KR102660956B1 - Eco-friendly low ph 2 component type grout composition - Google Patents

Abstract

The present invention relates to a two-component grout composition in which a first liquid, which is a quick-setting suspension, and a second liquid, which is an expandable suspension, excluding cement, are each prepared and then injected into the ground and simultaneously combined and mixed. Calcium aluminate and calcium sulfoaluminate By applying the first liquid, which contains nate as the main ingredient, and the second liquid, which contains blast furnace slag fine powder and circulating fluidized bed fly ash as the main ingredient but with the addition of cement kiln dust, it is possible to secure stable early strength and strongly suppress alkali elution. will be.
Through the present invention, alkali leaching can be effectively suppressed while securing the strength of the consolidated body, which is the basic performance of the grout material, and thus groundwater and soil contamination that may be caused by the construction of the grout material can be prevented.

Description

Eco-friendly low alkali two-component grout composition {ECO-FRIENDLY LOW PH 2 COMPONENT TYPE GROUT COMPOSITION}

The present invention relates to a two-component grout composition in which a first liquid, which is a quick-setting suspension, and a second liquid, which is an expandable suspension, excluding cement, are each prepared and then injected into the ground and simultaneously combined and mixed. Calcium aluminate and calcium sulfoaluminate By applying the first liquid, which contains nate as the main ingredient, and the second liquid, which contains blast furnace slag fine powder and circulating fluidized bed fly ash as the main ingredient but with the addition of cement kiln dust, it is possible to secure stable early strength and strongly suppress alkali elution. will be.

Grouting, also called grouting, is by injecting liquid fillers such as bentonite, water glass, cement, asphalt, mineral mixtures, or various resin-based compounds into cracks in the ground or building to induce hardening. This refers to a technique to reinforce or block the flow of groundwater.

In the construction industry, grouting is used in various fields such as reinforcing or improving the foundation or background of a structure, as well as suppressing groundwater outflow or artificially adjusting the groundwater level. Depending on the purpose of construction, grouting, ground improvement grouting, filling grouting, and reinforcement are used. It can be classified into grouting, etc., and can be classified into cavity grouting, crack grouting, void grouting, etc. depending on the injection location of the grout material.

As such, grouting can be classified in various ways depending on the purpose and object of application, but the basic mechanism is that the liquid injection material penetrates into the construction object and then hardens to reveal the desired strength, which is a key characteristic required during construction. Examples include fluidity before curing, curing speed, dissolution, strength and corrosion resistance after curing.

Double leaching property is a characteristic in which components in the injection material are dissolved or lost by groundwater, etc. during the curing process immediately after injection of the liquid injection material and leak out of the solidified body. If leaching property is poor and a large amount of effluent is generated, the grout solidified body itself. Not only does the basic performance such as strength and corrosion resistance seriously deteriorate, but it also causes serious contamination of the surrounding soil and groundwater.

In particular, cement, which is widely used as a grout material, has strong alkalinity, so serious alkali leaching phenomenon is inevitable when applied as a grout material. To avoid this, the amount of cement mixed into the material is reduced and various mineral fine powders are used. ) and various attempts have been made to control the gel time, which is the initial setting time of the grout material, and related prior art includes Patent No. 2023918.

Conventional alkali leaching-inhibiting grout materials, including Patent No. 2023918, induce rapid solidification rather than controlling the characteristics of the raw materials, or allow the solidification time to be adjusted according to ground conditions, thereby improving leaching properties while securing the desired strength. Focusing.

However, these conventional leaching-inhibiting grout materials basically did not completely exclude mixing of cement, so there was inevitably a limit to suppressing alkali leaching due to cement, which is a strongly alkaline material.

In particular, in order to overcome this poor leaching property, a large amount of expensive admixtures had to be mixed or super-consolidation had to be induced, which resulted in serious problems such as an inevitable increase in material costs and a decrease in constructability when performing related construction work.

In consideration of the above-mentioned problems, the present invention was created to completely exclude cement mixing in the grout material to suppress alkali leaching while also ensuring sufficient strength. The first liquid is a quick-setting suspension and the second liquid is an expandable suspension, respectively. In a two-component grout composition that is prepared and then injected into the ground and simultaneously combined and mixed at a ratio of 40% to 60% by weight of the first liquid and 40% to 60% by weight of the second liquid, the first liquid is the first powder. It is formed by mixing 20% to 30% by weight and 70% to 80% by weight of water, wherein the first powder contains 30% to 45% by weight of calcium aluminate, 8% to 20% by weight of calcium ferroaluminate, It is formed by mixing 40% to 50% by weight of anhydrous gypsum, 1% to 5% by weight of an aluminate-based hydration accelerator, and 0.1% to 1% by weight of an organic acid-based setting retardant, and the second liquid is second powder 30 It is formed by mixing % to 40% by weight and 60% to 70% by weight of water, and the second powder is 35% to 55% by weight of blast furnace slag fine powder, 25% to 45% by weight of circulating fluidized bed fly ash, and hydroxide. It is an eco-friendly, low-alkali two-component grout composition, characterized in that it is formed by mixing 5% to 10% by weight of potassium, 5% to 10% by weight of anhydrous gypsum, and 2% to 8% by weight of cement kiln dust.

In addition, the present invention provides an eco-friendly low-alkali two-part grout composition, wherein the aluminate-based hydration accelerator is an alkali metal aluminate and is potassium aluminate, sodium aluminate, or lithium aluminate, or the organic acid-based setting retardant is tartaric acid. It is an eco-friendly, low-alkali two-component grout composition characterized by citric acid or gluconic acid.

Through the present invention, alkali leaching can be effectively suppressed while securing the strength of the consolidated body, which is the basic performance of the grout material, and thus groundwater and soil contamination that may be caused by the construction of the grout material can be prevented.

In addition, in the process of securing the performance of cement-excluding grout materials, the mixing of expensive admixtures can be minimized, thereby reducing material costs and facilitating the supply of raw materials.

Figure 1 shows the compressive strength of specimens to which the present invention is applied by age.
Figure 2 shows the pH change of the specimen input tank to which the present invention is applied.

The detailed configuration of the present invention is described as follows.

The present invention is a two-component grout composition in which the first liquid, which is a quick-setting suspension, and the second liquid, which is an expandable suspension, are prepared respectively, and then the first liquid and the second liquid are injected into the ground and simultaneously merged and mixed to solidify. It is a grout material in which cement is completely excluded from both the first and second liquids, which are suspensions mixed with fine grains and water. When grout material is injected, the first liquid and the second liquid are mixed in equal amounts in principle. However, a slight change in the mixing ratio between the first and second liquids may be allowed depending on the injection site conditions, and the first liquid is mixed in a ratio of 40% to 60% by weight and the second liquid is 40% to 60% by weight. Can be joined and mixed.

In the present invention, the first liquid, which is a quick-setting suspension, is formed by mixing 20% to 30% by weight of the first powder to be described later and 70% to 80% by weight of water, and the second liquid, which is an expandable suspension, is the second liquid to be described later. It is formed by mixing 30% to 40% by weight of powder and 60% to 70% by weight of water, the mixing ratio of the first powder and water constituting the first liquid and the mixing ratio of the second powder and water constituting the second liquid can be adjusted to adjust the viscosity and fluidity of the liquid grout material required according to the characteristics of the ground under construction or the planned penetration range.

As described above, the present invention is a grout material in which cement is completely excluded from the powdery materials constituting the first liquid, which is a quick-setting suspension, and the second liquid, which is an expandable suspension, and the first powder, which is the powdery material constituting the first liquid, 30% to 45% by weight of silver calcium aluminate, 8% to 20% by weight of calcium ferroaluminate, 40% to 50% by weight of anhydrous gypsum, 1% to 5% by weight of aluminate-based hydration accelerator, and organic acid-based It is formed by mixing 0.1% by weight to 1% by weight of the setting retardant.

In addition, the powder material constituting the second liquid is also a composition completely excluding cement, and the second powder contains 35% to 55% by weight of blast furnace slag fine powder, 25% to 45% by weight of circulating fluidized bed fly ash, and potassium hydroxide 5%. It is formed by mixing % to 10% by weight, 5% to 10% by weight of anhydrous gypsum, and 2% to 8% by weight of cement kiln dust, and both the first powder and the second powder each have an area of 4,000㎠/ It is pulverized to a fineness of gram or more and then mixed using a dry mixing method.

In the first powder constituting the first liquid of the grout material of the present invention, the main powder components include calcium aluminate, calcium ferro aluminate, and anhydrous gypsum, of which calcium aluminate and Calcium ferroaluminate can effectively suppress initial and long-term leaching by forming a complete hydration-cured body when cured after injection of the grout composition of the present invention. This not only prevents groundwater contamination due to leaching, but also prevents groundwater contamination due to leaching. The durability and lifespan of the underground solidification body can be secured.

In particular, calcium aluminate has an excellent rapid setting effect, which can promote the hardening action and development of initial strength of the entire grout composition, and anhydrous gypsum plays a role in promoting the above-mentioned hydration reaction. It also plays a role in suppressing material separation within the suspension by fixing temporary excess water that is inevitably formed during the mixing process.

In addition, an aluminate-based hydration accelerator and an organic acid-based setting retardant are added to the first powder constituting the first liquid of the present invention. The aluminate-based hydration accelerator is an alkali metal aluminate such as potassium aluminate and sodium aluminate. Alternatively, lithium aluminate may be applied, and these aluminate-based hydration accelerators promote the hydration reaction in the process of mixing the first and second liquids when injecting the grout material of the present invention into the ground, and at the same time, increase strength and exhibit rapid setting effects. I do it.

Organic acid-based setting retardant, as its dictionary meaning, plays a role in slowing down the super-condensation of hydrates, and can extend the gel time of the grout material by increasing the dosage of the setting retardant, thereby extending the gel time of the grout material or ground conditions or Depending on the penetration range, the fluidity maintenance time of the liquid grout material can be adjusted, and tartaric acid, citric acid, or gluconic acid can be applied as such organic acid-based setting retarders.

In the second powder constituting the second liquid of the grout material of the present invention, the main powder components include blast furnace slag fine powder, circulating fluidized bed fly ash, potassium hydroxide, and anhydrous gypsum, of which blast furnace slag fine powder and circulating fluidized bed fly ash are industrially used. As a by-product, blast furnace slag fine powder is finely ground blast furnace slag that is rapidly cooled by spraying water on high-temperature molten slag generated as a by-product in the process of manufacturing pig iron in a blast furnace. It gives fluidity to the suspension and increases the strength of the solidified body. It shows the effect of preventing heat generation and salt damage, and circulating fluidized bed fly ash is also a type of fly ash, a by-product generated from coal-fired boilers such as thermal power plants, and has the effect of accelerating the setting speed and increasing fluidity.

Potassium hydroxide increases the strength and durability of grout materials by performing a pozzolanic reaction with silicon dioxide contained in large quantities in blast furnace slag fine powder and circulating fluidized bed fly ash, and anhydrous gypsum is a material that promotes hydration reaction and fixes excess water as described above. Performs a separation suppression function.

In addition, cement kiln dust is added to the second powder constituting the second liquid of the present invention, which is also an industrial by-product and is collected by collecting flying dust during cement manufacturing, and is the main component of cement kiln dust. The ingredient is calcium oxide (CaO), which performs the function of compensating for the shortcomings of the above-described circulating fluidized bed fly ash, and at the same time contains a large amount of compounds of the same type as the fine powder of the present invention, such as silicon dioxide and aluminum oxide, so that there is no unnecessary side reaction. Stable mixing is possible.

In the present invention, circulating fluidized bed fly ash is applied, which has a much higher calcium oxide (CaO) content than general fly ash, but has a somewhat lower calcium oxide content compared to supercritical fluidized bed fly ash. It is determined by type. Supercritical fluidized bed fly ash has a high calcium oxide content, but it is discharged from supercritical fluidized bed boilers, which are relatively poorly distributed, so it is not easy to supply and is expensive to procure, whereas circulating fluidized bed fly ash is Although the content of calcium oxide is somewhat insufficient, considering that many of the currently distributed coal-fired power generation boilers are circulating fluidized bed boilers, it has the advantage of easy supply and low procurement costs.

That is, the circulating fluidized bed fly ash applied in the present invention has a calcium oxide content of 15% to 20%, which is superior to general fly ash with a calcium oxide content of about 3%, and a calcium oxide content of 24%. It can be said that the calcium oxide content of circulating fluidized bed fly ash is somewhat insufficient compared to supercritical fluidized bed fly ash, which is about %, but nevertheless, the convenience of supply and demand and cost advantages can offset the disadvantages due to the lack of calcium oxide content. will be.

In particular, in the present invention, the above-mentioned disadvantages can be completely overcome by adding cement kiln dust containing a large amount of calcium oxide. The calcium oxide content in conventional cement kiln dust is 40% to 50%, which is added to the second powder. By adding it, it is possible to obtain benefits that exceed the effect of applying supercritical fluidized bed fly ash while applying circulating fluidized bed fly ash.

Hereinafter, the detailed configuration and operational effects of the present invention will be described through specific examples.

Mixing of the first powder for the preparation of the first liquid, which is a quick-setting suspension

Formulation of the first powder

A molding agent made by mixing 35% by weight of calcium aluminate, 15% by weight of calcium ferroaluminate, 46.7% by weight of anhydrous gypsum, 3% by weight of potassium aluminate as an aluminate-based hydration accelerator, and 0.3% by weight of tartaric acid as an organic acid-based setting retardant. 1 powder was formed.

Formulation of Type B first powder

Type B is prepared by mixing 40% by weight of calcium aluminate, 10% by weight of calcium ferroaluminate, 46.7% by weight of anhydrous gypsum, 3% by weight of potassium aluminate as an aluminate-based hydration accelerator, and 0.3% by weight of tartaric acid as an organic acid-based setting retardant. 1 powder was formed.

Formulation of second powder for preparation of second liquid, which is an expandable suspension

Combination of second form powder

50% by weight of blast furnace slag fine powder, 30% by weight of circulating fluidized bed fly ash, 8% by weight of potassium hydroxide, 7% by weight of anhydrous gypsum, and 5% by weight of cement kiln dust were mixed to form a second formable powder.

Formulation of Type B 2nd powder

Type B second powder was formed by mixing 40% by weight of blast furnace slag fine powder, 40% by weight of circulating fluidized bed fly ash, 8% by weight of potassium hydroxide, 7% by weight of anhydrous gypsum, and 5% by weight of cement kiln dust.

180 kg of the above-mentioned first form powder and 500 kg of water were homogeneously mixed to form a first liquid, which is a quick-setting suspension, and 250 kg of the above-mentioned second form powder and 430 kg of water were homogeneously mixed to form a second solution, which is an expanded suspension.

180 kg of the above-described first type powder and 500 kg of water were homogeneously mixed to form a first liquid, which is a quick-setting suspension, and 250 kg of the above-mentioned second type naked powder and 430 kg of water were homogeneously mixed to form a second liquid, which is an expanded suspension.

180 kg of the above-described bare first powder and 500 kg of water were homogeneously mixed to form a first liquid, which is a quick-setting suspension, and 250 kg of the above-mentioned second form powder and 430 kg of water were homogeneously mixed to form a second liquid, which is an expanded suspension.

180 kg of the above-described bare first powder and 500 kg of water were homogeneously mixed to form a first liquid, which is a quick-setting suspension, and 250 kg of the above-described bare second powder and 430 kg of water were homogeneously mixed to form a second liquid, which is an expanded suspension.

Comparative example

As a comparative example to Examples 1 to 4, 200 kg of sodium silicate and 480 kg of water were homogeneously mixed to form a first liquid, and 250 kg of ordinary Portland cement and 430 kg of water were homogeneously mixed to form a second liquid.

The components of Examples 1 to 4 and Comparative Examples described above are summarized in a table as follows.

Ingredients Table of Examples and Comparative Examples division Example 1 Example 2 Example 3 Example 4 Comparative example my
One
liquid Calcium Aluminate 35% 180kg 35% 180kg 40% 180kg 40% 180kg - Calcium ferroaluminate 15% 15% 10% 10% - Anhydrite 46.7% 46.7% 46.7% 46.7% - Potassium aluminate 3% 3% 3% 3% - tartaric acid 0.3% 0.3% 0.3% 0.3% - Silicate soda - - - - 200 kg water 500 kg 500 kg 500 kg 500 kg 480 kg my
2
liquid Blast furnace slag fine powder 50% 250kg 40% 250 kg 50% 250 kg 40% 250 kg - Circulating fluid bed fly ash 30% 40% 30% 40% - potassium hydroxide 8% 8% 8% 8% - Anhydrite 7% 7% 7% 7% - Cement kiln dust 5% 5% 5% 5% - Ordinary Portland Cement - - - - 250kg water 430kg 430kg 430 kg 430kg 430kg

In order to confirm the basic performance of the grout materials of Examples 1 to 4 and Comparative Examples described above, gel time measurements and homo-gel compressive strength tests were conducted.

Gel time, which is the time required for the liquid injection material to gel, is not only used as a key factor in estimating the initial loss amount of the injection material and controlling the penetration area, but also determines the properties such as leaching property, strength, and corrosion resistance during or after curing. It is a factor that determines the physical properties and durability of post-injection material, and is considered an important factor not only in responding to groundwater flow or salt water effects, but also in determining the re-construction cycle.

Indicators of the physical strength of grout materials include homogel strength, which measures the strength of the grout material itself by hardening it as a single material, and sand gel strength, which measures the strength of the grout material mixed with earth particles such as sand. The invention focuses not only on reinforcing or increasing bearing capacity for specific soils but also on suppressing leaching, and it was confirmed that the strength of pure grout material was achieved by measuring the homogel compressive strength.

First, to measure the gel time, prepare a pair of containers, pour about 100 g of the first or second liquid into each container, and then pour the suspension in one container into the other container at the same time to mix and measure the time. Starting, the time measurement is continued while repeatedly moving the first and second liquid mixtures from one container to the other container. When the fluidity of the mixture is lost and immediate movement between containers is stopped, the time measurement is stopped, and the mixture is Measure the time elapsed for gelation.

Gel time measurements for the above-described Examples 1 to 4 and Comparative Examples were performed five times for each sample to calculate the average value, and the results are shown in Table 2 below.

Gel times of Examples 1 to 4 and Comparative Examples division Example 1 Example 2 Example 3 Example 4 Comparative example gel
get on
lim
(candle) Primary 12 26 31 38 44 Secondary 13 23 27 37 41 3rd 11 21 29 33 40 4th 15 25 30 35 39 5th 12 23 26 37 38 average 12.6 23.6 28.6 36.0 40.4

As can be seen through Table 2, Examples 1 to 4 all showed good gel times compared to the Comparative Example, confirming relatively rapid curing and the effect of suppressing alkali leaching through this.

Meanwhile, in order to measure homogel strength, in Examples 1 to 4 and Comparative Examples, the first liquid and the second liquid were mixed and gelled, and then a number of specimens were manufactured in the shape of a 5 cm high cube, which were Cured at 23°C, the compressive strength was measured at 3 days, 7 days, 14 days, and 28 days, and the results are shown in Table 3 below and Figure 1 attached.

Compressive strength by age of Examples 1 to 4 and Comparative Examples Jaeryeong Example 1 Example 2 Example 3 Example 4 Comparative example 3 days 2.1MPa 1.7MPa 1.5MPa 1.3MPa 0.7MPa 7 days 3.7MPa 2.7MPa 2.7MPa 2.3MPa 1.3MPa 14 days 4.5MPa 3.0MPa 2.9MPa 2.6MPa 1.7MPa 28th 4.8MPa 3.2MPa 3.0MPa 2.7MPa 2.3MPa

As can be confirmed through Table 3 and the attached Figure 1, all of Examples 1 to 4 were found to exhibit superior strength over the entire age of measurement within 28 days compared to the Comparative Example, especially in the case of the Comparative Example. While there was a relatively gradual and gradual increase in strength with increasing age, all of Examples 1 to 4 showed a rapid increase in strength in the early stages of curing, confirming that the structure of the consolidated body was densified at an early stage, thereby improving the bearing capacity, etc. It was confirmed that not only the mechanical advantage but also the leaching inhibition ability was excellent.

As such, in terms of gel time and homogel strength, all of the above-described Examples 1 to 4 showed good results, and from this, it can be judged that the effect of suppressing alkali leaching is also excellent. However, accurate confirmation of the effect of suppressing leaching is not possible. To this end, the pH change in the specimen tank was measured.

As a specimen used to measure pH change, the above-mentioned 5cm high cubic specimen was used. After curing for 24 hours, it was demolded, two specimens were placed in a water tank containing 10 liters of purified water, and the change in pH over time was measured.

Measurement of pH was conducted from 1 hour to 72 hours after adding two specimens to 10 liters of purified water, and the results are shown in Table 4 below and Figure 2 attached.

Examples 1 to 4 and Comparative Example pH change in the specimen input tank division 1 hours 2 hours 4 hours 8 hours 24 hours 48 hours 72 hours Example 1 8.78 8.97 9.22 9.42 9.51 9.53 9.52 Example 2 8.97 9.11 9.37 9.53 9.72 9.71 9.73 Example 3 9.07 9.23 9.42 9.49 9.73 9.77 9.75 Example 4 9.17 9.31 9.47 9.51 9.69 9.78 9.77 Comparative example 9.77 9.98 10.27 10.49 10.71 10.87 10.97

As can be seen through Table 4 and the attached Figure 2, Examples 1 to 4 all exhibit slightly alkaline properties compared to the comparative examples not only at the initial stage of introduction of the specimen but also over time, thereby suppressing alkali elution. It was confirmed that this was advantageous, and in particular, in both Examples 1 to 4, it was confirmed that not only did the rate of increase in alkalinity slow significantly over time, but the increase in alkalinity stopped or was extremely minimal after several days or more.

Claims (1)

The first liquid, which is a quick-setting suspension, and the second liquid, which is an expandable suspension, are each prepared and injected into the ground, and at the same time, they merge in a ratio of 40% to 60% by weight of the first liquid and 40% to 60% by weight of the second liquid. A two-component grout composition to be mixed, wherein the first liquid is formed by mixing 20% to 30% by weight of the first powder and 70% to 80% by weight of water, wherein the first powder contains 30% to 45% by weight of calcium aluminate. Weight %, calcium ferroaluminate 8% to 20% by weight, anhydrous gypsum 40% to 50% by weight, aluminate-based hydration accelerator 1% to 5% by weight, and organic acid-based setting retardant 0.1% to 1% by weight. % is formed by mixing, and the second liquid is formed by mixing 30% to 40% by weight of the second powder and 60% to 70% by weight of water, and the second powder is 35% to 55% by weight of the blast furnace slag fine powder. %, 25% to 45% by weight of circulating fluidized bed fly ash, 5% to 10% by weight of potassium hydroxide, 5% to 10% by weight of anhydrous gypsum, and 2% to 8% by weight of cement kiln dust. In the low-alkali two-component grout composition,
An eco-friendly, low-alkaline two-component grout composition, wherein the organic acid-based setting retardant is tartaric acid, citric acid, or gluconic acid.

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