JP2023034915A - Carbonation hardening flask for hydraulic fluidized material and hydraulic carbonated structure production method - Google Patents

Abstract

To provide a carbonation hardening flask for a hydraulic fluidized material capable of easily subjecting a hydraulic fluidized material to carbonation hardening without executing demolding in a short time, and a hydraulic carbonated structure production method.SOLUTION: A carbonation curing flask for a hydraulic fluidized material comprises: a flask member; and a flask-shaped gas permeation member provided at the inside of the flask member, capable of permeating a gas and capable of exposing the gas permeated through the inside to a hydraulic fluidized material that is stored inside.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mold for carbonation curing of a hydraulic fluidized material and a method for manufacturing a hydraulic carbonation structure.

Cement used in concrete emits a larger amount of carbon dioxide gas (carbon dioxide, CO ₂ ) than the decarboxylation of the raw material during production and the fuel during firing. In response to the growing interest in climate change control in recent years, it is required to significantly reduce the amount of carbon dioxide emitted during the production of concrete.

As one of the methods for reducing carbon dioxide emissions, mixed cement is widely used in which granulated blast furnace slag (hereinafter simply referred to as ground granulated blast furnace slag) is mixed with cement. However, if the amount of ground granulated blast furnace slag is increased, hardening is slowed down, the period until demolding becomes longer, and wet curing for a long time is required to obtain sufficient strength. For this reason, problems remain in terms of construction period and cost.

In addition, precast concrete is produced by hardening a concrete kneaded product obtained by adding γ-C ₂ S (γ-2CaO.SiO ₂ ; also called γ belite) to steelmaking slag powder and Portland cement, and then curing the concrete by carbonation. disclosed.

As a formwork for hardening the above hydraulic fluidized material, for example, Patent Document 1 describes a formwork composed of an outer formwork and an inner formwork.

However, with conventional molds such as those disclosed in Patent Document 1, carbonation curing of the hydraulic fluidized product is not easy, and a dedicated mold for carbonation curing of the hydraulic fluidized product is very expensive. . Further, conventionally, in order to carbonate a hydraulic fluidized material, it is necessary to carbonate the hydraulic structure after the hydraulic structure obtained by hardening the hydraulic fluidized material is removed from the formwork. Therefore, the process is complicated.

Japanese Patent Application Laid-Open No. 2004-034377

SUMMARY OF THE INVENTION An object of the present invention is to provide a carbonation-hardening formwork for a hydraulic fluidized material and a method for manufacturing a hydraulically carbonated structure, which can be carbonation-hardened in a short time and in a simple manner without demolding the hydraulic fluidized material. It is to be.

[1] A formwork member, and a formwork-like form that is provided inside the formwork member, is permeable to gas, and can expose the permeated gas to the hydraulic fluidized material stored inside. and a gas permeable member.
[2] The mold for carbonation hardening of the hydraulic fluidized material according to [1] above, wherein the gas permeable member has a porosity of 60% or more and 95% or less.
[3] The carbonation-hardening mold for a hydraulic fluidized product according to [1] or [2] above, wherein the gas permeable member is porous and has an average pore diameter of 80 μm or more and 700 μm or less. frame.
[4] The mold for carbonation hardening of the hydraulic fluidized material according to any one of [1] to [3] above, wherein the gas permeable member is a foamed material or a non-woven fabric.
[5] The formwork for carbonation hardening of hydraulic fluidized material according to any one of [1] to [4] above, wherein the formwork member has a mechanical strength greater than that of the gas permeable member.
[6] The mold for carbonation hardening of the hydraulic fluidized material according to any one of the above [1] to [5], wherein the hardness of the mold member is higher than that of the gas permeable member.
[7] The mold for carbonation hardening of the hydraulic fluidized material according to any one of [1] to [6], wherein the gas permeable member has a plurality of projections on the outer surface.
[8] The formwork for carbonation hardening of the hydraulic fluidized material according to any one of [1] to [7] above, wherein the formwork member has an opening at the top.
[9] A hammer for placing and storing the hydraulic fluidized material inside the gas permeable member in the carbonation hardening mold for the hydraulic fluidized material according to any one of the above [1] to [8]. and exposing the gas containing carbon dioxide permeated through the gas-permeable member to the hydraulic fluidized material while curing the hydraulic fluidized material stored in the gas-permeable member. A carbonation curing step of carbonating the fluidized material while curing to obtain a hydraulic carbonation structure.
[10] The method for producing a carbonated hydraulic structure according to [9] above, wherein in the carbonation curing step, the hydraulic fluidized material is carbonized within 5 days after casting the hydraulic fluidized material.
[11] The method for producing a carbonated hydraulic structure according to [9] above, wherein in the carbonation curing step, the hydraulic fluidized material is carbonized within two days after casting the hydraulic fluidized material.
[12] The method for producing a carbonated hydraulic structure according to [9] above, wherein in the carbonation hardening step, the hydraulic fluidized material is carbonized within one day after casting the hydraulic fluidized material.
[13] Manufacture of the hydraulic carbonation structure according to any one of the above [9] to [12], further comprising a demolding step of demolding the hydraulic carbonation structure from the gas permeable member. Method.

INDUSTRIAL APPLICABILITY According to the present invention, a carbonation-hardening mold for a hydraulic fluidized material and a method for manufacturing a hydraulic carbonation structure are provided, which are quick and easy, and which can carbonation-harden the hydraulic fluidized material without demolding. can do.

FIG. 1 is a perspective view showing an example of a mold for carbonation hardening of the hydraulic fluidized material of the embodiment. 2 is a cross-sectional view of FIG. 1. FIG. FIG. 3 is a cross-sectional view showing another example of the carbonation hardening mold for the hydraulic fluidized material of the embodiment. 4 is a digital camera image showing carbonation evaluation results of the hydraulic carbonation structure obtained in Example 1. FIG. 5 is a digital camera image showing carbonation evaluation results of the hydraulic carbonation structure obtained in Comparative Example 1. FIG.

A detailed description will be given below based on the embodiment.

As a result of intensive research, the present inventors have found that the gas permeable member is a gas permeable member that is provided inside the form member and stores the hydraulic fluidized material. The hydraulic fluidized material stored inside the member can be carbonized during curing, and as a result, the hydraulic fluidized material can be easily carbonated and hardened in a short time without demolding. The present invention has been completed.

The formwork for carbonation hardening of the hydraulic fluidized product of the present invention (hereinafter also simply referred to as the formwork for carbonation hardening) is provided inside the formwork member and the formwork member, and is permeable to gas. and a formwork-like gas permeable member (hereinafter also simply referred to as a gas permeable member) capable of exposing the gas that has permeated the inside to the hydraulic fluidized material stored inside.

FIG. 1 is a perspective view showing an example of a mold for carbonation hardening of the hydraulic fluidized material of the embodiment. 2 is a cross-sectional view of FIG. 1. FIG. 1 and 2 show a state in which the hydraulic fluidized material H is stored in the gas permeable member 20 of the carbonation curing mold 1. As shown in FIG. 1 and 2 and FIG. 3, which will be described later, the gas permeable pores in the gas permeable member 20 are omitted for convenience.

As shown in FIG. 1 , the carbonation curing mold 1 includes a mold member 10 and a mold-shaped gas permeable member 20 provided inside the mold member 10 . The carbonation hardening mold 1 is a mold for carbonation hardening of the hydraulic fluid H stored in the gas permeable member 20 . Carbonation hardening of the hydraulic fluidized material H means carbonation and hardening of the hydraulic fluidized material H.

A formwork member 10 constituting the carbonation curing formwork 1 supports a formwork-shaped gas permeable member 20 from the outside. For example, the formwork member 10 is a conventional existing formwork which is impermeable to gases and which hardens the hydraulic fluidize H. As shown in FIG. The form member 10 may be made of metal such as steel, wood, resin, or the like, or may be made of a combination thereof.

The gas permeable member 20 constituting the carbonation curing mold 1 is permeable to gas, and the gas permeates the interior of the gas permeable member 20 . The gas permeable member 20 is provided with a plurality of pores. The formation state of the plurality of pores is not particularly limited as long as the gas can permeate through the interior of the gas permeable member 20. The plurality of pores may be in communication with each other, or the plurality of pores may be in communication with each other. They may be independent without communicating with each other, or these states may be mixed.

Further, the gas permeable member 20 can expose the gas that has permeated through the inside of the gas permeable member 20 to the hydraulic fluidized material H that is stored inside I of the gas permeable member 20 . For example, as shown in FIG. 2 , the outer surface of the gas permeable member 20 is provided on the inner surface of the form member 10 . Further, for example, the hydraulic fluidized material H that is stored is in contact with the gas permeable member 20 . The inner surface of the formwork member 10 and the outer surface of the gas permeable member 20 may be fixed with an adhesive or the like.

Regarding the gas permeable member 20 that is permeable to gas, the walls and bottom of the gas permeable member 20 are permeable to gas along their in-plane and out-of-plane directions. If the atmosphere of the outside U contains carbon dioxide, the carbon dioxide enters the inside of the gas permeable member 20 from the outside U. The carbon dioxide that has entered the inside of the gas permeable member 20 permeates the walls and bottom of the gas permeable member 20 along the in-plane direction and the out-of-plane direction, and is stored inside the gas permeable member 20. Hydraulic fluidized material H is reached. Therefore, even if the gas permeable member 20 is supported from the outside by the gas-impermeable form member 10, the hydraulic fluidized material H stored inside the gas permeable member 20 can be carbonated. That is, the gas permeable member 20 is a carbon dioxide permeable member.

From the viewpoint of uniformly carbonating the hydraulic fluidized material H in a short time, as shown in FIGS. It is preferable to provide the gas permeable member 20 on the entire inner surface of the .

The lower limit of the porosity of the gas permeable member 20 is preferably 60% or more, more preferably 80% or more, and even more preferably 85% or more, and the upper limit is preferably 95% or less, more preferably 91% or less. When the porosity of the gas permeable member 20 is 60% or more, the hydraulic fluidized material H stored inside the gas permeable member 20 can be carbonated in a short period of time. If the porosity of the gas permeable member 20 is 95% or less, the decrease in strength of the gas permeable member 20 can be suppressed.

Also, the gas permeable member 20 is preferably porous. When the gas permeable member 20 is porous, the lower limit of the average pore diameter of the gas permeable member 20 is preferably 80 μm or more, more preferably 130 μm or more, still more preferably 150 μm or more, and the upper limit is preferably It is 700 μm or less, more preferably 300 μm or less. When the average pore diameter of the gas permeable member 20 is 80 μm or more, the hydraulic fluidized material H stored inside the gas permeable member 20 can be carbonated in a short period of time. When the average pore diameter of the gas permeable member 20 is 700 μm or less, the decrease in strength of the gas permeable member 20 can be suppressed.

From the viewpoint of uniformly carbonating and hardening the hydraulic fluidized material H in a short time, the gas permeable member 20 is preferably a foam material or a non-woven fabric. Among foamed materials, sponge is more preferable.

From the viewpoint of improving the moldability of the hydraulically carbonated structure, it is preferable that the mechanical strength of the form member 10 is greater than that of the gas permeable member 20 . Moreover, from the same point of view, it is preferable that the hardness of the form member 10 is greater than that of the gas permeable member 20 .

FIG. 3 is a cross-sectional view showing another example of the carbonation hardening mold for the hydraulic fluidized material of the embodiment. As shown in FIG. 3, the gas permeable member 20 preferably has a plurality of protrusions 21 on its outer surface. The outer surface of the gas permeable member 20 is the surface supported by the form member 10, and the inner surface of the gas permeable member 20 is the surface that contacts the hydraulic fluidized material H during storage. When the plurality of projections 21 are provided on the outer surface of the gas permeable member 20, preferably on the entire outer surface of the gas permeable member 20, even if the mechanical strength and hardness of the gas permeable member 20 are very small, the hydraulic carbonation structure can be obtained. Good moldability.

FIG. 3 shows an example in which only the plurality of protrusions 21 are in contact with the inner surface of the formwork member 10 and a gap exists between the gas permeable member 20 and the formwork member 10. The portion 21 may be recessed from the distal end side to the proximal end side, and the gas permeable member 20 and the formwork member 10 may contact each other without a gap.

Moreover, as shown in FIG. 1, the form member 10 preferably has an opening 11 at the top. From the opening 11 of the formwork member 10 , the hydraulic fluidized material H can be poured into the inner side I of the gas permeable member 20 . Also, the cured state of the hydraulic fluidized material H can be easily confirmed visually from the opening 11 .

Instead of the opening 11 , a cover (not shown) that can be attached to and removed from the formwork member 10 or that can be opened and closed may be provided on the upper part of the formwork member 10 . In this case, it is preferable to provide a gas-permeable member inside the formwork member that constitutes the lid portion (not shown) in the same manner as described above. Further, the formwork member forming the lid portion may be provided with a through-hole that allows the outside U and the inside I to communicate with each other and allows gas to enter.

The hydraulic fluidized material H stored in the gas permeable member 20 of the carbonation curing mold 1 can be carbonated, that is, it can fix carbon dioxide inside after curing. Preferred types of the hydraulic fluidized material H are concrete and mortar. From the viewpoint of good carbonation, the hydraulic fluidized material H contains, as carbonation components, a group consisting of γ-C ₂ S, ordinary Portland cement, slaked lime, granulated blast furnace slag, expansive agent, and fly ash. It preferably contains one or more selected substances.

Carbon dioxide sources used for carbonation of the hydraulic fluidized material H include carbon dioxide cylinders, separated and recovered carbon dioxide, exhaust gas from thermal power plants, exhaust gas from boilers, and other product manufacturing processes. Various exhaust gases are preferred, such as exhaust gases containing carbon dioxide. Alternatively, after adjusting the humidity and temperature of the exhaust gas, the adjusted exhaust gas may be used as the carbon dioxide source.

As described above, the carbonation hardening mold 1 includes a mold member 10 and a mold-shaped gas permeable member through which gas can permeate and in which the hydraulic fluidized material H is placed and stored. 20. The gas permeable member 20 can expose the hydraulic fluidized material H to the carbon dioxide that enters from the outside U and is discharged to the inside I while retaining the hydraulic fluidized material H. Therefore, the carbonation hardening mold 1 can carbonation harden the hydraulic fluid H inside the gas permeable member 20 . In this way, the mold 1 for carbonation curing does not require demolding work, and carbonation curing can be easily performed in a short time.

In addition, compared to the hydraulic structure obtained by hardening the hydraulic fluidized material H, the hydraulic fluidized material H allows a large amount of gas to enter the entire interior in a short time. Therefore, the carbonation curing mold 1 can uniformly carbonate the hydraulic fluid H throughout the entire interior in a short time compared to the conventional carbonation curing mold.

On the other hand, conventionally, a hydraulic structure is produced by curing the hydraulic fluidized material H placed in a formwork, and after the hydraulic structure is removed from the formwork, the hydraulic structure is carbonated. . Therefore, complicated work is required to demold the hydraulic structure. Further, conventionally, instead of carbonating the hydraulic fluidized material before hardening as in the present invention, the hydraulic structure after hardening is carbonated. Unlike the hydraulic fluidized material H, in the hydraulic structure, carbon dioxide penetrates only to a shallow depth from the surface, and the penetration time is slow. Therefore, even if the hydraulic structure is carbonized, the inside is not carbonized, carbonation occurs only from the surface to a shallow depth, and the carbonation takes a long time.

Next, the method for producing the hydraulic carbonation structure of the present invention will be described. In the method for manufacturing a hydraulic carbonation structure of the present invention, the carbonation curing mold 1 described above is used. Specifically, the manufacturing method of the hydraulic carbonation structure has a casting step and a carbonation curing step.

In the placing step, the hydraulic fluidized material H is placed and stored in the inside I of the gas permeable member 20 of the carbonation curing mold 1 . The hydraulic fluidized material H is driven into the gas permeable member 20 from the opening 11, for example.

In the carbonation hardening step performed after the placing step, the gas containing carbon dioxide permeated through the gas permeable member 20 is hydraulically flowed while curing the hydraulic fluidized material H stored in the gas permeable member 20. exposing to the compound H and carbonating the hydraulic fluidized compound H while hardening to obtain a hydraulically carbonated structure. In this way, in a state where the hydraulic fluidized material H is stored in the gas permeable member 20, the carbonation hardening mold 1 is exposed to the carbonic acid environment, so that the carbonation hardening mold 1 is exposed to the water by the gas permeable member 20. The hard fluidized material H can be carbonation hardened.

The timing of carbonation and curing can be appropriately selected depending on the degree of carbonation, the desired properties of the hydraulic carbonation structure, etc. Carbonation may be performed before curing or after curing. or during curing. Among them, in the carbonation hardening step, when the hydraulic fluidized material H is placed, preferably within 5 days, more preferably within 2 days, and further preferably within 1 day, carbonation of the hydraulic fluidized material H is carried out. , the hydraulic fluidized material H can be uniformly carbonated.

Moreover, the method for producing a hydraulically carbonated structure of the present invention may further include a demolding step. The demolding step is performed after the carbonation curing step. In the demolding step, the hydraulic carbonation structure is demolded from the gas permeable member 20 . Moreover, the hydraulic carbonation structure demolded from the gas permeable member 20 may be subjected to a heat treatment, if necessary.

Although the embodiments have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept and claims of the present disclosure, and can be variously modified within the scope of the present disclosure. be able to.

EXAMPLES Next, examples and comparative examples will be described, but the present invention is not limited to these examples.

(Example 1)
First, a hydraulic fluidized material was prepared. Specifically, 175 kg/m ³ of tap water, 105 kg/m ³ of ordinary portland cement, 140 kg/m ³ of granulated blast furnace slag, 105 kg/m ³ of belite gamma type, 733 kg/m ³ of crushed sand, and 1015 kg/m ³ of crushed stone. The mixture was kneaded with a concrete mixer to obtain a hydraulic fluidized material.

Subsequently, the hydraulic fluidized material was placed in a mold for carbonation curing without a lid as shown in FIG. As the mold for carbonation curing, the mold member was made of steel, and the gas permeable member was sponge having a plurality of projections on its outer surface.

Immediately after placing the hydraulic fluidized material, the hydraulic fluidized material was carbonized and hardened. Carbonation conditions were a temperature of 20° C., a carbon dioxide concentration of 80%, and 7 days. A hydraulically carbonated structure was obtained by carbonating and hardening the hydraulic fluidized material under these conditions.

(Comparative example 1)
A hydraulic carbonation structure was obtained in the same manner as in Example 1, except that no gas permeable member was provided.

[evaluation]
Carbonation was evaluated for the hydraulic carbonation structures obtained in the above examples and comparative examples. Specifically, the hydraulic carbonation structure was cut to obtain a cross section, and the phenolphthalein reagent was sprayed on the cross section of the hydraulic carbonation structure. Subsequently, the section sprayed with the phenolphthalein reagent was observed with a digital camera image. In the digital camera image, dark portions (red portions) are portions where alkalinity is maintained without being carbonated, and light portions are portions which are carbonated.

4 is a digital camera image showing carbonation evaluation results of the hydraulic carbonation structure obtained in Example 1. FIG. 5 is a digital camera image showing carbonation evaluation results of the hydraulic carbonation structure obtained in Comparative Example 1. FIG. The upper side of FIGS. 4 and 5 is the side of the opening of the form member.

As shown in FIG. 4, in the hydraulic carbonation structure obtained in Example 1, uniform carbonation was confirmed from the surface to a predetermined depth over the entire circumference of the cross section. For this reason, the carbon dioxide that has entered the gas permeable member uniformly reaches the entire surface of the hydraulic fluidized material stored inside the gas permeable member in a short time, and then the carbon dioxide is released into the hydraulic fluidized material. It was suggested that it reacted with the fluidized material.

On the other hand, as shown in FIG. 5, in the hydraulic carbonation structure obtained in Comparative Example 1, carbonation was confirmed only in the upper part of the hydraulic carbonation structure, which is the opening side of the form member. For this reason, since the gas permeable member was not used in Comparative Example 1, the carbon dioxide that entered from the opening of the formwork member spreads over the entire surface of the hydraulic fluidized material stored inside the formwork member. It was suggested that carbon dioxide reached only the upper part of the opening side without reaching, and then carbon dioxide reacted only with the upper part of the hydraulic fluidized material.

1 Formwork for carbonation hardening of hydraulic fluidized material (formwork for carbonation hardening)
REFERENCE SIGNS LIST 10 form member 11 opening 20 gas permeable member 21 convex portion H hydraulic fluidized material U outside I inside

Claims (13)

a formwork member;
a formwork-like gas permeable member that is provided inside the formwork member, is permeable to gas, and can expose the gas that has permeated the interior to the hydraulic fluidized material stored inside; Formwork for carbonation hardening of hydraulic fluids. 2. The mold for carbonation hardening of hydraulic fluidized material according to claim 1, wherein said gas permeable member has a porosity of 60% or more and 95% or less. 3. The mold for carbonation hardening of hydraulic fluidized material according to claim 1, wherein said gas permeable member is porous and has an average pore diameter of 80 [mu]m or more and 700 [mu]m or less. The mold for carbonation curing of a hydraulic fluidized product according to any one of claims 1 to 3, wherein the gas permeable member is a foamed material or a non-woven fabric. 5. The mold for carbonation hardening of the hydraulic fluidized material according to claim 1, wherein the mechanical strength of the mold member is greater than that of the gas permeable member. The mold for carbonation hardening of hydraulic fluidized material according to any one of claims 1 to 5, wherein the hardness of the mold member is higher than that of the gas permeable member. The mold for carbonation hardening of hydraulic fluidized material according to any one of claims 1 to 6, wherein said gas permeable member has a plurality of protrusions on its outer surface. The formwork for carbonation hardening of hydraulic fluidized material according to any one of claims 1 to 7, wherein said formwork member has an opening at the top. A placing step of placing and storing the hydraulic fluidized material inside the gas permeable member in the carbonation hardening mold for the hydraulic fluidized material according to any one of claims 1 to 8;
While curing the hydraulic fluidized material stored in the gas permeable member, the gas containing carbon dioxide permeated through the gas permeable member is exposed to the hydraulic fluidized material to harden the hydraulic fluidized material. and a carbonation curing step of carbonating to obtain a hydraulic carbonation structure. 10. The method for producing a hydraulically carbonated structure according to claim 9, wherein in the carbonation hardening step, the hydraulic fluidized material is carbonized within 5 days after casting the hydraulic fluidized material. 10. The method for producing a carbonated hydraulic structure according to claim 9, wherein in the carbonation hardening step, the hydraulic fluidized material is carbonized within two days after casting the hydraulic fluidized material. 10. The method for producing a hydraulically carbonated structure according to claim 9, wherein in the carbonation hardening step, the hydraulic fluidized material is carbonized within one day after casting the hydraulic fluidized material. The method for producing a hydraulically carbonated structure according to any one of claims 9 to 12, further comprising a demolding step of demolding the hydraulically carbonated structure from the gas permeable member.

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