JP5361405B2 - Manufacturing method of recycled aggregate for concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing recycled aggregate for concrete that enables stabilization and laborsaving in quality control in the production by establishing a quality control procedure for the recycled aggregate by means of pursuing the correlation between production conditions and quality of the aggregate in the mechanical treatment (mechanical grinder) where the raw material, concrete debris is subjected to crushing and grinding. <P>SOLUTION: A mechanical grinder having partition plates to form a plurality of grinding rooms affixed to the rotating shaft in a drum body and grinding media filled in the grinding rooms is used. When a variable R indicates a ratio of rotation speed of the partition plates/feed rate of raw materials, the production is carried out in the range of R of 0.67-1.88 for coarse recycled aggregate and in the range of R of 1.00-4.67 for fine recycled aggregate (provided that the quality is based on the density of absolute-dry base and water absorption coefficient ). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a recycled aggregate for concrete, in particular, a quality control method, for producing a recycled aggregate using a concrete block generated when a concrete structure is dismantled as a raw material.

  As a technology for reducing the environmental load, efforts have been made to produce recycled aggregates from dismantled concrete blocks as raw materials and reuse them as structural concrete for buildings.

  The Ministry of Economy, Trade and Industry established JIS (Japanese Industrial Standards) for “Recycled Aggregate H for Concrete” on March 20, 2005, in order to promote recycling of such concrete blocks.

Among them, recycled aggregates are classified, and the classified recycled aggregates H, M, and L are as follows.
Recycled aggregate H: Aggregate produced by advanced processing such as crushing, grinding, and classification. Used for general purpose concrete.
Recycled aggregate M: An aggregate produced by processing such as crushing and grinding. Used for concrete that is not affected by drying shrinkage or freezing and thawing, such as piles and foundation beams.
Recycled aggregate L: aggregate produced by crushing. Used for concrete where high strength and durability are not required.

  In order to achieve the JIS standard for recycled aggregates including those for construction, it is necessary to ensure long-term durability such as the effect on the corrosion of reinforcing bars in concrete and the presence or absence of concrete strength reduction due to freezing.

  Established recycled aggregate H is a concrete aggregate manufactured by performing high-level processing such as crushing, grinding, and classifying concrete lump generated by demolition of buildings, etc. The recycled aggregate has the same quality as the aggregate.

By the way, as a manufacturing method of the recycled aggregate, a method of heating concrete rags as a raw material in advance to weaken the adhesion mortar as in Patent Document 1 below, or a method of adhering to natural aggregate as in Patent Document 2 For removing the mortar content and cement hydrate, there is one using a saddle type eccentric rotor device constituted by a saddle type outer peripheral wall and a rotor that rotates eccentrically in the outer peripheral wall.
JP 2003-26459 A Japanese Patent Laid-Open No. 2002-210380

  Patent Document 1 discloses an aggregate recycling method in which a heat treatment using hot air is performed on a concrete crushed material obtained by crushing a concrete lump, and then the aggregate is separated and regenerated from the concrete crushed material. Then, the above heat treatment is performed on a concrete crushed material having a maximum dimension of 5 mm or more.

  According to Patent Document 1, since heat treatment with hot air is performed on a concrete crushed material having a maximum size of 5 mm or more, impurities such as fine particles of less than 5 mm and soil are crushed during the heating. It is possible to prevent clogging in the space between the materials. Therefore, the heating time of the concrete crushed material can be shortened. In addition, since it can be heated to a uniform temperature over the entire concrete crushed material, it is possible to reliably separate hard cement paste etc. from fine aggregates and coarse aggregates by, for example, grinding after heating. can do. In other words, it is possible to regenerate aggregates such as fine aggregates and coarse aggregates having excellent quality from which hardened cement paste and the like have been reliably removed.

  Patent Document 2 discloses a separation method for rubbing a concrete block between an inner surface of an outer peripheral wall and an outer surface of a cylindrical rotor supported so as to be eccentrically rotatable in the outer peripheral wall and for separating a water-containing deposit from an aggregate. In an eccentric rotor device in which a combined passage is formed, a substantially lattice-shaped stirrer having required strength and hardness is provided on the outer surface of the rotor 3 with a gap between the outer surface and the inner surface of the outer peripheral wall. It is fitted.

  According to Patent Document 2, a high-quality recycled aggregate is obtained by loosely fitting a substantially lattice-shaped stirrer to the outer surface of the eccentric rotor with an interval between the outer surface and the inner surface of the outer peripheral wall. It can be obtained at low cost.

Patent Document 3 below describes a method of spraying water on the aggregate surface and judging the quality from the color tone.
JP 2006-167646 A

  This patent document 3 describes an eccentric rotor type vertical crusher as a means for stably obtaining high-quality recycled aggregate in a concrete waste material recycling treatment facility using an eccentric rotor type vertical crusher. After spraying water on the discharged recycled aggregate for a predetermined time, the color tone of the aggregate is photographed with a CCD camera, the mortar adhesion amount as quality information is estimated from the color tone data, and based on the estimated mortar adhesion amount The outer cylinder of the vertical crusher is moved up and down, and the width of the gap between the lower end of the vertical crusher and the vertical ring provided at the lower part of the rotor is changed so that the residence time of the concrete block that is the raw material for recycled aggregate in the vertical crusher Is to adjust.

  As a result, the mortar from the concrete block can be sufficiently removed regardless of the operating conditions of the vertical crusher, and a high-quality recycled aggregate B can be obtained stably.

  Patent Document 1 and Patent Document 2 are not clearly shown as a quality control method of recycled aggregate for satisfying required quality.

  Patent Document 3 mentions quality control of recycled aggregate, but some results are shown for the correlation between manufacturing conditions and aggregate quality, but this is only a qualitative expression. It is not clearly shown.

  In general, quality control in the production of recycled aggregates depends on the quality of the concrete used in the building to be demolished, so it is necessary to confirm by experiment each time to derive the production conditions. However, quality control in the production of recycled aggregates so far has been to visually observe the aggregates immediately after production and change the production conditions (mainly the input amount) according to the degree of adhesion mortar peeling. It corresponds.

  The reason for this is that, as described above, in order to confirm by experiment each time the production conditions are derived, the test of density and water absorption, which is a quality index, takes time, the results of which will be revealed at a later date. is there. Therefore, it has been a problem that the manufacturing is not necessarily performed under the optimum conditions.

  The object of the present invention is to eliminate the inconveniences of the conventional example, and to obtain a correlation between the production conditions and the aggregate quality when obtained by a mechanical treatment (mechanical grinding machine) that uses crushing and polishing with concrete glass as raw material. It is an object of the present invention to clarify a quality control method for recycled aggregate, and to provide a method for manufacturing recycled aggregate for concrete that can stabilize and save labor in quality control in manufacturing.

  In order to achieve the above object, the present invention provides a partitioning member provided with a partition member for forming a plurality of grinding chambers on a rotating shaft in a drum body, and using a mechanical grime apparatus in which a loading material is loaded in the grinding chamber. The number of rotations of the member / the amount of raw material input is a variable R. The recycled coarse aggregate has a variable R of 0.67 to 1.88, and the recycled fine aggregate has a variable R of 1.00 to 4.67 (however, the quality is The gist is to produce it as a range of absolute dry density / water absorption.

  According to the first aspect of the present invention, the quality control technique of recycled aggregate obtained by mechanical processing (mechanical grinding machine) that uses crushing and polishing using concrete glass as a raw material has been clarified. In addition, concrete gravel here means what crushed the demolition concrete lump easily to the particle size of about 40 mm or less with the crusher in the demolition site | part or the intermediate treatment facility.

In the mechanical grinding machine, the input raw material is subjected to crushing and grinding by the partition plate. Therefore, the following manufacturing conditions were focused on.
(1) Number of rotations of partition plate (2) Input amount of raw material Here, it is estimated that the more contact opportunities between the raw material and the partition plate, the more the adhesion mortar is peeled off and the quality of recycled aggregate is improved. Variable R).
Variable R: number of rotations of partition plate / raw material input amount

As described above, according to the method for producing a recycled aggregate for concrete according to the present invention, the following effects can be obtained by deriving a relational expression between production conditions and aggregate quality.
(1) Optimal manufacturing conditions can be obtained with a small number of samples, and therefore quality control during manufacturing can be saved.
(2) Manufacture according to the required quality of recycled aggregate is possible.
(3) The limit point of the quality of the recycled aggregate can be derived according to the quality of the raw material. In other words, it is possible to determine the selection of the demolished building that is the raw material.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, a mechanical grinding machine as shown in FIG. 1 is used as a mechanical process for adding crushing and grinding.

  This mechanical grinding device is provided with an introduction port 1 for taking in the material to be ground at one end as disclosed in Japanese Patent No. 3261125, Japanese Patent Application Laid-Open No. 2006-205118, and Japanese Patent Application Laid-Open No. 2008-104910. A drum body 3 provided with a discharge port 2 for discharging the ground material after grinding at the end, a rotating shaft 4 penetrating through the drum body 3 in the axial direction of the drum body 3, and the rotating shaft 4 A partition member 5 which is attached to the rotary shaft 4 at an inclined angle to partition the inside of the drum body 3 and form a plurality of grinding chambers 6 communicating with each other in the drum body 3, and the grinding chamber 6 and a grinding loading material 8 which is a required number of metal balls loaded in 6, and the grinding loading material 8 repeatedly rises and falls as the partition member 5 rotates. It reciprocates in the axial direction of the shaft 4.

  First, when a ground material is introduced from the inlet 1, the ground material enters the first grinding chamber 6 counted from the upstream side. Since the partition member 5 is inclined with respect to the rotation shaft 4, the partition member 5 quickly repeats the forward tilt state and the rear tilt state in the axial direction of the rotary shaft 4. As a result, the material to be ground is strongly bounced up and down and then dropped, the rising and falling are repeated, and the reciprocating motion is quickly performed in the axial direction of the rotating shaft 4. Thereby, the material to be ground is ground in the first grinding chamber 6.

  When grinding is performed to some extent in the first grinding chamber 6, the grinding object is large enough to pass through a conduction hole 7 (see FIG. 2) provided in the first partition member 5 counting from the upstream side. It becomes.

  The object to be ground having such a size passes through the conduction hole 7 and enters the second grinding chamber 6 (into the second grinding chamber 6. The loading material 8 is strongly bounced up by colliding with two inclined partition members 5 and then dropped, and the rising and falling are repeated, and the reciprocating motion is quickly performed in the axial direction of the rotary shaft 4. Thereby, the collision between the material to be ground and the charging material 8 for grinding is performed uniformly and intensely, and the grinding process is efficiently performed in the second grinding chamber 6, and the particle size of the material to be ground is further increased. Get smaller.

  When the grinding process is performed to some extent in the second grinding chamber 6, the grinding object has a size capable of passing through the conduction hole 7 provided in the second partition member 5 when counted from the upstream side. The object to be ground having such a size passes through the conduction hole 7 and enters the third grinding chamber 6. The same processing as in the second milling chamber 6 is also performed in the third, fourth,... Milling chamber 6, and the material to be ground is milled until a desired size is obtained.

  The ground material having a desired particle diameter is discharged from the discharge port 2 of the drum body 3. Thus, the grinding process is completed.

  Although what is shown in Japanese Patent Application Laid-Open No. 2006-205118 is omitted, a plurality of bits project from the surface of the partition member 5, and the bits project from the surface of the partition member 5. When the grinding load 8 such as a ball hits the bit, the friction with the surface of the partition member 5 is reduced, the replacement frequency of the partition member 5 can be reduced, the work efficiency is improved, and the equipment cost is reduced. Can be achieved.

  The one disclosed in Japanese Patent Application Laid-Open No. 2008-104910 has a plurality of notches formed at intervals along the outer peripheral edge in order to facilitate bit replacement work of Japanese Patent Application Laid-Open No. 2006-205118. A U-shaped block 9 is fitted into the cut portion.

  The drum body 3 is formed by combining an upper half surface constituting the upper half of the cylinder and a lower half surface constituting the lower half of the cylinder, and the entire upper half surface can be opened. Yes.

  The rotary shaft 4 is disposed so as to penetrate the drum body 3 in the axial length direction, and hydraulically driven motors are connected to both left and right ends thereof, respectively, and are configured to rotate by driving these two motors. Has been.

  When a motor is connected only to one end portion of the rotating shaft 4, the center shaft is eccentric at the other end portion due to the weight of the center shaft itself or a load received from the ball during rotation, and thus a large driving force is required to prevent this. However, by rotating the rotating shaft 4 by driving a motor connected to both ends thereof, the eccentricity of the end portion of the central shaft can be suppressed, so that power consumption can be reduced. In addition, the installation area of the drive mechanism can be reduced.

  In addition, since the hydraulic drive motor is resistant to shock load and has a continuously variable speed, the rotational speed of the rotary shaft 4 can be easily adjusted, and can be appropriately adapted to the type of object to be ground. Become. However, it is also possible to use an electric motor.

  As an example, the drum body 3 is a drum having an outer diameter φ1500 (mm), an inner diameter φ1300 (mm), and a length L4000 (mm). The drum itself does not rotate, and only the rotating shaft 4 rotates. The partition member 5 provided on the rotating shaft 4 is an inclined disk having an outer diameter φ1400 (mm). The width of the conduction hole 7 formed in the partition member 5 is 45 mm when the coarse aggregate is manufactured and 15 to 35 mm when the fine aggregate is manufactured. These are used interchangeably. Note that an iron ball having an outer diameter of 50 to 70 mm was used as the loading material for grinding, and the porosity in the drum body 3 when this iron ball was loaded into the drum body 3 was set to 40%.

  In the present invention, when such a mechanical grinding machine is used, the rotation speed / raw material input amount of the partition member is set as a variable R, and the recycled coarse aggregate has a variable R of 0.67 to 1.88. Aggregates are manufactured with a variable R in the range of 1.00 to 4.67 (provided that the quality is absolutely dry density and water absorption).

In the mechanical grinding machine, the input raw material is subjected to crushing and grinding by the partition plate. Therefore, the following manufacturing conditions are focused on.
(1) Number of rotations of partition plate (2) Input amount of raw material Here, it is estimated that the more contact opportunities between the raw material and the partition plate, the more the adhesion mortar is peeled off and the quality of recycled aggregate is improved. Variable R).
Variable R: number of rotations of partition plate / raw material input amount

Next, examples will be described.
1. Experiment plan (1) Properties of raw materials For Experiment I, 100 t of dismantled concrete that was unobtained in the dismantled building that was carried in during a certain period was used as a raw material in an intermediate treatment plant.

  In Experiment II, Experiment III, and Experiment IV, all were demolished concrete obtained from a specific building (hereinafter referred to as Building A). The physical properties of the raw aggregate obtained by removing the concrete core collected from the building A by hydrochloric acid treatment are shown in Table 1 below.

  As a comparative example, an example of the production of recycled aggregates in the past is also shown. The raw coarse aggregate of building A was crushed stone, but its quality was equivalent to that of the river gravel of the comparative example. On the other hand, the quality of the raw fine aggregate was smaller than that of the comparative example in terms of absolute dry density and large water absorption. In the production of recycled aggregate, the above demolished concrete was crushed and adjusted to a predetermined particle size range.

(2) Recycled Aggregate Manufacturing Method Recycled aggregate is manufactured using the mechanical grinding machine shown in FIG. 1, and two types of manufacturing flow A and manufacturing flow B shown in FIGS. Set and manufactured aggregate.

  The raw materials for producing the recycled coarse aggregate are concrete glass having a manufacturing flow A of 40 to 5 mm and concrete glass having a manufacturing flow B of 40 to 10 mm. The raw materials for producing the recycled fine aggregate are those having a production flow A of 5 mm or less and a production flow B of 10 mm or less.

仕切り版回転数は、回転軸４の回転数を意味する。 2. Outline of Experiment In Experiment 1 and Experiment n, a regenerated coarse aggregate was produced, and in Experiment III and Experiment IV, a regenerated fine aggregate was produced.
The experimental factors and levels are shown in Table-2 below.

The partition plate rotation speed means the rotation speed of the rotary shaft 4.

  In Experiment I, the manufacturing flow was A, and the experimental factors were confirmed at four levels with the number of rotations of the partition plate and the amount of raw material input.

  In Experiment II, the manufacturing flow was A, and the experimental factors were confirmed at six levels with the number of rotations of the partition plate and the amount of raw material input.

  In Experiment III, the production flow was set to A, the raw material input amount was fixed at 25 t / h, and three levels were confirmed with the experimental factor as the number of rotations of the partition plate.

In Experiment IV, the production flow was set to B, the raw material input amount was fixed to 6 t / h, and three levels were confirmed with the experimental factor being the rotation speed of the partition plate. The test items of recycled aggregate are shown in Table 3 below. The quality index of the recycled aggregate was an absolute dry density, a water absorption rate, and a coarse particle rate.

3. Experimental Results Table 4 below shows the variable R (number of rotations of partition plate / raw material input amount), physical properties of recycled aggregates, and correlation coefficients in each experiment.

(1) Absolute dry density FIG. 5 shows the relationship between the variable R (number of rotations of the partition plate / raw material input amount) and the absolute dry density, and its linear regression equation. In all experiments, the absolute value of the correlation coefficient exceeded 0.9, indicating a high correlation. For the recycled coarse aggregate, a high correlation was obtained in the production flow A regardless of whether or not the raw material was specified. For recycled fine aggregate, a high correlation was obtained regardless of the manufacturing flow when the raw material was specified.

(2) Water Absorption Rate FIG. 6 shows the relationship between the variable R (number of rotations of the partition plate / raw material input amount) and the water absorption rate, and its linear regression equation. In all experiments, the absolute value of the correlation coefficient exceeded 0.9, indicating a high correlation. For the recycled coarse aggregate, a high correlation was obtained in the production flow A regardless of whether or not the raw material was specified. For recycled fine aggregate, a high correlation was obtained regardless of the manufacturing flow when the raw material was specified.

(3) Coarse Grain Ratio FIG. 7 shows the relationship between the variable R (number of rotations of the partition plate / raw material input amount) and the coarse grain ratio, and its linear regression equation. In experiments I, II and III, the absolute value of the correlation coefficient was 0.85 to 1, indicating a high correlation.

  For the recycled coarse aggregate, a high correlation was obtained in the production flow A regardless of whether or not the raw material was specified. The recycled fine aggregate had a high correlation (correlation coefficient 11.00) in the production flow A when the raw material was specified.

(4) Summary The above results are summarized below.
1) The recycled coarse aggregate showed a high correlation between the variable R and the quality of the aggregate regardless of whether the raw material was unspecified or specified.
2) Recycled fine aggregate showed a high correlation between variable R and aggregate quality in production flow A when the raw material was specified. Further, in the production flow B, a high correlation was found between the variable R, the absolute dry density, and the water absorption rate.

As described above, the following is possible as the quality control method of the present invention.
1) Regardless of whether or not the raw material of the recycled coarse aggregate is specified, the quality of the recycled aggregate can be controlled by the variable R (number of rotations of the partition plate / raw material input amount). (However, if the raw material is unspecified, the limit is 100t per lot.)
2) The quality of the recycled fine aggregate can be controlled by the variable R in the manufacturing flow A when the raw material is specified.
3) When the raw material is specified, the regenerated fine aggregate can manage the absolute dry density and the water absorption rate by the variable R in the production flow B.
4) The range of variable R for which quality control is possible can be as follows. Recycled coarse aggregate ... 0.67 to 1.88 Recycled fine aggregate ... 1.00 to 4.67 (provided that the quality is absolutely dry density and water absorption)
5) Within the range of the above variable R, it is possible to control (manage) the recycled aggregate quality by performing production twice or more for each type of raw material and deriving a relational expression.
For this reason, the quality control method of this invention can be used as a technique which stabilizes and labor-saving quality control of reproduction | regeneration aggregate manufacture.

It is a vertical side view of the mechanical grinding machine used by the method of this invention. It is a front view of the partition member of the mechanical grinding machine used by the method of this invention. It is explanatory drawing which shows an example of the flow in experiment. It is explanatory drawing which shows an example of the flow in experiment. It is a graph which shows the relationship between the variable R (number of rotations of a partition plate / raw material input amount) and absolute dry density. It is a graph which shows the relationship between the variable R (number of rotations of a partition plate / raw material input amount) and a water absorption rate. It is a graph which shows the relationship between the variable R (number of rotations of a partition plate / raw material input amount) and a coarse grain rate.

DESCRIPTION OF SYMBOLS 1 ... Introduction port 2 ... Discharge port 3 ... Drum body 4 ... Rotating shaft 5 ... Partition member 6 ... Grinding chamber 7 ... Conduction hole 8 ... Grinding material 9 ... Block

Claims (2)

Using a mechanical grime device in which a partition member forming a plurality of grinding chambers is attached to the rotating shaft in the drum body at an angle inclined with respect to the rotating shaft, and a loading material is loaded in the grinding chamber ,
After using 5 to 40 mm of concrete glass as a raw material and treating the raw material with the mechanical grinding machine, the 5 mm or more obtained by the treatment was recovered as recycled coarse aggregate and obtained by the treatment. A method for producing a recycled aggregate for concrete that reprocesses 5 mm or less with the mechanical grinding machine and collects the reprocessed aggregate as a recycled fine aggregate,
The width of the conduction hole formed in the partition member is set to 45 mm when the recycled coarse aggregate is manufactured, and 15 to 30 mm when the recycled fine aggregate is manufactured.
The number of rotations of the partition member (rpm) / the amount of raw material input (t / h) is a variable R. The variable R is 0.67 to 1.88 for the recycled coarse aggregate, and the variable R is 1.00 for the recycled fine aggregate. The manufacturing method of the recycled aggregate for concrete characterized by manufacturing as the range of -4.67. Using a mechanical grime device in which a partition member forming a plurality of grinding chambers is attached to the rotating shaft in the drum body at an angle inclined with respect to the rotating shaft, and a loading material is loaded in the grinding chamber ,
Using 5 to 40 mm concrete glass as a raw material, the raw material is classified into a first small diameter component of 5 to 10 mm and a first large diameter component of 10 to 40 mm, and the first large diameter component is used as the mechanical grinding machine. After processing, the thing of 5 mm or more obtained by the said process is made into a 2nd large diameter component, and the thing of 5 mm or less obtained by the said process is mixed with the 1st small diameter component obtained by the said classification, and 10 mm or less The second small diameter component is reprocessed with the mechanical grinding machine, and the component of 5 mm or more obtained by the reprocessing is mixed with the second large diameter component to regenerate coarse bone. It is a method for producing a recycled aggregate for concrete that is recovered as a material and collects a component of 5 mm or less obtained by the reprocessing as a recycled fine aggregate,
The width of the conduction hole formed in the partition member is set to 45 mm when the recycled coarse aggregate is manufactured, and 15 to 30 mm when the recycled fine aggregate is manufactured.
The number of rotations of the partition member (rpm) / the amount of raw material input (t / h) is a variable R. The variable R is 0.67 to 1.88 for the recycled coarse aggregate, and the variable R is 1.00 for the recycled fine aggregate. The manufacturing method of the recycled aggregate for concrete characterized by manufacturing as the range of -4.67.

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