WO2022210682A1

WO2022210682A1 - Method for constructing concrete floor

Info

Publication number: WO2022210682A1
Application number: PCT/JP2022/015367
Authority: WO
Inventors: 雄二又吉
Original assignee: 株式会社フロアエージェント
Priority date: 2020-03-27
Filing date: 2022-03-29
Publication date: 2022-10-06
Also published as: JP7072955B2; JP2021156158A; JP2022024180A

Abstract

The present invention provides a method for constructing a concrete floor that can achieve a high level accuracy, cracking reduction, and durability.　This method for constructing a concrete floor includes: a first step S1 for placing concrete on a floor of a construction site; a second step S2 for leveling concrete floor 10 by a laser screed machine 30; a third step S3 for confirming the level of the concrete floor 10 leveled by the laser screed machine 30; and a fourth step S4 for performing re-vibration compaction when a predetermined time has passed after confirming the level of the concrete floor 10, the re-vibration compaction being performed on the basis of a bleeding measurement result by a bleeding measurement device.

Description

Concrete floor construction method

The present invention relates to a construction method for concrete floors constructed in various civil engineering and construction works, particularly to a construction method for concrete floors of buildings such as warehouses.

Conventionally, construction methods for concrete floors of buildings such as warehouses are publicly known. When constructing a concrete floor, ready-mixed concrete, which is a mixture of cement, aggregate, water, and various admixtures in appropriate proportions, is hardened through construction such as pouring, compaction, surface finishing, and curing. . After leveling the concrete surface to make it smooth, the floor surface is evenly pressurized using a floor surface finishing device such as Trowell to flatten it, and if necessary, a skilled plasterer Finishing is done manually with a trowel (plastering trowel), and the surface of the concrete is finished so that it has a glossy surface.

For example, Patent Document 1 discloses a method for finishing a floor surface after pouring concrete. As a second step, after the concrete floor surface after tamping has completely hardened, the concrete floor surface is directly ground with a grinder to complete the floor finish.

JP-A-6-173453

In the concrete floor construction method disclosed in Patent Document 1, the plastering work is performed by machines instead of the conventional manual work by plasterers, so that the difference in finishing level occurs depending on the skill level of the plasterers. In addition, it is possible to shorten the working time and reduce the cost.

However, in order to achieve high level accuracy, crack suppression, and durability of the concrete floor surface according to the client's request (specifically, it can be said that hard concrete with a slump value of 15 or less is essential) In addition to mechanizing all the work from leveling the concrete to finishing, it is necessary for the concrete to have a predetermined strength in each process.

The present invention is an improvement of the conventional concrete floor construction method, and aims to provide a concrete floor construction method that can achieve high level accuracy, crack suppression, and durability.

In order to solve the above problems, the present invention relates to a concrete floor construction method.

A concrete floor construction method according to the present invention includes a first step of placing concrete on the floor of a construction site, and a second step of leveling the concrete floor with a laser screed machine. and a fourth step of performing re-vibration compaction after a predetermined time has elapsed after confirming the level of the concrete floor, wherein the re-vibration compaction Hardening is the time when bleeding occurs when water lines begin to be formed, and the time when the depth dimension of accumulated water is 40 to 60% of the depth dimension of the holes formed in the concrete floor surface. It is characterized by performing with

The concrete floor construction method according to the present invention includes the following embodiments.
(1) The laser screed machine has a vibrating blade and a mortar plate located in front of the vibrating blade, and the length dimension of the mortar plate is larger than the length dimension of the vibrating blade.
(2) Further comprising a fifth step of surface finishing the concrete floor surface by means of rotary discs of a first rotary drive machine, wherein the rotary discs include a pair of discs, and behind the pair of discs there is no waste. A land adjusting means is located, the length dimension of the unevenness adjusting means is larger than the length dimension of the pair of discs, and the unevenness adjusting means is brush-shaped.
(3) Further includes a sixth step of finishing the concrete floor surface with a vane-shaped rotary trowel of the second rotary drive machine, and the surface finish in the fifth and sixth steps is measured by a penetration test in accordance with JISA1147. Values are performed between 0.5N and 2.7N.
(4) The first and second rotary driving machines have a hand-held type and a riding type, and the surface processing by the riding-type first rotary driving machine has a measured value between 1N and 2.1N. , the surface finishing by the riding-type second rotary drive is carried out while the measured value is between 2.5 and 2.7N.

In the concrete floor construction method according to the present invention, re-vibration compaction is performed at the time when bleeding occurs, thereby suppressing cracking and obtaining a concrete floor with excellent durability.

The drawings show specific embodiments of the concrete floor construction method according to the present disclosure, and include not only the essential components of the invention, but also optional and preferred embodiments.
The figure of the flowchart which shows the procedure of the construction method of the concrete floor which concerns on this invention. The figure which shows the mode of the placement leveling work in a 1st process. The figure which shows the mode of a laser screed leveling in a 2nd process. The figure which shows the mode of level confirmation of a floor surface in a 3rd process. (a) The figure which shows the mode of the re-vibration compaction work in a 4th process. (b) A diagram showing a state during work for confirming bleeding. (a) A diagram showing a hand-type Trowel disc setting work in the fifth step. (b) A diagram showing a riding-type Trowel disc setting work in the fifth step. (a) A diagram showing a state of hand-type trowel feather pressing work in the sixth step. (b) A diagram showing a riding-type trowel blade pressing operation in the sixth step. The figure for demonstrating the bleeding measurement inside a concrete floor. (a) An external configuration diagram of a bleeding measuring device according to the present embodiment. (b) A diagram for explaining bleeding measurement inside a concrete floor using a plurality of bleeding measuring devices. (a) and (b) are external configuration diagrams of a bleeding measuring device showing a modification of FIG. 9(a). (a) A diagram showing measurement results using a bleeding measurement device (ambient temperature 10°C). (b) A diagram showing measurement results using a bleeding measurement device (ambient temperature 35°C).

The details of the construction method for the concrete floor surface 10 according to the present invention are described below with reference to the attached drawings. In addition to the essential requirements of the present invention, the following embodiments also include requirements that can be selectively adopted and requirements that can be combined as appropriate.

<First step (concrete leveling work) S1>
Referring to FIG. 2, in the first step S1, reinforcing bars are installed at a location where a concrete floor surface 10 is to be constructed in a construction site such as a warehouse, and then ready-mixed concrete is poured by a concrete pump vehicle. Concrete pumped from the pipe of a pump car is roughly leveled using a scraper or the like. Before placing the fresh concrete, various tests such as a slump test, an air content test, and a chloride content test are conducted to confirm the properties of the fresh concrete.

In the first step according to the present invention, compaction work is performed by inserting the rod-shaped vibrator 20 into the fresh concrete. In addition, in order to sufficiently compact the concrete, it is important to appropriately determine the insertion interval of the rod-shaped vibrator 20, the vibration time per insertion point, and the timing of pulling out the rod-shaped vibrator 20. , the insertion interval of the rod-shaped vibrator 20 is 40 to 60 cm, and the vibration time at one insertion point is 10 to 20 seconds. By thus determining the insertion interval, vibration time, and withdrawal timing of the rod-shaped vibrator 20, the concrete floor surface 10 can be sufficiently compacted, and when the rod-shaped vibrator 20 is gradually withdrawn, the concrete floor surface No holes are left at the point where 10 is withdrawn.

<Second step (laser screed leveling) S2>
As shown in FIG. 3, in the second step S2, after rough leveling by the rod-shaped vibrator 20, automatic floor leveling of the placing surface by an automatic leveling machine is performed. As the automatic leveling machine, a commercially available one can be appropriately selected and adopted. For example, a laser screed machine (concrete leveling machine "Mini Screed C" manufactured by Somero, USA) 30 can be used. In the laser screed machine 30, the vibrating shaft is rotated at high speed to vibrate the vibrating blade 36 in plane, thereby filling and compacting the concrete.

The laser screed machine 30 has

support rods

32 and 33 facing each other in the width direction, and

laser receivers

32a and 33a are positioned at the tips of the

support rods

32 and 33, respectively. A laser emitter 34 having a laser irradiation part is arranged near the laser screed machine 30, and the level of the concrete floor surface 10 is leveled by automatic level adjustment means comprising the laser emitter 34 and

laser receivers

32a and 33a. I am watching. The laser screed machine 30 includes a screed plate (scrape bar) 35 for scraping the concrete floor 10, and a vibrating blade 36 positioned in front of the screed plate for applying plane vibration to the concrete floor 10 by a vibrator to level the surface. and Cracking of the concrete floor surface 10 can be suppressed by removing air bubbles and air in the concrete by vibration tamping with a vibrator and increasing the density of the concrete.

In conjunction with the automatic level adjustment means, the screed plate 35 scrapes the concrete floor surface 10 and the vibrating blade 36 tamping due to plane vibration. That is, the laser screed machine 30 has a laser level measuring function by the automatic level adjusting means, a concrete scraping function by the screed plate 35 driven in conjunction with the automatic level adjusting means, and a tamping function in which the vibration is associated with the automatic level adjusting means. Prepare.

In this way, the laser screed machine 30 advances in the direction of travel while the automatic level adjustment means checks the horizontal level of the placing surface, so that the operator can always check the level and work while maintaining a stable level. can be done. Therefore, by performing automatic floor leveling with the laser screed machine 30 instead of the leveling work that has been done manually by the conventional plasterer, unevenness can be reduced, the level can be made uniform, and workability can be improved. A dense concrete can be achieved by the tamping effect of the vibration of the vibrating blade 36 .

In addition, the laser screed machine (mini screed C) 30 can perform rough leveling, leveling, tamping, and screed work with one machine, and has a function to prevent defects due to reflection of unnecessary light rays during level measurement, Equipped with an extremely high-performance laser level, such as a function that can accurately measure the water slope, an automatic level correction function, and a remote control level setting. When using the laser screed machine 30, it is preferable to receive guidance from a professional instructor in order to realize safe work at the work site and stable level accuracy of the placing surface. In addition, in a place where there are obstacles such as pillars, in addition to the work by the laser screed machine 30, it is preferable to use manual work by a worker.

As a configuration not provided in conventional laser screed machines, the laser screed machine 30 according to this embodiment has a mortar board 37 on the concrete floor surface 10 attached in front of the vibrating blade 36 . Due to the position of the mortarboard 37, the unevenness formed on the surface of the concrete floor surface 10 after the raking and tamping operations can be finally erased by the mortarboard 37.

The length dimension W1 of the mortar plate 37 is larger than the length dimension W2 of the vibrating blade 36. Due to the correlation between the length dimensions W1 and W2, the unevenness of the concrete floor surface 10 can be reliably eliminated. In this way, by additionally providing the mortar plate 37 to the laser screed machine 30, in addition to the conventional laser level measurement function, concrete scraping function, and tamping function, a finishing trowel function is added, so that the concrete can be cut more completely. Leveling work can be performed.

In addition, since the laser screed machine 30 has been developed for traveling with reinforcing bars, it is designed so that no load is applied to the reinforcing bars, mesh, etc. during traveling. A wide tire width of 200 mm is secured to prevent damage to the reinforcing bars during construction, and the weight is distributed, so that the reinforcing bars are not distorted, bent, or disturbed. In addition, since it is designed with a load of about 220 kg, which is the lightest among similar automatic floor leveling machines, during construction, the load per point is distributed by three points including the tires of both wheels and the front part. is around 70kg to 90kg (two-point load during running), which enables stable automatic floor leveling work.

<Third step (floor surface level confirmation) S3>
Referring to FIG. 4, in the third step S3, after automatic floor leveling by the laser screed machine 30, the auto level 40 is used to check the level of the concrete floor surface 10 at a pitch of 2000 mm. Further, in the vicinity of the outer edge of the concrete floor surface 10 and the portion where the pillars of the building are located, confirmation work is performed at intervals of 500 to 1500 mm in order to accurately confirm the level.

<Fourth step (re-vibration compaction) S4>
Referring to FIGS. 5(a) and 5(b), in the fourth step S4, after the level of the concrete floor surface 10 has been confirmed and a predetermined time has elapsed, at the time when bleeding occurs, a floor compaction machine (flat tamper machine ) 50 performs re-vibratory compaction to remove air bubbles and voids. By performing re-vibration compaction, it is possible to expel the water that has accumulated under the reinforcing bars and aggregates due to bleeding, improve the adhesion of the concrete to the reinforcing bars and aggregates, and increase the strength of the concrete.

Referring to FIG. 5(b), bleeding is performed by inserting a finger into the concrete floor surface 10 and pulling it out in the same manner as in the conventional art, and pouring water into a hole 52 formed in the concrete floor surface 10 where the finger is pulled out. This can be confirmed by the accumulation of 53. In this embodiment, in order to accurately check the bleeding, the checking work is performed by inserting a finger into five places at intervals of 1 m.

　Conventionally, before bleeding or after a while, it was enough to just hang the dragonfly or vibrate with a rod-shaped vibrator, and did not re-vibrate and compact immediately after confirming the bleeding. However, if bleeding occurs, it is clear that water mites are formed inside the concrete. face could not be formed. Further, if vibration is applied again after bleeding has occurred completely, it interferes with the setting of the concrete due to the hydration reaction, making it impossible to form a strong concrete floor surface.

In the concrete floor construction method according to this embodiment, when bleeding occurs, tamping vibration is firmly applied using a flat tamper machine to remove air bubbles and voids caused by water mites, and finally a strong floor without cracks. A concrete floor surface can be formed. Here, the "time point when bleeding occurs" means the time point when it is confirmed that the formation of a water line has started. Specifically, in FIG. , when the depth dimension D2 of the pooled water 53 is 40 to 60%, preferably 45 to 55%. By applying plane vibration by the floor surface compactor 50 at such timing, it is possible to reliably remove air bubbles and voids caused by water dust.

In addition, according to the applicant's knowledge, "the point at which bleeding occurs" is the golden time that can be said to be the most suitable time for re-vibration between before and after setting of concrete, and cracks do not occur after construction. It can be said that this is one of the most important points for obtaining a strong concrete floor surface 10 . In other words, this timing is within a range in which quality uniformity can be obtained in terms of the compressive strength ratio and density ratio of the concrete floor surface, and can be said to be the optimal re-vibration compaction time for improving the quality of concrete.

The applicant further improved the construction method in order to improve the quality (performance) of the concrete floor. Specifically, in order to accurately confirm bleeding, we developed a bleeding measurement device that measures the timing of occurrence of bleeding. This bleeding measuring device is a measuring instrument for assessing the state of concrete by looking at the water volume based on the water content of the concrete.

As shown in FIG. 9A, the bleeding measuring device 70 includes a wireless communication unit 71 with a built-in power supply (not shown), a water surface detector (water surface detection sensor) 72 connected to the wireless communication unit 71, and a measuring unit. 73. The power source of the wireless communication unit 71 is preferably a small power source such as a small lithium button battery, AAA dry battery, alkaline battery, AAA dry battery or alkaline battery. This is because a small and lightweight measuring device is suitable for measuring bleeding inside a concrete floor. The wireless communication unit 71 can use Bluetooth (registered trademark), wifi, etc., which are capable of short-range wireless communication.

The measurement unit 73 is composed of a measurement container 74, a mesh filter 75 provided on the outer skin of the measurement container, and an insertion port 76 (cylindrical) into which the water surface detector 72 is inserted. Since the measurement unit 73 is used by directly inserting it into the cast fresh concrete, a plurality of slits and holes (or holes) are provided in the measurement container 74 so that the water seeping out from the inside of the fresh concrete is accumulated in the measurement container 74 . ing. Furthermore, the entire measuring container 74 is covered with a mesh filter 75 to prevent mud, gravel, etc. from entering the measuring container 74 . A transparent acrylic material or the like can be used for the measurement container 74 . The mesh filter 75 is made of nylon and has a bag shape. It is welded so as to cover the entire measurement container 74 . The water surface detector 72 is provided with a detachable flange, is inserted into the pipe of the measurement container 74 from the insertion port 76, and is positioned at a predetermined position within the pipe. The flange 77 is a C-shaped resin material having a notch (opening) in part. When the water level detector 72 is inserted into the insertion port, the flange 77 is bent inward, applying a pressing force to the pipe wall and positioning the detector. be done.

We conducted a mesh filter selection experiment. The mesh filters of #100 to 300 were judged to be unsuitable because the cement was turbid and the cement was judged to be permeated. In addition, the #400 and #500 mesh filters were judged to be suitable (usable) because there was no turbidity in the cement and they did not permeate.

A trial experiment was conducted to confirm the tube hole position and tube size of the measurement container. The water level of the hole in the side varies depending on the depth of insertion into the ready-mixed concrete, making it difficult to use as a measuring instrument. Consideration is advanced with a hole to the bottom. As a result of examining the minimum hole diameter, it was determined that the smaller the hole diameter, the better the penetration resistance (surface tension), and the closer the measurement to the dry state of concrete.
Hole diameter 3 mm → penetration hole diameter 1 mm → penetration Since both are permeable, it was judged that the hole diameter was suitable (usable) if it was in the range of 1 mm to 3 mm. Confirmation of the water level data was performed with a hole diameter of 1 mm in the measurement container.

From these experimental results, a #500 filter was used as the bleeding measuring device, and the hole diameter of the measuring container was 1 mm.
Concrete water content → cement 1: sand 3 (volume ratio of water 40% to 45%)
An experiment was conducted by submerging a 100 mm-high tube of a measurement container by 90 mm. The experimental results are shown in FIG.

The timing of using the bleeding measurement device is the time after the concrete is poured until it is re-vibrated, and the results so far have been around 20 minutes in the summer and around 40 minutes in the winter.

As shown in FIG. 8, after the driving is finished, the measuring part 73 is inserted into the ready-mixed concrete (ready-mixed concrete) by 90 mm (D1), and when the water level in the inner pipe reaches X mm (D2), vibration is performed again. Regarding X mm, the target value (X) is changed according to the outside air temperature. FIG. 11(a) shows the results of measurement using the bleeding measuring apparatus of FIG. 9(a) in an environment with an ambient temperature of 10° C. (assuming a winter environment). Also, FIG. 11(b) shows the results of measurement using the bleeding measuring apparatus of FIG. 9(a) in an environment with an ambient temperature of 35° C. (assuming a summer environment). In the examples of FIGS. 11(a) and 11(b), the elapsed time after pouring ready-mixed concrete (in the experimental environment) was measured every 5 minutes from 0 to 60 minutes. Moisture content was measured at 40% and 45%. From the results of FIGS. 11(a) and 11(b), it can be said that in winter, it is sufficient to start the vibration again when the water level is reached in about 45 minutes or less. Also, in the summertime, it can be said that it is sufficient to start the vibration again when the water level corresponding to the water content is reached in about 25 minutes or less.

As shown in FIG. 9(b), it is also possible to divide the concrete floor surface into areas, install a plurality of bleeding measuring devices 70a to 70h for each section, and automatically detect the timing of bleeding through wireless communication. As a result, the entire concrete floor surface can be appropriately re-vibrated.

　Figures 10(a) and 10(b) show another example of the bleeding measuring device. The example of FIG. 10(a) shows an example in which a hole 78 is provided in the bottom surface of the measurement container. The example of FIG. 10B shows an example in which a hole 78 is provided in the bottom surface of the measurement container and a partial mesh filter 79 is provided without the mesh filter 75 . In FIG. 10(b), a scale for positioning is further provided on the outside of the measurement container, a mark 81 for position adjustment is provided on the side surface of the flange 82, and an opening 83a is provided for a push-in portion 83 such as a syringe and a cable for the water surface detection sensor. It has a structure drawn from

By adopting such a configuration, the water surface height adjustment is simplified.

<Fifth Step (Trouwel Disc Hanging) S5 and Sixth Step (Trouwel Feather Retainer) S6>
Referring to FIGS. 6(a), (b) and FIGS. 7(a) and (b), after leveling the concrete floor surface 10 by re-vibration, the trowell (rotary driving machine, surfacing machine) 61-64 , the concrete floor surface 10 is evenly pressurized and flattened. Trowells 61-64 are available in two types: hand type operated by the operator while walking and riding type operated by riding on the main body of Trowel. It is a floor surface finishing machine that finishes the concrete floor surface 10 before. A hard steel plate such as SK material or high-strength steel is suitably used for the rotary disk and vane-shaped rotary iron.

For the trowel 61-64 used in this construction method, a known one can be used, but it is a hand-held type (hand type) that alternately rotates the rotary disc so as to adjust unevenness and even out unevenness. Alternatively, it is preferable to use horse-riding trowels (disc holders) 61 and 62, hand-held trowels (blade holders) 63 having metal vane-shaped rotary trowels, and horse-riding trowels 64 having metal vane-shaped rotary trowels in this order. .

That is, after flattening the concrete floor surface 10 to some extent while adjusting the rotation direction and the number of rotations of hand-held or riding-type trowels (disc holders) 61 and 62, hand-held trowels having a metal vane-shaped rotary trowel ( The blade presser) 63 is rotated alternately on the vertical axis and the horizontal axis, and the finishing work is carefully performed at a constant speed while adjusting unevenness and unevenness until the concrete floor surface 10 shines slightly. .

To move Trowel 61-64, the handle lever attached to the Trowel body is operated up and down to tilt the Trowel body and change the ground pressure on the rotating surface of the rotating trowel, using the thrust generated by the difference in ground resistance. can be done by In this way, when the trowels 61-64 are moved, the trowel body is tilted and uneven contact pressure is applied to the rotating surface of the rotating trowel. , Finally, a detailed metal trowel finish by a plasterer is required.

Usually, after hardening the surface of the concrete floor with a relatively heavy horse-riding trowel, the surface is processed with a relatively lightweight hand-type trowel and trowel work is performed. In this construction method, as will be described later, after the hand-held trowel (disc hanger) 61 is used once to hang the discus, after a predetermined period of time, the discus hanger is carried out multiple times by the horse-riding trowel (disc hanger) 62. Furthermore, after holding down the hand-held trowel (wing hook) 63 once, holding down the riding-type trowel (wing hook) 64 is performed multiple times after a predetermined time interval. Striped trowel marks are less likely to be left, and the work load of iron trowel finishing can be reduced.

Referring to FIGS. 6(a) and 6(b), the hand-type rotary disc 61 and the riding-type rotary disc 62 according to the present embodiment have a configuration not included in conventional rotary discs. Brush plates (unevenness adjusting means) 65 and 66 are arranged behind the pair of

discs

61a and 62a.

In this way, unevenness can be adjusted by removing unevenness on the concrete floor surface 10 with the

brush plates

65 and 66 immediately after the

disks

61a and 62a of the rotary disk are applied. Further, the lengths W3, W5 of the

brush plates

65, 66 located behind the pair of

discs

61a, 62a of the hand-held or riding type trowells (disc hooks) 61, 62 are longer than the lengths W4, W6 of the pair of discs 61a, 62a. is larger. Since the length dimensions W3 to W6 have such a correlation, it is possible to reliably remove unevenness in the disc-covered portion. The

brush plates

65 and 66 are unevenness adjusting means, and the brush portions may be comb-shaped or flat-plate-shaped, but they are different in structure and function from the mortar plate for surface finishing. .

<Seventh step (finishing with iron trowel) S7>
After the trowel work is done by Trowel, if necessary, the trowel finish is done by the plasterer.

<Eighth step (curing) S8>
After the surface pressurization by the Trowells 61-64, it is important to supply moisture to the concrete floor 10 in order to promote a sufficient hydration reaction and prevent surface cracks due to drying. For that purpose, water curing and moist curing are performed for the required number of days according to the average daytime temperature. In this construction method, it is preferable to perform water curing and wet curing for at least 7 days. In addition, by performing curing in about three days after finishing with a trowel, it is possible to suppress the occurrence of cracks on the surface of the concrete floor surface 10 even in a dry air state.

<Penetration test of concrete floor>
A penetration test was performed on the concrete floor surface 10 during any one of the steps S1 to S8. In particular, in order to maintain and improve the impact resistance, wear resistance, and durability of concrete floors 10 for distribution warehouses, initial vibration, re-vibration and surface pressure due to compaction effect Process is considered important. The purpose of this test is to quantitatively standardize the surface pressure timing of the hand-held

trowels

61 and 63 and the riding trowels 62 and 64 in the surface processing (fifth and sixth steps S5 and S6). As such, it was carried out under the following conditions.

Test location: Inside a domestic logistics warehouse with a site area of ^20,000m2

Construction method: This construction method (LCS construction method)

　Tester: Hydraulic Proctor Penetration Tester S06

　Test method: conforms to JISA1147

　Concrete slump value: 8-15

Admixture: Fluidizer

Warehouse temperature: 10.4°C
Humidity in warehouse: 55%

<Test method>
A sample (sample 1) was taken from the placed concrete floor surface 10, and a concrete setting test in accordance with JISA1147 was performed. Specifically, the test was conducted in the following procedure.

Sample 1 was collected in accordance with JISA1138 or JISA115. Next, Sample 1 was screened through a mesh sieve of about 5.0 mm specified in JISZ8801-1 to obtain a mortar portion (Sample 2). The temperature of Sample 2 was measured according to JISA1156.

Sample 2 was kneaded with a hand shovel to make it sufficiently uniform, and placed in a container in one layer so that it was almost symmetrical with the axis of the container. The upper surface of Sample 2 placed in a container was leveled with a poking rod, and the poking was performed once per about 1000 mm. However, if there was a risk of separation of the material when poked at such a rate, the number was reduced to the extent that separation did not occur. After piercing, the side of the container was lightly tapped to eliminate the piercing hole, and the upper surface was flattened so that it was about 10 mm lower than the upper end of the container. The surface of the sample 2 is preferably flattened with a trowel so as to obtain a smooth surface with minimal work.

Place the container containing sample 2 on a horizontal table or floor that does not vibrate, and cover it with an appropriate lid to prevent moisture from evaporating from the container. The lid was kept on at all times during the test except when blotting the bleeding water and when performing the penetration test. If there was bleeding water, the bleeding water on the surface of Sample 2 was sucked up with a pipette or other suitable device just prior to conducting the penetration test. When removing the bleeding water, about 2 minutes before the penetration test, a block or the like having a thickness of about 30 mm was sandwiched on one side of the bottom of the container and the container was carefully tilted. After removing the bleeding water, the container was returned to its original state, being careful not to shake it.

Next, a penetration needle with an appropriate cross-sectional area was selected according to the hardening state of Sample 2, and attached to the penetration resistance test device. The penetrating needle was carefully penetrated vertically downward into sample 2 by approximately 25 mm. The depth of penetration was confirmed by markings on the penetration needle. The time required for penetration was about 10 seconds.

The time when the penetration test was performed and the force (N) required for penetration were read from the device and recorded. During penetration, care was taken to avoid penetrating areas that were disturbed in the previous penetration test. The net spacing of the needle traces of the penetrating needle was about twice the diameter of the penetrating needle used and 15 mm or more. Also, the net distance between the penetration needle and the side surface of the container was set to 25 mm or more.

Table 1 below shows the results of the penetration test conducted based on the above test conditions and test method.

As shown in Table 1 above, each step S1-S7 was performed at a predetermined timing. The time of pouring water was set as the start time, and the hand-held trowell 61 was applied to the disk at 0.5 N, which is the time when the concrete floor surface 10 spontaneously set and the operator could climb up with slippers. Three hours and five minutes had passed since the injection of water, and the work was carried out for about 40 minutes. Discus hooking by a horse-riding Trowel 62 was performed four times between 1.0N and 2.1N. Three hours and 40 minutes had passed since the injection of water, and the work was carried out for 2 hours and 5 minutes. Feather holding with a hand-held trowel 63 was performed between 2.2 and 2.4N. Five hours and 45 minutes had passed since the injection of water, and the work was carried out for 45 minutes.

The wing hold down of the mounted Trowel 64 was performed 5 times between 2.5 and 2.7N. 6 hours and 31 minutes have passed since the water injection, and the work was done for about 2 hours and 15 minutes. The work was completed when the concrete floor surface 10 reached 3.5 N, at which the solidification of the concrete floor surface 10 ended.

According to the findings of the applicant, it is speculated that the surface pressure applied by the hand-held trowel 61 and the horse-riding trowel 62 falls within the range where vibrations and loads of 3.5 N or more should not be applied. Therefore, when using the riding type trowells 62, 64 or performing finishing work, there is a possibility that cracks may occur.

As a result of this test, the surface pressurization by Trowell 61-64 was performed within the setting time of 0.5 to 2.7 N, and the finish of the concrete floor surface 10 was peeled off from the day after placement to the 10th day. No cracks were found. Therefore, it is considered that a series of work processes for meticulously forming the hardening structure of the concrete floor surface 10 by surface pressure, from surface pressure by the trowels 61 to 64 to finish, is good, and crack suppression and abrasion resistance and impact resistance are considered to be good. It is also considered effective for

10 Concrete floor 30 Laser screed machine 61 First rotary drive machine (hand-held)
62 1st rotary drive machine (riding type)
63 Second rotary drive (hand-held)
64 Second rotary drive machine (riding type)
70 bleeding measuring device

Claims

In the construction method of the concrete floor,
A first step of placing concrete on the floor surface of the construction site;
a second step of leveling the concrete floor with a laser screed machine;
Further comprising a third step of checking the level of the concrete floor leveled by the laser screed machine, and a fourth step of performing vibration compaction again after a predetermined time has elapsed after checking the level of the concrete floor, The re-vibration compaction is performed at the time of bleeding when water grooves begin to form,
A method of constructing a concrete floor, wherein the concrete floor is constructed when the depth of accumulated water reaches 40 to 60% of the depth of the holes formed in the concrete floor.
2. The laser screed machine of claim 1, wherein the laser screed machine has a vibrating blade and a mortar plate located in front of the vibrating blade, the length dimension of the mortar plate being greater than the length dimension of the vibrating blade. Concrete floor construction method.
further comprising a fifth step of surfacing the concrete floor with a rotary disk of a first rotary driver;
The rotary disc includes a pair of discs, the unevenness adjusting means is positioned behind the pair of discs, and the length dimension of the unevenness adjusting means is greater than the length dimension of the pair of discs, 3. The method of constructing a concrete floor according to claim 1, wherein said unevenness adjusting means is brush-shaped.
further comprising a sixth step of finishing the concrete floor with a vane-type rotary trowel of a second rotary drive;
4. The method of constructing a concrete floor according to claim 3, wherein the surface finishing in the fifth and sixth steps is performed with a measured value of 0.5N to 2.7N by a penetration test conforming to JISA1147.
The first and second rotary driving machines have a hand-held type and a riding type, and the surface processing by the riding-type first rotary driving machine is performed when the measured value is between 1N and 2.1N. 5. The method of constructing a concrete floor according to claim 4, wherein the surface finishing by the second rotary driver of the formula is performed while the measured value is between 2.5 and 2.7N.