JP2021095309A - Concrete material, mixing device, manufacturing method and placing method - Google Patents

Abstract

To provide concrete materials, equipment, and methods that make it possible to fill every corner of a formwork while preventing leakage from the formwork.SOLUTION: A concrete material of the invention includes cement, aggregate, water, a water reducing agent, a hardening accelerator which promotes hardening of the concrete, and a plasticizer comprising a polymer emulsion which thickens under an alkaline atmosphere and loses fluidity of the concrete. The concrete material is manufactured using a mixing device 20, and the mixing device 20 includes: a mixing tube 21 comprising, a passage having an inlet and an outlet through which a first material containing cement and aggregate flows, a first inlet for injecting a hardening accelerator and a setting modifier together or separately as a second material, and a second inlet for injecting a plasticizer; and a stirring means disposed in the passage on the outlet side from the second inlet for stirring and mixing the first material, the second material, and the plasticizer injected from the second inlet.SELECTED DRAWING: Figure 4

Description

The present invention relates to a concrete material, a mixing device for obtaining the concrete material, a method for manufacturing the concrete material, and a method for placing the concrete material.

In mountain tunnel construction, concrete is placed on the excavated surface to cover it so that the exposed surface does not loosen and collapse. Conventionally, when placing concrete, concrete to which a quick-setting agent (powder, liquid, or a combination thereof) has been added is used so that the concrete adhering to the excavated surface reaches condensation and hardens in a short time. A sprayer is used to spray concrete with high-pressure compressed air.

In the spraying work, not a little dust is generated during construction, and the amount of concrete rebound during spraying is also large. Therefore, the loss rate of concrete becomes high, and the cost increases. Further, in the spraying work, since many voids are present in the concrete that has been sprayed and hardened, the quality such as the strength and filling property of the concrete may vary. Furthermore, since the concrete is blown off with compressed air in the spraying work, the concrete surface may be uneven and the sprayed thickness may be inhomogeneous. Therefore, after the spraying work, the concrete surface is treated exclusively. It may be necessary to scrape with a tool to adjust the finish as designed.

Therefore, a method of driving a dedicated concrete material into the formwork using a formwork has been proposed (see, for example, Patent Documents 1 and 2). These methods include (1) a method of mixing a material (quick binder or its slurry) that imparts instantaneous binding property to concrete, a setting retarder, and concrete and blowing it into the formwork, or (2). This is a method in which a material that imparts rapid hardness to concrete (a rapid-hardening material or its slurry, a coagulation adjuster, etc.) and concrete are separately pumped and mixed, and then poured into a formwork for construction.

Japanese Unexamined Patent Publication No. 2002-316489 JP-A-2007-217212

In the conventional methods described in (1) and (2) above, when the amount of the setting retarder or the setting adjusting agent used is small, the concrete hardens in a relatively short time, so that leakage from the gap of the formwork is prevented. However, the initial fluidity is not sufficient to fill every corner of the mold, resulting in poor finish. On the other hand, when the amount of the setting retarder or the setting adjusting agent is large, it leaks from the gap of the formwork before the concrete hardens, or the setting start time is slow, so it takes a considerable amount of time to remove the formwork. Needs.

In addition, clarify the device and its mechanism (method) for adding a quick-setting admixture or a slurry of hard-hardening material to the concrete (base concrete), which is the base with large slump and high fluidity, and mixing them uniformly. It is not.

Therefore, it is desired to provide a concrete material that can fill every corner of the formwork while preventing leakage from the formwork, a mixing device for materials (base concrete and agent), a method for manufacturing the concrete material, and the like. It is rare.

To the base concrete containing cement, aggregate, water and water reducing agent, a slurry containing a hardening accelerator and a condensation modifier, or a slurry containing a hardening accelerator and a slurry containing a condensation modifier are separately added and mixed. Furthermore, when a plasticizer that controls the fluidity of concrete is added and mixed, the fluidity is maintained until the concrete is stationary, and it is possible to fill every corner of the formwork, and when it is stationary, the fluidity is lost. , It was found that since the shape is maintained, leakage from the mold can be prevented.

The present invention has been made by finding the above, and the above problems can be solved by providing the concrete material of the present invention, a concrete material manufacturing apparatus, a manufacturing method, and a casting method.

That is, the concrete material is cement, aggregate, water, water reducing agent, hardening accelerator that promotes hardening of concrete, setting adjusting agent that adjusts coagulation, and thickening in an alkaline atmosphere to make concrete. A concrete material is provided that includes a plasticizer consisting of a polymer emulsion that causes loss of fluidity.

Also, a passage having an inlet and an outlet for the first material including cement and aggregate, and a hardening accelerator for promoting the hardening of concrete and a setting modifier for adjusting the setting are used together or separately. A plasticizer composed of a first injection port for injection as a second material and a polymer emulsion that thickens in an alkaline atmosphere and loses the fluidity of concrete is injected on the outlet side from the first injection port. A mixing tube with a second inlet for
It is installed on the outlet side of the second injection port in the passage, and includes a stirring means for stirring and mixing the first material, the second material, and the plasticizer injected from the second injection port.
A mixing device is provided that allows the concrete material produced by stirring and mixing to flow out from the outlet.

According to the present invention, it is possible to fill every corner of the mold while preventing leakage from the mold.

The figure which showed the compounding example of a concrete material and the compressive strength test result. The figure which showed the concrete material being placed in the formwork. The figure which showed the demolded concrete and the state which the concrete was cracked. The figure which showed the 1st configuration example of the mixing apparatus for manufacturing a concrete material. A flowchart showing a flow of manufacturing a concrete material using a mixing device. The figure which showed the 2nd configuration example of a mixing apparatus. The figure which showed the 3rd configuration example of a mixing apparatus. A flowchart showing the flow of placing concrete material using a mixing device. The figure which illustrated the state of placing concrete in a formwork using a mixing device. The figure which showed an example of the cleaning mechanism which cleans the inside of a mixing apparatus.

The concrete material of the present invention includes cement, aggregate, water, a water reducing agent, a hardening accelerator that promotes hardening of concrete, a setting adjusting agent that adjusts coagulation, and a plasticizer that controls the fluidity of concrete. And include. Cement includes Portland cement, mixed cement, and special cement, and any cement can be used. Portland cement is a gray powder composed of clinker and gypsum, and clinker is a mass formed by firing limestone, clay, or the like in a firing kiln such as a rotary kiln.

The mixed cement is a cement composed of Portland cement and a mixed material such as blast furnace slag and fly ash, and the special cement is an alumina cement composed of bokisite and limestone.

The aggregate is sand, gravel, etc., and is divided into fine aggregate and coarse aggregate according to their size. The fine aggregate is an aggregate that all passes through a sieve having a mesh size (mesh size) of 10 mm and 85% or more passes through a sieve having a mesh size of 5 mm, and the above-mentioned sand corresponds to the fine aggregate. The coarse aggregate is an aggregate that cannot pass through a sieve having a mesh size of 5 mm by 85% or more, and the above-mentioned gravel corresponds to it.

Base concrete is produced by putting cement and aggregate into a mixer, adding water and kneading. The base concrete may contain an admixture such as a water reducing agent. The admixture is an additive that is used in a small amount and is not included in the kneaded volume, and is added to improve the quality, performance, economy, etc. of concrete.

Examples of the admixture include an air entraining agent (AE agent), a water reducing agent, an AE water reducing agent, a high-performance water reducing agent, a high-performance AE water reducing agent, and the like. The AE agent is an admixture that reduces air bubbles in concrete and makes it difficult for concrete to crack. A water reducing agent is an admixture that reduces the unit amount of water. The AE water reducing agent is an admixture having both actions of an AE agent and a water reducing agent. A high-performance water reducing agent is an admixture having a higher water reducing rate than a water reducing agent. The high-performance AE water-reducing agent is an admixture having a high water-reducing rate and a small slump loss, similar to the high-performance water-reducing agent. Slump is an indicator of the softness and fluidity of concrete.

The composition of the base concrete is adjusted so that the slump is in the range of 15-23 cm. The standard temperature at which concrete is kneaded is 20 ° C, and is controlled so that it does not fall below 10 ° C.

The hardening accelerator is an admixture material that exerts rapid hardening properties on concrete at an early stage, and examples thereof include chlorides, nitrites, nitrates, sulfates, carbonates, sodium silicates, amines, and maleic anhydride. The coagulation adjuster is an admixture for adjusting the coagulation time, and a polymer or the like to which a modification (hydrophobic group modification) is added so as to be suitable for an adhesive or a binder is used.

The hardening accelerator is dispersed in water or the like, supplied as a slurry, and added to the base concrete. The hardening accelerator and the setting modifier are added immediately before casting because they are materials for adjusting the hardening of concrete.

The standard amount of the hardening accelerator is 20% of the amount of cement in the base concrete, and the amount added is adjusted according to the construction conditions. Hereinafter,% means% by weight unless otherwise specified. The construction conditions are, for example, the construction time, the construction method, the place, the thickness of the concrete, and the like.

The standard amount of the setting modifier is 1.3 to 2.0% with respect to the amount of the hardening accelerator of the base concrete, and the amount added is adjusted according to the construction conditions. When the admixture material (curing accelerator and coagulation adjuster) is added to water to prepare a slurry, the standard water admixture material ratio (water / admixture material) can be 0.5 (50%).

The plasticizer is one of the admixtures, and is added after injecting the slurry into concrete, and retains fluidity until it comes to rest, and when it comes to rest, it loses fluidity and acts to maintain its shape.

Examples of the plasticizer include polymer emulsions (alkali thickening polymer emulsions) that thicken in an alkaline atmosphere and lose the fluidity of concrete. The material is not limited to the alkaline thickening polymer emulsion as long as the material can control the fluidity.

The alkaline thickening polymer emulsion is obtained by copolymerizing an unsaturated carboxylic acid such as acrylic acid or methacrylic acid or an unsaturated carboxylic acid salt thereof with an ethylenically unsaturated compound such as an acrylic acid ester monomer or a methacrylic acid ester monomer. be able to.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like. Examples of the ethylenically unsaturated compound include ethylene, acrylonitrile, methyl acrylate, methyl methacrylate, vinyl acetate, styrene, acrylamide, and methacrylamide.

The blending ratio of the unsaturated carboxylic acid or unsaturated carboxylic acid salt to the ethylenically unsaturated compound is not particularly limited, and is, for example, 95: 5 to 5:95 in terms of molar ratio. Further, the polymerization method of the unsaturated carboxylic acid or unsaturated carboxylic acid salt and the ethylenically unsaturated compound can be any method known so far, for example, emulsion polymerization, suspension polymerization, solution polymerization, etc. A method such as bulk polymerization can be used. When the unsaturated carboxylic acid or unsaturated carboxylic acid salt is polymerized with the ethylenically unsaturated compound, a known polymerization initiator, a polymerization solvent such as a redox catalyst, a chain transfer agent, a surfactant, or the like can be used. ..

The component concentration of the emulsion obtained by the copolymerization is not particularly limited, but is preferably 0.1 to 50%, more preferably 1 to 40%. This is because if the component concentration is less than 0.1%, the thickening effect may be small, and if it exceeds 50%, the emulsion production becomes technically difficult and the stability is impaired. When the amount of cement used is 100 parts, the amount of emulsion used is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts in terms of components with respect to 100 parts of cement. If it is less than 0.01 parts, the thickening effect is not recognized, and for example, it may leak from the mold. On the other hand, if it exceeds 10 parts, the thickening effect is too strong and the filling property into the mold is impaired.

Since the effect of the plasticizer is temperature-dependent, it is desirable to determine the amount of the plasticizer added by conducting a construction test in advance. The construction test can be carried out, for example, in the range of 0.1 to 0.4% with respect to the amount of cement in the base concrete as the amount of the plasticizer added.

FIG. 1 shows a compounding example of concrete and the result of performing a compressive strength test as a construction test. FIG. 1 (a) is a table showing a compounding example of concrete, and FIG. 1 (b) is a table showing the results of a compressive strength test. In FIG. 1 (a), W is water, C is cement, S is fine aggregate, G is coarse aggregate, and s / a is fine aggregate ratio. s / a is the volume ratio of the fine aggregate to the total aggregate. The high-performance water reducing agent is set to 1.0 to 1.2% with respect to the amount of cement C in the base concrete. The fine aggregate S used had a surface dry density of 2.61 g / cm ³ , and the coarse aggregate G used had a surface dry density of 2.68 g / cm ³ . The surface dry density is obtained by dividing the mass of the aggregate in a state where there is no water on the surface and all the internal voids are filled with water (surface dry saturated water state) by the volume of the aggregate containing the internal voids. Is the value to be.

The compressive strength test was carried out by applying a load to a cylindrical specimen having a diameter of 100 mm and a height of 200 mm at a uniform speed with a strength tester and continuing until the specimen was destroyed. The base concrete is a mixture of cement, aggregate, water, and a high-performance water reducing agent in the composition shown in FIGS. 1 (a) and 1 (b), and has a slump of 21 cm and air as shown in FIG. 1 (b). The amount was 4.4% by volume and the concrete temperature was 15.0 ° C. A hardening accelerator, a coagulation adjuster, and a plasticizer were added to the base concrete with the composition shown in FIG. 1 (b), and the mixture was stirred and mixed to obtain a concrete material. The concrete material was packed in a mold, which is a mold for a specimen, placed in the air in a sealed state, demolded with a predetermined material, and tested.

The result of the compressive strength test is the compressive strength of 7 days and 28 days, which indicates the curing period after the concrete material is cast. From the results shown in FIG. 1 (b), it was found that ^{the compressive strength of concrete satisfies the standard of high strength compounding (design standard strength 36 N / mm 2).}

FIG. 2 is a diagram showing a state in which a concrete material is placed in a mold. The formwork 10 has a face plate 11 that is arranged at a certain distance from the surface of the object on which concrete is placed. When the formwork 10 is used for lining the tunnel excavation surface, the formwork 10 is arranged so as to support the tunnel excavation surface and straddle the adjacent flange surfaces of the arch-shaped support works installed at regular intervals in the tunnel direction. The tunnel. For the support work, for example, H-shaped steel having an H-shaped cross section is used. The portion of the two substantially parallel H-shapes is the flange, which has surfaces facing outward from each other, and the surface is the flange surface. Here, the inside of the formwork 10 means an internal area surrounded by a tunnel excavation surface, two support works adjacent to the tunnel excavation surface and arranged at regular intervals, and a face plate 11.

In the example shown in FIG. 2, two adjacent support works are set as two side plates 12 and 13, and a bottom plate 14 is provided. In order to make it easier to check the inside, the tunnel excavation surface is made a transparent acrylic plate, and the face plate 11 and the acrylic plate are used. The inner region surrounded by the two side plates 12, 13 and the bottom plate 14 is set as the inside of the formwork 10, and the concrete material is cast in the formwork 10.

The concrete material is poured into the formwork 10 from above the face plate 11. The face plate 11 may be provided with a driving hole, a notch, or the like at a position close to the upper end of the face plate 11 in the vertical direction. In the example shown in FIG. 2, the concrete material is poured from above the face plate 11 and is filled in every corner on the bottom plate 14. For this reason, large gaps or voids of several centimeters or more cannot be confirmed in the bottom plate 14 and the corners 15 of the two side plates 12 and 13, the boundary 16 between the side plates 12 and 13 and the concrete, and the concrete. It was. From this, it was found that this concrete material improves the filling property of concrete.

Moreover, the finished surface of the concrete was almost smooth. From this, it was found that the use of this concrete material makes it less likely to be influenced by the skill and experience of the operator.

FIG. 3 is a view showing a concrete removed from the formwork 10 and a state in which the concrete is broken. FIG. 3A shows a state in which the concrete was dropped onto the ground after demolding, and FIG. 3B shows a state in which a force was applied to the concrete 17 after demolding and the concrete 17 was split into two. It is a figure. As shown in FIG. 3A, the demolded concrete 17 was a substantially rectangular parallelepiped, had almost no holes or cracks on its surface, and did not crack even when dropped on the ground. Further, as shown in FIG. 3B, it was confirmed that the demolded concrete 17 had almost no hollow portion in the cross section 18 and was densely filled with the concrete material. From this, it was found that the quality and durability of the concrete itself were improved.

Concrete materials include cement, aggregates, water, water reducing agents, hardening accelerators, coagulation regulators, and plasticizers, which can be obtained by mixing these materials using a mixing device. .. FIG. 4 is a diagram showing a first configuration example of the mixing device. The mixing device 20 is connected to a mixing pipe 21 having a hollow inside, a rod-shaped member 22 extending inside the mixing pipe 21, and an end which is one end of the rod-shaped member 22, and rotates the rod-shaped member 22 in a certain direction. The means 23 and a stirring blade 24 provided at a position (tip portion) close to the tip, which is the other end of the rod-shaped member 22, and agitating and mixing the material flowing into the mixing pipe 21 are included.

The mixing pipe 21 is composed of a Y-shaped pipe 21a and a connecting pipe 21b connected to the Y-shaped pipe 21a. The Y-shaped pipe 21a has a straight pipe portion and an oblique pipe portion extending in an oblique direction with respect to the straight pipe portion. The angle between the straight pipe and the diagonal pipe may be any angle, but the base concrete slides down the diagonal pipe and enters the straight pipe toward one end of the straight pipe (exit of the concrete material). It is preferable that the temperature is 30 ° to 60 ° so that the water flows appropriately.

The inner diameters of the Y-shaped pipe 21a and the connecting pipe 21b constituting the mixing pipe 21 can be the same inner diameter, and can be determined according to the supply amount of the base concrete. The inner diameter of the mixing pipe 21 is adjusted in the range of 75 to 150 mm, for example, 100 mm as a standard.

The rotating means 23 is, for example, a motor, and is attached to the other end of the Y-shaped pipe 21a on the side opposite to one end of the straight pipe portion. The rotation speed of the motor is, for example, 100 to 500 rpm.

The rod-shaped member 22 is arranged so as to extend from the other end of the straight pipe portion of the Y-shaped pipe 21a toward one end. The standard diameter of the rod-shaped member 22 is 10 to 20 mm, and the rod-shaped member 22 can be replaced by replacing it.

The stirring blade 24 is a rod provided at the tip of the rod-shaped member 22 and inserted into a hole penetrating from one side surface of the rod-shaped member 22 to the other side surface on the back side thereof, and the number of the rods is one or more. When two or more are arranged, the arrangement interval of the rod-shaped member 22 in the longitudinal direction is 20 to 150 mm. The stirring blade 24 is not limited to a rod, and may be a plate-shaped one or the like. Further, the method of attaching the stirring blade 24 is not limited to the method of inserting into the hole, and a method of welding to the rod-shaped member 22 or the like may be adopted.

The base concrete is supplied into the connecting pipe 21b, and is supplied into the straight pipe portion through the diagonal pipe portion of the Y-shaped pipe 21a to which the connecting pipe 21b is connected. Then, the base concrete is stirred by the rotation of the stirring blade 24 while moving toward one end of the straight pipe portion. The straight pipe portion is connected to the face plate 11 so that the opening at one end of the straight pipe portion is continuous with the driving hole or the like provided in the face plate 11 of the formwork 10.

The Y-shaped tube 21a is provided with an injection port 25 for adding a plasticizer to the side surface of the straight tube portion. The injection port 25 is a protruding nozzle or the like, and a pipe such as a hose for supplying a plasticizer is connected to the injection port 25. A check valve is arranged in the hole of the injection port 25 to allow the concrete paste to enter (backflow). To prevent. The connecting pipe 21b has an inlet 26 into which the base concrete flows, and has an injection port 27 on the side surface for injecting a slurry containing a hardener. A pipe for supplying base concrete is connected to the inlet 26, and a pipe for supplying slurry is connected to the inlet 27. These connections may use flanges, bolts and nuts, or may use fittings.

The base concrete enters the Y-shaped pipe 21a after the slurry is injected in the connecting pipe 21b. The base concrete and the slurry enter the straight pipe portion through the diagonal pipe portion of the Y-shaped pipe 21a, a plasticizer is added to the straight pipe portion, and the slurry moves toward one end of the straight pipe portion.

When the base concrete, the slurry, and the plasticizer approach one end of the straight pipe portion, they are agitated and mixed by the stirring blade 24 arranged at a position close to one end of the straight pipe portion. The concrete material obtained by stirring and mixing is immediately discharged from one end of the straight pipe portion, and is cast into the mold 10 through a casting hole or the like of the face plate 11 provided in the mold 10. In this way, since the concrete material is cast immediately after mixing, each material is continuously supplied into the mixing device 20, and the concrete material does not harden in the mixing pipe 21 while stirring and mixing.

When the concrete material to be cast in the formwork 10 passes through the casting hole or the like, it falls downward and is piled up at the dropped point. It is difficult to adjust the delicate time until the curing starts with the curing accelerator alone. Therefore, if the curing is fast, it hardens before spreading in the mold 10, and it is not possible to fill every corner in the mold 10. On the other hand, if the curing is slow, the concrete material leaks from the gap between the formwork 10 and the support work, and the formwork 10 cannot be filled. Therefore, it is necessary to use a coagulation adjuster together.

When a plasticizer is added, the base concrete instantly thickens due to the effect of the plasticizer. On the other hand, the base concrete has fluidity due to the energy applied by pumping.

When the concrete material is poured into the formwork 10, it flows in the formwork 10 so as to spread without receiving so much resistance. On the other hand, when the formwork 10 or the support work is reached, although there is a gap between the formwork 10 and the support work, the width is narrow, so that the formwork stays there and becomes stationary. Then, the concrete material loses its fluidity due to the plasticizer and maintains its shape. Since the concrete material contains a hardening agent, it condenses in its shape and hardens.

The Y-shaped pipe 21a is provided with, for example, a flange at the other end of the straight pipe portion, and the rotating means 23 is also provided with a flange, and can be connected using bolts and nuts. With such a configuration, the rotating means 23 to which the rod-shaped member 22 is connected can be easily removed from the mixing pipe 21, and after the removal, water is sprayed into the mixing pipe 21 to push out the residue. , The inside can be cleaned.

The injection port 25 is not limited to the straight pipe portion, but may be provided in the diagonal pipe portion or the connecting pipe 21b. However, the injection port 25 is not between the inlet 26 of the connecting pipe 21b and the injection port 27, but is located on the diagonal pipe portion side of the injection port 27. If it is provided on the inlet 26 side and the plasticizer is added first, the base concrete is instantly thickened, so that the slurry injected later is difficult to mix and the distance to the stirring blade 24 becomes long. This is because the viscosity becomes high, stirring by the stirring blade 24 becomes difficult, and the stirring blade 24 may be damaged.

A method of mixing the base concrete, the slurry, and the plasticizer will be described with reference to FIG. Starting from step 100, in step 101, the rod-shaped member 22 is rotated by the rotating means 23, and stirring by the stirring blade 24 is started. Here, the stirring is started first, but the stirring may be started after supplying each material.

In step 102, the base concrete is press-fitted into the connecting pipe 21b from the inlet 26 at a constant flow rate. In step 103, the slurry is injected into the base concrete from the injection port 27 at a constant flow rate. The slurry is injected at a pressure higher than the pressure of the pumped base concrete. The base concrete and the slurry move in the diagonal pipe portion of the Y-shaped pipe 21a by the base concrete that is continuously press-fitted, and enter the straight pipe portion.

In step 104, the plasticizer is added from the injection port 25 at a constant flow rate. The plasticizer is injected at a higher pressure than the pumped base concrete and slurry. The plasticizer moves toward one end of the straight pipe portion together with the base concrete and the slurry. In step 105, when each material reaches the position where the stirring blade 24 is arranged, each material is stirred and mixed by the rotation of the stirring blade 24. As a result, a concrete material for placing is obtained. When the concrete material is discharged from one end of the straight pipe portion, the process proceeds to step 106 to finish mixing the respective materials.

When the mixing of each material is completed, if it is left as it is, the residue such as base concrete hardens inside the mixing pipe 21 and blocks the inside of the mixing pipe 21. When the residue hardens and adheres to the mixing tube 21, it becomes difficult to remove the residue. Therefore, before the residue is cured, the residue is extruded by injecting high-pressure water into the mixing pipe 21 to clean the inside.

The mixing device 20 is not limited to the configuration shown in FIG. 4, and may have a configuration in which a branch pipe 29 provided with a switching valve 28 is attached to the injection port 27 of the connection pipe 21b as shown in FIG. 6, for example. One of the branch pipes 29 can be connected to the inlet 27, one can be connected to the pipe that supplies the slurry, and the other one can be connected to the pipe that supplies water. As a result, the inside of the mixing pipe 21 can be easily cleaned by stopping the supply of the slurry and supplying water after the construction by simply switching the switching valve 28.

Further, the mixing device 20 does not use the Y-shaped pipe 21a as shown in FIGS. 4 and 6, but is a curved pipe 30 produced by welding a short pipe having a constant curvature between two short pipes. May be used, the rod-shaped member 22 may be hollow, and the swivel mechanism 31 may be provided. The curved pipe 30 has a hole through which the rod-shaped member 22 can be rotatably inserted. The rod-shaped member 22 has an opening on the side surface, and the end thereof is connected to the rotating means 23. The mixing device 20 is provided with a swivel mechanism 31 so as to cover the opening provided in the rod-shaped member 22, and the swivel mechanism 31 is provided with an injection port 32 for adding a plasticizer into the rod-shaped member 22.

The swivel mechanism 31 rotatably supports the rod-shaped member 22 inside, and supplies the plasticizer from the pipe connected to the injection port 32 into the hollow rod-shaped member 22 through the opening. For example, the swivel mechanism 31 has a plurality of spheres adjacent to the periphery of the rod-shaped member 22, and the plurality of spheres rotate freely to rotatably support the rod-shaped member 22 inside. It should be noted that such a structure is an example, and the swivel mechanism 31 is not limited to such a structure.

The rod-shaped member 22 is provided with a stirring blade 24 at the tip end portion, and is provided with at least one injection hole 33 communicating with the inside on the terminal side from the mounting position of the stirring blade 24. In the example shown in FIG. 7, the rod-shaped member 22 includes two injection holes 33. The base concrete into which the slurry is injected is pumped into the curved pipe 30, and the plasticizer is injected into the base concrete from the injection hole 33. After that, the base concrete, the slurry, and the plasticizer are stirred and mixed by the stirring blade 24.

Here, a configuration in which the plasticizer is injected from the injection hole 33 of the rod-shaped member 22 has been illustrated, but the present invention is not limited to this, and the injection port 25 is provided with an injection port 25 for adding the plasticizer to the curved pipe 30. An injection hole 33 may be provided on the swivel mechanism 31 or the rotating means 23 side, and the slurry may be injected from the injection hole 33.

A method of placing the produced concrete material using the mixing device 20 will be described with reference to FIGS. 8 and 9. Here, the concrete material will be described as arranging the formwork 10 on the tunnel excavation surface and placing it in the formwork 10. The concrete material can be used for construction other than tunnel construction as long as it is poured into the formwork 10 and placed.

Starting from step 200 shown in FIG. 8, step 201 prepares for pumping the base concrete. Specifically, as shown in FIG. 9, the base concrete is produced in the batcher plant 40 by kneading an admixture such as cement, an aggregate, and a water reducing agent with a mixer 41. The base concrete is transported to the construction site as a ready-mixed concrete by a mixer truck 42. In this preparation, the mixer truck 42 is installed in the vicinity of the pumping pump 43 as the pumping means for pumping concrete, and the pumping pump 43 is connected to the inlet 26 of the mixing device 20 by using a pipe 44 such as a pressure resistant hose. To do.

In step 202, preparation for slurry supply is performed. A curing accelerator and a coagulation adjuster are dispersed in water to prepare a slurry, and the prepared slurry is placed in a container 45 for storing the slurry. Further, the container 45 is connected to the injection port 27 of the mixing device 20 by using a pipe 47 such as a hose via a liquid pump 46 as a supply means. The curing accelerator and the coagulation adjuster may be dispersed in separate waters to prepare two slurries, and each slurry may be stored in separate containers. In this case, each slurry will be injected separately.

In step 203, the plasticizer supply is prepared. The plasticizer is placed in the container 48 for storing the plasticizer, and the container 48 is connected to the injection port 25 of the mixing device 20 by using a pipe 50 such as a hose via a liquid pump 49 as a supply means.

In step 204, as shown in FIG. 9, the mixing device 20 is attached to the formwork 10, and the formwork 10 is installed so as to straddle two adjacent support works and separated from the inner surface 60 of the tunnel.

The formwork 10 may be attached to a concrete sprayer and attached to an erector used when building a support. As a result, after the casting of the concrete material into the formwork 10 is completed, the formwork 10 is moved to the next position, the concrete material is cast in the same manner, and this is repeated to support the two supports. It is possible to move the work surface in the circumferential direction of the tunnel and place concrete material in the entire circumferential direction between the two support works.

The operations of steps 201 to 204 are not limited to this order, and may be performed at the same time.

In step 205, the rotating means 23 is activated to start the rotation of the stirring blade 24. Here, too, the stirring is started before the supply of each material, but the stirring may be started after each material is supplied. In step 206, the base concrete is fed from the mixer truck 42 to the pump 43, and the base concrete is pumped to the mixing device 20 via the pipe 44 by the pump 43. Further, the liquid pumps 46 and 49 are started to supply the slurry and the plasticizer to the mixing device 20 via the pipes 47 and 50.

Pressure pump 43, the amount of work by the conventional spray Engineering with reference, the pumping quantity The standard ^{6 m} 3 / h, is adjusted within a range of 2 to 15 m ³ / h. The liquid pump 46 is adjusted in the range of 2 to 15 liters per minute with a standard of 8 liters per minute at ^{6 m 3 / h of base concrete.} The liquid pump 49 is adjusted in the range of 0.5 to 3 liters per minute with a standard of 1 liter per minute at 6 m3 / h of base concrete.

In step 207, the slurry is injected into the pumped base concrete, and in step 208, a plasticizer is added to the base concrete and the slurry. In step 209, the base concrete, slurry, and plasticizer are stirred and mixed by the stirring blade 24 to obtain a concrete material.

In step 210, the concrete material is poured into the formwork 10 from the mixing device 20 and placed. The concrete material is cast up to a predetermined height position, which is lower than the height position of the casting hole or the like provided in the formwork 10. When the filling has reached a predetermined height position, the process proceeds to step 211 to end the concrete material placing operation.

When the concrete is placed continuously using the erector, the concrete material can be placed by moving the formwork 10 after the concrete reaches condensation and becomes self-supporting. In this case, the inside of the mixing pipe 21 may be washed with water every time the mold 10 is moved, or since it is used continuously, it may be washed with water after moving several times.

When casting is continuously performed using the Elector, the formwork 10 can be slid and moved in the circumferential direction on the two support works.

FIG. 10 is a diagram showing an example of a cleaning mechanism for cleaning the inside of the mixing pipe 21 with water. The cleaning mechanism 70 is arranged between the mixing pipe 21 and the formwork 10 and operates so as to open a casting hole or the like when supplying the concrete material and to close the casting hole or the like when cleaning with water. ..

The cleaning mechanism 70 includes a hollow connecting member 71 that connects the mixing pipe 21 and the formwork 10, a discharge pipe 72 that extends downward from the connecting member 71, a shutter 73, a casting hole, or an opening of the discharge pipe 72. Includes a cylinder 74 that moves the shutter 73 to close.

The discharge pipe 72 is a bellows pipe that can be partially expanded and contracted. The shutter 73 is a plate member having a size capable of closing the driving hole and the like and the opening of the discharge pipe 72, and is provided with a hinge at one end and is configured to be rotatable around one end. The cylinder 74 is connected to a discharge pipe 72 which is connected to one end of the shutter 73 at a constant angle, and by moving the other end of the shutter 73 to the formwork side or the discharge pipe side, a casting hole or the like or The opening of the discharge pipe 72 is closed. At this time, as the shutter 73 rotates around the hinge, the discharge pipe 72 also rotates around the hinge. The cylinder 74 may be expanded and contracted by any of hydraulic pressure, air pressure, water pressure, and electric power.

When placing the concrete material using the formwork 10, as shown in FIG. 10A, the cylinder 74 moves the other end of the shutter 73 downward so as to tilt it downward, and the lower side of the connecting member 71. The opening of the discharge pipe 72 provided in the above is closed. As a result, the concrete material does not flow into the discharge pipe 72, but is cast into the formwork 10 through the casting holes and the like as shown by the arrows.

On the other hand, when water is supplied to the mixing pipe 21 and the inside of the mixing pipe 21 is cleaned, as shown in FIG. 10B, the cylinder 74 moves the other end of the shutter 73 so as to raise it upward, and molds the mold. The casting hole and the like of the frame 10 are closed. As a result, the water supplied into the mixing pipe 21 can be discharged through the discharge pipe 72.

As explained above, by providing a concrete material in which a plasticizer, a hardening accelerator, and a coagulation regulator are used in combination, the concrete filling property in the formwork is improved, and the quality and durability of the concrete itself can be improved. Can be improved. In addition, the hardening of concrete is promoted, the initial strength is well developed, and the mold can be quickly removed from the mold.

Further, by mixing using the mixing device having the above configuration, the base concrete and each admixture can be efficiently stirred and mixed. Since the concrete material obtained by stirring and mixing is cast by pouring it into the mold, it is possible to suppress the generation of dust and the generation of loss due to rebound.

So far, the concrete material, the mixing device, the mixing method, and the method of placing the concrete material of the present invention have been described in detail with the above-described embodiments, but the present invention is not limited to the above-described embodiments, and other The embodiment of the above, addition, modification, deletion, etc. can be changed within the range conceivable by those skilled in the art, and any aspect is included in the scope of the present invention as long as the action / effect of the present invention is exhibited. It is something that can be done.

10 ... Mold 11 ... Face plate 12, 13 ... Side plate 14 ... Bottom plate 15 ... Corner 16 ... Boundary 17 ... Concrete 18 ... Cross section 20 ... Mixing device 21 ... Mixing pipe 21a ... Y-shaped pipe 21b ... Connecting pipe 22 ... Rod-shaped member 23 ... Rotating means 24 ... Stirring blade 25 ... Injection port 26 ... Inlet 27 ... Injection port 28 ... Switching valve 29 ... Branch pipe 30 ... Curved pipe 31 ... Swivel mechanism 32 ... Injection port 33 ... Hole 40 ... Batcher plant 41 ... Mixer 42 ... Mixer car 43 ... Pressure pump 44, 47, 50 ... Pipe 45, 48 ... Container 46, 49 ... Liquid pump 60 ... Tunnel inner surface 70 ... Cleaning mechanism 71 ... Connecting member 72 ... Discharge pipe 73 ... Shutter 74 ... Cylinder

Claims (5)

Cement, aggregate, water, water reducing agent, hardening accelerator that accelerates the hardening of concrete, setting modifier that adjusts coagulation, and polymer that thickens in an alkaline atmosphere and loses the fluidity of concrete. A concrete material containing a plasticizer consisting of an emulsion. A passage having an inlet and an outlet for the first material including cement and aggregate, and a hardening accelerator for promoting the hardening of concrete and a setting modifier for adjusting the setting are used together or separately. To inject a plasticizer composed of a first injection port for injecting as a material of the concrete and a polymer emulsion that thickens in an alkaline atmosphere and loses the fluidity of concrete on the outlet side from the first injection port. A mixing tube with a second inlet and
With a stirring means installed on the outlet side of the second injection port in the passage and stirring and mixing the first material, the second material, and the plasticizer injected from the second injection port. Including
A mixing device that allows a concrete material produced by stirring and mixing to flow out from the outlet. A passage having an inlet and an outlet for the first material including cement and aggregate, and a hardening accelerator for promoting the hardening of concrete and a coagulation modifier for adjusting the coagulation are used together or separately. A mixing tube with a third inlet for injecting as a material of
An injection pipe provided with a fourth injection port for injecting a plasticizer made of a polymer emulsion that thickens in an alkaline atmosphere and loses the fluidity of concrete on the outlet side of the third injection port.
The plastic that is integrally connected to the injection pipe, is installed on the outlet side of the fourth injection port in the passage, and is injected from the first material, the second material, and the fourth injection port. Including a stirring means for stirring and mixing the agent.
A mixing device that allows a concrete material produced by stirring and mixing to flow out from the outlet. The first material containing cement, aggregate, water and water reducing agent is infused with a hardening accelerator that accelerates the hardening of concrete and a coagulation adjuster that adjusts coagulation as a second material together or separately. Stages and
A step of injecting a plasticizer composed of a polymer emulsion that thickens in an alkaline atmosphere and loses the fluidity of concrete into the first material into which the second material has been injected.
A method for producing a concrete material, which comprises a step of mixing the first material, the second material, and the plasticizer. It is a method of placing concrete material,
The stage of installing the formwork and
The first material containing cement, aggregate, water and water reducing agent is infused with a hardening accelerator that accelerates the hardening of concrete and a coagulation adjuster that adjusts coagulation as a second material together or separately. Stages and
A step of injecting a plasticizer composed of a polymer emulsion that thickens in an alkaline atmosphere and loses the fluidity of concrete into the first material into which the second material has been injected.
The step of mixing the first material, the second material, and the plasticizer,
A casting method including a step of casting a concrete material obtained by mixing into the formwork.

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