KR20180003272A - flowable fills using fly ash of cogeneration plant - Google Patents

Abstract

The present invention relates to a fluidized filler composition using fly ash generated from a combined heat and power plant, and more specifically, to a fluidized filler composition in a zero compacting method which makes fly ash, which can be used as a filler for filling in pipes, a back of a structure, sinkhole, a void or abandoned mines, and is hydraulic because generated from a combined heat and power plant, as a base material, and adjusts mixing ratios of materials to be easy to control strength and condensation time and a unit weight. The fluidized filler composition using fly ash generated from a combined heat and power plant of the present invention comprises: 30-80 wt% of a first fly ash; 1-40 wt% of any one strength modifier selected among cement and blast furnace slag; 1-30 wt% of any one condensation adjusting agent selected among anhydrous gypsum, hemihydrate, and a second fly ash; and 1-50 wt% of a unit weight adjusting agent selected among foaming agents and aggregate. The first fly ash is generated from a combined heat and power plant which burns pulverized coal by adding limestone.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized filler composition using fly ash generated in a cogeneration power plant,

The present invention relates to a fluidized filler composition using fly ash generated in a cogeneration power plant, and more particularly, to a fluidized filler composition using a fly ash generated from a cogeneration power plant, and more particularly, The present invention relates to a fluidized filler composition which is easy to control strength, coagulation time and unit weight by using fly ash as a base material and controlling the compounding ratio of materials.

Generally, in excavation and restoration works of civil engineering works, it is necessary to re-fill up soil after installing pipelines or underground facilities. It is difficult to communicate traffic when performing excavation repair works, complaints around construction sites, Therefore, the excavation restoration construction method is standardized.

In Korea, it is difficult to carry out high quality construction due to the characteristics of the process of completing the construction in order to minimize the traffic flow and the inconvenience of nearby residents. Because of the insufficient construction time, the foundation of the pipe and the subsidence of the subsurface are insufficient, and additional settlement occurs due to the characteristics of the subsurface slip, so that cracks may occur along the excavated part after the resurfacing.

Generally, when rewinding, it is necessary to use sand and excavated soil to compose, but it is often the case that the field is narrow and the machine or manpower can not be compromised. Also, even if compaction is performed, a settlement of 5% or more occurs, and it is troublesome to perform the filling operation with a subsequent operation.

 When the pipe is filled, the sand is filled, but when the groundwater flow is present, the sand is lost due to the influence of the scour and the sinking or landing phenomenon occurs. As the pipeline construction uses roads, it is required to complete the construction as soon as possible and filler materials that do not cause loss of filler due to subsidence and groundwater.

  When backfilling or filling with soil or sand, settlement occurs and there is a possibility of sinking due to the influence of scour. In addition, there is a disadvantage that the strength, the setting time and the unit weight can not be artificially controlled.

 In order to reduce the backfill or the earth pressure of the structure, the weight of the filler should be controlled to be low, and a pipe with a high unit weight and a low slump is required when the pipe is installed. In addition, if re-excavation is required depending on the application, a filler having functions such as lowering the strength so as to excavate with manpower or equipment or adjusting the strength when excavation is unnecessary is needed.

Thus, there is a demand for a fluidized filler which can control the mixing ratio of the material, the strength, the setting time, and the unit weight.

Korean Registered Patent No. 10-1146339: Non-compaction free vibration-free fluidized filler

The present invention can be used as a filling material such as pipe filling, structure backfill, soil off, sinkhole filling, cavity or abandoned mine, and it is produced from a cogeneration power plant and has hydraulically controlled fly ash as a base material. The present invention has been made in view of the above problems, and it is an object of the present invention to provide a fluidized filler composition which is easy to control the setting time and unit weight.

In order to accomplish the above object, the present invention provides a fluidized filler composition using fly ash generated from a cogeneration plant of the present invention comprises 30 to 80% by weight of a first fly ash, 1 to 40% by weight of any one of strength modifiers selected from cement and blast furnace slag, And 1 to 30% by weight of any one of the coagulation control agents selected from anhydrous gypsum and semi-gypsum and second fly ash, and 1 to 50% by weight of any one unit weight regulator selected from foaming agents and aggregates, Fly ash is generated from a coal-fired power plant that burns coal with pulverized coal.

The first fly ash powder has a water solubility of 3000 to 5000 cm2 / g and a calcium oxide (CaO) content of 20 to 50% by weight.

The fluidized filler composition is characterized by being capable of controlling the content of each material to adjust the strength to 0.3 to 3 Mpa, the setting time to 30 minutes to 6 hours, and the unit weight to 0.3 to 2.5 t / m ³ .

As described above, according to the present invention, it is easy to control the strength, the setting time and the unit weight by controlling the blending ratio of the material using fly ash as a base material, which is generated from a cogeneration power plant and has hydraulic properties.

The fluidized filler composition of the present invention has a faster condensation time than the conventional sand or cement filler, shortening the construction time and facilitating the strength control according to the excavation, which is advantageous in reducing the construction cost. In addition, since the unit weight can be adjusted artificially, it is easy to construct by quickly collapsing where the earth pressure reduction is required.

Therefore, the fluidized filler composition of the present invention can be usefully used as a filler such as a pipe filler, a structure backfill, a ground cover or a sinkhole filler, a cavity or an abandoned mine.

Hereinafter, a fluidized filler composition using fly ash generated from a cogeneration power plant according to a preferred embodiment of the present invention will be described in detail.

The fluidized filler composition according to an embodiment of the present invention contains a first fly ash, an intensity modifier, a curing regulator, and a unit weight regulator. For example, it may contain 30 to 80% by weight of the first fly ash, 1 to 40% by weight of the strength adjusting agent, 1 to 30% by weight of the curing regulating agent, and 1 to 50% by weight of the unit weight adjusting agent.

The first fly ash refers to coal ash produced as a by-product during coal combustion. The first fly ash is a fly ash collected in the dust collecting facility during the coal combustion process. Preferably, the present invention uses fly ash generated in a cogeneration power plant in which limestone is added to pulverized coal pulverized coal to burn coal as a first fly ash. Therefore, in the present specification, the first fly ash means coal ash collected in a dust collecting facility of a cogeneration power plant in which limestone is added to pulverized coal.

The coal ash generated in Korea can be divided into two types. The first is F-grade coal ash produced by using bituminous coal as raw coal at a high combustion temperature of 1100 ~ 1300 ℃, and the second is a coal-fired power plant. Is a C-grade coal ash produced from coal by using bituminous coal and lignite as raw materials and adding limestone powder to the raw coal.

In the case of coal ash produced by burning only pure bituminous coal such as F-grade coal ash generated in a general thermal power plant, the calcium oxide (CaO) content is 1 to 5% by weight or less and since bituminous coal is burned in a high- It is produced from coal ash with particles. On the other hand, in the case of C-grade coal ash produced in a cogeneration plant, it is irregular particles because it is burned at a low temperature and is composed mostly of crystalline material. Since limestone powder is added to the raw coal and the content of calcium oxide (CaO) Or more. Table 1 below shows the chemical composition of the fly ash produced in the cogeneration plant and the fly ash produced in the thermal power plant.

Item Content (wt%) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ O K ₂ O SO ₃ Combined heat and power plant fly ash 31.6 16.0 5.66 32.7 3.52 1.08 1.34 6.24 thermal power plant
Fly ash 62.8 21.1 5.95 3.60 1.13 0.98 1.80 0.59

As shown in the following Table 1, fly ash produced in a general thermal power plant has a high SiO ₂ content but a low CaO content, indicating a potential hydraulic property lacking an alkaline component for strength reaction. However, fly ash produced in a cogeneration plant has a pozzolanic substance and CaO content Is high and contains an alkali stimulant. Therefore, it has a characteristic of showing hardness of hardness by itself.

The first fly ash, which is coal ash collected in the dust collecting facility of the cogeneration power plant where limestone is added to the pulverized coal, has a powder content of 3,000 to 5,000 cm 2 / g and a CaO content of 20 wt% or more, for example, 20 to 50 wt% desirable.

The first fly ash is in the form of a fine powder and is used as a main material of the fluidized filler composition because it has the characteristic of exhibiting hydration resistance upon self-hydration reaction upon contact with water. The first fly ash is an industrial by-product generated from a cogeneration power plant, and when used as a fluidized filler composition, it is effective to save material costs and recycle industrial by-products as useful materials.

As the strength modifier, any one selected from cement and slag may be used. Blast furnace slag powder can be used as the slag. The strength modifier is for controlling the compressive strength of the fluidized filler composition, and it is preferable that the strength modifier is added in an amount of 1 to 40 wt% so that the compressive strength can be adjusted to 0.3 to 3 MPa. If the content of the strength adjusting material is less than 1% by weight, the strength of the fluidized filler composition is weakened and the function of the filler can not be exhibited. If it exceeds 40% by weight, the strength becomes higher than necessary and the construction cost increases.

As the setting agent for curing, any one selected from anhydrous gypsum and semi-gypsum and second fly ash is used. The coagulation controlling agent is for controlling the coagulation time of the fluidized filler composition, and the coagulation controlling agent is preferably added in an amount of 1 to 30% by weight.

The second fly ash refers to coal ash collected in a dust collecting facility of a thermal power plant. This second fly ash has different properties from the first fly ash mentioned above. The second fly ash has a high SiO ₂ content but a low CaO content and thus has a latent hydraulic property which lacks alkaline components for strength reaction.

The use of non-gypsum or semi-gypsum as a coagulation modifier can shorten the setting time. When it is necessary to increase the setting time, a second fly ash having long-term strength development is used as a curing agent.

The unit weight control material is used for controlling the weight per unit volume of the fluidized filler composition. Preferably, the unit weight adjusting material is contained in an amount of 1 to 50% by weight in order to control the unit weight. A unit weight adjusting material is used as either a foaming agent or an aggregate. As a foaming agent, a conventional foaming agent for concrete can be used. And natural aggregate such as sand or gravel or slag aggregate can be used as aggregate.

In order to reduce the unit weight to reduce the earth pressure, it is preferable to add a foaming agent as a unit weight adjusting material, and it is advantageous to use a slump having a low slump and a high unit weight at the time of pipeline installation, desirable.

On the other hand, the present invention can add alumina sulfate as a pH adjusting agent.

As described above, the present invention is characterized in that it comprises 30 to 80% by weight of the first fly ash, 1 to 40% by weight of any one of the strength modifiers selected from cement and blast furnace slag, and one of anhydrous gypsum and semi- 1 to 30% by weight of a coagulation controlling agent of the present invention and 1 to 50% by weight of a unit weight adjusting material selected from a foam stabilizer and an aggregate may be mixed to prepare a fluidized filler composition.

The fluidized filler composition of the present invention can adjust the content of each material to 0.3 to 3 MPa, the setting time is 30 minutes to 6 hours, and the unit weight is 0.3 to 2.5 t / m ³ . Further, the present invention can easily adjust the strength, the setting time, and the unit weight according to the kind of the strength adjusting agent, the type of the coagulating agent, and the type of the unit weight adjusting agent.

The fluidized filler composition of the present invention is mixed with water at a suitable ratio (in the range of 100 to 230 mm of slump) and is used as filler such as pipe filler, backfill of structure, ground cover or sinkhole filler, cavity or abandoned light.

Hereinafter, a method of producing the fluidized filler composition of the present invention will be described by way of examples. However, the following examples are intended to illustrate the present invention in detail, and the scope of the present invention is not limited to the following examples.

(Example)

(Portland cement, Ssangyong cement), slag powder (blast furnace slag powder, cement and powder, 4000 ~ 6000cm ² / g) as the strength adjusting agent, and a first fly ash having a calcium oxide content of 32.7 wt% A second fly ash having a calcium content of 3.60 wt%, and a slag aggregate (ferronickel slag, Innosand, particle size 5 to 10 mm) as a unit weight adjusting material were mixed to prepare a fluidized filler composition.

The first was used for fly ash with fly ash (Hanwha energy, powder ² / g even 3000 ~ 4500cm) generated from combined heat and power plant, the second fly ash (HADONG thermal power plant, fineness 3000 ~ 4500cm generated from the power plant to the fly ash ² / g) was used.

As shown in Table 2 below, the fluidized filler composition was prepared by controlling the mixing ratio of the cement or slag powder as the strength control material, the second fly ash as the coagulation control material, and the slag aggregate as the unit weight control material, using the first fly ash as the main material After 1.2 times (by volume) water was mixed and cured. After 7 days of curing, the uniaxial compressive strength was measured by KS F 2405 test method, the setting time was measured by KS L ISO 9597 test method, and the unit weight was measured by electronic scales.

The composition of the fluidized filler according to the composition of each material and the experimental results thereof are shown in Table 2 below.

First fly ash
(wt%) Strength modifier Curing modifier Unit weight adjusting material result cement
(wt%) Slag powder (wt%) Second fly ash (wt%) Slag
Aggregate (wt%) Compressive strength
(MPa) Setting time Unit weight
(t / m ³ )


Intensity control



65 5 - 10 20 0.525 60 10 - 10 20 0.797 50 20 - 10 20 1.86 40 30 - 10 20 2.82 65 - 5 10 20 0.75 60 - 10 10 20 1.47 50 - 20 10 20 3.01 40 - 30 10 20 3.75
Setting time
50 10 - 20 20 30 minutes 45 10 - 25 20 1 hours 40 10 - 30 20 3 hours
Unit weight
65 10 - 10 15 1.84 55 10 - 10 25 1.97 40 10 - 10 40 2.05

Referring to Table 2, the higher the content of the strength modifier, the more the compressive strength was increased. In case of using the same amount of strength modifier, the compressive strength of slag powder was higher than that of cement. When the compressive strength is 2.1 MPa or more, the addition amount of cement is about 30% and the addition amount of slag powder is about 20% at the site where excavation is not required after the fluidized filler is applied.

And, as the content of curing agent increased, the curing time was delayed. The flocculation time of the fluidized filler composition was usually from 30 minutes to 3 hours, and it was confirmed that the coagulation time could be controlled from 30 minutes to 3 hours by controlling the content of the coagulant.

And the unit weight increases as the content of the unit weight control material increases. If a pipeline is installed, the pipe may float due to buoyancy, so it is necessary to adjust the unit weight to a low slump. In this case, the unit weight can be increased by increasing the addition amount of the unit weight adjusting material.

As described above, the fluidized filler composition of the present invention is quick in condensation time and shortens the construction time compared to the existing sand or cement filling, and is easy to control the strength according to whether it is excavated, which is advantageous in cost reduction. In addition, since the unit weight can be adjusted artificially, it is easy to construct by quickly collapsing where the earth pressure reduction is required.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation.

Claims (3)

30 to 80% by weight of the first fly ash, 1 to 40% by weight of any one of the strength modifiers selected from cement and blast furnace slag, 1 to 30% by weight of any one of the coagulation controlling agents selected from anhydrite and hemihydrate gypsum and second fly ash %, And 1 to 50% by weight of a unit weight adjusting material selected from the group consisting of foaming agents and aggregates,
Wherein the first fly ash is generated from a cogeneration power plant in which limestone is added to the pulverized coal and burned. 2. The fluidized filler composition according to claim 1, wherein the first fly ash has a solubility in water of 3000 to 5000 cm < 2 > / g and a calcium oxide (CaO) content of 20 to 50 wt%. The fluidized filler composition according to claim 1, wherein the fluidized filler composition has a strength of 0.3 to 3 Mpa, a condensation time of 30 minutes to 6 hours, and a unit weight of 0.3 to 2.5 t / m ³ by controlling the content of each material. Composition.