0 3.0 3.0 1.0

division Blast furnace slag
(Unit: weight%) 4-component alkali activator
(Unit: weight%) Example 8 88.5 11.5 Example 9 88 12 Example 10 87.5 12.5 Example 11 87 13 Example 12 85 15 Example 13 86.5 13.5 Example 14 86 14

Comparative Examples 1 to 14

Comparative Examples Alkali Activators 1 to 7 were prepared in the formulation as shown in Table 4, and Comparative Example Cement Binders 1 to 7 were prepared in the formulation as in Table 5 below.

division Ca (OH) ₂
(Unit: weight%) Na ₂ SO ₄
(Unit: weight%) Na ₂ SiF ₆
(Unit: weight%) Comparative Example 1 3 4 Comparative Example 2 10 Comparative Example 3 7.0 Comparative Example 4 7.0 3.0 Comparative Example 5 7.0 1.0 Comparative Example 6 7.0 2.0 Comparative Example 7 7.0 3.0

division Blast furnace slag
(Unit: weight%) Comparative Example Alkali Activator
(Unit: weight%) Comparative Example 8 93 7 Comparative Example 9 90 10 Comparative Example 10 93 7 Comparative Example 11 90 10 Comparative Example 12 92 8 Comparative Example 13 91 9 Comparative Example 14 90 10

Experimental Example 1

Compressive strength (MPa) and heat of hydration (J / g) for each of the following types of materials: Portland Cement (OPC), Comparative Cement Binder 1, Comparative Cement Binder 2 and Ultra Low Heat Cement Binder 6 Was measured and the results are shown in Table 6, FIG. 1 and FIG.

Mortar test specimens were prepared according to KS L 5105 (cement mortar compressive strength test method), and the specimens were sealed and cured so that they did not come into contact with the outside air until the compressive strength test date after curing. In addition, the compressive strength test was carried out in accordance with KS L 5105 on the 3rd, 7th and 28th day of reinforcement using a universal testing machine (UTM) with a maximum load of 300kN (resolution 10N).

The heat of hydration is measured by the cement hydration calorimeter (CHC-OM6), which measures 10 g of each sample and plots the adiabatic temperature rise curve of Tokyo Rico's microhydration heat. It was measured for 3 days, which is almost the end point. 1 is a graph showing the heat of hydration heat rise rate for each binder, and FIG. 2 is a graph showing the heat of hydration rate data shown in FIG. 1 as a cumulative calorific value with time.

Binder type Compressive strength (MPa) Hydration Heat (J / g) 3 days 7 days 28 days 3 days Class 1 Ordinary Portland Cement (OPC) 20 29 38 232 Comparative Cement Binder 1
(NaOH-based cement binder)
21.62
24.84
30.15
174 Comparative Cement Binder 2
(Na ₂ SiO ₃ based cementless binder)
16.48
26.11
32.18
143 Ultra Low Heat Cement Binder 6 5.45 26.87 41.55 60

From Table 6, Figures 1 and 2 it can be seen that the ultra-low calorific cement used with the four-component alkali activator of the present invention has the highest initial heat of hydration, while the initial heat of hydration is almost three times lower.

Experimental Example 2

According to the method of Experimental Example 1 to prepare a concrete test specimen for measuring the compressive strength of the ultra low heat cemented cement binders 1 to 7 obtained in Examples 7 to 14 and the comparative cement cement binders 1 to 7 obtained in Comparative Examples 7 to 14 Compressive strength was measured and the results are shown in Table 7.

division compressive strength 3 days 7 days 28 days Example 8 1.24 21.54 30.23 Example 9 0.84 18.85 32.96 Example 10 0.72 9.93 47.23 Example 11 0.68 8.80 52.62 Example 12 0.49 17.28 52.54 Example 13 5.45 26.87 41.55 Example 14 1.81 22.44 46.35 Comparative Example 8 21.62 24.84 30.15 Comparative Example 9 16.48 26.11 32.18 Comparative Example 10 7.43 8.51 12.42 Comparative Example 11 12.04 14.91 16.24 Comparative Example 12 7.43 8.51 11.41 Comparative Example 13 10.82 13.02 16.01 Comparative Example 14 13.05 16.42 18.14

Table 7 shows that the ultra-low heat cementing binder of the present invention has a lower initial expression strength than the comparative cementing binder, but the final strength measured at 28 days is very good.

Although the present invention has been shown and described with reference to preferred embodiments as described above, it is not limited to the above-described embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Claims (10)

Calcium hydroxide acts as a main activator, sodium sulfate acts as an auxiliary activator for strength enhancement, sodium fluoride acts as an activator for adjusting the hydration reaction rate and reaction holding time, and potassium carbonate acting as an activator for hydration reaction rate control and final strength enhancement Each is blended in a weight ratio of 7 to 10: 1 to 3: 1 to 3: 0.5 to 2,
By suppressing the initial reaction rate of the blast furnace slag by controlling the conditions affecting the hydration reaction rate of the blast furnace slag contained in the cement cement binder, including the degree of ionization and ionization rate through the type and the mixing ratio of the components to be blended A four-component alkali activator for ultra low heat cementless binder, characterized in that the heat of hydration of the binder is reduced and the ultimate strength is improved.
delete delete The method of claim 1,
The calcium hydroxide, sodium sulfate, sodium fluoride and potassium carbonate is a four-component alkali activator for ultra low heat cement cement binder, characterized in that the powder.
Blast furnace slag; And
Calcium hydroxide acts as a main activator, sodium sulfate acts as an auxiliary activator for strength enhancement, sodium fluoride acts as an activator for adjusting the hydration reaction rate and reaction holding time, and potassium carbonate acting as an activator for hydration reaction rate control and final strength enhancement 7 to 10: 1 to 3: 1 to 3: 0.5 to 2, respectively, in a weight ratio, which affects the hydration reaction rate of the blast furnace slag, including the degree of ionization and the rate of ionization, through the type and the mixing ratio of the components. It includes; four-component alkali activator for controlling the conditions;
The initial reaction rate of the blast furnace slag is suppressed, the heat of hydration is reduced, the ultimate strength is characterized in that the ultimate strength of cementless binder.
The method of claim 5,
The blast furnace slag is 82% by weight to 90.5% by weight relative to the total binder, the four-component alkali activator is characterized in that ultra-low heat fever cement binder is included in the 9.5% by weight to 18% by weight relative to the total binder.
delete The method of claim 5,
The four-component alkali activator is ultra-low heat fever cement binder, characterized in that the powder.
The method of claim 5,
70-hour cumulative heat of hydration is less than 70 J / g and age 28 days compressive strength is ultra-low heat cement cement binder, characterized in that 30 ~ 55 MPa.
10. A mass concrete structure comprising the ultra low heat cementing cement binder of any one of claims 5, 6, 8, and 9.

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