JP6809820B2 - Weed control material and how to use it - Google Patents

Description

The present invention relates to a weed control material that suppresses the growth of weeds such as river banks, ridges of fields, or slopes of embankments such as railways and roads, and methods of using the same.

Weeds flourished on the slopes of embankments such as river banks, railroads, and roads, and on the ridges of fields, requiring frequent mowing and spraying of herbicides. Since cutting the grass requires a great deal of labor, a method of spraying a herbicide is generally used.
However, spraying herbicides only kills the grass and needs to be sprayed frequently, which is not a drastic measure. In addition, a method of sprinkling a weed-proof material containing Portland cement and sprinkling water to cover the ground has also been proposed, but it takes time to harden, and it cannot be constructed if it is exposed to rain, etc. There was a problem that flowed. Furthermore, there was a problem that initial frost damage and shrinkage cracks occurred.

Further, a herb control material and a method thereof have been proposed in which a magnesium oxide-based solidifying material containing no Portland cement is sprayed or mixed with soil and watered to solidify and suppress weeds. (Patent Documents 1, 2, and 3)
In Patent Document 1, a weed growth inhibitor containing magnesium oxide and blast furnace slag as main components is mixed with soil on the ground surface, compacted, compacted, and sprinkled on top of the soil. Since the expression is low, it is likely to be washed away by rainfall after construction, and the effect of controlling weeds during the breeding season is likely to decrease.
Since Patent Documents 2 and 3 are magnesium oxide-based solidifying materials similar to Patent Document 1, the initial strength development is low, and the effect of controlling weeds during the breeding season tends to be reduced. Furthermore, the problem with these magnesium oxide-based weed control materials in general is that they may not be able to reach a certain thickness due to watering during construction or being washed away during rainfall on slopes with steep slopes due to the long curing time. It may not cure in some places. In addition, since the initial strength expression is low, plants such as horsetail, phragmites, bamboo grass, and Imperata cylindrica, which have high penetrating power, easily penetrate and thrive.
Patent Document 4 is characterized in that aggregates of incineration ash, slag, and coal ash are spread over the aggregate, and a chloroprene-based latex, an ethylene-vinyl acetate copolymer system emulsion, and an acrylic emulsion solidifying material are sprayed and fixed thereto. It is a weed control method that does not use cement or basic substances, so it is an environmentally friendly weed control material.
However, it takes a lot of labor because it is necessary to spread it to a thickness of 3 to 20 cm by human power or heavy machinery and evenly spray the latex or emulsion on it.

Japanese Unexamined Patent Publication No. 2003-47388 JP-A-2007-330114 Japanese Unexamined Patent Publication No. 2014-51849 Japanese Unexamined Patent Publication No. 2014-234655

The present invention provides a weed control material having a short curing time, high initial strength development, reducing the labor of mowing, ensuring sustainability of weed control and environmental protection, and a method of using the same.

That is, the present invention comprises (1) a herbicide containing magnesium oxide, calcium aluminate and soil, (2) a weed control material containing gypsum, and (3) calcium aluminum. titanate is weed materials CaO / _Al 2 _{O 3} molar ratio 1.0 to 3.0, impurity is not more than 15 wt% (1) or (2), (4) Furthermore, magnesium chloride and / or sulfate One of the weed control materials (1) to (3) containing magnesium, and any of the weed control materials (5) (1) to (4) are spread on the ground and covered with water. The method of using the weed-proof material to be used, and the method of using the herb-proof material in which any one of (6), (1) to (4) is kneaded with water and spread or sprayed on the ground to cover the grass.

Since the weed control material of the present invention has a short curing time and high initial strength development, the use of the weed control material can reduce the labor of mowing, ensure the sustainability of weed control and environmental conservation, etc. Play the effect of.

Hereinafter, the present invention will be described in detail.

The magnesium oxide used in the present invention is not particularly limited, and can be obtained, for example, by calcining a solid containing a magnesium salt such as magnesium carbonate or magnesium hydroxide as a main component at 350 ° C to 1300 ° C. Can be done. It is also obtained by firing or electromelting a magnesium-containing raw material such as naturally occurring brucite or magnesite. It is obtained by calcining or electromelting magnesium hydroxide precipitated by adding an alkaline raw material such as slaked lime to an aqueous solution containing magnesium such as seawater. Further, it is also possible to use a dolomite clinker obtained by heat-treating dolomite composed of magnesium and calcium. When light-baked magnesia is used, the amount of impurities is preferably 15% by mass or less from the viewpoint of initial strength development, and more preferably 10% by mass or less. These are easily available because they are widely distributed as industrial products.

Blaine specific surface area of the magnesium oxide used in the present invention is preferably ^{2000~20000cm 2 / g, 3000~15000cm 2 /} g is more preferable. If it is less than 2000 cm ² / g, it takes time to complete the construction because the reactivity is insufficient. If it exceeds 20000 cm ² / g, the stiffness after adding water is so strong that the working time cannot be secured.

The calcium aluminate used in the present invention contains CaO and Al ₂ O ₃ as main components, which are obtained by mixing a calcia raw material and an alumina raw material and firing them in a kiln or melting and cooling them in an electric furnace. It is a general term for substances having hydration activity, and is a material that has both crystalline and amorphous properties, but has a fast curing time and high initial strength development.
Alumina cement is a typical example of calcium aluminate, and commercially available ones can be used. For example, alumina cement No. 1 and alumina cement No. 2 can be used.
Amorphous calcium aluminate, which cures in a shorter time than alumina cement and has high initial strength development afterwards, is preferably amorphous calcium aluminate that has been rapidly cooled after melting, and the molar ratio of CaO to Al ₂ O ₃ (CaO / Al ₂ O). _{The 3} molar ratio) is preferably 1.0 to 3.0, more preferably 1.7 to 2.5. If CaO / Al ₂ O ₃ molar ratio of 1.0 to 1.7, it is possible to increase the initial strength development was further shortened curing time by formulating a cement and hydrated lime and quicklime.
Further, in the present invention, impurities other than CaO and Al ₂ O ₃ contained in calcium aluminate are preferably 15% by mass or less from the viewpoint of initial strength development, and further preferably 10% by mass or less. .. If it exceeds 15% by mass, it takes time to cure, and it may not harden at a low temperature. Silicon oxide is a typical example of impurities, and other alkali metal oxides, alkaline earth metal oxides, titanium oxide, iron oxide, alkali metal halides, alkaline earth metal halides, alkali metal sulfates, and alkaline soil. Although there is one kind metal sulfate or the like is replaced with a portion of CaO and Al ₂ O _3, not limited in particular.

The vitrification rate of calcium aluminate is preferably 70% or more, more preferably 90% or more in terms of reaction activity. If it is 70% or less, the initial strength development may decrease. The vitrification rate of calcium aluminate is preferably 70% or more, more preferably 90% or more in terms of reaction activity. For the vitrification rate, the main peak area S of the crystalline mineral is measured in advance by powder X-ray diffraction method for the sample before heating, then heated at 1000 ° C. for 2 hours, and then slowly cooled at a cooling rate of 1 to 10 ° C./min. , The main peak area S0 of the crystalline mineral after heating by the powder X-ray diffraction method is obtained, and further, the vitrification rate χ is calculated by using the following formulas using the values of S0 and S.
Vitrification rate χ (%) = 100 × (1-S / S0)
The particle size of the calcium aluminate, in terms of initial strength development is preferably more than Blaine specific surface area ^{3000cm 2 / g, 5000cm 2 /} g or more is more preferable. If it is less than 3000 cm ² / g, the curing time may become long and the initial strength development may decrease.
The amount of calcium aluminate used is preferably 5 to 95 parts by mass with respect to 100 parts by mass in total of magnesium oxide and calcium aluminate. If it is less than 5 parts by mass, early curing may not be obtained. If it exceeds 95 parts by mass, the working time cannot be obtained, and the iron finishing may not be possible or the compaction may not be possible.

As the gypsum used in the present invention, dihydrate gypsum, hemihydrate gypsum and anhydrous gypsum can be used, anhydrous gypsum is preferable in terms of strength development, and fluoroacid by-product anhydrous gypsum and natural anhydrous gypsum can be used. The pH when the gypsum is immersed in water is preferably weakly alkaline to acidic with a pH of 8 or less. When the pH is high, the solubility of the gypsum component becomes high, which may inhibit the initial strength development. The pH referred to here is the pH of a diluted slurry of gypsum / ion-exchanged water = 1 g / 100 g at 20 ° C. measured using an ion-exchange electrode or the like.
The particle size of the gypsum, preferably 3000 cm ² / g or more in Blaine specific surface area value, from the viewpoint of the 5000 cm ² / g or higher initial strength development, the proper work time is obtained.
The amount of gypsum used is preferably 50 to 200 parts by mass with respect to 100 parts by mass of calcium aluminate. If it is less than 50 parts by mass, the working time may not be obtained and the strength development may be lowered. If it exceeds 200 parts by mass, sufficient working time can be taken, but the initial strength may not be obtained.

Conventionally, magnesia cement has been known, which cures by mixing magnesium oxide with magnesium chloride or magnesium sulfate to generate magnesium oxychloride. The type of magnesia cement used is not particularly limited, and conventionally known magnesia cement itself can be used.

The amount of magnesium chloride or magnesium sulfate used is preferably 1100 to 2400 parts by mass of magnesium chloride and 1500 to 3000 parts by mass of magnesium sulfate with respect to 100 parts by mass of magnesium oxide. When both are used in combination, magnesium sulfate is 590 to 1000 parts by mass and magnesium chloride is 750 to 1200 parts by mass. Within this range, the kneaded product has a large decrease in fluidity within 1 hour after kneading, and its shape is maintained.

The amount of the soil used in the present invention is not particularly limited, but is usually preferably 100 to 1000 parts by mass, more preferably 200 to 600 parts by mass, based on 100 parts by mass of the weed control material excluding the soil. When the soil is lower than 100 parts by mass, the strength development is high, but it is economically unfavorable. If it is higher than 1000 parts by mass, the strength is low and there is a possibility of denting.

The soil used in the present invention contains any one or more of gravel, sand, gravel, and clay, and is not particularly limited. Sandy soil such as mountain sand, river sand, and sea sand, silt soil, clay soil, residual soil generated from construction, lightweight aggregate, and recycled aggregate can all be used. In general, decomposed granite soil and dry sand, which are natural soils, have stable quality and are more preferable.

The blending amount of water is preferably 15 to 100 parts by mass with respect to a total of 100 parts by mass of the weed control material of the present invention. If it is less than 15 parts by mass, uniform mixing may be difficult, and if it exceeds 100 parts by mass, strength may not be obtained.

In the present invention, it is possible to use a coagulation modifier. The coagulation adjuster is not particularly limited as long as it promotes or delays the coagulation of cement. Specifically, one or more of alkali hydroxide, alkali metal chloride salt, alkali metal carbonate, oxycarboxylic acid or a salt thereof, phosphoric acid or a salt thereof, dextrin, sucrose, etc. Can be used within a range that does not substantially inhibit.

In the present invention, bulking materials such as wood chips and rice husks, various Portland cements, calcium hydroxide, calcium chloride, limestone fine powder, fly ash, kaolin, silas, diatomaceous earth, silica fumes and other admixtures, and defoaming agents. , Thickener, rust preventive, antifreeze, polymer, clay mineral such as bentonite, anion exchanger such as hydrotalcite, colorant, etc., one or more, which does not substantially impair the object of the present invention. It can be used in a range.

In the present invention, the mixing method of each material is not particularly limited, and each material may be mixed at the time of construction, or a part or all of them may be mixed in advance. It is preferable in terms of quality to mix with water and mix with water in the field.

As the mixing device, any existing device can be used, and for example, a tilting mixer, an omni mixer, a Henschel mixer, a V-type mixer, a nauta mixer, and the like can be used.

The present invention is a method in which weeds on the ground are mowed to about 1 cm or less with a mower or the like, the mowed weeds are removed, and then a weed-proof material is spread and sprinkled with water to cover the weeds. In addition, there is a method of spraying a mixed herbicide to cover the grass, and it is more preferable to mow the grass and then spray the herbicide before covering.

When the weed-proof material is spread on the mowed ground and sprinkled on it to solidify and cover the surface, it is preferable to spread the weed-proof material on the ground and sprinkle water on it with a watering can or the like. The thickness to be spread is not particularly limited, and a thickness of 1 to 3 cm is preferable at the convex portion of the ground. If it is 1 cm or less, it becomes difficult to cover the entire surface, so that the weed control effect may be low. If it is 3 cm or more, the weed control effect is high, but the material cost is high, which is not preferable because a great deal of labor is required.

When spraying the kneaded weed control material onto the mowed ground to solidify and cover the surface, use a continuous kneading mixer that continuously supplies water to the weed control material to pump the kneaded weed control material. However, a method of inserting compressed air at the tip and blowing it is preferable in terms of workability. If the slope is inclined, a plasticizer or a liquid quick-setting agent may be added at the tip. The amount of water used for kneading is preferably 170 to 230 mm in terms of flow value (JISR5201-1998 compliant) so that fluidity that can be pumped can be obtained.

The pump for pumping the mixed herbicide is not particularly limited, and for example, a pump such as a piston type pump, a squeeze type pump, or a snake type pump can be used. Among these, for example, a continuous kneading pumping device that kneads the supplied weed control material with water press-fitted by the blade at the tip of the mixer and continuously pumps it with a snake-type pump connected to it. The method of kneading and pumping is preferable in terms of workability.

The weed-proof material that has been kneaded and pumped can be sprayed by inserting compressed air with a spray nozzle at the tip. Further, on a slope with a strong slope, there is also a method of mixing compressed air with a liquid plasticizer or an acidic liquid quick-setting agent and spraying the compressed air. The addition method is not particularly limited, but there is a method of adding to the mortar using a showering tube or a Y-shaped tube. The thickness to be sprayed is not particularly limited, and a thickness of 1 to 3 cm is preferable at the convex portion of the ground. If it is 1 cm or less, it becomes difficult to uniformly cover it, so that the weed control effect may be low. If it is 3 cm or more, the weed control effect is high, but it is economically unfavorable.

From the viewpoint of ensuring workability, the curing time of the weed control material is preferably 10 minutes or more. Further, when the strength of ² N / mm ² or more is not secured or when the curing speed is slow, a sufficient weed control effect cannot be obtained. In addition, it is necessary to run out the weed control material due to rain and wind, and to provide a curing period.

Hereinafter, description will be given based on an experimental example of the present invention.

"Experimental Example 1"
As shown in Table 1, to a total of 100 parts by mass in which the ratio of magnesium oxide and calcium aluminate was changed, 0 to 100 parts by mass of gypsum, 0.5 parts by mass of a coagulation adjuster, and 600 parts by mass of soil were added. Weed control material was prepared. After laying this weed-proof material on a mold, 20 parts by mass of water was sprinkled on 100 parts by mass of the spread weed-proof material to prepare a test body. Then, the curing time and the compressive strength were measured. The results are also shown in Table 1.
For comparison, a mortar using ordinary cement was prepared. As for the composition of the mortar, the mortar described in JIS R 5201 was prepared in which the ratio of water cement was 50% by mass and the ratio of standard sand manufactured by Cement Association and ordinary Portland cement was 3/4.

<Material used>
Calcium aluminate: CaO / Al ₂ O ₃ molar ratio of calcium carbonate and aluminum oxide was 2.2, silica was added in 3% by mass, melted at 1650 ° C. and rapidly cooled, vitrification rate 97%, brain specific surface area 5000 cm. ² / g
Portland cement: Blast furnace type B cement, brain specific surface area 3750 cm ² / g
Gypsum: Natural anhydrous gypsum, brain specific surface area 5000 cm ² / g
Soil: Dried river sand from Niigata prefecture, 1.2 mm under-sieving alumina cement: Alumina cement No. 1, Denka's coagulation adjuster: Anhydrous sodium citrate, Iwata Chemical Industry Co., Ltd. Water: Tap water Ordinary cement: Ordinary Portland cement, Commercially available sand: Standard sand manufactured by Cement Association Magnesium oxide: Magnesium oxide produced in China is calcined to prepare a brain specific surface area of 4000 cm ² / g.

<Measurement method>
Curing time: The time during which the kneaded weed control material was not dented even when pressed with a finger was measured.
Compression strength: The uniaxial compression strength conforms to the uniaxial compression test method (Pavement Test Method Handbook, Japan Road Association) of a stable treatment mixture in an environment of 20 ° C and 60% relative humidity, and the specimen dimensions are 100 mm in diameter and 127 mm in height. The test piece was made into a columnar shape, packed in three layers, and each layer was pierced 25 times. The strength of the material was measured at 6 hours and 28 days, and the curing method was air-dry curing in an environment of 20 ° C. and 60% relative humidity.

From Table 1, it can be seen that the herbicide of the present invention has a short curing time and a high initial strength development.

"Experimental Example 2"
A weed control material was prepared by adding 20 parts by mass of gypsum, 0.5 parts by mass of a coagulation adjuster, and 600 parts by mass of soil to a total of 100 parts by mass of 60 parts by mass of magnesium oxide and 40 parts by mass of calcium aluminate. After laying this weed-proof material on a mold, 20 parts by mass of water was sprinkled on 100 parts by mass of the spread weed-proof material to prepare a test body. Then, the curing time and the compressive strength were measured. Then, the curing time, compressive strength, and static elastic modulus were measured. The results are also shown in Table 2.
For comparison, a mortar using ordinary cement was prepared. As for the composition of the mortar, the mortar described in JIS R 5201 was prepared with a water-cement ratio of 50% by mass and a ratio of standard sand manufactured by Cement Association and ordinary Portland cement to 3/1.

<Material used>
Calcium aluminate: CaO / Al ₂ O ₃ molar ratio of calcium carbonate and aluminum oxide was changed, 3% by mass of silica was added, melted at 1650 ° C. and rapidly cooled, vitrification rate 97%, brain specific surface area 5000 cm ² / G
Portland cement: Blast furnace type B cement, brain specific surface area 3750 cm ² / g
Gypsum: Natural anhydrous gypsum, brain specific surface area 5000 cm ² / g
Soil: Dried river sand from Niigata prefecture, 1.2 mm under-sieving alumina cement: Alumina cement No. 1, Denka's coagulation adjuster: Anhydrous sodium citrate, Iwata Chemical Industry Co., Ltd. Water: Tap water Ordinary cement: Ordinary Portland cement, Commercially available sand: Standard sand manufactured by Cement Association Magnesium oxide: Magnesium oxide produced in China is calcined to prepare a brain specific surface area of 4000 cm ² / g.

From Table 2, it can be seen that the herbicide of the present invention has a short curing time and a high initial strength development.

"Experimental Example 3"
To a total of 100 parts by mass of 30 parts by mass of magnesium oxide and 70 parts by mass of calcium aluminate, 330 parts by mass of magnesium chloride or 450 parts by mass of magnesium sulfate was added, 20 parts by mass of plaster, and 0.5 parts by mass of coagulation adjuster. A weed control material was prepared by adding 600 parts by mass of parts and soil. After laying this weed-proof material on a mold, 20 parts by mass of water was sprinkled on 100 parts by mass of the spread weed-proof material to prepare a test body. After that, the curing time and the compressive strength were measured. The results are also shown in Table 3.

From Table 3, it can be seen that the herbicide of the present invention has a short curing time and a high initial strength development.

"Experimental Example 4"
For each of the weed control materials of Experiment No. 1-4, 1-8, 1-16 of Experimental Example 1 and Experiment No. 3-1 of Experimental Example 3, weed control materials (magnesium oxide, calcium aluminate, anhydrous gypsum) , Coagulation adjuster, soil), 20 parts by mass was added to the omnimixer instead of watering, and the mixture was laid on the mold or foundation surface in the same manner as in Experimental Example 1. Tested.

<Material used>
Calcium aluminate: CaO / Al ₂ O ₃ molar ratio 2.2, vitrification rate 97%, brain specific surface area 5000 cm ² / g

From Table 4, it can be seen that the herbicide of the present invention has a short curing time and a high initial strength development.

The weed-proofing material of the present invention and the method of using the weed-proofing material have effects such as reducing the labor of mowing and ensuring the sustainability of weed-proofing. Therefore, on river banks, ridges of fields, railways, roads, etc. It is widely used in the civil engineering field because it can suppress the growth of weeds such as the slope of the embankment.

Claims (6)

A herbicide containing magnesium oxide, calcium aluminate and soil .
The amount of calcium aluminate is 5 to 95 parts by mass with respect to 100 parts by mass of magnesium oxide and calcium aluminate in total.
A herbicide whose amount of soil is 100 to 1000 parts by mass with respect to 100 parts by mass of the herbicide excluding soil . The weed control material according to claim 1, further comprising gypsum in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of calcium aluminate . Calcium aluminate, CaO / Al ₂ O ₃ molar ratio 1.0 to 3.0, weed material according to claim 1 or 2 impurities is not more than 15 wt%. The herbicide according to any one of claims 1 to 3, further comprising magnesium chloride and / or magnesium sulfate. A method for using a weed-proof material, which comprises laying the weed-proof material according to any one of claims 1 to 4 on the ground and sprinkling water on the ground to cover the weed-proof material. A method for using a weed-proof material, which comprises mixing the weed-proof material according to any one of claims 1 to 4 with water and laying or spraying it on the ground to cover it.