Concrete construction methods

Abstract

To shorten a period required from the start of concrete placement to the completion of finishing work.SOLUTION: The concrete construction method includes blending an admixture AD of a first blending amount BA1 into the concrete to be placed in a first period PD1; and blending an admixture AD of a second blending amount BA2 larger than the first blending amount BA1 into the concrete to be placed in a second period PD2 after the first period PD1. The admixture AD has a function of expanding concrete and a function of accelerating hardening of concrete.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a concrete construction method. [Background technology]

[0002] Various techniques for constructing concrete are known (see, for example, Patent Document 1). Patent Document 1 describes a method for constructing a concrete floor using a ride-on trowel, in which the temperature distribution of the concrete floor surface under construction, placed at the edge of the work area, is measured using an infrared thermometer, and the finishing work is carried out while avoiding the ride-on trowel entering areas with high temperatures. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-197987 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the concrete floor construction method described in Patent Document 1, even when the concrete floor is finished using a ride-on trowel, surface peeling after construction can be suppressed. Furthermore, even if surface peeling does not occur, color unevenness caused by excessive scraping with a ride-on trowel can be suppressed. However, when constructing concrete floors, the degree of concrete hardening varies depending on when the concrete is poured, which affects when finishing work can be carried out. Therefore, in areas where concrete is poured later, the start date for finishing work is delayed compared to areas where concrete is poured earlier. As a result, the time required from the start of concrete pouring to the completion of finishing work becomes longer across the entire construction area, sometimes extending into the late hours of the night, making it difficult to pour concrete on consecutive days. The present invention aims to provide a concrete construction method that can shorten the time required from the start of concrete pouring to the completion of finishing work. [Means for solving the problem]

[0005] To achieve the above objective, embodiments of the present invention are provided. The area where the concrete floor will be constructed includes both the first and second construction sections. During the first period In the aforementioned Section 1, which is spaced away from the building opening The concrete to be poured is mixed with the first proportion of admixtures, and in the second period which is after the first period, In the second section, which is closer to the building opening than the first section: This concrete construction method involves adding a second amount of the admixture, which is greater than the first amount, to the concrete to be poured, wherein the admixture has the function of causing the concrete to expand and the function of promoting the hardening of the concrete.

[0006] Furthermore, in the concrete construction method described above, the admixture is composed of an expansive composition having the function of expanding the concrete and a hardening accelerator having the function of promoting the hardening of the concrete, and the admixture is composed of 1 part by mass or more and 2 parts by mass or less of the hardening accelerator added to 100 parts by mass of the expansive composition.

[0007] Furthermore, in the concrete construction method described above, the admixture is prepared by mixing the expansive composition and the hardening accelerator in a certain ratio before adding the admixture to the concrete.

[0008] Furthermore, in the above concrete construction method, the admixture is mixed with respect to the concrete in a ratio of 1% or more and 2% or less.

[0009] Furthermore, in the concrete construction method described above, the concrete constitutes a concrete floor, and the first and second mixing ratios are determined so that the concrete floor finishing work performed in the first period and the concrete floor finishing work performed in the second period can be carried out at approximately the same time.

[0010] Also, in the above concrete construction method, among the concrete floors, the concrete is placed in the work area close to the building opening after the work area separated from the building opening in the concrete floor.

Effect of the Invention

[0011] According to the present invention, the period required from the start of placing the concrete to the completion of the finishing work can be shortened.

Brief Description of the Drawings

[0012] [Figure 1] It is a plan view showing an example of a method for constructing a concrete floor according to this embodiment. [Figure 2] It is a diagram showing an example of a construction process of a concrete floor according to this embodiment. [Figure 3] It is a diagram showing an example of a construction process of a conventional concrete floor.

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments will be described with reference to the drawings.

[0014] [1. Construction Method of Concrete Floor] First, referring to FIG. 1, a method for constructing a concrete floor will be described. FIG. 1 is a plan view showing an example of a method for constructing a concrete floor according to this embodiment. Directions are shown in FIG. 1. For example, the upward direction in FIG. 1 is north, and the right direction in FIG. 1 is east.

[0015] In FIG. 1, the work area CA is the range where the concrete floor is constructed. The work area CA is composed of a first work area CA1, a second work area CA2, and a third work area CA3. The first work area CA1, the second work area CA2, and the third work area CA3 are arranged in this order from north to south. The work area CA is set in a rectangular shape, and each of the first work area CA1, the second work area CA2, and the third work area CA3 is also set in a rectangular shape. Direction CD indicates the direction of concrete placement. That is, concrete is placed from north to south. The area of ​​construction section CA is, for example, 1200m². 2 Furthermore, the area AR1 of the first section CA1, the area AR2 of the second section CA2, and the area AR3 of the third section CA3 are, for example, 400m². 2 That is the case. When constructing a concrete floor, the thickness of the concrete is approximately 0.12m to 0.25m. In this embodiment, the thickness of the concrete in section CA is, for example, 0.20m.

[0016] In Section 1, CA1, concrete will be poured during Period 1, PD1. Period 1, PD1, is, for example, from 8:00 AM to 11:00 AM. Concrete will be poured in Section 2, CA2, during Period 2, PD2. Period 2, PD2, is, for example, from 11:00 AM to 2:00 PM. Concrete will be poured in Section 3, CA3, during Period 3, PD3. Period 3, PD3, is, for example, from 2 PM to 5 PM.

[0017] In this embodiment, concrete is a composite material obtained by mixing fine aggregate such as land sand, mountain sand, crushed stone, and crushed sand with coarse aggregate such as gravel and crushed stone, along with cement paste (a paste made by adding water to cement) and an AE (Air Entraining) water-reducing agent, a high-performance AE water-reducing agent, etc., and then hardening the mixture.

[0018] The concrete to be poured into Section 1 CA1 will contain admixture AD in a first mix ratio of BA1. The first mix ratio BA1 is, for example, 20 kg / m³. 3 That is, concrete 1m 3 In addition, 20 kg of admixture AD is added. The admixture AD has the function of causing concrete to expand and the function of accelerating the hardening of concrete. Furthermore, the amount BA of admixture AD in relation to the concrete is within a predetermined range (as described later, 20 kg / m³). 3 In addition, 30 kg / m 3Within the following ratio), the greater the blending amount BA, the more the functions of expanding the concrete and promoting the hardening of the concrete are improved.

[0019] The concrete placed in the second construction area CA2 is blended with the admixture AD of the second blending amount BA2. The second blending amount BA2 is greater than the first blending amount BA1. The second blending amount BA2 is determined so that, for example, the timing when the floor finishing work of the concrete placed in the second period PD2 becomes possible is substantially the same as the timing when the floor finishing work of the concrete placed in the first period PD1 becomes possible. The second blending amount BA2 is, for example, 22.5 kg / m 3 That is, 22.5 kg of the admixture AD is blended per 1 m 3 of concrete.

[0020] The concrete placed in the third construction area CA3 is blended with the admixture AD of the third blending amount BA3. The third blending amount BA3 is greater than the second blending amount BA2. The third blending amount BA3 is determined so that, for example, the timing when the floor finishing work of the concrete placed in the third period PD3 becomes possible is substantially the same as the timing when the floor finishing work of the concrete placed in the second period PD2 becomes possible. The third blending amount BA3 is, for example, 25 kg / m 3 That is, 25 kg of the admixture AD is blended per 1 m 3 of concrete.

[0021] A building opening AP is formed at the southern end of the third construction area CA3. The concrete constructed near the building opening AP is easily affected by solar radiation and wind, and the risk of cracking is relatively high compared to other places. Therefore, by making the blending amount BA of this part the largest, the risk of cracking of the concrete constructed near the building opening AP can be reduced.

[0022] In this embodiment, the third concrete mix amount BA3 in the third section CA3 is greater than the first concrete mix amount BA1 in the first section CA1 and the second concrete mix amount BA2 in the second section CA2. Therefore, the risk of cracking in the concrete constructed near the building opening AP can be reduced.

[0023] In other words, concrete should be poured in the section of the concrete floor that is close to the building opening (in this embodiment, section 3, CA3) after the section that is further away from the building opening (in this embodiment, section 1, CA1 and section 2, CA2). In this case, the third mix ratio BA3 in section 3, CA3 is greater than the first mix ratio BA1 in section 1, CA1, and the second mix ratio BA2 in section 2, CA2. Therefore, the strength of the concrete poured near the building opening can be increased. Consequently, the risk of cracking in the concrete poured near the building opening can be reduced.

[0024] [2.Admixture materials] Next, we will explain the admixture AD. The admixture AD consists of an expansive composition AD1 that has the function of expanding concrete, and a hardening accelerator AD2 that has the function of accelerating the hardening of concrete. Furthermore, the admixture AD is prepared by adding, for example, 5 parts by mass or more and 15 parts by mass or less of a hardening accelerator AD2 to 100 parts by mass of the expansive composition AD1. In this embodiment, for example, the admixture AD is prepared by mixing 10 parts by mass of a hardening accelerator AD2 to 100 parts by mass of the expansive composition AD1 before the admixture AD is blended into the concrete. Mixing 10 parts by mass of curing accelerator AD2 with 100 parts by mass of the expanding composition AD1 corresponds to an example of "mixing the expanding composition AD1 and the curing accelerator AD2 in a certain ratio." For example, 20 kg of admixture AD contains approximately 18.2 kg (= 20 × 10 / 11) of the expansive composition AD1 and approximately 1.8 kg (= 20 × 1 / 11) of the curing accelerator AD2. 5 parts by mass corresponds to an example of "1st part by mass". 15 parts by mass corresponds to an example of "second part by mass".

[0025] In this embodiment, the admixture AD is prepared by mixing 10 parts by mass of the hardening accelerator AD2 with 100 parts by mass of the expansive composition AD1 before adding the admixture AD to the concrete. Therefore, since it is not necessary to check the ratio of the expansive composition AD1 to the hardening accelerator AD2 when adding the admixture AD to the concrete, the process of adding the admixture AD can be made more efficient. For example, when the expansive composition AD1 and the hardening accelerator AD2 are mixed separately into concrete, it is necessary to confirm the amounts of the expansive composition AD1 and the hardening accelerator AD2. In contrast, in this embodiment, before mixing the admixture AD into the concrete, 10 parts by mass of the hardening accelerator AD2 are mixed with 100 parts by mass of the expansive composition AD1. Therefore, since it is not necessary to confirm the ratio of the expansive composition AD1 and the hardening accelerator AD2 when mixing the admixture AD into the concrete, the process of mixing the admixture AD can be made more efficient compared to when the expansive composition AD1 and the hardening accelerator AD2 are mixed separately into the concrete.

[0026] As the expanding composition AD1, you can use one that contains free lime (f-CaO) as the active ingredient, one that contains calcium sulfoaluminate such as 3CaO·3Al2O3·CaSO4 (hauyne) as the active ingredient, or one that contains both free lime and calcium sulfoaluminate as active ingredients. In particular, it is preferable that the expansion effect is exhibited by volume increase due to the hydration of free lime. The free lime content in the expanding composition AD1 is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.

[0027] In addition to the above components, the expanding composition AD1 contains the following hydraulic compounds: calcium silicates such as CaO·2SiO2(C2S) and CaO·3SiO2(C3S), CaO·Al2O3(CA), and 12CaO·7Al2O3(C 12A7) It may also contain calcium aluminates such as 3CaO·Al2O3(C3A), calcium aluminoferrites such as 4CaO·Al2O3·Fe2O3(C4AF) and 6CaO·2Al2O3·Fe2O3(C6A2F). It may also contain gypsum such as dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum.

[0028] The powderiness of the expandable composition AD1 is 2000 to 7000 cm² in Blaine specific surface area. 2 A value of / g is preferred, and the range is 3000-6500 cm². 2 / g is more preferable, 4000~6000cm 2 / g is even more preferable.

[0029] As the expandable composition AD1, "Taiheiyo N-EX" (product name) manufactured by Taiheiyo Material Co., Ltd. is preferably used.

[0030] The curing accelerator AD2 contains at least aluminum sulfate as an active ingredient. The aluminum sulfate content in the curing accelerator AD2 is preferably 50% by mass or more, and more preferably 70% by mass or more. Both anhydrous aluminum sulfate and aluminum sulfate containing crystal water can be used. Other components may include sulfates, carbonates, nitrates, and nitrites of alkali metals or alkaline earth metals.

[0031] As the curing accelerator AD2, "Aluminum Sulfate 14-18 Water" (product name) manufactured by Kanto Chemical Co., Ltd. is preferably used. Alternatively, as the curing accelerator AD2, "Aluminum Sulfate for Wastewater" (product name) manufactured by Hokuriku Chemicals Co., Ltd. is preferably used.

[0032] As described above, the admixture AD is composed of 100 parts by mass of the expandable composition AD1 to an amount of curing accelerator AD2 of 5 parts by mass or more and 15 parts by mass or less. If the hardening accelerator AD2 is less than 5 parts by mass, the effect of accelerating the end of bleeding and the start of setting after concrete placement may be reduced. If the amount of hardening accelerator AD2 exceeds 15 parts by mass, it may adversely affect the fresh properties of the concrete, such as slump loss.

[0033] Furthermore, the admixture AD is added at a rate of 20 kg / m³ relative to the concrete. 3 In addition, 30 kg / m 3 The mixture is formulated in the following proportions. Specifically, the amount of BA used is 20 kg / m³. 3 In addition, 30 kg / m 3 The following applies: The blending amount BA is 20 kg / m 3 If the value is less than this, the effects of starting the floor finishing process earlier and shortening the setting time may be reduced. Furthermore, the blending amount BA is 30 kg / m³ 3 If the temperature exceeds a certain level, excessive expansion may cause cracks to appear in the hardened concrete. 20 kg / m 3 This corresponds to an example of the "first proportion". 30 kg / m 3 This corresponds to an example of the "second proportion."

[0034] [3. Conventional construction process] Next, with reference to Figures 2 and 3, we will compare the construction process of a conventional concrete floor with the construction process of a concrete floor according to this embodiment. Figures 2 and 3 illustrate the case of constructing a concrete floor in the work area CA shown in Figure 1. In Figures 2 and 3, the vertical axis represents time T. In this embodiment, we will describe the case where the ambient temperature is, for example, 10°C to 20°C.

[0035] First, let's explain the conventional construction process for concrete floors, referring to Figure 3. Figure 3 is a diagram showing an example of the conventional construction process for concrete floors. In conventional concrete floor construction, the concrete poured into section CA contains, for example, a first mix ratio BA1 of admixture AD. The first mix ratio BA1 is, for example, 20 kg / m³. 3 That is the case. The first step, PR1, is the construction process for the concrete floor in the first work section, CA1.

[0036] In the first process PR1, at time TS1, step S1, "concrete placement," begins. A concrete agitator truck and a concrete pump truck are used for concrete placement. The pump truck pumps the ready-mix concrete discharged from the concrete agitator truck to the construction site and places the concrete into the ground. Next, step S2, "rough leveling of the earthwork," is performed. In rough leveling of the earthwork, workers use hoes, shovels, etc., to level the piles of concrete that have been poured.

[0037] Next, Step S3, "Leveling the Floor," is performed. In leveling the floor, the concrete is leveled by workers using rakes and other tools, with pre-prepared level points as a guide. Next, step S4, "leveling," is performed. In leveling, a circular level is created using a leveling machine, a guide rod, etc. Additionally, a worker places a ruler on top of the circular level to create a strip-shaped level line.

[0038] Next, step S5, "ruler leveling," is performed. In ruler leveling, a worker stands in the center of two parallel level lines, creating an even larger level line surface. The worker also performs level checks using a leveling machine or similar device while leveling the surface. Next, step S6, "post-finishing of joints," is performed. In post-finishing of joints, once the surface of the concrete has begun to harden, finishing work is carried out around joints such as doors and window frames, as well as around columns and walls.

[0039] Next, step S7, "leveling," is performed. In leveling, once the concrete has hardened to the point where a worker can stand quietly on it and leave slight footprints (for example, footprints no longer deeper than 6 mm), leveling is performed using a trowel or wooden trowel. Time TF1 is the start time of leveling in step S7 of the first process PR1. Next, step S8, "trowel finishing," is performed. In trowel finishing, finishing work is carried out using a finishing trowel. Time TE1 is the time when trowel finishing is completed and the concrete floor construction process is finished.

[0040] In this embodiment, the case where step S8 is "trowel finish" is described, but it is not limited to this. Step S8 can be any "finish" specified in the design documents, etc. For example, the finishing method may be a brush finish, a mirror finish, etc.

[0041] The period P11 from time TS1 to time TE1 is the work period of the first process PR1. Time TS1 is, for example, 8:00 AM. Time TF1 is, for example, 3:00 PM. Time TE1 is, for example, 5:00 PM. That is, the period P11 is, for example, 9 hours.

[0042] The second process, PR2, is the construction process for the concrete floor in the second work section, CA2. The second process, PR2, consists of steps S1 to S8, similar to the first process, PR1. Time TS2 is the start time of "concrete pouring" in step S1 of the second process, PR2. Time TF2 is the start time of "leveling" in step S7 of the second process, PR2. Time TE2 is the time when the construction process for the concrete floor in the second process, PR2, is completed.

[0043] The period P12 from time TS2 to time TE2 is the work period for the second process PR2. Time TS2 is, for example, 11:00 AM. Time TF2 is, for example, 6:00 PM. Time TE2 is, for example, 8:00 PM. That is, the period P12 is, for example, 9 hours.

[0044] As described above, in the construction of conventional concrete floors, the concrete placed in section CA contains, for example, admixture AD in a first mix ratio of BA1. That is, the mix ratio BA of admixture AD in the concrete placed in section CA2 is the same as the mix ratio BA of admixture AD in the concrete placed in section CA1. Therefore, the hardening rate of the concrete placed in section CA2 is approximately the same as the hardening rate of the concrete placed in section CA1. Also, the area AR1 of section CA1 is the same as the area AR2 of section CA2. Therefore, the period from the start time of concrete placement (time TS2) to the start time of surface correction (time TF2) in section CA2 is approximately the same as the period from the start time of concrete placement (time TS1) to the start time of surface correction (time TF1) in section CA1. As a result, period P12 is approximately the same as period P11.

[0045] The third process, PR3, is the construction process for the concrete floor in the third work section, CA3. The third process, PR3, consists of steps S1 to S8, similar to the first process, PR1, and the second process, PR2. Time TS3 is the start time of "concrete pouring" in step S1 of the third process, PR3. Time TF3 is the start time of "leveling" in step S7 of the third process, PR3. Time TE3 is the time when the construction process for the concrete floor in the third process, PR3, is completed.

[0046] The period P13 from time TS3 to time TE3 is the work period for the third process PR3. Time TS3 is, for example, 2 PM. Time TF3 is, for example, 9 PM. Time TE3 is, for example, 11 PM. That is, the period P13 is, for example, 9 hours. Furthermore, since the start time (time TS1) for Section 1 CA1 is 8:00 AM and the end time (time TE3) for Section 3 CA3 is 11:00 PM, the total working time PTA for Section CA is 15 hours.

[0047] In conventional concrete floor construction, the proportion BA of admixture AD in the concrete poured in Section 3 CA3 is the same as the proportion BA of admixture AD in the concrete poured in Section 1 CA1. Therefore, period P13 is approximately the same as period P11.

[0048] As mentioned above, in the conventional concrete floor construction process, the start time (time TS1) for work section CA is 8:00 AM, and the end time (time TE3) for work section CA is 11:00 PM. Thus, the conventional concrete floor construction process sometimes required a long amount of time. As a result, it was sometimes not possible to carry out concrete floor construction on consecutive days. In addition, because the end time (time TE3) was 11:00 PM, it was sometimes difficult to carry out work in environments with restrictions on working hours, such as urban areas.

[0049] [4. Construction process of this embodiment] Next, the construction process of the concrete floor according to this embodiment will be described with reference to Figure 2. Figure 2 is a diagram showing an example of the construction process of the concrete floor according to this embodiment. In this embodiment, as described with reference to Figure 1, the concrete to be poured into the first work section CA1 is mixed with, for example, a first mix ratio BA1 of admixture AD. The first mix ratio BA1 is, for example, 20 kg / m³. 3 Furthermore, the concrete to be poured into the second section CA2 will contain, for example, a second mix ratio of admixture AD BA2. The second mix ratio BA2 is, for example, 22.5 kg / m³. 3 Furthermore, the concrete to be poured in the third section CA3 will contain, for example, admixture AD in a third mixing ratio of BA3. The third mixing ratio BA3 is, for example, 25 kg / m³. 3 That is the case.

[0050] Since the second mix ratio BA2 of the concrete placed in Section 2 CA2 is greater than the first mix ratio BA1 of the concrete placed in Section 1 CA1, the hardening rate of the concrete placed in Section 2 CA2 is faster than the hardening rate of the concrete placed in Section 1 CA1. Similarly, since the third mix ratio BA3 of the concrete placed in the third section CA3 is greater than the second mix ratio BA2 of the concrete placed in the second section CA2, the hardening rate of the concrete placed in the third section CA3 is faster than that of the concrete placed in the second section CA2.

[0051] The first step, PR1, is the construction process for the concrete floor in the first work section, CA1. The first step, PR1 shown in Figure 2, is identical to the first step, PR1 shown in Figure 3. In other words, the first process PR1 consists of steps S1 to S8. Time TS1 is the start time of "concrete pouring" in step S1 of the first process PR1. Time TF1 is the start time of "leveling" in step S7 of the first process PR1. Time TE1 is the time when the concrete floor construction process in the first process PR1 is completed.

[0052] The period P21 from time TS1 to time TE1 is the work period of the first process PR1. Time TS1 is, for example, 8:00 AM. Time TF1 is, for example, 3:00 PM. Time TE1 is, for example, 5:00 PM. That is, the period P21 is, for example, 9 hours.

[0053] The second stage, PR2, is the construction process for the concrete floor in the second section, CA2. The second process PR2 consists of steps S1 to S8, similar to the first process PR1. Time TS2 is the start time of "concrete pouring" in step S1 of the second process PR2. Time TF2 is the start time of "leveling" in step S7 of the second process PR2. Time TE2 is the time when the concrete floor construction process in the first process PR1 is completed.

[0054] The period P22 from time TS2 to time TE2 is the working period of the second process PR2. Time TS2 is, for example, 11:00 AM. Time TF2 is, for example, 4:00 PM. Time TE2 is, for example, 6:00 PM. That is, the period P22 is, for example, 7 hours.

[0055] As described above, the hardening rate of the concrete placed in Section 2 CA2 is faster than that of the concrete placed in Section 1 CA1. Also, the area AR1 of Section 1 CA1 is the same as the area AR2 of Section 2 CA2. Therefore, the period from the start time of "concrete placement" (time TS2) to the start time of "leveling" (time TF2) in Section 2 CA2 is, for example, 2 hours shorter than the period from the start time of "concrete placement" (time TS1) to the start time of "leveling" (time TF1) in Section 1 CA1. As a result, period P12 is, for example, 2 hours shorter than period P11.

[0056] The third stage, PR3, is the construction process for the concrete floor in the third section, CA3. The third process PR3 consists of steps S1 to S8, similar to the first process PR1 and the second process PR2. Time TS3 is the start time of "concrete pouring" in step S1 of the third process PR3. Time TF3 is the start time of "leveling" in step S7 of the third process PR3. Time TE3 is the time when the concrete floor construction process in the third process PR3 is completed.

[0057] The period P23 from time TS3 to time TE3 is the working period of the third process PR3. Time TS3 is, for example, 2 PM. Time TF3 is, for example, 5 PM. Time TE2 is, for example, 7 PM. That is, the period P12 is, for example, 5 hours. Furthermore, since the start time (time TS1) for the first work section CA1 is 8:00 AM and the end time (time TE3) for the third work section CA3 is 7:00 PM, the total working time PTB for each work section CA is 11 hours. In other words, the total working time PTB for each work section CA in this embodiment is 4 hours shorter than the total working time PTA for each work section CA in the conventional model.

[0058] As described above, the hardening rate of the concrete placed in Section 3 CA3 is faster than that of the concrete placed in Section 2 CA2. Also, the area AR2 of Section 2 CA2 is the same as the area AR3 of Section 3 CA3. Therefore, the period from the start time of "concrete placement" (time TS3) to the start time of "leveling" (time TF3) in Section 3 CA3 is, for example, 2 hours shorter than the period from the start time of "concrete placement" (time TS2) to the start time of "leveling" (time TF2) in Section 2 CA2. As a result, period P13 is, for example, 2 hours shorter than period P12.

[0059] As described above, in the concrete floor construction process of this embodiment, the start time (time TS1) for work area CA is 8:00 AM, and the end time (time TE3) for work area CA is 7:00 PM. Thus, in the concrete floor construction process of this embodiment, the total work time PT is reduced by 4 hours compared to the conventional concrete floor construction process shown in Figure 2. Therefore, it becomes possible to carry out concrete floor construction in multiple work areas on consecutive days. In addition, since the end time (time TE3) is 7:00 PM, it becomes possible to carry out work in environments where working hours are restricted, such as in urban areas.

[0060] [5. Effects of this embodiment] As described above, in the concrete construction method according to this embodiment, the concrete to be poured in the first period PD1 is mixed with admixture AD in a first mixing ratio BA1, and the concrete to be poured in the second period PD2, which is later than the first period PD1, is mixed with admixture AD in a second mixing ratio BA2 that is greater than the first mixing ratio BA1, and the admixture AD has the function of causing the concrete to expand and the function of promoting the hardening of the concrete.

[0061] In other words, the admixture AD has the function of causing the concrete to expand and the function of promoting the hardening of the concrete. In the concrete to be poured during the first period PD1, the admixture AD is added in a first mixing ratio of BA1, and in the concrete to be poured during the second period PD2, which is later than the first period PD1, the admixture AD is added in a second mixing ratio of BA2, which is greater than the first mixing ratio of BA1. Therefore, the concrete poured in the second period (PD2) hardens faster than the concrete poured in the first period (PD1). Consequently, the timing at which finishing work can be done on the concrete poured in the second period (PD2) can be accelerated. Therefore, the time required from the start of concrete pouring to the completion of finishing work can be shortened.

[0062] Furthermore, the admixture AD is composed of an expansive composition AD1 that has the function of expanding concrete and a hardening accelerator AD2 that has the function of accelerating the hardening of concrete. The admixture AD is composed of 1 part by mass (for example, 5 parts by mass) or more and 2 parts by mass (for example, 15 parts by mass) or less of the hardening accelerator AD2 added to 100 parts by mass of the expansive composition AD1.

[0063] In other words, the admixture AD is composed of 1 part by mass (for example, 5 parts by mass) or more and 2 parts by mass (for example, 15 parts by mass) or less of a curing accelerator AD2 added to 100 parts by mass of the expansive composition AD1. Therefore, by pre-adding a hardening accelerator AD2 in an amount of 1 part by mass or more and 2 parts by mass or less to 100 parts by mass of the expansive composition AD1 to create the admixture AD, the process of mixing the admixture AD into concrete can be made more efficient. Furthermore, by setting the first and second mass portions to appropriate values, the balance between the function of expanding the concrete and the function of promoting the hardening of the concrete can be appropriately adjusted.

[0064] Furthermore, the admixture AD is composed of an expansive composition AD1 and a hardening accelerator AD2 mixed in a certain ratio before being incorporated into the concrete. Therefore, when mixing the admixture AD into concrete, there is no need to adjust the ratio of the expansive composition AD1 and the hardening accelerator AD2. Consequently, the process of mixing the admixture AD can be made more efficient compared to, for example, mixing the expansive composition AD1 and the hardening accelerator AD2 into concrete separately.

[0065] Furthermore, the admixture AD is added to the concrete in a 1% proportion (for example, 20 kg / m³). 3 ) or more, and the second proportion (for example, 30 kg / m³) 3 The following proportions are used for the blending:

[0066] In other words, the proportion of admixtures added to the concrete is the first proportion (for example, 20 kg / m³). 3 ) or more, and the second proportion (for example, 30 kg / m³) 3 ) The following applies: Therefore, by setting the proportion of admixtures added to the concrete to 1% or higher, it is possible to suppress the reduction in the effect of starting the floor finishing process earlier and shortening the setting time. Furthermore, by setting the proportion of admixtures added to the concrete to 2% or lower, it is possible to reduce the possibility of cracks occurring in the hardened concrete due to excessive expansion.

[0067] Furthermore, the concrete is used to form a concrete floor, and the first mix ratio BA1 and the second mix ratio BA2 are determined so that the concrete floor finishing work performed in the first period PD1 and the concrete floor finishing work performed in the second period PD2 can be carried out at approximately the same time.

[0068] In other words, the first mix ratio BA1 and the second mix ratio BA2 are determined so that the concrete floor finishing work to be performed in the first period PD1 and the concrete floor finishing work to be performed in the second period PD2 can be carried out at approximately the same time. Therefore, the concrete floor finishing work performed in the first period PD1 and the concrete floor finishing work performed in the second period PD2 can be carried out at approximately the same time. Consequently, the work efficiency of the floor finishing work can be improved, as can the quality of the floor finishing. The quality of the floor finishing includes, for example, the degree of surface peeling after construction and the degree of color unevenness.

[0069] Furthermore, of the concrete floor, concrete is poured in the section adjacent to the building opening AP (e.g., section 3 CA3) after the section located further away from the building opening AP (e.g., section 1 CA1).

[0070] In other words, concrete is poured in sections close to the building opening AP (e.g., Section 3 CA3) after concrete is poured in sections further away from the building opening AP (e.g., Section 1 CA1). The third mix ratio BA3 in Section 3 CA3 is greater than the first mix ratio BA1 in Section 1 CA1 and the second mix ratio BA2 in Section 2 CA2. Therefore, the risk of cracking due to sunlight and wind can be reduced in concrete poured near the building opening AP.

[0071] [6. Other Embodiments] The present invention is not limited to the configuration of the above embodiments, and can be implemented in various forms without departing from its spirit. For example, this embodiment describes the construction of a concrete floor, but it is not limited to this. For example, a flat concrete structure can be constructed.

[0072] In this embodiment, we have described a case where work area CA consists of a first work area CA1, a second work area CA2, and a third work area CA3, but it is not limited to this. Work area CA may consist of, for example, two work areas, or work area CA may consist of, for example, four or more work areas. If a work area CA consists of, for example, four or more work areas, by appropriately adjusting the mixing ratio BA used in the concrete poured in each of the four or more work areas, the concrete floor finishing work in those four or more work areas can be performed at a more synchronized timing than in this embodiment. Therefore, the work efficiency of the floor finishing work can be improved, and the quality of the floor finishing can be improved. In other words, the more work areas that make up work area CA, the more precisely the mixing ratio BA can be adjusted, allowing the concrete floor finishing work in each work area to be performed at a more synchronized timing. As a result, the work efficiency of the floor finishing work can be further improved, and the quality of the floor finishing can be further improved.

[0073] This embodiment describes a case where the construction process for the concrete floor of work area CA is completed in one day, but is not limited to this. The construction process for the concrete floor of work area CA may also extend over two or more consecutive days.

[0074] In this embodiment, the first blending amount BA1 is 20 kg / m³ 3 Therefore, the second blending amount BA2 is 22.5 kg / m². 3 Therefore, the third blending amount BA3 is 25 kg / m². 3 The above describes the case, but it is not limited to this. Each of the first blending amount BA1, the second blending amount BA2, and the third blending amount BA3 is 20 kg / m³. 3 The above, and 30 kg / m 3 The following conditions must be met: the second formulation amount BA2 must be greater than the first formulation amount BA1, and the third formulation amount BA3 must be greater than the second formulation amount BA2.

[0075] In this embodiment, for convenience, the case in which the hardening rate of concrete is determined according to the mix ratio BA has been described, but the embodiment is not limited to this. The hardening rate of concrete is affected by ambient temperature, concrete thickness, floor area, pouring speed, etc. Therefore, it is preferable to determine the first mix ratio BA1 and the second mix ratio BA2 such that the period from the start time of concrete placement (time TS2) to the start time of leveling (time TF2) in the second construction section CA2 is the same as the period from the start time of concrete placement (time TS1) to the start time of leveling (time TF1) in the first construction section CA1, taking into consideration the outside temperature, concrete thickness, floor area, placement speed, etc. Furthermore, taking into consideration the outside temperature, concrete thickness, floor area, pouring speed, etc., it is preferable to determine the second mix ratio BA2 and the third mix ratio BA3 so that the period from the start time of concrete pouring (time TS3) to the start time of leveling (time TF3) in the third construction section CA3 is the same as the period from the start time of concrete pouring (time TS2) to the start time of leveling (time TF2) in the second construction section CA2. For example, it is preferable to increase the first formulation amount BA1, the second formulation amount BA2, and the third formulation amount BA3 as the outside temperature decreases. [Explanation of symbols]

[0076] AD admixture material AD1 Expanding Composition AD2 curing accelerator AP Building Openings AR1, AR2, AR3 area BA content BA1 1st compounding amount BA2 2nd compounding amount BA3 3rd compounding amount CA construction area CA1 1st section CA2 2nd section CA3 3rd section CD Direction P11, P12, P13, P21, P22, P23 period PD1 Period 1 PD2 Second Period PD3 Third Period PR1 1st process PR2 2nd process PR3 3rd process Total working time for PT, PTA, and PTB

Claims

1. The area in which the concrete floor is to be constructed includes the first work section and the second work section, In the first period, the concrete to be poured in the first work section, which is spaced apart from the building opening, is mixed with a first proportion of admixture. In the second period, which is later than the first period, the concrete to be poured in the second work section, which is on the building opening side of the first work section, is to be mixed with a second amount of the admixture that is greater than the first amount. The admixture has the function of causing the concrete to expand and the function of promoting the hardening of the concrete. Concrete construction methods.

2. The admixture comprises an expansive composition having the function of expanding the concrete and a hardening accelerator having the function of promoting the hardening of the concrete. The aforementioned admixture is prepared by adding 1 part by mass or more and 2 parts by mass or less of the curing accelerator to 100 parts by mass of the expandable composition. The concrete construction method according to claim 1.

3. The admixture is formed by mixing the expansive composition and the hardening accelerator in a certain ratio before incorporating the admixture into the concrete. The concrete construction method according to claim 2.

4. The concrete to be poured during the first period will be mixed with the first proportion of admixtures. In the concrete to be poured during the second period, which is later than the first period, the admixture is added in a second amount greater than the first amount. The aforementioned concrete constitutes a concrete floor. The admixture comprises an expansive composition having the function of expanding the concrete and a hardening accelerator having the function of promoting the hardening of the concrete. The admixture is formed by mixing the expansive composition and the hardening accelerator in a certain ratio before incorporating the admixture into the concrete. Concrete construction methods.

5. The admixture is mixed with respect to the concrete in a ratio of 1% or more and 2% or less. The concrete construction method according to any one of claims 1 to 4.

6. The first mix ratio and the second mix ratio are determined so that the concrete floor finishing work to be poured in the first period and the concrete floor finishing work to be poured in the second period can be performed at approximately the same time. The concrete construction method according to any one of claims 1 to 5.

7. Of the aforementioned concrete floor, the concrete is poured in the section adjacent to the building opening after the section that is spaced away from the building opening. The concrete construction method according to claim 6.

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