JP2010163336A - Method for producing recycled fine aggregate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing recycled fine aggregate that can attain environmental load reduction and energy load reduction in the production thereof and quality improvement of the fine recycled aggregate in the mechanical treatment where the raw material, concrete debris is subjected to crushing and grinding. <P>SOLUTION: (1) The raw material (concrete debris) is classified with a 10 mm sieve into particles of 10-40 mm and particles of 5-10 mm (material 1). (2) The particles of 10-40 mm are fed to a mechanical grinder and are separated into particles of 5 mm or larger and particles of 5 mm or smaller (material 2). (3) The material 1 and the material 2 are mixed and fed again to the mechanical grinder to obtain the recycled fine aggregate of 5 mm or smaller (fine powder of 1 mm or smaller is removed). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a recycled fine aggregate from a concrete block generated when a concrete structure is dismantled.

  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.

At present, in order to obtain recycled aggregates from concrete crumbs obtained after easily crushing demolition concrete blocks, mechanical processing is performed by crushing and grinding with a grinder or cage-type grinding device. Patent Documents 1 to 3 are examples of performing mechanical processing to add crushing and grinding.
Japanese Patent No. 3261125 JP 2006-205118 A JP 2008-104910 A

  These are, as shown in FIG. 1, a drum body 3 provided with an inlet 1 for taking in the ground material at one end and a discharge port 2 for discharging the ground material after grinding at the other end, A rotating shaft 4 penetrating the drum body 3 in the axial length direction of the drum body 3, and attached to the rotating shaft 4 at an angle inclined with respect to the rotating shaft 4, partitioning the inside of the drum body 3 and separating the drum body 3 includes a partition member 5 forming a plurality of grinding chambers 6 communicating with each other, and a grinding loading material 8 which is a required number of metal balls loaded in the grinding chamber 6. The loading material 8 for grinding repeatedly rises and falls as the partition member 5 rotates, and reciprocates in the axial direction of the rotary shaft 4.

  In Patent Document 2, although illustration 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 8 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, and the work efficiency can be improved and the equipment cost can be reduced.

  In Patent Document 3, in order to facilitate the bit replacement work in Patent Document 2, a plurality of cut portions are formed at intervals along the outer peripheral edge, and a U-shaped block 9 is formed with respect to the cut portions. Are fitted.

On the other hand, as a manufacturing method for improving the quality of recycled fine aggregate, there is a method such as heating concrete rags that are raw materials in advance to weaken the adhesion mortar as shown in Patent Document 4 below.
JP 2003-26459 A

  This patent document 4 is 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. And the said heat processing is performed with respect to the concrete crushed material of 5 mm or more by the maximum dimension.

Further, as a processing method using less energy, there is a cage-type grinding apparatus as shown in Patent Document 5 below.
JP 2006-16277 A

  This patent document 5 grinds cement concrete concrete using a cage-type grinding device having a casing, a disk rotating in the casing, and a plurality of ceramic pins concentrically provided on the disk. Thus, recycled fine aggregate is produced.

  The cage-type grinding device is configured, for example, by forming a bowl-shaped (ie, cage-type) rotor by arranging a large number of pins along a circumference of a disk provided in a cylindrical casing.

  By rotating such a rotor, the crushed concrete granule (abraded material) collides with the pin or the casing, and the crushed concrete granule is ground using the impact force.

There are various manufacturing flows including the following Patent Document 6.
JP 2004-238274 A

  This Patent Document 6 discloses a crushing device that supplies a raw material made of concrete waste material to a first sieving device and sifts, and crushes the sieved components having a predetermined particle size or less by an impact grinding action between the particles. The crushed components are classified by a classifier and the fine particles are collected by a dust collector, and the remaining crushed material is collected as reclaimed sand. A component having a predetermined particle size range obtained by sieving by supplying to a second sieving apparatus is supplied to a polishing apparatus that performs polishing by grinding action utilizing the intermingling of the particles and polishing. It is collected as recycled aggregate.

  Patent Document 6 uses a sieve, a crusher, and a polishing device, and uses a crushing action such as a compression crusher such as a jaw crusher and an impeller breaker (trade name: manufactured by Kawasaki Heavy Industries, Ltd.) as the crusher. It is said that a crusher used as a grinding sandmaking machine such as a crusher for crushing and a super sander (trade name: manufactured by Kawasaki Heavy Industries, Ltd.) is preferably used.

  As a polishing apparatus, a polishing apparatus that performs polishing by a grinding action that uses the meshing of particles, for example, a drum reclaimer (trade name: manufactured by Kawasaki Heavy Industries, Ltd.) or a SK polishing machine (trade name: Sera Tech Co., Ltd.). Are preferably used.

  The Ministry of Economy, Trade and Industry established JIS (Japanese Industrial Standard) for “recycled aggregate H for concrete” on March 20, 2005, in order to promote the recycling of 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.

  In the above-mentioned Patent Literatures 1 to 3, among the obtained recycled aggregates, as for the recycled coarse aggregate having a particle size of 5 mm or more, a high quality that satisfies the standard of JIS A5021 can be obtained relatively easily. The regenerated fine aggregate having a particle size of 5 mm or less obtained at that time is difficult to satisfy the standard of JIS A5021. (Note that the concrete trash here refers to a piece of concrete that has been easily crushed to a particle size of about 40 mm or less by a crusher at a demolition site or an intermediate treatment facility.)

  As for the recycled fine aggregate, it is difficult to improve the quality only by the mechanical treatment of crushing and grinding the concrete glass as the raw material, and there has been a problem in the manufacturing method.

  In Patent Document 4, it is necessary to add a relatively large amount of energy of heating to the raw material.

  In other words, as a subject of a manufacturing method that can improve the quality of recycled fine aggregate (recycled aggregate that satisfies the density and water absorption rate among the values specified in JIS A5021), a lot of energy such as heating for pretreatment Is necessary, and the installation and maintenance of heating equipment is costly.

  In addition, the quality of recycled fine aggregates is affected by the quality of the raw aggregate in the demolished concrete that is the raw material. It was considered difficult.

  Patent Document 5 does not consider the quality of the raw aggregate in the demolished concrete, and does not show the particle size of the input raw material.

  Patent Document 6 does not consider the quality of the raw aggregate in the demolished concrete.

  The object of the present invention is to eliminate the inconveniences of the conventional examples described above, and when adopting a mechanical treatment method that crushes and grinds the raw contegal, it reduces the environmental load during the production of recycled aggregates and reduces the energy load. An object of the present invention is to provide a method for producing a regenerated fine aggregate that can realize reduction and improve the quality of the regenerated fine aggregate.

  In order to achieve the above object, the present invention (1) classifies the raw material (concrete glass) with a 10 mm sieve, divides it into 10 to 40 mm and 5 to 10 mm (material 1), and (2) 10 to 40 mm in the drum body. A partition member for forming a plurality of grinding chambers is provided on the rotating shaft, and a charging material is put into a mechanical grinding machine loaded in the grinding chamber, and divided into 5 mm or more and 5 mm or less (material 2), (3) The material 1 and the material 2 are mixed, and again put into the mechanical grinding machine, and the obtained 5 mm or less (excluding fine powder of 1 mm or less) is used as a recycled fine aggregate, and the mechanical grinding machine The gist is that a partition member for forming a plurality of grinding chambers is provided on a rotating shaft in the drum body, and a loading material is loaded into the grinding chamber.

  According to the first and second aspects of the present invention, by focusing on the particle size range of the input raw material, and by including the raw coarse aggregate having a higher quality than the raw fine aggregate in the input raw material, In order to improve, the particle diameter range of the input raw material was set to 10 mm or less. Compared to the case where the particle size range of the input material is 5 mm or less, the quality of the regenerated fine aggregate is improved when the particle size range of the input material is 10 mm or less.

As described above, according to the method for producing a recycled fine aggregate of the present invention, the following becomes possible.
(1) Compared to the case where the particle size range of the input material is 5 mm or less, the quality (absolute dry density / water absorption) of the recycled fine aggregate is improved when the particle size range of the input material is 10 mm or less. can do.
(2) The absolute dry density and water absorption rate of the regenerated fine aggregate can satisfy the JIS standard value (JIS A5021) of the high-quality regenerated aggregate (regenerated aggregate H).
For this reason, this manufacturing method can be used as a technique for improving the quality of recycled fine aggregate.

  Hereinafter, embodiments of the present invention will be described in detail. The present invention uses a mechanical grime apparatus as shown in FIG. 1 described in the above-described conventional example as a mechanical treatment for 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. These loaded materials 8 fall after being strongly bounced up by colliding with two inclined partition members 5, are repeatedly dropped and dropped, and are quickly moved in the axial direction of the rotary shaft 4. Thus, the collision between the material to be ground and the load 8 for grinding is performed uniformly and vigorously, and the grinding process is efficiently performed in the second grinding chamber 6, and the particles of the ground material are ground. The diameter becomes even 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%.

  The present invention aims to reduce the environmental burden, and focuses on reducing the energy load during the production of recycled aggregates. The idea is to improve quality.

  Coarse aggregates and fine aggregates used in concrete are divided by a particle size of 5 mm. In the conventional method for producing recycled fine aggregate, the particle size range of the input raw material has been set to 5 mm or less in consideration of this. However, when the quality of the raw fine aggregate in the demolished concrete is not high, it is difficult to improve the quality of the recycled fine aggregate to be manufactured.

  Therefore, attention was paid to the particle size range of the input raw material. That is, the quality of raw materials is improved by including raw coarse aggregates with higher quality than the raw fine aggregates in the input raw material. Here, the particle size range of the input raw materials is set to 10 mm or less.

FIG. 4 shows the manufacturing flow of the present invention.
(1) The raw material (concrete glass) is classified with a 10 mm sieve and divided into 10 to 40 mm and 5 to 10 mm (Material 1).
(2) 10 to 40 mm is placed in a mechanical surfacing device provided with a partition member that forms a plurality of grinding chambers on the rotating shaft in the drum body, and the loading material is loaded in the grinding chamber. (Material 2)
(3) The material 1 and the material 2 are mixed and again put into a mechanical grinding machine, and the obtained 5 mm or less (excluding fine powder of 1 mm or less) is used as a recycled fine aggregate.

  The production method of the present invention requires that the quality of the regenerated fine aggregate is lower when the particle size range of the input raw material is 10 mm or less than when the particle size range of the input raw material is 5 mm or less. It is to improve.

As a quality index of recycled fine aggregate, the absolute dry density and water absorption rate indicating the basic physical properties of aggregate are listed. Here, according to JISA5021, which is a JIS standard for high-quality recycled aggregate (recycled aggregate H), the following is an indicator.
(1) Absolutely dry density 2.5 g / cm 3 or more (2.45 g / cm 3 or more)
(2) Water absorption rate 3.5% or less

Examples will be described below.
1. Experimental Design (1) Material Properties Table 1 below shows the physical properties of raw aggregates taken from a specific building (here, referred to as Building A) treated with hydrochloric acid.

  In both Experiment I and Experiment II, the demolished concrete obtained from Building A was used as a raw material. As a comparison, examples of past production of recycled aggregates are also shown.

  For Experiment III, it was assumed that it was generally available at the intermediate treatment plant, and concrete debris with an unspecified demolished building was used as a raw material.

  The raw coarse aggregate used in Experiment I and Experiment II was crushed stone, but its quality (absolute dry density, 1 water absorption) was equivalent to that of the comparative example of river gravel. 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.

(2) Recycled fine aggregate production method Recycled aggregate production was performed using the mechanical grinding machine shown in FIG. 1, and two types of production flow shown in FIGS. 3 and 4 were set and examined.

  Manufacturing flow A is a conventional method, the raw material when manufacturing recycled fine aggregate is 5 mm or less, and manufacturing flow B is the manufacturing flow of the present invention which is the subject of this time, and manufactured recycled fine aggregate The raw material at the time of doing is a thing of 10 mm or less.

  In Experiment I and Experiment II, the raw concrete obtained from the dismantling of Building A was crushed in an intermediate treatment plant, classified into 40 to 5 mm, and coarse aggregate was produced using this as a raw material. Manufactured with the raw materials containing.

  In Experiment III, only a fine aggregate was produced using a concrete glass of 10 mm or less as a raw material.

2. Outline of experiment Table 2 shows the experimental factors and levels. Absolute dry density and water absorption were compared as quality indicators of recycled fine aggregates.

In Experiment I, the manufacturing flow was set to A, the processing speed when manufacturing recycled fine aggregate was fixed at 25 t / h, which has been proven in the past, and the experimental factor was confirmed at three levels with the number of rotations of the partition plate .
In Experiment II, the manufacturing flow was set to B, the processing speed was fixed at 6 t / h, and three levels were confirmed with the experimental factor being the rotation speed of the partition plate. In Experiment III, the manufacturing flow was set to B and the partition plate was rotated. The number was fixed at 28 revolutions / minute, and two levels were confirmed with the experimental factor as the processing speed.

3. Experimental Results (1) Absolute Dry Density FIG. 5 shows the relationship between the rotational speed of the partition plate and the absolute dry density of the recycled fine aggregate in each experiment. In both Experiment I and Experiment II, the absolute dry density increased as the number of rotations of the partition plate increased. When A2, B3, and C2 having the same rotational speed were compared, A2 <B3 <C2, and C2 showed a value of 2.45 g / cm 3 or more, and was of high quality.

(2) Water Absorption Rate FIG. 6 shows the relationship between the number of rotations of the partition plate and the water absorption rate of the recycled fine aggregate in each experiment. In both Experiment I and Experiment II, the water absorption decreased as the number of rotations of the partition plate increased. When A2, B3, and C2 having the same rotational speed were compared, A2>B3> C2 was obtained, and C2 showed a value of 3.5% or less, which was high quality.

  From the above, regardless of the production flow, the increase in the number of rotations of the partition plate increases the absolute dry density and decreases the water absorption rate, and the production flow B has a higher quality in the absolute dry density and water absorption rate than the production flow A. Regenerated fine aggregate was obtained. In addition, in the production flow B, a regenerated fine aggregate satisfying the JIS standard value (JIS A021) of the high quality reclaimed aggregate (regenerated aggregate H) was obtained.

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 a flowchart of a prior art example. It is a flowchart which shows one Embodiment of this invention. It is a graph which shows the relationship between the rotation speed of a partition plate, and the absolute dry density of reproduction | regeneration fine aggregate. It is a graph which shows the relationship between the rotation speed of a partition plate, and the water absorption rate of a reproduction | regeneration fine aggregate.

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)

(1) The raw material (concrete glass) is classified with a 10 mm sieve and divided into 10 to 40 mm and 5 to 10 mm (material 1).
(2) 10 to 40 mm is placed in a mechanical surfacing device provided with a partition member that forms a plurality of grinding chambers on the rotating shaft in the drum body, and the loading material is loaded in the grinding chamber. (Material 2)
(3) The material 1 and the material 2 are mixed and again put into a mechanical grinding machine, and the obtained 5 mm or less (excluding fine powder of 1 mm or less) is used as a recycled fine aggregate. A method for producing recycled fine aggregate.   2. The method for producing a recycled fine aggregate according to claim 1, wherein the mechanical grinding device is provided with a partition member that forms a plurality of grinding chambers on a rotating shaft in the drum body, and the loading material is loaded into the grinding chamber. .

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