KR20100099019A - Eco friendly, early strength, extensive grout additive and grout material and reinforcing earth anchor method using the grout material - Google Patents

Abstract

PURPOSE: An eco-friendly and early-strength expansive grout additive is provided to improve the mobility and workability of a group material, to obtain compressive strength, required for tensioning an anchor in 1-3 days, and to prevent group materials from being separated. CONSTITUTION: An eco-friendly and early-strength expansive grout additive comprises: 3-90 weight% of lime; 3-90 weight% of a curing accelerator which is selected from sodium sulfate, potassium sulfate, aluminum sulfate, nitrous acid calcium, iron sulfate, or their mixture; 0.1-3 weight% of a volume expanding agent; 3-20 weight% of one or more water-reducing agents which are selected from a naphthalene-based compound, a melamine-based compound, a polycarboxylic acid-based compound, or their mixture; and 3-30 weight% of iron sulfate.

Description

ECO FRIENDLY, EARLY STRENGTH, EXTENSIVE GROUT ADDITIVE AND GROUT MATERIAL AND REINFORCING EARTH ANCHOR METHOD USING THE GROUT MATERIAL}

The present invention relates to a grout mixture material, a grout material, and a ground reinforced anchor method using the ground reinforced anchor method. In more detail, a grout mixture is formed of a composition comprising a slaking lime, a curing accelerator such as sodium sulfate, a volume expanding agent, a powder high-performance reducing agent, and ferrous sulfate, and the mixture is mixed with cement and water at a predetermined ratio. It relates to a ground reinforcement anchor technology for generating and injecting grout material for ground anchors.

In general, the ground reinforcement anchoring method is an effective method for applying a lateral or vertical restraining force or a preceding load to a structure by connecting high-strength steel to fix the structure of civil engineering or construction on the ground and introducing high tension to the steel. Recently it is actively used at home and abroad. Anchor, as it is meant, means nailing to the ground, which has the effect of tying the ground and the structure into one aggregate and is generally composed of steel wire and cement grout. Ground reinforcement anchor method is widely used for supporting earthwork of temporary earth wall, permanent anchor earth wall, transmission tower foundation, dam reinforcement, buoyancy anchor of underground structure, slope reinforcement. Hereinafter, exemplary representative earth anchor structures will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of a general earth anchor structure installed for ground reinforcement.

Ground reinforcement anchoring method is to drill a hole in the ground and insert reinforcing steel or PC steel wire, grout and harden milk mixed with cement and water, and then apply tension force to PC steel wire or steel reinforcement from outside. At this time, the problem in the anchor is a general cement milk, the water / cement ratio is high in order to improve the fluidity, which causes the material separation in the perforated holes resulting in bleeding water. If the bleeding number generated in the upper portion of the perforated hole is lost later, the portion remains as a void, and there is a problem in that the void cannot increase the peripheral friction when rebar tensioning.

Therefore, expansion is required to completely fill the voids, and a method of grouting by adding a small amount of a substance such as a volume expanding agent is used to prevent such voids from occurring.

In addition, when the general cement milk is used as a grout material, since the water / cement ratio used is high, the strength required for tensile work appears after 7 days, there is a problem that the overall work process is long.

On the other hand, cement-based materials contain trace amounts of chromium, and as the throughput of industrial waste increases during cement manufacturing, the chromium content is increasing, so the hexavalent chromium content that may contaminate underground water quality tends to be increased. This is necessary.

An object of the present invention is a ground reinforcement anchor method that can shorten the air by expressing a certain amount of the grout material in the manufacturing of the grout material used in the anchor construction method for the ground reinforcement to shorten the strength and suppress the material separation and bleeding water generation It is to provide a grout mixture material, grout material and ground reinforcement anchoring method using the same.

In addition, the object of the present invention is to improve the fluidity and workability to facilitate the grouting operation, and after curing hardened hexavalent chromium to reduce the hexavalent chromium, ground grout material for ground reinforcement anchoring method does not occur To provide a grout material and ground reinforcement anchor method using the same.

Eco-friendly crude expandable grout mixture according to the present invention is 3 to 90% by weight of lime; 3 to 90% by weight of any one or more curing accelerators selected from the group consisting of sodium sulfate, potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate, iron sulfate and mixtures thereof; 0.1 to 3 weight percent volume expanding agent; 3 to 20% by weight of any one or more powder high performance reducing agents selected from the group consisting of naphthalene-based, melamine-based, polycarboxylic acid-based, and mixtures thereof.

In addition, the environment-friendly roughening type expandable grout mixture according to the present invention 3 to 30% by weight of ferrous sulfate; preferably further comprises.

Eco-friendly crude expandable grout material according to the present invention is cement; And 3 to 90 wt% of calcined lime, at least one hardening accelerator selected from the group consisting of sodium sulfate, potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate, iron sulfate, and mixtures thereof, And a grout mixture comprising 3 wt% to 3 wt% of naphthalene-based, melamine-based, polycarboxylic acid-based, and mixtures thereof, and 3-20 wt% of the powdered high-performance reducing agent. The grout mixture is characterized in that 0.5 to 10% by weight based on 100% by weight cement.

In addition, in the environmentally friendly steel-type expandable grout material according to the present invention, the grout mixture material is 3 to 30% by weight of ferrous sulfate; preferably further comprises.

Geotechnical reinforcement anchoring method using environmentally friendly steel type expandable grout material according to the present invention is selected from the group consisting of 3 ~ 90% by weight of hydrated lime, sodium sulfate and potassium sulfate, aluminum sulfate and calcium acetate, sodium carbonate and iron sulfate and mixtures thereof 3 to 90% by weight of one or more curing accelerators, 0.1 to 3% by weight of volume expanding agent, 3 to 20% by weight of any one or more powdered high performance reducing agents selected from the group consisting of naphthalene-based and melamine-based and polycarboxylic acid-based and mixtures thereof To form a grout mixture; Forming a hole in the ground; Inserting an anchor in the hole; Mixing 0.5 to 10% by weight of the grout mixture with respect to cement, water and cement, followed by stirring to produce a grout material in the form of a paste; And injecting a grout material into the hole.

In addition, the step of forming a grout mixture in the ground reinforcement anchoring method using an environment-friendly crude expansion-type expandable grout material according to the present invention, the addition of ferrous sulfate 3 to 30% by weight to the grout mixture to form a grout mixture; It is preferable to be configured.

According to the present invention, the flowability of the grout material is improved and the workability is improved, so that the injection is convenient and the long-distance transfer is possible, and the compressive strength required for the tensioning work of the ground reinforcement anchor can be expressed within 1 to 3 days. As it is excellent, it is possible to carry out the tensioning work of anchor body early so that the construction period can be greatly reduced.

In addition, according to the present invention is excellent in preventing the separation of the material of the grout material and can prevent volume shrinkage during curing by the expansion action, and by reducing the amount of hexavalent chromium harmful to the human body in the grout material after curing, eco-friendly ground reinforced anchor There is an effect that can be constructed.

The grout mixture according to the present invention is mixed with cement and water to form a grout material, which is well stirred and used in the form of paste into the hole into which the anchor is inserted by the ground reinforcement anchoring method.

In the grout mixture according to the present invention, calcined lime (calcium hydroxide: Ca (OH) ₂ ), sodium sulfate, and the like are used as a curing accelerator that enables the tensioning of the anchor body early.

The calcined lime used at this time is not particularly limited, but digested quicklime (calcium oxide: CaO) (preferably calcium hydroxide) is preferable. It is also possible to use calcined lime produced by extinguishing an expanded material containing calcined dolomite or free lime (F-CaO).

The powder degree of slaked lime used in the present invention preferably has a specific surface area of 3,000 cm 2 / g or more equal to or more than cement, and the higher the powder level, the better the hardening action.

In addition to hydrated lime, inorganic sulfates such as sodium sulfate, potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate, iron sulfate and the like are used as a curing accelerator used to express strength early in the present invention. In particular, sodium sulfate shows the best results among them, and when used at 5 wt% or less, the initial strength expression effect is small, and even when used at 20 wt% or more, the initial strength enhancing effect is no longer improved. It is preferably set to 30% by weight.

In addition, the volume expanding agent used in the present invention is used for the purpose of preventing shrinkage before curing of the grout material, and when mixed with the grout material, it is possible to expand the volume by generating gas by chemical reaction to form bubbles.

Representative volume expanding agents include metal aluminum powder, peroxide, hypochlorite, sodium bicarbonate, ammonium chloride and the like. However, it is most suitable to use metal aluminum powder in view of the nature of the generated gas, economics, and control of the reaction.

The metal aluminum powder reacts with an alkaline substance in cement to generate hydrogen gas to form bubbles, as shown in [Scheme 1] below.

Scheme 1

2Al + Ca (OH) ₂ + 2H ₂ O => CaAl ₂ O ₄ + 3H ₂ ↑

It is preferable that a volume expanding agent such as metal aluminum powder having the above reaction is contained in an amount of 0.1 to 1.0% by weight. This is because if the volume expanding agent is less than 0.1% by weight, the role of the expanding agent is insignificant, and if it exceeds 1.0% by weight, the phenomenon of swelling due to overexpansion may occur.

In addition, the powder high performance reducing agent used in the present invention is used to improve the fluidity of the grout material is preferably contained 5 to 20% by weight. The powder high performance reducing agent (powder fluidizing agent) may be selected from the group consisting of naphthalene-based, melamine-based, polycarboxylic acid-based, and mixtures thereof, and is preferably a naphthalene-based material having good initial strength expression and low cost.

In addition, ferrous sulfate (FeSO ₄ ) may be further added to the grout mixture according to the present invention to reduce water-soluble hexavalent chromium contained in cement.

That is, the water-soluble hexavalent chromium remaining in the cement in the grout material may cause environmental pollution such as contaminating drinking water as a contaminant, and by reducing the hexavalent chromium by adding ferrous sulfate to the grout mixture according to the present invention. Can be.

The principle of reducing water-soluble hexavalent chromium by ferrous sulfate is as follows.

The water-soluble hexavalent chromium by the cement in the grout material is present as CrO ₄ ^2- or Cr ₂ O ₇ ^2- ions. Therefore, when a reducing agent such as ferrous sulfate is added, it is converted into trivalent chromium and combined with OH- ions in the aqueous solution to precipitate as Cr (OH) ₃ .

At this time, when the ferrous sulfate is added in less than 5.0% by weight, the effect of reducing hexavalent chromium in the grout material is less, and when added at 30.0% by weight or more, the effect of reducing hexavalent chromium is no longer improved. Therefore, in order to effectively reduce the water-soluble hexavalent chromium in the grout material, it is preferable to further add 5.0% to 30.0% by weight of ferrous sulfate in the components of the grout mixture according to the present invention.

Hereinafter, with reference to the accompanying table will be described in detail the examples and experimental results of the grout mixture material, the grout material according to the present invention.

■ Example 1

Example 1 shows the characteristics (compressive strength, bleeding rate, etc.) of the grout material produced by mixing it with cement and water while varying the composition ratio of slaked lime and sodium sulfate contained in the grout mixture material according to the present invention, and the present invention is not applied. Experimental results compared with the characteristics of the grout material.

TABLE 1

Table 1 shows Experimental Examples 1 to 4 to which the grout mixture according to the present invention was applied and Comparative Example 1 showing general grout materials to which the grout mixture according to the present invention was not applied.

Experimental Examples 1 to 4 add 3.0% by weight of grout mixture according to the present invention with respect to 100% by weight of ordinary portland cement commercially available, and mix water to 42% with respect to 100% by weight of ordinary portland cement. To produce a ground anchor grout material.

At this time, the composition ratio of the slaked lime and sodium sulfate to 100% by weight of ordinary Portland cement were different from each other, and Experimental Example 1, Experimental Example 2, Experimental Example 3, and Experimental Example 4 were divided.

In addition, Comparative Example 1 shows the mixing of the general grout material, in order to adjust the fluidity of the grout material in the same manner as in Experimental Examples 1 to 4, the amount of water was blended so as to be 52% to 100% by weight of ordinary Portland cement.

TABLE 2

Table 2 shows the results of measuring the compressive strength according to the bleeding rate, the number of days for the experimental examples 1 to 4 and Comparative Example 1 shown in the above [Table 1].

The 'liquidity' values described in [Table 2] were measured using a dropping funnel specified in KS F 2432 (the consistency test method of injection mortar), which is a fluidity measuring instrument. The KS F 2432 has an inner diameter of 70 mm, Measure the time until all the measurement materials are discharged after putting the measurement material in a brass container with 10 mm inside diameter, 420 mm height, 10 mm inside diameter, and 30 mm length outflow pipe. It is intended to measure the fluidity of the material.

For example, referring to Experiment 3 of Table 2, 100% by weight of cement, 3% by weight of grout mixture (calcined lime 30.0%, sodium sulfate 60.0% by weight, 0.1% by volume expander, 9.9% by weight high-performance reducing agent), 42% by weight of water Immediately after the preparation of the grout material produced by mixing the%, it took 8.0 seconds to completely fill the discharge funnel container and discharge it, and 13.9 seconds after 30 minutes after manufacture. As the time passes, the flowability of the grout material is lowered because a reaction occurs between the cement and the curing accelerator.

The 'bleeding rate' described in [Table 2] is a result measured by the method specified in KS F 2433, and represents a value obtained by converting the height of the water accumulated at the top of the entire height of the grouting material after 3 hours of grouting as a percentage.

According to the test results, bleeding hardly occurs in the grout material (Experimental Example 1 to Experimental Example 4) using the mixed material according to the present invention, but in the case of the general grout material (Comparative Example 1) using only ordinary portland cement. It can be seen that a large amount of bleeding occurs.

In addition, the "compressive strength" described in [Table 2] is a measurement result by the method specified in KS F 2426, and the mold is filled with a grout material having a diameter of 5 cm and a height of 10 cm. This is the result of measuring the compressive strength of the grout material at 2, 3, 7 days of age.

According to the test results, it can be seen that the compressive strength expression of Experimental Examples 1 to 4 using the grout mixture according to the present invention is significantly higher than that of Comparative Example 1 using only ordinary Portland cement.

That is, Experimental Examples 1 to 4 using the grout mixture according to the present invention all express a compressive strength of 20 MPa or more, which can be tensioned at 2 days of age, but in Comparative Example 1 not using the mixture according to the present invention, Only 20 MPa or more of compressive strength capable of tensile work has been developed.

That is, when using the mixed material according to the present invention has an effect that can shorten the tensile work schedule of about 5 days compared to the case of using a grout material using only ordinary portland cement.

Example 2

Example 2 is an experimental result comparing the case of the normal grout material to which the compressive strength was measured by varying the content of mixing the grout mixture material according to the present invention into cement, and not to which the present invention was applied.

[Table 3]

Experimental Examples 5 to 8 in Table 3 above show the mixing ratio of calcined lime and sodium sulfate in a grout prepared by mixing 0.3 wt% of a high performance water reducing agent and 0.03 wt% of a volume expander with respect to 100 wt% of commercially available Portland cement. The hardening accelerator prepared at 80:20 was added to 1.0, 2.5, 5.0, and 10.0% by weight of the external halo based on the previously prepared grout material to prepare a ground anchor grout material. At this time, the water used was usually mixed to 42% with respect to 100% by weight of Portland cement.

In addition, Comparative Example 2 shows the blending of the general grout material to which the present invention is not applied, and the amount of water used was generally 52% to 100% by weight of Portland cement to have the same fluidity as in Experimental Examples 5 to 8.

[Table 4]

Table 4 shows the results of measuring the compressive strength according to the number of days of aging for Experimental Examples 5 to 8 and Comparative Example 2 shown in the above [Table 1].

According to the test results, it can be seen that the expression of compressive strength of Experimental Examples 5 to 8 according to the present invention is significantly higher than that of Comparative Example 2 without using the grout mixture according to the present invention.

That is, Experimental Examples 5 to 8 all express the compressive strength of 20 MPa or more, which can be tensioned at 2 days of age, and thus shorten the tensile work schedule of 5 days compared to Comparative Example 2 without using the mixed material according to the present invention. have.

In addition, in the case of using the grout mixture according to the present invention, as the amount of the curing accelerator mixed with slaked lime and sodium sulfate at 80:20 increases (Experimental Example 5: 1.0 wt%, Experimental Example 6: 2.5 wt%, Experimental Example 7: 5.0 wt%) It can be seen that the compressive strength expression tends to increase on the second day of age. However, when the amount of the curing accelerator is used in 10% by weight (Experimental Example 8), the results show that the strength is lowered.

Therefore, it can be seen that it is appropriate to use about 1 to 5% by weight of the curing accelerator composed of slaked lime and sodium sulfate, usually based on Portland cement.

Example 3

Example 3 is a result of measuring the change in the content of hexavalent chromium remaining in the grout as the ferrous sulfate is added to the grout mixture according to the present invention, compared with the case of not applying the present invention .

TABLE 5

In Table 5, Experimental Examples 9 to 11 show that 3.0 wt% was added to the outer shell after preparing a grout mixture by changing the blending ratio of ferrous sulfate to 100 wt% of commercially available ordinary Portland cement. At this time, the mixed materials contained in Experimental Examples 9 to 11 are differently blended so that the mixing ratio of ferrous sulfate occupies 10.0% by weight, 20.0% by weight, and 30.0% by weight of the mixed material, 0.1% by weight of the volume expander and 9.9% by weight of the high performance reducer. % Is combined and slaked lime and sodium sulfate are mixed 2: 1 to make up the remainder.

In addition, Comparative Example 3 corresponds to the grout mixture proposed in the present invention, but shows a case in which ferrous sulfate was not applied at all in order to compare with Experimental Examples 9 to 11 in which ferrous sulfate was added.

Pollutants, such as water-soluble hexavalent chromium, are generally managed under the Soil Environment Conservation Act of 31 March 2005. According to the Soil Environment Conservation Act, water-soluble hexavalent chromium is less than 4 ppm in forest, school land, rivers, parks, and vegetation areas where the general ground anchoring is carried out. It is stated that it should be managed below 12ppm of 'I' area.

According to the experimental results of [Table 5], in the case of Comparative Example 3 in which ferrous sulfate, a hexavalent chromium reducing agent, was not used in the mixture, 21 ppm of water-soluble hexavalent chromium was detected. It can be seen that the excess.

On the other hand, in Examples 9 to 11 in which ferrous sulfate was added, it was found that as the amount of ferrous sulfate added increased, the detection amount of water-soluble hexavalent chromium decreased. In the case of Experiment 11 to occupy it can be confirmed that the water-soluble hexavalent chromium is not actually detected.

Therefore, when it is used in the ground reinforcement earth anchor method, it is possible to construct an environment-friendly construction without elution of water-soluble hexavalent chromium.

Hereinafter, the ground reinforcement anchoring method according to an embodiment of the present invention will be described in detail with reference to the accompanying table and drawings.

2 is a flow chart showing the entire construction process of the ground reinforcement anchor method using the environment-friendly crude expansion-type expandable grout mixture according to an embodiment of the present invention.

Ground reinforcement anchor method using the environment-friendly roughening type expandable grout mixture according to the present invention is made through the following process.

As described above, 3 to 90% by weight of any one or more hardening accelerators selected from the group consisting of 3 to 90% by weight of hydrated lime, sodium sulfate and potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate, iron sulfate and mixtures thereof 0.1 to 3% by weight of the expanding agent, naphthalene-based and melamine-based and polycarboxylic acid-based and mixtures of any one or more powdered high performance reducing agent selected from the group consisting of a mixture thereof is mixed to form a grout mixture (S10).

In this case, it is effective when sodium sulfate is used as a curing accelerator other than slaked lime, and as a powder high performance reducing agent, it is preferable to use a nattalene-based material for initial strength expression and a low price.

In addition, in order to reduce the hexavalent chromium remaining in the cement, 3 to 30% by weight of ferrous sulfate may be further added to form a grout mixture.

After preparing the grout mixture material having the above combination configuration, the ground reinforcement anchor installation work is performed.

First, after forming a hole to the ground reinforcement anchor installation work (S20), the anchor is inserted into the hole (S30).

Then, cement and water are mixed with the previously prepared grout mixture to produce a ground anchor grout material (S40). At this time, the process of generating the grout material may be prepared in advance before the ground reinforcement anchor installation work proceeds, or may be prepared by mixing the cement, water, and grout mixed material immediately before injecting the grout material.

When producing the grout material, the grout mixture prepared above is added at a ratio of 0.5 to 10% by weight based on 100% by weight of cement. In this case, it is preferable to use portland cement. In addition, water is added by about 38 to 45% by weight relative to the cement.

In the above ratio, the cement, grout mixture and water are mixed well and mixed to stir to form a paste-type grout material.

Then, the grout material is injected into the hole into which the anchor is inserted by using a pump or the like (S50).

Thereafter, when the grout material is hardened to some extent and has a predetermined compressive strength or more, the tensile work is performed.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a view showing the configuration of a general earth anchor structure installed for ground reinforcement,

Figure 2 is a flow chart showing the entire construction process of the ground reinforcement anchor method using the environment-friendly roughening type expandable grout mixture according to an embodiment of the present invention.

Claims (6)

Slaked lime 3 to 90 wt%; 3 to 90% by weight of any one or more curing accelerators selected from the group consisting of sodium sulfate, potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate, iron sulfate and mixtures thereof; 0.1 to 3 weight percent volume expanding agent; 3 to 20% by weight of any one or more powder high performance reducing agents selected from the group consisting of naphthalene-based, melamine-based, polycarboxylic acid-based, and mixtures thereof; Grout mixture comprising a. The method according to claim 1, The grout mixture is 3 to 30% by weight of ferrous sulfate; The grout mixture further comprises. cement; And 3 to 90% by weight of slaked lime, 3 to 90% by weight of at least one curing accelerator selected from the group consisting of sodium sulfate, potassium sulfate, aluminum sulfate, calcium acetate, sodium carbonate and iron sulfate, and mixtures thereof, 3% by weight, grout mixture comprising 3 to 20% by weight of any one or more powder high performance reducing agent selected from the group consisting of naphthalene-based, melamine-based and polycarboxylic acid-based and mixtures thereof; And, The grout mixture is 0.5 to 10% by weight based on 100% by weight of the cement grout, characterized in that added. The method according to claim 3, The grout mixture is 3 to 30% by weight of ferrous sulfate; The grout material further comprises. 3 to 90% by weight of hydrated lime, 3 to 90% by weight of at least one curing accelerator selected from the group consisting of sodium sulfate and potassium sulfate, aluminum sulfate and calcium acetate, sodium carbonate and iron sulfate, and mixtures thereof, and 0.1 to 3% by volume expanding agent %, 3 to 20% by weight of any one or more powder high performance reducing agent selected from the group consisting of naphthalene-based and melamine-based and polycarboxylic acid-based and mixtures thereof to form a grout mixture; Forming a hole in the ground; Inserting an anchor in the hole; Mixing the cement, water, and the grout mixture of 0.5 to 10% by weight of the cement, followed by stirring to produce a grout material in the form of a paste; And Injecting the grout material into the hole; Ground reinforcement anchor construction, including. The method according to claim 5, The grout mixture forming step, Adding 3 to 30% by weight of ferrous sulfate to the grout mixture to form a grout mixture; Ground reinforcement anchor method is configured to include more.

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