JP2015174433A - Separated mixing method and separated mixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce concrete by suppressing increment in stirring torque.SOLUTION: In a separated mixing method, primary mixing is performed by adding primary water and hydraulic powder, such as cement, to aggregate of fine aggregate with partial coarse aggregate added or no coarse aggregate added. In the primary mixing step, there is little mixing water only with primary water added and therefore stirring torque in mixing increases, so that stirring with stirring blades is performed with only partial coarse aggregate added or no coarse aggregate added to suppress increment in the stirring torque compared to the case of a bulky mixing method. Next, upon secondary mixing, the mixture is made into slurry by addition of remaining coarse aggregate and secondary water obtained by removing the primary water from a volume of total mixing water to suppress increment in the stirring torque compared to the case of the bulky mixing method for producing concrete.

Description

  The present invention relates to a divided kneading method and a divided kneading apparatus for producing concrete.

Conventionally, as a method for producing concrete, a batch mixing method is generally employed in which cement and water are added to aggregates and mixed together.
On the other hand, in order to improve the concrete characteristics over the batch mixing method, there has been proposed a divided mixing method in which the blended water to be added is divided into primary water and secondary water and added sequentially. In the divided kneading method described in Patent Documents 1 and 2, first, primary water and cement, which are a part of the total amount of fine aggregate and coarse aggregate to be supplied as aggregate and a part of the mixed water, are added and primary mixing is performed. Then, a capillary-shaped shell-forming layer in which water and cement particles are evenly mixed is formed on the surface of the aggregate. Subsequently, secondary water is added and secondary kneading is performed to produce a slurry-like cement paste to obtain the fluidity of the concrete.

  Here, the capillary state by the primary kneading means that the space between the paste particles having a small ratio of primary water and cement water adhering to the surroundings of the coarse aggregate and fine aggregate, which are aggregates, is filled with water. The state where the bond strength between them becomes the strongest and the mixing energy becomes the maximum. Therefore, the mixing torque by the mixer also increases. Such a paste that has been kneaded into a capillary and then added with secondary water to obtain a total blended water to form a slurry is called a capillary paste.

  In general, in a capillary state of powder such as cement, the binding force between molecules is maximized, and a large amount of energy is required for kneading. Therefore, a stirring torque is large in the primary kneading process. In addition, when the coarse aggregate hits the stirring blade, the cement kneaded material behind it also stirs, and the amount of the stirring kneaded material that the stirring blade bears increases. In comparison, the stirring torque increases. When the amount of fine aggregate is less than the coarse aggregate as a blending condition, or when the coarse aggregate is crushed stone, the stirring torque further increases.

The cement once kneaded in the capillary state has little bleeding even when water is added to form a cement paste in a slurry form. Therefore, if the capillary kneading is performed with the optimum primary water, the bleeding rate does not increase even if secondary water is added to a predetermined blending water to give fluidity, and the effect of divided kneading is exhibited.
By such divided kneading, concrete having excellent characteristics such as little bleeding, excellent fluidity during vibration, and difficult to separate can be produced. In addition, since bleeding is reduced by divided kneading, the bleeding rate is an index for determining whether or not divided kneading has been effectively performed.

  When concrete is produced by the divided kneading method described in Patent Documents 1 and 2 and the like as described above, primary water and cement are added to the fine aggregate and coarse aggregate supplied into the mixer and kneaded. In this case, the stirring torque of the mixer at the time of the primary kneading becomes larger than that of the conventional batch kneading. The reason is that the primary water supplied during the primary kneading is small in part of the blended water, and a capillary cement kneaded material with a high viscosity at a low water cement ratio is interposed between the aggregate particle surface and the particles. This is because the resistance of the stirring blade increases.

For example, FIG. 7 shows the case where the same amount of concrete is produced by the split kneading method and the batch kneading method with the same amount of hydraulic material powder such as fine aggregate, coarse aggregate, compounded water, cement, etc. It is a graph which shows the relationship between the kneading | mixing time (second) in, and the load electric power (KW) which is the stirring torque concerning the stirring blade of a mixer. Mixer used was a volume 2.5 m ³ mixer biaxial forced kneading type.
According to FIG. 7, since the batch mixing method adds and stirs all the blended water together with the fine aggregate and coarse aggregate, the load value of the load power applied to the stirring blade is about 40 KW at the maximum. In the construction method, the total amount of fine aggregate and coarse aggregate was added in the primary kneading step, but since the blended water was only primary water, the stirring torque of the stirring blade increased to about 50 KW. And since it became a slurry state by adding secondary water, load electric power fell. The difference in load power between the conventional batch kneading method and the primary kneading process of the divided kneading method is the increase in load power due to the difference between the cement slurry kneading state and the capillary kneading state. .

Japanese Patent No. 4249176 Japanese Patent No. 4781485

In the split kneading method, the aggregate, primary water, and cement are stirred with a stirring blade in the mixer of the batcher plant used in the conventional batch mixing method, so that the stirring torque of the stirring blade increases by about 25%. The motor, which is the drive source, will run out of output. Therefore, in order to produce concrete with the same amount as the conventional batch mixing method, the equipment such as the motor must be replaced with a larger one and can be produced during the remodeling work period. In addition to the disadvantages such as lack, there was a drawback that the cost was high.
On the other hand, when the split kneading method is used without modifying the conventional batcher plant for batch mixing, the amount of aggregate, cement, and amount of water to be added should be set so that the motor drive does not become excessive. The amount of concrete produced per batch is reduced to 70% to 80% of the batch kneading method, resulting in a disadvantage of poor production efficiency.
These problems have been a major obstacle to the implementation and dissemination of the split kneading method.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a divided kneading method and a divided kneading apparatus capable of efficiently producing concrete while suppressing an increase in stirring torque. .

In the divided kneading method according to the present invention, primary water and a hydraulic substance powder such as cement are added to the aggregate to perform primary kneading, and then secondary water obtained by removing primary water from the total blended water amount is added to the secondary water. In the divided kneading method that is designed to produce concrete by kneading, the primary aggregate is made by adding fine aggregate with a part of coarse aggregate or not containing coarse aggregate as aggregate. It is characterized by mixing and adding the remaining coarse aggregate during the secondary mixing.
According to the divided kneading method according to the present invention, a fine aggregate obtained by adding a part of a coarse aggregate to a fine aggregate or a coarse aggregate is not used, and primary material and hydraulic substance powder such as cement are used. The body is added and primary kneading is performed. At that time, the primary water is a part of the blended water, so the agitation torque tends to increase, but only a part of the coarse aggregate is included or the agitation torque is not included at all. Can be suppressed, and a kneaded product in a capillary state with a small bleeding rate can be produced. After that, secondary mixing is performed by adding the secondary water and the remaining or all of the coarse aggregate. In this process, all the coarse aggregate is contained, but the secondary water is added, so the mixture is mixed. Is in a slurry state, and it suppresses the increase in stirring torque and can be stirred well, making it possible to produce high-strength concrete with a small bleeding rate compared to the one by the batch mixing method. Can be produced to the same extent as when the batch kneading method is used.

Moreover, the coarse aggregate supplied at the time of primary kneading is good also as 70 weight% or less of the whole quantity.
By setting the coarse aggregate supplied at the time of the primary kneading to 70% by weight or less of the total amount, the stirring torque is reduced to the total amount of fine aggregate and coarse aggregate, hydraulic substance powder such as cement and the like. Since mixing torque can be suppressed below the stirring torque when batch mixing is performed, primary mixing can be performed using a mixer used in the batch mixing method.

The divided kneading apparatus according to the present invention produces concrete by adding primary water and hydraulic substance powder such as cement to the aggregate and performing primary mixing, and further adding secondary water and performing secondary mixing. In the primary kneading apparatus, the coarse aggregate first supply means for supplying the mixer with a part of the preset coarse aggregate or not including the coarse aggregate in the primary mixing, and the secondary mixing A coarse aggregate second supply means for supplying the remaining coarse aggregate to the mixer at the time of kneading is provided.
In the divided kneading apparatus according to the present invention, a part of the coarse aggregate preset by the coarse aggregate first supply means is added to the fine aggregate, or a hydraulic substance powder such as cement without including the coarse aggregate At this time, only the primary water is added, so the stirring torque tends to increase, but the coarse aggregate is only partially added or not included at all, so the stirring torque Can be suppressed. In the secondary kneading, the remaining coarse aggregate is charged into the mixer by the coarse aggregate second supply means. However, the mixed water is also in a slurry state because the secondary water is charged, and an increase in stirring torque can be suppressed.

Moreover, according to the division | segmentation kneading apparatus by this invention, the coarse aggregate quantity supplied to a mixer with a coarse aggregate 1st supply means may be zero.
In this case, since the coarse aggregate second supply means supplies the entire amount of coarse aggregate in the secondary mixing process, the aggregate contains only fine aggregate in the primary mixing process, so the mixing torque is only the primary water and stirring torque. In the secondary kneading step, the entire amount of coarse aggregate is added, but secondary water is also added to form a slurry state, and an increase in stirring torque can be suppressed.
Therefore, the divided kneading apparatus according to the present invention can suppress an increase in stirring torque even when using a batcher plant including a conventional mixer used in the batch kneading method. In addition to producing concrete, it can produce high-strength concrete with a low bleeding rate.

 According to the divided kneading method and the divided kneading apparatus according to the present invention, at the time of the primary kneading, the aggregate to be added is only the fine aggregate, or a part of the coarse aggregate is added to the fine aggregate, and the primary water and cement. In addition, it is possible to suppress the increase in the stirring torque in the mixer, and in the secondary mixing, not only the remaining coarse aggregate but also secondary water is added. Since stirring is performed in the added slurry state, an increase in stirring torque can be suppressed and secondary mixing can be performed. Therefore, it is possible to efficiently produce high-strength concrete having a small bleeding rate while suppressing an increase in stirring torque.

It is a flowchart which shows the division | segmentation kneading method by 1st embodiment of this invention. It is a flowchart which shows the division | segmentation kneading method by 2nd embodiment of this invention. It is explanatory drawing which shows the division | segmentation kneading apparatus in embodiment of this invention. It is a block diagram which shows the coarse aggregate input control means by this embodiment. It is a graph which shows the relationship between the load electric power of stirring torque according to the input amount of a coarse aggregate, and a division kneading process. It is a graph which shows the relationship between the input ratio of the coarse aggregate in a primary mixing process, and the load electric power of a primary mixing and a secondary mixing process. It is a figure which shows the relationship between the conventional division | segmentation kneading method and the lump kneading method, and load electric power.

A divided kneading method and a divided kneading apparatus according to an embodiment of the present invention will be described with reference to FIGS.
First, the divided kneading method according to the first embodiment of the present invention will be described based on the flowchart shown in FIG. Concrete produced by the split kneading method exhibits excellent properties such as a low concrete bleeding rate, excellent fluidity during vibration, and high strength that is difficult to separate. The bleeding rate is an important factor as an indicator of the quality of concrete by the split kneading method. In particular, when the split kneading method is used, an excellent concrete having a small bleeding rate compared to the batch kneading method can be obtained.
Moreover, in the divided kneading method according to this embodiment, the coarse aggregate (gravel) is divided and supplied in the primary kneading step and the secondary kneading step, respectively, or the entire amount is supplied in the secondary kneading step. It is characterized by that.

  That is, at the time of the primary kneading, the entire amount of fine aggregate (sand) and a part of coarse aggregate (gravel) are put into the mixer of the batcher plant as aggregate (step S1). The amount of coarse aggregate charged is preferably set so that the stirring torque of the stirring blades in the mixer 20 does not exceed the stirring torque in the batch mixing method. Alternatively, even if the stirring torque of the batch kneading method is exceeded, it is necessary that the torque does not become excessive torque, for example, about the rated torque of the drive motor of the mixer stirring blade.

And the primary water which is a part of all the compounding water is thrown into a mixer (step S2). Next, hydraulic substance powder such as cement is added (step S3), and primary mixing is performed (step S4). In the primary kneading step, cement and primary water are uniformly and efficiently adhered around the fine aggregate and coarse aggregate with an appropriate amount of primary water.
By primary kneading, the space between the particles of cement, which is a powder, is filled with water, and a capillary state in which the bonding force between the particles is maximized is obtained. Capillary low water cement ratio high viscosity cement kneaded material is uniformly interposed between the surface of the aggregate particles and the aggregate particles. Therefore, the stirring torque in the mixer becomes the largest in the primary mixing, but since the amount of coarse aggregate is small, an increase in the stirring torque can be suppressed.

After the primary kneading is completed, the remaining coarse aggregate is put into the mixer (step S5), and secondary water obtained by removing the primary water from the total blended water is added (step S6), and the second kneading is performed by the stirring blade. By mixing, homogeneous concrete having a small bleeding rate can be produced (step S7).
In this case, the total amount of fine aggregate and coarse aggregate is added as the aggregate, and the secondary agitation is performed by the stirring blade, but the total amount of the mixed water is also added to the secondary water to become a slurry state. The stirring torque is not increased compared to the primary kneading step.

As described above, according to the divided kneading method according to the first embodiment, during the primary kneading, the amount of coarse aggregate in the aggregate to be added is partially made, and the primary kneading is performed by adding primary water and cement. In order to mix, the increase in the stirring torque of the stirring blade in a mixer can be suppressed.
Further, in the secondary kneading, since not only the remaining coarse aggregate but also secondary water is added and stirred in a slurry state by a stirring blade, the secondary kneading can be performed while suppressing an increase in stirring torque. Therefore, in the divided kneading method according to the present embodiment, while using the mixer used for the lump kneading method, the amount of the same amount as that of the lump kneading method is suppressed for high-strength concrete having a small bleeding rate while suppressing an increase in stirring torque. Can be manufactured efficiently.

  The divided kneading method according to the present invention is not limited to the above-described embodiment, and can be appropriately changed or replaced without departing from the gist of the present invention. Included in the range. Hereinafter, a divided kneading method and a divided kneading apparatus according to other embodiments and modifications will be described. However, the same reference numerals are used for the same processing steps as those in the flowchart in the first embodiment.

Next, the divided kneading method according to the second embodiment of the present invention will be described with reference to FIG. 2, but the same processing steps as those in the flowchart of the first embodiment are denoted by the same reference numerals, and differences will be mainly described.
In the divided kneading method according to the second embodiment, in the primary kneading step, the coarse aggregate is not charged into the mixer, but the entire amount of fine aggregate and primary water are charged (step S1a, step S2). And cement is thrown in (step S3) and primary kneading is performed (step S4).
In the second embodiment, the mixer to be used is adopted after confirming that a mortar having a high adhesive strength that does not contain coarse aggregate can be kneaded without problems.

  Here, since the surface area of fine aggregate is 95% or more with respect to the total surface area of the aggregate composed of fine aggregate (sand) and coarse aggregate (gravel), the surface area required for mixing cement cement can be secured. The primary kneading can be carried out with only the fine aggregate except the coarse aggregate. In the second embodiment, cement and water uniformly adhere to the surface of the fine aggregate by primary kneading to form a shell, and the cement particles are filled with water to maximize the bonding force between the particles. It becomes a capillary state. Moreover, in the primary kneading step, since coarse aggregate is not included, an increase in the stirring torque of the stirring blade can be suppressed, and a homogeneous kneaded product can be manufactured.

  After the completion of the primary mixing, the entire amount of coarse aggregate is charged into the mixer (step S5), and further secondary water is charged (step S6), and the secondary mixing is performed (step S7). In the secondary mixing process, all the fine aggregates and coarse aggregates are added as aggregates and mixed with a stirring blade, but the total amount of blended water is also added to the secondary water so that it is in a slurry state. Thus, the stirring torque of the stirring blade does not become larger than in the case of the batch mixing method, and the concrete can be manufactured by mixing uniformly.

 As described above, in the divided kneading method according to the second embodiment, in the primary kneading step, the aggregate is only added with fine aggregate, and a part of the blended water is added as the primary water to be kneaded with the cement. In addition, kneaded material in a uniform capillary state can be produced by kneading while suppressing an increase in the stirring torque of the stirring blade. In the secondary mixing step, the entire amount of coarse aggregate is added together with the secondary water, and the secondary mixing is performed in a slurry state. Therefore, the secondary mixing can be performed while suppressing an increase in stirring torque. A small amount of high-strength concrete can be efficiently produced in the same amount by a mixer used in the batch mixing method.

  Here, the terms used in this specification will be described. The hydraulic substance powder refers to a powder that is cured by water and a hydration reaction and becomes a substance that is not soluble in water. Cement is a typical hydraulic material, but there are others that can be employed. That is, among hydraulic substance powders, there are cement having a fast hydraulic reaction, and blast furnace slag, fly ash, silica fume and the like having a relatively slow hydraulic reaction. Limestone fine powder and the like are those that do not have a hydraulic reaction. These are admixtures. An appropriate hydraulic substance other than the cement can be mixed with the cement and used as a hydraulic substance as a whole.

  The hydraulic substance powder in this embodiment is made of cement alone, or in addition to cement, at least one or more kinds of blast furnace slag, fly ash, silica fume, and limestone fine powder are added and mixed. Any one of mixed powders is used. Therefore, a hydraulic substance powder made of a mixed material may be stored in the admixture powder silo instead of cement. In this specification, the powder is called a hydraulic substance powder including the case of cement alone.

  Shell making is a mixture of a hydraulic substance powder mixed with water to make a strong binding force between powder particles at the interface of the aggregate composed of fine aggregate S and coarse aggregate G. It shall mean the layer adsorbed as a shell.

Next, the divided kneading apparatus 1 for carrying out the divided kneading method according to the first and second embodiments described above will be described with reference to FIGS.
FIG. 3 shows a divided kneading apparatus 1 according to an embodiment of the present invention. A divided kneading apparatus 1 shown in FIG. 3 is a batcher plant for producing concrete by a divided kneading method. For example, a cement silo 2 for storing cement as hydraulic substance powder supplied from a tank truck is used. And an admixture powder silo 3 for storing admixture powder contained in the hydraulic substance powder. The cement and the admixture powder supplied from the hopper of the cement silo 2 and the hopper of the admixture powder silo 3 are supplied to the hydraulic substance powder measuring hopper 5 via the screw feeder 4.

  Further, sand, which is fine aggregate conveyed by the overhead crane 7 or the like, is stored in the fine aggregate storage hopper 8 and further supplied to the fine aggregate weighing hopper 9 via a belt conveyor. Furthermore, gravel, which is coarse aggregate transported by the overhead crane 7 or the like, is stored in the coarse aggregate storage hopper 10 and supplied to the coarse aggregate weighing hopper 11 via a belt conveyor. Further, the water stored in the water tank 13 is stored in the water measuring hopper 14 (water measuring means). The admixture stored in the admixture tank 16 is supplied to the water measurement hopper 14 via the measurement tank 17.

  In these hydraulic substance powder measuring hopper 5, fine aggregate measuring hopper 9, coarse aggregate measuring hopper 11, and water measuring hopper 14, each measured material is selectively supplied to the mixer 20 by the control means 18 and mixed. Is supposed to do. As the mixer 20, a “biaxial forced kneading mixer” was used as an example. The coarse aggregate measuring hopper 11 stores, for example, a coarse aggregate G that is a total amount for split mixing of concrete, and the coarse aggregate G is a primary coarse bone to be charged at the time of primary mixing. The gate is controlled to open and close by weighing with a load cell (not shown) so as to be divided into the material G1 and the secondary coarse aggregate G2 to be charged when the secondary kneading is performed and sequentially supplied to the mixer 20. Moreover, coarse aggregate G = primary coarse aggregate G1 + secondary coarse aggregate G2.

  The water metering hopper 14 stores, for example, blended water (total water) W that is the total amount for the concrete mixing and mixing, and the blending water W is supplied to the aggregate for primary mixing. The valve is controlled to open and close by metering with a load cell (not shown) so as to be divided into primary water W1 and secondary water W2 for secondary kneading and sequentially supplied to the mixer 20. Moreover, the blended water W = primary water W1 + secondary water W2.

In FIG. 4, the control unit 18 includes an aggregate supply unit 22, a hydraulic substance powder supply unit 23, and a water supply unit 24. The aggregate supply means 22 measures a predetermined amount of sand in the fine aggregate measuring hopper 9 and supplies it to the mixer 20, and measures a part of gravel G1 in the total amount during the primary mixing. The coarse aggregate first supply means 27a for supplying to the mixer 20 and the coarse aggregate second supply means 27b for measuring and supplying the remaining gravel G2 to the mixer 20 during the secondary mixing.
Further, the aggregate amount setting means 28 outputs a signal instructing to supply the mixer 20 with all the amount of sand and a part of preset gravel G1 for the primary mixing, and further the secondary mixing. In the mixing step, a signal instructing to supply the remaining gravel G2 to the mixer is output, and the sand and gravel G1 and the remaining gravel G2 are supplied to the mixer 20, respectively.

Further, the hydraulic substance powder supply means 23 measures the cement or admixture powder with the hydraulic substance powder measuring hopper 5 and supplies it to the mixer 20 during the primary kneading.
In the water supply means 24, the water amount setting means 25 sets the optimal primary water that minimizes the bleeding rate in the primary mixing step to the primary water W1, and the secondary water W2 from the blended water W to the primary water W1. Set to the amount excluding.

  Some gravel G1 in this embodiment is arbitrarily set in the aggregate amount setting means 28 in a range where the maximum value of the stirring torque does not exceed the maximum stirring torque of the batch mixing method in the primary mixing step. In this case, a part of the gravel G1 may be set to 0%, and the entire amount (100%) may be supplied to the mixer as the remaining gravel G2 during the secondary mixing. However, the distribution ratios of gravel G1 and G2 are not 0 to each other so that there is no imbalance between the stirring torque in the primary mixing of the mixer 20 and the stirring torque in the secondary mixing. It is more preferable to set to.

The divided kneading apparatus 1 according to the present embodiment has the above-described configuration, and the divided kneading method according to the first and second embodiments will be described along the flowcharts shown in FIGS. 1 and 2.
When the concrete is produced by the divided kneading apparatus 1 according to the present embodiment, the supply amount of the required amount of sand and gravel is determined, and the stirring torque is the maximum of the batch kneading method when stirring with the stirring blade in the mixer 20. A part of the gravel G1 to which the total amount of gravel is supplied by primary mixing and the remaining gravel G2 to be supplied by secondary mixing are set in advance so as not to exceed the stirring torque.

  Then, according to the instruction signal from the aggregate amount setting means 28, the fine aggregate measuring hopper 9 and the coarse aggregate measuring hopper 11 require the instruction signals from the fine aggregate supplying means 26 and the coarse aggregate first supplying means 27a. An amount of sand and gravel G1 are weighed and put into the mixer 20 (step S1). Next, the primary water W1 determined by the water amount setting means 25 is measured by the water measuring hopper 14 according to an instruction signal from the primary water supply means 29 and supplied to the mixer 20 (step S2).

  Next, the hydraulic substance powder containing the admixture and the like in the cement whose dosage is set by the hydraulic substance powder supply means 23 is measured by the hydraulic substance powder measuring hopper 5 and supplied to the mixer 20 ( Step S3), primary mixing is performed (step S4). At this stage, since the primary water W1 has an optimum primary water amount, water and cement powder are sufficiently adhered to the surface of the aggregate stirred by the mixer 20 to form a shell, and between the aggregate particles. It changes to the capillary state where the binding force is maximized.

Moreover, since the amount of gravel G1 supplied is a part of the total amount, the stirring torque of the stirring blades in the mixer 20 can be suppressed to a level that does not exceed the maximum torque (for example, 40 KW) in the batch mixing method. .
When the primary water W1 is the optimum primary water amount, the proportion of water and cement powder adhering to the surface of each aggregate increases, the insufficiently attached phencular state decreases, and the capillary state can be increased. Therefore, water and cement are sufficiently adhered around each aggregate, and most of them are in a capillary state to form a shell-forming layer, and the rate of capillary paste is improved.

  Then, after the primary mixing is completed, the secondary water W2 is measured by the secondary water supply means 30 with the water measuring hopper 14 and charged into the mixer 20, and the remaining set by the coarse aggregate second supply means 27b. The gravel G2 is measured by the gravel metering means 11 and charged into the mixer 20 (step S5, step S6), and the secondary mixing is performed (step S7). At the time of secondary kneading, not only the remaining gravel G2 but also secondary water W2 is added and stirred with a stirring blade in a slurry state, and therefore, secondary kneading can be performed while suppressing an increase in stirring torque. Therefore, while using a batcher plant equipped with the mixer 20 used for the batch mixing method as the split mixing device 1, the increase of the stirring torque is suppressed, and the high-strength concrete with a small bleeding rate is batch-mixed. Can be produced efficiently in the same amount.

When the divided kneading method according to the second embodiment described above is performed using the divided kneading apparatus 1 according to the present embodiment, the coarse aggregate set by the coarse aggregate first supply means 27a is set to 0% and is roughly mixed into the mixer. The total amount of fine aggregate and primary water W1 are charged without adding the aggregate (step S1, step S2). And cement is thrown in (step S3) and primary kneading is performed (step S4).
At this time, since the gravel (coarse aggregate) is not included in the mixer 20, in the first mixing step in which only the total amount of fine aggregate, cement, and primary water are stirred, stirring of the stirring blade is performed even if the amount of blended water is small. The kneading can be performed while suppressing the torque to be equal to or less than that in the batch kneading method, and a kneaded product in a homogeneous capillary state can be produced.

  After the completion of the primary mixing, the entire amount of coarse aggregate G set by the coarse aggregate second supply means 27b is charged into the mixer 20 (step S5), and further secondary water W2 is charged (step S6). Mixing is performed (step S7). In the secondary kneading step, all the fine aggregates and coarse aggregates are added as aggregates and kneaded with a stirring blade, but the mixed water is also added to the secondary water W2 so that it becomes a slurry state. The stirring torque of the stirring blade does not become larger than in the case of the batch kneading method, and high strength concrete can be manufactured by kneading homogeneously.

 As described above, according to the divided kneading apparatus 1 according to the present embodiment, in the primary kneading step, the primary kneading is performed without adding gravel only partly G1 or not at all, so even if there is little primary water W1, the stirring blade A kneaded product in a homogeneous capillary state can be produced by kneading while suppressing an increase in stirring torque. Also, in the secondary mixing process, the remaining gravel G2 or the entire amount of gravel G is added together with the secondary water W2 to perform secondary mixing in a slurry state. It is possible to produce high-strength concrete with a small bleeding rate. Moreover, the same amount of concrete as the batch mixing method can be efficiently produced by the drive motor of the mixer used in the batch mixing method.

The divided kneading apparatus 1 according to the above-described embodiment includes the aggregate amount setting means 28, the coarse aggregate first supply means 27a, and the coarse aggregate second supply means 27b, and is an integrated container as the coarse aggregate measuring hopper 11. Measuring means, and a part of the gravel G1 and the remaining gravel G2 set by the aggregate amount setting means 28 are sequentially supplied by the instruction signals from the coarse aggregate first supply means 27a and the coarse aggregate second supply means 27b. The coarse aggregate weighing hopper 11 is supplied to the mixer 20 sequentially, but the present invention is not limited to such means.
For example, as a first modification, the entire amount of gravel is put into the coarse aggregate weighing hopper 11, and at each supply, by the instruction signal of the coarse aggregate first supply means 27a and the coarse aggregate second supply means 27b, in a load cell or the like The gravel amounts G1 and G2 may be sequentially fed into the mixer 20 by weighing.

  As a second modification, the coarse aggregate weighing hopper 11 stores a part of the coarse aggregate G1 and the remaining coarse aggregate G2 in two rooms, and stores the coarse aggregate first supply means 27a and the coarse bone. In accordance with an instruction signal from the material second supply means 27b, a part of the gravel G1 and the remaining gravel G2 are weighed when being supplied to each room of the coarse aggregate measuring hopper 11 and sequentially supplied to the mixer 20. It may be.

Next, a test example of the divided kneading method used in each embodiment described above will be described with reference to FIGS.
The components shown in Table 1 below are used for the components used in the batch kneading method and the divided kneading method as the concrete composition used in the test. The mixer used in each test was a biaxial forced kneading type, and the mixer capacity was 2.5 m ³ / batch. As the stirring torque of the stirring blade, 2.5 m ³ was mixed in the mixer, and the load power value (KW) of the current value was measured.

FIG. 5 shows a test example of the divided kneading method according to this embodiment. In the primary mixing step in the divided mixing method according to the present embodiment, the ratio of gravel (coarse aggregate) to be added to the mixer is set to 0%, 25%, 50%, 75%, 100%. The vertical axis represents the stirring torque of the stirring blade as load power (KW), and the horizontal axis represents the mixing time in each step of primary mixing and secondary mixing.
Grain (coarse aggregate) G1 input ratio in secondary mixing when the input ratio of gravel (coarse aggregate) G1 in primary mixing is 0%, 25%, 50%, 75%, 100% Are 100%, 75%, 50%, 25%, and 0%, respectively. Therefore, the ratio of gravel to be added in the primary mixing step is G1 = 25%, 50%, 75% is the first example, G1 = 0% is the second example, and 100% is the divided mixing in the prior art. It is a mixed method.

  Referring to FIG. 5, in the conventional divided kneading method (gravel: 100%), the load power of the stirring torque in the primary kneading process is 50 KW at maximum, and the load of the stirring torque is 8 KW than that of the batch kneading method (42 KW). About big. On the other hand, in the first embodiment (gravel: 25%, 50%, 75%), the load power of the stirring torque in the primary mixing step is about 20 to 42 KW, which is about the same as the batch mixing method. In the second embodiment (gravel: 0%), the load power of the load torque in the primary kneading step is about 16 to 25 kW, and the load power of the load torque in the secondary kneading step is about 42 KW or less. .

  Therefore, according to the divided kneading method in the first embodiment and the second embodiment, the load power of the stirring torque is suppressed to the same level or less as that in the lump kneading method, and an excessive load is not applied. It is not necessary to change to a larger one or to reduce the amount of concrete material to be charged to about 70 to 80% of the batch mixing method, and the same amount of concrete can be produced. Moreover, since the split kneading method is used, high strength concrete can be efficiently produced with a smaller bleeding rate than the batch kneading method.

Moreover, the graph shown in FIG. 6 shows the input ratio to the total coarse aggregate in the primary mixing step and the load power (maximum value) in the primary mixing and the secondary mixing from the test results of the present example shown in FIG. ) Is a graph expressed as a relationship with.

In FIG. 6, the coarse aggregate to be charged in the primary kneading step was changed from 0% to 25%, 50%, 75%, and 100%, and the primary kneading was performed under the same conditions. In this case, the maximum load torque according to the input amount G1 of the coarse aggregate in the primary kneading step was measured with 42 KW being the maximum load torque in the batch kneading step as an upper limit. As a result, when the amount G1 of the coarse aggregate in the primary kneading exceeds 70%, the upper limit of 42 KW was exceeded.
Therefore, under this test condition, the maximum load torque of the stirring torque was 42 KW or less, which is the upper limit, when the proportion G1 of coarse aggregate in the primary mixing was 70% or less. In this case, the input amount G2 of the coarse aggregate in the secondary kneading step is 30% or more.

Therefore, in this embodiment, the amount of coarse aggregate charged is 70% or less in the primary mixing step and 30% or more in the secondary mixing step, so that the stirring torque of the stirring blade is the upper limit of the batch mixing method. Dividing and kneading can be performed with a conventional mixer without exceeding the value.
However, these test examples are only examples, and the upper and lower limit values of the amount G1 of the coarse aggregate charged by the primary mixing and the amount G2 of the coarse aggregate at the time of the secondary mixing are determined by the mixer of the virtual plant to be used. It varies depending on the volume, the magnitude of the output of the drive motor, the amount of fine aggregate, coarse aggregate, hydraulic substance powder such as cement, and the amount of mixed water. The present invention is not limited to the upper limit of the amount of coarse aggregate input according to the above-described test example. One example is a method in which the supply amount G1 of the coarse aggregate in the primary mixing step is set to 0, and the supply amount G2 of the coarse aggregate is set to 100% (total amount) in the secondary mixing step.

In addition, in the divided kneading method according to the first and second embodiments, regarding the addition of aggregate and primary water during the primary mixing, and the addition of the remaining coarse aggregate and secondary water during the secondary mixing It is not limited to the procedure shown in FIG.1 and FIG.2, The injection | throwing-in procedure can be set arbitrarily. That is, the aggregate and primary water may be charged simultaneously, the aggregate may be charged after the primary water is charged, and the remaining coarse aggregate and secondary water may be charged simultaneously, Needless to say, the remaining coarse aggregate may be charged after the secondary water is charged.
Further, in the above-described embodiment of the present invention, in the previous stage of the primary kneading step, only the fine aggregate or a part of the coarse aggregate is added to the fine aggregate, and the primary water is added to the mixer and kneaded. The step of uniformly adhering water to the entire circumference of the fine aggregate and coarse aggregate can be separated from the primary mixing step as the adjustment mixing step.

DESCRIPTION OF SYMBOLS 1 Split kneading apparatus 2 Cement silo 3 Admixture powder silo 5 Hydraulic substance powder measurement hopper 9 Fine aggregate measurement hopper 11 Coarse aggregate measurement hopper 14 Water measurement hopper 18 Control means 20 Mixer 22 Aggregate supply means 23 Hydraulic Substance powder supply means 24 Water supply means 25 Water amount setting means 26 Fine aggregate supply means 27a Coarse aggregate first supply means 27b Coarse aggregate second supply means 28 Aggregate amount setting means 29 Primary water supply means 30 Secondary water Supply means

In the divided kneading method according to the present invention, primary water and a hydraulic substance powder such as cement are added to the aggregate to perform primary kneading, and then secondary water obtained by removing primary water from the total blended water amount is added to the secondary water. mixing by performing, in divided kneading method was to produce a concrete, also of the perform primary kneading was charged plus a part of the fine aggregate to coarse aggregate as aggregate, the two The remaining coarse aggregate is added at the time of the next mixing.
According to division kneading method according to the present invention, also added a portion of the coarse aggregate to fine aggregate as aggregate of were charged, kneaded primary adding hydraulic material powders such primary water and cement At that time, the primary water is a part of the blended water, so the stirring torque is likely to increase.However, since only a portion of the coarse aggregate is included , the increase in the stirring torque can be suppressed, and the bleeding rate A small capillary kneaded product can be produced. After that, secondary mixing is performed by adding secondary water and the remaining coarse aggregate. In this process, the total amount of coarse aggregate is contained, but secondary water is added, so the kneaded product is a slurry. It is possible to produce high-strength concrete with a reduced bleeding rate compared to the batch mixing method by mixing well and suppressing the increase in stirring torque, and the production amount of concrete is batch It can be manufactured to the same extent as when the kneading method is used.

The divided kneading apparatus according to the present invention produces concrete by adding primary water and hydraulic substance powder such as cement to the aggregate and performing primary mixing, and further adding secondary water and performing secondary mixing. in split mixing apparatus so as to, during primary kneading, and coarse aggregate first supply means for supplying to the mixer by the addition of part of the preset coarse aggregate, when the secondary kneading, the remaining crude Coarse aggregate second supply means for supplying the aggregate to the mixer is provided.
In the divided kneading apparatus according to the present invention, a part of the coarse aggregate preset by the coarse aggregate first supply means is added to the fine aggregate to add hydraulic substance powder such as cement to perform primary mixing. but it tends stirring torque is increased since the this time mixed water introduced only to the primary water, coarse aggregate can suppress an increase in the addition of only part Runode, stirring torque. In the secondary kneading, the remaining coarse aggregate is charged into the mixer by the coarse aggregate second supply means. However, the mixed water is also in a slurry state because the secondary water is charged, and an increase in stirring torque can be suppressed.

According to the divided kneading method and the divided kneading apparatus according to the present invention, during the primary kneading, a part of the coarse aggregate is added to the fine aggregate as the aggregate to be added, and the primary substance and hydraulic substance powder such as cement are added. Since the body is mixed with the primary kneading, the increase in the stirring torque in the mixer can be suppressed, and in the second kneading, stirring is performed in a slurry state in which not only the remaining coarse aggregate but also secondary water is added. Therefore, secondary kneading can be performed while suppressing an increase in stirring torque. Therefore, it is possible to efficiently produce high-strength concrete having a small bleeding rate while suppressing an increase in stirring torque.

Claims (4)

Add primary water and hydraulic substance powder such as cement to the aggregate and mix it first, and then add the secondary water from which the primary water is removed from the total amount of mixed water and then mix the concrete. In the divided kneading method that was designed to be manufactured,
As the aggregate, a mixture obtained by adding a part of coarse aggregate to fine aggregate or not containing coarse aggregate is subjected to primary mixing, and the remaining coarse aggregate is left during the secondary mixing. Divided kneading method, characterized by the addition of   The divided kneading method according to claim 1, wherein the coarse aggregate supplied during the primary kneading is 70% by weight or less of the total amount. In a divided kneading device that adds primary water and hydraulic substance powder such as cement to the aggregate and mixes it first, then adds secondary water and mixes it secondarily to produce concrete. ,
In the primary kneading, a coarse aggregate first supply means for supplying the mixer with a part of a preset coarse aggregate or not including the coarse aggregate,
A divided kneading apparatus comprising a coarse aggregate second supply means for supplying the remaining coarse aggregate to the mixer during the secondary kneading. 4. The divided kneading apparatus according to claim 3, wherein the amount of coarse aggregate supplied to the mixer by the coarse aggregate first supply means is zero.

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