Concrete structure treatment method and concrete structure treatment system

Abstract

To provide a method for treating a concrete structure and a system for treating the concrete structure, capable of more efficiently removing an alkaline component from the concrete structure after placing, and reducing the emission of ammonia.SOLUTION: A method for treating a concrete structure 1 is a method for treating the concrete structure 1 after placing, and wetting treatment for wetting the surface of the concrete structure 1 with treatment water in which carbon dioxide is dissolved is performed. A treatment system 10 for the concrete structure 1 is a treatment system 10 for the concrete structure 1 after placing. The treatment system 10 includes a mixing device 20 and a wetting treatment device 30. The mixing device 20 dissolves carbon dioxide in water to produce treated water. The wetting treatment device 30 wets the surface of the concrete structure 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for treating a concrete structure and a system for treating a concrete structure. [Background technology]

[0002] A particular problem for newly constructed art galleries, museums, and archives is the issue of alkaline substances generated from the concrete structure, which can cause deterioration or alteration of artworks, including paintings and paper, as well as public documents.

[0003] In the semiconductor industry, with the increasing integration of LSIs, there is a demand for higher levels of cleanliness in clean rooms at production facilities, and there is an urgent need to establish technology to suppress and remove chemical substances other than dust. In particular, alkaline components have a negative effect on circuit boards, so their reliable removal is required. One of the main sources of such alkaline components is thought to be structural concrete, which occupies a large volume of the plant.

[0004] Regarding problems caused by alkaline components generated from concrete structures, in buildings such as art galleries and museums where the amount of ammonia must be less than a certain value (20-30 ppb), the buildings are left to stand for about one year after completion, a long period known as the "concrete aging period," during which harmful substances such as alkaline components are removed using mechanical ventilation, dehumidification, and expensive air purifiers with gas adsorption filters to adsorb chemical substances. Such conventional methods require a long period of standing (concrete aging period) after completion of the building, which causes a problem of delays in the use of the building.

[0005] In order to quickly remove the alkaline components generated from such concrete structures, a method has been proposed in which the surface of a concrete structure is wetted with water and then dried (Patent Document 1).In addition, a method has been proposed in which the surface of a concrete structure is wetted with treated water containing fine bubbles and then dried, and a method has been proposed in which the surface of the concrete structure is wetted with treated water containing a surfactant and then dried (Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-8614 A [Patent Document 2] JP 2010-37916 A [Patent Document 3] JP 2010-95880 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, even now, there is a demand for further shortening the wetting-drying period.

[0008] Therefore, the present invention provides a method and system for treating a concrete structure, which can more efficiently remove alkaline components from a concrete structure after pouring and reduce the emission of ammonia. [Means for solving the problem]

[0009] The present invention has been made to solve at least some of the above-mentioned problems, and can be realized in the following aspects or application examples.

[0010] [1] One aspect of the method for treating a concrete structure according to the present invention is a method for treating a concrete structure after pouring, comprising the steps of: The method is characterized in that a wetting treatment is carried out in which the surface of the concrete structure is wetted with treated water having carbon dioxide gas dissolved therein.

[0011] [2] In one embodiment of the above-mentioned method for treating a concrete structure, In the wet treatment, the treatment water having a pH of 4.5 or more and 5.5 or less can be used.

[0012] [3] In one embodiment of the above-mentioned method for treating a concrete structure, The treated water can be produced by dissolving carbon dioxide gas in water by bubbling at the site where the concrete structure is poured.

[0013] [4] In one embodiment of the above-mentioned method for treating a concrete structure, The treated water can wet the surface of the concrete structure by immersion or spraying.

[0014] [5] In one embodiment of the above-mentioned method for treating a concrete structure, After the wetting process, a drying process is carried out to dry the surface of the concrete structure wetted with the treatment water; The wetting treatment and the drying treatment constitute one cycle of wetting-drying treatment, and the cycle is repeated for a predetermined period of time; The cycle can be performed on average 1 to 3 times per day.

[0015] [6] In one embodiment of the above-mentioned method for treating a concrete structure, The predetermined period of time may be 7 to 14 days.

[0016] [7] In one embodiment of the above-mentioned method for treating a concrete structure, The concrete structure is a box-like building having a floor, a wall, and a ceiling that form an internal space therein, The concrete structure constituting the floor is moistened by storing the treated water on the floor, After the wetting step in the wetting-drying treatment is completed, the treated water is collected from above the floor, thereby removing the alkaline components from the surface of the concrete structure.

[0017] [8] In one embodiment of the above-mentioned method for treating a concrete structure, The drying step in the wet-dry treatment can fix the alkaline components on the surface of the concrete structure as carbonates or hydrogen carbonates to the concrete structure.

[0018] [9] In one embodiment of the above-mentioned method for treating a concrete structure, After the predetermined period of wetting-drying treatment is completed, the interior space of the concrete structure can be further subjected to ventilation and dehumidification treatment.

[0019]

[10] One aspect of the concrete structure treatment system according to the present invention is a treatment system for a concrete structure after pouring, comprising: A mixing device for dissolving carbon dioxide gas in water to produce treated water; a wet treatment device for wetting the surface of the concrete structure; The present invention is characterized by comprising:

[0020]

[11] In one embodiment of the treatment system for a concrete structure, The wet treatment device may include a treatment tank in which the concrete structure is immersed in the treatment water.

[0021]

[12] In one embodiment of the treatment system for a concrete structure, The concrete structure is a box-like building having a floor, a wall, and a ceiling that form an internal space therein, The wet treatment device includes a sprinkler device that sprinkles the treated water onto the surface of the concrete structure, The processing system includes: A recovery device that recovers the treated water that accumulates on the concrete structure that constitutes the floor; A ventilation device for ventilating an internal space of the concrete structure; A dehumidifying device for dehumidifying an internal space of the concrete structure; The sensor may further include: Effect of the Invention

[0022] According to the concrete structure treatment method and concrete structure treatment system of the present invention, it is possible to more efficiently remove alkaline components from a concrete structure after pouring, and reduce the release of ammonia. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic configuration diagram of a concrete structure treatment system according to an embodiment of the present invention; [Diagram 2] 2 is a flowchart of a method for treating a concrete structure according to the present embodiment. [Diagram 3] 1 is a graph showing the mass change rate (%) versus age (days) of test specimens of Example and Comparative Examples 1 and 2. [Figure 4] 1 is a graph showing the ammonia emission rate (μg / m2·h) versus material age (days) of test specimens for Example and Comparative Examples 1 and 2. [Diagram 5] This is a graph in which a part of the graph in Figure 4 is excerpted and the vertical axis is represented linearly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are necessarily essential components of the present invention.

[0025] 1. Concrete structure treatment system A treatment system 10 for a concrete structure 1 according to this embodiment (hereinafter simply referred to as the "treatment system 10") will be described in detail with reference to Fig. 1. Fig. 1 is a schematic configuration diagram of the treatment system 10 according to this embodiment.

[0026] As shown in Fig. 1, the treatment system 10 according to this embodiment is a treatment system 10 for a concrete structure 1 after pouring, and includes a mixer 20 and a moistening treatment device 30. The treatment system 10 may further include, for example, a recovery device 40, a ventilation device 50, and a dehumidifier 60. The treatment system 10 can perform a treatment method for the concrete structure 1, which will be described later.

[0027] The concrete structure 1 may be a box-like structure having a floor, walls, and a ceiling that form an internal space 2. Alkaline components are generated on the floor surface 1a, the wall surface 1b, and the ceiling surface 1c that face the internal space 2 of the concrete structure 1. Assuming that the concrete structure 1 using the treatment system 10 is a structure from which it is desired to remove alkaline components. An example of a building having an internal space 2 as shown in Fig. 1 will be described below, but the present invention is not limited to this. For example, the building may be a precast concrete (PCa) structure (such as a foundation, floor plate, pillars, beams, etc.) that constitutes the building, or a PCa product that is to be installed in a building that does not tolerate alkaline components. In the case of PCa, the internal space 2 is the space above the floor surface 1a, which is a PCa manufacturing factory.

[0028] The mixer 20 produces treated water by dissolving carbon dioxide gas in water. A water supply device 21 and a carbon dioxide gas supply device 22 are connected to the mixer 20. The water supply device 21 may be, for example, a water supply facility installed at the pouring site of the concrete structure 1, or may be a tank for storing tap water. If it is a water supply facility, it can be easily used at the pouring site. The water supplied from the water supply device 21 to the mixer 20 may contain a small amount of liquid other than water, such as ethanol. The carbon dioxide gas supply device 22 is a container for storing carbon dioxide gas, such as a cylindrical high-pressure gas container. The mixer 20 is, for example, a bubbling tank. In the mixer 20, carbon dioxide gas is blown from the carbon dioxide gas supply device 22 into the water supplied from the water supply device 21 to the mixer 20, and the water is bubbled to produce treated water containing carbonated water (H2CO3) in which carbon dioxide gas is dissolved in water. The mixing device 20 is not limited to a bubbling tank, but may be a device that introduces carbon dioxide gas into water flowing through a pipe and mixes it, or may be a device that uses a dispersion means such as a static mixer, and any known device for producing carbonated water can be used.

[0029] The wetting treatment device 30 is a device that wets the surface of the concrete structure 1. The wetting treatment device 30 is connected to the mixer 20, and treated water produced in the mixer 20 is supplied to the wetting treatment device 30.

[0030] The wet treatment device 30 can include a treatment tank for immersing the concrete structure in the treatment water. The treatment tank can hold the treatment water and the concrete structure inside, and is preferably provided with a lid member that can seal the inside. The lid member can suppress the emission of carbon dioxide gas inside the treatment tank. The lid member may be a synthetic resin sheet with excellent gas barrier properties or a metal lid as long as it can suppress the emission of carbon dioxide gas, and there is no restriction on the material or shape. Since it is not practical to immerse the entire concrete structure 1 in FIG. 1, it can be used for a concrete structure of a size that can be immersed in the treatment tank. If the concrete structure can be immersed using the treatment tank, it can be assumed that the alkali components can be removed more efficiently and the release of ammonia can be reduced by immersing it for a short period of time as in the examples described below. This can shorten the time required for wet treatment.

[0031] Moreover, the wet treatment device 30 may be provided with a sprinkler device for sprinkling treated water onto the surface of the concrete structure 1 instead of the treatment tank. In the following explanation, the treatment system 10 capable of wetting the surface of the concrete structure 1 using a sprinkler device as the wet treatment device 30 will be explained, but a treatment tank may also be used. The wet treatment device 30, which is a sprinkler device, can wet the surface of, for example, the concrete structure 1, which is too large to fit into the treatment tank, by sprinkling treated water onto it. The sprinkler device is, for example, a high-pressure washer or a sprinkler that has the performance of evenly wetting the wall surface 1b and the ceiling surface 1c. It is preferable that the treated water is covered by the sprinkler device and accumulates to a depth of, for example, about 1 cm to 2 cm. By using treated water containing carbonated water, the ammonia emission rate (μm / cm 2·h) can be reduced. In addition, because it is treated water (liquid), time is provided for the alkaline components to be ionized and dissolved in the treated water, and time is provided for the treated water to penetrate into the pores on the surface of the concrete structure 1 and generate carbonates, etc. On the other hand, when carbon dioxide gas is directly used for curing, a large tank is required to seal the carbon dioxide gas in the concrete structure 1, which is difficult to realize, but treated water containing carbonated water can be simply sprayed, which provides excellent workability.

[0032] The recovery device 40 recovers the treated water that accumulates on the concrete structure 1 that constitutes the floor. The recovery device 40 sucks up water from the surface 1a of the floor and discharges it, for example, into a discharge tank outside the concrete structure 1. For example, a drainage pump or the like can be used as the recovery device 40. By recovering the treated water with the recovery device 40, the alkaline components that have dissolved in the treated water can be removed. The treated water can then be discharged after adjusting the pH. Furthermore, when the wet treatment device 30 is equipped with a treatment tank, the recovery device 40 may be configured to be connected to the treatment tank, and the treated water inside the treatment tank may be recovered by the recovery device 40.

[0033] After the water is sprayed by the wetting treatment device 30 and the treated water is collected by the collection device 40, the surface of the concrete structure 1 is left to dry naturally or by forced drying. By further repeating the wetting-drying process, the alkaline components can be removed more efficiently and the emission of ammonia can be reduced.

[0034] The ventilation device 50 ventilates the internal space 2 of the concrete structure 1. After being moved and installed in the internal space 2 of the concrete structure 1, the ventilation device 50 can ventilate the internal space 2. Although it depends on the size of the internal space 2, for example, an explosion-proof blower can be used as the ventilation device 50.

[0035] The dehumidifier 60 dehumidifies the internal space 2 of the concrete structure 1. After being moved and installed in the internal space 2 of the concrete structure 1, the dehumidifier 60 can dehumidify the internal space 2. As the dehumidifier 60, a known dehumidifying dryer for indoor use can be adopted.

[0036] The ventilation and dehumidification processes by the ventilation device 50 and the dehumidification device 60 significantly shorten the so-called conventional concrete drying period, and can shorten the period to, for example, about 1 / 10 to 1 / 15 of the conventional general drying period, although this period depends on the size of the concrete structure 1. The drying period varies depending on the purpose of reducing alkaline components, the use and size of the building, etc.

[0037] In this way, according to the treatment system 10 of this embodiment, the alkaline components generated on the surface of the concrete structure 1 can be efficiently removed by the treated water, so that the emission of ammonia can be reduced. Furthermore, by reducing the emission of ammonia, the concrete drying period can be significantly shortened, and the building can be put into use earlier. Furthermore, during this concrete drying period, there is no need for an air purifying device having an expensive filter for adsorbing specific substances such as alkaline components, and the alkaline components can be removed at low cost.

[0038] 2. Treatment method for concrete structures The method for treating a concrete structure according to the present embodiment is a method for treating a concrete structure after casting, and is characterized in that a wetting treatment is performed in which the surface of the concrete structure is wetted with treated water in which carbon dioxide gas is dissolved. In the wetting treatment, the surface of the concrete structure can be wetted with treated water by immersion or spraying. The wetting treatment can be performed using the wet treatment device 30 of the treatment system 10 described above. In order to efficiently remove the alkaline components, in the case of immersion, it is preferable to maintain the surface of the concrete structure wetted with treated water for a predetermined period of time, and in the case of spraying, it is preferable to repeatedly perform the wetting treatment and the drying treatment. In the case of maintaining the surface wetted with treated water, the predetermined period is preferably, for example, 7 days or more. This is because it can be inferred that the effect is obtained in 7 days from the experimental results described later. In addition, in the case of immersion using a treatment tank, the wet surface of the concrete structure may be covered with the above-mentioned lid member in order to maintain the surface wetted with treated water.

[0039] For the wet treatment, water with a pH of 4.5 to 5.5 can be used. If the pH of the water is 4.5 or higher, it can be produced using carbon dioxide gas, and if the pH of the water is 5.5 or lower, the alkaline component can be efficiently dissolved in the water by the wet treatment. In addition, it is preferable that the pH of the treated water is 4.5 or more, since it is believed that the treated water will hardly corrode the concrete structure 1.

[0040] Since the treated water contains carbonated water, the water used contains at least fine bubbles (hereinafter referred to as "fine bubbles") due to the spraying, and the effects disclosed in JP 2010-95880 A can be expected. That is, the alkaline components contained in the concrete structure 1 are effectively decomposed by free radicals generated by crushing the fine bubbles contained in the treated water. Also, the amount of water sprayed on the concrete structure 1 can be reduced compared to when the treated water does not contain fine bubbles.

[0041] An example of performing a wet-dry treatment will be described in detail as a treatment method for a concrete structure 1 according to this embodiment (hereinafter simply referred to as a "treatment method") with reference to Fig. 2. Fig. 2 is a flowchart of the treatment method according to this embodiment.

[0042] As shown in FIG. 2, the treatment method according to the present embodiment is a treatment method for a concrete structure 1 (see FIG. 1) after casting, and at least a wetting step (S20) and a drying step (S30) are one cycle of wetting-drying treatment, and this cycle can be repeated for a predetermined period of time. In addition, when the wetting treatment is maintained for a predetermined period of time to remove the alkaline component, the wetting-drying treatment does not need to be repeated. In that case, the following number of times determination step (S40) and number of days determination step (S50) are unnecessary. The example of the treatment method in FIG. 2 can further include a treated water production step (S10), a recovery step (S22), a number of times determination step (S40), a number of days determination step (S50), and a ventilation and dehumidification step (S60). Each step shown in FIG. 2 will be described in order for an example using the treatment system 10 in FIG. 1. Note that the description overlapping with the treatment system 10 will be omitted.

[0043] S10: Treated water production step produces treated water by dissolving carbon dioxide gas in water, for example, by bubbling, at the site where the concrete structure 1 is poured. In the treated water production step (S10), for example, water is supplied from the water supply device 21 of the treatment system 10 to the mixer 20, and carbon dioxide gas is supplied from the carbon dioxide gas supply device 22 to the water and mixed to produce treated water. This is not limiting, and S20 may be performed using treated water produced in a factory or the like, for example.

[0044] S20: In the wetting step, a wetting treatment is performed to wet the surface of the concrete structure 1 with treated water having carbon dioxide dissolved therein. The wetting step (S20) can be performed, for example, by immersing the concrete structure 1 in a treatment tank provided in a wetting treatment device 30 arranged in the internal space 2 of the concrete structure 1 or by spraying treated water from a sprinkler device. In the wetting step using a sprinkler device, the concrete structure 1 can be a box-like building with a floor, walls and a ceiling that form the internal space 2 inside, and the surfaces (e.g. 1a, 1b, 1c) of the concrete structure 1 are wetted by spraying water. Also, the concrete structure 1 that constitutes the floor is wetted by collecting treated water on the floor.

[0045] In the wetting step (S20), the surface of the concrete structure 1 is wetted with treated water having a pH of 4.5 or more and 5.5 or less. If the pH of the treated water is 4.5 or more, it can be produced using carbon dioxide gas, and if the pH of the treated water is 5.5 or less, the alkaline components can be efficiently dissolved in the treated water by the wetting step. In addition, if the pH of the treated water is 4.5 or more, it is preferable because it is thought that the concrete structure 1 is hardly damaged.

[0046] S22: The recovery step is carried out after the wetting step (S20) in the wetting-drying treatment is completed, and the treated water is recovered from the floor of the concrete structure 1, thereby removing the alkaline components from the surface of the concrete structure 1. This is because the alkaline components are ionized and dissolved in the treated water, or carbonates or the like are generated and dissolved in the treated water, and can be recovered together with the treated water. be.

[0047] S30: The drying step is a step of drying the surface of the concrete structure 1 after the wetting step (S20). As a method of drying, it is preferable to use natural drying or a heating device in winter or the like, and to perform the drying in an indoor environment, for example, at a temperature of 20°C to 40°C and a relative humidity of 40% to 50%. The dry state of the surface of the concrete structure 1 can be observed by visual inspection.

[0048] The drying step in the wetting-drying treatment fixes the alkaline components on the surface of the concrete structure 1 as carbonates or bicarbonates to the concrete structure 1. In particular, there are many pores on the surface of the concrete structure 1, and some alkaline components remain in the pores without flowing out with the treatment liquid, but some of these alkaline components become stable carbonates or bicarbonates upon drying and are fixed as such to the surface of the concrete structure 1. For example, ammonia is liberated in a high pH environment and volatilizes as ammonia gas, but after the drying step (S30), some of the ammonia gas that reacts with the carbonated water in the treatment water remains in the pores as ammonium carbonate and is fixed.

[0049] The treatment method repeats a cycle of wetting and drying the surface of the concrete structure 1 with treated water for a predetermined period of time. This makes it possible to remove a large amount of alkaline components, such as ammonia, calcium compounds, potassium compounds, and amines, from the surface of the concrete structure 1 after casting in a short period of time, and as a result, the drying period of the concrete structure 1 can be significantly shortened. The degree of shortening of the drying period of the concrete structure 1 varies depending on the size of the concrete structure 1 (room), but for example, it can be shortened to about 1 / 10 to 1 / 15 compared to the conventional drying period of concrete left alone, and can be shortened to about 1 / 3 to 1 / 4 compared to the method of spraying water only.

[0050] S40: The number of times determination step determines whether the number of times the wetting-drying treatment cycles scheduled for that day have been performed. If the result of S40 is "NO", S20 to S30 are performed again, and if the result of S40 is "YES", S50 is performed. The number of times of S40 is set anew the next day, and the processing for that day is performed. It is preferable that the cycle is performed, for example, once to three times on average per day. Depending on the size of the concrete structure 1, taking into consideration the time required for the wetting-drying treatment and the time available for work at the casting site, it is preferable that the cycle is performed once to three times on average. The number of times determination step may be configured such that the planned number of times for each day is preset in a control device (not shown) provided in the processing system 10, and the control device counts and determines the number of wetting-drying treatment cycles.

[0051] S50: The number of days determination step determines whether the predetermined number of days has been performed. If the result of S50 is "NO", S20 to S40 are performed again, and if the result of S50 is "YES", S60 is performed. The predetermined period can be preset together with the number of times of S40, and is, for example, 7 to 14 days. If the cycle is performed 1 to 3 times per day on average, it is preferably about 7 to 14 days, depending on the size of the concrete structure 1. In the number of days determination step (S50), the scheduled number of times is preset in a control device (not shown) provided in the treatment system 10, and the control device may calculate the predetermined period together with the number of times of wet-dry treatment scheduled for each day, and make the determination.

[0052] The predetermined period is preferably the period until the concrete compressive strength reaches about 80%. The concrete compressive strength can be measured in accordance with JIS A 1108.

[0053] In the ventilation and dehumidification step S60, after the wetting and drying process has been completed for a predetermined period, ventilation and dehumidification processes are further performed on the internal space 2 of the concrete structure 1. In the ventilation and dehumidification step (S60), the air in the internal space 2 is ventilated by the ventilation device 50, and the air in the internal space 2 after ventilation is dehumidified by the dehumidification device 60. In FIG. 1, both the ventilation device 50 and the dehumidification device 60 are located outside the internal space 2, but they can be moved and installed in the internal space 2 during the ventilation and dehumidification step (S60).

[0054] By carrying out the ventilation and dehumidification step (S60), it is possible to forcibly exhaust gasified alkaline components such as ammonia from the room. This ventilation and dehumidification step (S60) can be carried out using an explosion-proof (e.g., plastic) blower and a dehumidification dryer. This ventilation and dehumidification step (S60) is desirably carried out for, for example, 40 to 50 days, although this differs depending on the size of the concrete structure 1 (room).

[0055] According to the treatment method of this embodiment, as described above, the ageing period of the concrete structure 1 can be significantly shortened, and the building can be used earlier. During this ageing period, there is no need for an air purifier having an expensive filter for adsorbing specific substances such as alkaline components, and alkaline components can be removed at low cost.

[0056] Furthermore, according to the treatment method of this embodiment, by using treated water with carbon dioxide gas dissolved therein, it is possible to efficiently remove alkaline components from the concrete structure 1 in a short period of time. In other words, by using treated water with carbon dioxide gas dissolved therein, the number of wet-dry cycles can be reduced compared to a case where carbon dioxide gas is not dissolved therein, and therefore the seasoning period can be significantly shortened. This can be inferred from the reduction in the ammonia emission rate in the examples described below.

[0057] In this way, the treatment method according to this embodiment is useful for constructing a concrete structure 1 where it is required that there is no alkaline component or that the amount of alkaline component is small, such as special exhibition rooms in art galleries, museums, and archives, and clean rooms used in semiconductor manufacturing. EXAMPLES

[0058] (1) Preparation of test specimens and immersion treatment Approximately 30 L of mortar was mixed to prepare the test specimens. The shape of the test specimens was a rectangular parallelepiped measuring 150 x 150 x 70 mm, and three test specimens were used. The mortar was mixed with a water / powder ratio of 0.5 / 1 and a cement / sand ratio of 3.0 / 1. Since it is desirable for a certain amount of ammonia to be emitted from the test specimens during the experiment, ground granulated blast furnace slag was added in an amount equivalent to replacing 5% of the cement mixture.

[0059] The formwork was removed from the specimens by the time the specimens were aged for 3 days, and the specimens were placed in a room with a room temperature of 20°C and a humidity of 60%. The specimens for the embodiment (shown as "H2Ocb" in Tables 1 and 2 and Figures 3 and 4) were immersed in treated water containing carbonated water from the age of 7 to the age of 14 days. The specimens for Comparative Example 1 (shown as "H2O" in Tables 1 and 2 and Figures 3 and 4) were immersed in tap water from the age of 7 to the age of 14 days. The immersion treatment was performed by immersing each specimen in treated water or tap water in a plastic container, and closing the lid with vinyl tape. After the immersion treatment was completed, the water adhering to each specimen was wiped off with a rag, and the specimens were placed again in a room with a room temperature of 20°C and a humidity of 60%. The specimens for Comparative Example 2 (shown as "NA" in Tables 1 and 2 and Figures 3 and 4) were left without immersion from the age of 7 to the age of 14 days. The immersion treatment conditions for each specimen are shown in Table 1.

[0060] [Table 1]

[0061] (2)Measurement method Each specimen was weighed at a specified age. Figure 3 shows the mass change rate (%) calculated from the measured values ​​to the initial values ​​based on the weighing results up to 28 days.

[0062] The pH and ammonia concentration of the soaking water were measured using test paper and a simple measurement kit. The ammonia generated from the test specimens was measured on a specified schedule using the following method. The measurement results are shown in Table 2 and Figures 4 and 5. The compressive strength was measured according to JIS A 1108, but no difference was found between the Example and Comparative Examples 1 and 2.

[0063] (a) The test specimens were removed from the container at the specified age (assumed to be 28 days) and then left to dry in the constant temperature and low humidity chamber described above for a specified period of time (assumed to be about 1 to 3 days, until the weight loss was largely reduced).

[0064] (b) The test specimen was placed in a 20 L stainless steel chamber (ventilation rate approximately 1.20 times / h) from which 400 ml of air was discharged.

[0065] (c) After about 6 hours had passed since (b), the ammonium ion concentration (mg / L) inside the chamber was measured using a gas detector.

[0066] (d) Based on the ammonia concentration measurement results, the test specimen area, ventilation rate, etc., the ammonia emission rate μg / (m 2 ·h) was calculated.

[0067] (3) Mass change rate As shown in Figure 3, the mass change rate was similar for all specimens up to 7 days after immersion, but increased (exceeded 100%) for the specimens of Example and Comparative Example 1 (H2cb, H2O) immersed at 14 days after immersion. The increase in mass change rate was greater for Comparative Example 1 (H2O) than for Example (H2Ocb). On the other hand, when the surface of the specimen of Example (H2Ocb) was visually observed, white precipitates thought to be calcium carbonate were observed, suggesting that carbonate had been produced.

[0068] (4) pH and ammonium ion concentration Table 2 shows the measurement results of the pH and ammonium ion concentration (mg / L) of the soaking water. The pH of the soaking water reached a maximum of 6.9 in the example (H2Ocb) in which carbonated water was used, whereas in Comparative Example 1 (H2O) in which tap water was used, it increased to 13 by the time the material was 10 days old (3 days after soaking began). In the case of the example (H2Ocb) in which carbonated water was used, the pH rose due to a neutralization reaction between the carbonated water and calcium hydroxide, an alkaline component of the concrete, but the change was smaller than in Comparative Example 1 (H2O). The ammonium ion concentration of the soaking water reached a maximum of 13 by the time the material was 14 days old (3 days after soaking began). 7 days), both were 1 mg / L, and there was no significant difference between the Example and Comparative Example 1. Note that no measurements were taken in the range exceeding pH 13.

[0069] [Table 2]

[0070] (5) Ammonia emission rate FIG. 4 shows the ammonia emission rate (μg / m) versus material age (days) of the test specimens of the example and comparative examples 1 and 2. 2 4. FIG. 5 is a graph of the graph of FIG. 4, in which the vertical axis is expressed in a linear scale.

[0071] The ammonia emission rate was 400 μg / (m) at 5 days of age in Comparative Example 2 (NA). 2 ·h), and then decreased exponentially to 80 μg / (m 2 The ammonia emission rate of the test specimen in Comparative Example 1 (HO) was measured from the 14th day of the material life, and the ammonia emission rate was 100 μg / (m 2 At 14 days of age, there was little difference in the ammonia emission rate between Comparative Examples 1 and 2.

[0072] On the other hand, the test specimen of the embodiment (H2Ocb) was measured on the 14th day, and the ammonia emission rate was 40 μg / (m 2 The test specimen of the embodiment had an ammonia emission rate that was reduced to about half that of the test specimens of Comparative Examples 1 and 2.

[0073] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments, or configurations that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0074] 1...concrete structure, 1a...floor surface, 1b...wall surface, 1c...ceiling surface, 10...treatment system, 20...mixing device, 21...water supply device, 22...carbon dioxide supply device, 30...wet treatment device, 40...recovery device, 50...ventilation device, 60...dehumidification device

Claims

1. A method for treating a concrete structure after pouring, comprising: A method for treating a concrete structure, comprising carrying out a wetting treatment in which the surface of the concrete structure is wetted with treated water having carbon dioxide gas dissolved therein.

2. The method for treating a concrete structure according to claim 1, A method for treating a concrete structure, wherein the wet treatment uses treated water having a pH of 4.5 or more and 5.5 or less.

3. The method for treating a concrete structure according to claim 1 or 2, A method for treating a concrete structure, characterized in that the treated water is produced by dissolving carbon dioxide gas in water by bubbling at the site where the concrete structure is poured.

4. The method for treating a concrete structure according to claim 1 or 2, A method for treating a concrete structure, characterized in that the surface of the concrete structure is wetted with the treatment water by immersion or spraying.

5. The method for treating a concrete structure according to claim 1 or 2, After the wetting process, a drying process is carried out to dry the surface of the concrete structure wetted with the treatment water; The wetting treatment and the drying treatment constitute one cycle of wetting-drying treatment, and the cycle is repeated for a predetermined period of time; A method for treating a concrete structure, characterized in that the cycle is carried out on average 1 to 3 times per day.

6. The method for treating a concrete structure according to claim 5, A method for treating a concrete structure, wherein the predetermined period is 7 to 14 days.

7. The method for treating a concrete structure according to claim 5, The concrete structure is a box-like building having a floor, a wall, and a ceiling that form an internal space therein, The concrete structure constituting the floor is moistened by storing the treated water on the floor, A method for treating a concrete structure, comprising recovering the treated water from above the floor after the wetting step in the wetting-drying treatment is completed, thereby removing alkaline components from the surface of the concrete structure.

8. The method for treating a concrete structure according to claim 5, A method for treating a concrete structure, characterized in that alkaline components on the surface of the concrete structure are fixed to the concrete structure as carbonates or hydrogen carbonates by the drying step in the wet-dry treatment.

9. The method for treating a concrete structure according to claim 5, A method for treating a concrete structure, characterized in that after the wetting-drying treatment for the specified period is completed, a ventilation and dehumidification treatment is further performed on the internal space of the concrete structure.

10. A treatment system for a concrete structure after casting, comprising: A mixing device for dissolving carbon dioxide gas in water to produce treated water; a wet treatment device for wetting the surface of the concrete structure; A treatment system for a concrete structure comprising:

11. 11. The system for treating a concrete structure according to claim 10, 13. A concrete structure treatment system, comprising: a treatment tank for immersing the concrete structure in the treatment water;

12. 11. The system for treating a concrete structure according to claim 10, The concrete structure is a box-like building having a floor, a wall, and a ceiling that form an internal space therein, The wet treatment device includes a sprinkler device that sprinkles the treated water onto the surface of the concrete structure, The processing system includes: A recovery device that recovers the treated water that accumulates on the concrete structure that constitutes the floor; A ventilation device for ventilating an internal space of the concrete structure; A dehumidifying device for dehumidifying an internal space of the concrete structure; A system for treating a concrete structure, further comprising:

Images