JP2014176847A - Manufacturing method of foam hydrothermally-solidified body using incineration ash as main raw material and foam hydrothermally-solidified body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive manufacturing method of a foam hydrothermally-solidified body having even water permeability together with strength and aggregate performance, and also using incineration ash as a main raw material, and the foam hydrothermally-solidified body manufactured by the manufacturing method.SOLUTION: The manufacturing method of a foam hydrothermally-solidified body of the present invention, includes the following processes (a)-(c): (a) a mixing process of mixing by adding cement by 5-25 mass% to 100 mass% of incineration ash including amphoteric metal, (b) a kneading process of providing a kneaded object of a funicular state by hydrating calcium oxide included in the incineration ash and the cement by inputting kneading water into a mixture of the incineration ash and the cement and kneading the mixture after the mixing process, and (c) a curing process of providing the foam hydrothermally-solidified body by generating and foaming gas by reacting the amphoteric metal included in the incineration ash and alkaline water after transferring the kneaded object of the mixture of the incineration ash and the cement and the kneading water to a molding form and hydrothermally solidifying it while adding predetermined compressive force following the kneading process.

Description

  The present invention is a foam hydrothermal solidified production method and foam hydrothermal solidified material mainly using incinerated ash, which has water permeability with a certain strength and aggregate performance, and is used as a material for civil engineering and construction. The present invention relates to a foamed hydrothermal solidified product that can be produced, and a foamed hydrothermal solidified product produced by the production method.

  Currently, in the era when industrial products such as paper, electrical products, processed foods are produced and consumed in large quantities, factories, shops, general households, etc. Municipal waste (hereinafter collectively referred to as “waste”) is discharged.

  These wastes include, for example, paper sludge from factories, plastics, etc., and municipal wastes include scraps from stores, cardboard, wood scraps, garbage such as vegetable scraps from general households, and discarded newspapers. And magazines are included. Various types of sludge and incinerated ash produced by processing these wastes are also diverse.

  Among these wastes, those that do not elute harmful chemical substances are disposed in landfills as they are or after being incinerated into ash. Also, for example, incineration ash obtained by incinerating paper sludge with plastic solid fuel, tire chips, wood chips, coal, etc. contains heavy metal hazardous chemicals such as cadmium, lead, hexavalent chromium, arsenic, mercury, and selenium. Since they can be dissolved if they are buried in the ground as they are, they cannot be directly landfilled.

  For this purpose, incinerated ash containing harmful chemical substances of these heavy metals is disposed of in landfills after processing such as cement raw materials, or melt solidification, chemical (chelating agent) processing, solvent extraction, and the like. However, among these treatment methods, the chemical treatment method requires several percent of expensive chelating agent for the incinerated ash to be treated, and the melt-solidification treatment method requires high equipment costs and a large amount of energy. It becomes. Therefore, in these treatment methods, waste disposal costs increase, the profitability becomes economically low, and this is a problem in adoption.

  On the other hand, even in landfill disposal or use as a raw material for cement, in recent years it is in a difficult situation / environment. In other words, it is essential to secure the landfill site for landfill disposal, but the selection and securing of this landfill site has become extremely difficult year by year. Even in rural areas, it is difficult to find.

  Even in the use of cement raw materials, public works decreased due to recent financial difficulties, etc., and as a result, demand for cement has reached its peak, and it is not possible to expect further expansion of use in the future. However, even in such a situation / environment, a great variety of waste is discharged every day.

  For this reason, development of processing technology that can dispose of these wastes other than landfill, and these wastes include those that can be recycled after being recycled (recycled). Recycling technology is being developed in order to build a recycling-oriented society that can make effective use of waste. As this regeneration technology, conventional hydration solidification reaction (hydrothermal solidification reaction) prevents elution of harmful chemicals from incineration ash, and hydrothermal solidification that can be regenerated into materials such as roadbed materials and land improvement materials. Technology has been developed.

  For example, in Patent Document 1 below, by suppressing expansion when producing a solidified body from incinerated fly ash, a high-quality solidified body that is stable in the long term and has no strength reduction or collapse can be obtained. For the purpose of providing a method for producing a waste incineration fly ash solidified body, at least one of water and hot water is added to the incineration fly ash generated when the waste is incinerated. After kneading for 120 minutes, oxidation of amphoteric metals such as aluminum contained in incineration fly ash and reaction of expansive compounds, and then adding at least one of an alkali agent and a substance containing silica or alumina as an additive The invention of a method for producing a solidified body by using a hydrothermal solidification reaction is described.

  In addition, Patent Document 2 listed below has high moisture absorption and water retention, which does not impair the porosity and porosity that are the original properties of paper sludge incineration ash, and suppresses the elution of harmful components of heavy metals. Water and / or hot water, quick lime, and coal ash for incineration ash generated when paper sludge is incinerated for the purpose of providing a method for producing a granular solidified material suitable for soil improvement materials and frost heave suppression materials And after curing the molded body granulated into a granule by mixing at a temperature from room temperature to 98 ° C., then, the solidified body is produced using a hydrothermal solidification reaction. The invention of the manufacturing method of the paper sludge incineration ash water heat solidification body which has a heat resistant structure is described.

  On the other hand, during road maintenance, residential land development, etc., “banking” is generally performed in which earth and sand are raised and raised to form a flat surface. However, if the ground at the construction site is so-called soft ground with a high water content, the soil volume gradually decreases due to the drainage of the pore water contained in the ground due to the embankment material and the weight of the building. "Consolidation (phenomenon)" occurs, and as a result, the ground sinks. (Hereinafter, pore water drained by consolidation is called “consolidated water”, and ground subsidence caused by consolidation is called “consolidation subsidence.”)

  If embankment is performed easily on soft ground, the compacted water will be drained gradually through the ground around the embankment, resulting in road subsidence or uneven settlement during or after maintenance. There is a risk of adverse effects such as the inclination of the building and the uplift of the land around the construction site. In addition, since the consolidation is also promoted by the weight of the heavy equipment for construction, there is a possibility that a problem may occur in the trafficability of the heavy equipment for construction and the transportation truck on the soft ground.

  For this reason, when embankment is performed on soft ground, various ground improvement works are carried out in order to suppress the above-described adverse effects and to ensure trafficability.

  As an example of ground improvement work, the “horizontal drain method” is known, in which drain material with a water conveyance and drainage function is spread on the soil to be embanked. A construction method for forming a sand layer (sand mat) is referred to as a “sand mat (laying sand layer) construction method”.

  In the horizontal drain construction method, the consolidated water is sucked up from the foundation ground under the drain material to the drain material by the water introduction / drainage function of the drain material, so that the consolidated water can be discharged efficiently and stably.

  In the sand mat method, a sand layer (sand mat) having a thickness of about 1 meter is formed on the foundation ground. Since sand has high water permeability, the sand mat formed on the soft ground can suck up the consolidated water and functions as a horizontal drain. Furthermore, since sand has a high supporting force, it is possible to prevent the heavy machinery that performs the work from falling or sinking.

  Therefore, by forming the sand mat on the soft ground and then embanking, the compacted water is discharged in a stable and efficient state, so that the adverse effects described above can be suppressed, and the sand itself has high Supporting force can prevent accidents caused by heavy machinery falling or sinking.

  Further, as a drain material other than sand, fiber drains mainly composed of plant fibers as described in Patent Document 3 and Patent Document 4 below are known.

  In this way, when embankment on soft ground, in order to drain the consolidated water efficiently and stably, horizontal drains in which various drain materials such as sand are laminated on the foundation ground in advance before embankment The construction method is generally performed, and among them, the sand mat method is often adopted.

JP 2000-308867 A JP 2010-173912 A Actual fairness 6-34413 JP-A-11-172666

  However, the drain sand that can be used as a sand mat is naturally derived sand, so that it can cause natural destruction to the extent that it is widely used.Since the sand resources themselves are limited, high-quality drain sand Cost increase is a problem.

  Even if sand is not used as the drain material, the cost of the drain material itself remains unchanged. In addition, as long as the horizontal drain method is adopted, a process of constructing the drain material is absolutely necessary (in the case of a pull-out type drain material, an additional pulling process is required), and the drainage capacity of the drain material used is compact. Since the traveling speed depends, depending on the drainage performance of the drain material, it takes time to increase the density of the soft ground, which may result in a longer construction period.

  Since the above-mentioned problems occur because the above-mentioned problem is caused by using a drain material for ground improvement, the embankment itself is provided with a function of draining compacted water, that is, a fill material that can also function as a drain material. Based on the idea of developing, various studies were made on the required performance of the embankment material that has basic performance (uniaxial compressive strength, aggregate performance such as CBR value) as a embankment material and also has a drainage function of consolidated water. It was.

  On the other hand, the present inventors are investigating a method for reusing incinerated ash using a hydrothermal solidification reaction in order to promote the reuse of waste in parallel with the study on embankment. The invention of the method for producing the waste incineration fly ash solidified body described in 1 and the invention of the method for producing the paper sludge incinerated ash hydrothermally solidified body described in Patent Document 2 are incinerated ash while maintaining a temperature of around 95 ° C. Since the target hydrothermal solidified product cannot be obtained without kneading the raw material containing the material, equipment for maintaining a high temperature such as an autoclave is indispensable for actually carrying out the invention, and the equipment cost and energy consumption In addition, in the invention of the method for producing a paper sludge incinerated ash hydrothermally solidified body described in Patent Document 2 described above, a granulation step for forming a raw material kneaded product into a molded body is necessary. Installation for granulation process Since it is necessary, that there is a problem that further requires equipment costs, and finding the.

  Therefore, the present inventors have repeatedly studied a low-cost method for obtaining a hydrothermal solidified body of incinerated ash, and the incinerated ash is hydrothermally produced under specific conditions that do not require expensive equipment such as an autoclave. It was found that a foamed hydrothermal solidified body having a surface cell ratio and a specific surface area within a specific range can be obtained by solidification.

  Furthermore, the present inventors are required to have a certain strength and water permeability by controlling the surface cell ratio and specific surface area of the foamed hydrothermal solidified body, since the obtained foamed hydrothermal solidified body has water permeability. The present invention has been found to be suitable for use as a material to be completed, and the present invention has been completed.

  That is, the present invention provides a new means for reusing incinerated ash, and as an application example, it can be suitably used as embankment material or weed control material, and has water permeability as well as strength and aggregate performance. It is an object of the present invention to provide a foamed hydrothermal solidified body made of incinerated ash as a main raw material and a foamed hydrothermal solidified body manufactured by the manufacturing method.

In order to solve the above-mentioned subject, the manufacturing method of the foam hydrothermal solidification of the present invention is characterized by including the following processes (a)-(c).
(A) A mixing step of adding 5 to 25% by mass of cement to 100% by mass of incinerated ash containing an amphoteric metal, and mixing them;
(B) After the mixing step, kneaded water is added to the mixture of the incinerated ash and cement to knead to hydrate the quick lime contained in the incinerated ash and cement to obtain a kneaded product in a funicular state. Kneading process,
(C) After the kneading step, the kneaded product of the mixture of the incinerated ash and cement and the kneaded water is transferred to a mold and hydrothermally solidified while applying a predetermined compressive force, and the amphoteric metal contained in the incinerated ash A curing process to obtain a foamed hydrothermal solidified body by reacting with alkaline water to generate gas and foam.

According to the method for producing a foamed hydrothermal solidified body of the present invention, the surface bubble ratio is 0 to 22%, the BET specific surface area is 75 to 110 m ² / g, the water absorption is 40 to 63%, and the uniaxial compression ratio is A foamed hydrothermal solidified body of 5 to 18 N / mm ² can be easily obtained at low cost without using a special mechanical device. The foamed hydrothermal solidified product thus produced can be used as various materials that require moisture-releasing properties, water permeability and strength.

  For example, a foamed hydrothermal solidified body (hereinafter, simply referred to as “foamed hydrothermal solidified body of the present invention”) produced by the production method of the present invention on soft ground having a CBR value of 3% or less is used as a fill material. Then, since the foam hydrothermal solidified body of the present invention has a design CBR value of 70% or more, it sufficiently satisfies the quality standard required for the embankment material and the design CBR value of 20% or more, and is sufficiently used as the embankment material. Is possible.

  In addition, when the foamed hydrothermal solidified body of the present invention is used as a banking material, the water permeability of the foamed hydrothermally solidified body can efficiently absorb and drain the compacted water from the foundation ground. In the case of embankment on the ground, the conventionally used horizontal drain material becomes unnecessary, and the drain material construction process becomes unnecessary, so that not only the drain material cost but also the construction period can be shortened.

  That is, by utilizing the foamed hydrothermal solidified material of the present invention as a banking material, it is possible to realize an epoch-making method in which a horizontal drain material is unnecessary even when banking on soft ground. In addition, since the foaming hydrothermal solidification body of this invention is equipped with a drainage capability as above-mentioned, it can also be utilized as a drain material naturally.

  The foamed hydrothermal solidified body of the present invention can also be used as a material for controlling weeds. That is, since the foamed hydrothermal solidified body of the present invention has a high moisture-releasing property, it quickly releases the absorbed water, so that it is easy to maintain a dry state. Therefore, it is possible to construct an environment that is not suitable for plant vegetation by spreading the foamed hydrothermal solidified body of the present invention on the ground.

The surface bubble ratio in the hydrothermal solidified body of the present invention means a ratio occupied by the area of visible bubbles (voids) in an arbitrary cross section of the solidified body, and an arbitrary cross section (10 mm) of the target solidified body. X10 mm square), the area of bubbles with a visible size is measured with a planimeter to obtain the surface bubble area (mm ² ), and is calculated by the following formula.
Surface bubble rate (%) = (surface bubble area (mm ² ) / 100 (mm ² )) × 100

Further, the water absorption rate in the foam hydrothermal solidified body of the present invention means the percentage of the total amount of water contained in the surface-dried saturated solidified body with respect to the absolute dried solidified body, and the mass in the absolutely dry state It is assumed that (absolute dry mass) and the surface dry saturated water mass (saturated water mass) are measured and calculated by the following formula.
Water absorption rate (%) = ((saturated water mass−absolute mass) / absolute mass) × 100

In the foamed hydrothermal solidified body of the present invention, the balance between strength and water permeability is important. That is, in order to improve water permeability, the surface bubble rate is increased. However, if the surface bubble rate is increased, the strength is lowered. Therefore, the surface bubble rate is preferably 22% or less. In the present invention, a uniaxial compressive strength of 5 N / mm ² or more can be achieved if the surface bubble ratio is 22% or less.

Moreover, in the foam hydrothermal solidified body of the present invention, even if the surface bubble rate is 0%, the bubbles are of such a size that the bubbles are not visible, and actually have a porous structure. It becomes what has water permeability by connecting. However, if the size of the bubbles is too small, the water absorption and water permeability are reduced due to a decrease in the connection between the bubbles, and therefore, the specific surface area is preferably 75 to 110 m ² / g or less. If the specific surface area is 110 m ² / g or less, it is possible to achieve a water absorption of 40% or more even if the surface bubble rate is 0%.

According to the method for producing a foamed hydrothermal solidified body of the present invention, the surface bubble ratio having the above-described effects is 0 to 22%, the BET specific surface area is 75 to 110 m ² / g, and uniaxial compression is performed. A foamed hydrothermal solidified body having a rate of 5 to 18 N / mm ² can be easily obtained at low cost without using a special mechanical device.

  In the method for producing a foamed hydrothermal solidified body of the present invention, as the incineration ash, waste incineration ash such as municipal waste, wood chips / tire chips, paper sludge, sewage sludge, biomass, or coal, solid waste fuel Any of incineration ash such as paper / plastic solidified fuel or a mixture thereof can be used.

  Moreover, in the manufacturing method of the foaming hydrothermal solidification body of this invention, when lime is added and mixed with respect to the said mixture in the mixing process of said (a), content of quick lime (CaO) component in incineration ash is extreme. Even in the case of a small amount, the heat generation of the digestion reaction can be further activated by additionally mixing quicklime.

  In that case, if the addition ratio of lime is too high, the alkalinity of the foamed hydrothermal solidified product becomes strong, so the addition ratio of lime is preferably 40% by mass.

  Moreover, in this invention, if it is about 10 mass% of the said mixture, you may contain the inorganic sludge further with respect to the said mixture.

  In the method for producing a foamed hydrothermally solidified product of the present invention, when a certain amount of water is added to the mixture as mixing water in the mixing step (a), dust generation during mixing is reduced, and quick lime It is preferable to start the digestion reaction and moisten it somewhat so that the kneading in the next kneading step becomes smooth.

  In this case, the addition amount is preferably 15 parts by mass or more with respect to 100 parts by mass of the mixture in order to sufficiently suppress the generation of dust. Moreover, since there exists a possibility that it may granulate when there is too much water for mixing and there exists a possibility that a bad influence may be produced in mixing with cement, it is preferable to make the amount of the water for mixing to add about 25 mass parts an upper limit.

  The total amount of water to be added as mixing water in the mixing step (a) and water to be kneaded in the kneading step (b) is too small. As the viscosity increases, the viscosity of the kneaded material becomes smaller, so that the kneading becomes easier. However, if too much, it takes time to evaporate excess water.

  Therefore, the total amount of water added as mixing water and kneading water is preferably in the range of 35 to 55 parts by mass with respect to 100 parts by mass of the solid component. In addition, there is no restriction | limiting in particular in the temperature of the water to add, There is no problem even if it is about 98 degreeC warm water.

Further, in the method for producing a foamed hydrothermal solidified product of the present invention, when the kneaded product is hydrothermally solidified, gas is generated by reacting alkaline water with amphoteric metals such as metallic aluminum contained in the incinerated ash. Foam and expand. If the kneaded product is solidified in the absence of a molding mold, it will expand greatly, and the resulting foam hydrothermal solid will have a surface foam ratio of over 22% and a uniaxial compressive strength of 5 N / mm ^2. Less than Therefore, in order to suppress the surface bubble ratio to 22% or less and ensure the strength of the solidified body, the kneaded material needs to be solidified in the molding frame so that the expansion can be kept within a certain range by applying a compressive force. is there.

The compression force applied to keep the expansion within a certain range is about 50 kg / cm ^2, but may be appropriately adjusted so that the surface bubble ratio is 22% or less.
The molding mold is not limited as long as it has a strength that resists the force in the expansion direction when the kneaded product is solidified. For example, potholes dug in the ground, earth or stone walls piled up to a predetermined height from the ground surface can be used as the mold.

  When the pit hole dug in the ground is used as a mold, the mold can be obtained by simply digging the ground, so there is no cost, and as a result, it can contribute to the cost reduction of the product. A mold having a shape and shape can be easily obtained.

  Also, if the content of amphoteric metal such as metallic aluminum in incineration ash is too small, there is a risk that hydrogen gas sufficient for foaming may not be generated, while amphoteric metal itself is unrelated to hydrothermal solidification reaction. Therefore, the content of the amphoteric metal in the incineration ash is preferably 0.5% by mass to 10% by mass.

  In addition, according to the method for producing a foamed hydrothermal solidified product of the present invention, in the curing process, the temperature of the kneaded product in the molding mold rises due to the heat of hydration of the lime component, and the hydrothermal solidification reaction proceeds. Solidification is completed within 8 hours. The heat of hydration depends on the amount of the kneaded product, while the exhaust heat from the kneaded product is proportional to the surface area. Therefore, from the viewpoint of keeping the temperature of the kneaded product in the molding mold above a certain level, There are advantages to using it. In the case of a small formwork, it may be necessary to consider the heat retaining property of the formwork in order to suppress exhaust heat.

  In addition, in the method for producing a foamed hydrothermal solidified body of the present invention, when it is desired to obtain a foamed hydrothermal solidified body having a higher strength, an unraveling step of evaporating water of the kneaded material obtained in the kneading step (b) to some extent. Then, the process may proceed to the curing step (c). In the unraveling step, the water may be evaporated until the kneaded product is in the pendular state (slump value 0) from the funicular state (slump value about 5-7). The time required for the unraveling process is approximately 10 to 50 minutes.

When a kneaded product obtained by evaporating water until the slump value becomes 0 is obtained, the foamed hydrothermally solidified product has a bubble size smaller than the visible size and the surface bubble rate becomes 0%. 40%, and the uniaxial compressive strength is about 12 to 18 N / mm ² . On the other hand, when cured using a kneaded material having a slump value of 5 to 7 without passing through the unraveling step, the surface foam ratio of the foamed hydrothermal solidified body is 5 to 30%, and the water absorption is 50%. As described above, the uniaxial compressive strength satisfies 5 N / mm ² or more.

2 is a cross-sectional view of a foamed hydrothermal solidified body showing a method for measuring the surface cell ratio of Example 1. FIG. It is sectional drawing of the foaming hydrothermal solidification body which shows the measuring method of the surface bubble rate of Example 2. FIG.

  Examples of the method for producing a foamed hydrothermal solid according to the present invention will be described below. However, the following examples illustrate a method for producing a foamed hydrothermal solidified body using incinerated ash as a raw material for embodying the technical idea of the present invention, and the present invention is limited to this example. However, the present invention can be equally applied to various modifications without departing from the technical concept shown in the claims.

  For example, in the examples shown below, some processes are made by transferring kneaded materials using heavy machinery, etc., but when these processes are automated by installing machines and devices such as transfer devices It is applicable to.

[Example 1]
[Incineration ash and cement]
The incinerated ash used here is a mixture of plastic solid fuel and tire chips, 50% by mass, wood chips 20% by mass, coal 20% by mass, and paper sludge 10% by mass. Blast furnace cement was used as the cement. The incinerated ash contained about 8% by mass of metallic aluminum.

Papermaking sludge is generally generated when recycled used paper, but here, it also includes what is generated from a pulp manufacturing process, a papermaking manufacturing process, and a used paper processing process.
[Mixing process]
After adding 20 parts by mass of cement to 100 parts by mass of the incineration ash and mixing for 5 minutes, add 20 parts by mass of water as mixing water to the solid component (total amount of incineration ash and cement), The mixture was mixed for 5 minutes so that the cement was uniformly dispersed.

[Kneading process]
To 100 parts by mass of the solid component of the mixture obtained as described above, 25 parts by mass of water was added as kneaded water, and the mixture was kneaded and kneaded to obtain a kneaded product. This kneading was performed for about 30 minutes until the slump value of the kneaded product reached 5. As the kneader, a kneader having a kneading capacity of about 4 m ³ that can be kneaded at a time was used, and 4 k ³ × 10 kneaded products were obtained.

[Curing process]
In the curing process, the kneaded material obtained as described above was sequentially transferred and accumulated in the molding mold using a 40 m ³ capacity pothole previously dug into the molding mold, and then the heavy machinery was Hydrothermal solidification for 3 hours in a state where the applied pressure is about 50 kg / cm ² , and then curing for 5 hours, excluding pressurization by heavy machinery, and then hydrothermal solidification for foaming according to Example 1 Got the body.

[Example 2]
A foamed hydrothermal solidified body according to Example 2 was obtained in the same manner as in Example 1 except that the kneading step in Example 1 was carried out until the slump value was 7.

[Example 3]
The kneaded material obtained in the kneading step of Example 1 was transferred to 10 4m ³ potholes (hereinafter referred to as “unraveling formwork”) previously dug out of the ground, respectively. As in Example 1, except that the process was left for 50 minutes to evaporate water until the slump value became 0, and then the kneaded material was unwound using a heavy machine and transferred and accumulated from the mold to the mold. Similarly, a foamed hydrothermal solidified product according to Example 3 was obtained.

[Comparative Example 1]
The kneaded product obtained in the kneading step of Example 1 was allowed to stand on a flat plate without being placed in a molding frame and solidified hydrothermally to obtain a foamed hydrothermal solidified product according to Comparative Example 1.

[Characteristic evaluation]

  The characteristics of the foamed hydrothermal solid bodies according to Examples 1 to 3 and Comparative Example obtained as described above are summarized in Table 1. Note that Comparative Example 1 could not be effectively measured except for uniaxial compressive strength because it was easily pulverized and the bubbles were too large.

The surface bubble rate was determined by forming a flat cut surface with a cutter and measuring the area of bubbles with a visible size in a square area of 10 mm × 10 mm with a planimeter to obtain the surface bubble area (mm ² ) It was calculated by the calculation formula. (See Figures 1 and 2)
Surface bubble rate (%) = (surface bubble area (mm ² ) / 100 (mm ² )) × 100
In Example 3, since the bubbles were smaller than the visible level, the surface bubble rate was set to zero.

In addition, the water absorption is the absolute dry state of the total water amount contained in the solid body in the surface dry saturated state for each foam hydrothermal solidified body that is crushed so that each side becomes a gravel of about 5 cm. As a percentage with respect to the solidified body, the mass in an absolute dry state (absolute dry mass) and the mass in a surface dry saturated water state (saturated water mass) were measured and calculated by the following calculation formula.
Water absorption rate (%) = ((saturated water mass−absolute mass) / absolute mass) × 100

In addition, for moisture release, the moisture content after 24 hours, which is the mass of the foamed hydrothermally solidified body after being left for 24 hours in an environment of 25 ° C. and 65% humidity, from the surface dry saturated water state, From the difference from the saturated water mass, the mass of the moisture released by being left for 24 hours (24 hour moisture release amount) is obtained, and obtained as a percentage of the water absorption amount (= saturated water mass-absolute dry mass) by the following calculation formula. It was.
Moisture release (%) = (24 hour moisture release / water absorption) x 100

Further, the BET specific surface area measured using the automatic specific surface area measuring device “Gemini 2375” manufactured by Shimadzu Corporation at the Tottori Prefectural Industrial Technology Center was used as the specific surface area.

From Table 1, foamed hydrothermal solidification of Examples 1 to 3 are both in the uniaxial compression strength 5N / mm ² or more 18N / mm ² or less, it can be seen that certain strength is ensured.

In Examples 1 to 3, both have a water absorption rate of 40% or more and a uniaxial compressive strength of 5 N / mm ² or more. It has been shown that the smaller the value is, the higher the water absorption rate is, while the uniaxial compressive strength is reduced. If the surface cell ratio is too large as in Comparative Example 1, it can be seen that both strength and water permeability cannot be achieved. .

  With respect to the upper limit of the surface bubble ratio, from the results of Example 2, if it is 22% or less, the foamed hydrothermal solidified body has sufficient strength to be used for embankment and the like and has both strength and water permeability. Is considered to be obtained.

  Further, it has been shown that the smaller the surface bubble ratio and the larger the specific surface area, the lower the water absorption rate, while improving the uniaxial compressive strength. As shown in the results of Example 3, it can be seen that if the specific surface area is equal to or less than a certain value, water absorption is ensured.

That is, in Example 3 where the surface bubble rate is 0% and the specific surface area is 110 m ² / g, a water absorption rate of 40% is achieved. From the results of Example 3, the surface bubble rate is 0%. Even in this case, if the specific surface area is 110 m ² / g or less, it is considered that a foamed hydrothermal solidified body having both strength and water permeability can be obtained.

On the other hand, the foamed hydrothermal solidified body obtained as Comparative Example 1 is easily pulverized, and as shown in Table 1, the uniaxial compressive strength is 2 N / mm ² or less. Therefore, it is not suitable for use in embankments where a certain level of strength is required.

Therefore, in the present invention, the strength and water permeability are controlled by controlling the specific surface area to be 110 m ² / g or less when the surface bubble ratio is 22% or less and the surface bubble ratio is 0%. It can be seen that a foamed hydrothermal solidified body is obtained.

[Experimental example: embankment on soft ground]
Using the foamed hydrothermal solidified body of Example 1 obtained as described above, embankment was performed on soft ground, and the aggregate performance as an embankment material was evaluated.

Soil target ground CBR: 2.1%
Cone index: 192.7 kN / m ²
Water content: 11.6%
Depth: 30cm

  The above-mentioned soft ground was embanked with a foam hydrothermal solidified body of Example 1 or, as Comparative Example 2, mountain soil as a banking material. The embankment was performed by rolling each embankment material with a 1-ton roller every time 10 cm is spread.

About Trafficability Table 2 shows the measurement results of the cone index after two embankment treatments (that is, the embankment layer is 20 cm).

As shown in Table 2, in Comparative Example 2, the cone index of 700 kN / m ^2, which allows the general bulldozer 21t class to run, was 677 kN / m ^{2 even} when the banking was performed twice. In Comparative Example 2, the cone index was as low as 967 kN / m ² even after four embankments.

On the other hand, in Example 1, and 1212kN / m ² twice embankment, becomes shall exceed 1200kN / m ² that is required for the travel of the dump truck, the embankment material to soft ground, to ensure Torafika Stability It was shown to be an excellent embankment material.

On-site CBR value In Comparative Example 2, even if four embankments were performed, the on-site CBR value was 12.2%, which could not exceed the embankment reference value (CBR value 20.0%). In No. 1, the on-site CBR value was 21.9% and exceeded the embankment reference value after three embankments.
Thus, the foamed hydrothermal solidified body according to the present invention is particularly excellent in the effect of ground improvement (ground reinforcement) for soft ground and does not require a drain material. Therefore, since the strength of the roadbed embankment can be secured with a small number of processes, it is possible to reduce costs and shorten the construction period by using the foamed hydrothermal solidified body according to the present invention as embankment.

  As described above, the excellent effect as the embankment material included in the foam hydrothermal solidified body according to the present invention is realized by the foam hydrothermal solidified body according to the present invention, which is realized by high water absorption and moisture release properties as well as strength. By having water permeability and drainage capacity, it is considered that the compacted water in the soft ground is sucked up and drained.

  Moreover, the foaming hydrothermal solidification body concerning this invention can be utilized as a civil engineering material for weed control. This is because the foamed hydrothermal solidified product according to the present invention is an inorganic material with no nutrients, and also has water permeability and moisture release properties as well as strength. For example, by spreading on the ground, it is possible to suppress the growth of weeds in a desired land such as a flower bed or a median strip. Hereinafter, the “weedproofing / greening method” using the foamed hydrothermal solidified product according to the present invention will be described.

[Formation of weed control base layer]
First, the particle size of the hydrothermal foam body for foaming according to the present invention is adjusted so that the particle diameter is about 20 mm or less. Next, construct the weed suppression base layer on the land of the desired shape and size by spreading the hydrostatic solidified foamed foam on the ground to be weed suppression target and then compacting it to a predetermined hardness Can do.

Since the weed suppression base layer is a close layer formed by compacting a foam hydrothermal solidified body having a strength of 5 N / mm ² or more, even if seeds are rooted on the weed suppression base layer, root establishment Even if seeds germinate under the weed suppression base layer, it is prevented from growing beyond the weed suppression base.

  Moreover, since the foamed hydrothermal solidified material according to the present invention is an inorganic substance without nutrients and has high water permeability and moisture release properties, moisture is not easily stored on the weed suppression base layer and is easily dried. In addition, the foamed hydrothermal solidified body according to the present invention is alkaline because it is a material obtained by cementing incinerated ash into cement. Therefore, the land on which the weed control base layer is constructed becomes an environment unsuitable for plant growth.

  Conventionally, for the purpose of improving the scenery and softening the hearts of visitors, a flower bed, a planting zone of a median, etc. are generally provided during road maintenance. These flower beds and planting zones have good scenery at the time of planting and maintenance, but weeds will grow over time and in some cases will become a dumping place for garbage, so weeds will not grow as much as possible. Is desired. However, since weed control takes time and money, it cannot cope with the lack of weeding costs for landscape maintenance.

  Then, when preparing the flower bed and the planting zone of the center separation zone, the above-mentioned problem can be solved by forming the weed suppression base layer using the foamed hydrothermal solidified body according to the present invention.

  As a conventional method for controlling weeds, for example, Utility Model Registration No. 3029692 discloses an invention of a ground cover planting sheet that has a herbicidal effect and can plant ground cover plants in a labor-saving manner. Have been described. However, even in the above-mentioned ground cover planting sheet, (1) plants settled on the soil under the sheet gradually grow, so that weeds from the gaps around the sheet are particularly prone to grow, Even if it is not the periphery of the sheet, weeds that grow through the sheet through holes formed for greening are often seen, and weeds that have already penetrated once can no longer be expected to have a herbicidal effect. In addition, (2) because of the sheet, there is a risk that the sheet will be blown by wind or the like when the sheet pressing is poor, (3) insects and small animals are liable to live under the sheet, (4) water permeability of the sheet When there was a shortage, there was a problem that the sheet floated due to the outflow of topsoil, and there was room for improvement.

  On the other hand, if it is the method of weed control using a foaming hydrothermal solidification body for this invention, the subject which said ground cover planting sheet | seat will be cleared.

  Japanese Patent Application Laid-Open No. 2011-92098 discloses a herbicidal method, a soil material, and cement-based solidification that is easy to construct, has an excellent weed eliminating effect, has no adverse effects on the soil, and can be harmonized with the natural landscape. A kneading step in which an agent, an aggregating agent and water are mixed, a creation step in which the kneaded product formed in the kneading step is placed on the ground to form a planting layer, and a planting formed in the creation step An invention of a herbicidal construction method comprising a hole making step of forming a planting hole on the surface of a planting layer and a planting step of planting a seedling of a ground cover plant into the planting hole formed in the hole making step is disclosed. ing.

  However, in the herbicidal construction method described in JP 2011-92098 A, it is necessary to use an aggregating agent in order for the soil material and the cement solidifying agent particles to form a three-dimensional aggregated structure. is there. In addition, in order to aggregate in the kneading process, a large facility such as a mixer is required. For example, if there is a restriction on the work space of the construction site such as the central separation zone of the road, further construction is required. Cost becomes high.

  On the other hand, the foamed hydrothermal solidified body according to the present invention can form a weed suppression base layer corresponding to the planting layer just by spreading on the ground where weed control is desired, and no aggregating agent is required. No equipment for kneading is required.

  In addition, using a ground cover planting sheet described in the above-mentioned utility model registration No. 3029692 and a herbicidal construction method described in Japanese Patent Application Laid-Open No. 2011-92098, etc., the flower bed and the planting band are subjected to weed control treatment. However, it is often seen that a slight gap remains at the boundary between the area subjected to the weed suppression treatment and the outer frame formed of blocks or the like, and the weeds settle in this gap.

  In order to suppress such gap weeds, the foamed hydrothermal solidified product according to the present invention can be utilized as follows.

[Gap weed suppression treatment]
Specifically, after adjusting the particle size of the foamed hydrothermal solidified body so that the particle diameter is 5 mm or less, a material containing a cement-based solidifying agent and an amphoteric metal component (metal aluminum, etc.) is added, and water is added to mix and knead By filling the kneaded material obtained in this way into the gap between the weed suppression base layer and the outer frame as a gap weed suppression material, it is possible to effectively suppress the growth of gap weeds.

  Since the said clearance gap suppression material has expansibility, the clearance gap between a weed suppression base layer and an outer frame is completely filled up, when a clearance gap suppression material solidifies after filling. The kneaded product is preferably made into a slurry so that it can be easily filled according to the promotion of the expansion reaction and the state of the gap, and the amount of water can be appropriately adjusted so as to obtain a desired fluidity. is there.

  By combining the weed control method using the foamed hydrothermal solidified body according to the present invention described above with plants such as turf and flowers, weeds are eliminated and greening zones with a good landscape are obtained. Can be constructed in a labor-saving manner.

  For example, dwarf turf such as centipede grass is known as turf that suppresses weeds by fixing as lawn and reduces weeding work, but it suppresses the growth of other plants until it settles as lawn Management is necessary for this.

  Thus, by using the foamed hydrothermal solidified body according to the present invention, it is possible to realize a reduction in management load until the centipede glass is fixed. Hereinafter, a specific example of the “weed prevention / greening method” in which the foamed hydrothermal solidified body according to the present invention is combined with the dwarf turf will be described.

[1. Construction preparation process]
The upper part of the ground of the planting zone is peeled off at an arbitrary depth of about 5 to 30 cm, and all the remaining roots and the like of the ground off are removed. Also, carefully remove the soil and roots attached to the side surfaces of the surrounding structures (blocks, etc.) and the roots of existing trees with a brush or the like. The existing ground is leveled. Existing trees may be left behind.

[2. Weed control base layer formation process]
On the ground of the prepared planting zone, the foamed hydrothermal solidified product according to the present invention whose particle size has been adjusted is used as a weed control material, and about 5 to 30 cm is spread on the ground, and a predetermined hardness is obtained by a compactor such as a compactor. Consolidate. The soil hardness is 20 mm or more, and more preferably 25 mm or more as the “density” according to the Yamanaka type soil hardness meter.

[3. Crevice weed suppression treatment process]
Next, a gap of about 1 to 5 cm is formed in the peripheral portion, and a gap weed inhibitor is poured to prevent a gap from being opened between the concrete outer frame or the like in the peripheral portion and the weed control material spread. Since the crevice weed inhibitor cures relatively quickly, the surface is leveled with a trowel or the like after solidifying to some extent. In addition, it is preferable that the gap lower part is vacated so as to reach the existing ground.

[4. Cutting process for rooting material input hole]
Using a vibration drill or the like in the weed control base layer that has been constructed, a hole for extending the roots corresponding to the turf to be planted is made, thereby providing a root stretcher material injection hole. The hole is cut until weed control material is cut into the lower ground. The depth of biting is about the diameter of the root extension hole, or more. There are other methods for excavation of the root extension hole, and this is not restrictive.

  The above 2. When spreading the foam hydrothermal solidified body in the weed suppression base layer forming step, place a form of a predetermined shape such as a cylinder or box in advance on the existing ground, then spread the foam hydrothermal solidified body, It is good also as a root elongation material injection hole by pulling out a formwork after rolling. At that time, if a material that naturally decomposes is used as the mold, it is not necessary to pull out the mold.

[5. Root elongation material input process]
The root stretch material is made of a material that allows roots such as planted seedlings to easily descend the root stretch hole toward the existing ground. As materials, we mix and introduce soil materials such as sand and soil, fertilizer, and other optional materials. In the case of forming the root material input hole using a mold, this root extender can be put in the mold in advance. If this root stretcher filling planting method is used, it is possible to plant any plant with a short root length even if the weed suppression base layer is thick.

[6. Planting and sowing process]
A seedling of turf is planted or sown in the upper part where the root-growing material is added. The seedlings may be commercially available pot seedlings, but the stalks such as centipede glass are cut into about 10 to 20 cm, and the cut shoots are formed into a cross shape, a lattice shape, a spiral shape, or other shapes, A cross-shaped or brick / disk-shaped mat rooted and grown in an arbitrary seedling box may be planted at the top. After that, if the turf grows and turns into a lawn, the greening zone “Non-Glass Garden”, where weeds have been eliminated, is completed.

  In addition, if the nursery box of this stalk growth mat is kept at about 30 ° C. in a humidified state, it will start rooting immediately from the side bud of the stalk (runner). The length of extension was 17.8 mm / day. By using this method, it is possible to manage the seedlings in line with the construction site regardless of the season. By planting this rooted mat seedling, there is a merit that the stems (runners) can be extended and greening can be accelerated in a short period of time compared to the case of simply sowing or planting a pot seedling.

The greening zone “Non-Glass Garden” prepared as described above has the following advantages.
In other words, it has been pointed out that centipede grass has an allelopathic effect that hinders the growth of other plants, and a weed-suppressing effect due to the allelopathic effect is expected. In order to exert the allelopathic effect, it is important to grow the centipede grass stems faster than other weeds, and until the centipede grass covers the ground as some lawn, Means to suppress are needed.

  On the other hand, the greening zone “Non-Glass Garden” is a weed suppression base layer formed by using the foam hydrothermal solidified material according to the present invention, except for the root elongation material input hole, and is also subjected to crevice weed suppression treatment. Therefore, there is no need for management to control other weeds. Further, mat seedlings obtained by rooting and raising roots of the above-mentioned stems in an arbitrary shape are known to grow quickly, and are preferred because lawnization can be achieved earlier.

As a modified example of the “weed prevention / greening method”, the weed suppression base layer may be divided into two upper and lower layers, and a root growth layer may be provided between them.
If there is a possibility that weed sprouts from the existing ground may extend through the root-growing material insertion hole, this can be prevented by constructing as in the above-described modification.
The material of the “root extension growing layer” may be the same as the root extension material, or existing soil may be used or mixed, but naturally it is preferable that seeds and roots of weeds are not mixed.

Claims (10)

The manufacturing method of the foaming hydrothermal solidification body characterized by including the following processes (a)-(c).
(A) A mixing step of adding 5 to 25% by mass of cement to 100% by mass of incinerated ash containing an amphoteric metal, and mixing them;
(B) After the mixing step, kneaded water is added to the mixture of the incinerated ash and cement to knead to hydrate the quick lime contained in the incinerated ash and cement to obtain a kneaded product in a funicular state. Kneading process,
(C) After the kneading step, the kneaded product of the mixture of the incinerated ash and cement and the kneaded water is transferred to a mold and hydrothermally solidified while applying a predetermined compressive force, and the amphoteric metal contained in the incinerated ash A curing process to obtain a foamed hydrothermal solidified body by reacting with alkaline water to generate gas and foam.   The incineration ash is any one of incineration ash such as municipal waste, wood chips / tire chips, paper sludge, sewage sludge, biomass, or incineration ash such as coal, garbage solidified fuel, paper / plastic solidified fuel, etc. Or it is a mixture thereof, The manufacturing method of the foaming hydrothermal solidification body of Claim 1 characterized by the above-mentioned.   The method for producing a foamed hydrothermal solidified body according to claim 1, wherein the content of the amphoteric metal in the incinerated ash is 0.5 to 10% by mass.   In the mixing step of (a), lime is added to and mixed with the mixture, and the ratio thereof is 30 to 40% by mass of the total mixture. Production method.   2. The method for producing a foamed hydrothermal solidified body according to claim 1, wherein in the kneading step (b), 35 to 55 parts by mass of water is added and kneaded with respect to 100 parts by mass of the mixture.   In the mixing step (a), 15 to 25 parts by mass of water is mixed with 100 parts by mass of the mixture, and 20 to 30 parts by mass of water is added as the kneading water in the kneading step (b). The method for producing a foamed hydrothermal solidified body according to claim 1, wherein a predetermined amount is kneaded continuously successively.   2. The foam according to claim 1, wherein the mold is formed by a mold surrounded by a pothole dug in the ground or soil or a stone wall piled up to a predetermined height from the ground surface. A method for producing a hydrothermal solidified body. The surface bubble ratio is 0 to 22%, the BET specific surface area is 75 to 110 m ² / g, the water absorption is 40 to 63%, and the uniaxial compressibility is 5 to 18 N / mm ² . A foamed hydrothermal solidified product produced by any one of the production methods.   The embankment method using the foam hydrothermal solidification body of Claim 8 as a embankment material.   A herbicidal / greening method using the foamed hydrothermal solidified product according to claim 8.