JP2897476B2 - Aqueous soil conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrous soil conditioner. Details of construction residual soil generated with the construction and civil engineering (hereinafter, referred to as "surplus soil") was soil improvement, to an improved agent for construction waste soil suitable for achieving reuse as resources.

[0002]

2. Description of the Related Art Conventionally, most of the remaining soil generated in various places is
Although they cannot be reused and are disposed of in landfills or transported to other places, there are considerable illegal dumping, which has been highlighted as a problem of environmental destruction. This is because the amount of surplus soil generated is rapidly increasing due to active redevelopment projects, etc., but the number of sea reclamation works is decreasing, making it difficult to secure a place for receiving surplus soil.

[0003] Also, for backfilling the excavated site,
The law stipulates that sand be used. Therefore, for backfilling, it is generally necessary to bring mountain sand from other places, and the problem of environmental destruction is also occurring here. Regarding the reuse of the remaining soil generated in such a situation, there is an example in which a test plant for processing the remaining soil using quicklime is operated.

[0004]

The method of the test plant described above is intended for only high-quality residual soil, and is improved for residual soil with a low moisture content due to the large size of the site. When considering an improved plant, the site cannot be widened, so the residual soil with a high water content generated on site must be improved without drying it in the sun, and soil with such a high water content has a large tackiness. However, there is a problem in that it adheres to a mixer or the like, makes the operation difficult and cannot be processed.

[0005]

Means for Solving the Problems The present inventors have solved the problems of the prior art, a result of intensive studies to obtain an excellent modifier relates reuse surplus soil, and (A) hydraulic cement
(B) stone or or (A) hydraulic cement and (B) raw
The present inventors have found that by using lime or limestone and the water-soluble polymer (C) in a specific ratio in combination, the hydrated soil of the construction residual soil can be reused for backfilling, and arrived at the present invention.

That is, the gist of the present invention is to provide (A) a hydraulic cement
And (B) stone stone, and (B) /
(A) 0.1 to 20 in the construction surplus soil improving agent,
You. Another gist of the present invention is that (A) a hydraulic cement
And (B) quicklime or masonry, and (C) a water-soluble polymer
And (B) / (A) is from 0.1 to 20 in weight ratio.
And the water-soluble polymer accounts for 0.1 to 20% by weight of the whole.
Improvement agent for construction surplus soil . Hereinafter, the present invention will be described in detail. The improvement of construction residual soil in the present invention means that, in order to re-use soft or highly wet hydrated soil for backfilling, etc., while improving the strength, imparting fluidity like sand, and swelling in water That is, the solidification treatment is performed to the extent that it is not performed. Therefore, the improvement of the construction surplus soil in the present invention does not mean that the hydrous soil is simply solidified into a solid state and the fluidity is lost.

The hydraulic cement used in the improver of the present invention is a cement which hardens in air and water,
For example, portland cement, alumina cement, jet cement, silica cement and the like can be mentioned.
As quicklime, in addition to those that are generally commercially available, use those obtained by burning and crushing the shells of fish and shellfish generated from the general food industry and households, and the shells attached to the cooling pipes of power plants and the like. You can also.

[0008] The stone is preferably anhydrous stone, but hemihydrate stone may also be used. The improving material for hydrous soil of the present invention comprises the above (A) hydraulic cement and (B)
Masonry or (A) hydraulic cement and (B) quicklime or
It consists gypsum and (C) a water-soluble polymer, in a weight ratio (B) / (A) 0.1~20 , preferably 0.3 to 1
0, more preferably 0.5 to 5.

[0009] Portland cement, which is the most common hydraulic cement, mainly mixes a calcareous raw material and a clayey raw material at an appropriate ratio and melts and calcinates the clinker. The product is finely pulverized after mixing as a setting speed regulator to obtain a product. Therefore, the cement is composed of a solid solution of CaO, SiO ₃ , Al ₂ O _3, etc. and several percent of a stone component.

However, when the residual soil (hydrous soil) is improved in a plant, the use of the hydraulic cement alone is not suitable because the residual soil cannot be hardened in a short time. However, in the case of the improver of the present invention, when hydraulic cement and quick lime and / or masonry stone are used together in the above-described ratio, the synergistic effect of promoting the hardening reaction of the hydraulic cement is unexpectedly surprising. This is recognized, and specifically, an improved soil with increased CBR strength and good fluidity is obtained.

Further, a water-soluble polymer, a superabsorbent polymer and the like can be appropriately added to the improver of the present invention, and it is particularly preferable to use a water-soluble polymer in combination. Such a water-soluble polymer is generally a polymer soluble in at least 1 g in 100 ml of water, and is generally a (meth) acrylamide homopolymer or a copolymer thereof.

The copolymer is preferably one having a carboxyl group as a hydrophilic group. In particular, among all monomers constituting the polymer, a monomer having a carboxyl group is usually 1 to 80. Mol%, preferably 5 to 60 mol%. Also, the carboxyl group may be present in either the free acid or salt form. Examples of the type of salt include salts of alkali metals such as sodium and potassium, salts of alkaline earth metals such as calcium and magnesium, ammonium salts, amine salts such as alkylamines having 1 to 18 carbon atoms, alkanolamines, and the like. There is a mixture of two or more, but preferably a salt of an alkali metal.

Examples of the water-soluble polymer having a carboxyl group include a (meth) acrylamide-based polymer containing (meth) acrylic acid or a salt thereof, a copolymer of maleic acid or a salt thereof and vinyl acetate, and itaconic acid. Alternatively, there is a copolymer of a salt thereof and (meth) acrylamide, and a (meth) acrylamide polymer containing (meth) acrylic acid or a salt thereof is preferable. (Meta)
Examples of the acrylamide-based polymer containing acrylic acid or a salt thereof include (meth) acrylic acid or a salt thereof and a copolymer of (meth) acrylamide and (meth) acrylic acid.
Acrylamide may be partially hydrolyzed. Moreover, what was copolymerized combining the monomers shown above may be sufficient.

Further, a monomer containing a sulfonic acid group as a hydrophilic group, for example, vinyl sulfonic acid,
Copolymers including allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and salts thereof may be used. In addition, a hydrophobic monomer such as an olefin, an acrylate or a vinyl ester may be contained as long as the water solubility is not impaired.

The molecular weight of the water-soluble polymer used in the present invention is usually 1,000,000 or more, preferably 5,000,000 or more. Although the production method is not particularly limited, it is generally a radical polymerization method, and particularly, solution polymerization using water or a lower alcohol as a solvent is employed. The obtained water-soluble polymer is directly dried in a drier or treated with a dehydrating agent, and then dried and pulverized before use. The amount of the water-soluble polymer added to the hydraulic cement of the present invention and the modifier composed of quicklime and / or masonry is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight of the whole modifier. %.

The soil to be used in the present invention is usually a soil having a water content of 20% or more. Particularly, the use of the improver of the present invention can be expected in soils having a high water content of about 40 to 200%, and more preferably about 60 to 150% in water content. Soil generated by general civil engineering and construction work, such as residential land development work (construction residual soil)
It is. The water content is a value obtained by expressing the ratio of the mass of soil water lost by oven drying at 100 ° C. to the mass of the soil dried in oven as a percentage, and is a value measured by JISA1203 (water content test method). It is.

The soil includes a loam layer, gravel, earth and sand, and is usually a mixture thereof. However, depending on the generation site, concrete pieces may be mixed. Since the water content differs depending on the soil properties, it largely depends on the site where the water is generated. Those having a high water content include, for example, the Kanto loam layer, which usually shows a water content of about 80 to 120% and has high tackiness, but is solidified and granulated by using the improver of the present invention. Fluidity is imparted, there is no tackiness and no swelling in water, the ground support is improved, and backfilling can be made possible.

The addition amount of the improver of the present invention is not particularly limited because it differs depending on the water content of the soil to be treated, but the addition amount of hydraulic cement to the residual soil is usually 0.2 to 50% by weight, preferably, 0.2 to 50% by weight. 0.5 to 30% by weight, the addition amount of quicklime and / or masonry is 0.2 to 20% by weight, preferably 0.5 to 10% by weight, and the water-soluble polymer is
Usually 0.01 to 1% by weight based on the residual soil , preferably
0.1 to 0.5% by weight .

The method of adding the improver of the present invention is not particularly limited, but is preferably a method in which a water-soluble polymer is added and mixed, and then the hydraulic cement and quick lime and / or lime are added. There is no problem even if you mix them and use them. In addition, mixing with soil is carried out by a usual method, for example, a method in which an improving agent is sprayed on hydrous soil on a belt conveyor and mixed with a backhoe.

Hydraulic cement, quicklime and masonry are:
Both are usually added as powders, but the water-soluble polymer may be added as an aqueous solution in addition to the powder.

[0021]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Examples 1 to 3 and Comparative Examples 1 to 8 An improvement test was performed using a Kanto loam layer having a water content of 80%, which is difficult to treat in hydrous soil, as a raw material soil.

Each of the raw material soils was subdivided into polyethylene bags of 7 kg each and subjected to an improvement treatment. In the improvement treatment, 210 g (3% based on soil), 420 g (6%), and 630 g (9%) of Portland cement powder were mixed in each bag, and then 210 g (3% based on soil) was further added. The quicklime powder was added and stirred. Further, the container was immediately sealed so as not to splash water.

After the sealed curing for 6 days, JIS A1210
According to (Soil compaction test method by compaction), the improved soil is divided into three layers in a mold with an inner diameter of 15 cm.
The ramming test was performed by ramming 92 times with a 4.5 kg rammer. Next, in accordance with JIS A1211 (CBR test method), a water immersion expansion test was prepared, and the immersion was immersed in a water tank for 4 days to track the expansion amount. Furthermore, after taking out from the water tank and removing water, and performing a predetermined measurement after 15 minutes,
CBR (California Bearing Rat)
io) Load-penetration curve was determined by a tester.

A load at a penetration amount of 2.5 mm (hereinafter referred to as "penetration strength") is read, and CBR is calculated by the following equation. The standard load in the formula is 2.5m as defined by JIS
A standard load at the time of m penetration, 1,370 Kg, was used. CBR
The larger the value, the higher the strength. CBR = (penetration strength / standard load) × 100% Further, the condition of the improved soil was visually observed. Table 1 shows the results of the above test.

Further, the expansion ratios obtained from the expansion amounts measured 4 days after water immersion, which were simultaneously measured, were all good at 1% or less.
In Examples 1 to 3 , a copolymer (intrinsic viscosity [η] = 23.2) having a molar ratio of acrylamide: sodium acrylate = 80: 20 was used as a water-soluble polymer in an amount of 0.1 to soil. It is the case where weight% is added.

Comparative Example 1 is a test result of a raw soil, which was crushed by hand because it was a soft clay and was not applied to a crushing tester. Comparative Example 2 is a treatment with quicklime alone, and Comparative Examples 3 to 5 and 6 to 8 are cases in which quicklime or hydraulic cement is used in combination with the above water-soluble polymer.

[0027]

[Table 1]

Examples 4 to 7 and Comparative Examples 9 and 10 Tests were conducted in the same manner as in Example 1 except that anhydrous lime powder was used instead of quicklime. Table 2 shows the results. Comparative Examples 9 and 10 both use anhydrous stone and water-soluble polymer in combination. The water-soluble polymer is a 30 mol% partial hydrolyzate of polyacrylamide (intrinsic viscosity [η] = 19.5).

[0029]

[Table 2]

[0030]

According to the present invention, the construction waste soil having a high water content, which has been conventionally difficult to use and has been subject to illegal dumping, can be improved in a plant without drying it in the sun by using the water improving soil improving agent of the present invention. And can be reused as a resource as it is for backfilling. In this way, we prevent illegal destruction of construction surplus soil and environmental destruction by collecting sand for backfill,
It greatly contributes to the local community.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ identification code FI // C09K 103: 00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09K 17/06 C09K 17/10 C09K 17 / 22 C09K 17/44 C09K 17/48

Claims (5)

(57) [Claims] 1. An improvement agent for construction residual soil, comprising (A) a hydraulic cement and (B) stone masonry, wherein the weight ratio (B) / (A) is 0.1 to 20. 2. A composition comprising (A) a hydraulic cement, (B) quicklime, and (C) a water-soluble polymer, and (B) in weight ratio.
/ (A) 0.1 to 20 and a water-soluble polymer is 0.1 to 20% by weight of the total soil improving agent. 3. A hydraulic cement comprising (A) a hydraulic cement, (B) limestone, and (C) a water-soluble polymer, and (B) in weight ratio.
/ (A) 0.1 to 20 and a water-soluble polymer is 0.1 to 20% by weight of the total soil improving agent. 4. A water-soluble polymer, in the monomer composition, modifiers construction surplus soil according to claim 2 or 3 monomers containing 1 to 80 mol% having a carboxyl group. 5. The modifier of construction surplus soil according to any one of 4 to claims 1, which is used for water content of from 40 to 200% of the water-containing soil.