Concrete pouring method

Abstract

Remove the rainwater protection film that has become integrated with the concrete. [Solution] A concrete pouring method characterized by comprising: a concrete pouring step of pouring concrete during or when rainfall is expected; a coating / spraying step of applying or spraying an aqueous solution containing alginate onto the surface of the concrete; a rainwater protective film formation step of forming a rainwater protective film on at least a part of the surface by the reaction of the aqueous solution with polyvalent metal ions in the concrete; and a protective film removal step, which occurs after the rainwater protective film formation step and after the rainwater protective film has solidified and become integrated with the concrete, and then removes the rainwater protective film.

Description

Technical Field

[0001] The present invention relates to a method for placing concrete.

Background Art

[0002] When placing concrete during rainfall or when rainfall is predicted, rainwater may flow into the concrete before it hardens. As a result, the water-cement ratio of the concrete may increase, or the mortar component may flow out. Consequently, the quality of the concrete, such as its strength and durability, may deteriorate, and the performance of the structure constructed with such concrete may be impaired. Therefore, as a countermeasure in such cases, for example, in Patent Document 1, a dedicated liquid mainly composed of sodium alginate is applied to the concrete surface to form an insoluble gel film (rainwater protection film), thereby preventing contact between rainwater and the concrete.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If the above rainwater protection film is formed within about half a day, it is in a gel state and can be easily removed with a blower or the like. However, as time passes, for example, after the next day, the rainwater protection film solidifies and integrates (adheres) with the concrete. In this case, it becomes difficult to remove it even by using a blower or a high-pressure washer.

[0005] The present invention has been made in view of the above problems, and its object is to remove the rainwater protection film integrated with the concrete from the concrete.

Means for Solving the Problems

[0006] The main invention for achieving the above objective is a concrete placement method characterized by comprising: a concrete placement step of pouring concrete; a coating / spraying step of applying or spraying an aqueous solution containing alginate onto the surface of the concrete; a rainwater protective film formation step of forming a rainwater protective film on at least a part of the surface by the reaction of the aqueous solution with polyvalent metal ions in the concrete; and a protective film removal step, which occurs after the rainwater protective film formation step and after the rainwater protective film has solidified and become integrated with the concrete, and after removing the rainwater protective film.

[0007] Other features of the present invention will be revealed in the specification and drawings described below. [Effects of the Invention]

[0008] According to the present invention, a rainwater protective film integrated with concrete can be removed from the concrete while maintaining its smoothness. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram of the rainwater protection film 20. [Figure 2] This is a photograph showing the rainwater protection film 20. [Figure 3] This figure shows the rainwater protection film 20 integrated with the concrete 10. [Figure 4] This is a flowchart of the concrete pouring method according to the first embodiment. [Figure 5] This is a flowchart of the protective film removal step (S05) in the first embodiment. [Figure 6] Figure 6A shows the polisher 30 used in the first embodiment. Figure 6B shows the process of attaching the sandpaper 32 to the rotating body 31 of the polisher 30. Figure 6C shows the state with the sandpaper 32 attached to the polisher 30 (rotating body 31). Figure 6D shows the state of removing the rainwater protective film 20A with the polisher 30. [Figure 7] It is a flowchart of the concrete placing method of the second embodiment. [Figure 8] It is a flowchart of the protective film removal step (S15) in the second embodiment. [Figure 9] Figs. 9A to 9C are schematic views showing the state when removing the rainwater protective film 20A in the second embodiment. [Figure 10] It is a diagram showing the relationship between the amount of sodium carbonate and the removability of the rainwater protective film. [Figure 11] It is a diagram showing the evaluation results of the solubility of the alginate film by sodium salts.

Embodiments for Carrying Out the Invention

[0010] From the descriptions in the following specification and drawings, at least the following matters will become clear.

[0011] (Aspect 1) In the case of rainfall or when rainfall is predicted, a concrete placing step of placing concrete, an application / spraying step of applying or spraying an aqueous solution containing alginate on the surface of the concrete, and a rainwater protective film forming step of forming a rainwater protective film on at least a part of the surface, which is formed by the reaction of the aqueous solution with the polyvalent metal ions of the concrete, and a protective film removal step of removing the rainwater protective film after the rainwater protective film forming step and after the rainwater protective film has solidified and integrated with the concrete. A concrete placing method characterized by having these steps.

[0012] According to the concrete placing method of Aspect 1, the rainwater protective film integrated with the concrete can be removed from the concrete.

[0013] (Aspect 2) The concrete placing method according to Aspect 1, which has a surface finishing step of performing surface finishing after the concrete placing step, and it is desirable to perform the application / spraying step after the surface finishing step.

[0014] According to the concrete placing method of Mode 2, the surface (finished surface) of the concrete can be smoothed, and the finished surface can be protected.

[0015] (Mode 3) The concrete placing method according to Mode 1 or 2, wherein it is desirable that the protective film removal step is performed after the day following the day when the rainwater protective film is formed. In the present invention, "after the day following" means after the day following the day when the target concrete is placed.

[0016] According to the concrete placing method of Mode 3, since the rainwater protective film solidifies and integrates with the concrete after the day following, the rainwater protective film integrated with the concrete can be removed from the concrete.

[0017] (Mode 4) The concrete placing method according to any one of Modes 1 to 3, wherein it is desirable that the protective film removal step includes a scraping step of scraping off the rainwater protective film with a polisher.

[0018] According to the concrete placing method of Mode 4, the solidified rainwater protective film can be easily and surely removed by a polisher. Also, the smoothness of the concrete surface can be maintained as compared with the case of scraping off with a brush or the like.

[0019] (Mode 5) The concrete placing method according to Mode 4, wherein it is desirable that the scraping step is performed when water is not supplied or when water cannot be used.

[0020] According to the concrete placing method of Mode 5, the rainwater protective film can be removed without using water by using a polisher. Therefore, it is particularly suitable when water is not supplied or when water cannot be used.

[0021] (Mode 6) A concrete pouring method according to embodiment 4 or 5, wherein it is preferable that sandpaper is attached to the polisher.

[0022] According to the concrete placement method of embodiment 6, the solidified rainwater protective film can be efficiently removed. Furthermore, the smoothness of the concrete surface can be better ensured.

[0023] (Aspect 7) A concrete pouring method according to any one of embodiments 1 to 3, wherein the protective film removal step preferably includes an immersion step of immersing the rainwater protective film in an aqueous solution of sodium carbonate or sodium bicarbonate, and a removal step of removing the rainwater protective film that has returned to a gel state by the immersion step.

[0024] According to the concrete placement method of Embodiment 7, the solidified rainwater protective film can be returned to a gel-like state, allowing for easy and reliable removal. Furthermore, the smoothness of the concrete surface can be maintained more reliably.

[0025] (Pattern 8) The concrete placement method described in Embodiment 7, wherein the aqueous solution is preferably an aqueous solution of sodium carbonate.

[0026] According to the concrete pouring method of embodiment 8, the solidified rainwater protective film can be returned to a gel-like state.

[0027] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc., shown in each drawing are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

[0028] ===First Embodiment=== <Overview of Rainwater Protection Film 20> Figure 1 is an explanatory diagram of the rainwater protection film 20. Figure 2 is a photograph showing the rainwater protection film 20.

[0029] The rainwater protective film 20 is a thin film formed on the surface 11 of the concrete 10, as shown in Figure 1. Hereinafter, the rainwater protective film 20 may be simply referred to as the "thin film." In this embodiment, the concrete 10 on which the rainwater protective film 20 is formed is used in structures constructed of reinforced concrete (RC), steel-reinforced concrete (SRC), etc. Structures are constructed by pouring ready-mixed concrete (hereinafter sometimes simply referred to as "concrete"), which is produced by mixing cement, fine aggregate, coarse aggregate, etc. with water, into a formwork, and then removing the formwork after it has hardened. Since the present invention is effective for compositions containing a large amount of calcium source, such as cement, in this invention, "concrete" is a concept that includes mortar without coarse aggregate and paste without fine aggregate and coarse aggregate, and furthermore, it is a concept that also includes polymer cement mortar in which a part is replaced with polymer, and cement-based or gypsum-based self-leveling materials, which can be selected as appropriate.

[0030] Incidentally, concrete pouring into formwork is sometimes carried out during rainfall. Furthermore, for concrete poured into formwork to harden, a prescribed curing period must be elapsed after pouring. Rainfall may be expected during this prescribed curing period. During or when rainfall is expected, rainwater may flow into the concrete before it hardens. This can increase the water-cement ratio of the concrete or cause mortar components to leach out. As a result, the quality of the concrete, such as its strength and durability, may deteriorate, potentially impairing the performance of the structure constructed with that concrete.

[0031] Therefore, when it rains or when rainfall is expected, it is necessary to suppress the inflow of rainwater into the concrete before it hardens and to suppress the deterioration of the concrete's quality. As a countermeasure in such cases, as shown in Figure 1, by forming a rainwater protective film 20 on the surface 11 of the concrete 10, the inflow of rainwater into the concrete 10 before it hardens and the deterioration of the concrete 10's quality can be suppressed.

[0032] Note that Figure 1 shows a gap between the surface 11 of the concrete 10 and the rainwater protection film 20 for illustrative purposes, but in reality, the rainwater protection film 20 is formed on the surface 11 of the concrete 10 (without any gap between it and the surface 11).

[0033] In this embodiment, the rainwater protective film 20 can be formed by applying or spraying an aqueous sodium alginate solution onto the surface 11 of the concrete 10. The aqueous sodium alginate solution contains calcium ions (Ca) in the concrete 10. 2+ It has the property of reacting with and gelling ). Therefore, when an aqueous sodium alginate solution is applied or sprayed onto concrete 10 after it has been placed, it reacts with calcium ions in the concrete 10, forming a gel-like thin film as shown in Figure 2.

[0034] Furthermore, "gel-like" refers to a state in which a gel is substantially formed. A gel is defined as a polymer or its swollen form that has a three-dimensional network structure insoluble in any solvent, and is an intermediate form of matter between liquid and solid.

[0035] The sodium alginate aqueous solution may be applied to the surface 11 of the concrete 10 using a brush or roller, or it may be sprayed (sprayed) onto the surface 11 of the concrete 10 using a sprayer or the like.

[0036] Furthermore, the rainwater protective film 20 is not limited to a form formed by the reaction of an aqueous sodium alginate solution with calcium ions in the concrete 10. The rainwater protective film 20 may be formed from an aqueous solution containing an alkali metal salt, such as an aqueous potassium alginate solution, or from an aqueous solution containing an ammonium alginate salt. In other words, the rainwater protective film 20 may be formed from an aqueous solution containing an alginate. In addition, the rainwater protective film 20 may be formed from an aqueous solution containing an alginate, for example, magnesium ions (Mg) in the concrete 10. 2+ It may be formed by a reaction with ), or by a reaction with polyvalent metal ions in the concrete 10.

[0037] In this embodiment, the rainwater protective film 20 formed of this gel-like thin film covers the surface 11 of the concrete 10, as shown in Figure 1, and blocks contact between the concrete 10 and rainwater, thereby suppressing the inflow of rainwater into the concrete 10 before it hardens.

[0038] Furthermore, the rainwater protection film 20 of this embodiment can be suitably applied to the upper part of concrete on horizontal surfaces of structures such as slabs. The rainwater protection film 20 of this embodiment can also be applied to slope concrete. As described above, the rainwater protection film 20 is gel-like, so it remains on the concrete surface even on slopes and is less likely to sag. Moreover, the rainwater protection film 20 of this embodiment can also be applied to concrete on vertical surfaces. However, when applying to vertical surfaces, the concentration of the sodium alginate aqueous solution should be, for example, 10% or more, and the sagging of the rainwater protection film 20 can be suppressed by applying or spraying it onto the concrete in multiple stages.

[0039] Furthermore, in this embodiment, the rainwater protection film 20 is formed of a gel-like thin film as described above. Such a gel-like thin film can be easily removed from the concrete 10 with a blower or the like within about half a day after its formation.

[0040] However, after some time has passed since its formation (for example, the next day or later), the rainwater protective film 20 solidifies and becomes integrated (adheres) with the concrete 10.

[0041] Figure 3 shows the state in which the rainwater protection film 20 is integrated with the concrete 10.

[0042] As shown in Figure 3, for example, the gel-like rainwater protective film 20 solidifies and integrates (adheres) with the concrete 10 on or after the day following its formation. In this embodiment, "on or after the day following" means the day following the day the concrete 10 was poured, and more specifically, it means after the morning of the following day or later has passed since the concrete was poured during the day. More specifically, it means after at least 16 hours have passed. Hereinafter, the solidified rainwater protective film 20 may be referred to as the rainwater protective film 20A. Once the rainwater protective film 20 solidifies and integrates with the concrete 10 in this way, it becomes difficult to remove it from the concrete 10.

[0043] In addition, although concrete may be joined after the rainwater protective film 20 is removed, the surface 11 of the concrete 10 in this embodiment is a finished surface, and jointing is not necessary on the surface 11. In such cases, it is required to remove the rainwater protective film 20 while maintaining the smoothness of the surface 11 of the concrete 10. Conventional removal methods include removing the thin film using a metal scraper or a hard wire brush, but these methods not only require the time and effort of skilled workers, but also risk scraping off the surface 11 of the concrete 10, making it difficult to maintain the smoothness of the surface 11.

[0044] Therefore, in this embodiment, the rainwater protective film 20 can be removed after it has solidified and become integrated with the concrete 10, while maintaining the smoothness of the surface 11 of the concrete 10.

[0045] <Concrete pouring method according to the first embodiment> Figure 4 is a flowchart of the concrete pouring method according to the first embodiment.

[0046] First, concrete 10 is poured during or when rainfall is expected (S01: concrete pouring step).

[0047] After the concrete pouring step (S01), the surface of the concrete 10 is finished (for example, by troweling) to make the surface 11 smooth (S02: surface finishing step).

[0048] Next, an aqueous solution containing alginate is applied or sprayed onto the surface 11 (finished surface) of the concrete 10 (S03: application / spraying step). As mentioned above, the alginate may be an alkali metal salt such as sodium alginate, or an ammonium salt. The aqueous solution containing alginate may be applied to the surface of the concrete using a brush or roller, or sprayed (sprayed) onto the surface 11 of the concrete 10 using a sprayer.

[0049] To achieve the desired effect as a rainfall countermeasure, the concentration of alginate in the above aqueous solution should preferably be 0.2-20%, and the application (or spraying) rate of the aqueous solution should be 200g / m². 2 It is desirable that the above is true. Also, when converted to the amount of alginate to be applied, the amount of alginate to be applied is 0.4 g / m². 2 (preferably 1 g / m²) 2 The above is desirable.

[0050] When an aqueous solution containing alginate is applied or sprayed onto the surface 11 of the concrete 10, the aqueous solution containing alginate reacts with the polyvalent metal ions in the concrete to form a rainwater protective film 20 (S04: rainwater protective film formation step). As mentioned above, the polyvalent metal ions are calcium ions, but other polyvalent metal ions such as magnesium ions may also be used. In this embodiment, the concrete 10 can be protected from rainwater inflow in a simple manner.

[0051] If the formed rainwater protective film 20 is in a gel-like state, it can be easily removed with a blower or the like. However, as mentioned above, once the rainwater protective film 20 has solidified and become integrated (adhered) with the concrete 10 (become the rainwater protective film 20A), it becomes difficult to remove. Furthermore, in this embodiment, if the surface 11 of the concrete 10 is a finished surface, it is necessary to remove the rainwater protective film 20A while maintaining the smoothness of the surface 11. If the rainwater protective film 20A is scraped off with a brush or the like, the surface 11 of the concrete 10 may also be scraped off, impairing its smoothness.

[0052] In this embodiment, after the rainwater protective film 20 has solidified and become integrated with the concrete 10, the solidified rainwater protective film 20 (rainwater protective film 20A) is removed while maintaining the smoothness of the surface 11 (S05: protective film removal step). In this first embodiment, the rainwater protective film 20A is removed using a polisher, as will be described later.

[0053] Figure 5 is a flowchart of the protective film removal step (S05) in the first embodiment. Figure 6A shows the polisher 30 used in the first embodiment. Figure 6B shows the process of attaching the sandpaper 32 to the rotating body 31 of the polisher 30, and Figure 6C shows the state in which the sandpaper 32 is attached to the polisher 30 (rotating body 31). Figure 6D shows the state in which the rainwater protective film 20A is removed by the polisher 30.

[0054] The polisher 30 shown in Figure 6A is, for example, a machine for cleaning floors, and as shown in Figure 6B, has a disc-shaped rotating body 31 (for example, a cleaning brush, polishing pad, stripping pad, etc.). By rotating this rotating body 31 with an electric motor (not shown), floor cleaning, wax stripping, polishing, etc. can be performed efficiently.

[0055] In this embodiment, as shown in Figures 6B and 6C, the sandpaper 32 is attached to the rotating body 31 of the polisher 30 (S051).

[0056] Sandpaper 32 is paper coated with sand, glassy particles, abrasive grains, or other polishing materials, and is used for polishing. Sandpaper 32 is also called abrasive paper or sandpaper.

[0057] Then, as shown in Figure 6D, a polisher 30 with sandpaper 32 attached is placed on the rainwater protective film 20A (S052), and the polisher 30 is operated to scrape off the rainwater protective film 20A (S053: scraping process). At this time, there is a risk that the surface 11 of the concrete 10 may also be slightly scraped off, but the smoothness is maintained compared to when scraping with a hard wire brush or the like.

[0058] This allows the rainwater protective film 20A, which is integrated with the concrete 10, to be easily and reliably removed.

[0059] It is possible to remove the rainwater protective film 20A even without attaching the sandpaper 32 to the rotating body 31 (using only the rotating body 31). However, by attaching the sandpaper 32, the rainwater protective film 20A can be removed more efficiently, and the smoothness of the surface 11 can be better ensured.

[0060] As explained above, by using the polisher 30, the rainwater protective film 20A, which is integrated with the concrete 10, can be easily and reliably removed while maintaining the smoothness of the surface 11 of the concrete 10.

[0061] Furthermore, since the removal method using the polisher 30 does not use water, it can be used even when water is not supplied or when water cannot be used (for example, when there is a space on the lower floor where water inflow is undesirable). Therefore, it is particularly suitable in such cases.

[0062] ===Second Embodiment=== In the second embodiment, the method for removing the rainwater protective film 20A (protective film removal step) differs from that of the first embodiment.

[0063] Figure 7 is a flowchart of the concrete pouring method according to the second embodiment. Steps S11 to S15 shown in Figure 7 correspond to steps S01 to S05 of the first embodiment (Figure 4), respectively. Steps S11 to S14 are the same as steps S01 to S04 of the first embodiment, so a detailed explanation is omitted.

[0064] Figure 8 is a flowchart of the protective film removal step (S15) in the second embodiment. Figures 9A to 9C are schematic diagrams showing the state when the rainwater protective film 20A is removed in the second embodiment.

[0065] In the second embodiment, as shown in Figure 9A, an aqueous sodium carbonate solution 40 is sprayed onto the rainwater protective film 20A (S151). The method of spraying the aqueous sodium carbonate solution 40 is not particularly limited. Furthermore, it is not limited to spraying, but can also be applied by coating, etc. Sodium carbonate (Na2CO3) is a white powder and is used, for example, as a raw material for synthetic detergents and as a food additive. Sodium carbonate is readily soluble in water, and its aqueous solution (aqueous sodium carbonate solution 40) is colorless, transparent, and alkaline.

[0066] Next, the rainwater protection film 20A is immersed in the sodium carbonate aqueous solution 40 (S152: immersion step). In this immersion step, as shown in Figure 9B, the solid rainwater protection film 20A reacts with the sodium carbonate aqueous solution 40 and returns to a gel state (rainwater protection film 20).

[0067] Next, the gel-like rainwater protection film 20 is removed using a blower or wiper (S153: removal step). Since the rainwater protection film 20 is gel-like, it can be easily removed. As a result, the rainwater protection film 20 can be easily and reliably removed, as shown in Figure 9C.

[0068] Figure 10 shows the relationship between the amount of sodium carbonate and the removeability of the rainwater protective film. The amount of sodium carbonate is determined by the concentration (%) of the sodium carbonate aqueous solution and the amount of solution applied (g / m²). 2 It is calculated by the following: As shown in the figure, sodium carbonate is 10 g / m 2It was confirmed that the rainwater protective film could be removed by applying the above solution.

[0069] In this embodiment, an aqueous solution of sodium carbonate is used, but this is not the only option. Figure 11 shows the results of evaluating the solubility of alginate coatings with sodium salts. (Test conditions) For each sodium salt shown in Figure 11, a 3.0% aqueous solution was prepared. 3.0 g of alginate gel film was added to the bottle containing the aqueous solution, and the bottle was shaken to agitate the contents and check the degree of dissolution (solubility) of the film. (Test results) As shown in Figure 11, the alginate coating dissolved immediately with sodium carbonate. With sodium bicarbonate, the dissolution of the alginate coating was confirmed the following day. However, the alginate coating did not dissolve with other sodium salts. Based on these evaluation results, an aqueous solution of sodium bicarbonate may be used. However, an aqueous solution of sodium carbonate is more preferable.

[0070] As explained above, in the second embodiment as well, the rainwater protective film 20A integrated with the concrete 10 can be removed easily and reliably.

[0071] Furthermore, in the second embodiment, by spraying an aqueous sodium carbonate solution 40 onto the rainwater protective film 20A, the rainwater protective film 20A is returned to a gel-like state (rainwater protective film 20) before being removed, so that the rainwater protective film 20 can be removed without affecting the surface 11 of the concrete 10. In other words, the smoothness of the surface 11 of the concrete 10 can be maintained more reliably.

[0072] Furthermore, in the second embodiment, the rainwater protective film 20A can be easily removed even if the surface 11 of the concrete 10 is not smooth (i.e., if no surface finishing has been performed).

[0073] ===Other=== The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof. [Explanation of Symbols]

[0074] 10 Concrete 11 Surface 20 Rainwater protection membrane 20A rainwater protection membrane (solid) 30 Polisher 31. Solids of revolution 32 Sandpaper 40. Sodium carbonate aqueous solution

Claims

1. In the event of rainfall or when rainfall is expected, the concrete pouring step is used for pouring concrete, A coating / spraying step in which an aqueous solution containing alginate is applied or sprayed onto the surface of the concrete, A rainwater protective film forming step, in which a rainwater protective film is formed on at least a portion of the surface by the reaction of the aqueous solution with polyvalent metal ions in the concrete, After the rainwater protective film formation step, and after the rainwater protective film has solidified and become integrated with the concrete, a protective film removal step is performed to remove the rainwater protective film. A concrete pouring method characterized by having the following features.

2. A concrete pouring method according to claim 1, The concrete pouring step is followed by a surface finishing step, After the surface finishing step, the coating and spraying step is performed. A concrete pouring method characterized by the following features.

3. A concrete pouring method according to claim 1 or 2, The protective film removal step is performed on or after the day following the formation of the rainwater protective film. A concrete pouring method characterized by the following features.

4. A concrete pouring method according to claim 1 or 2, The protective film removal step includes a scraping step of scraping off the rainwater protective film with a polisher. A concrete pouring method characterized by the following features.

5. A concrete pouring method according to claim 4, The aforementioned scraping process is performed when water is not supplied or cannot be used. A concrete pouring method characterized by the following features.

6. A concrete pouring method according to claim 4, The polisher is equipped with sandpaper. A concrete pouring method characterized by the following features.

7. A concrete pouring method according to claim 1 or 2, The protective film removal step is, The rainwater protective film is immersed in an aqueous solution of sodium carbonate or sodium bicarbonate in an immersion step, A removal step is performed to remove the rainwater protective film that has returned to a gel state by the immersion step, Having, A concrete pouring method characterized by the following features.

8. A concrete pouring method according to claim 7, The aforementioned aqueous solution is an aqueous solution of sodium carbonate. A concrete pouring method characterized by the following features.

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