JP2003064618A - Improving material for soil pavement and execution method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improving material and an execution method of the same, which improves a soil ground so that it is prevented to get muddy, be eroded by rainwater, and to raise dust. SOLUTION: The improving material consists of a caking agent made of magnesium oxide and a granulating agent made of polyvinyl alcohol. The improving material is mixed into the soil ground to be improved at a ratio of 2.0 to 30.0 kg of magnesium oxide and 0.5 to 16.0 kg of polyvinyl alcohol per 1 m<3> of the soil ground. The ground to be improved, to which the improving material added, is agitated and mixed, then is laid over uniformly on a base layer 1 to form a surface layer 2 having a proper thickness. The surface layer 2 is sprinkled with water 3, if needed, and is compacted by a rolling, then is further sprayed with a surface treatment agent 4, according to a need.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for improving soil pavement used for improving the soil quality of surface soil such as grounds, plazas and parks, and a method of constructing the same.

[0002]

2. Description of the Related Art In order to improve weaknesses of soil-based pavements, such as mud and erosion, and dust buildup, various conventional methods have been used to add improvement materials to soil. ·Proposed. For example, a method of mixing slaked lime or sodium chloride with the ground surface soil is widely known. In addition, a method of mixing magnesium oxide or the like is proposed in JP-A-54-12152, and a method of mixing polyvinyl alcohol or the like is also disclosed in JP-A-62-162.
1907 and JP-A-2000-7926.

[0003]

However, any of the above-mentioned conventional methods for improvement has a defect and is not practically sufficient. That is, in the method of mixing slaked lime, the ground becomes too hard, and in the method of mixing sodium chloride, the soil is moisturized, so that a dustproof effect is obtained, but no effect on mudification or erosion is seen. Moreover, slaked lime is highly alkaline and sodium chloride is salinity,
There is a problem that adversely affects the surrounding fields and planting.
Further, the method of mixing magnesium oxide disclosed in JP-A-53-121525 is to soften the soil so that the athlete does not feel fatigue, and imparts water permeability to the soil. I can't. Also, JP-A-62-19
The method of mixing polyvinyl alcohol of No. 07 can be expected to have the effect of increasing the water resistance of soil, but it has poor strength against erosion resistance and is difficult to mix homogeneously with soil. There is. Further, JP 2000-
The method of mixing polyvinyl alcohol of No. 7926 can be expected to have a dust prevention effect, but since the mixing amount is large,
There is a problem that a film of polyvinyl alcohol is formed on the surface of the soil to impair the water permeability.

In view of the above points, the present invention can suppress the weaknesses of soil-based pavements, such as easy mud formation, easy erosion by rainwater, and easy dust buildup, and an environmentally friendly soil quality. The purpose is to provide a system-based pavement improvement material and a construction method thereof. Further, the present invention is to provide a soil-based pavement improving material which is excellent in workability and can maintain a soil improving effect for a long period of time, and a construction method thereof.

[0005]

Means for Solving the Problems The technical means of the soil-based pavement improvement material of the present invention comprises magnesium oxide as a solidifying agent and polyvinyl alcohol as an agglomerating agent, , Magnesium oxide, soil 1m
2.0 to 30.0 kg per ³ and polyvinyl alcohol 0.5 to 16.0 kg per 1 m ^{3 of} soil.

[0006] The amount of magnesium oxide is 1
It is preferably 5.0 to 20.0 kg per m ³ .
Furthermore, it is preferable that the blending amount of polyvinyl alcohol is 1.0 to 8.0 kg per 1 m ^{3 of} soil. Further, as another agglomerating agent for assisting polyvinyl alcohol, polyvinyl acetate powder emulsion, aluminum sulfate, polyaluminum chloride, sodium aluminate,
Iron sulfate, sodium polyacrylate, polyacrylamide,
It is preferable to blend one or more selected from the group consisting of polyoxin ethylene, polyethyleneimine, and quaternary ammonium salts. Furthermore, it is preferable to add 5.0 to 100 kg of incinerated ash as a moisturizing agent per 1 m ^{3 of} soil.

The technical means of the method for improving the soil-based pavement of the present invention is to add an improving material containing magnesium oxide and polyvinyl alcohol to the soil for soil-based improvement, and stir-mix the mixture so that there is no unevenness. After laying on the ground, it is to compact and roll.

Further, the improving material may be evenly dispersed on the local soil of the improvement target site, sufficiently stirred and mixed, and then spread. Further, the improving material may be added to the soil to be improved and mixed by stirring, and the mixed soil may be carried to the soil to be improved and spread. The layer thickness of the surface soil mixed with the improving material is preferably 30 mm or more. Further, water may be evenly sprayed from the spread surface soil, and then compacted and compacted. Further, the surface treatment agent may be evenly dispersed on the compacted surface soil.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the soil-based pavement improving material and the construction method thereof according to the present invention will be described below. In the present invention, magnesium oxide is used as a solidifying agent for developing soil to a required hardness and at an early stage. Magnesium oxide (MgO) has an effect of solidifying soil similarly to cement, and has a resolidifying action that cement does not have even if it is loosened after solidification. As magnesium oxide, those obtained by collecting and purifying from natural minerals, those purified by chemical elution from seawater, and the like have been submitted to the market, and therefore, they are appropriately selected and used. Usually, it is preferable to use crushed magnesia clinker having a magnesium oxide purity of 70% or more. The amount of magnesium oxide blended is 2.0 to 30.0 k per 1 m ^{3 of} soil in terms of 100% purity.
g, preferably 5.0 to 20.0 kg. Since magnesium oxide has been widely used as a raw material for medicines and fertilizers, it has little impact on the environment.

Further, in the present invention, as an agglomerating agent for enhancing the water resistance and water permeability by increasing the cohesive force between the soil particles to agglomerate the soil and create voids in the soil. Polyvinyl alcohol (PVA) is used. As the polyvinyl alcohol, it is preferable to use a powder having a saponification degree of 70 to 99% and a polymerization degree of 2400 or less. The blending amount of polyvinyl alcohol is 0.5 to 1 per 1 m ^{3 of} soil.
It is 6.0 kg, preferably 1.0 to 8.0 kg. It should be noted that polyvinyl alcohol is described in the standard for pharmaceutical additives and the standard for raw materials for cosmetics, is widely used in each field, and has extremely low toxicity.

In the present invention, the above polyvinyl alcohol may be used alone as the aggregating agent, or may be used as a mixture with another aggregating agent. As the aggregating agent which can be used, polyvinyl acetate powder emulsion which is the same water-soluble synthetic resin, or aluminum sulfate, polyaluminum chloride, sodium aluminate and sulfuric acid which are aggregating agents by the effect of agglomeration of fine particles. Iron, or one or more selected from the group consisting of sodium polyacrylate, polyacrylamide, polyoxyethylene, polyethyleneimine, and quaternary ammonium salts can be selected and used.

In the present invention, in addition to the above-mentioned solidifying agent and aggregating agent, a moisturizing agent may be used in order to suppress the drying of soil and enhance the dustproof effect. As a moisturizer, incineration ash such as paper sludge ash, coal ash, and refuse incineration ash are suitable because of their high porosity and high water retention. The amount of the moisturizing agent to be added is 5.0 to 100 kg, preferably 1 to ³ m ^{3 of} soil,
It is 10 to 30 kg.

The soil (aggregate) to be improved by the present invention includes natural soil such as soil and sand, processed aggregate such as Antuca and green stone, and recycled aggregate of waste.

The construction method of the present invention includes a local mixing method and a plant mixing method. The local mixing method is to uniformly spray the improving material of the present invention on the surface of the local soil of the improvement target site,
This is a method in which a tractor sufficiently mixes and mixes. Also,
The plant mixing method is a method in which the selected soil and the improved material are mixed and stirred by a mixer or the like at a factory, carried to an improved construction site, and spread by a bulldozer or a finisher. After this, both construction methods are the same, promptly compacting with a roller or the like and rolling, and if the soil water content is insufficient, sprinkle water appropriately. Next, a bulldozer or human power is used to level the surface, and the roller is compacted with a tire roller or the like to roll it. Finally, if necessary, a surface treatment agent is sprayed to finish the soil surface. FIG. 1 shows a cross section of a ground in a construction state, 1 is a base layer which is a lower layer roadbed, and 2 is a surface layer in which an improving material is mixed. The thickness H of the surface layer 2 is 30
It is preferable that it is not less than mm. Further, the water sprinkling 3 sprinkles an appropriate amount of water uniformly so that the soil is in an appropriate wet state. Further, as the surface treatment agent 4, bitter soup, sand or the like is suitable, and it is uniformly sprayed on the surface layer 2 at the end of construction.

Example 1 In Example 1, a solidifying agent (Mg
In order to know the proper blending amount of O), the blending amount of the agglomerating agent (PVA) was kept constant, and only the blending ratio of the solidifying agent was changed, and the results are shown in Table 1. There is. In addition,
Masago soil was selected as the soil to be improved. The amount of MgO blended is 1.0 to 40.0 kg (composition purity 100%) per 1 m ^{3 of} soil.
Change) range. PVA is 2.0 per 1 m ³ of soil
It was constant at kg. The mixed soil, which was prepared by adding the improving material to the soil to be improved and sufficiently stirred, was packed in a form frame of 100 cm in length and width and 10 cm in height to prepare a test piece, and various observations and tests were performed on the test piece. In addition, the amount of mixed soil to be packed is 0.14 m ³ so that the compaction density of the specimen becomes constant.
The water content ratio was set to 10% ± 1. In Table 1, ⊚ indicates excellent, ∘ indicates excellent, Δ indicates normal, ▲ indicates bad, and x indicates particularly bad. (The method of displaying the compounding amount and the method of preparing the specimen are the same in the following examples.)

[0016]

[Table 1]

As can be seen from Table 1, when the amount of MgO blended was 2.0 kg, the properties as a solidifying agent began to appear, and the hardness of soil increased. Moreover, when it exceeded 30.0 kg, it became too hard. Furthermore, it was confirmed that the resistance to frost heave in the cold was improved by mixing MgO. From the above results, the proper mixing amount of MgO is 2.0 per 1 m ^{3 of} soil.
It was found to be ~ 30.0 kg, preferably 5.0-20.0 kg.

Example 2 In Example 2, the aggregating agent (PV
In order to know the proper blending amount of A), this is an example in which the blending amount of the solidifying agent (MgO) was kept constant (7.0 kg) and only the blending ratio of the agglomerating agent was changed. 2 is shown. As the aggregating agent, powdered polyvinyl alcohol (saponification degree: 87.0 to 89.0%, polymerization degree: 200
No. 0) was used, and the compounding amount was changed in the range of 0.3 to 20.0 kg per 1 m ^{3 of} soil. The other points are the same as in the first embodiment.

[0019]

[Table 2]

As can be seen from Table 2, the compounding amount of PVA started to show the effect as the aggregating agent from around 0.5 kg, and the water permeability was improved. In addition, from around 16.0 kg, the resin adhered to the surface of the soil and the water permeability deteriorated. From the above results, the amount of PVA mixed is 1 m ³ of soil.
Per 0.5 to 16.0 kg, preferably 1.0 to
It was found to be 8.0 kg.

Example 3 In Example 3, the solidifying agent (Mg
The results are shown in Table 3 in which the amount of O) and the agglomerating agent (PVA) was changed together. Others are the same as in the first and second embodiments.

[0022]

[Table 3]

As can be seen from Table 3, the content of MgO is 2.0 to 30.0 kg, preferably 5.0 to 20.
kg and the amount of PVA compounded is 0.5 to 16.0 k
It has been found that an excellent improving effect is obtained in the range of g, preferably in the range of 1.0 to 8.0 kg. The improved soil that had been once compacted was loosened and then compacted again, and the aggregated structure was formed again and completely restored.

(Examples 4 and 5) Examples 4 and 5 are examples in which other agglomerating agents and moisturizers were added to the improving material, and the results are shown in Table 4 and It is shown in Table 5.
Aluminum sulphate was used as the other agglomerating agent, and mixed incineration ash of paper sludge ash (50%) and coal ash (50%) was used as the moisturizing agent. In addition, in Example 4, the compounding amounts of MgO and PVA were 7.0 and 7.0, respectively.
kg and 1.5 kg, and in Example 5, 14.
It was set to 0 kg and 3.0 kg. Others are the same as those in Examples 1 to 3.

[0025]

[Table 4]

[0026]

[Table 5]

In Tables 4 and 5, the hardness was determined by the Proctor needle test in which the penetrating needle was pierced against the ground. The moisturizing property was determined by the time required for the surface to become dry and whitish after a constant wetting. The determination of the submerged condition was conducted by visually observing the float of the silt and tentacles in the submerged condition. After the submersion, the foot test is judged 4
After being submerged for 5 minutes and left unsubmerged for 15 minutes, the foot twist test after the submergence depends on the depth of the foot mold attached to the specimen. Becomes
It depends on the degree of soil collapse when twisted 90 °. The recoverability after submergence was determined by a hardness test before and after submergence. The water permeability was determined by the amount of water permeation during a certain period of time in a flooded state.

As can be seen from Tables 4 and 5, when aluminum sulfate is added, it not only assists the agglomeration action well,
The effect of agglomeration reaction was accelerated and the ground was stabilized early. With the addition of a moisturizer, the effect of maintaining the soil moist condition for a long time was observed. Further, it has been found that the one to which both aluminum sulfate and the moisturizer are added has a good balance of the performance of the improved soil and is very excellent for a ground.

The present invention is not limited to the above embodiments, but can be freely modified within the scope of the claims. In particular, the soil to be improved may be any soil type soil and can be freely selected. Further, the present invention can be used in a wide variety of applications other than grounds.

[0030]

When the improved material of the present invention is used, magnesium oxide is mixed as a solidifying agent, so that the gland or the like can be adjusted to a desired hardness. In addition, since polyvinyl alcohol is blended as the aggregating agent, the soil particles are bonded to each other to form an aggregated structure, and the water permeability is increased,
The drainage is improved, the soil particles are less likely to be eroded by rainwater due to the binding force, and dust is less likely to be generated during drying. Furthermore, it can suppress mudification after rainfall, and even if it becomes mud, it will recover quickly. Also, since it has a recombination force, it is possible to restore a collapsed ground or the like with a simple work. Further, in the present invention, since the cement-based solidifying agent is not used, problems such as elution of hexavalent chromium and high alkali are not caused, and the surrounding environment is not harmed.

According to the second aspect of the present invention, the content of magnesium oxide is more specified, so that the hardness of the gland and the like can be improved to a more preferable state.

According to the third aspect of the invention, since the blending amount of polyvinyl alcohol is more specified, the formation of the aggregated structure can be further enhanced.

According to the present invention, since another agglomerating agent is used as an auxiliary, in addition to improving the aggregating action, it is possible to accelerate the agglomerating reaction and stabilize the ground surface early. The effect of can be expected.

According to the fifth aspect, since the incinerated ash is mixed as the moisturizing agent, the water retaining capacity of the soil is enhanced, the moisture retaining property of the entire surface soil is improved, and the dustproof effect can be enhanced. Furthermore, since incinerated ash is used, it can contribute to the reuse of recycled resources.

According to the improved construction method of the present invention, the soil for soil improvement can be improved by a simple operation into an excellent pavement soil which is unlikely to be mud-damaged, is not easily eroded by rainwater, and is free from dust.

According to the seventh aspect of the present invention, since the local soil is used, it is possible to minimize the generation of construction residual soil and prevent the occurrence of traffic stress due to the loading and unloading of soil.

According to the eighth aspect of the present invention, since the mixed soil to which the improving material is added is carried into the site, the construction quality can be maintained easily and the construction period can be shortened.

According to the ninth aspect, since the layer thickness of the surface soil is specified, the improved characteristics do not easily disappear in a short period of time, and the stability of the ground can be improved.

According to the tenth aspect, since water is sprinkled before compaction, the degree of wetness of the soil can be properly adjusted, and the improvement effect can be reliably generated.

According to the eleventh aspect, since the surface treating agent is used, the surface characteristics of the ground can be improved to a better condition.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an improved enforcement method of the present invention.

[Explanation of symbols]

1 base layer 2 surface 3 water 4 Surface treatment agent

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[Procedure amendment]

[Submission date] January 23, 2002 (2002.1.2
3)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Continued front page    F term (reference) 2D040 AA08 AB07 AB11 BA11 CA10                       CB01 CD07                 2D051 AB04 AC10 AD08 AF01 AF04                       AF11 AG15 AG17 AG20 AH02                       AH03 EA01 EA06 EB02 EB06

Claims (11)

[Claims] 1. Soil containing magnesium oxide as a solidifying agent and polyvinyl alcohol as an agglomerating agent, and magnesium oxide per 1 m ^{3 of} soil to the soil for soil improvement
A soil-based pavement improver containing 2.0 to 30.0 kg and polyvinyl alcohol in an amount of 0.5 to 16.0 kg per 1 m ^{3 of} soil. 2. The amount of magnesium oxide mixed is 1 m ^{3 of} soil.
The soil-based pavement improver according to claim 1, which has a weight of 5.0 to 20.0 kg. 3. The blending amount of polyvinyl alcohol is 1
The soil-based pavement improver according to claim 1, which has an amount of 1.0 to 8.0 kg per m ³ . 4. A polyvinyl acetate-based powder emulsion, aluminum sulfate, polyaluminum chloride, sodium aluminate, iron sulfate, sodium polyacrylate, polyacrylamide, as another agglomerating agent for assisting polyvinyl alcohol. The soil-based pavement improver according to claim 1, which comprises one or more selected from the group consisting of polyoxin ethylene, polyethyleneimine, and quaternary ammonium salts. 5. The soil-based pavement improver according to claim 1, wherein incineration ash as a moisturizing material is mixed in an amount of 5.0 to 100 kg per 1 m ³ of soil. 6. A soil-improving soil, to which an improving material containing magnesium oxide and polyvinyl alcohol is added,
An improved construction method for soil-based pavement that mixes with stirring, spreads it so that it is not uneven, and then compacts and rolls it. 7. The method according to claim 6, wherein the improving material is evenly dispersed on the local soil of the improvement target area, sufficiently stirred and mixed, and then spread.
The improved construction method for the soil-based pavement described. 8. The improvement soil is added to the improvement soil, the mixture is stirred and mixed, and the mixed soil is conveyed to the improvement soil and spread.
The improved construction method for the soil-based pavement described. 9. The layer thickness of the surface soil mixed with the improving material is 30 m.
The improved construction method for soil-based pavement according to claim 6, wherein the pavement is m or more. 10. The improved construction method for a soil-based pavement according to claim 6, wherein water is uniformly sprinkled on the spread surface soil and then compacted and compacted. 11. The method for improving construction of a soil-based pavement according to claim 6, wherein the surface treatment agent is uniformly sprayed on the compacted surface soil.