KR102111254B1 - Composition for shrinkage reduction cement, methods for manufacturing thesame and mortar composition - Google Patents

Abstract

The present invention is an alpha-type gypsum plaster; Anhydrite; lime; Auxinic expanders; And cement; The present invention includes a shrinkage control type cement composite composition for concrete. Through this, the present invention is applied to a concrete material, which has excellent crack control performance, realizes a volume reduction compensation property of concrete, improves the shrinkage control effect of reducing tensile stress, and has excellent flow, shrinkage reduction, and compressive strength. And, non-shrinkable, quick-hardness, roughness, high strength, initial strength enhancement effect, heat insulation, heat retention, antibacterial, humidity control and deodorization excellent cement control composite composition for concrete, its manufacturing method and the shrink control concrete It provides a mortar composition comprising a cement composite composition for.

Description

Shrinkage control type cement composite composition for concrete, its manufacturing method and mortar composition {COMPOSITION FOR SHRINKAGE REDUCTION CEMENT, METHODS FOR MANUFACTURING THESAME AND MORTAR COMPOSITION}

The present invention relates to a cement composite composition for shrink-controlled concrete, a method for manufacturing the same, and a mortar composition comprising the cement composite composition for shrink-controlled concrete.

Concrete is an artificial stone material that is hardened by mixing, kneading and mixing cement, aggregate, and water in an appropriate proportion. Concrete materials are one of the most widely used materials in the construction field, as they have superior performance in terms of workability, strength, durability, and maintenance as well as economical advantages.

Recently, in the construction field, the construction of large structures has increased, and the trend of high-rise buildings continues. Accordingly, the demand for high-strength and ultra-high-strength concrete is increasing. However, concrete materials may be cracked due to materials, construction conditions, variable environments, etc., and cracks may deteriorate performance, such as strength and durability of a construction structure. Therefore, solving such cracks has emerged as a priority when applying concrete materials.

Cracks occurring in concrete materials have various causes, but cracks due to dry shrinkage occurring before and after hardening of concrete act as a representative cause, which has hindered the development of related technologies.

Dry shrinkage refers to shrinkage that occurs as moisture inside the cured concrete evaporates to outside air under external environmental conditions where the concrete is dried. Specifically, the concrete always contains moisture therein, so that when placed in a dry environment or installed underground, such as an underground power tool, moisture evaporation may occur on the surface due to an increase in temperature. In this case, as the surface portion becomes dry, internal moisture moves to the surface portion by surface tension, and in this process, pressure is generated in the capillaries in the concrete pores, so that the movement of moisture can be accelerated. As a result, capillary tension and negative pressure in the pores are increased, and thus, shrinkage of the cured body may be caused in the concrete material. When the volume reduction occurs due to the shrinkage of the concrete material as described above, tensile stress occurs in the material, and when the tensile stress exceeds the allowable stress of the concrete, tensile cracks due to dry shrinkage occur.

In particular, it is very important for the concrete material to have its own shrinkage reduction characteristics because most of the external environmental conditions that cause dry shrinkage are difficult to control. For example, in urban power facilities that are buried underground, drying shrinkage is further accelerated by heat emitted from cables, and durability may be deteriorated due to accelerated deterioration, cracking, and the like. In addition, the concrete material used in the facility is very difficult to repair the crack due to the nature of construction in the ground, there is a problem that the maintenance cost is excessively high.

Therefore, in order to improve durability and long life of electric power tools such as urban electric power facilities buried underground, the need for research on concrete materials that can effectively control dry shrinkage and have excellent crack control characteristics is increasing.

One object of the present invention is excellent in economic efficiency, excellent crack control performance, realizing the volume reduction compensation properties of concrete, improved shrinkage control effect of reducing the tensile stress shrinkage control type cement composite composition for concrete and method of manufacturing the same Is to provide.

Another object of the present invention is to provide a cement composite composition for shrink-controlled concrete excellent in flowability, shrinkage reduction, and compressive strength, and a method for manufacturing the same.

Another object of the present invention is a shrinkage-control type concrete cement composite composition excellent in non-shrinkable, fast-hardening, high-strength, high-strength, initial strength-enhancing effect, heat insulation, warmth, antibacterial, humidity control and deodorization, and a method for manufacturing the same Is to provide

The above and other objects of the present invention can be achieved by the present invention described below.

One embodiment of the present invention is an alpha-type hemihydrate gypsum 3% to 16% by weight; 0.1% to 10% by weight of anhydrous gypsum; 0.1 to 1% by weight of lime; 0.1 to 3% by weight of the phosphorus-based expanding agent; And 70% to 96.7% by weight of cement; It relates to a cement composite composition for shrink-controlled concrete comprising a.

The alpha-type hemihydrate gypsum may be a wet phase transition material of flue gas desulfurization gypsum.

The alpha-type hemihydrate gypsum may have a powderiness of 1,300 cm ² / g to 1,500 cm ² / g.

The anhydrous gypsum may have a powderiness of 1,000 cm ² / g to 5,000 cm ² / g.

The anhydrous gypsum and the alpha-type hemihydrate gypsum may have a weight ratio of 1: 0.1 to 1: 6.

Another embodiment of the present invention is an alpha-type hemihydrate gypsum; Anhydrite; lime; Auxinic expanders; And cement; comprising the mixing, relates to a method for producing a cement composite composition for the above-described shrinkage control type concrete.

Another embodiment of the present invention, the above-mentioned shrinkage control type cement composite composition for concrete; And fine aggregate; relates to a mortar composition comprising a weight ratio of 1: 1 to 1: 3.

The additive may further include 1 to 10 parts by weight of the additive based on 100 parts by weight of the cement composite composition for shrink control.

The additive may be at least one of AE water reducing agent, fluidizing agent, high performance water reducing agent, accelerator, retarding agent, rapid setting agent, waterproofing agent, antirust agent, water-in-water separating agent, repair agent, anti-freezing agent and antifoaming agent.

The present invention is excellent in economic efficiency, has excellent crack control performance, realizes a volume reduction compensation property of concrete, improves the shrinkage control effect of reducing tensile stress, has excellent flow, shrinkage reduction and compressive strength, and has no Provided is a shrinkage-control type concrete cement composite composition having excellent shrinkability, fast stiffness, roughness, high strength, initial strength enhancement effect, heat insulation, heat retention, antibacterial, humidity control and deodorization, and a method for manufacturing the same.

1 is a graph showing the results of the shrinkage test for Examples 1 to 4 and Comparative Example 1 of the present invention.

Cement composite composition for shrink control type concrete

One embodiment of the present invention is an alpha-type hemihydrate gypsum 3% to 16% by weight; 0.1% to 10% by weight of anhydrous gypsum; 0.1 to 1% by weight of lime; 0.1 to 3% by weight of the phosphorus-based expanding agent; And 70% to 96.7% by weight of cement; It relates to a cement composite composition for shrink-controlled concrete comprising a.

Through this, the present invention is applied to a concrete material, has excellent crack control performance, realizes a volume reduction compensation property of concrete, improves the shrinkage control effect of reducing tensile stress, and has excellent flow, shrinkage reduction and compressive strength. And, non-shrinkable, quick-hardness, roughness, high strength, initial strength enhancement effect, heat insulation, heat retention, antibacterial, humidity control and deodorization excellent cement control composite composition for concrete, its manufacturing method and the shrink control concrete It provides a mortar composition comprising a cement composite composition for.

In particular, the cement composite composition for shrink-controlled concrete of the present invention includes alpha-type hemihydrate gypsum; Anhydrite; lime; And a phosphorus-based expander; by acting on the complex, it is possible to implement a volume reduction compensation property, flowability, shrinkage reduction and compressive strength of concrete more remarkably superior when only one of these components is added to cement.

The cement composite composition for shrinkage-controlled concrete of the present invention, for example, when applied to concrete for underground power equipment, can have an effect of improving strength, durability, and life due to excellent crack control properties, and can be applied more effectively, and precast. When applied to the concrete, the effect of improving the roughness and fastness can be applied more effectively, thereby realizing an excellent economic advantage.

(A) Alpha type gypsum

The cement composite composition for shrinkage-controlled concrete of the present invention includes alpha-type hemihydrate gypsum. The alpha-type hemihydrate gypsum is not particularly limited as long as it is dehydrated in a wet state and converted to an alpha (α) type. By using the alpha-type gypsum, it is possible to provide a cement composite composition for shrink-controlled concrete having excellent high strength and fast-hardness, compared to the case of using a gypsum in a form other than the alpha-type gypsum.

In particular, the alpha-type hemihydrate gypsum is incorporated into cement, and when hydrated, it reacts with calcium aluminate and / or calcium silicate components in cement to promote the production of hydration products. Through this, the alpha-type hemihydrate gypsum can activate the initial hydration reaction, increase the amount of hydration products in the initial stage, realize an initial strength improvement effect, and reduce dry shrinkage caused by hydration of cement. In addition, the initial hydrate provides additional expansion property in addition to the shrinkage compensation effect to further improve the shrinkage compensation property and the shrinkage control effect by reducing tensile stress.

Specifically, the alpha-type hemihydrate gypsum may be a wet phase transition material of flue gas desulfurization gypsum. As described above, the alpha-type semi-gypsum phase-transferred from the flue gas desulfurization gypsum not only has a high alpha (α) type transition rate, but also has a more compact structure, so that it is possible to further improve the high strength of the cement composite composition for shrink-controlled concrete, as well as non-shrinkability. , It can further improve the quick-hardening, roughness, and initial strength enhancement effect. In addition, sulfur, metal elements and / or metal oxides among the flue gases included in the flue gas desulfurization process promote reactivity in the process of hydration reaction, curing reaction, etc., shorten the setting time, and relieve tensile stress. .

In addition, flue gas desulfurization gypsum is a by-product of thermal power generation, so it has low cost and excellent material supply and demand, so it can not only lower the process cost of products used as raw materials, but also economic and eco-friendly treatment methods for industrial waste. There is an advantage that can be utilized as.

The conditions for wet phase transition of the flue gas desulfurization gypsum are not particularly limited, but may be, for example, reacting under conditions of 150 ° C to 200 ° C while applying pressure in a water vapor environment or an aqueous solution. Under these wet phase transition conditions, the phase transition material of the flue gas desulfurization gypsum can be more closely transferred to the crystal structure, thereby providing an alpha-type hemihydrate gypsum having superior strength.

The degree of powder of the alpha-type hemihydrate gypsum is not particularly limited, but may be specifically 1,300 cm ² / g to 1,500 cm ² / g. Within the above range, the alpha-type gypsum is more suitable for the alpha-type gypsum to additionally serve as an expander, and the effect of relieving stress by reducing micro voids inside the hydraulic material can be further improved. . In this case, not only the shrinkage rate of the concrete material is further reduced, but also the compressive strength can be further improved.

The alpha-type hemihydrate gypsum is not particularly limited, but the initial setting time is 6 minutes to 10 minutes, the final setting time is 15 minutes to 21 minutes, the moisture content is less than 0.15%, the expansion rate is less than 0.5%, and the daily wet strength is 25 MPa. Excess, the drying strength may be greater than 60MPa. In this case, the shrinkage control type of the cement composite composition for concrete is further improved in shrinkage and fastness, and heat insulation, heat retention, antibacterial property, humidity control property and deodorization property may be more excellent.

The content of the alpha-type hemihydrate gypsum may be included in 3 wt% to 16 wt%, specifically 4 wt% to 6 wt% in the cement composite composition for shrinkage control concrete. Within the above range, the shrinkage control effect by reducing the tensile stress and the effect as an expansion agent act in combination, and thus the crack prevention effect of the cement composite composition for shrinkage control type concrete is more excellent, thereby increasing durability and long life.

When the content of the alpha-type hemihydrate gypsum is less than 3% by weight, it is difficult to implement the initial strength-enhancing effect and excellent shrinkage control properties, and when it exceeds 16% by weight, a decrease in flowability due to material separation occurs.

(B) Anhydrous gypsum

The shrinkage-control type concrete cement composite composition of the present invention includes anhydrous gypsum. The anhydrous gypsum is not particularly limited as long as it is a gypsum anhydride containing calcium sulfate as a main component. By using the anhydrous gypsum, the fluidity is improved, the material separation phenomenon is effectively reduced, and it is possible to provide a cement composite composition for shrink-controlled concrete having excellent roughness and fast-hardness.

In particular, the anhydrous gypsum acts in combination with the above-mentioned alpha-type hemihydrate gypsum to promote the production of hydration products during hydration, and increase the amount of hydration products in the initial stage to realize coarse and quick stiffness. It is possible to improve the fluidity while increasing the degree of formation of the initial slump.

In addition, the anhydrous gypsum can further improve the shrinkage control effect of shrinkage compensation characteristics and tensile stress reduction of the cement composite composition for shrinkage control type concrete by acting as an expanding agent.

Specifically, the anhydrous gypsum may be plastic anhydride of crystalline gypsum, plastic anhydride of hemi gypsum, or anhydride of Busan gypsum. More specifically, the anhydrous gypsum may be Ⅲ type, Ⅱ type, Ⅰ type. When using type III as the anhydrous plaster, for example, the hydration property of a concrete material can be further improved, and when using type II, roughness can be further improved, and when using type I, compressive strength Can be further improved.

The powder level of the anhydrous gypsum is not particularly limited, but may be 1,000 cm ² / g to 5,000 cm ² / g, specifically 1,300 cm ² / g to 1,500 cm ² / g. Within this range, the anhydrous gypsum is more suitable to perform the role of an expanding agent, and the effect of relieving stress by reducing the micro voids inside the hydraulic material can be further improved. In this case, not only the shrinkage rate of the concrete material is further reduced, but also the compressive strength can be further improved.

The content of the anhydrous gypsum may be included in 0.1% to 10% by weight, specifically 1% to 5% by weight of the cement composite composition for shrink-controlled concrete. Within the above range, the strength of the shrinkage-controlled concrete cement composite composition is improved by further improving the roughness and fast-resistance and increasing the degree of formation of the initial slump, while the shrinkage control effect by reducing the tensile stress and the effect as the expansion agent act in combination. The effect and crack prevention effect can be further increased.

The content of the anhydrous gypsum may be included in 0.1% to 10% by weight, specifically 1% to 5% by weight of the cement composite composition for shrink-controlled concrete. Within the above range, the strength of the shrinkage-controlled concrete cement composite composition is improved by further improving the roughness and fast-resistance and increasing the degree of formation of the initial slump, while the shrinkage control effect by reducing the tensile stress and the effect as the expansion agent act in combination. The effect and crack prevention effect can be further increased.

When the content of the anhydrous gypsum is less than 0.1% by weight, the effect of reducing shrinkage and condensation is negligible, and when it is more than 10% by weight, the strength is lowered and the production cost is excessively improved, so that economic efficiency may be lowered.

The anhydrous gypsum and the aforementioned alpha-type gypsum plaster may be included in a weight ratio of 1: 0.1 to 1: 6, specifically 1: 2 to 1: 5.5, and more specifically 1: 3 to 1: 5.3. In this case, the alpha-type gypsum plaster and the anhydrite plaster work in combination to secure the ease of air shortening, thereby further improving the initial strength enhancement and rapid-hardening, while further improving the shrinkage of the shrinkage-control type concrete cement composite composition. Both the coarse stiffness, fast stiffness and setting time control effects are compatible, and the fluidity can be further improved.

(C) lime

The cement composite composition for shrink-controlled concrete of the present invention includes lime. The lime is not particularly limited as long as it can be used for cement. By using the lime, it is possible to provide a cement composite composition for shrink-controlled concrete having improved rigidity and fluidity, effectively reducing material separation, and having excellent high strength.

In particular, the lime acts in combination with the above-mentioned alpha-type hemihydrate gypsum and anhydrous gypsum to improve the fluidity that can be excessively reduced during hydration when water is mixed, improves workability, and cures shrinkage control concrete after curing The high strength and shrinkage control effect of the composite composition can be further improved.

The content of the lime may be included in 0.1% to 1% by weight of the cement composite composition for shrink-controlled concrete. Within the above range, the fluidity of the cement composite composition for shrink-controlled concrete may be further improved, and workability, flowability, shrinkage reduction, and compressive strength may be further improved.

When the content of the lime is less than 0.1% by weight, the effect of improving fluidity and strength is negligible, and when it is more than 1% by weight, strength and fluidity may be deteriorated.

(D) Auyne-based swelling agent

The cement composite composition for shrinkage-controlled concrete of the present invention includes a hauyne-based expander. The phosphorus-based expander is not particularly limited as long as it can be used for cement. By using the phosphorus-based swelling agent, it is possible to provide a shrinkage-control type concrete cement composite composition having a shrinkage compensation effect and a shrinkage control effect by reducing tensile stress.

In particular, when used together with the alpha-type hemihydrate gypsum phase-shifted from the above-described flue gas desulfurization gypsum, the phosphorus-based swelling agent reacts with sulfur, metal elements, and / or metal oxides contained in the alpha-type gypsum plaster to control shrinkage and crack as an expansion agent. There is an effect of further improving the reduction effect.

The content of the phosphorus-based expanding agent may be included in 0.1% to 3% by weight of the cement composite composition for shrink-controlled concrete. Within the above range, while the shrinkage reduction effect of the cement composite composition for shrinkage control type concrete is excellent, the occurrence of expansion cracks can be reduced, and the shrinkage control characteristics may be further improved.

When the content of the phosphorus-based is less than 0.1% by weight, the expansion effect is insignificant, and when it is more than 3% by weight, cracking occurs due to abnormal expansion, and the production cost is excessively improved, which may deteriorate economic efficiency.

(E) Cement

The cement composite composition for shrinkage-controlled concrete of the present invention contains cement as a binder. The cement is not particularly limited as long as it can be applied to concrete having high strength and ultra high strength in general. For example, it may include Portland cement, crude steel cement, super-steel cement, medium heat cement, sulfate resistant cement, blast furnace cement, fry ash cement, silica cement, polymer cement, or mixtures thereof.

In addition, the composition for concrete may additionally include blast furnace slack, fry ash, silica fume, etc. as a hydraulic material other than cement.

In addition, the composition for concrete may further include other admixtures to improve additional properties.

The cement may be included in 70 to 96.7% by weight of cement in the cement composite composition for shrink-controlled concrete. Within the above range, the above-described alpha-type hemihydrate gypsum; Anhydrite; lime; And a phosphorus-based swelling agent; the composite acts to realize remarkably excellent strength and adhesion of concrete, and can improve volume reduction compensation characteristics, flowability, shrinkage reduction, and compressive strength.

Method for manufacturing shrinkage-concrete concrete composites

Another embodiment of the present invention is an alpha-type hemihydrate gypsum; Anhydrite; lime; Auxinic expanders; And cement; comprising the mixing, relates to a method for producing a cement composite composition for the above-described shrinkage control type concrete.

The method of mixing each component of the cement composite composition for shrinkage-controlled concrete is not particularly limited, and content known in the related art may be applied.

The shrinkage control type cement composite composition for concrete is 3% to 16% by weight of alpha-type gypsum; 0.1% to 10% by weight of anhydrous gypsum; 0.1 to 1% by weight of lime; 0.1 to 3% by weight of the phosphorus-based expanding agent; And 70% to 96.7% by weight of cement; It may include. In this case, when only one of these components is added to the cement, it is possible to implement a volume reduction compensation property, flowability, shrinkage reduction, and compressive strength of concrete that are significantly superior.

The method of manufacturing the cement composite composition for shrinkage-controlled concrete includes the alpha-type hemihydrate gypsum; Anhydrite; lime; Auxinic expanders; And it may further include a process of powdering each before the whole cement is mixed. At this time, the powdering method is not particularly limited, and content known in the related art may be applied.

In one embodiment, the alpha-type hemihydrate gypsum can be mixed with the whole component after being powdered to 1,300 cm ² / g to 1,500 cm ² / g. In this case, the alpha-type gypsum is more suitable for the alpha-type gypsum to additionally act as an expander, and the effect of relieving stress by reducing the micro voids in the hydraulic material can be further improved.

In another embodiment, the anhydrous gypsum may be powdered to 1,000 cm ² / g to 5,000 cm ² / g and then mixed with the entire component. In this case, the anhydrous gypsum has more suitable properties to perform the role of an expanding agent, and the effect of relieving stress by reducing micro voids inside the hydraulic material can be further improved.

Concrete mortar composition

Another embodiment of the present invention is the above-mentioned shrinkage control type cement composite composition for concrete; And fine aggregate; relates to a mortar composition comprising a weight ratio of 1: 1 to 1: 3. Within the above range, excellent volume reduction compensation characteristics are realized, the shrinkage control effect of reducing tensile stress is improved, flowability, shrinkage reduction and compressive strength are excellent, non-shrinkage, fast-hardness, roughness, and high strength , It is possible to provide a mortar composition excellent in initial strength enhancement effect, heat insulation, heat retention, antibacterial, humidity control and deodorization.

The fine aggregate is not particularly limited. For example, it may be KS standard yarn. In this case, the high strength of the concrete material produced by the mortar composition can be further improved.

The additive may further include 1 to 10 parts by weight of the additive based on 100 parts by weight of the cement composite composition for shrink control. In this case, the non-shrinking property of the concrete material prepared by the mortar composition, fastness, roughness, high strength, initial strength enhancement effect, heat insulation, heat retention, antibacterial, humidity control and deodorization can be further improved.

The additive may be at least one of AE water reducing agent, fluidizing agent, high performance water reducing agent, accelerator, retarding agent, rapid setting agent, waterproofing agent, antirust agent, water-in-water separating agent, repair agent, anti-freezing agent and antifoaming agent.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is provided as a preferred example of the present invention and cannot be interpreted as limiting the present invention by any means. The contents not described herein will be sufficiently technically inferred by those skilled in the art, and thus the description thereof will be omitted.

The components used in the following Examples and Comparative Examples are as follows.

end. Cement composite composition ingredients

(A) Alpha type gypsum plaster: 1,400 cm ² / g of powder (Manufacturer: Yousung Tech, Product name: Alpha100

(B) Anhydrous gypsum: Powderiness 1,350 cm ² / g (Manufacturer: Yusung Tech, product name: HS-1000)

(C) Lime: fineness 2,200 cm ² / g (manufacturer: Kwangsung Chemical, product name: S200)

(D) Aouin expansion agent: sulfur content 2.5%, (manufacturer: DENCA, product name: CSA-1000)

(E) Cement: Portland cement (manufacturer: Ssangyong Cement, product name: 1 type OPC)

I. Mortar composition ingredients

(a) Fine aggregate: KS standard company (manufacturer: Jumunjin Co., Ltd., product name: Jumunjin standard company)

Examples 1 to 4 and Comparative Example 1

Preparation of shrinkage-controlled concrete cement composite composition

Alpha type hemihydrate gypsum according to the content shown in Table 1 below; Anhydrite; lime; Auxinic expanders; And cement; The mixture was divided into Examples and Comparative Examples to prepare a cement composite composition for shrinkage-controlled concrete.

Preparation of mortar composition for concrete

According to the contents shown in Table 1 below, the cement composite composition for shrink-controlled concrete prepared earlier and the fine aggregate were mixed to prepare a mortar composition according to Examples and Comparative Examples.

ingredient
(Parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Alpha type gypsum 3 6 9 12 16 0 17 Gypsum 3 3 3 3 3 3 3 Alpha type gypsum plaster: anhydrous plaster 1: 1 2: 1 3: 1 4: 1 5.3: 1 0 5.6: 1 lime One One One One One One One Aouin expanding agent 2 2 2 2 2 2 2 cement 91 88 85 82 78 94 77 Sum 100 100 100 100 100 100 100 Fine aggregate 245 245 245 245 245 245 245

<Physical property evaluation method>

 (1) Evaluation of flowability: After adding 49.4 weight ratio of water to the mortar compositions prepared in Examples and Comparative Examples, they were thoroughly mixed and measured according to the measurement method of KS F 2402. Table 2 shows the results.

(2) Evaluation of setting time: After adding 49.4 weight ratio of water to the mortar compositions prepared in Examples and Comparative Examples, they were thoroughly mixed and measured according to the measurement method of KSF 2436. Table 3 shows the results.

(3) Compressive strength evaluation

After adding 49.4 weight ratio of water to the mortar compositions prepared in Examples and Comparative Examples, after mixing thoroughly and curing, to prepare a specimen for compressive strength measurement (25 mmХ25 mmХ25 mm), 3 days after regeneration according to KS F 2405 , 7 days, 28 days after the compression strength was evaluated. Table 4 shows the results.

(4) Evaluation of shrinkage strain

After adding 49.4 wt. It was measured according to. As for the value, the value of the initial construction body is set to 0, "-" indicates a contraction value (unit: 10 ^-6 mm), and "+" indicates an expansion value (unit: 10 ^-6 mm). The results are shown in FIG. 1.

<Results of physical property evaluation>

(1) Flow evaluation

As can be seen through Table 2, Examples 1 to 5 of the present invention was excellent in flowability. On the other hand, Comparative Example 1 without alpha-type gypsum plaster had low flow, material separation occurred, and material in Comparative Example 2 containing alpha-type gypsum in an amount exceeding the scope of claim 1 of the present invention. It was confirmed that the separation phenomenon occurred. Through this, it can be seen that Examples 1 to 5 of the present invention are excellent in flowability and material separation resistance, while Comparative Examples 1 and 2 have low material separation resistance and sufficiently improve durability.

Flow value
(mm) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Primary 180 175 180 175 180 170 185 Secondary 175 180 175 180 175 175 190 3rd 175 175 170 175 185 165 180 Separation of materials radish radish radish radish radish U U

(2) Evaluation of setting time

As can be seen through Table 3, Examples 1 to 5 of the present invention had excellent setting time of 500 minutes or less. On the other hand, Comparative Example 1, which did not include alpha-type half-water gypsum, and Comparative Example 2, which contained an alpha-type half-water gypsum in an amount exceeding the scope of claim 1 of the present invention, had a long termination time, thereby realizing rapid stiffness, which is relatively effective in expressing strength. The following difficulties were confirmed.

(In Table 3, the fast-hardness was evaluated as excellent when the condensation state measured by the mortar intrusion resistance meter after 500 minutes elapsed after the start of hardening was sufficient and the intrusion resistance was insufficient and no trace of intrusion occurred. If insufficient traces remain due to insufficient penetration, it was evaluated as normal, and if penetration was not difficult because of little resistance to penetration, it was evaluated as defective.)

Setting time Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 closing 460 minutes 425 minutes 362 minutes 294 minutes 275 502 minutes 505 Fast-paced Great Great Great Great Great usually usually

(3) Compressive strength evaluation

As can be seen through Table 4, Examples 1 to 5 of the present invention has a small reduction in compressive strength according to the age of aging, while the compressive strength is excellent, Comparative Examples 1 and Alpha that do not include alpha-type hemihydrate gypsum Comparative Example 2 containing the mold half-water gypsum in an amount exceeding the scope of the present invention claim 1 was confirmed that the compressive strength is relatively low.

Compressive strength
(MPa) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 3 days of age 16.3 18.4 19.7 17.5 17.3 16.2 16.1 7 days of age 25.8 27.9 28.4 25.9 25.5 25.4 23.7 28 days of age 34.2 36.5 38.0 34.5 34.7 33.6 31.2

(4) Length change rate evaluation

As can be seen through Figure 1, Examples 1 to 4 of the present invention has a low rate of change in length according to age, and has excellent shrink control characteristics, whereas Comparative Example 1 without alpha-type gypsum has a length change rate. It was confirmed that the high shrinkage control characteristics were low.

As can be seen from the evaluation of the examples and comparative examples, the present invention is an alpha-type hemihydrate gypsum; Anhydrite; lime; Auxinic expanders; And cement; It can be seen that a mortar composition excellent in flowability, shrinkage reduction, and compressive strength, and a concrete material prepared therefrom can be provided through a cement composite composition for shrink-controlled concrete comprising a.

On the other hand, when the alpha-type gypsum is not included as in Comparative Example 1 or the alpha-type gypsum is included in an amount exceeding the range of claim 1 of the present invention as in Comparative Example 2, flowability, rapid-hardness, strength development and shrinkage The difficulty in exerting control characteristics was confirmed.

Claims (10)

Alpha type gypsum plaster 3% to 16% by weight;
0.1% to 10% by weight of anhydrous gypsum;
0.1 to 1% by weight of lime;
0.1 to 3% by weight of the phosphorus-based expanding agent; And
Cement 70% to 96.7% by weight; Including,
The weight ratio of the anhydrous gypsum and the alpha-type hemihydrate gypsum is 1: 2 to 1: 5.3,
The anhydrous gypsum is a cement composite composition for shrink-controlled concrete having a powder level of 1,000 cm ² / g to 1,500 cm ² / g.
According to claim 1,
The alpha-type hemihydrate gypsum is a wet phase changer of the flue gas desulfurization gypsum, a cement composite composition for shrinkage control type concrete.
According to claim 1,
The alpha-type gypsum plaster has a powder composite of 1,300 cm ² / g to 1,500 cm ² / g of a shrinkage-controlled concrete cement composite composition.
delete delete Alpha type gypsum plaster 3% to 16% by weight; 0.1% to 10% by weight of anhydrous gypsum; 0.1 to 1% by weight of lime; 0.1 to 3% by weight of the phosphorus-based expanding agent; And 70% to 96.7% by weight of cement; 1, wherein the weight ratio of the anhydrous gypsum and the alpha-type hemihydrate gypsum is 1: 2 to 1: 5.3, and the anhydrous gypsum has a powderiness of 1,000 cm ² / g to 1,500 cm ² / g. Method for producing a cement composite composition for shrink-controlled concrete according to the.
The method of claim 6,
The alpha-type hemihydrate gypsum is a wet phase transition of the flue gas desulfurization gypsum shrink control type cement composite composition for concrete.
delete The cement composite composition for shrink-controlled concrete according to claim 1; And fine aggregate; mortar composition comprising a weight ratio of 1: 1 to 1: 3.
The method of claim 9,
1 to 10 parts by weight of the additive based on 100 parts by weight of the cement composite composition for the shrinkage-controlled concrete further comprises,
The additive is a mortar composition of at least one of AE water reducing agent, fluidizing agent, high performance water reducing agent, accelerator, retarding agent, rapid setting agent, waterproofing agent, antirust agent, water-in-water separating agent, repair agent, anti-freezing agent and antifoaming agent.

Images