JP2001261405A - Prepacked concrete construction method using dismantled concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reuse the whole of dismantled concrete. SOLUTION: Dismantled concrete A is fractionated into a block B having a 15 mm or larger particle size and a block C having a particle size smaller than 15 mm by using a screen and the block C, which can not be directly used in a prepacked concrete construction method, is crushed into fine aggregate D for mortar having a 2.5 mm or smaller particle size by using a crusher. The block B is bedded inside a formwork 1 and the mortar prepared by kneading the aggregate D, sand, cement and water is injected from a mortar injecting pipe 2 into the formwork 1 to construct prepacked concrete. The whole of dismantled concrete can be reused by using the block C, which is scrapped usually, as the aggregate D as described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepacked concrete construction method using demolition concrete, and more particularly to a prepacked concrete construction method capable of reusing the entire amount of demolition concrete.

[0002]

2. Description of the Related Art As a method of treating demolition concrete generated when a concrete structure is dismantled, a method of reusing demolition concrete in which demolition concrete is mixed with mortar to construct a foundation for a new building (Japanese Patent Publication No. Hei 5 (1993)). −
No. 34455) has been proposed.

[0003] When constructing a foundation by the method of recycling demolition concrete, first, a foundation is excavated, and a concrete foundation is constructed by a prepacked concrete method in which demolition concrete is poured into the foundation and mortar is injected. Alternatively, a concrete foundation is constructed by a post-packed concrete method in which mortar is poured into the foundation ground and demolition concrete is put into the mortar and compacted.

[0004]

The conventional processing method by reusing demolition concrete aims at cost reduction by eliminating the labor of separating demolition concrete according to the diameter. Is used as aggregate as it is, so mortar is not filled between these small pieces, voids are generated and the strength is low and uneven, and where strength and quality are not required Limited to the use of

[0005] The Standard Specification for Concrete by the Japan Society of Civil Engineers stipulates that aggregates having a diameter of 15 mm or more are used in the prepacked concrete method in order to prevent the occurrence of voids due to improper filling of mortar. The treatment method cannot satisfy this requirement, and it is not desirable to construct a concrete foundation by the above treatment method.

Therefore, when actually reusing demolition concrete by the prepacked concrete method, small pieces of less than 15 mm are removed from the demolition concrete to remove 15 m.
Only concrete blocks of m or more are used, and small pieces smaller than 15 mm will be discarded. However, depending on the concrete dismantling method, small pieces to be discarded reach as much as 30 to 40% of the entire demolition concrete, and the recycling rate is low. There is a problem.
Then, a technical problem to be solved arises in order to improve the recycling rate of demolition concrete, and an object of the present invention is to solve the above problem.

[0007]

DISCLOSURE OF THE INVENTION The present invention proposes to achieve the above-mentioned object, and comprises the steps of dismantling concrete generated by dismantling a concrete structure, comprising: a block having a particle size of 15 mm or more; And crushing a block of less than 15 mm into fine aggregates of 2.5 mm or less, and laying blocks of 15 mm or more as coarse aggregates of prepacked concrete in a formwork, and 2.5 mm or less Provide a prepacked concrete method using demolition concrete that recycles the entire amount of demolition concrete by filling mortar obtained by kneading fine aggregate, sand, cement, and water into a mold through an injection pipe Things.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart of a process for converting dismantled concrete into aggregate. 1. Demolish concrete structures. 2. The demolition concrete is separated into a block having a diameter of 15 mm or more and a block having a diameter of less than 15 mm by a separation means such as a screen. A block of 3.15 mm or more is used as coarse aggregate of prepacked concrete. Since small blocks smaller than 4.15 mm cannot be used for the prepacked concrete method as they are, they are 2.5 m in a crusher such as a vibration mill capable of adjusting the particle size.
m or less. Concrete pieces and fine powder pulverized to 5.2.5 mm or less are used as fine aggregates of mortar for prepacked concrete.

FIG. 2 and FIG. 3 show an outline of a prepacked concrete method using demolition concrete. The installation and reinforcement (not shown) of the formwork 1 are performed. The mortar injection pipe 2 is built in the mold 1. A block B having a diameter of 15 mm or more in demolition concrete A is spread as a coarse aggregate of prepacked concrete in a formwork 1. A mortar is prepared by kneading fine aggregate D obtained by pulverizing a block C of less than 15 mm into 2.5 mm or less, sand, cement and water. Is injected into the bottom of the mold 1 through the mortar injection pipe 2. After the mortar is filled and the mortar water level rises to the design value, the injection is stopped and the top surface is leveled.

[0010] As described above, a block of 15 mm or more is used as coarse aggregate of prepacked concrete.
Small blocks less than 2.5 mm are crushed to 2.5 mm or less and used as fine aggregate of the injected mortar, so that the entire amount of demolition concrete can be reused.

Since the construction cost when using demolition concrete is higher than the construction cost when using new concrete, the place where the demolition concrete is generated, such as a rebuilding site of a building, is used. It is desirable that the increased cost of recycling be offset with the cost of disposal of demolition concrete.

When the entire amount of demolition concrete cannot be reused at a demolition site, if the demolition concrete is used at another construction site, the entire amount can be treated without disposal. Further, a block of less than 15 mm serving as a surplus may be used as it is as a concrete material without performing pulverization. In this case, as shown in FIG.
m is poured into a base mortar having a composition obtained by removing coarse aggregate from a general concrete composition, and is kneaded with a concrete mixer 3 to prepare a concrete E. The concrete E is used for prepacked concrete. Thin walls, long beams, and the like that cannot be constructed by the construction method can be constructed.

[0013] Recycled concrete is not approved for use as a structural member because its quality is not uniform, and its application is limited. However, it can be applied to the following.

Gravity type retaining wall (one that does not require frost resistance) ・ Concrete filling concrete such as sabo dams ・ Basic concrete such as buried pipes and catch basins ・ Leveling concrete, concrete between floors ・ Concrete blocks (irregular blocks) , Wave-dissipating blocks, etc.)-Replacement concrete (population bedrock)-Secondary concrete products (U-shaped grooves, etc.) Examples of using small blocks of less than 15 mm as they are:-Backfill materials-Roadbed materials-Depending on the diameter Classification and reuse for coarse aggregate and fine aggregate.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope of the present invention, and it goes without saying that the present invention extends to those modifications. is there.

[0016]

As described above, according to the prepacked concrete method using the demolition concrete of the present invention, the demolition concrete is classified according to the diameter, and is classified into 15 mm.
The above blocks were used as coarse aggregate of prepacked concrete, and had to be disposed of 15m in the past.
Since concrete pieces less than m are crushed and used as fine aggregate for injected mortar, the entire amount of demolition concrete can be reused, resulting in reduced use of sand and cement and effective use of resources. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a flowchart of a process of converting demolition concrete to aggregate.

FIG. 2 is a flowchart showing an outline of a prepacked concrete method.

FIG. 3 is an explanatory diagram of a prepacked concrete method using demolition concrete.

FIG. 4 is an explanatory view showing another method of using blocks having a diameter of less than 15 mm in demolition concrete.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Formwork 2 Mortar injection pipe 3 Concrete mixer A Demolition concrete B Coarse aggregate with a diameter of 15 mm or more C Concrete piece with a size of less than 15 mm D Fine aggregate with a size of 2.5 mm or less E Recycled concrete

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidemasa Saka 2-1 Tsukudocho, Shinjuku-ku, Tokyo Kumagaya Gumi Tokyo Head Office (72) Inventor Takeharu Yoshimura 2-1 Tsukudocho, Shinjuku-ku, Tokyo Stock Company Kumagai Gumi Tokyo head office F term (reference) 4G012 PA30 PE04 4G055 AA01 AB00 AC00 CA01

Claims (1)

[Claims] 1. Demolition concrete generated by demolishing a concrete structure is separated into blocks having a particle size of 15 mm or more and blocks having a particle size of less than 15 mm.
1. A block of less than 2.5 mm is crushed with a crusher to produce fine aggregate of 2.5 mm or less, and a block of 15 mm or more is laid in a form as coarse aggregate of prepacked concrete.
A prepacked concrete method using demolition concrete in which the entire amount of demolition concrete is reused by filling mortar obtained by kneading fine aggregate, sand, cement, and water crushed to 5 mm or less through an injection pipe.