KR101503841B1 - Environment-friendly geopolymer composition for stabilization of soft ground and strength enhancement and the method using thereof - Google Patents

Abstract

The present invention relates to an environmentally friendly geopolymer composition for the stabilization and strength enhancement of soft ground and a construction method using the same and, more specifically to an environmentally friendly geopolymer formed by mixing 30-70 wt% of blast furnace slag powder, 10-40 wt% of cement, 1-30 wt% of antishrinking agents, 1-10 wt% of quick setting blending materials and 0.1-5 wt% of alkali activators. The present invention enables an environmentally friendly construction preventing environmental pollution by manufacturing the geopolymer composition manufactured by minimizing cement consumption and using pozzolan materials such as blast furnace slag powders, facilitates pumpability by high fluidity, enables self-build using chute and is able to prevent volume contraction from being caused by absorbing surplus water after construction and being expanded.

Description

TECHNICAL FIELD [0001] The present invention relates to an environmentally friendly geopolymer composition for stabilizing and strengthening a soft soil, and a construction method using the same. [0002]

The present invention relates to an environmentally friendly geopolymer composition for stabilizing and strengthening a soft soil and a method of using the same. More particularly, the present invention relates to a geopolymer composition prepared by using a pozzolanic material such as blast furnace slag powder It is possible to make environment-friendly construction that does not cause environmental pollution, and it is possible to easily carry out pneumatic construction with a high fluidity, and also to be able to directly use a chute, to absorb surplus water after construction, and to cause volume shrinkage The present invention relates to an eco-friendly geopolymer composition for stabilizing a soft soil and enhancing strength, and a construction method using the same.

Generally, in soft ground improvement work, soft ground consolidation method which improves soft ground by mixing and solidifying a fire is added to surface and deep natural soils, and in this case, Portland cement Slag cement, or cement mortar mixed with pozzolanic materials is mainly used.

However, when the conventional cement mortar for soft ground improvement is improved by the surface layer mixing treatment method for the surface portion (within 1 to 2 m) of the ground, in the case of using portland cement alone, It is difficult to solidify the burnt reservoirs due to the organic matter contained in the soil, and there is a problem that cracks due to drying shrinkage occur when a large amount of the slag cement or the cement is added. In case of a fire produced by adding pozzolan substances to slag cement or cement Due to the nature of the pozzolanic reaction, the strength development is low and construction delays occur. Especially, it is difficult to apply to the construction in winter.

Korean Patent Registration No. 10-0516188 Korean Patent Registration No. 10-0471195

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for stabilizing and strengthening a soft soil which improves the mixing performance between an environmentally friendly geopolymer composition and soil, generates no environmental pollution after curing, And an object of the present invention is to provide a construction method using the same.

According to an aspect of the present invention,

A mixture of 30 to 70% by weight of blast furnace slag powder, 10 to 40% by weight of cement, 1 to 30% by weight of a shrinkage inhibitor, 1 to 10% by weight of a tackifying admixture and 0.1 to 5% by weight of an alkali activator.

Here, the environmentally friendly geopolymer composition is mixed with the gypsum and mixed water in an amount of 5 to 30% by weight based on 100% by weight of the gypsum.

Here, the environmentally friendly geopolymer composition is mixed with the gypsum and then mixed with water, wherein 100 to 500 wt% of the mixed water is mixed based on 100 wt% of the environmentally friendly geopolymer composition.

Here, the blast furnace slag powder is a blast furnace slag powder for KS F 2563 concrete.

Here, the above-mentioned cement is used either alone or mixed with one kind of portland cement or three kinds of crude steel cements.

Here, the shrinkage inhibitor may be any one or a mixture of two or more selected from the group consisting of alpha type hemihydrate gypsum, hypocotyl gypsum and anhydrous gypsum.

Here, the above-mentioned quick-setting admixture may be any one or a mixture of two or more selected from calcium aluminate powder, calcium sulphoaluminate powder and alumina cement.

Here, the alkaline activator is a sodium-based alkaline activator.

Herein, the alkali active agent is used by mixing any one or two or more selected from among sodium sulfate, sodium silicate and sodium hydroxide.

According to another aspect of the present invention,

In the method of applying the environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil, 5 to 30% by weight of the geopolymer composition is added to the mixer based on 100% by weight of the soil and the mixture, By weight based on 100% by weight of the environmentally friendly geopolymer composition; A transfer process for transferring the mixed mixed composition to the site; A laying process in which the transferred mixed composition is laid on the surface layer of the ground using a field chute; And a curing step of curing the mixed composition after completion of the laying.

Here, the transferring step is carried out by the mixer to the site using a pump and a press-feeding tube, or to a site by a remicon conveying truck.

According to the eco-friendly geopolymer composition for stabilizing and strengthening the soft soil of the present invention having the above-described structure, the geopolymer composition prepared using the pozzolanic material such as blast furnace slag powder It is possible to make environment-friendly construction that does not cause environmental pollution, and it is possible to easily carry out pneumatic construction with a high fluidity, and also to be able to directly use a chute, to absorb surplus water after construction, and to cause volume shrinkage Can be blocked.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram for explaining a construction method using an environmentally friendly geopolymer composition for stabilizing and strengthening a soft soil according to the present invention. FIG.
2 is a photograph showing a process of measuring intrusion resistance strength of an environmentally friendly geopolymer composition for stabilization and strength enhancement of a soft soil according to the present invention.
FIGS. 3 and 4 are photographs showing the flowability and compressive strength of the environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil according to the present invention.
5 is a photograph showing the process of measuring the bleeding occurrence amount and the volume variation of the environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil according to the present invention.

Hereinafter, the environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil according to the present invention will be described in detail.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

The environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil according to the present invention is blended with blast furnace slag powder, cement, anti-shrinkage agent, quick-setting admixture and alkaline activator.

First, blast furnace slag powder is preferably blended in an amount of 30 to 70% by weight. When the amount of the blast furnace slag powder is more than 70% by weight, the initial strength of the geopolymer composition is lowered. The effect of increasing the compressive strength by latent hydraulic properties is inferior. At this time, blast furnace slag powder should be suitable for KS F 2563 concrete blast furnace slag fine powder, and it is activated by the pozzolan reaction by the alkali active agent and the strength is expressed.

Blast furnace slag powder is obtained by pulverizing blast furnace slag generated during steel making and steel making process with a certain powder. It does not have hydraulic property in itself. However, when it is coexisted with alkaline material such as cement, it is considered as a hydraulically- . The latent hydraulic reaction of blast furnace slag powder usually starts after 7 days and contributes to the development of strength over a long period of time, so that the initial strength is lowered somewhat but the long term strength is increased. Since the initial reactivity of blast furnace slag powder is much smaller than that of cement, the replacement of blast furnace slag powder can reduce the amount of high-performance water reducing agent added for securing the required fluidity at the mixing stage and economical effect by recycling industrial by- The effect of improving the workability can be obtained owing to the increase in the volume of the binder due to the density difference due to the weight substitution with respect to the cement. In addition, blast furnace slag powder is used for the purpose of improvement of fluidity, improvement of long-term strength by potential hydraulic reaction and filling of pores.

It is preferable that the cement is mixed in an amount of 10 to 40% by weight. When the amount of the cement is more than 40% by weight, the effect of solving the environmental problem by using the blast furnace slag powder is reduced. The initial hydration reaction can not be sufficiently promoted, so that the initial strength can not be ensured and the stable improvement effect can not be exhibited. At this time, it is preferable that the cement is used either alone or mixed with one kind of portland cement or three kinds of crude steel cements.

), 과소생석회(dead-gurned lime, CaO), 무수석고중 선택된 어느 하나 또는 2개 이상을 혼합되어 사용되는 것이 바람직하다.If the amount is more than 30% by weight, the workability may be deteriorated. If the amount is less than 1% by weight, the effect of suppressing shrinkage may be weak. have. At this time, the anti-shrinkage agent is alpha-type hemihydrate (

), Dead-gurned lime (CaO), and anhydrous gypsum, or a mixture of two or more thereof.

Alpha-type semi-gypsum is divided into alpha (alpha) and beta (beta). The beta type is not generally used because it is late in condensation, and the alpha type can be used for mixed cement for molding and construction because of quick condensation. The amount to be used is preferably 1 to 10% by weight.

The under-burnt lime is produced by under-calcining calcined calcium oxide (CaO), and it prevents the volume shrinkage of the mixture by generating calcium hydroxide (Ca (OH) ₂ ) after the reaction without causing condensation due to the slow reaction rate with water Increase the calcium hydroxide (Ca (OH) ₂ ) concentration on the mixture. The amount used is preferably 5 to 20% by weight.

Anhydrous gypsum is divided into Ⅱ type anhydrite and Ⅱ type anhydrite (CaSO ₄ ). The Ⅱ type anhydrite can be obtained by heating the seasite (CaSO ₄ · 2H ₂ O) to about 450 ° C and the Ⅱ type anhydrous gypsum can be obtained by calcining at 900 ° C or more for 2 hours or more. Reactive in alkaline environment is Type II anhydrous gypsum, which reacts with aluminum oxide (Al ₂ O ₃ ) and calcium oxide (CaO) of cement, blast furnace slag powder and calcium aluminate to form acicular zeolite Thereby absorbing the surplus water of the mixture to reduce the volume change, and filling the capillary voids of the cured body to improve long-term strength and durability. The powder is also in the range of 200 to 600 m < 2 > / g and the usage is 10 to 30 wt%.

)를 급격하게 형성하게 되고, 에트링자이트는 상당한 잉여수를 흡수하여, 혼합물의 점성을 증가시키며, 블리딩수의 발생을 방지시킬 수 있다.In addition, the admixture is mixed when cement or under-buried lime is reacted with water to form a hydrate of calcium silicate hydrate (CSH) and calcium hydroxide (Ca (OH) ₂ )

), And the etching ring absorbs a considerable surplus water, increases the viscosity of the mixture, and can prevent the occurrence of bleeding water.

It is preferable that the quick-setting admixture is mixed in an amount of 1 to 10% by weight. At this time, it is preferable that the quick-setting admixture is used by mixing any one or two or more selected from calcium aluminate powder, calcium sulphoaluminate powder and alumina cement prepared using bauxite as a raw material.

The alkaline activator is preferably mixed in an amount of 0.1 to 5% by weight so as to accelerate the initial reaction of the blast furnace slag powder, anhydrous gypsum and Portland cement by rapidly increasing the alkali concentration of the environmentally friendly geopolymer composition. %, The workability and economical efficiency may be deteriorated. If the amount is less than 0.1 wt%, the effect of accelerating the initial reaction may be weak. At this time, it is preferable to use any one or two or more selected from sodium sulfate, sodium silicate and sodium hydroxide as a sodium-based alkaline activator in order to promote the reactivity of the geopolymer.

Hereinafter, a construction method using an environmentally friendly geopolymer composition for stabilizing and strengthening a soft soil according to the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram for explaining a construction method using an environmentally friendly geopolymer composition for stabilizing and strengthening a soft soil according to the present invention. FIG.

&Quot; Mixing process-S100 "

First, 5 to 30% by weight of an eco-friendly geopolymer composition is added to the mixer based on 100% by weight of the soil and 100 to 500% by weight of the eco-friendly geopolymer composition based on 100% .

&Quot; Feeding process-S 110 "

The mixture of soil and mixed water is transported to the site. At this time, it is preferable to transfer the mixed material from the mixer to the site by using a pump and a conveyance pipe, or to transfer it to the site by a conveyer truck.

&Quot; Installation process-S130 "

Subsequently, the transferred mixture is laid on the surface layer of the ground using a field chute.

&Quot; Curing process-S140 "

Finally, after completion of the installation, the mixture is cured.

Hereinafter, the features of the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

Table 1 shows composition ratios for verifying environmentally friendly geopolymer compositions for stabilization and strength improvement of soft soil according to the present invention. The test was mixed and measured quantitatively according to each composition ratio. Comparative Example-1 and Comparative Example-2 consisted of a mixture of ordinary Portland cement alone or a mixture of 60 wt% of ordinary Portland cement and 40 wt% of blast furnace slag powder. Examples 1- It is a composition ratio to grasp the characteristic of each used material.

2 is a photograph showing a process of measuring intrusion resistance strength of an environmentally friendly geopolymer composition for stabilization and strength enhancement of a soft soil according to the present invention.

In Comparative Example 1, the initial condensation proceeds considerably late, but the condensation progresses rapidly as time passes.

In Comparative Example 2, the initial condensation and the later condensation proceed very slowly. This is considered to be the effect of retarding the hydration of the mixture by using blast furnace slag powder at 40 wt% of the total mixed material.

Example 1 shows that blast furnace slag powder is used in an amount of 63 wt% of the mixed material without using ordinary portland cement and the balance is formed according to the present invention, and both of the initial coagulation and the latter coagulation are degraded.

Example-2 is a composition ratio of calcium aluminate and cement used as the precipitating minerals in Example-1, and the shrinkage inhibitor is not used. It can be seen that the initial and late condensation were considerably improved as compared with Example-1.

In Example 3, the composition ratio of the type II anhydrous gypsum in the shrinkage inhibitor was not used. By not using Ⅱ type anhydrous gypsum (CaSO ₄ ), condensation of the initial mixture is promoted, and early and late condensation are appeared most rapidly.

In Example 4 to Example 6, the intrusion resistance strength was measured by changing the kind of the alkaline activator.

Experimental results showed that all three materials promoted the hydration of the composition. Among them, sodium aluminate showed the best effect.

3 and 4 are graphs showing the flowability and compressive strength of the environmentally friendly geopolymer composition for stabilizing and strengthening the soft soil according to the present invention. to be.

Although the fluidity at all composition ratios is more than 200 mm, Comparative Example-1 and Comparative Example-2 show higher fluidity than Examples 1-6. The low fluidity in the composition ratio of the examples is a result of the initial fluidity deterioration caused by the shrinkage inhibitor, the triblock admixture and the alkaline activator in the materials used.

The compressive strength shows a similar relationship with the setting strength (48 hours).

Comparative Example-2, Example-3, Example-4, Example-5, and Example-6 in which the curing strength of 48 hours is high exhibit relatively high strength.

In Comparative Example 2, the strength of the blast furnace slag powder was lowered by 7 days after the late strength increase, but then the strength was increased significantly.

In Example-1, the initial and late strengths are both low, similar to the results of the condensation test.

 In Example-2, intensity expression was improved more than Example-1, but initial intensity was significantly lowered.

Example 3 exhibited excellent initial strength strength, but exhibited lower strength at later strength than other composition ratios (Examples -4 to 6).

Examples 4-6 measured the intensity expression results for differences in alkaline activators, and in Example 6, the initial and long term intensities were the best. In Example-4 and Example-5, the initial strength enhancement effect by alumina promotion and calcium silicate hydrate (CSH) formation was very large, but the improvement of long term strength was insufficient.

Table 4 shows the results of measurement of bleeding occurrence amount and volume change amount according to the composition ratio of the present invention. Figure 5 shows the amount of bleeding occurrence and volume change of the environmentally friendly geopolymer composition for stabilization and strength improvement of the soft soil according to the present invention . Fig.

In Comparative Example-1 and Comparative Example-2, a considerable amount of bleeding was generated, and the final volume change amounts were also as high as 5.2% and 6.4%, respectively.

However, in the Examples, the amount of bleeding was considerably reduced, and in Examples 3 to 6, no bleeding occurred. This shows that the use of a tacky admixture reduces the initial surplus water considerably and thus does not cause volume changes.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

Claims (11)

KS F 2563 Blast furnace slag powder for concrete 30 ~ 70 wt.% Blast furnace slag powder, 10 ~ 40 wt.% Cement used alone or mixed with 1 kind of portland cement or 3 kinds of crude steel cement, alpha type semicrystalline gypsum, 10 to 30% by weight of a shrinkage inhibitor mixed with any one or more selected from the group consisting of calcium aluminate powder, calcium sulfate aluminate powder and alumina cement, And 0.1 to 5% by weight of a sodium-based alkali active agent in which one or more selected from the group consisting of sodium sulfate, sodium silicate and sodium hydroxide are mixed, and a stabilizer for stabilizing and strengthening the soft soil Eco-friendly geopolymer composition. The method according to claim 1,
The eco-friendly,
Wherein the mixture is mixed with the gypsum and the mixed water in an amount of 5 to 30 wt% based on 100 wt% of the gypsum. 3. The method of claim 2,
The eco-friendly,
Wherein the mixed water is mixed with the gypsum and then mixed with 100 to 500 wt% of the mixed water based on 100 wt% of the environmentally friendly geopolymer composition. Polymer composition. delete delete delete delete delete delete The method of claim 1, wherein the environmentally friendly geopolymer composition is used for stabilizing and strengthening the soft soil,
5 to 30% by weight of the environmentally friendly geopolymer composition is added to the mixer based on 100% by weight of the gypsum, and 100 to 500% by weight of the mixed water is added based on 100% by weight of the geopolymer composition A process;
A transferring step of transferring the mixed mixed composition from the mixer to a site by using a pump and a transfer tube or by a ready-mixed transfer truck;
A laying process in which the transferred mixed composition is laid on the surface layer of the ground using a field chute; And
And a curing step of curing the mixed composition after the completion of the laying. The method of claim 1, delete

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