JP2004224578A - Environmentally harmonized type calcium-containing hydrated hardened body and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmentally harmonized type hydrated hardened body without causing excessive increase of pH of ambient water in the case of being installed in the water to give a suitable environment to the surviving of underwater creature, also without causing excessive increase of pH of vegetable growing environment even in the use for vegetation basement or the like on the land to give a suitable environment to the growth of the vegetable. <P>SOLUTION: The Ca-containing hydrated hardened body has a calcium carbonate coating layer at least on the outer surface and has the calcium carbonate coating layer also on the continuous space inside surface in the case of porous body having the continuous space inside and a hydrated hardened body product or the hydrated hardened body placed on site is preferably used in a state provided under water, in contact with water or as the vegetation basement. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides, for example, an environment-friendly Ca-containing hydration that can provide a favorable habitat / growth environment for living organisms, for example, when it is installed in water, the organism has good adhesion (adherence) and good habitat / growth. The present invention relates to a cured product and a method for producing the same.
[0002]
[Prior art]
In recent years, seagrass reefs and materials for fishing reefs have been widely installed on the seabed in response to the problem of seagrass beds and fishing grounds deteriorating due to pollution of water and sediment in the coastal sea area and so-called sea scorching. Was. Concrete products such as concrete blocks are widely used as materials for such algae reefs and fishing reefs in terms of ease of production, stability in the sea, production costs, and the like. In addition, most of civil engineering materials used underwater or in the vicinity thereof, such as gutter blocks, waterway blocks, water purification blocks, and consolidation blocks, are mostly made of concrete products.
[0003]
[Problems to be solved by the invention]
However, when concrete is placed in water, there is a problem that Ca eluted from the concrete raises the pH of surrounding water and adversely affects the habitat and growth environment of underwater organisms (animals and plants, microorganisms). For this reason, even if a concrete block is simply installed on the seabed as a material for algae reefs, a sufficiently satisfactory amount of seaweed cannot be established and grown. In addition, it has been pointed out that concrete installed in the sea promotes the adhesion and propagation of lime algae, which causes so-called scorching, and furthermore, concrete installed in water, the lime contained therein is converted to calcium ions. There is also a problem that strength is reduced by elution into water.
[0004]
Conventionally, in order to promote the growth of seaweed on concrete blocks for algae reefs, unevenness or grooves are formed on the block surface, or an adhesion promoting substance is applied or attached, or an adhesion promoting substance is added to the block. (For example, Patent Literature 1, Patent Literature 2, Non-Patent Literature 1) have also been tried, but these countermeasures increase the cost of materials, and their effects are not always clear. However, it does not eliminate the disadvantage of concrete that raises the pH of the surrounding water.
[0005]
[Patent Document 1]
JP 2001-275506 A
[Patent Document 2]
JP-A-2002-45080
[Non-patent document 1]
"The 54th Annual Meeting of the Cement Technology Congress 2000" p. 410-411
[0006]
In addition, there is a problem similar to the above for concrete used in or around water other than materials for algae reefs and fishing reefs.For example, aquatic flora and fauna tend to hardly propagate in waterways made of concrete. .
In addition, for example, so-called porous concrete is also used for water purification materials and vegetation bases on land. In addition, there is a problem that the living environment is adversely affected, and when used as a vegetation base, the attached water such as rainwater and the pH of the surrounding water are increased, so that the growth of the plant is inhibited.
[0007]
Therefore, an object of the present invention is to provide a living body (animals and plants, microorganisms) for living organisms (animals and plants, microorganisms) without excessively increasing the pH of surrounding water when installed in water, even when the object is a hydrated hardened material such as concrete. Environmental harmony that can provide a suitable environment, and can provide a suitable environment for plant growth without excessively increasing the pH of the plant growth environment even when used for land vegetation bases, etc. It is an object of the present invention to provide a hydrated cured product of a mold and a method for producing the same.
[0008]
[Means for Solving the Problems]
As a result of repeated studies to solve the above-described problems, the present inventors formed a coating layer of calcium carbonate on the surface of a Ca-containing hydrated cured product typified by concrete so that when placed in water, Water does not excessively increase, nor does it excessively increase the pH of the plant growth environment when used for land vegetation bases, etc. It was found that an environment suitable for growth could be provided.
[0009]
The present invention has been made based on such findings, and the features thereof are as follows.
[1] An environmentally-friendly Ca-containing hydrated cured product having a calcium carbonate coating layer on at least the outer surface.
[2] The environmentally friendly Ca-containing hydrated hardened product of [1], which is a porous body having continuous voids therein, and having a calcium carbonate coating layer also on the inner surface of the continuous voids. Hydrated hardened body.
[3] The Ca-containing hydrated cured product according to the above [1] or [2], wherein the calcium carbonate coating layer is formed by carbonating the Ca-containing hydrated cured product. Environment-friendly Ca-containing hydrated cured product.
[4] The environment-friendly Ca-containing hydrated cured product according to any one of the above [1] to [3], which is a hydrated cured product cast in situ.
[0010]
[5] The hydrated cured product according to any one of the above [1] to [4], which is used in a state of being immersed in or in contact with water or used as a vegetation base, or An environmentally friendly hydrated cured product containing Ca, which is a hydrated cured product cast in situ.
[6] A Ca-containing hydrated hardened material having water adhered to at least the outer surface or at least a surface layer of which is impregnated with water is subjected to a carbonation treatment in a carbon dioxide gas atmosphere or a carbon dioxide gas-containing atmosphere, and the Ca-containing hydrated hardened material surface layer is formed. A method for producing an environment-friendly Ca-containing hydrated hardened product, comprising: forming a calcium carbonate coating layer on at least the outer surface of a Ca-containing hydrated hardened product by carbonating uncarbonated Ca contained in the hydrated Ca-containing product.
[7] In the production method according to the above [6], the Ca-containing hydrated cured product has continuous voids therein, and carbonates uncarbonated Ca contained in the inner surface layer of the continuous voids by carbonation treatment. And a method for producing an environment-friendly Ca-containing hydrated cured product, wherein a calcium carbonate coating layer is also formed on the inner surface of the continuous void.
[0011]
[8] In the method of the above-mentioned [7], after the Ca-containing hydrated cured product having continuous voids therein is impregnated with water, the pressure inside the Ca-containing hydrated cured product is reduced to reduce the water content. And then subjecting the Ca-containing hydrated cured product to a carbonation treatment under a carbon dioxide gas atmosphere or a carbon dioxide gas-containing atmosphere to obtain a carbon-containing hydrated cured product surface layer and an uncarbonated material contained in the inner surface layer of the continuous voids. A method for producing an environment-friendly cured hydrated Ca-containing material, wherein a calcium carbonate coating layer is formed on the outer surface of the hydrated hydrated Ca-containing material and on the inner surface of the continuous voids by carbonating hydrated Ca.
[9] In the manufacturing method according to the above [8], in the step of depressurizing the inside of the Ca-containing hydrated cured product, the inside of the Ca-containing hydrated cured product is depressurized to 0.8 atm or less. A method for producing a hydrated cured product containing type Ca.
[10] In the production method according to any one of the above [6] to [9], in the step of carbonating the Ca-containing hydrated cured product, the Ca-containing hydrated cured product is placed in an airtight container, A carbon-containing hydrated cured product by supplying carbon dioxide gas or a carbon dioxide-containing gas to the mixture, thereby producing an environment-friendly hydrated hydrated Ca-containing product.
[0012]
[11] In the production method according to any one of the above [7] to [9], in the step of carbonizing the Ca-containing hydrated cured product having continuous voids therein, An environment-friendly Ca-containing water, wherein the Ca-containing hydrated hardened product is carbonated by supplying carbon dioxide gas or a carbon dioxide-containing gas from the outer surface of the Ca-containing hydrated hardened product to the inside thereof through means. A method for producing a cured product.
[12] The method for manufacturing according to [11], wherein the carbon-containing gas or the carbon-containing gas is supplied to the Ca-containing hydrated cured product placed in the container through a gas supply means. A method for producing a cured product.
[13] In the production method according to any one of the above [7] to [9], the Ca-containing hydrated cured product has continuous voids inside, and has a hole reaching from the outer surface to the inside of the hydrated cured product, In the step of carbonating the hydrated hardened product, the carbon-containing hydrated hardened product is carbonated by supplying a carbon dioxide gas or a carbon dioxide-containing gas into the hole from a gas supply means. A method for producing a hydrated cured product containing harmonic Ca.
[14] The method of [13], wherein the carbon-containing gas or the carbon-containing gas is supplied from the gas supply means into the hole of the Ca-containing hydrated cured product placed in the container. A method for producing a Ca-containing hydrated cured product.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Although the Ca-containing hydrated cured product of the present invention has a calcium carbonate coating layer on at least the outer surface, the Ca-containing hydrated cured product serving as a substrate is not limited as long as it contains uncarbonated Ca. Regardless of the type. Here, the Ca-containing hydrated hardened product is a binder containing Ca (such as cement), an aggregate (fine aggregate and / or coarse aggregate), water, and an admixture optionally blended. Kneaded, hydrated and hardened, or a Ca-containing material with a wide particle size distribution from binder to aggregate, kneaded with water, admixture blended as necessary, etc., and hydrated and hardened It is a thing. The most common Ca-containing hydrated hardened body is concrete, but is not limited thereto. For example, FS concrete, eco-cement concrete, coal ash hydrated hardened body (eg, fly ash cement concrete), Any Ca-containing hydrated hardened product such as a hydrated hardened product containing slag generated in the steelmaking process as a main raw material (for example, a hydrated hardened product containing molten iron pretreated slag, blast furnace slag fine powder, slaked lime, etc.) Can be targeted.
The concrete includes concrete using arbitrary cement such as Portland cement and blast furnace cement.
[0014]
Further, when continuous voids (open pores) are formed inside these Ca-containing hydrated cured products, a calcium carbonate coating layer is preferably formed also on the inner surface of the continuous voids (main continuous voids). A typical example of the Ca-containing hydrated cured product having such continuous voids is a so-called porous concrete (porous concrete), but is not limited thereto. In general, porous concrete has a continuous porosity of 10% or more (based on the continuous porosity measurement method in Appendix-8 of “Drainable Pavement Technology Guideline (draft)” issued by the Japan Road Association). Normally, porous concrete is obtained by mixing a coarse aggregate and a cement paste at a fixed ratio and kneading the mixture.
The method of forming the calcium carbonate coating layer on the outer surface of the Ca-containing hydrated cured product or the inner surface of the continuous voids is optional, but is usually formed by a carbonation treatment in which the Ca-containing hydrated cured product is brought into contact with carbon dioxide gas. The method of performing the carbonation treatment will be described later in detail.
The Ca-containing hydrated hardened product targeted by the present invention includes not only a hydrated hardened product (solidified product) such as a block, but also a hydrated hardened product to be applied on site such as cast-in-place concrete.
[0015]
There are no particular restrictions on the type of hydrated cured product or cast-in-place hydrated cured product that is the subject of the present invention, but those used in or near water, those used in contact with water, vegetation bases Those used as are particularly preferred. Specifically, in the sea, rivers, lakes, marshes, etc., for algae reefs, rocky shores, fish reefs, for seabed mounds, for riverbeds, for fishways (for example, fishways provided in dams and weirs), for artificial riverbeds (for example, stones) Hydrated hardened product or cast-in-place hydrated hardened product to be immersed in water for various uses such as for riverbed constructed by upholstery or stonework, and for water purification; gutter block (U-shaped gutter block, L-shaped gutter block, Hydrated hardened products or cast-in-place hydrated products for waterways, such as variable slope type gutter blocks (open bottom gutter blocks), open or culvert waterway blocks, retaining wall blocks, waterway bottom blocks, etc. Hydration-hardened products or cast-in-place hydration products used as vegetation bases such as greening blocks, landscape blocks, soil covering blocks (blocks for seawall construction, blocks for sloping land covering, slope stabilizing blocks, etc.) Body, and the like.
The Ca-containing hydrated cured product of the present invention can be used for various purposes other than the above-described submerged materials, waterway materials, and vegetation base materials.
[0016]
Hereinafter, the function of the Ca-containing hydrated cured product of the present invention will be described.
The formation and propagation of seaweed on the algae reef material (seaweed epithelial substrate) installed in the water is several μm to several hundred μm released from sporophytes (parent individuals) growing elsewhere. Small zoospores and eggs float in the seawater, reach the substrate, settle on the surface, and then grow into sporophytes and juveniles. For the settlement, the water quality of the seawater in contact with the substrate surface, especially the water layer of the small seawater layer with low fluidity (the so-called boundary layer) existing on the substrate surface is suitable for the settlement and growth of zoospores and eggs. It seems necessary to have something. In the conventional concrete substrate (material), Ca eluted from the concrete greatly increases the pH of the surrounding water, particularly a minute seawater layer in contact with the surface of the substrate, and as a result, the substrate floats in the seawater to form a substrate. It is thought that the zoospores and eggs that arrived could not settle and grow well on the substrate surface. Normal seawater is a weak alkali having a pH of about 7.8 to 8.4, and if its pH exceeds 10, it is considered that the formation and growth of zoospores and eggs are significantly inhibited. In the case of (material), the pH of the boundary layer existing on the surface of the substrate is as high as about 12, and this boundary layer can be said to be an environment in which zoospores and eggs are extremely difficult to set and grow.
[0017]
On the other hand, the Ca-containing hydrated cured product of the present invention has a calcium carbonate coating layer formed on its surface (the surface including the inner surface of the continuous void if it has continuous voids). The elution and the accompanying increase in pH of seawater (especially, seawater in the boundary layer on the surface of the substrate) are suppressed, and the seawater layer on the surface of the substrate can be set as an environment suitable for the formation and growth of zoospores and eggs. The function of the Ca-containing hydrated cured product of the present invention is not limited to the case where it is installed for algae reefs and fishing reefs, but also the case where it is installed in water as various materials such as for construction of shores and sea bottom mounds. It works similarly. In addition, examples of the settled animals and plants include seaweeds, corals, shellfish, barnacles, and mosquitoes, but are not limited thereto.
In addition, the Ca-containing hydrated cured product of the present invention is applied to hydrated cured products (blocks, etc.) and cast-in-place hydrated cured products such as for waterways such as irrigation canals, fishways provided for dams and weirs, and artificial riverbeds. In this case, for the same reason as described above, it is possible to provide an environment where underwater organisms (fish, crustaceans, aquatic insects, etc.) and aquatic plants (algae, aquatic plants, etc.) can easily live and grow.
[0018]
Conventionally, as one method for purifying the water quality of the sea, rivers, lakes, marshes, ponds, etc., the aim was to use the self-cleaning action of the ecosystem of living organisms, especially microorganisms, and to promote the activity between living organisms in the water. 2. Description of the Related Art In order to artificially provide an environment of a food chain, a porous concrete block has been installed as a water purification material underwater or on the waterside. By the way, in order to provide an environment where water quality self-cleaning action by the food chain of living organisms can be obtained properly by using water purification material, the material itself attaches and propagates aerobic microorganisms that decompose organic pollutants, And that they have an environment in which they can be active, and that they have an environment in which protozoa that prey on these microorganisms can be active, and that algae that take in degradation products of organic pollutants as nutrient sources It is necessary to provide an environment in which aquatic plants such as can grow and grow. In this regard, the conventional porous concrete material has a large problem in both the survival environment of aerobic microorganisms and the growth environment of algae because the pH of the water inside and around the porous material is increased (for example, Nitrifying bacteria are suitable environments at pH 7-9), but may even worsen their environment.
[0019]
On the other hand, when the Ca-containing hydrated cured product of the present invention is used as a water purification material, there is almost no possibility of increasing the pH of the water inside or around the porous material, and therefore the survival of aerobic microorganisms The environment and the growth environment of algae are not inhibited by the increase in pH, and therefore, have a high biological carrier function (particularly, a carrier function of aerobic microorganisms) and a high function as a vegetation base for aquatic plants and wet plants. . This effectively promotes the decomposition of organic pollutants and the nitrification of nitrogen compounds by microorganisms, and promotes the absorption of nutrients by plants by providing a growth environment for aquatic plants such as algae and also for wet plants. These effects can effectively promote the water purification ability of the ecosystem of organisms, mainly microorganisms.
Further, when the Ca-containing hydrated cured product of the present invention is installed in water, the elution of Ca as a component thereof into water (elution as Ca ions) is suppressed, and the strength in water is also reduced. It is unlikely to occur.
[0020]
Next, a method for producing the Ca-containing hydrated cured product of the present invention will be described.
In the method for producing a Ca-containing hydrated cured product of the present invention, a carbon-containing gas atmosphere or a carbon-containing gas-containing atmosphere (hereinafter referred to for convenience) is applied to the Ca-containing hydrated cured product in which water is adhered to at least the outer surface or at least the surface layer is impregnated with water. These are collectively referred to as “carbon dioxide atmosphere”), and carbonation is performed under non-carbonated Ca contained in the surface layer of the Ca-containing hydrated hardened body, thereby at least the Ca-containing hydrated hardened body is carbonated. A calcium carbonate coating layer is formed on the outer surface.
[0021]
In order to efficiently perform the carbonation treatment of the outer surface of the Ca-containing hydrated cured product, it is essentially essential that water (surface-adhered water) be present on the surface of the Ca-containing hydrated cured product. It is necessary to make water adhere to at least the outer surface of the contained hydrated cured product, or to impregnate at least the surface layer with water. That is, uncarbonated Ca and CO contained in the surface layer of the Ca-containing hydrated cured product in the carbonation treatment ₂ The mechanism of the reaction with water is that the water (surface adhering water) ₂ Is dissolved, and Ca ions are eluted from the hydrated cured body, and the CO dissolved and eluted in the water ₂ Reacts with Ca ions (carbonation reaction) to cause CaCO ₃ Is considered to precipitate. Therefore, in order to cause carbonation by the above mechanism, it is necessary that water (water adhering to the surface) be present on the surface of the hydrated cured product.
The method of adhering or impregnating water to the Ca-containing hydrated cured product is optional. For example, a method of immersing the hydrated cured product in water, a method of sprinkling water on the hydrated cured product, or the like may be employed. Can be. In the present invention, water is adhered to at least the outer surface of the Ca-containing hydrated cured product or at least the surface layer is impregnated with water by these methods.
[0022]
The specific method of the carbonation treatment is optional. For example, a Ca-containing hydrated cured product to which water is adhered or impregnated with water as described above is sealed in a closed container (a container capable of maintaining airtightness). The carbonation treatment is performed by supplying carbon dioxide gas or a carbon dioxide-containing gas (hereinafter collectively referred to as “carbon dioxide gas” for convenience) into the closed container. FIG. 1 shows an embodiment of the carbonation treatment, in which a Ca-containing hydrated cured product A to which water is adhered or impregnated with water as described above is placed in a closed container B, and the closed container B Carbonation is performed by supplying carbon dioxide through the gas supply system C. At this time, the gas supplied into the closed container B may be appropriately discharged through the gas discharge system D.
By the above carbonation treatment, a calcium carbonate coating layer is formed on the outer surface of the Ca-containing hydrated cured product. In addition, some of the Ca-containing hydrated cured products have continuous voids therein, though to varying degrees, and the Ca-containing hydrated cured products having such continuous voids are continuously subjected to carbonation treatment. Uncarbonated Ca contained in the inner surface layer of the void is also carbonated, and a calcium carbonate coating layer is formed on the inner surface of the continuous void.
[0023]
In the case of a Ca-containing hydrated hardened product having continuous voids therein, particularly in the case of so-called porous concrete, the Ca-containing hydrated hardened product is impregnated with water (in this case, water is introduced to the inside of the hydrated hardened product). ), And a part of the water is discharged by depressurizing the inside of the Ca-containing hydrated cured product. Thereafter, the Ca-containing hydrated cured product is preferably subjected to a carbonation treatment under a carbon dioxide gas atmosphere. . Thereby, uncarbonated Ca contained in the Ca-containing hydrated cured product surface layer and the inner surface layer of the continuous voids is appropriately carbonated, and the outer surface of the Ca-containing hydrated cured product and the inner surface of the continuous voids are coated with a calcium carbonate coating layer. Can be appropriately formed.
[0024]
Uncarbonated Ca and CO contained in the surface layer of the Ca-containing hydrated cured product ₂ The basic reaction mechanism is as described above, but the carbonation treatment of the hydrated cured product having continuous voids inside causes carbonation of uncarbonated Ca contained in the inner surface layer of the continuous voids. Means that water (surface adhering water) is present on the inner surface of the continuous void and CO ₂ Routes need to be properly secured. However, simply impregnating the Ca-containing hydrated cured product with water by a method such as water spraying prior to the carbonation treatment may cause excessive water to be impregnated in the continuous voids (in extreme cases, the entire continuous voids may be impregnated with water). Filling) or a continuous void that is partially impregnated with water. As a result, where water is high, CO ₂ CO is not secured due to insufficient route ₂ Does not flow sufficiently, which makes it difficult for the carbonation reaction to occur. ₂ Because the route of the road is sufficiently secured ₂ Flows, but the amount of Ca ions eluted from the inner surface of the continuous voids is small because the essential water content is small. In this case, it is considered that the carbonation reaction is unlikely to occur. And as a result, it becomes difficult to form a calcium carbonate coating layer uniformly over the entire continuous voids.
[0025]
The present inventors have studied a method capable of coping with such a problem, and as a result, after sufficiently containing water inside the Ca-containing hydrated cured product, the inside of the hydrated cured product is decompressed to reduce the water. It is very effective to discharge a part (that is, excess water other than the water adhering to the inner surface of the continuous void) and then cause a carbonation reaction in the Ca-containing hydrated cured product in a carbon dioxide gas atmosphere. I found something. The principle that the distribution state of water in the continuous voids of the Ca-containing hydrated cured product is made uniform by such a method will be described based on FIG. 2 (schematic diagram).
[0026]
FIG. 2A shows a state in which water is sufficiently contained in the connection gap inside the Ca-containing hydrated cured product. In this state, water is present in many continuous voids of the Ca-containing hydrated cured product, and bubbles are present in the void water. These bubbles are bubbles trapped in continuous voids when water is contained in the Ca-containing hydrated cured product, and such bubbles are widely present throughout the Ca-containing hydrated cured product. Then, when the Ca-containing hydrated cured product is decompressed in this state, the bubbles in the pore water greatly expand as shown in FIG. 2 (b), and the bubbles push the pore water to the outside of the Ca-containing hydrate cured product. Specifically, as shown in FIG. 2 (c), most of the pore water flows out of the Ca-containing hydrated hardened material except for the water adhered to the inner surfaces of the continuous pores (water adhering to the surface). In other words, not only is it unnecessary for the carbonation reaction, but also the CO ₂ Most of the water that hinders the passage of water is removed from inside the Ca-containing hydrated cured product. On the other hand, when there is a continuous void partially impregnated with water, water was not impregnated due to the discharge of water from the continuous void (movement of water in the continuous void) during the pressure reduction. Water also moves to the continuous void, and water adheres to the inner surface of the continuous void. As a result, the water adhering to the surface is uniformly present in the entire continuous voids and the CO ₂ A state in which the path is appropriately secured is realized over the entire continuous voids of the Ca-containing hydrated cured product.
[0027]
Then, by causing a carbonation reaction in the carbon-containing gas atmosphere to the Ca-containing hydrated hardened material in which the distribution state of water (gap water) is optimized as described above, the entire continuous voids of the Ca-containing hydrated hardened material are formed. As a result, the carbonation reaction proceeds efficiently and uniformly, and the calcium carbonate coating layer is uniformly formed not only on the outer surface of the Ca-containing hydrated cured product but also on the inner surface of the continuous void.
In the above method, the method of impregnating the Ca-containing hydrated cured product with water is arbitrary, for example, by immersing the Ca-containing hydrated cured product in water, spraying water on the Ca-containing hydrated cured product, and the like. Can be impregnated with water, but in any case, it is preferable that the internal continuous voids be sufficiently impregnated with water.
[0028]
Further, with respect to the Ca-containing hydrated cured product impregnated with water as described above, a method of depressurizing the inside is also optional. For example, the Ca-containing hydrated cured product is contained in a closed container equipped with an exhaust (suction) mechanism such as a vacuum pump. The hydrated cured product may be accommodated, and the pressure inside the airtight container may be reduced.
There is no particular limitation on the degree of decompression in the depressurization step. However, in order to quickly discharge excess water inside the Ca-containing hydrated hardened product, the inside of the Ca-containing hydrated hardened product (the inside of the continuous gap) should be reduced to 0%. The pressure is preferably reduced to 0.8 atm or less, more preferably 0.2 atm or less.
After the inside of the Ca-containing hydrated cured product is depressurized to discharge excess water (void water), the Ca-containing hydrated cured product is subjected to a carbonation treatment in a carbon dioxide gas atmosphere.
[0029]
A specific method for carbonating the Ca-containing hydrated cured product having continuous voids inside is arbitrary, and for example, the following method can be employed.
{Circle around (1)} The Ca-containing hydrated cured product is placed in an airtight container (a container capable of maintaining airtightness), and carbon dioxide gas is supplied into the closed container to cause carbon dioxide gas to enter the continuous voids inside the hydrated cured material. How to infiltrate
{Circle around (2)} A method in which carbon dioxide gas is supplied from the outer surface of the Ca-containing hydrated cured product through the gas supply means to the inside thereof, thereby flowing carbon dioxide gas into continuous voids inside the hydrated cured product.
{Circle around (3)} By forming a hole reaching the inside from the outer surface of the Ca-containing hydrated hardened body and supplying carbon dioxide gas into the hole from a gas supply means, the hole is directed from the inside of the hole to the outer surface side of the hydrated hardened body. To flow carbon dioxide gas through continuous voids
[0030]
Here, when the Ca-containing hydrated cured product having continuous voids inside is subjected to the carbonation treatment by the above method (1), substantially CO 2 is used as a treatment gas. ₂ Plain (CO ₂ : 100%) or a gas having a composition close thereto is used. ₃ Disappears from the gas phase as a part of ₂ One after another in the space where disappeared ₂ Is supplied. Therefore, even if the Ca-containing hydrated cured product is relatively thick, an efficient carbonation treatment can be performed. On the other hand, CO as a processing gas ₂ And other gas components (eg, N ₂ , H ₂ O), a gas containing CO ₂ Disappears from the gas phase, other gas components remain, and these gas components are ₂ Supply (CO ₂ Supply by diffusion of molecules). For this reason, when the thickness of the Ca-containing hydrated cured product is relatively small, there is no major problem, but when the thickness is large, the efficiency of the carbonation treatment is reduced.
In this regard, the methods (2) and (3) are not batch type as in the method (1), but a processing gas is continuously flowed into the Ca-containing hydrated cured product (continuous voids), Since the carbonation is performed by this gas flow, an efficient carbonation can be performed even for a Ca-containing hydrated cured product having a relatively large thickness. The above carbonation treatment methods (1) to (3) can be carried out irrespective of whether or not the above-described water impregnation and the subsequent pressure reduction are performed prior to the carbonation treatment.
[0031]
FIG. 3 shows an embodiment of the method of the present invention in which after the Ca-containing hydrated cured product is impregnated with water, the pressure is reduced, and then the carbonation treatment is performed by the method (1).
The processing container 1 to be used is a container that can be made substantially airtight. In the present embodiment, the processing container 1 includes a main body 100 and a lid 101 that closes an upper part thereof. A gas supply / exhaust pipe 3 is connected to the main body 100. The gas supply / exhaust pipe 3 has a gas supply pipe system 4 for supplying carbon dioxide gas and a suction for reducing pressure in the processing vessel 1. A suction pipe system 5 having a pump 6 is connected. Further, an exhaust pipe 7 for exhausting the gas supplied into the processing container 1 is connected to an upper portion of the processing container 1. In addition, in the drawings, reference numerals 8 to 10 denote on-off valves provided in each piping system.
[0032]
The Ca-containing hydrated cured product A is charged into the processing container 1. In the method of the present invention, first, the Ca-containing hydrated cured product A is impregnated with sufficient water. As a method, while the upper portion of the processing container 1 is open, the entire processing container is immersed in water in a water tank. Alternatively, a sufficient amount of water may be sprayed from above the Ca-containing hydrated cured product A. In addition, the Ca-containing hydrated cured product A may be impregnated with water by immersion or water spraying before being placed in the processing container 1.
After the Ca-containing hydrated cured product A was sufficiently impregnated with water as described above, the lid 101 was attached to make the processing container 1 airtight, and then the suction pump 6 of the suction pipe system 5 was used. The inside of the processing container 1 is exhausted by suction. As a result, the pressure inside the Ca-containing hydrated hardened product A (processing vessel) is reduced, and the air and water (pore water) in the continuous voids of the Ca-containing hydrated hardened product A are extruded from the hydrated hardened product. Is discharged from As a result, in the Ca-containing hydrated cured product A, the appropriate distribution state of water (gap water) as described above, that is, the water adhered to the surface is uniformly present on the inner surface of the continuous gap, and CO is contained in the continuous gap. ₂ A state where the path of the route is appropriately secured is realized.
[0033]
Next, the suction pipe system 5 and the gas supply pipe system 4 are switched by operating the on-off valves 8 and 9, and carbon dioxide gas is supplied from the gas supply pipe system 4 into the processing vessel 1 for a certain period (for example, several hours to several hundred hours). Supply). Part of the carbon dioxide gas supplied into the processing vessel 1 causes a carbonation reaction on the outer surface of the Ca-containing hydrated cured product A and in the continuous voids. The remainder of the carbon dioxide gas is discharged from the exhaust pipe 7 to the outside of the processing vessel 1. In some cases, carbon dioxide gas may be supplied into the processing vessel 1 with the on-off valve 10 of the exhaust pipe 7 closed, but in this case, the on-off valve 10 is occasionally opened and the processing vessel is opened. It is preferable that the gas accumulated in the processing vessel 1 is released so that the concentration of carbon dioxide in the processing vessel 1 is maintained at a predetermined level or more. After the above-described supply of carbon dioxide gas is performed for a certain period, the Ca-containing hydrated cured product A is taken out of the processing container 1.
[0034]
FIG. 4 shows an embodiment in which the carbonation treatment is carried out by the above method (2). The gas supply wind box 11 (gas supply means) facing the lower surface of the Ca-containing hydrated cured product A ), So that the carbon dioxide gas supplied into the wind box 11 is supplied from the lower surface of the Ca-containing hydrated cured product A to the inside thereof. As a result, a flow of carbon dioxide gas is formed from the lower surface of the Ca-containing hydrated cured product A to the inside and further to the upper surface (further, the side surface), and carbonation is performed by the carbon dioxide gas.
FIG. 5 shows an embodiment in which the above method (2) is performed in a container having an appropriate airtightness. In this embodiment, a perforated plate 110 or the like is used at the bottom of the container E. A wind box 11a (gas supply means) was provided, and the Ca-containing hydrated cured product A was placed on the wind box 11a (on the perforated plate 110), and a carbon dioxide gas was supplied into the wind box 11a and provided in the container E. A part of the gas in the container E is exhausted from the gas discharge system F. According to this method, the amount of gas discharged from the gas discharge system F is controlled and the inside of the container is set to an appropriate pressure condition, so that the carbonation from the outer surface side of the Ca-containing hydrated cured product A also proceeds efficiently. I can make it.
In the above method (2), the surface of the Ca-containing hydrated cured product to which carbon dioxide gas is supplied from the gas supply means is not limited to the lower surface, but may be any surface (for example, a side surface, an upper surface, etc.). As shown in FIGS. 4 and 5, the side surface of the Ca-containing hydrated cured product A is sealed with a seal 15, and carbon dioxide gas is supplied from one surface to the opposite surface of the Ca-containing hydrated cured product A (the lower surface in this embodiment). To the upper surface).
[0035]
FIG. 6 shows an embodiment in which the carbonation treatment is carried out by the above method (3). A hole 12 reaching the center is formed in advance, and carbon dioxide gas is supplied to the hole 12.
Examples of the method of forming the holes 12 include a method of embedding a tube 13 such as a metal tube in a raw material when manufacturing the hydrated cured body A as in the present embodiment, and a method of manufacturing the hydrated cured body A. Of forming a hole in a part of a mold (any member that can be removed after curing of a hydrated cured product) at the time of forming, and piercing the manufactured hydrated cured product A with a piercing means Or any other appropriate method. As the means for supplying carbon dioxide gas into the hole 12, any gas supply means such as a gas supply pipe 14 which can be inserted into the hole 12 as shown in FIG. 6 can be used. The carbon dioxide gas supplied into the hole 12 forms a gas flow from the inside of the Ca-containing hydrated cured product A to the outer surface side, and the carbonation gas is used to perform a carbonation treatment.
[0036]
FIG. 7 shows an embodiment in which the above method (3) is performed in a container having an appropriate airtightness. In this embodiment, for example, the gas inlet 14a (gas Supply means), the Ca-containing hydrated cured product A is placed in the container E such that the gas inlet 14a and the hole 12 coincide with each other, and carbon dioxide gas is supplied from the gas inlet 14a into the hole 12 and A part of the gas in the container E is exhausted from a gas discharge system F provided in E. According to this method, the amount of gas discharged from the gas discharge system F is controlled, and the inside of the container E is set to an appropriate pressure condition, so that carbonation from the outer surface side of the Ca-containing hydrated cured product A can be efficiently performed. Let it proceed.
In the above method (3), the size and depth (position of the hole tip) of the hole 12 formed in the Ca-containing hydrated cured product A and the number of holes are arbitrary, but the depth of the hole is Ca It is preferable that the hydrated cured product A reaches substantially the center or its vicinity.
[0037]
Further, the method of the present invention can also be applied to a cast-in-place Ca-containing hydrated cured product. In this case, water is adhered to at least the outer surface of the in-situ cured Ca-containing hydrated body, or at least the surface layer is impregnated with water, and a closed space surrounding the outer surface of the Ca-containing hydrated cured body is formed. Then, a carbon dioxide gas is supplied or a carbon dioxide gas generation source is placed in the closed space, and the non-carbonated Ca contained in the surface layer of the Ca-containing hydrated hardened body is carbonated, so that at least the Ca-containing hydrated hardened body is obtained. A calcium carbonate coating layer is formed on the outer surface. When the Ca-containing hydrated cured product has continuous voids inside, the uncarbonated Ca contained in the inner surface layer of the continuous voids is also carbonated by the carbonation treatment, and the inner surface of the continuous voids is also carbonated. A calcium coating layer is formed.
For example, in installing a waterway or a gutter, when all or a part of these civil engineering structures (for example, only the bottom portion in the case of a lower open type gutter) is formed from a cast-in-place hydrated and hardened body, a constructed waterway is used. Alternatively, both ends of the gutter and the opening at the top are closed by appropriate means (for example, a sheet or the like) to form a closed space inside the constructed waterway or gutter, and supply or supply of carbon dioxide gas into the closed space. Put source. As a result, a calcium carbonate coating layer is formed on the outer surface of the cast-in-place hydrated cured product constituting the inner surface of the water channel or the gutter.
[0038]
Examples of the carbon dioxide or carbon dioxide-containing gas used to cause a carbonation reaction in the Ca-containing hydrated cured product include, for example, a lime burning plant exhaust gas (usually CO 2) discharged in an integrated steel mill. ₂ : Around 25%) and heating furnace exhaust gas (usually CO ₂ : About 6.5%) and the like, but are not limited thereto. In addition, CO in gas ₂ If the concentration is too low, there is a problem that the processing efficiency is reduced, but the other problems are not exceptional. Therefore, CO ₂ The concentration is not particularly limited, but in order to perform an efficient treatment, the concentration of ₂ The concentration is preferably set.
Although there is no particular limitation on the supply amount of carbon dioxide gas, a general standard is 0.004 to 0.5 m. ³ It is sufficient that a gas supply amount of about / min · t (a hydrated cured body ton) can be secured. Although there is no particular restriction on the gas supply time (carbonation time), the standard is 15 m per 1 t of the hydrated cured product. ³ Above, preferably 200m ³ It is preferable to supply gas until the above carbon dioxide gas is supplied.
[0039]
The supplied carbon dioxide gas or carbon dioxide-containing gas may be at room temperature, but if the temperature of the gas is higher than room temperature, it is advantageous because the reactivity increases accordingly. However, if the temperature of the gas is excessively high, the moisture impregnated in the Ca-containing hydrated cured product may be dried or CaCO 2 ₃ Is CaO and CO ₂ Therefore, even when a high-temperature gas is used, it is necessary to use a gas having a temperature that does not cause such decomposition.
Further, the carbon dioxide gas or the carbon dioxide-containing gas is preferably supplied in a humidified state in order to prevent the Ca-containing hydrated cured product from drying. Therefore, carbon dioxide or carbon dioxide-containing gas is blown into water once ₂ It is preferable to supply O after saturating it, whereby the Ca-containing hydrated cured product can be prevented from drying and the carbonation reaction can be promoted.
[0040]
【Example】
[Example 1]
Concrete plate of 25 cm x 25 cm x 5 cm (Portland cement: 258 kg / m ³ , Fine aggregate: 892 kg / m ³ , Coarse aggregate: 988 kg / m ³ , Water: 170 kg / m ³ Were hydrated and hardened, and this was cured for 28 days to produce 50 concrete blocks), sprinkling water on 25 of them, and then having an inner volume of 3 m ³ And the pressure was reduced to 0.2 atm. Next, CO ₂ 500m over 10 days containing 25% ³ And subjected to a carbonation treatment. Note that the closed container had a gas exhaust portion, and a part of the exhaust gas introduced into the container during the carbonation treatment was sequentially discharged from the gas exhaust portion.
[0041]
A natural rock reef at a depth of 6 m near the natural seaweed bed was selected as a test seaweed bed creation site, and the above 25 carbonized concrete plates (example of the present invention) and the remaining 25 uncarbonated concrete plates Concrete plates (comparative examples) were attached to the natural reefs with an underwater adhesive. This concrete plate should be installed just before spores are released from the seaweed in the natural seaweed bed to prevent sediment in the sea from covering the surface of the concrete plate before spores of seaweed adhere. I chose the time (October).
Inspection of the above concrete plate about half a year later confirmed that seaweeds (mainly scallops) settled and grew on all concrete plates, but the concrete plate of the comparative example averaged On the other hand, while about 30 bamboo shoots settled and grew, on the concrete plate of the present invention example, about 70 bamboo shoots settled and grew on average. It was confirmed that the growth rate and growth rate of the cultivar were good.
[0042]
[Example 2]
Size: 1m x 1m x 0.5m, continuous porosity: 20% porous concrete block (Portland cement: 296kg / m ³ , Coarse aggregate: 1485 kg / m ³ , Water: 59kg / m ³ Is kneaded, hydrated and hardened, and sprinkled on a porous concrete block (cured for 28 days). ³ And the pressure was reduced to 0.2 atm. At this time, since the water discharged from the porous concrete block accumulated in the lower part of the closed container, the pressure in the closed container was restored to remove the water in the container, and the pressure was reduced again. Next, the porous concrete block was filled with an internal volume of 10 m. ³ Replace with a closed container of ₂ 10m exhaust gas containing 30% ³ It was introduced and sealed in a container. When the reaction (carbonation) was carried out for 2 days in this gas-filled state, the CO in the exhaust gas introduced into the container was determined from the pressure in the container measured by a pressure gauge. ₂ It was found that 80% of the gas was consumed in the carbonation reaction. ₂ : 30%), the exhaust gas was sealed in a container, and reacted (carbonated) for 2 days in this state. The carbonation treatment was repeated 10 times in total, in which the above-described process of exchanging the exhaust gas in the closed container and reacting for 2 days was repeated 10 times.
After the carbonation treatment was completed, the amount of carbonated CaO was calculated from the decrease in the gas pressure in the vessel in the above-described repetitive steps. As a result, it was found that about 2 mass% of CaO content of the concrete was carbonated.
[0043]
【The invention's effect】
The Ca-containing hydrated cured product of the present invention described above does not excessively raise the pH of surrounding water when placed in water, and provides an environment suitable for the survival of living organisms (animals, plants, microorganisms, etc.) in water. In addition, even when used for a land-based vegetation base or the like, it is possible to provide an environment suitable for plant growth without excessively increasing the pH of the plant growth environment. Furthermore, since the elution of Ca (Ca ion) when installed in water is suppressed, a decrease in strength in water and the like can be appropriately prevented. Further, according to the production method of the present invention, a Ca-containing hydrated cured product having the above-mentioned excellent properties can be produced stably.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing one embodiment of a production method of the present invention in a state in which a processing container is longitudinally sectioned.
FIG. 2 is an explanatory view showing the principle of uniform distribution of water in continuous voids of a Ca-containing hydrated cured product in the method of the present invention.
FIG. 3 is an explanatory view showing another embodiment of the manufacturing method of the present invention in a state in which a processing container is longitudinally sectioned.
FIG. 4 is an explanatory view showing another embodiment of the manufacturing method of the present invention.
FIG. 5 is an explanatory view showing another embodiment of the manufacturing method of the present invention in a state where a processing container is longitudinally sectioned.
FIG. 6 is an explanatory view showing another embodiment of the manufacturing method of the present invention.
FIG. 7 is an explanatory view showing another embodiment of the manufacturing method of the present invention in a state in which a processing container is longitudinally sectioned.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing container, 2 ... Gas supply / exhaust part, 3 ... Gas supply / exhaust pipe, 4 ... Gas supply pipe system, 5 ... Suction pipe system, 6 ... Suction pump, 7 ... Exhaust pipe, 8, 9, 10 ... Open / close valve , 11, 11a wind box, 12 hole, 13 pipe, 14 gas supply pipe, 14a gas inlet, 15 seal, 100 body, 101 lid, 110 porous plate, A Ca Containing hydrated cured product, B: closed container, C: gas supply system, D: gas discharge system, E: container, F: gas discharge system

Claims (14)

An environment-friendly Ca-containing hydrated cured product having a calcium carbonate coating layer on at least the outer surface. 2. The environment-friendly Ca-containing hydrated cured product according to claim 1, wherein the cured product is a porous body having continuous voids therein, and further having a calcium carbonate coating layer on the inner surface of the continuous voids. 3. The environment-friendly Ca-containing hydrated hardened product according to claim 1 or 2, wherein the calcium carbonate coating layer is formed by carbonating the Ca-containing hydrated hardened product. The environment-friendly Ca-containing hydrated cured product according to claim 1, 2 or 3, which is a hydrated cured product cast in place. A hydrated hardened product or a cast-in-place hydrated hardened product which is immersed in water, used in contact with water, or used as a vegetation base. 4. The environmentally friendly Ca-containing hydrated cured product according to item 4. The Ca-containing hydrated hardened material in which water is adhered to at least the outer surface or at least the surface layer is impregnated with water is subjected to a carbonation treatment in a carbon dioxide gas atmosphere or a carbon dioxide-containing atmosphere, and is included in the Ca-containing hydrated hardened material surface layer A method for producing a hydrated, environmentally friendly, hydrated Ca-containing material, comprising forming a calcium carbonate coating layer on at least the outer surface of a hydrated, hydrated, Ca-containing product by carbonating uncarbonated Ca. The Ca-containing hydrated cured product has continuous voids inside, and carbonation of uncarbonated Ca contained in the inner surface layer of the continuous voids by carbonation treatment also forms a calcium carbonate coating layer on the inner surface of the continuous voids. The method for producing a hydrated, environmentally friendly Ca-containing hydrate according to claim 6, wherein the hydrated hydrated product is produced. After impregnating the Ca-containing hydrated cured product having continuous voids therein with water, a part of the water is discharged by depressurizing the inside of the Ca-containing hydrated cured product. By subjecting the cured product to a carbonation treatment in a carbon dioxide gas atmosphere or a carbon dioxide gas-containing atmosphere, and carbonizing uncarbonated Ca contained in the Ca-containing hydrated cured product surface layer and the inner surface layer of the continuous voids, Ca-containing water is obtained. The method for producing an environment-friendly Ca-containing hydrated cured product according to claim 7, wherein a calcium carbonate coating layer is formed on an outer surface of the cured product and on an inner surface of the continuous void. The environment-friendly Ca-containing hydration hardening according to claim 8, wherein in the step of depressurizing the inside of the Ca-containing hydration hardened body, the pressure inside the Ca-containing hydrated hardened body is reduced to 0.8 atm or less. How to make the body. In the step of carbonating the Ca-containing hydrated hardened product, the Ca-containing hydrated hardened product is placed in a closed container, and carbon dioxide gas or a carbon dioxide gas-containing gas is supplied into the closed container, so that the Ca-containing hydrated hardened product is hardened. The method for producing a hydrated environment-friendly Ca-containing hydrate according to claim 6, wherein the body is subjected to a carbonation treatment. The Ca-containing hydrated cured product has continuous voids therein, and in the step of carbonating the Ca-containing hydrated cured product, carbon dioxide gas or carbon The method for producing an environmentally friendly cured hydrated Ca-containing material according to claim 7, 8 or 9, wherein the hydrated Ca-containing cured product is carbonated by supplying a gas-containing gas. 12. The method for producing an environmentally-friendly Ca-containing hydrated hardened product according to claim 11, wherein carbon dioxide or a carbon dioxide-containing gas is supplied to the Ca-containing hydrated hardened product placed in the container through gas supply means. . The Ca-containing hydrated cured product has continuous voids therein, and has holes extending from the outer surface to the inside of the hydrated cured product. The environment-friendly Ca-containing hydrated cured product according to claim 7, 8 or 9, wherein the Ca-containing hydrated cured product is subjected to a carbonation treatment by supplying carbon dioxide or a carbon dioxide-containing gas to the mixture. Production method. The environment-friendly Ca-containing hydrated cured product according to claim 13, wherein carbon dioxide or a carbon dioxide-containing gas is supplied from a gas supply means into the holes of the Ca-containing hydrated cured product placed in the container. Manufacturing method.

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