KR102535413B1 - Method for strength improvement of soil using zein, composition and construction materials using the same - Google Patents

Abstract

The present invention relates to a method for preparing a composition for reinforcing ground strength. The method for preparing a composition for reinforcing ground strength includes preparing zein and sand (S1); Preparing a solvent containing water, ethanol and polyethylene glycol (S2); mixing the zein, sand and solvent (S3); and dehydrating the solvent (S4).

Description

Method for strength improvement of soil using zein, composition and construction materials using the same {Method for strength improvement of soil using zein, composition and construction materials using the same}

The present invention relates to a ground strength reinforcement method using zein, a composition and a building material using the same.

In general, unstable soils have low strength and high compressibility. These characteristics have problems of causing loos of bearing capacity, differential settlement and lateral movement during shear loading. To improve this, chemical and mechanical stabilization techniques have been used. As a chemical stabilization technique, a chemical binder associated with soil modification through surface reaction is generally used. Binders widely used for soil stabilization in geotechnical engineering include lime and Portland cement. However, traditional binders have a problem of discharging carbon dioxide, a major greenhouse gas, into the atmosphere during the manufacturing process.

Environmentally friendly cementitious materials, such as the induction of calcium carbonate precipitation using microorganisms or urease, have recently been introduced as potential soil stabilizers due to their sustainability and efficiency compared to conventional binders. However, there are limitations such as the inability to apply the material to fine-grained soil due to the size of bacteria.

Zein is the protein part of corn endosperm, which makes up about 44-79% of corn, and has adhesive and self-stabilizing properties. It is known that the hydrophobicity of zein is related to many non-polar amino chains. In addition, zein has been used in tissue engineering to increase the tissue interaction of bone scaffolds and has been used to adhere to the walls of food preservation and microbial sensitive pharmaceuticals. These zein biopolymers are predicted to serve as potential binders to improve the geotechnical properties of soils due to interparticle bonding, non-toxicity to soils and surrounding environments, biodegradability, and low interaction with water.

Accordingly, there is a need for a ground strength reinforcement method using an environmentally friendly material capable of solidifying fine particles.

In order to solve the above problems, the present invention provides a ground strength reinforcement method using zein, which has never been used in geotechnical engineering. In order to examine the effect of zein on sand, the amount of zein was adjusted and the curing period of the samples added with zein was varied.

However, the problem to be solved by the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

According to one embodiment of the present invention, preparing jain and sand (S1);

Preparing a solvent containing water, ethanol and polyethylene glycol (S2);

mixing the zein, sand and solvent (S3); and

It provides a method for preparing a composition for reinforcing ground strength, comprising the step of dehydrating the solvent (S4).

According to one side, a composition for reinforcing ground strength prepared by the above manufacturing method is provided.

According to another aspect, a building material or member including the composition for reinforcing ground strength is provided.

The ground strength reinforcing method of the present invention can connect the fine particles, thereby improving the strength of the ground. In addition, by using eco-friendly materials, it can be used as an alternative reinforcing agent for existing binders for carbon neutrality.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a diagram showing a process of preparing a solvent for Jane.
Figure 2 is a diagram showing the reaction mechanism of dissolution of zein for strength improvement.
3 is a diagram showing a stress-strain diagram according to particle size distribution.
Figure 4 shows a stress-strain diagram according to the zein content.
5 is a stress-strain diagram according to the curing period.
6 shows a comparison of uniaxial compressive strength results according to curing period and zein content of samples of Examples and Comparative Examples.
Figure 7 compares the results of the secant modulus according to the curing period and the content of zein of the samples of Examples and Comparative Examples.
Figure 8 shows the relationship between the uniaxial compressive strength and the elastic modulus of the sample treated with zein.
9 shows the relationship between uniaxial compressive strength and uniformity coefficient.
10 shows a scanning electron microscope image in which zein was added to a sample of Example 1.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes can be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents or substitutes to the embodiments are included within the scope of rights.

Terms used in the examples are used only for the purpose of explanation and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiment belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, it should not be interpreted in an ideal or excessively formal meaning. don't

In addition, in the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted. In describing the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term.

Components included in one embodiment and components including common functions will be described using the same names in other embodiments. Unless stated to the contrary, descriptions described in one embodiment may be applied to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components rather than excluding other components.

Throughout the specification, the cementation or cementation effect refers to an action in which separated sediment particles harden together with a decrease in porosity due to the precipitation of a cementing material to form sedimentary rocks.

Throughout the specification, unconfined compressive strength (UCS) means the maximum axial compressive stress that a sample can withstand when the confining stress is zero.

Throughout the specification, the secant modulus of elasticity (E ₅₀ ) means the slope of a line connecting the origin and a designated point (eg, yield point) on a stress-strain diagram. It is used to describe the stiffness of a material in a stress-strain diagram.

According to one embodiment of the present invention, it is possible to provide a method for preparing a composition for reinforcing ground strength. The manufacturing method includes preparing zein and sand samples (S1); Preparing a solvent containing water, ethanol and polyethylene glycol (S2); mixing the zein, the sand sample and the solvent (S3); and dehydrating the solvent (S4).

In step S1 of an embodiment of the present invention, the content of the zein may be 1 to 5% by weight based on the total weight of the sand sample.

When the content of zein is less than 1% by weight based on the total weight of the sand sample, there may be a problem in that the compressive strength is not sufficiently expressed. On the other hand, if the content of zein exceeds 5% by weight based on the total weight of the sand sample, there may be a problem with economic feasibility when applied in the field.

In step S1 of an embodiment of the present invention, the sand sample may include silica sand and silt.

The weight ratio of the silica sand and the silt may be 1:9 to 9:1.

In step S1 of an embodiment of the present invention, the uniformity coefficient of the sand sample may be 2 to 14, preferably 2.5 to 13.5, and more preferably 2.8 to 13.1. Most preferably, it may be 11.2 to 13.1, but is not limited thereto.

In the manufacturing method according to an embodiment of the present invention, the volume ratio of ethanol, water, and polyethylene glycol in step S2 may be 4:5:1. Ethanol and water are used to improve the solubility of zein. Polyethylene glycol is chosen as the superplasticizer to improve the adhesion of the zein. The solvent is stirred for 1 to 10 minutes to obtain a stable solution (FIG. 1).

Step S4 of an embodiment of the present invention includes exposing the polar amino group of zein to distilled water by reacting the solvent with the non-polar amino group of zein (a1); and combining with the solvent-exposed zein to form zein nanoparticles (a2); may include (FIG. 2).

In the manufacturing method according to an embodiment of the present invention, step S4 may be characterized in that the solvent combines with the exposed zein to have a caking phenomenon.

Hereinafter, the step S4 will be described in detail. Zeins are amphiphilic and can consist of 50% or more non-polar amino acids. Zein cannot be dispersed in pure water, but can be easily dispersed in an aqueous solution containing 60-95% ethanol. Ethanol can lower the polarity of an aqueous solution. In the mixture of zein and solvent, ethanol and polyethylene can react with the non-polar amino groups of zein, exposing the polar amino groups of zein to distilled water. The solvent in the mixture can combine with the exposed amino groups to form large zein nanoparticles with a cementation effect. During the dehydration process, the solvent gradually evaporates, which enhances the zein's consolidation. The induced consolidation can show an increase in the protein network and hydrophobic interactions between the zein molecule and the functional structure.

According to another embodiment of the present invention, it is possible to provide a composition for reinforcing ground strength prepared by the above manufacturing method.

The uniaxial compressive strength of the composition for reinforcing ground strength may be 5 to 3100 kPa, preferably 7 to 3070 kPa, and more preferably 10 to 3065 kPa. Most preferably, it may be 50 to 3065 kPa.

The modulus of elasticity of the composition for reinforcing ground strength may be 0.3 to 140 MPa, preferably 0.35 to 130 MPa, and more preferably 0.4 to 122.6 MPa. Most preferably, it may be 3 to 122.6 MPa.

However, it is not limited to the described range.

The use of the composition for reinforcing ground strength may further include any one of erosion prevention, permeability reduction, and vegetation germination.

The composition can be cured for 3 to 28 days. If the curing period is less than 3 days, there is a possibility that the uniaxial compression test cannot be performed due to insufficient strength development depending on the content of zein.

According to another embodiment of the present invention, a building material or member including the composition for reinforcing ground strength may be provided.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of rights of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents or substitutes to the embodiments are included within the scope of rights.

Example 1

Sand samples containing silt and silica sand were prepared. At this time, the content of silt was 50% by weight based on the total weight of the sand sample.

Example 2

It is the same as in Example 1, except that the content of silt is 30% by weight relative to the total weight of the sand sample.

Comparative Example 1

It is the same as in Example 1, except that the content of silt is 10% by weight relative to the total weight of the sand sample.

Comparative Example 2

It is the same as in Example 1, except that the content of silt is 70% by weight based on the total weight of the sand sample.

Comparative Example 3

It is the same as in Example 1, except that the content of silt is 90% by weight based on the total weight of the sand sample.

Experimental Example 1: Preparation of Examples and Comparative Examples and Preparation for Experiments

Experimental Example 1-1: Preparation of Jane

Commercial zein is extracted from maize kernels using benzene or ether solutions to remove oil and fatty substances.

Experimental Example 1-2: Sand sample preparation

Grain size distribution curves of Examples 1, 2 and Comparative Examples 1 to 3 were obtained from sieve analysis according to ASTM D6913/D6913M (ASTM D6913, 2017).

Particle size distribution characteristics of Examples and Comparative Examples are shown in Table 1 below. Here, D ₅₀ is the mean diameter, and D ₁₀ , D ₃₀ , and D ₆₀ are the particle sizes of 10, 30, and 60% passage, respectively. C _u is the coefficient of uniformity, C _c is the coefficient of curvature, #200 [%] is the rate passing through the No. 200 sieve, G _s is the specific gravity and USCS ( unified soil classification system) means a unified classification method for classification of soil.

division D ₁₀ D ₃₀ D ₅₀ D ₆₀ C _u C _c #200 [%] G _s USCS Example 1 0.07 0.24 0.67 0.80 11.2 1.0 14.6 2.67 SM Example 2 0.09 0.56 1.01 1.21 13.1 2.8 9.6 2.64 SW-SM Comparative Example 1 0.32 0.80 1.15 1.32 4.1 1.5 4.3 2.63 SW Comparative Example 2 0.09 0.23 0.59 0.72 8.0 0.8 13.1 2.69 SM Comparative Example 3 0.08 0.13 0.19 0.22 2.8 1.0 13.4 2.69 SM

The specific gravity of Examples and Comparative Examples was 2.63 to 2.69, and the average diameter was 0.19 to 1.15 mm. The uniformity coefficient was 2.8 to 13.1, and the distribution of particle sizes was the widest in Examples 1 and 2. In order to investigate the compaction properties of Examples and Comparative Examples, a compaction test was conducted according to ASTM D698 (ASTM D698, 2012). The maximum dry unit weight and optimum moisture content of Examples and Comparative Examples are shown in Table 2.

division dry unit weight (kN/m ³ ) Optimal water content (%) Example 1 20.5 10.3 Example 2 19.8 13.2 Comparative Example 1 20.1 10.4 Comparative Example 2 19.9 11.5 Comparative Example 3 17.2 10.4

Experimental Example 1-3: Mixing Process of Jane and Sand

In order to investigate the effect of zein on the mechanical properties of soil, samples treated with zein were prepared in the following manner.

Each of the sand samples treated with zein contained commercial zein and sand according to Examples and Comparative Examples, and zein was added at 1, 3 and 5% by weight relative to the total weight of the sand. To make a uniform mixture of zein and sand, the zein and sand were mixed for 5 minutes.

The solvent contained 99% ethanol, distilled water and polyethylene glycol, and the volume ratio of ethanol, distilled water and polyethylene glycol was 4:5:1. Stirring was continued for 1 to 5 minutes to make a stable solvent.

The zeined sample was mixed with the solvent at the optimum water content using an automatic mixer.

Experimental Example 1-4: Sample preparation

All samples are prepared by being compacted into a cylindrical shape in a detachable MC-nylon mold. In order to reduce the gap between each sample, 25 blows per layer were applied with a hammer of 5.4 N in a layer of three different uniform samples. All the compacted samples were demolded after curing for 2 days at room temperature and cured for a targeted period of time under a temperature of 40 °C and a humidity of 30% in an adiabatic chamber.

Experimental Example 1-5: Preparation for uniaxial compression test

The compressive strength and modulus of elasticity of all samples were investigated by uniaxial compression test after curing the samples for 3, 7 and 28 days. This test was performed on cylindrical samples according to ASTM D2166 (ASTM D2166, 2006). An axial load was applied to the top of each sample at a loading rate of 1 mm/min, up to an axial strain of 5%.

Experimental Example 2: Stress-strain curves of Examples and Comparative Examples

A stress-strain diagram is a graph obtained by measuring the load and strain applied to a specimen of a material. In general, the axial stress increases as the axial strain increases initially, and then reaches the maximum compressive stress, which is determined as the uniaxial compressive strength. After that, the compressive stress decreases as the axial strain further increases.

1. Stress-strain diagram according to particle size distribution

The stress-strain diagram results of the samples of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in FIG. 3 . At this time, 3% by weight of zein was added to each sample based on the total weight of sand, and the stress-strain relationship was confirmed after curing (a) 3 days and (b) 28 days.

Uniaxial compressive strength was found to be the highest in Examples 1 and 2.

2. Stress-strain diagram according to zein content

Example 1 Samples were added with 1, 3, and 5% by weight of zein based on the total weight of sand, and the results are shown in FIG. 4 . (a) is the stress-strain result when the curing period is 3 days and (b) is the curing period is 28 days.

In Example 1, the uniaxial compressive strength increased as the zein content increased.

3. Stress-Strain Diagram with Curing Time

Example 1 After curing the samples for 3 days, 7 days, and 28 days, the stress-strain relationship is shown in FIG. 5 . Zein was added in an amount of 5% by weight based on the total weight of sand.

In Example 1, the uniaxial compressive strength increased as the curing time increased.

Experimental Example 3: Uniaxial compressive strength and secant modulus

1. Uniaxial compressive strength

The uniaxial compressive strength according to the zein content and curing period of all examples and comparative samples is shown in FIG. 6 . (a), (b) and (c) are the results when the content of zein was 1% by weight, 3% by weight and 5% by weight, respectively, based on the total weight of sand.

In all samples, the uniaxial compressive strength increased as the zein content increased. The addition of zein causes a phenomenon of consolidation of sand particles (Fig. 2). This is because as the content of zein increases, more interparticle bonding, including fine particles, is induced.

In addition, in all samples, the uniaxial compressive strength increased as the curing period increased. This is expected to be due to the effect of increasing the size of the solidified particles due to the dehydration of the solvent as the curing period is longer.

When the zein content was 1 to 5% by weight relative to the total weight of the soil, after curing for 28 days, the uniaxial compressive strength values of Examples 1 and 2 were the highest. From this, it can be predicted that the number and size of the solidified particles of Examples 1 and 2 increased the most.

2. Modulus of elasticity

The secant modulus at the stress and strain points corresponding to 50% of the compressive strength according to the zein content and the curing period of all the examples and comparative examples are shown in FIG. 7 . (a), (b) and (c) are the results when the content of zein was 1% by weight, 3% by weight and 5% by weight, respectively, based on the total weight of sand.

As the zein content increased, the modulus of elasticity increased. This is explained by the fact that as the zein content increases, the sample becomes more electrostatically stable and bio-filling is formed between the silt and the sand.

The longer the curing period, the higher the modulus of elasticity. When the sample treated with zein was cured for 28 days, the stiffness was improved by more than 500% compared to the sample cured for 3 days.

3. Relationship between uniaxial compressive strength and elastic modulus

The relationship between the uniaxial compressive strength and the modulus of elasticity of the sample treated with zein is shown in FIG. 8 . Irrespective of the zein content and curing period, the uniaxial compressive strength increased as the elastic modulus increased.

4. Uniaxial compressive strength and the coefficient of uniformity of the sample

The relationship between uniaxial compressive strength (q _u ) and uniformity coefficient (C _u ) is as follows.

The relationship between the uniaxial compressive strength and the uniformity coefficient when the content of zein is 3% by weight relative to the total weight of sand is shown in FIG. 9 and Table 3 below. From this, it can be seen that the rate of increase in strength induced by zein increases as the uniformity coefficient of the sample increases.

Curing period [days] slope, α coefficient of determination, R ² 3 39.59 0.974 7 52.28 0.949 28 60.80 0.969

Experimental Example 4: Microscopic Interaction

Example 1 A scanning electron microscope image in which zein was added to the sample is shown in FIG. 10 . (a) and (b) are the results when the content of zein is 1% by weight and 5% by weight based on the total weight of sand, respectively.

The zein covers the sand grains, connecting the fine and coarse grains in the mixture and filling the pores. According to FIG. 10(a), when 1% zein was added, bio-clogging was caused in the sand mixture by mainly connecting fine particles. According to FIG. 10(b), increasing the content of zein enhances the interaction between fine and coarse particles.

The wide particle size distribution of the sand of Example 1 enhances the interparticle bonding of the zein-treated sample and consequently accelerates the electrosteric stabilization of the sample through an increase in the protein-protein network of the zein. In addition, as the content of zein increases, the size of the solidified particles increases, which increases the elastic modulus and compressive strength of the zein-treated sample. This is related to the cementing effect of the zein between the fine and coarse particles in the mixture.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Claims (13)

Preparing Jane and Sand (S1);
Preparing a solvent containing water, ethanol and polyethylene glycol (S2);
mixing the zein, sand and solvent (S3); and
Including; dehydrating the solvent (S4);
In step S4,
exposing the polar amino group of the zein to distilled water by reacting the solvent with the non-polar amino group of the zein (a1); and
A step (a2) of forming zein nanoparticles by combining with the solvent-exposed zein;
The step S4 is characterized in that the zein nanoparticles have a solidifying effect of sand, a method for producing a composition for reinforcing ground strength.
delete delete According to claim 1,
In the step S1, the content of the zein is 1 to 5% by weight based on the total weight of the sand, the method for producing a composition for reinforcing ground strength.
According to claim 1,
In step S1, the sand includes silica sand and silt, a method for producing a composition for reinforcing ground strength.
According to claim 5,
The weight ratio of the silica sand and the silt is 1:9 to 9:1, a method for producing a composition for reinforcing ground strength.
According to claim 1,
In the step S1, the uniformity coefficient of the sand is 2 to 14, a method for producing a composition for reinforcing ground strength.
According to claim 1,
The volume ratio of ethanol, water and polyethylene glycol in step S2 is 4: 5: 1, a method for producing a composition for reinforcing ground strength.
A composition for reinforcing ground strength prepared by any one of claims 1 and 4 to 8.
According to claim 9,
The uniaxial compressive strength of the composition for reinforcing ground strength is 5 to 3100 kPa, the composition for reinforcing ground strength.
According to claim 9,
The elastic modulus of the composition for reinforcing ground strength is 0.3 to 140 MPa, the composition for reinforcing ground strength.
According to claim 9,
The use of the ground strength reinforcing composition further comprises any one of erosion prevention, permeability reduction and embankment reinforcement, ground strength reinforcing composition.
A building material or member comprising the composition for reinforcing ground strength of claim 9.

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