Concrete floor construction methods

Abstract

In the construction of concrete floor slabs using a rotary trowel, this invention provides a construction method that enables the construction of concrete floor slabs with a more flat surface by utilizing the concrete paste generated by using the rotary trowel. [Solution] A concrete floor construction method comprising a concrete pouring step, a leveling step in which the surface of the poured concrete is leveled using a rotary trowel, and a leveling step in which a leveling plate (21) is pressed against the surface of the concrete after the leveling step to level out any unevenness, wherein in the leveling step, concrete paste is generated on the surface of the concrete by operating the rotary trowel, and in the leveling step, the concrete paste is spread on the surface of the concrete with the leveling plate (21).

Description

Technical Field

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

Background Art

[0002] Conventionally, for a concrete floor as a building foundation, after placing the concrete, it was confirmed that the concrete had reached the desired thickness, and workers used a trowel to level the surface of the concrete for troweling finish.

[0003] Recently, in large-scale commercial facilities and factories, designs for large-area concrete floors have become mainstream. It is impossible to manually trowel finish such a large construction surface. Therefore, a rotary trowel with a blade serving as a trowel attached to a rotary arm that is rotationally driven substantially horizontally by an engine or a motor is used (see, for example, Patent Document 1 (FIG. 1)), and troweling finish is performed.

[0004] In a rotary trowel, three or four rotary arms are provided radially around a rotary shaft that is vertically extended by being interlocked and connected to the output shaft of an engine or a motor, and blades formed of a metal plate or the like are attached to each rotary arm to form a rotary trowel part. Further, in the rotary trowel, a rod-shaped operation handle is extended obliquely upward from the rotary trowel part, and the operator operates this operation handle to move the rotary trowel on the concrete during curing.

[0005] Specifically, when the rotary trowel part rotates the rotary shaft clockwise (right-handed rotation), when the operator presses down the operation handle to tilt the rotary shaft toward the front side on the operator's side (hereinafter referred to as "forward tilt"), the rotary trowel part moves to the right. Conversely, when the operator pulls up the operation handle to tilt the rotary shaft toward the back side (hereinafter referred to as "backward tilt"), the rotary trowel part moves to the left. The operator performs a pressing or pulling operation of the operation handle to make the rotary shaft forward tilt or backward tilt, and performs troweling finish while swinging the rotary trowel part left and right.

[0006] In particular, when the operator pushes down the operating handle to move the rotary trowel to the right, the operator does not move to the right themselves, but moves the rotary trowel as far to the right as possible, then the operator takes a few steps back, and then pushes up the operating handle to move the rotary trowel to the left. The operator does not move to the left themselves, but moves the rotary trowel as far to the left as possible, then the operator takes a few steps back, and then pushes down the operating handle to move the rotary trowel to the right. In other words, the operator moves the rotary trowel from side to side while moving directly backward. Note that if the rotation axis of the rotary trowel rotates counterclockwise, the operation of the operating handle is reversed.

[0007] In this case, because the rotating trowel section moves with the axis of rotation tilted forward or backward, the blade attached to the rotating trowel section is not necessarily on a horizontal plane. Therefore, the surface of concrete finished with a rotary trowel is not strictly horizontal, but has an inclination corresponding to the forward or backward tilt of the axis of rotation, resulting in a wavy surface with alternating upward and downward slopes in the direction the worker is moving backward.

[0008] Thus, even if the surface of the concrete was wavy, it was considered "no problem" as long as the desired tolerance conditions were met across the entire large area of ​​the concrete floor, and such wavy surfaces were generally not considered a problem. However, at least for concrete floors in factories where precision machining is performed, there is a growing demand for surfaces to be as uniform as possible.

[0009] Furthermore, when leveling the concrete surface with a rotary trowel, the concrete surface is still damp. Therefore, when the damp concrete surface is pressed with a rotary trowel, the pressure causes moisture to seep out of the concrete, resulting in a slightly higher moisture content on the surface. The rotating blade of the rotary trowel then scrapes off the moisture-rich portion of the concrete surface. This scraped-off, moisture-rich portion contains almost no aggregate, resulting in a mortar-like paste. We will refer to this paste as "concrete paste."

[0010] The concrete paste scraped off by the rotating blade of the rotary trowel is scattered around the rotating trowel head by the centrifugal force of the blade. In other words, concrete paste is scattered onto the surface of the concrete leveled by the rotary trowel, and the flatness of the concrete surface is reduced as a result of the amount of scattered concrete paste that forms bumps on the concrete surface.

[0011] Therefore, under normal circumstances, a rotary trowel is used for trowel finishing to minimize the scattering of concrete paste, that is, to create a condition where concrete paste is less likely to form by ensuring the concrete surface is relatively hard. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2007-100426 [Overview of the project] [Problems that the invention aims to solve]

[0013] As mentioned above, the surface of concrete finished with a rotary trowel is wavy, and there was a problem in that it was not possible to effectively and efficiently address the requirement for a flat surface that eliminated such wavyness.

[0014] The present invention aims to provide a construction method that enables the construction of a concrete floor slab with a more flat surface by utilizing the concrete paste generated by using a rotary trowel in the construction of a concrete floor slab using a rotary trowel. [Means for solving the problem]

[0015] The present invention relates to a concrete floor construction method comprising a concrete pouring step of pouring concrete, a leveling step of leveling the surface of the poured concrete using a rotary trowel, and a leveling step of pressing a leveling plate against the surface of the concrete after the leveling step to correct any unevenness. In the leveling step, concrete paste is generated on the surface of the concrete by operating the rotary trowel, and in the leveling step, the concrete paste is spread on the surface of the concrete using a leveling plate.

[0016] Furthermore, the concrete floor construction method of the present invention is also characterized in that the leveling plate is at least 1.5 times the rotational diameter of the rotary trowel, and that more than 50% of the surface of the concrete leveled with the rotary trowel is covered with the concrete paste generated in the leveling process. [Effects of the Invention]

[0017] According to the present invention, by using a rotary trowel to generate concrete paste on the surface of the concrete and spreading this concrete paste on the surface of the concrete, the wavy surface of the concrete created by the rotary trowel can be made flat, making it possible to construct a concrete floor with a highly flat surface. [Brief explanation of the drawing]

[0018] [Figure 1] It is a schematic explanatory view of a rotary trowel used in the leveling process. [Figure 2] It is an explanatory view of a leveling plate used in the leveling process.

Embodiments for Carrying Out the Invention

[0019] The construction method of the concrete floor of the present invention includes a placing process of placing concrete, a leveling process of leveling the surface of the placed concrete using a rotary trowel, and a leveling process of pressing a leveling plate against the surface of the concrete after the leveling process to perform unevenness correction. The inventor of the present invention refers to the construction method of the present invention as the "JSN construction method".

[0020] In addition, between the placing process and the leveling process, there is a leveling process of confirming that the surface of the placed concrete has reached a predetermined height specified in the design drawing. In the placing process, the surface of the concrete is leveled to such an extent that this leveling can be performed.

[0021] In the leveling process, the surface of the concrete is leveled by operating a rotary trowel. As schematically shown in FIG. 1, the rotary trowel 10 has a rotary float portion 13 in which a blade 12 serving as a float is attached to a rotary arm 11 that is rotationally driven substantially horizontally, and a handle arm 14 extending obliquely upward from this rotary float portion 13 is provided. Instead of the plate-shaped blade 12, a disk having a circular shape equivalent to the rotation locus of the blade 12 may be attached to the rotary arm 11. That is, it is a disk-shaped float. In terms of the generation of the concrete paste described later, this disk-shaped float is superior because it is always in contact with the concrete.

[0022] In the rotating trowel part 13, it has a circular frame 15 in a plan view with its central part bulging upward. A stage 16 is provided at the central part of this frame 15, and a driving engine 17 etc. are arranged on this stage 16. The output shaft (not shown) of the driving engine 17 is provided vertically downward and is interlockingly connected to a rotating shaft 18 that penetrates the stage 16. The rotating shaft 18 is provided in the vertical direction. A plurality of rotating arms 11 are radially provided on the rotating shaft 18 in the horizontal direction, and blades 12 are respectively attached to each rotating arm 11. Or a disk-shaped trowel is attached. A handle bar 19 for an operator to grip is provided on the handle arm 14 as an operation handle, and the rotary trowel 10 is to be towed and operated.

[0023] In the leveling process, the surface of the concrete is leveled using a floor construction machine 20 equipped with a leveling plate 21 shown in FIG. 2. The floor construction machine 20 of the present embodiment has a rectangular frame-shaped base frame 22, and the leveling plate 21 is attached to the rear end of this base frame 22. On both the left and right sides of the base frame 22, connecting plates 23, 23 protruding upward are provided respectively. Both ends of an operation handle 24 shaped like a U in a plan view are rotatably attached to these connecting plates 23, 23 respectively, and the leveling plate 21 can be towed through the base frame 22.

[0024] Note that as another embodiment, the operation handle 24 may be rotatably connected to the leveling plate 21. In particular, the leveling plate 21 is not limited to a long and thin plate, and an appropriate flat plate can be used. Here, the "flat plate" means a "plate that forms a flat surface by scraping the surface of the concrete". Therefore, the leveling plate 21 may be a material having elasticity such as foamed urethane, etc. Specifically, a sponge-like material called AOI Elastite (registered trademark) of Aoi Kogyo Co., Ltd. was suitable.

[0025] In the floor construction machine 20 of this embodiment, the base frame 22 is provided with a lifting mechanism 25 for moving the leveling plate 21 up and down, and the leveling plate 21 is detachably attached to the support frame 26 of the lifting mechanism 25 by a plurality of mounting screws 27. The mounting screws 27 have a ring-shaped rotating operating piece attached to one end of the male screw so that the mounting screws 27 can be handled without using a wrench. In the floor construction machine 20 of this embodiment, leveling plates 21 of different lengths and shapes can be appropriately replaced, and the desired leveling plate 21 is attached to the support frame 26 with mounting screws 27. An L-shaped angle 28 is attached to the leveling plate 21, and the leveling plate 21 can be detachably attached to the support frame 26 via the L-shaped angle 28 and the mounting screws 27.

[0026] Furthermore, in the floor construction machine 20 of this embodiment, skid plates 31, 31 are attached to the bottom surface of the base frame 22, allowing the base frame 22 to slide on the concrete surface with relatively little force. The skid plates 31 are attached to a support frame 33 that is suspended from two intermediate frames 32, 32 which are erected inside the base frame 22. In this embodiment, two skid plates 31, 31 are mounted side by side.

[0027] The floor leveling machine 20 performs leveling of uneven surfaces using the leveling plate 21 by pulling it with the operating handle 24. At the same time, the lifting mechanism 25 lifts the leveling plate 21, separating it from the concrete surface. In this state, the base frame 22 can also be moved in the opposite direction to the pulling direction using the operating handle 24. The lifting mechanism 25 also adjusts the angle of attack of the leveling plate 21.

[0028] The essential parts of the present invention will be described below.

[0029] After the leveling process, workers wear special assistive devices on their feet to walk on the still-wet concrete and check its moisture level. These assistive devices are special slippers with a contact area approximately 1.5 times larger than that of boots, and can be worn while wearing boots.

[0030] In this embodiment, it has been confirmed that when walking on concrete while wearing the assistive device, the concrete becomes hard enough to sink by approximately 1 to 5 mm. This hardness will be referred to as the "work start hardness."

[0031] After confirming that the concrete has reached the starting hardness for the work, the leveling process is carried out using a rotary trowel 10. Note that the starting hardness is softer than the concrete hardness required for the conventional leveling process using a rotary trowel 10. For reference, the concrete hardness required for the conventional leveling process using a rotary trowel 10 is such that when walking on it with boots, the boots do not sink in, but rather leave an imprint.

[0032] In this leveling process, the semi-dry concrete is leveled with the rotary trowel 10, scraping off the surface of the concrete with the blade 12 or disc-shaped trowel of the rotary trowel 10 to generate concrete paste, and scattering the generated concrete paste around the rotary trowel part 13 of the rotary trowel 10.

[0033] The degree of concrete paste scattering should ideally be such that it covers 50% or more of the surface of the concrete leveled by the rotary trowel 10. Furthermore, it is desirable to adjust the rotation speed of the rotary shaft of the rotary trowel 13 and the angle of attack of the blade 12 so that the maximum scattering distance of the concrete paste is approximately the length of the blade 12 from the outer end of the blade 12 of the rotary trowel 13 in the longitudinal direction.

[0034] If the concrete is not sufficiently covered with concrete paste, the amount of backward movement of the rotary trowel 13 is adjusted by adjusting the amount of backward movement of the worker when moving backward. In addition, at the edges of the concrete being leveled by the rotary trowel 10, it may be difficult to move the rotary trowel 10, making it difficult to scatter the concrete paste sufficiently. In such cases, the rotary trowel 10 is moved forward and backward, or the rotary trowel 10 is moved towards the edges of the concrete to scatter as much concrete paste as possible.

[0035] This leveling process also ensures that a predetermined amount of concrete paste is evenly distributed across the surface of the concrete.

[0036] After the leveling process, a leveling process is performed using a floor construction machine 20. In this leveling process, a leveling plate 21 attached to the floor construction machine 20 is pressed against the surface of the concrete to level out any unevenness. In particular, the leveling plate 21 spreads and smooths the concrete paste that has been scattered on the surface of the concrete.

[0037] This leveling process allows the depressions in the uneven surface formed on the concrete surface during the leveling process with the rotary trowel 10 to be filled with concrete paste, thereby improving the flatness of the concrete surface. Furthermore, because the concrete surface is not completely hardened, the leveling effect of the floor construction machine 20 can be obtained, further improving the flatness of the concrete surface.

[0038] Here, it is desirable that the leveling plate 21 be at least 1.5 times the length of the rotation diameter of the rotating trowel part 13 of the rotary trowel 10. The rotation diameter of the rotating trowel part 13 is the diameter of the circle that forms the rotational trajectory of the outer edge of the blade 12 of the rotating trowel part 13.

[0039] In other words, by making the longitudinal length of the leveling plate 21 1.5 times or more the rotation diameter of the rotating trowel part 13, the leveling plate 21 can be positioned in a near-horizontal position, making it possible to not only flatten the concrete surface but also create a flat surface that is close to a horizontal plane.

[0040] Preferably, the length of the leveling plate 21 in the longitudinal direction is 2.5 to 3.5 times the rotation diameter of the rotating trowel part 13. This is a balance between the leveling effect of the leveling plate 21 and the ease of handling of the floor surface construction machine 20.

[0041] Thus, in this invention, the flatness of the concrete surface can be improved by effectively utilizing the concrete paste formed by using the rotary trowel 10. [Explanation of Symbols]

[0042] 10 Rotary Trowels 11 Rotating Arm 12 blades 13 Rotating trowel section 14 Handle Arm 15 frames 16 stages 17. Drive engine 18 rotation axes 19 Handlebars 20 Floor construction machine 21 leveling board 22 Base Frame 23 Connecting plate 24 Operating handles 25 Lifting mechanism 26 Support frame 27 Mounting screws 28 L-shaped angle 31 Sled 32 intermediate frames 33 Support Frame

Claims

1. The concrete pouring process, A leveling step in which the surface of the poured concrete is leveled using a rotary trowel, A leveling step is performed by pressing a leveling plate against the surface of the concrete after the leveling step to correct any unevenness. In a construction method for a concrete floor slab having the following characteristics: In the leveling process, concrete paste is generated on the surface of the concrete by operating the rotary trowel. In the leveling step, the concrete paste is spread and leveled on the surface of the concrete using the leveling plate in the concrete floor construction method.

2. The method for constructing a concrete floor according to claim 1, wherein the leveling plate is at least 1.5 times the rotational diameter of the rotary trowel.

3. The method for constructing a concrete floor according to claim 1 or claim 2, wherein the concrete paste generated in the leveling step covers 50% or more of the surface of the concrete that has been leveled with the rotary trowel.

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