KR101096641B1 - Method for stabilizing ground - Google Patents

Abstract

PURPOSE: A method of stabilizing ground is provided to achieve good ground hardening performance, even if there is an organic material disturbing hardening in soil. CONSTITUTION: A method of stabilizing ground is as follows. Ground is organized to form road. Inorganic hardener is sprayed and mixed to the filed soil of the organized ground. The solution of ground hardening composition is sprayed to the mixed soil. After tramping, the mixed soil on the tramped ground is cured to form ground hardener. The ground hardening composition comprises bicarbonate of 10~20weight%, chloride or lignin sulfonate of 40~60weight%, sulfite of 10~20weight%, calcium stearate of 3~10weight%, and amine salt of 0~5weight%.

Description

Method for Stabilizing Ground

The present invention relates to a ground stabilization method, and more particularly, to a ground stabilization method that achieves excellent ground hardening performance despite the presence of organic substances contained in the soil to interfere with curing.

In general, soil cement is used to improve and compact the road ground (beds and roads). Soil cement is a stable process by mixing cement in roadbed or roadbed soil. However, when only cement is used as a curing agent, curing is difficult and the curing period is not only long, but the humic acid in the soil inhibits the integrity of cement. Therefore, the solidification strength is greatly reduced, especially in organic soil, clay soil, and silt soil. Because of this fall, crack shrinkage occurs even if more than twice the amount used for sand or gravel, and thus it is impossible to realize a predetermined high-strength strength, and hardening and gap filling of soil particles by cement hydration process. If the improvement is made by viscous soil, it is difficult to mix the soil and the modifier, and furthermore, when the soil contains a large amount of organic matter, there is a problem that the improvement effect is significantly lowered.

On the other hand, in addition to the simple cement method, there are two-liquid methods (methods containing a sensitizer and a dispersant as the main constituent material) mainly composed of silicate, and one-liquid method in which the hardener powder is dissolved in water and supplied. The silicate-based two-component method not only has a risk of causing alkaline pollution but also causes a decrease in strength after a long time, which is not suitable for long-term measures, and the one-liquid method has a problem of insufficient strength expression.

The present inventors have devised the present invention to solve the above problems of the prior art. Accordingly, it is an object of the present invention to provide a ground stabilization method that achieves excellent ground hardening performance despite the presence of organic materials contained in the soil that interfere with curing.

It is also an object of the present invention to replace some of the cement as part of industrial waste resource recycling technologies such as fly ash, blast furnace slag and silica fume, which contributes to the recycling of resources and is also collected at the site of the ground to be improved. It is to provide a way to stabilize the soil that allows the use of a soil.

In order to achieve the above object, the ground stabilization method of the present invention comprises the steps of forming a ground to form a road; Spraying and mixing an inorganic hardener on the ground soil of the ground; Sprinkling an aqueous solution of the ground hardening composition on the mixed soil in which the inorganic hardener and the spot soil are mixed; And pulverizing and curing the mixed soil of the ground to be chopped, thereby obtaining a ground hardened body. Here, the ground curing composition is 10 to 20% by weight bicarbonate, 40 to 60% by weight chloride or lignin sulfonate, 10 to 20% by weight sulfite, 3 to 10% by weight calcium stearate, and 0 to 5% by weight amine salt It includes.

In the above, it is preferable that the bicarbonate is calcium bicarbonate, the sulfite is calcium sulfite, and the ground hardening composition further includes at least one component selected from the group consisting of NaOH, citric acid and phosphate.

In addition, in the ground hardened body, the inorganic hardener is 15 to 30% by weight with respect to the soil, and the ground hardening composition is preferably 0.05 to 0.3% by weight with respect to the inorganic hardener. The inorganic curing agent is preferably cement or a mixture of 5 to 70% by weight of pozzolanic reactive material selected from the group consisting of 30 to 95% by weight cement, fly ash, blast furnace slag and silica fume.

The present invention not only exhibits excellent strength and hardening performance by the production of gypsum by chemical reaction of calcium sulfite, but also neutralizes the surface charge due to the Brownian movement of soil particles by the combination of inorganic salts and organometallic salts. It overcomes the interference of hardening of organic substances in the soil and promotes hydration reaction of cement and pozzolanic reaction such as fly ash, so that it shows excellent ground hardening performance. In addition, the present invention contributes to the recycling of resources and improves by using a special ground hardening composition to replace part of the cement as part of industrial waste recycling technology such as fly ash, blast furnace slag and silica fume. The use of soil collected at the site of the plowed ground can reduce the costs of collecting and transporting aggregates and promote the efficient use of resources. The ground improvement layer formed by the present invention has a low initial strength but a very long term strength, and the strength is improved as the time is prolonged, thereby increasing the durability of the road ground.

Hereinafter, the present invention will be described in more detail.

Ground stabilization method of the present invention comprises the steps of forming a ground to form a road; Spraying and mixing an inorganic hardener on the ground soil of the ground; Sprinkling an aqueous solution of the ground hardening composition on the mixed soil in which the inorganic hardener and the spot soil are mixed; And pulverizing and curing the mixed soil of the ground to be chopped, thereby obtaining a ground hardened body. Here, the ground curing composition is 10 to 20% by weight bicarbonate, 40 to 60% by weight chloride or lignin sulfonate, 10 to 20% by weight sulfite, 3 to 10% by weight calcium stearate, and 0 to 5% by weight amine salt It includes.

In the above, the bicarbonate is preferably calcium bicarbonate, and the sulfite is preferably calcium sulfite. The lignin sulfonate includes sodium salts, calcium salts, magnesium salts, and the like, and may be particularly formed by the reaction of lignin sulfonic acid with chlorides such as sodium chloride, calcium chloride, and magnesium chloride, which dissolve igneous rock silicon.

In the ground hardening composition of the present invention, calcium sulfite produces gypsum by a chemical reaction, thereby exhibiting strong strength and hardening performance.

In the process of hardening the soil to high strength by cement, when the organic material is contained in the soil, calcium ions and the like are adsorbed on the organic material, so the cement has a hardening ability against the soil. In order to compensate for this decrease in the hardenability of the cement, the present invention overcomes the interference of hardening of organic substances contained in the soil by neutralizing the surface charge due to the Brownian movement of the soil particles by a combination of suitable inorganic salts and organometallic salts. It promotes the hydration reaction of cement by inorganic ion and cation exchange property, and shows excellent ground hardening performance. At this time, a kind of crosslinking reaction is also progressed by the organometallic salt. Therefore, the ground hardening composition used in the present invention, when mixed with cement and used as a ground hardener, makes it possible to chemically form a balance by chemical ion exchange of soil collected at the site of the ground to be improved. Therefore, the present invention can save the overall process and time costs required for the collection and transportation of aggregates by using the soil collected on the site that requires the ground stabilization, and also facilitate the efficient use of industrial resources.

In addition, when a part of the cement is replaced with a pozzolanic reactive material such as fly ash, blast furnace slag and silica fume, the ground curing composition of the present invention also promotes pozzolanic reactions such as fly ash, thereby exhibiting excellent ground hardening performance. . Thus, the present invention contributes to the recycling of resources by allowing a portion of the cement to be replaced as part of industrial waste resource recycling techniques such as fly ash, blast furnace slag and silica fume when mixed with cement. As a result, the ground hardening composition used in the present invention exhibits excellent ground hardening performance in spite of the presence of organic substances contained in the soil that prevent hardening.

The ground hardening composition used in the present invention may further include at least one component selected from the group consisting of NaOH, citric acid and phosphate, which dissolve igneous rock silicon. These components provide dispersing performance or reinforce hardening performance with high strength. Such components may be used in amounts of up to 5% by weight of the total composition.

The present invention forms a ground hardened body by mixing in situ soil where the ground stabilization is necessary for road formation with an inorganic hardener and spraying the ground hardening composition on such mixed soil. The ground hardened body formed according to the present invention comprises soil, 15 to 30% by weight of an inorganic hardener for the soil, and 0.05 to 0.3% by weight of the ground hardening composition for the inorganic hardener. In the above, the inorganic curing agent may be cement, and may also be a mixture of 30 to 95 wt% cement, 5 to 70 wt% of pozzolanic reactive material selected from the group consisting of fly ash, blast furnace slag and silica fume. . If the composition for ground hardening is 0.05 wt% or more, preferably 0.1 wt% or more with respect to the weight of the inorganic curing agent, the purpose of the present invention can be achieved, and even if the amount is large, it does not significantly affect the achievement of the purpose. . However, if you use too much, it is not desirable to increase the cost without much performance improvement. More specifically, when 0.1 to 0.15% by weight is appropriate, and 0.2% by weight or more or 0.3% by weight or more, it is not preferable because only the cost increases regardless of the performance improvement.

The ground stabilizing method of the present invention for forming the above-mentioned ground hardened body first performs the step of laying the ground to form a road. The ground soil thus constructed is sprayed with inorganic hardener and the soil is re-mixed after the inorganic hardener is sprayed. Thereafter, the aqueous solution of the ground hardening composition is sprinkled on the mixed soil in which the inorganic hardener and the earth soil are mixed, and the ground soil is then aged and cured to obtain a ground hardened body. In the field of road construction, in order to improve the work efficiency, the above-mentioned work processes, namely, the ground is ground, the inorganic soil is sprayed on the ground soil of the ground, and then mixed and mixed again, and the mixed aqueous solution of the ground hardening composition is mixed on the mixed soil. This can be done using a device called a stabilizer to perform a batch of watering processes. Therefore, the present invention can stabilize the ground in a very simple way and can also reduce the work process, time and cost due to the collection of aggregates (sand) due to the use of on-site soil as it is required to transport the raw materials to the site Logistics costs can be reduced.

The amount of inorganic hardener for the soil depends on the type of soil such as sand, sandy soil, clay, alluvial soil, clay soil, volcanic soil, etc., the use of surface layers such as simple pavement, asphalt pavement, and the type of soil such as soft ground, plain ground, and good ground. According to the site combination design can be appropriately selected, for example, with respect to the soil weight of 1000 kg, about 100 ~ 300 kg can be mixed, usually 150 ~ 250 kg is enough. In cement mortar, which is formed by mixing general sand and cement, cement has sufficient strength as a building material when 35 to 45% by weight is mixed. The present invention uses sand while forming a hardened body using organic soil. Compared to cement mortar, the inorganic curing agent may be mixed with 15 to 20% by weight. This technical feature is obtained by using the ground hardening composition of the present invention.

The present invention also contributes to the recycling of industrial resources by enabling the replacement of some of the cement as part of industrial waste resource recycling technologies such as fly ash, blast furnace slag and silica fume by using special ground hardening compositions. .

Fly ash used in the ground hardened body of the present invention is a kind of coal ash (ash) generated as a by-product after coal pulverized coal is burned in a thermal power plant. Coal ash generated as by-product after coal pulverized coal is burned in thermal power plant is classified into fly ash, bottom ash, cinder ash and cenosphere, About 70-80% of these are fly ashes.

Among them, fly ash has already defined fly ash together with natural pozzolanic as concrete admixture for a long time, and is prescribed in KS standard in Korea. Fly ash produces an artificial pozzolanic reaction, which is almost hydrophobic, but reacts slowly with calcium hydroxide, a hydration product of lime and cement at room temperature, to produce insoluble calcium silicate and calcium aluminate hydrate, which is cured by Brownian movement. Its shape is circular. In the process of forming the ground cured body of the present invention, the fly ash improves the fluidity and heat of hydration of the mixture. Therefore, in the case of using fly ash, it is possible to obtain economic advantages due to the utilization of waste resource circulation and resource saving, and also to obtain the following advantages. That is, 1) In the present invention, when the inorganic curing agent containing fly ash is mixed with the soil and cured, the initial strength is small but the long-term strength is improved. 2) The temperature of the entire pavement decreases due to the heat of hydration, and 3) the watertightness is improved. 4) Resistance to volume change and freeze-thawing due to drying and wetting is more improved. 5) It is effective in suppressing alkali silica reaction.

On the other hand, there are also disadvantages as follows. That is, 1) the amount of unburned carbon is present, 2) organic admixture can be adsorbed on the surface of the particles, 3) there is the effect of fine particles with a particle size of 1 ㎛ or less, and quality fluctuation occurs depending on the time of manufacturing plant. . However, the interference of strength increase resulting from this problem can be solved by the above-mentioned ground hardening composition used in the present invention.

In the ground stabilization method of the present invention, the thickness of the ground improvement layer formed by the mixed soil is used for roads such as local roads, national roads, expressways, etc., surface and roadbed layers such as simple pavement, asphalt pavement, sand, sandy soil, clay, etc. Depending on the type of soil, such as alluvial soil, cohesive soil, volcanic soil, and the type of soil such as soft ground, normal ground, and good ground, it may be appropriately selected in the range of about 10 cm to 1 m.

In the present invention, the process of stabilizing the ground of the road is based on the inspection data after first inspecting the soil quality of the site, and also depending on whether the road paving is simple paving or asphalt paving and whether the ground is soft ground, normal ground or good ground. The mix design for the mixed soil should be carried out accordingly. This scheme is composed of points, fly ash, blast furnace slag, and silica fume to determine the weight ratio of pozzolanic reactive materials for cement in details, an inorganic hardening agent to determine the weight of an inorganic hardening agent for the soil weight of 1000 kg, or 1 m ³ Among the reactive materials, pozzolanic includes matters for determining each component and component ratio, matters for determining the weight ratio of the ground curing composition to the inorganic curing agent, matters for determining the component ratio of each component in the ground curing composition.

When such a compounding design is completed, a hardened body is formed according to the method described above, and it is used as a ground improving layer. Then, if necessary, a surface layer is formed of asphalt or concrete to complete the pavement.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only examples of the present invention and should not be understood as limiting the scope of the present invention.

1) Production Example

In order to prepare a ground hardening composition, 15 kg of calcium bicarbonate, 50 kg of lignin sulfonate, 15 kg of calcium sulfite, 5 kg of calcium stearate, 1 kg of NaOH, 1 kg of sodium citrate, and 1 kg of phosphate in the amount of water described in the following experimental example It was dissolved in to make an aqueous solution and used in the examples below.

2) Example

First, the inorganic hardener and the soil were mixed well with the composition for ground hardening of the example prepared above by the test compounding amount, placed in a specimen mold, and then chopped and cured to obtain a ground hardened body. Fly ash was used as the pozzolanic reactive material included in the inorganic curing agent.

Experimental Example 1

200 kg of cement, 1190 kg of Masato (water content of 8-9%), 0.2 kg of ground hardening composition (weight except water, the same below), 0.666 kg of water reducing agent (EMS), 0.154 kg of AE agent (519H), 242 L of water Two specimens of 2400 mx 800 mx 150 m were prepared by mixing. The specimen was measured for 7-day compressive strength by the test method of KS F 2405 (2005) and found to be 4.88 MPa.

Experimental Example 2

280 kg of cement, 1122 kg of Masato (water content of 8-9%), 0.2 kg of ground hardening composition, 0.666 kg of water reducing agent (EMS), 0.154 kg of AE agent (519H), and 242 L of water were mixed to produce 2400 mx 800 mx 100 m. Two specimens were produced. The specimen was tested for compressive strength for 7 days by the test method of KS F 2405 (2005) and found to be 8.70 MPa.

Experimental Example 3

1,280 kg of cement, 1122 kg of general soil (organic soil, water content of 8-9%), 0.2 kg of ground hardening composition, 0.666 kg of water reducing agent (EMS), 0.154 kg of AE agent (519H), 200 L of water, 1200 mx 800 Two specimens of mx 100 m were produced. The specimen was measured for 7-day compressive strength by the test method of KS F 2405 (2005) and found to be 6.68 MPa.

Experimental Example 4

280 kg of cement, 570 kg of Masato (water content of 8-9%), 570 kg of general soil (organic soil, water content of 8-9%), 0.2 kg of ground hardening composition, 0.666 kg of water reducing agent (EMS), AE agent (519H) 0.154 Two specimens of 1200 mx 800 mx 100 m were prepared by mixing kg and 200 L of water. The specimen was measured to have a compressive strength of 7 days by the test method of KS F 2405 (2005), and was confirmed to be 9.20 MPa. The 40 day compressive strength was also 10.27 MPa.

By the above experiments, it was confirmed that when the composition for ground hardening of the present invention was used, sufficient strength was obtained by mixing the organic soil and cement to form a ground hardened body. Therefore, the same experiment was repeated to check whether sufficient strength can be obtained even when a part of cement is replaced by fly ash.

Experimental Example 5

127 kg of cement, 23 kg of fly ash (15% of total inorganic hardener), 1000 kg of masato (water content of 8-9%), 0.15 kg of ground hardening composition, liquid reinforcing agent (with acrylic polymer dispersed in water, below) Same) 1.5 kg and a suitable amount of water was mixed to prepare a specimen. The specimens were tested for 14 days of compressive strength by 7.8 MPa and 28 days of compressive strength by 9.3 MPa by KS F 2405 (2005).

<Experimental Example 6>

The specimen was prepared by mixing 112 kg of cement, 38 kg of fly ash (25% of the total inorganic hardener), 1000 kg of masato (water content of 8-9%), 0.15 kg of ground hardening composition, 1.5 kg of liquid reinforcing agent, and an appropriate amount of water. . The specimen was tested for 14 days of compressive strength by 7.1 MPa and 28 days of compressive strength by 8.9 MPa by KS F 2405 (2005).

By the above experiments, it was confirmed that when the composition for ground hardening of the present invention was used to replace a part of cement with fly ash in an inorganic hardener mixed with organic soil, sufficient strength could be obtained. The experiment was carried out to determine the extent to which the amount of fly ash to replace cement is possible.

Experimental Example 7

0.96 kg of cement (40% of the total inorganic curing agent), 1.44 kg of fly ash (60% of the total inorganic curing agent), 10 kg of organic soil (water content 12%, organic soil: sand = 7: 3), 0.004 kg of ground hardening composition , 0.46 kg of liquid reinforcing agent and an appropriate amount of water were mixed to prepare a specimen. The specimen was measured for compressive strength for 7 days by the test method of KS F 2405 (2005) and found to be 4.88 MPa.

<Experimental Example 8>

0.96 kg of cement (40% of the total inorganic hardener), 1.44 kg of fly ash (60% of the total inorganic hardener), 10 kg of sludge waste (11% water content), 0.004 kg of ground hardening composition, 0.46 kg of liquid reinforcing agent and appropriate amount of water To prepare a specimen by mixing. The specimen was measured for compressive strength for 7 days by the test method of KS F 2405 (2005) and found to be 6.52 MPa.

Experimental Example 9

0.96 kg of cement (40% of the total inorganic hardener), 1.44 kg of fly ash (60% of the total inorganic hardener), 10 kg of construction waste (11% water content, brick, crushed building wall), 0.004 kg of ground hardening composition, 0.46 kg of the liquid reinforcing agent and a suitable amount of water were mixed to prepare a specimen. The specimen was tested for compressive strength for 7 days by the test method of KS F 2405 (2005) and found to be 7.5 MPa.

Experimental Example 10

0.96 kg of cement (40% of the total inorganic hardener), 1.44 kg of fly ash (60% of the total inorganic hardener), ascon waste (12% water content, ascon waste: sand = 1: 1) 10 kg, 0.004 kg of ground hardening composition , 0.46 kg of liquid reinforcing agent and an appropriate amount of water were mixed to prepare a specimen. The specimen was measured for compressive strength at 7 days by the test method of KS F 2405 (2005) and found to be 6.82 MPa.

Experimental Example 11

3.6 kg of cement (40% of the total inorganic hardener), 5.4 kg of fly ash (60% of the total inorganic hardener), organic soil (12% water content, loess: sand = 1: 1) 36 kg, ground cured composition 10.8 g, 144 g (519H, 48 g of acrylic polymer solids) and an appropriate amount of water were mixed to prepare a specimen. The specimens were 2.89 MPa as measured by 7 day compressive strength by KS F 2405 (2005) test method and 3.82 MPa as measured by 60 days compressive strength. Initial strength was slightly lower than the standard value of 3 MPa, but long-term strength was sufficiently applicable.

Experimental Example 12

3.6 kg of cement (40% of the total inorganic hardener), 5.4 kg of fly ash (60% of the total inorganic hardener), organic soil (12% water content, loess: sand = 1: 1) 36 kg, ground cured composition 10.8 g, 144 g (48 g of MMA polymer solids) and a suitable amount of water were mixed to prepare a specimen. The specimens were measured to have a compressive strength of 3.13 MPa for 7 days by KS F 2405 (2005) and 4.43 MPa for 60 days of compressive strength. Initial strength was slightly higher than the standard value of 3 MPa, but long-term strength was clearly higher than the standard value.

Experimental Example 13

3.6 kg of cement (40% of the total inorganic hardener), 5.4 kg of fly ash (60% of the total inorganic hardener), organic soil (12% water content, loess: sand = 1: 1) 36 kg, ground cured composition 10.8 g, A specimen was prepared by mixing 144 g of a liquid enhancer (EMS) and an appropriate amount of water. The specimens were 2.27 MPa as measured by the 7-day compressive strength by the test method of KS F 2405 (2005) and 3.23 MPa when the 60-day compressive strength was measured. Initial strength was lower than baseline 3 MPa, but long-term intensity was higher than baseline.

By the above experiments, it was confirmed that when the composition for ground hardening of the present invention was used, the inorganic hardener mixed with the organic soil could be obtained with sufficient strength even when the fly ash was replaced with up to 60% of the cement. On the other hand, it was tested whether a cured product having sufficient strength could be obtained even when only fly ash was used as an inorganic curing agent instead of cement.

Experimental Example 14

A specimen was prepared by mixing 2 kg of fly ash, 10 kg of ocher (11% water content), 0.003 kg of ground hardening composition, 0.4 kg of liquid reinforcing agent, and an appropriate amount of water. The specimens were demolded but were all torn down and no strength test was possible.

Experimental Example 15

A specimen was prepared by mixing 2 kg of fly ash, 10 kg of masato (water content of 11%), 0.003 kg of ground hardening composition, 0.4 kg of liquid reinforcing agent, and an appropriate amount of water. The specimens were demolded but were all torn down and no strength test was possible.

By the above experiments, it was confirmed that even when the composition for ground hardening of the present invention was used, when only fly ash was used as the inorganic hardener, hardened bodies of organic soil could not be obtained.

Claims (5)

Laying ground to form a road; Spraying and mixing an inorganic hardener on the ground soil of the ground; Sprinkling an aqueous solution of the ground hardening composition on the mixed soil in which the inorganic hardener and the spot soil are mixed; Comprising a step of aging and curing the mixed soil of the ground after the chopped ground to obtain a ground hardened body,
The ground hardening composition comprises 10 to 20% by weight of bicarbonate, 40 to 60% by weight of chloride or lignin sulfonate, 10 to 20% by weight of sulfite, 3 to 10% by weight of calcium stearate, and 0 to 5% by weight of amine salt. Ground stabilization method characterized in that. The method of claim 1,
The bicarbonate is calcium bicarbonate, the sulfite is calcium sulfite, characterized in that the ground. The method according to claim 1 or 2,
The ground hardening composition further comprises at least one component selected from the group consisting of sodium hydroxide (NaOH), citric acid and phosphate. The method of claim 1,
In the ground hardened body, the inorganic hardener is 15 to 30% by weight based on the site soil, and the ground hardening composition is 0.5 to 3% by weight based on the inorganic hardener. The method of claim 4, wherein
Wherein said inorganic curing agent is cement or a mixture of 5 to 70 weight percent of pozzolanic reactive material selected from the group consisting of 30 to 95 weight percent cement, fly ash, blast furnace slag and silica fume.