JPH04359194A - Reclaimed coarse aggregate and manufacture thereof - Google Patents

Abstract

PURPOSE:To effectively utilize wastes and reduce the disposal cost by binding fine powder to a crushed material of concrete wastes generated when the concrete of a nuclear power-related facility is demolished via a binder. CONSTITUTION:Concrete is coarsely cracked to about 500mm square by a hydraulic breaker, then the sediment stuck to concrete lumps is removed with a grizzly. The concrete lumps are finely cracked with a jaw crusher to separate reinforcing bars and concrete, and separated reinforcing bars are removed with a magnetic separator. After the removal, the concrete is crushed with a impact crusher to obtain grains with the grain size 0-10mm and 10-40mm. Grains with the grain size 10-40mm are processed with a coarse aggregate reclaimer to obtain reclaimed coarse aggregates. Grains with the grain size 0-10mm are processed with a fine aggregate reclaimer and sifted into reclaimed fine aggregates, fine sand and fine powder. Fine powder cement practically containing no calcium hydroxide is added to the reclaimed coarse aggregates with water used as a binder, and rounded and well-shaped reclaimed coarse aggregates are obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycled coarse aggregate that effectively utilizes concrete waste generated from the demolition of concrete at nuclear power related facilities, and a method for producing the same.

0002

[Background of the Invention] The peaceful use of nuclear energy has been in use in Japan for more than 30 years, and today it is attracting worldwide attention. Nuclear power generation is one of the peaceful uses of nuclear energy.
Today, nuclear power generation plays a major role as a stable source of electricity supply. By the way, just as all things have a lifespan, nuclear power plants cannot avoid their lifespan. If this is a normal facility, there would not be much of a problem with how to dispose of it after dismantling the facility, but the treatment and disposal of dismantled waste from nuclear power plant facilities will need to be considered in the future, including economic considerations.

[0003] Furthermore, it is estimated that hundreds of thousands of tons of waste will be generated when nuclear power plant facilities are dismantled. Currently, disposing of a large amount of waste at a general industrial waste disposal site may become a problem in the future due to location issues at the general industrial waste disposal site, but disposing of it at a radioactive waste disposal site is However, there is a problem from an economic point of view, and there is a need to reuse demolition waste.

0004

[Disclosure of the invention] By the way, 90% of the hundreds of thousands of tons of waste generated by dismantling nuclear power plant facilities
The remainder is believed to be concrete and rebar scrap. Moreover, it is estimated that most of the concrete has a low radioactivity level of less than 10-4 curies/ton. Although it is thought that such low-level waste does not need to be transported to a radioactive waste disposal site, a more rational disposal method is expected.

[0005] Furthermore, in Japan, the basic policy of the country is to dismantle nuclear power plant facilities that have reached the end of their service life and to utilize the sites. In other words, the dismantling of nuclear power plant facilities does not mean that nuclear power generation is no longer necessary; instead, a new nuclear power plant will need to be constructed in conjunction with the dismantling. Construction of this nuclear power plant requires large amounts of concrete materials. Furthermore, construction of radioactive waste disposal sites also requires large amounts of concrete materials.

[0006] Therefore, if concrete waste generated from the concrete demolition of nuclear power related facilities can be effectively used in the construction of new nuclear power plants and radioactive waste disposal sites, it will be possible to eliminate wasteful use of resources.
Furthermore, it was discovered that disposal could be carried out with higher safety, and the dismantling costs would be lower, leading to the completion of the present invention.

[0007] That is, an object of the present invention is to provide a technique for effectively utilizing concrete waste generated from concrete demolition of nuclear power related facilities and reducing processing costs. This object of the present invention is achieved by a recycled coarse aggregate characterized in that fine powder is bound to crushed concrete waste material generated by concrete demolition of nuclear power related facilities via a binder.

[0008] Furthermore, there is a crushing process for crushing concrete waste generated from concrete demolition of nuclear power related facilities, a binder supply process for supplying a binder to the crushed materials obtained in the crushing process, and a binder supplying process for supplying a binder to the crushed materials obtained in the crushing process. This is achieved by a method for producing recycled coarse aggregate characterized by comprising a fine powder supplying step of supplying fine powder. That is, according to the present invention, concrete waste generated from concrete demolition of nuclear power related facilities can be used as aggregate for concrete materials used in the construction of newly constructed nuclear power related facilities and radioactive waste disposal sites, and , it can be used as a filler between radioactive waste processing containers transported to radioactive waste disposal sites, and this recycled aggregate will be used in areas where measures against radiation have been taken. There is no problem even if this recycled aggregate has a low level of radioactivity, and no special disposal is required as radioactive waste, which reduces processing costs accordingly.

The present invention will be explained in more detail. Nuclear-related facilities generate various waste materials, and aggregate can be regenerated from concrete waste generated from the demolition of concrete from nuclear-related facilities. In order to obtain aggregate from concrete waste generated from the concrete demolition of nuclear power-related facilities, the first step is to roughly break it using a hydraulic breaker, etc.
Crushing is performed to about 500 mm square. After this, in the second step, the earth and sand adhering to the concrete mass is removed by a grizzly bear, and in the third stage, the concrete mass is broken into smaller pieces using a jaw crusher or the like, and the reinforcing bars and concrete are separated. In the next fourth step, the peeled reinforcing bars are removed by a magnetic separator. After removing the reinforcing bars using a magnetic separator, the fifth step is primary crushing using an impact crusher. That is, a concrete block conveyed by a belt conveyor is crushed by an impact crusher, and then crushed by a screen into particles of about 0 to 10 mm, 10 to 10 mm.
Separated into grains of about 40 mm and grains of 40 mm or more,
The grains of 40 mm or more are returned to the impact crusher again to obtain grains of 0 to 10 mm and grains of 10 to 40 mm. The particles of about 10 to 40 mm obtained in the primary crushing step are
In the sixth stage, it is sent to a coarse aggregate regenerator for processing and sifted through a screen to obtain recycled coarse aggregate. The particles of about 0 to 10 mm obtained in the primary crushing step are
As a step, it is sent to a fine aggregate regenerator for processing and sifted through a screen to obtain recycled fine aggregate, fine sand, and fine powder (sludge).

[0010] By the way, it is conceivable that the crushed concrete waste generated from the demolition of concrete in nuclear power related facilities could be used as recycled aggregate (recycled coarse aggregate), but if the crushed material is in its original form, it will not have the same shape. It has too many corners and is difficult to use as a coarse aggregate.From this point of view, by binding fine powder to the crushed material via a binder, it can be made into a more preferable shape as a coarse aggregate.

Fine powders include ordinary Portland cement, early strength Portland cement, ultra early strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, blast furnace cement, silica cement, fly ash cement, and hydroxide in the solidified material. A cement or the like that is substantially free of calcium may be used, but the most preferred is a cement that substantially contains no calcium hydroxide in its solidified material.

[0012] Furthermore, as the fine powder, it is also possible to use sludge produced during the crushing of concrete waste generated from the demolition of concrete at nuclear power related facilities. Water, water glass, etc. can be used as the binder. That is, when cement is used as fine powder, water alone can function as a binder. When the sludge produced during the crushing of concrete waste generated from the demolition of concrete at nuclear power-related facilities is used as a fine powder, water glass or the like is used as a binder.

[0013] When the above-mentioned recycled aggregate is supplied onto the slanted rotary plate and a binder such as water is supplied, the recycled aggregate becomes wet, and fine powder such as cement is supplied to the recycled aggregate. When this happens, the cement sticks to the recycled aggregate, correcting the shape of the recycled aggregate and making it into the desired shape, making it an extremely excellent coarse aggregate.

[0014]

[Example] In order to obtain coarse aggregate from concrete waste generated from demolition of buildings instead of concrete demolition of nuclear power-related facilities, the first step is to roughly break it using a hydraulic breaker, etc., and crush it into approximately 500 mm square pieces. be exposed. After this, in the second stage, the earth and sand attached to the concrete mass is removed by a grizzly bear, and in the third stage, the concrete mass is broken into small pieces using a jaw crusher, etc.
Peeling the reinforcing steel and concrete.

In the next fourth step, the peeled reinforcing bars are removed by a magnetic separator. After removing the reinforcing bars using a magnetic separator, the fifth step is primary crushing using an impact crusher. In other words, a concrete block transported by a belt conveyor is crushed by an impact crusher,
Then, with a screen, particles of about 0 to 10 mm, 10 to 40
Separated into grains of about mm and grains of 40 mm or more,
Particles larger than mm are returned to the impact crusher again,
Obtain grains of 0-10 mm and grains of 10-40 mm.

[0016] The 10 to 40 m obtained in the primary crushing step
In the sixth stage, the grains of about m size are sent to a coarse aggregate regenerator for processing, and are sieved through a screen to obtain recycled coarse aggregate. In the seventh stage, the particles of about 0 to 10 mm obtained in the primary crushing process are sent to a fine aggregate regenerator for processing, and are sieved through a screen to produce recycled fine aggregate, fine sand, and fine powder ( sludge) is obtained.

[0017] Water is supplied to the recycled coarse aggregate obtained as described above, and cement in which substantially no calcium hydroxide is present in the cement solidified body is supplied, and cement is added to the recycled coarse aggregate. The recycled coarse aggregate was modified to have a rounded shape, resulting in a recycled coarse aggregate with a good shape.

[0018]

[Effects] According to the present invention, concrete waste generated from concrete demolition of nuclear power related facilities can be used as coarse aggregate for concrete materials used in the construction of newly constructed nuclear power related facilities and radioactive waste disposal sites. It can also be used as a filler between radioactive waste processing containers delivered to radioactive waste disposal sites, and this recycled coarse aggregate can also be used in areas where measures are taken against radiation. Therefore, there is no problem even if this recycled coarse aggregate has a low level of radioactivity, and there is no need for special disposal as radioactive waste, and the processing cost is accordingly low. becomes.

Claims (2)

[Claims] 1. A recycled coarse aggregate characterized in that fine powder is bound to crushed concrete waste generated from the demolition of concrete at nuclear power related facilities via a binder. Claim 2: A crushing process for crushing concrete waste generated from concrete demolition of nuclear power related facilities, a binder supply process for supplying a binder to the crushed material obtained in the crushing process, and a binder supplying process for supplying a binder to the crushed material obtained in the crushing process. A method for producing recycled coarse aggregate, comprising the step of supplying fine powder.