JP3002909B2 - Recycled coarse aggregate and method for producing recycled coarse aggregate - Google Patents

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 effectively utilizing concrete waste generated by demolition of concrete in a nuclear-related facility and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Peaceful use of nuclear energy in Japan has been in use for more than thirty years, and is now receiving worldwide attention. And there is nuclear power as one of the peaceful uses of nuclear power,
Today, nuclear power plays an important role as a stable power supply. By the way, just as every object has a life, a nuclear power plant cannot avoid its life. If this is a normal facility, the treatment after dismantling of the facility will not be so problematic, but the disposal and dismantling of the dismantled waste from the facilities at the nuclear power plant will need to be studied in the future, including economics.

[0003] It is estimated that hundreds of thousands of tons of waste are generated when dismantling nuclear power plant facilities. At present, disposal of large amounts of waste to general disposal sites is considered to be a problem in the future due to the location of general industrial waste disposal sites. Is economically problematic, and it is required to reuse demolition waste.

[0004]

DISCLOSURE OF THE INVENTION By the way, of the hundreds of thousands of tons of waste generated by dismantling nuclear power plant facilities, 90%
The remainder is believed to be concrete and reinforced waste.
Moreover, it is estimated that most of the concrete has a low radioactivity level of less than 10 ^-4 curie / ton. It is considered that such low-level waste does not need to be carried into the radioactive waste disposal site, but a more rational disposal method is expected.

[0005] In Japan, the basic policy of the country is to dismantle the facilities of a nuclear power plant that has reached the end of its life and use the site. That is, dismantling the facilities of a nuclear power plant does not mean that nuclear power is unnecessary, but it is necessary to construct a new nuclear power plant along with the dismantling. The construction of this nuclear power plant requires a large amount of concrete materials. Also, construction of radioactive waste disposal sites requires a large amount of concrete materials.

[0006] Therefore, if concrete waste generated by demolition of concrete at nuclear facilities can be effectively used for construction of a new nuclear power plant or construction of a radioactive waste disposal site, waste of resources can be eliminated.
In addition, the present invention has been revealed that the disposal with higher safety can be performed, and the cost of dismantling processing is reduced, thereby completing the present invention.

[0007] That is, an object of the present invention is to provide a technique for effectively utilizing waste concrete generated by demolition of concrete in a nuclear-related facility and reducing the processing cost. The object of the present invention is attained by a recycled coarse aggregate characterized in that fine powder is bound via a binder to a crushed material of concrete waste generated by demolition of concrete at a nuclear-related facility.

In addition, a crushing step for crushing concrete waste generated by concrete demolition at a nuclear-related facility, a binder supply step for supplying a binder to the crushed material obtained in the crushing step, and a crushed material obtained in the crushing step are performed. And a fine powder supply step of supplying a fine powder. That is,
According to the present invention, concrete waste generated by the demolition of concrete of nuclear-related facilities can be used as aggregates of concrete materials used for construction of nuclear-related facilities to be newly constructed and construction of radioactive waste disposal sites,
Also, it can be used as a filler to be placed between the radioactive waste disposal containers brought into the radioactive waste disposal site, and this recycled aggregate will be used in places where measures against radiation have been taken. However, even if the recycled aggregate has a low level of radioactivity, there is no problem, and no special disposal as radioactive waste is required, and the processing cost is reduced accordingly.

The present invention will be described in more detail. Although various things are generated as waste from nuclear facilities, aggregate can be regenerated from concrete waste generated by demolition of concrete at nuclear facilities. In order to obtain aggregate from waste concrete generated by demolition of concrete at nuclear facilities, coarse splitting is performed as a first step using a hydraulic breaker, etc.
Crushing is performed to about 500 mm square. After that, as a second step, the earth and sand adhered to the concrete block is removed by grizzly, and in the third step, the concrete block is divided into small pieces by a jaw crusher or the like, and the reinforcing steel and the concrete are separated. In the next fourth step, the rebar separated by the magnetic separator is removed. After the rebar is removed by the magnetic separator, the primary crushing by an impact crusher is performed as a fifth step. That is, the concrete lump conveyed by the belt conveyor is crushed by an impact crusher, and the particles of about 0 to 10 mm are screened.
The particles are separated into particles of about 40 mm and particles of 40 mm or more, and the particles of 40 mm or more are returned to the impact crusher again to obtain particles of 0 to 10 mm and particles of 10 to 40 mm. As a sixth step, the grains having a size of about 10 to 40 mm obtained in the primary crushing step are sent to a coarse aggregate regenerating machine where they are processed and sieved with a screen to obtain a regenerated coarse aggregate. As a seventh step, the granules of about 0 to 10 mm obtained in the primary crushing step are sent to a fine aggregate regenerating machine, processed and sieved by a screen, and the regenerated fine aggregate, fine sand, fine powder ( Sludge) is obtained.

[0010] By the way, it is conceivable to use the crushed concrete waste material generated by demolition of concrete at a nuclear-related facility as recycled aggregate (regenerated coarse aggregate) as it is. It has too many corners and is difficult to use as a coarse aggregate. From such a viewpoint, by binding fine powder to a crushed material via a binder, a shape more preferable as a coarse aggregate can be obtained.

As fine powder, ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, moderately heated Portland cement, sulfate-resistant Portland cement, blast furnace cement, silica cement, fly ash cement, Cement or the like in which calcium is substantially absent is used, but most preferred is a cement in which calcium hydroxide is substantially absent in the solidified product.

It is also possible to use, as the fine powder, sludge generated at the time of crushing concrete waste generated by demolition of concrete at a nuclear-related facility.
Water or water glass can be used as the binder. That is, when cement is used as the fine powder, the function as a binder is exhibited only with water. When sludge generated during the crushing of concrete waste material generated by concrete demolition at a nuclear facility is used as fine powder, water glass or the like is used as a binder.

When the recycled aggregate is supplied onto the inclined rotating plate and a binder such as water is supplied, the recycled aggregate becomes wet, and fine powder such as cement is supplied to the aggregate. Then, the cement adheres to the regenerated aggregate, the shape of the regenerated aggregate is corrected, and the regenerated aggregate has a desired shape, which is extremely excellent as a coarse aggregate.

[0014]

[Example] In order to obtain coarse aggregate from concrete waste generated by dismantling a building instead of dismantling concrete at a nuclear-related facility, coarse cracking is performed as a first step using a hydraulic breaker, etc., and crushing is performed to about 500 mm square. Will be Thereafter, as a second step, the earth and sand attached to the concrete block is removed by grizzly, and in the third step, the concrete block is divided into small pieces by a jaw crusher or the like, and the reinforcing steel and the concrete are separated.

In the next fourth step, the rebar separated by the magnetic separator is removed. After the rebar is removed by the magnetic separator, primary crushing by an impact crusher is performed as a fifth step. In other words, the concrete mass conveyed by the belt conveyor is crushed by the impact crusher,
And about 0-10mm grain on screen, 10-40
mm and 40 mm or more,
mm or more grains are returned to the impact crusher again,
Grains of 0-10 mm and 10-40 mm are obtained.

[0016] 10 to 40 m obtained in the primary crushing step
As a sixth stage, the m-sized grains are sent to a coarse aggregate regenerating machine where they are processed and sieved with a screen to obtain recycled coarse aggregate. As a seventh step, the grains of about 0 to 10 mm obtained in the primary crushing step are sent to a fine aggregate regenerating machine where they are processed and sieved with a screen, and the recycled fine aggregate, fine sand, fine powder ( Sludge) is obtained.

Water is supplied to the regenerated coarse aggregate obtained as described above, and cement in which calcium hydroxide is substantially absent in the solidified cement is supplied. The regenerated coarse aggregate was corrected to a shape having sharp corners, and a regenerated coarse aggregate having a good shape was obtained.

[0018]

According to the present invention, concrete waste generated by concrete demolition of nuclear facilities can be used as coarse aggregate of concrete materials used in the construction of new nuclear facilities and the construction of radioactive waste disposal sites. Also, it can be used as a filler disposed between radioactive waste disposal containers carried into a radioactive waste disposal site, and this recycled coarse aggregate is used in places where measures against radiation are taken. Therefore, even if this recycled coarse aggregate has a low level of radioactivity, there is no problem, and no special disposal is required as radioactive waste, and the disposal cost is correspondingly low. Becomes

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoaki Koyanagi 2-1-1, Tsukimi-cho, Kumagaya-shi, Saitama Chichibu-Cement Co., Ltd. Central Research Laboratory (72) Inventor Hiroaki Kato Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 8 Toshiba Corporation Yokohama Office (72) Inventor Masato Oura 3-1-1 Sachimachi, Hitachi-shi, Ibaraki Hitachi, Ltd. Hitachi, Ltd. Hitachi Plant (58) Field surveyed (Int. Cl. ⁷ , DB name) G21F 9/30 G21F 9/34 G21F 9/36

Claims (2)

(57) [Claims] A recycled coarse aggregate obtained by binding fine powder to a crushed material of concrete waste generated by concrete demolition at a nuclear-related facility via a binder. 2. A crushing step for crushing concrete waste generated by concrete demolition of nuclear facilities,
Production of recycled coarse aggregate, comprising: a binder supply step of supplying a binder to the crushed material obtained in the crushing step; and a fine powder supply step of supplying a fine powder to the crushed material obtained in the crushing step. Method.