JPH07316532A - Production of static crushing agent - Google Patents

Abstract

PURPOSE:To provide a method for producing a static crushing agent for avoiding a static crushing agent packing operation in a cast-in place operation and facilitating aftertreatment. CONSTITUTION:A static crushing agent formed in dry powder is continuously granulated into firm almond-like briquette by a briquetting machine under high pressure and then ground into granules having a particle size distribution of 15-20wt.% of granules with 1-2mm particle diameters, 55-60wt.% of granules with 2-4mm particle diameters and 35-20wt.% of granules with 4-5mm particle diameters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a static crushing agent used for treating pile heads of cast-in-place piles.

[0002]

2. Description of the Related Art Generally, as a foundation pile for building a building or a bridge, a so-called place where a pile hole is excavated in the ground at the site and a concrete is placed in the pile hole to form a pile. The pile driving is adopted. In the case of this place driving,
It is necessary to crush and remove the bad concrete in the pile head surplus area. However, the conventional method of crushing using a breaker or the like causes problems such as noise and vibration given to the neighborhood causing deterioration of the environment.

Therefore, as a construction method for solving such a problem, the applicant of the present application has already proposed a pile head treatment method using a static crushing agent (Japanese Patent Application No. 57-201048). This pile head treatment method is, for example, to lay a reinforced basket with an empty spiral sheath pipe attached in the excavated pile hole, and to fill the spiral sheath pipe with a static crushing agent kneaded with water before placing concrete, Hydration expansion of the static crushing agent was attempted along with curing of concrete, and cracks were generated on the planned cutting line of concrete piles to remove defective concrete in the surplus portion.

However, in the above-mentioned conventional pile head treatment method for cast-in-place piles, water was added to the static crushing agent, which was kneaded in advance into a slurry state and then filled in the sheath tube. Although the crushing effect is excellent, it is complicated in terms of work such as measurement of kneading water of the static crushing agent, kneading work, and adjustment of expansion pressure developing time after kneading. In addition, when the pile heads of cast-in-place piles are treated with static crushing agents, only a few mm of cracks can be generated, which is not sufficient for removing the pile head surplus portion. , It takes a long time for post-processing.

[0005]

However, the static crushing agent used in the conventional pile head treatment method for cast-in-place piles requires a troublesome pre-work, and the crack width is about several mm. Since it is insufficient for removing the pile pile surplus portion, it has been desired to produce a static crushing agent which is easier to use and has a larger crack width.

[0006] Therefore, the technical problem in the present invention for solving the above problems is to manufacture a static crushing agent which avoids the complexity of the static crushing agent filling work in the place-casting work and facilitates the post-treatment. To provide a method.

[0007]

A method for producing a static crushing agent according to the present invention is a method in which a crushing agent formed into dry powder is continuously granulated into a strong almond-shaped briquette at a high pressure by a briquetting machine, After that, pulverize to a particle size of 1-2 m
m is 15 to 20% by weight, particle size 2 to 4 mm is 55 to 60% by weight, and particle size 4 to 5 mm is 35 to 20% by weight.

[Specific Structure] The static crushing agent used in the present invention includes calcium alumino ferrite [(CaO) ₄ .Al ₂ O ₃ .Fe ₂ O ₃ ], free calcium oxide (CaO) and oxidation. Magnesium (Mg
O) is a basic component, and borate or the like is added to this as a retarder. Then, the expression time of the hydration expansion pressure can be adjusted by appropriately changing the type and addition amount of the retarder.

The reason why the static crushing agent is formed into a granule is to maintain a space between the particles so that the stabilizing solution can sufficiently wrap the particles. As a result, even if the container filled with the static crushing agent is simply immersed in the stabilizing solution, each granule is sufficiently hydrated and the expansion pressure is developed. The static crushing agent can be formed into granules by continuously granulating the dry powder of the crushing agent into a strong almond-shaped briquette with high pressure using a briquetting machine, or crushing with a compacting machine. Examples include a method in which dry powder of the agent is compression molded into a plate shape with a smooth roll, and then crushed and granulated, and other dry compression molding methods.

The size of the granules of the static crushing agent is shown in Table 1 below.
The particle size distribution of

[0011]

[Table 1]

The method in which the granular static crushing agent filled in the container absorbs water is that the container itself is formed of an impermeable material,
The openings at both ends are covered with a net formed of a mesh that does not allow the granules to fall out, and water is absorbed through the net. The stable liquid absorbed by the static crushing agent is injected into the pile hole to prevent collapse of the peripheral wall of the pile hole during excavation of the pile hole. For example, a bentonite solution or a bentonite solution added with CMC or a dispersant is used. Something is used.

As a means for the static crushing agent to absorb the stabilizing liquid in the pile hole, if the stabilizing liquid is sufficiently filled in the pile hole, the container should be inserted when the rebar cage is inserted into the pile hole. If it is submerged in the stabilizing liquid to absorb water, or if the stabilizing liquid is not sufficiently filled, try to raise the level of the stabilizing liquid when pouring concrete and immerse the container in the stabilizing liquid to make it static. Absorb the water of the crushing agent. The optimum hydration condition of the static crushing agent can be adjusted by adjusting the time of immersion in the stabilizing solution.

[Pile head treatment method using the static crushing agent of the present invention] Next, a method of implementing the pile head treatment method using the static crushing agent of the present invention will be described with reference to FIG. First, a pile hole is excavated in the presence of a stabilizing liquid. Then, the main bar edging material is attached to the rebar cage main bar (step 101). Next, a granular static crushing material is filled into a container, this container is attached to a rebar cage (step 102), and the rebar cage with the container containing the static crushing material is placed in a pile hole filled with a stabilizing solution. Insert into and submerge. When the container is submerged in the stabilizing solution, the stabilizing solution penetrates into the container from the nets on both ends of the container. Water is absorbed (step 103). After that, while replacing the concrete with the stabilizing liquid, the concrete is placed above the crushing planning line (Step 1
04). After the completion of casting, the concrete is cured until the strength of the concrete appears. At the same time, hydration expansion of the statically crushed material is attempted (step 105). After the concrete is cured, the expansion pressure of the static crushing agent is awaited, a crack is generated on the crushing planning line, the surplus concrete portion is removed, and the pile head treatment is finished (step 106).

When the treatment method of the present invention is compared with the conventional method shown in FIG. 2, the static crushing agent water is metered, the crushing agent water is kneaded, and the container preliminarily attached to the rebar cage. The operation of filling the slurry with the slurry (step 107) can be omitted in the case of the present invention.

[0016]

With the above structure, in the method for producing a static crushing agent according to the present invention, the crushing agent formed into dry powder is continuously granulated into a strong almond-shaped briquette by a briquetting machine at a high pressure, and thereafter, By crushing and forming into granules with a prescribed particle size distribution, the basic component and retarder are mixed appropriately in each granule to improve water absorption and hydration reactivity, and static hydration expansion pressure is large. Form a crushing agent.

Further, the static crushing agent has a particle size of 1 to 2 mm of 15
~ 20% by weight, particle size 2-4mm is 55-60% by weight, particle size 4-5mm is 35-20% by weight. And when it is immersed in a highly viscous bentonite solution or a stable solution containing CMC or a dispersant added to a bentonite solution, the highly viscous stable solution wraps each granule sufficiently, and the water in the stable solution is absorbed from the granule surface. Permeate the inside of the granules, let the static crushing agent absorb water and cause a hydration reaction, and after an appropriate time, the hydration expansion pressure will be properly expressed according to the concrete strength development. A crack of about several cm is generated along the line to enable removal of excess concrete.

[0018]

[Examples] CAB (trade name of Sumitomo Cement Co., Ltd.), which is a kind of static crushing agent, was molded into granules, and as shown in FIG.
It was filled in a flat spiral sheath tube 1 (maximum diameter 45 mm, length 50 cm). Then, both ends of the spiral sheath pipe 1 are closed with a net 4, and a plurality of them are arranged along a reinforcing bar cage 3 on the planned cutting line 2 of the cast-in-place concrete pile head (diameter 1 m) and attached with a binding wire. . Next, the rebar cage 3 was inserted into the pile hole, the spiral sheath tube 1 was submerged in the stabilizing solution, and then concrete was poured. And 1
When it was dug up after 0 days, a crack having a width of 1 to 2 cm was found along the planned cutting line 2.

[0019]

As described above, according to the method for producing a static crushing agent according to the present invention, the crushing agent formed in dry powder is continuously and strongly almond-shaped briquette by a briquetting machine at high pressure. Granules were formed into granules and then pulverized to a prescribed particle size distribution, so that the basic component and the retarder are properly blended in each granule, water absorption and hydration reactivity are improved, and hydration expansion pressure is improved. As a result, it is possible to obtain a static crushing agent having a high concrete crushing capacity for treating pile heads of cast-in-place piles.

The static crushing agent has a particle size of 1 to 2 mm of 15
~ 20% by weight, particle size 2-4mm is 55-60% by weight, particle size 4-5mm is 35-20% by weight. And when it is immersed in a highly viscous bentonite solution used in excavation or a stable solution in which CMC or a dispersant is added to a bentonite solution, the highly viscous stable solution sufficiently wraps each granule, Moisture penetrates from the surface of the granules into the granules and can be sufficiently absorbed by the static crushing agent, and the necessary hydration reaction occurs. Can be properly expressed, and a few c along the crushing plan line
A crack of about m can be generated, and the pile head can be broken so that the excess pile concrete can be easily removed.

Therefore, it is possible to omit the kneading water and the kneading work as the pre-work for filling the container with the static crushing agent which has been conventionally required, and to simplify and speed up the pre-work. In addition, it is possible to easily remove the overfilled concrete, and it is possible to realize time reduction and cost reduction in the pile head treatment of cast-in-place piles.

[Brief description of drawings]

FIG. 1 is a flow chart showing working steps of a pile head processing method using a stabilizing solution according to the present invention.

FIG. 2 is a flowchart showing a work process of a conventional example.

FIG. 3 is an explanatory perspective view showing a state in which a spiral sheath tube is attached to a rebar cage.

[Explanation of signs] 1 Spiral sheath tube 2 Planned cutting line 3 Reinforcing cage

Claims (1)

[Claims] 1. A crushing agent formed into dry powder is continuously granulated into a strong almond-shaped briquette at a high pressure by a briquetting machine, and then crushed to a particle size of 1 to 2 m.
A static crushing agent characterized by forming into granules having a particle size distribution in which m is 15 to 20% by weight, particle size 2 to 4 mm is 55 to 60% by weight, and particle size 4 to 5 mm is 35 to 20% by weight. Production method.