JP6969046B2 - Method of manufacturing a mixture using residual ready-mixed concrete - Google Patents

Description

The present invention relates to a method for producing a mixture using residual ready-mixed concrete, and more specifically, the ready-mixed concrete remaining at a construction site or the like can be easily reformed into a new mixture using an agitator vehicle, and the agitator vehicle can be used. It relates to a method for producing a mixture using residual ready-mixed concrete capable of cleaning the inside of a drum.

As a means of transporting ready-mixed concrete (hereinafter referred to as ready-mixed concrete) made at a manufacturing plant to a construction site, an agitator vehicle (truck mixer, ready-mixed concrete vehicle) equipped with a rotatable drum on the loading platform is used. At construction sites, if there is a shortage of ready-mixed concrete during construction, work will be delayed, so it is common to bring in slightly more ready-mixed concrete than is actually used. Therefore, some ready-mixed concrete remains at construction sites and the like.

The remaining ready-mixed concrete is returned to the ready-mixed concrete factory and separated into sludge water, fine aggregate and coarse aggregate by a washing treatment. This cleaning process requires a lot of labor and cost. There is also a method of discharging the remaining ready-mixed concrete to the outside of the agitator car, solidifying it, and then crushing it into crushed stones for disposal, but the crushing work requires a lot of time and labor.

On the other hand, for an agitator car, water is poured into the inside of the drum using a hose, and the drum with the water is rotated to clean the inside of the drum to which the ready-mixed concrete is attached. In addition, workers regularly enter the inside of the drum and manually remove the concrete lumps that have adhered to the inner wall of the drum and the mixing blade and have hardened, using a spatula or the like. As a method for effectively cleaning the inside of the drum, a method of injecting water at a high pressure to clean the inside of the drum has been proposed, but in this case, a large-scale device is required (see, for example, Patent Document 1). ). Further, in this method, a large amount of sewage is generated after cleaning the inside of the drum, so that the treatment of sewage is also a problem.

By the way, a fluidity reducing agent used for improving excavated soil obtained at a construction site has been proposed (see Patent Documents 2 and 3). This fluidity reducing agent contains granules having a structure in which fibers are entangled, and when mixed with excavated soil, water and soil particles in the soil are physically restrained in the voids formed by the entanglement of fibers. Due to this property, the excavated soil can be improved into a reinforcing soil having sufficient strength for practical use. The inventors of the present application paid attention to the characteristics of this fluidity reducing agent, and as a result of various studies, came to create the invention of the present application.

Japanese Unexamined Patent Publication No. 2004-195446 Japanese Patent No. 5913267 Japanese Patent No. 5959709

An object of the present invention is to use the residual ready-mixed concrete that can be easily reformed into a new mixture by using an agitator vehicle and can clean the inside of the drum of the agitator vehicle. The purpose is to provide a method for producing the mixture.

In order to achieve the above object, the method for producing a mixture using the residual ready-mixed concrete of the present invention is an agitator containing the residual ready-mixed concrete and a fluidity reducing agent which is a granular material having voids in a structure in which fibers are entangled. By rotating the drum of the car, the ready-mixed concrete and the fluidity reducing agent were stirred and mixed to form a lump, and the lump was discharged from the opening of the drum, and the ready-mixed concrete was used. In producing the lumpy body which is a mixture, the amount of the fluidity reducing agent to be added by stirring and mixing with the ready-mixed concrete is the weight of the water content in the ready-mixed concrete and the weight of the fluidity reducing agent. It is set based on the ratio, and is characterized in that the granules in a state where air is held in the voids and the ready-mixed concrete are stirred and mixed.

According to the present invention, it is possible to produce a lumpy body in which the two are completely integrated by simply rotating the drum of the agitator wheel containing the residual ready-mixed concrete and the fluidity reducing agent and stirring and mixing the two. The lumpy body obtained by modifying the ready-mixed concrete in this way can be effectively used as a landfill material or the like. Moreover, it has the advantage of treating ready-mixed concrete remaining at construction sites and the like. Furthermore, in the process of producing the lumpy body, the fluidity reducing agent and the ready-mixed concrete adhering to the inner wall of the drum and the mixing blade are mixed inside the rotating drum, and gradually grow as a lumpy body. Since the ready-mixed concrete is taken in as a constituent member of the lump body, it is removed from the inner wall of the drum and the mixing blade to clean the inside of the drum. Along with this, the time and labor required for cleaning the agitator vehicle can be significantly reduced. Since the lumps are manufactured using the water contained in the ready-mixed concrete, there is no need to use additional water, or even when water is added, the amount of water used is extremely small, and sewage. Rarely occurs.

When the main component of the fiber constituting the fluidity reducing agent is a hydrophilic polymer such as cellulose, since it has a large number of hydrophilic groups, it is contained in the ready-mixed concrete that has penetrated into the communication voids formed by the fiber. An electrical attraction acts between the existing moisture and the fibers. Therefore, the water that has entered the communicative void is restrained, so that the fluidity of the ready-mixed concrete is reduced and it becomes easy to produce a lumpy body.

Further, when the weight of the fluidity reducing agent to be stirred and mixed with the ready-mixed concrete is, for example, 5% or more and 17% or less of the weight of the water contained in the ready-mixed concrete, it becomes easier to produce a lumpy body.

It is also possible to put the fluidity reducing agent into the inside of the drum in a state of being put in a bag made of alkaline-dissolved paper. The granular fluidity reducing agent is easy to scatter, but the liquidity reducing agent can be prevented from scattering by putting it in a bag. Since the bag made of alkaline-dissolved paper is dissolved by alkaline ready-mixed concrete, the bag does not remain even if the fluidity reducing agent is put in the bag as it is.

It is explanatory drawing which illustrates the situation which puts the fluidity reducing agent into the drum of the agitator car in the state which contained the ready-mixed concrete from the side view through the inside of the drum. It is explanatory drawing which illustrates the situation in which the drum containing the ready-mixed concrete and the fluidity reducing agent is rotated and agitated and mixed is performed by seeing through the inside of the drum and exemplifying it from the side view. It is explanatory drawing which illustrates the state in which the manufactured mass is discharged to the outside of a drum by seeing through the inside of a drum, and exemplifying from the side view.

Hereinafter, a method for producing a mixture using the residual ready-mixed concrete of the present invention will be described based on the embodiment shown in the figure. In FIGS. 1 to 3, the inside of the drum of the agitator vehicle is visualized and shown by a broken line.

As shown in FIG. 1, after the ready-mixed concrete 1 (hereinafter referred to as the ready-mixed concrete 1) is brought into the construction site or the like by the agitator vehicle 10, some ready-mixed concrete 1 remains. In the present invention, the residual ready-mixed concrete 1 and the fluidity reducing agent 2 conventionally used for improving excavated soil and the like are skillfully used to produce a mass that can be used as a landfill material, an embankment material, or the like.

The agitator vehicle 10 is provided with a rotatable tubular drum 11 for accommodating the ready-mixed concrete 1 in the loading platform portion. The drum 11 is arranged so that the drum cylinder axis direction faces the vehicle body front-rear direction of the agitator vehicle 10, and the drum 11 is installed on the vehicle body in an inclined state with the rear side of the main body higher than the front side. An opening 12 is provided on the upper side of the drum 11 (upper left side of the drum 11 in FIGS. 1 to 3), and a spiral mixing blade 13 (hereinafter referred to as a spiral mixing blade 13) is provided inside the drum 11 along the inner wall surface of the drum 11. , The blade 13) is arranged.

When the drum 11 is rotated in one direction, the ready-mixed concrete 1 housed inside the drum 11 is pushed toward the lower side of the drum 11 (lower right side of the drum 11 in the figure) and stirred by the blade 13, and the drum 11 is moved to the other. When rotated in the direction, the ready-mixed concrete 1 is sent out to the upper side of the drum 11 by the blade 13, and the ready-mixed concrete 1 is discharged from the opening 12. On the upper side of the opening 12, a charging portion 14 (hopper) is provided inside the drum 11 to communicate with the ready-mixed concrete 1 and the opening portion 12 for charging the material of the ready-mixed concrete 1. A discharge portion 15 (scoop, chute) communicating with the opening 12 for guiding the ready-mixed concrete 1 discharged from the opening 12 to the unloading position is provided.

As shown in FIG. 1, in the present invention, first, the fluidity reducing agent 2 is charged into the drum 11 in a state where the ready-mixed concrete 1 remaining in the drum 11 of the agitator vehicle 10 is accommodated, and the ready-mixed concrete 1 is placed inside the drum 11. The fluidity reducing agent 2 and the liquidity reducing agent 2 are housed in the state.

The fluidity reducing agent 2 used in the present invention is a granular material (powdered material) having a structure in which fibers are entangled. This granular material has an average particle size of 300 μm or less, and has a specific surface area of 0.25 m ² / g or more and 100 m ² / g or less by the BET method, or is calculated by (1-bulk density / true density) × 100. The porosity is 50% or more, and the specific surface area by the BET method is 0.25 m ² / g or more and 100 m ² / g or less. The average particle size referred to here is an average value of the particle size measured under an optical microscope.

As the fiber constituting the fluidity reducing agent 2, for example, a fiber containing a hydrophilic polymer is preferable. Examples of the hydrophilic polymer include cellulose, polyvinyl alcohol, polyalkylene glycol (for example, polyethylene glycol, polypropylene glycol, etc.), polyacrylic acid, and the like. As this fiber, cellulose is preferable because it has biodegradability and a pH in the neutral range (for example, around pH 8) and is excellent in low environmental load. The fluidity reducing agent 2 can be obtained, for example, by pulverizing a piece of paper such as shredder waste or used paper with a mill.

The fluidity reducing agent 2 is an inorganic filler such _{as calcium carbonate (CaCO 3} ), kaolin (Al ₄ Si ₄ O ₁₀ (OH) ₈ ), talc (Mg ₃ Si ₄ O ₁₀ (OH) _{2), etc. as optional components.} May include.

In this embodiment, the fluidity reducing agent 2 is put in a bag 3 made of alkaline-dissolved paper and sealed. Then, the fluidity reducing agent 2 is charged into the drum 11 from the charging unit 14 in a state of being contained in the bag 3. The alkaline-dissolved paper is a material that dissolves in an alkaline aqueous solution such as polyvinyl alcohol paper and polyvinyl alcohol-coated paper, and the ready-mixed concrete 1 is alkaline. Therefore, the bag 3 made of the alkaline dissolving paper enters the drum 11 and dissolves when it comes into contact with the ready-mixed concrete 1. That is, even if the fluidity reducing agent 2 is put in the bag 3 as it is, the bag 3 does not remain in the drum 11.

The granular fluidity reducing agent 2 is easily scattered, but by handling the fluidity reducing agent 2 in the bag 3 in this way, it flows when the fluidity reducing agent 2 is transported or put into the drum 11. It is possible to prevent the sex lowering agent 2 from scattering. Further, by using the bag 3 made of alkaline-dissolved paper, the fluidity reducing agent 2 can be charged from the charging unit 14 in the state of being contained in the bag 3, so that the fluidity reducing agent 2 can be charged. It is possible to improve the efficiency of the work of putting into the drum 11.

It is advisable to prepare the fluidity reducing agent 2 in advance by dividing it into bags 3 for each predetermined weight (for example, 5 kg or 10 kg). By subdividing the fluidity reducing agent 2 into the bags 3, it becomes easy to grasp the weight of the fluidity reducing agent 2 to be charged into the drum 11, so that it is not necessary to weigh the fluidity reducing agent 2 at the site. Even when the fluidity reducing agent 2 is added, the amount of the fluidity reducing agent 2 can be easily adjusted.

Next, as shown in FIG. 2, the ready-mixed concrete 1 and the fluidity reducing agent 2 are stirred inside the drum 11 by rotating the drum 11 containing the ready-mixed concrete 1 and the fluidity reducing agent 2 in one direction. Mix.

When the ready-mixed concrete 1 and the fluidity-reducing agent 2 are stirred and mixed, the air in which the water and cement particles constituting the ready-mixed concrete 1 fill the communication voids in the cotton-like structure of the fluidity-reducing agent 2 is tiny air (minimum air). It becomes a bubble) and is physically restrained in the communicative void together with these airs. When the fluidity reducing agent 2 contains a hydrophilic polymer such as cellulose, an electric attractive force acts between the water molecule and the fiber constituting the void due to the large number of hydrophilic groups of the hydrophilic polymer. Water that has entered the communication void is more strongly constrained. Then, the cement particles and aggregates that are the materials of the ready-mixed concrete 1 are put together by the fluidity-reducing agent 2, and the ready-mixed concrete 1 and the fluidity-reducing agent 2 are completely integrated to form a lump body 4.

In the process of producing the agglomerate 4, the fluidity reducing agent 2 and the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 are mixed inside the rotating drum 11 and gradually grow as the agglomerate 4. I will go. The ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 is taken in as a constituent member of the agglomerate 4, and is therefore removed from the inner wall of the drum 11 and the blade 13. In the process of growing the lump body 4, the lump body 4 also collides with the inner wall of the drum 11 and the blade 13, so that the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 is removed.

The mixing ratio of the ready-mixed concrete 1 and the fluidity reducing agent 2 is set to an appropriate ratio by test mixing or the like. When the fluidity reducing agent 2 is cellulose, the weight of the fluidity reducing agent 2 to be stirred and mixed with the ready-mixed concrete 1 is, for example, 5% or more and 17% or less, more preferably 8 of the weight of the water contained in the ready-mixed concrete 1. % Or more and 13% or less. By adjusting the mixing ratio of the ready-mixed concrete 1 and the fluidity reducing agent 2 to this ratio, it becomes easier to produce the agglomerate 4. When the weight of the fluidity reducing agent 2 to be stirred and mixed is smaller than 5% of the weight of the water contained in the ready-mixed concrete 1, the fluidity reducing agent 2 cannot sufficiently absorb the water of the ready-mixed concrete 1 and the ready-mixed concrete is not sufficiently absorbed. 1 becomes difficult to organize in a lump. On the other hand, when the weight of the fluidity reducing agent 2 to be stirred and mixed is larger than 17% of the weight of the water contained in the ready-mixed concrete 1, the fluidity reducing agent 2 may be excessive.

The rotation speed of the drum 11 when the ready-mixed concrete 1 and the fluidity reducing agent 2 are stirred and mixed can be appropriately determined according to the size of the drum 11, the weight of the ready-mixed concrete 1, the amount of water contained in the ready-mixed concrete 1, and the like. It is preferable to rotate 1 at a speed higher than the normal rotation speed when transporting 1. Specifically, for example, the rotation speed of the drum 11 is set to about 20 to 30 rpm (revolutions per minute).

The time for stirring and mixing the ready-mixed concrete 1 and the fluidity reducing agent 2 can be appropriately determined according to the size of the drum 11, the weight of the ready-mixed concrete 1, the amount of water contained in the ready-mixed concrete 1, and the like. Specifically, for example, ^{if the volume of the remaining ready-mixed concrete 1 is about 1 m 3} , the stirring and mixing time is about 2 minutes to 5 minutes. When the stirring and mixing of the ready-mixed concrete 1 and the fluidity reducing agent 2 progresses sufficiently and almost all the ready-mixed concrete 1 becomes a lump body 4, a sound of the lumpy body 4 colliding with the inner wall of the drum 11 or the like is generated. It is also possible to determine when to finish stirring and mixing.

When the fluidity of the remaining ready-mixed concrete 1 is low, a small amount of water can be added to the inside of the drum 11 before the fluidity reducing agent 2 is charged into the drum 11. By adding water and rotating the drum 11, the fluidity of the ready-mixed concrete 1 can be increased, and the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 can be easily removed. In this case, the weight of the fluidity reducing agent 2 to be added may be determined by taking into consideration the amount of water contained in the remaining ready-mixed concrete 1 and the weight of the added water.

Next, as shown in FIG. 3, after almost all the ready-mixed concrete 1 in the drum 11 is formed in the lump body 4, the drum 11 is rotated in the other direction and the lump body 4 is discharged from the opening 12 to the outside of the drum 11. Let me. The particle size of the produced mass 4 is, for example, about several mm to 40 mm. The manufactured lump body 4 can be used, for example, as a landfill material or embankment material for forming a landfill site, a temporary work material in a site, a split chestnut stone under discarded concrete, a roadbed material under pavement, or the like. can. When the lump 4 is discharged from the drum 11, the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 is reformed into the lump 4 and is largely removed.

As described above, according to the present invention, simply by rotating the drum 11 of the agitator wheel 10 containing the residual ready-mixed concrete 1 and the fluidity reducing agent 2 and stirring and mixing the two, the two are completely integrated. 4 can be manufactured. The lump body 4 can be effectively used as a landfill material, an embankment material, or the like. Moreover, there is an advantage that the ready-mixed concrete 1 remaining at the construction site or the like can be easily processed in a short time.

Further, in the process of manufacturing the lump body 4, the fluidity reducing agent 2 and the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 are taken in as the constituent members of the lump body 4 inside the rotating drum 11. The adhering ready-mixed concrete 1 is removed from the inner wall of the drum 11 and the blade 13 to clean the inside of the drum 11. Further, when the mass 4 collides with the inner wall of the drum 11 and the blade 13, the ready-mixed concrete 1 adhering to the inner wall of the drum 11 and the blade 13 is effectively removed. Along with this, the time and labor required for cleaning the agitator vehicle 10 can be significantly reduced. The amount of water used for cleaning the drum 11 can also be significantly reduced as compared with the conventional case, and the sewage generated after cleaning the inside of the drum 11 with water can also be significantly reduced.

Further, in the present invention, since the lump 4 is produced by using the water contained in the ready-mixed concrete 1, it is not necessary to additionally use water, or even when water is added, the amount of water used is large. Remarkably small amount is required. By using the fluidity reducing agent 2 obtained by crushing a piece of paper such as shredder waste or used paper, it also contributes to the effective utilization of recycled resources.

Further, in the case of transporting the ready-mixed concrete 1 having high fluidity as it is, the transporting means is limited to the agitator wheel 10, but in the present invention, the ready-mixed concrete 1 can be modified into a solid mass 4 and thus manufactured. It is also possible to transport the agglomerate 4 by an ordinary truck or the like. Since the particle size of the agglomerate 4 is small, loading work and unloading work at the time of transportation can be easily performed.

In the above embodiment, the case where the drum 11 is rotated after the fluidity reducing agent 2 is charged has been exemplified, but the fluidity reducing agent 2 is charged in a state where the drum 11 containing the ready-mixed concrete 1 is rotated. It can also be stirred and mixed. Further, for example, in the case where the excess ready-mixed concrete 1 is returned to the inside of the drum 11 after being discharged from the drum 11 once, the fluidity lowering agent 2 is added to the ready-mixed concrete 1 outside the drum 11 and then the ready-mixed concrete 1 flows. It can also be put into the drum 11 together with the sex reducing agent 2. Further, the fluidity reducing agent 2 may be directly charged into the drum 11 without using the bag 3.

For samples of nine ready-mixed concrete (hereinafter referred to as ready-mixed concrete) having different water contents and water contents, the amount of a fluidity reducing agent added suitable for producing a lump was analyzed. Specifically, the experiment of stirring and mixing the ready-mixed concrete and the fluidity-reducing agent inside the drum of the agitator car was performed multiple times by changing the amount of the fluidity-reducing agent for each ready-mixed concrete sample, and the results of the experiments performed multiple times. The amount of the fluidity reducing agent was confirmed to be sufficient for producing a mass from the concrete. Table 1 shows the composition of each ready-mixed concrete sample and the weight of the fluidity reducing agent added, which was appropriate for each ready-mixed concrete sample.

In this experiment, granules (powdered cellulose) formed by pulverizing shredder waste (specific surface area 0.23 m ² by the BET method) with a mill were used as a fluidity reducing agent. The average particle size of the granules was 200 μm, and the specific surface area of the granules by the BET method was 1.6 m ² / g. The true density of the granules was 1.9 g / cm ³ , and the bulk density of the granules was 0.25 g / cm ³ . The porosity of the granules was (1-0.25 / 1.9) × 100≈87%.

As a result of the experiment, it was found that the amount of the fluidity reducing agent suitable for producing the agglomerates greatly depends on the water content of the ready-mixed concrete. That is, it was found that the appropriate amount of the fluidity reducing agent added can be set based on the weight ratio of the weight of the water contained in the ready-mixed concrete to the weight of the fluidity reducing agent. In other words, the amount of cement, aggregate, admixture, etc. contained in the ready-mixed concrete needs little consideration when determining the amount of the fluidity reducing agent added. From the results of the weight ratio (C / A) in Table 1, the weight of the fluidity reducing agent to be stirred and mixed with the ready-mixed concrete is 5% or more and 17% or less, more preferably 8% or more and 13% or less of the weight of the water contained in the ready-mixed concrete. When it is set to about% or less, a mass can be produced without excess or deficiency of the fluidity reducing agent.

Further, in another experiment, the time required for processing 40 liters of ready-mixed concrete was divided into the case of forming a lump by the production method of the present invention and the case where the conventional residual ready-mixed concrete was discharged to the outside of the agitator car and solidified and then crushed. It was compared with the case of making it into a crushed stone. As a result, it was confirmed that the production method of the present invention can reduce the time required for processing the ready-mixed concrete by about 75% as compared with the conventional method of forming crushed stone.

1 Ready-mixed concrete 2 Liquidity reducing agent 3 Bag 4 Bulk body 10 Agitator wheel 11 Drum 12 Opening 13 Mixing blade 14 Input section 15 Discharge section

Claims (5)

By rotating the drum of the agitator car containing the residual ready- mixed concrete and the fluidity-reducing agent which is a granular material having voids in the structure in which the fibers are entangled, the ready-mixed concrete and the fluidity-reducing agent are stirred and mixed. When the lump is formed and the lump is discharged from the opening of the drum to produce the lump which is a mixture using the ready-mixed concrete, the fluidity is reduced by stirring and mixing with the ready-mixed concrete. The amount of the agent added is set based on the weight ratio of the weight of the water contained in the ready-mixed concrete to the weight of the fluidity reducing agent, and the granular material in a state where air is retained in the voids is set. A method for producing a mixture using residual ready-mixed concrete, which comprises stirring and mixing with the ready-mixed concrete. The mixture using the residual ready-mixed concrete according to claim 1 , wherein the weight of the fluidity reducing agent to be stirred and mixed with the ready-mixed concrete is 5% or more and 17% or less of the weight of water contained in the ready-mixed concrete. Production method. The residue according to claim 1 or 2, wherein the specific surface area of the granular material by the BET method is 0.25 m ² / g or more and 100 m ² / g or less, and the porosity calculated by the following formula (1) is 50% or more. A method for producing a mixture using ready-mixed concrete.
(1-The bulk density of the granules / the true density of the granules) × 100 ... (1) The method for producing a mixture using the residual ready-mixed concrete according to any one of claims 1 to 3, wherein the fiber contains a hydrophilic polymer. The method for producing a mixture using the residual ready-mixed concrete according to claim 4 , wherein the hydrophilic polymer is cellulose.

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