KR101773760B1 - Superfluidity concrete composition comprising crushed-stone sludge - Google Patents

Abstract

The ultra-high-flow concrete composition for general strength containing a sludge sludge of the present invention comprises not less than 0% by weight and not more than 30% by weight of sludge sludge.

Description

TECHNICAL FIELD [0001] The present invention relates to a super-flow concrete composition for use in general strength containing rock salt sludge,

The present invention relates to a super flowable concrete composition for general strength with a stone sludge.

Concrete is used as the main material for civil engineering works or architectural structures such as dams, road pavements and bridges. Concrete may have different physical properties such as strength, fluidity and durability depending on the composition and content of the composition. In recent years, there has been an increase in demand for ultra-high-flow concrete having increased fluidity for superior workability, but it is disadvantageous in that the unit powder amount is high and expensive.

In general, concrete with superfluidity is also increased in strength. Therefore, a concrete that can increase the fluidity and adjust the strength as well as reduce the manufacturing cost is needed.

On the other hand, in Korea, the stone sludge produced more than 2.5 million tons per year is classified as waste, and it is costly to dispose of it through the waste disposal company when disposing. There have been a lot of researches on the use of fine particles as a dry state after drying and pulverization without discarding it but there is a disadvantage that economical efficiency is low due to cost and time of drying and grinding process. Therefore, there is a need for a method that can utilize such a stone sludge without drying and crushing process.

Prior art related to this is disclosed in Korean Patent Publication No. 1999-0064844.

An object of the present invention is to provide a super fluidized concrete composition for a general strength containing a stone sludge excellent in fluidity and workability.

Another object of the present invention is to provide a super fluidized concrete composition for general strength with a stone sludge capable of adjusting the strength and reducing the cost.

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

One aspect of the present invention relates to a super strength fluid concrete composition for general strength with a sludge sludge.

In an embodiment, the concrete composition comprises from 0 to 30 wt% or less of the stone sludge.

The abrasive sludge may have a water content of 150% to 300%.

The concrete composition may include more than 0 wt% of the stone sludge and 70 wt% or more and less than 100 wt% of the cement.

The concrete composition may have a slump flow of 500 mm or more.

The concrete composition may have a compressive strength of from 20 MPa to 50 MPa after 28 days of curing.

The concrete composition may further contain 5 to 50 parts by weight of fly ash or blast furnace slag with respect to 100 parts by weight of the total amount of the stone dust sludge and cement.

The concrete composition may further comprise 100 to 300 parts by weight of sand per 100 parts by weight of the total amount of the stone dust sludge and cement.

The present invention has an effect of providing a super fluidized concrete composition for general strength containing a stone sludge which is excellent in fluidity and workability as well as capable of adjusting the strength and reducing the cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a concrete V-rod test apparatus for measuring the relative speed of a concrete composition of the present invention. FIG.

As used herein, the term " stone sludge " means a stone sludge containing water as it is generated during the production of crushed aggregate without being subjected to a drying and grinding step, and may be used in the same meaning as "wet stone sludge ".

As used herein, the term "water content" means the ratio (%) of the weight (S) of dry stone sludge excluding water to the weight (W) of water contained in the wet stone sludge, Lt; / RTI >

[Formula 1]

Water content (%) = (S) / (W) x 100

(Where, S is the weight of the dry stone sludge in the wet stone sludge and W is the weight of the water contained in the stone sludge)

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the super-fluid concrete composition for general strength with a sludge sludge of the present invention will be described in detail.

The superconducting concrete composition for general strength containing a sludge sludge according to the present invention contains the sludge sludge in an amount of 0 to 30% by weight or less.

The above-mentioned stone dust sludge is contained in the concrete composition, and the flowability can be remarkably increased. Specifically, the stone dust sludge can reduce the bonding force between the concrete compositions such as cement and fly ash, thereby increasing the fluidity of the concrete composition.

In an embodiment, the concrete composition may have a slump flow of 500 mm or more and 1000 mm or less, specifically 500 mm or more and 800 mm or less, more specifically, 655 mm or more and 800 mm or less. Further, in the slump flow measurement, the time for the concrete to reach 500 mm from the center may be 6 to 10 seconds, specifically 8 to 10 seconds, more specifically 8 to 9 seconds. In the above-mentioned range, the concrete composition has an advantage of excellent workability since the compaction step can be omitted at the time of construction. The slump flow can be measured by the flow test method of KS F 2594 'concrete.

In addition, since the above-mentioned stone sludge has no pozzolanic reaction and latent hydraulic properties, it has an effect of controlling the strength of the ultrafluid concrete composition for ordinary strength. Particularly, the strength of the concrete composition can be appropriately adjusted to be used in fields or applications which do not require high strength. In this case, there is also an effect of improving the quality of concrete by improving the fluidity of general concrete while reducing the cost of producing concrete.

Specifically, the concrete composition containing the stone sludge may have a compressive strength after 28 days of hardening of 20 MPa to 50 MPa, specifically 20 MPa to 40 MPa. In the above range, the concrete composition not only maximizes the fluidity but also can appropriately control the strength to suit the intended use and the required strength.

The specimens were prepared from cylinders having a diameter of 100 mm or more and a diameter of 2 times the height according to KS F 2405. The specimens were subjected to a load such that the rate of increase of the compressive stress was 0.6 +/- 0.4 MPa per second in accordance with KS F 2405 , The average of the values calculated three times by the following formula 2 can be used as the compressive strength.

[Formula 2]

Fc (MPa) = P / A

(Where Fc is the compressive strength (MPa), P is the maximum load (N) applied, and A is the cross-sectional area (mm ² ) of the specimen contacted by the pressure plate.

The concrete composition may have a relative descending speed (1 / sec) of 18 / sec or less, specifically 5 / sec to 18 / sec, more specifically 10 / sec to 18 / sec. In the above-mentioned range, the concrete composition has an advantage of excellent workability since the compaction step can be omitted at the time of construction. The above relative lifting speed was measured by the V-rod testing device for concrete of FIG. 1, and the time until the bottom surface was observed was measured as the lifting time V _t (sec) Can be calculated.

[Formula 3]

Relative descent velocity (1 / sec) = 10 / V _t

(V _t in the formula (3) is the dropping time (sec)

The concrete composition may have a U-shaped charge higher difference (mm) of 5 mm to 25 mm, specifically 10 mm to 20 mm. The balance between flowability and compressive strength is excellent in the above range. The above-mentioned U-shaped charging high-level concrete was put into one side of a U-shaped charging tester in which three deformed reinforcing bars D13 were arranged at intervals of 50 mm in a central portion of a container having a height of 590 mm and a width of 280 mm. When the central partition was lifted, Height difference.

In an embodiment, the calcined sludge comprises 55 to 75% by weight of silicon oxide (SiO ₂ ), 10 to 30% by weight of alumina (Al ₂ O ₃ ), 2 to 20% by weight of potassium oxide (K ₂ O) %. ≪ / RTI > Within the above range, the flowability of the concrete composition is maximized and the strength can be appropriately adjusted to suit the intended use and the required strength.

In an embodiment, the abrasive sludge may comprise 0 to 30 wt.%, Specifically 10 to 30 wt.%, More specifically 15 to 25 wt.% Of the general strength super-flow concrete composition. In the above-mentioned range, the flowability of the concrete composition is remarkably increased, and there is an advantage that the chopping process can be omitted during the operation. Also, if necessary, the strength of the stone dust sludge can be appropriately adjusted to suit the intended use and the required strength of the super-flow concrete composition for ordinary strength.

Particularly, since the concrete composition of the present invention uses stone dust which contains water as it is generated in the production of crushed aggregate without being subjected to a drying and pulverizing process, the use of stone dust sludge is easy and the cost of the concrete composition is remarkably reduced It is effective.

The abrasive sludge may have a water content of 150% to 300%, specifically 200% to 300%, more particularly 220% to 280%. In the above range, the stone slurry can be applied as it is without any additional process, and the application of the stone slurry is easy, and the cost of the concrete composition is reduced.

The above-mentioned stone dust sludge may have a specific surface area of 3,500 cm ² / g to 9,000 cm ² / g. Within the above range, the strength can be appropriately adjusted to suit the purpose and the required strength of the concrete composition. The above-mentioned stone dust sludge may have a density of 2.0 g / cm ³ to 3.0 g / cm ³ , specifically 2.4 g / cm ³ to 2.8 g / cm ³ . Within the above range, the concrete composition is excellent in fluidity.

The concrete composition may include 0 to 30 wt% of stone dust, 70 wt% to less than 100 wt% of cement. In the above range, the concrete composition not only maximizes fluidity but also can maintain appropriate strength.

The cement to be used in the present invention is not particularly limited as long as it is a commonly used cement in the art, but specifically, it is possible to use special Portland cement, blast furnace slag cement, ultra fine powder cement and other special cements. For example, Portland cement can usually be used to maximize fluidity.

The cement may be contained in the concrete composition in an amount of 70 wt% to less than 100 wt%, specifically 70 wt% to 90 wt%, and more specifically, 75 wt% to 85 wt%. In the above range, the concrete composition not only satisfies the required quality such as strength and durability but also has excellent fluidity.

The cement powder may have a particle size of 3,000 cm ² / g to 6,500 cm ² / g. Within this range, the balance between the flowability and compressive strength of the concrete composition is excellent.

In an embodiment, the concrete composition may further comprise fly ash and / or blast furnace slag.

The fly ash used in the present invention is a coal ash collected by a dust collector during pulverized coal combustion. The spherical particle size is similar to that of cement, and alumina and silica are main components and used as a concrete admixture. When it is mixed with cement in proper quantity, it improves workability and mitigates hydration heat, and it is economical because it improves long-term strength and watertightness.

The fly ash according to the present invention can use fine pulverized fly ash, and the finely pulverized fly ash provides improved high strength and / or fluidity than using non-pulverized fly ash.

And fineness of the fly ash is 3,000 cm ² / g to 5,000 cm ² / g, specifically 3,000 cm ² / g to about 3,800cm ² / g, more specifically less than 3,700cm ² / g, the density was 1.5 g / cm ³ to 2.8 g / cm ³ , specifically 2.00 g / cm ³ to 2.30 g / cm ³ . The balance of compressive strength, flowability and durability is excellent in the above range.

The blast furnace slag used in the present invention is a slag generated when pig iron is made from iron ores in a furnace, and impurities other than iron can be used.

The fly ash and / or the blast furnace slag may be contained in an amount of 5 to 50 parts by weight, specifically 15 to 40 parts by weight, based on 100 parts by weight of the total amount of the stone mortar and cement. In the above range, the concrete composition is excellent in balance between fluidity and compressive strength.

The concrete composition may further comprise sand.

The sand may have a density of 2.20 g / cm ³ to 3.00 g / cm ³ , an absorption rate of 1.5% to 3%, and a granulation rate of 1 to 3. The sand may include 100 to 300 parts by weight, specifically 150 to 250 parts by weight based on 100 parts by weight of the total amount of the stone dust and cement. Within the above range, the flowability of the concrete composition is excellent.

The concrete composition may further include an aggregate.

The aggregate used in the present invention is a mineral material for construction which can be consolidated into a lump by a binder such as concrete, and is chemically stable. The aggregate refers to sand, gravel, basalt, osseite, basalt and other similar materials that are mixed with cement and water to produce a bridge, i.e., concrete for bridge packaging. The aggregate further comprises a basic rock carcass having a particle size of about 10 mm to 40 mm and an absorption rate of about 0.4% to 1.0% and / or a bauxite having a particle size of about 1 mm to 10 mm and an absorption rate of 5.10% to 5.70% can do. The aggregate may include a coarse aggregate, and the coarse aggregate refers to a coarse aggregate used in general concrete production.

The concrete composition may further contain 150 to 350 parts by weight, specifically 170 to 320 parts by weight of aggregate, based on 100 parts by weight of the total amount of the stone mortar and cement. Within the above range, the flowability of the concrete composition and the balance of compressive strength are excellent.

The concrete composition of the present invention may further comprise additives. For example, the additive may include one or more of a high performance water reducing agent, an expansion agent, a shrinkage reducing agent, an air entraining agent, a pigment, a filler, a defoamer, a dispersant, a surfactant, an antioxidant and a flow inhibitor.

Here, the high performance water reducing agent, the expansion agent, the shrinkage reducing agent, the air entraining agent, the pigment, the admixture, the filler, the defoaming agent, the dispersant, the surfactant, the antioxidant and / or the flow- .

The additive may be added in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the total amount of the stone dust sludge and the cement.

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

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

Example

The specifications of the components used in the following examples are as follows.

(A) Stone dust sludge: A stone dust sludge having a density of 2.72 g / cm ³ , a water content of 250% and a specific surface area of 5,500 cm ² / g was used.

(B) Cement: A normal Portland cement having a specific surface area (specific surface area) of 3,426 cm ² / g and a density of 3.14 g / cm ³ was used.

(C) Fly ash: Fly ash having a density of 2.15 g / cm ³ and a powder density (specific surface area) of 3,589 cm ² / g was used.

(D) Sand: Steel sand having a density of 2.58 g / cm < ³ >, a water absorption rate of 2.20% and a sanding rate of 2.37 was used.

(E) Aggregate (coarse aggregate): A fine aggregate having a density of 2.61 g / cm ³ , a water absorption rate of 1.80% and a granulation rate of 2.67 was mixed with a coarse aggregate having a density of 2.67 g / cm ³ , a water absorption rate of 1.69% and a granulation ratio of 6.91.

(F) Additive: High performance water reducing agent was used.

Comparative Example 1

A concrete composition comprising 50 parts by weight of water, 25 parts by weight of fly ash, 219 parts by weight of sand, 237 parts by weight of aggregate and 1.75 parts by weight of additives was prepared per 100 parts by weight of ordinary Portland cement.

Example 1

A concrete composition was prepared comprising 50 parts by weight of water, 25 parts by weight of fly ash, 219 parts by weight of sand, 237 parts by weight of aggregate and 1.75 parts by weight of additive per 100 parts by weight of 10% by weight of stone mortar sludge and 90% by weight of ordinary Portland cement .

Example 2

A concrete composition comprising 50 parts by weight of water, 25 parts by weight of fly ash, 219 parts by weight of sand, 237 parts by weight of aggregate and 1.75 parts by weight of additives was prepared per 100 parts by weight of 20% by weight of stone mortar sludge and 80% by weight of ordinary Portland cement .

Example 3

A concrete composition was prepared comprising 50 parts by weight of water, 25 parts by weight of fly ash, 219 parts by weight of sand, 237 parts by weight of aggregate and 1.75 parts by weight of additives, based on 100 parts by weight of 30% by weight of stone mortar sludge and 70% .

Property evaluation method

(1) Slump flow (unit: mm) and slump flow 500 mm reaching time (sec): The slump flow was measured by KS F 2594 'Flow Test Method of Concrete' and the time at which the concrete reached 500 mm from the center And the results are shown in Table 1 below.

(2) Compressive Strength (MPa): The compressive strength of a cylindrical specimen of Φ100 mm × 200 mm was prepared in accordance with KS F 2405, and the load was increased to 0.6 ± 0.4 MPa per second according to KS F 2405 , And the average of the values calculated three times according to the following formula 2 is shown in Table 1. < tb > < TABLE >

[Formula 2]

Fc (MPa) = P / A

(Where Fc is the compressive strength (MPa), P is the maximum load (N) applied, and A is the cross-sectional area (mm ² ) of the specimen contacted by the pressure plate.

(3) Relative dipping speed (1 / sec): The condition of the concrete in the examples and comparative examples was observed with a V-rod test device for concrete (refer to FIG. 1) _t , and the relative rate of descent was calculated by the following equation (3).

[Formula 3]

Relative descent velocity (1 / sec) = 10 / V _t

(V _t in the formula (3) is the dropping time (sec)

(4) U-shaped Charge Higher Difference (mm): Concrete of Examples and Comparative Examples were put into one side of a U-shaped filling test apparatus in which three deformed reinforcing bars D13 were arranged at intervals of 50 mm at the center of a container having a height of 590 mm and a width of 280 mm, Table 1 shows the difference in height between the two concrete surfaces when the central partition is lifted.

Comparative Example 1 Example 1 Example 2 Example 3 (A) (% by weight) 0 10 20 30 (B) (% by weight) 100 90 80 70 Slump Flow (mm) 650 655 680 685 Slump Flow 500mm reaching time (sec) 7 8 8 8 Relative descent speed (1 / sec) 19 17 18 16 U Type Higher charge (mm) 15 20 15 10 Compressive strength (MPa) 40.2 38.1 37.0 27.0

As shown in Table 1, it can be seen that the concrete composition of the example including the stone dust sludge is not only excellent in fluidity and workability but also can control the compressive strength by controlling the content of the sludge sludge. In addition, the stone dust sludge of the embodiment is used without being subjected to the drying and crushing processes, thereby reducing the cost.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (7)

From 0 to 30% by weight of cement sludge and from 70 to less than 100% by weight of cement,
And 100 to 300 parts by weight of sand relative to 100 parts by weight of the total amount of the above-mentioned stone dust sludge and cement,
Wherein the stone sludge has a water content of 150% to 300%.
delete delete The concrete composition of claim 1, wherein the concrete composition has a slump flow of at least 500 mm.
The concrete composition of claim 1, wherein the concrete composition has a compressive strength of 20 MPa to 50 MPa after 28 days of curing.
The concrete composition of claim 1, wherein the concrete composition further comprises 5 to 50 parts by weight of fly ash or blast furnace slag with respect to 100 parts by weight of the total amount of the stone sludge and cement.

delete

Images