Concrete structure and method for manufacturing a concrete structure

Abstract

The present invention provides a conductive concrete structure that does not require a carbon nanoparticle dispersant, has low dependence on the formulation, is relatively easy to manufacture, and is versatile. [Solution] The concrete structure 1 includes coarse aggregate 2 and mortar 3 filling the gaps between the coarse aggregate 2, the coarse aggregate 2 is covered with a carbon film 4, and each piece of coarse aggregate 2 is in direct contact with at least one other piece of coarse aggregate 2 in the surrounding area.

Description

Technical Field

[0001] The present invention relates to a conductive concrete structure and a method for manufacturing the same.

Background Art

[0002] In recent years, research has been conducted on technology for storing electricity in concrete (see, for example, Patent Document 1). Patent Document 1 discloses a conductive cement composite, a conductive mortar, and a conductive concrete including a continuous penetration network of a hydraulic cement, water, a carbon nanoparticle dispersant, and nanoporous carbon nanoparticles. The "continuous penetration network of nanoporous carbon nanoparticles" is a network formed by a continuous connection of carbon nanoparticles that have penetrated into the capillary pore network of cement to a sufficient extent to make the cement composite conductive. In these conductive cement composites, conductive mortars, and conductive concretes, conductivity is exhibited by the continuous penetration network of nanoporous carbon nanoparticles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the electricity-storing concrete described in Patent Document 1, for example, a carbon nanoparticle dispersant is required, and the composite in the prior art has a high dependence on the formulation and is difficult to manufacture.

[0005] In view of the above background, an object of the present invention is to provide a conductive concrete structure that does not require a carbon nanoparticle dispersant, has a low dependence on the formulation, and is relatively easy to manufacture and has versatility, and a method for manufacturing the same.

Means for Solving the Problems

[0006] To solve the above problems, one aspect of the present invention provides a concrete structure (1) comprising coarse aggregate (2) and mortar (3) filling the gaps between the coarse aggregate, wherein the coarse aggregate is covered with a carbon film (4) and each piece of coarse aggregate is in direct contact with at least one other surrounding piece of coarse aggregate.

[0007] According to this embodiment, the carbon coating covering the coarse aggregate is conductive and forms continuous conductive paths, thereby ensuring the conductivity of the concrete structure. In this way, since a carbon nanoparticle dispersant is not required for the formation of conductive paths, a conductive concrete structure is provided that is less dependent on the mix design, relatively easy to manufacture, and versatile.

[0008] In the above embodiment, it is preferable that carbon fine particles are added to the mortar.

[0009] According to this embodiment, the continuity (i.e., conductivity) of the carbon coating covering the coarse aggregate is more reliably maintained. Furthermore, the amount of energy stored in the concrete structure can be increased by making the carbon fine particles in the mortar function as energy storage elements.

[0010] In the above embodiment, the concrete structure is preferably used for the building's frame.

[0011] According to this embodiment, the building's structure can be used as an energy storage body. Therefore, there is no need to manufacture a concrete structure specifically for energy storage, and the material can be used effectively.

[0012] Furthermore, in order to solve the above problems, another aspect of the present invention is a method for manufacturing a concrete structure (1), comprising the steps of: preparing coarse aggregate (2) (ST1); laying the coarse aggregate in a structure manufacturing space (6) (ST2); preparing mortar (3) to be filled in the gaps between the coarse aggregate (ST3); and pouring the mortar into the structure manufacturing space on which the coarse aggregate has been laid (ST4), wherein the step of preparing the coarse aggregate includes the step of coating the coarse aggregate with a carbon film (4).

[0013] In this embodiment, since the coarse aggregate is coated with a carbon film, the carbon films come into contact with each other when the coarse aggregate is laid in the structure manufacturing space. As a result, the carbon films are continuous, forming conductive paths in the concrete structure that constitutes the energy-storing concrete. In this way, since a carbon nanoparticle dispersant is not required for the formation of conductive paths, a conductive concrete structure with low dependence on the mix design and general applicability can be manufactured relatively easily.

[0014] In the above embodiment, a pair of electrodes (5) are placed inside the formwork (7) that defines the structure manufacturing space, and the coarse aggregate is laid in the structure manufacturing space so as to come into contact with the pair of electrodes.

[0015] According to this embodiment, the coarse aggregate can be reliably brought into contact with a pair of electrodes.

[0016] In the above embodiment, the step of preparing the mortar may include the step of adding carbon fine particles.

[0017] According to this embodiment, the continuity (conductivity) of the carbon coating covering the coarse aggregate is more reliably maintained during the mortar placement process. Furthermore, the amount of energy stored in the concrete structure can be increased by allowing the carbon microparticles in the mortar to function as energy storage elements.

[0018] In the above aspect, the method for manufacturing the concrete structure (1) preferably further includes a step (ST5) of vibrating and compacting the uncured concrete in the structure manufacturing space after placing the mortar added with the carbon microparticles.

[0019] According to this aspect, the mortar can be hermetically filled in the gaps between the coarse aggregates, and it is possible to prevent air from remaining in the gaps between the coarse aggregates.

Advantages of the Invention

[0020] According to the above aspects, it is possible to provide a concrete structure and a method for manufacturing the same that can achieve both ensuring the power storage amount and ensuring the concrete strength.

Brief Description of the Drawings

[0021] [Figure 1] A diagram schematically showing a concrete structure according to an embodiment [Figure 2] A flowchart showing a method for manufacturing a concrete structure according to an embodiment [Figure 3] A diagram showing the manufacturing procedure of a concrete structure according to an embodiment [Figure 4] A schematic diagram showing the usage state of a concrete structure according to an embodiment

Modes for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0023] FIG. 1 is a diagram schematically showing a concrete structure 1 according to an embodiment. As shown in FIG. 1, the concrete structure 1 includes coarse aggregates 2 and mortar 3, and has become a solid structure due to the hardening of the cement in the mortar 3. The mortar 3 is mainly composed of fine aggregates, cement, and water. The mortar 3 may contain an admixture amount.

[0024] Here, coarse aggregate 2 generally refers to aggregates that are larger than 5 mm, and fine aggregate generally refers to aggregates that are smaller than 5 mm. Fine aggregate and coarse aggregate 2 may be those specified in JIS A5005 "Crushed stone and crushed sand for concrete". The definitions of fine aggregate and coarse aggregate 2 are as described in JIS A0203 "Concrete Terminology". According to that definition, fine aggregate is aggregate that passes completely through a 10 mm sieve and passes through a 5 mm sieve at least 85 percent by weight, and coarse aggregate 2 is aggregate that remains on a 5 mm sieve at least 85 percent.

[0025] The definition of mortar 3 may be as described in JIS A0203 "Concrete Terminology." According to that definition, mortar 3 is a mixture of cement, water, fine aggregate, and admixtures added as needed, which are mixed by kneading or other methods, or hardened. However, mortar 3 in this specification does not necessarily have to contain fine aggregate. That is, mortar 3 in this specification may contain cement paste as defined in JIS A0203.

[0026] Concrete structure 1 is a structure used in the frame of a building. The frame may include the building's foundation, columns, beams, walls, floors, and diagonal braces. Concrete structure 1 is reinforced concrete and contains reinforcing bars (not shown) inside. In other embodiments, concrete structure 1 may be unreinforced concrete, fiber-reinforced concrete, steel-reinforced concrete, prestressed concrete, etc.

[0027] Each coarse aggregate 2 is in direct contact with at least one other coarse aggregate 2 in the surrounding area. Here, each coarse aggregate 2 does not have to be all of the coarse aggregate 2 in the concrete structure 1. For example, it is sufficient if the coarse aggregate 2 in direct contact with at least one other coarse aggregate 2 in the surrounding area accounts for 85% or more by weight of the total coarse aggregate 2, and it is even better if it accounts for 90% or more by weight. Many coarse aggregates 2 are in contact with multiple other coarse aggregates 2 in the surrounding area (for example, coarse aggregates 2 above and below).

[0028] Each coarse aggregate 2 is coated with a carbon film 4. Therefore, the carbon film 4 of each coarse aggregate 2 is in direct contact with the carbon film 4 of at least one other surrounding coarse aggregate 2. In this embodiment, the carbon film 4 is made of nanocarbon. Here, nanocarbon is a carbon cluster having a structure of nanometer size (1 nanometer to 100 nanometers). Nanocarbon may take the form of, for example, carbon nanotubes (CNTs), graphene, fullerenes, carbon nanohorns, graphene nanoribbons, or encapsulated CNTs, and is even better if it is at least one selected from fullerenes, carbon nanotubes, and graphene. Carbon nanotubes (CNTs) may be single-walled CNTs in which one carbon film (graphene sheet) is wound cylindrically, double-walled CNTs in which two graphene sheets are wound concentrically, or multi-walled CNTs in which multiple graphene sheets are wound concentrically. In other embodiments, the carbon coating 4 may consist of carbon clusters (carbon nanoparticles other than nanocarbons) with a size of 100 nanometers or larger.

[0029] The carbon film 4 is formed on the outer surface of the coarse aggregate 2 by applying a coating agent containing nanocarbons. The nanocarbon coating agent is formed by adding nanocarbons to a suitable volatile liquid. The nanocarbons are evenly dispersed in the liquid. After application to the outer surface of the coarse aggregate 2, the liquid coating agent vaporizes, forming a conductive carbon film 4 made of nanocarbons that covers the coarse aggregate 2.

[0030] Mortar 3 contains carbon nanoparticles. The carbon nanoparticles may be in the form of carbon nanotubes (CNTs), graphene, fullerenes, carbon nanohorns, graphene nanoribbons, encapsulated CNTs, etc., and may be at least one selected from fullerenes, carbon nanotubes, and graphene. The carbon nanoparticles added to Mortar 3 may be carbon clusters (nanocarbons) having a structure of nanometer size (1 nanometer to 100 nanometers), and may also be carbon clusters of 100 nanometers or larger.

[0031] A pair of electrodes 5 are provided on the concrete structure 1. The pair of electrodes 5 are positioned opposite each other on the concrete structure 1, and are in contact with the concrete structure 1. More specifically, the pair of electrodes 5 are in contact with the coarse aggregate 2 and mortar 3 of the concrete structure 1. The electrodes 5 do not need to be provided over the entire end face of the concrete structure 1 as shown in the figure, but may be provided on only a part of the end face. The electrodes 5 may be provided on the end face of the concrete structure 1 as shown in the figure, or they may be provided inside the concrete structure 1. The electrodes 5 may be made of any conductive material. The electrodes 5 may be in the shape of a flat plate or a rod. When the electrodes 5 are provided inside the concrete structure 1, metal reinforcing bars or reinforcing bars containing carbon fibers may be used as electrodes 5.

[0032] Since each coarse aggregate 2 is in direct contact with other coarse aggregates 2, the carbon coating 4 of each coarse aggregate 2 is continuous with a pair of electrodes 5. The concrete structure 1 is configured as an energy storage body that stores electricity in the carbon coating 4 when a charging voltage is applied to the pair of electrodes 5. That is, the concrete structure 1 functions as energy-storing concrete. The configuration of the energy-storing concrete may be any. The energy-storing concrete may have, for example, the configuration described in Non-Patent Document 1. The concrete structure 1 releases the electricity stored in the carbon coating 4 when the voltage between the pair of electrodes 5 is low. During charging and discharging of the concrete structure 1, the carbon coating 4 forms the main conductive path. The carbon particles in the mortar 3 function as energy storage bodies that store electricity similarly to the carbon coating 4, and also form auxiliary conductive paths.

[0033] Thus, the concrete structure 1 of this embodiment includes coarse aggregate 2 and mortar 3, the coarse aggregate 2 is covered with a carbon film 4, and each piece of coarse aggregate 2 is in direct contact with at least one other piece of coarse aggregate 2 in the surrounding area. Therefore, the carbon film 4 covering the coarse aggregate 2 forms a continuous conductive path. This ensures the conductivity of the concrete structure 1.

[0034] Thus, since a carbon nanoparticle dispersant is not required for the formation of conductive paths, a conductive concrete structure 1 is provided that is less dependent on the formulation, relatively easy to manufacture, and versatile.

[0035] In this embodiment, carbon nanoparticles are added to the mortar 3. Therefore, the continuity (i.e., conductivity) of the carbon film 4 covering the coarse aggregate 2 is more reliably maintained. In addition, the amount of energy stored in the concrete structure 1 can be increased by making the carbon nanoparticles in the mortar 3 function as energy storage bodies.

[0036] In this embodiment, since the concrete structure 1 is used as the building's frame, the building's frame can be used as an energy storage device. Therefore, there is no need to manufacture a concrete structure 1 specifically for energy storage, and the material can be used effectively.

[0037] Next, the method for manufacturing the concrete structure 1 will be described. Figure 2 is a flowchart showing the method for manufacturing the concrete structure 1 according to the embodiment, and Figure 3 is a diagram showing the manufacturing procedure for the concrete structure 1 according to the embodiment. The concrete structure 1 is manufactured by the manufacturer performing the following tasks. The manufacturer may be a worker performing the tasks, or it may be an automated machine that performs the specified tasks.

[0038] First, the manufacturer prepares the coarse aggregate 2 to be used in the manufacture of the concrete structure 1 (Step ST1). At this time, the manufacturer coats the coarse aggregate 2 with a carbon film 4. Specifically, the manufacturer applies a coating agent containing nanocarbon to the surface of all the coarse aggregate 2. After application to the outer surface of the coarse aggregate 2, the liquid coating agent vaporizes, forming a conductive carbon film 4 on the surface of the coarse aggregate 2 so as to cover it.

[0039] Next, the manufacturer lays coarse aggregate 2 in the structure manufacturing space 6 (see Figure 3(A)) for manufacturing the concrete structure 1 (step ST2). The structure manufacturing space 6 is the space within the formwork 7 as shown in Figure 3(A), and the coarse aggregate 2 is arranged in this space as shown in Figure 3(B), with gaps formed around each piece of coarse aggregate 2. A pair of electrodes 5 made of active material are pre-positioned within the formwork 7 so as to face each other across the structure manufacturing space 6. Each piece of coarse aggregate 2 is in contact with the surrounding coarse aggregate 2. In addition, coarse aggregate 2 placed near an electrode 5 is in contact with the corresponding electrode 5 and also with the surrounding coarse aggregate 2. This forms the main conductive path of the carbon coating 4.

[0040] The manufacturer also prepares mortar 3 to be used in the manufacture of the concrete structure 1, that is, mortar 3 to be filled into the gaps of the coarse aggregate 2 (step ST3). At this time, the manufacturer thoroughly mixes cement, sand (fine aggregate), carbon particles and water so that each material is evenly dispersed. Step ST3 is typically performed after the process of laying the coarse aggregate 2 in step ST2. However, step ST3 may be performed in parallel with step ST2, or before step ST2.

[0041] After steps ST2 and ST3, the manufacturer pours mortar 3 into the structure manufacturing space 6 where the coarse aggregate 2 is laid (step ST4). As shown in Figure 3(C), the mortar 3 fills the gaps between the coarse aggregate 2 and between the coarse aggregate 2 and the electrode 5.

[0042] In this embodiment, the manufacturer compacts the mortar 3, i.e., the unhardened concrete, in parallel with the mortar placement process in step ST4 (step ST5). Compaction of the mortar 3 is preferably performed using a vibrator (not shown) attached to the formwork 7. The vibrator may be a fixed type fixed to the formwork 7, or it may be a portable type inserted into the structure manufacturing space 6 on which the coarse aggregate 2 is laid.

[0043] After the mortar 3 has hardened to the required strength, the manufacturer demolds it, i.e., removes the formwork 7 from the concrete structure 1 (step ST6). This completes the production of the concrete structure 1. The concrete structure 1 is produced by prepacked concrete, in which coarse aggregate 2 is placed at the construction site and then mortar 3 is filled into the gaps between the coarse aggregate 2.

[0044] Thus, the method for manufacturing the concrete structure 1 comprises the steps of preparing coarse aggregate 2 (step ST1), laying the coarse aggregate 2 in the structure manufacturing space 6 (step ST2), preparing mortar 3 (step ST3), and pouring the mortar 3 into the structure manufacturing space 6 between the coarse aggregates 2 (step ST4). The step of preparing the coarse aggregate 2 in step ST1 includes the step of coating the coarse aggregate 2 with a carbon film 4. Because the coarse aggregate 2 is coated with a carbon film 4, the carbon films 4 come into contact with each other when the coarse aggregate 2 is laid in the structure manufacturing space 6. As a result, the carbon films 4 are continuous, forming conductive paths in the concrete structure 1 that constitute the energy-storing concrete. In this way, since a carbon nanoparticle dispersant is not required for the formation of conductive paths, a conductive concrete structure 1 with low dependence on the mix and generality can be manufactured relatively easily.

[0045] In step ST2, a pair of electrodes 5 are placed inside the formwork 7 that defines the structural manufacturing space 6, and the coarse aggregate 2 is laid in the structural manufacturing space 6 so as to come into contact with the pair of electrodes 5. As a result, the coarse aggregate 2 is reliably in contact with the pair of electrodes 5, and the conductivity of both electrodes 5 is ensured.

[0046] In this embodiment, the step ST1 for preparing the mortar 3 includes the step of adding carbon fine particles. Therefore, in the step ST4 for pouring the mortar 3, the continuity (conductivity) of the carbon coating 4 covering the coarse aggregate 2 is more reliably maintained. Furthermore, by making the carbon fine particles in the mortar 3 function as energy storage bodies, the amount of energy stored in the concrete structure 1 can also be increased.

[0047] The manufacturing method for the concrete structure 1 of this embodiment further includes a step (step ST5) in which, after pouring mortar 3 to which carbon fine particles are added, vibrations are applied to compact the unhardened concrete in the structure manufacturing space 6. As a result, the mortar 3 is airtightly filled into the gaps of the coarse aggregate 2, and the retention of air in the gaps of the coarse aggregate 2 is suppressed.

[0048] Figure 4 is a schematic diagram showing the usage state of the concrete structure 1 according to the embodiment. As shown in Figure 4(A), in the initial period after manufacturing, the manufactured concrete structure 1 does not contain cations or anions. In other words, the concrete structure 1 does not retain positive or negative charges, and its charge amount is zero.

[0049] As shown in Figure 4(B), during charging, when a power supply 8 is connected to a pair of electrodes 5 and a voltage is applied, electrons or negative ions accumulate on the positive electrode 5 side, and positive ions accumulate on the negative electrode 5 side. The pair of electrodes 5 are current collectors, with the portion of the concrete structure 1 near the positive electrode 5 forming the positive electrode layer, and the portion of the concrete structure 1 near the negative electrode 5 forming the negative electrode layer. The concrete structure 1 holds positive and negative charges in the positive and negative electrode layers, and enters an energy storage state where electricity is stored.

[0050] A potential difference exists between the pair of electrodes 5 of the concrete structure 1. As shown in Figure 4(C), when an electrical device 9 is connected to both electrodes 5 during discharge, the concrete structure 1 discharges, and electricity flows to the electrical device 9. When the concrete structure 1 discharges, its stored energy decreases. When voltage is applied to the pair of electrodes 5 again, as shown in Figure 4(B), the concrete structure 1 is recharged, and its stored energy increases.

[0051] For charging the concrete structure 1, it is preferable to use electricity from renewable energy sources such as solar power, wind power, and geothermal power, or off-peak electricity. This makes it possible to conserve energy by using the concrete structure 1 as an energy storage device. The electricity stored in the concrete structure 1 can be used as the building's daily power supply or emergency power supply. In addition, the electricity stored in the concrete structure 1 can be used as an energy source for streetlights and traffic signals at night, or as an emergency power supply during disasters.

[0052] Concrete structure 1 may be, for example, a building structure such as a foundation, column, beam, or slab, or a civil engineering structure such as concrete pavement, bridge pier, bridge abutment, bridge (concrete girder), dam or breakwater body, retaining wall, or tunnel. Furthermore, concrete structure 1 may be constructed on-site or manufactured in a yard or factory near the site.

[0053] This concludes the description of specific embodiments. However, the present invention is not limited to the above embodiments or modifications and can be broadly modified and implemented. For example, the specific configuration, arrangement, quantity, and materials of each member or part, as well as the specific operations and order of each operation, can be changed as appropriate, as long as they do not depart from the spirit of the present invention. Furthermore, not all of the components shown in the above embodiments are necessarily required and can be selected as appropriate. [Explanation of Symbols]

[0054] 1: Concrete structure 2: Coarse aggregate 3: Mortar 4: Carbon coating 5: Electrode 6: Structural manufacturing space 7: Formwork 8: Power supply 9: Electrical equipment

Claims

1. A concrete structure, It comprises coarse aggregate and mortar filling the gaps between the coarse aggregate, A concrete structure in which the coarse aggregate is coated with a carbon film, and each piece of coarse aggregate is in direct contact with at least one other piece of surrounding coarse aggregate.

2. The concrete structure according to claim 1, wherein carbon fine particles are added to the mortar.

3. A concrete structure according to claim 1 or 2, used in the frame of a building.

4. The process of preparing coarse aggregate, The process of laying the aforementioned coarse aggregate in the structure manufacturing space, A step of preparing mortar to be filled into the gaps of the aforementioned coarse aggregate, The process includes pouring the mortar into the structure manufacturing space on which the coarse aggregate has been laid, A method for manufacturing a concrete structure, wherein the step of preparing the coarse aggregate includes the step of coating the coarse aggregate with a carbon film.

5. A method for manufacturing a concrete structure according to claim 4, wherein a pair of electrodes are placed inside a formwork that defines the structure manufacturing space, and the coarse aggregate is laid in the structure manufacturing space so as to be in contact with the pair of electrodes.

6. The method for manufacturing a concrete structure according to claim 4 or 5, wherein the step of preparing the mortar includes the step of adding carbon fine particles.

7. A method for manufacturing a concrete structure according to claim 4 or 5, further comprising the step of applying vibration to the unhardened concrete in the structure manufacturing space after pouring the mortar.

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