JP2690726B2 - Method for producing highly expandable zeolite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a highly expandable zeolite.

[0002]

2. Description of the Related Art In civil engineering and construction work, as backfilling injection material and filling material for gaps such as voids and cavities,
A mixture of cement and gravel, sand, clay, etc., and a foaming agent for physically introducing air bubbles, or a foaming agent for generating gas by a chemical reaction, and quick setting A variety of materials such as those having properties are used. Among them, those to which a foaming agent or a foaming agent has been added are excellent in flowability, pumpability, material separability, economical efficiency, etc.

This foaming agent is one which physically introduces air bubbles during the kneading of materials by a surface active action.
The main components are anionic surfactants, nonionic surfactants, protein derivatives such as gelatin and casein, and alkyl sulfonates. However,
These foaming agents have different foaming conditions depending on the amount of addition and the kneading conditions such as the size of the mixer, the shape of the blades, the number of rotations of the blades, and the stirring time. It is difficult to keep it constant at all times, and it is difficult to obtain uniform bubbles because the bubbles are physically introduced during the material kneading, and there are variations in the size of the bubbles, which causes large bubbles in the upper layer of the packing material. However, there is a drawback in that the volume is reduced and cavities are easily formed, which makes it difficult to close the cells.

On the other hand, as the foaming agent, in addition to aluminum powder, a two-component system of hydrogen peroxide-calcium hypochlorite, hydrochloric acid-sodium bicarbonate, etc. is typically used. However, aluminum powder is generally used for mortar for prepacked concrete, grout for prestressed concrete, aerated concrete, etc., and although the amount used is only about 0.01% with respect to the cement weight, it is used as a gap filler. When using aluminum powder, several times to several tens of times the amount used for the above application is required, and when the addition amount of aluminum powder increases, foaming begins to occur rapidly from a certain time and it is extremely difficult to control the foaming amount. The heat generated by foaming shortens the curing time of the filling material itself,
Due to a sudden increase in foaming pressure, it causes unexpected damage to a construction frame such as a tunnel frame, a uniform foamed solidified body cannot be obtained, and the foaming agent generates hydrogen gas. Since the powder generates hydrogen gas by reacting with alkali, it is difficult to handle for safety, such as the danger of explosion of hydrogen gas with a low explosion limit, and metal alkali is a dangerous material that may cause a fire. It has a drawback that workability is poor.

Therefore, there is a strong demand for the development of a foamable material that is free from such a defect and that is capable of foaming a safe gas and that foaming does not suddenly occur in a short time.

[0006]

SUMMARY OF THE INVENTION Under the above circumstances, the present invention aims to provide a foamable material in which foaming gas is safe, foaming is performed relatively slowly, and the foaming amount is large. It was made as.

[0007]

The inventors of the present invention have conducted various studies to develop a foamable material having the above-mentioned preferable characteristics, and as a result, zeolite was calcined to a predetermined temperature and dried in a dry air at a predetermined temperature or lower. Based on this finding, the inventors of the present invention have completed the present invention based on this finding that a substance that is forcibly cooled to 2) generates a remarkably large amount of bubbles relatively slowly when water is added, and functions as an extremely excellent foaming agent.

That is, the present invention uses 100% zeolite.
The present invention provides a method for producing a highly expandable zeolite, which comprises calcination at ˜700 ° C. and then forcibly cooling to a low temperature of 10 ° C. or less in dry air.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the highly expandable zeolite is a zeolite at 100 to 700 ° C., preferably 4
It can be obtained by firing at 00 to 600 ° C. and then forcibly cooling it to a low temperature of 10 ° C. or less in dry air. At this time, the forced cooling may be performed after firing, after allowing to cool, or after gradually cooling to room temperature, or after allowing to cool and then further cooling to room temperature. The zeolite used as the raw material may be either natural zeolite or synthetic zeolite, but natural zeolite is preferred. Zeolite is usually used after being pulverized and classified to have a predetermined particle size. The amount of foaming increases remarkably by forced cooling. For example, FIG. 1 shows 50
It is a graph showing the relationship between the forced cooling temperature and the foaming amount of zeolite calcined at 0 ° C. From this, it can be seen that the lower the forced cooling temperature, the larger the foaming amount. In this way, the foaming amount can be adjusted by changing the forced cooling temperature. The forced cooling is performed by a conventional method, for example, a method of holding in a freezer warehouse under a predetermined condition, for example, a predetermined temperature for a predetermined time.

Zeolite has a crystal structure in which tetrahedra of silicate SiO ₂ are polymerized, and a foaming gas such as nitrogen or water is usually taken into the space inside the crystal. It is presumed that it will be replaced by nitrogen and the like in the air by firing at an appropriate temperature. The foaming mechanism is based on the effect that the foaming gas such as nitrogen is replaced with water and the foaming gas such as nitrogen gas is generated, and the fine bubbles of this gas are uniformly generated in the material. It is speculated that foamed solids are produced. Nitrogen gas is a stable gas, and because it is nonflammable, there is no risk of explosion.

The highly expandable zeolite obtained by the method of the present invention comprises 10 to 40% by weight and 60 to 40% by weight of a setting hardening material.
By mixing at a ratio of 90% by weight, a composition for a gap filling material for civil engineering and construction work can be obtained.

The setting and hardening material is, for example, at least one kind of aggregate such as cement, gypsum, lime, slaked lime, or a mixture thereof, or fine aggregate such as sand, coarse aggregate such as gravel and gravel. Or, at least one kind of filler such as clay, fly ash, slag, shirasu, etc., or a composition prepared by mixing both of these aggregate and filler.

Further, in the composition for filler, at least one selected from a foaming agent, a foaming agent, a quick-curing additive and a viscosity-imparting agent can be blended as an admixture.

The foaming agent may be any foaming agent as long as it can physically introduce bubbles, and examples thereof include those containing an anionic surfactant, a nonionic surfactant or an alkyl sulfonate as a component. be able to.

The foaming agent may be any as long as it can generate a gas by a chemical reaction, and for example, aluminum powder, magnesium powder or the like is used.

The rapid-curing additive is not particularly limited as long as it can impart rapid-hardening property. For example, water-glass, aluminate, quick-setting inorganic salt such as carbonate such as sodium carbonate, calcium. A material containing at least one quick-setting agent as a main component such as sulfoaluminate is used.

The viscosity-imparting agent is not particularly limited as long as it can impart viscosity, and examples thereof include clay minerals such as bentonite and sepiolite, and organic compounds such as carboxymethyl cellulose, cellulose ether compounds and acrylic polymer compounds. A thickener or the like is used.

The composition for a filler can be mixed with water to prepare a gap filler for civil engineering and construction work. The blending ratio of water is selected in the range of 10 to 100% by weight, preferably 15 to 70%, based on the weight of the mixture of highly expandable zeolite and setting hardening material.

Among the gap filling materials, the simplest composition is a mixture of 60 to 90% by weight of the setting hardening material and 10 to 40% by weight of the highly expandable zeolite prepared by the method of the present invention. It can be produced by adding 10 to 100% by weight, preferably 15 to 70% of water. Here, if the ratio of the highly expandable zeolite in the mixture of the highly expandable zeolite and the setting hardening material is less than 10% by weight, the amount of foaming is small at the time of construction and the effect is not sufficiently exerted, and if it exceeds 40% by weight. The strength is unavoidable. Further, the ratio of water to the mixture is 10% by weight.
If it is less than 100% by weight, the slurry is not sufficiently formed and the effect is not sufficiently exhibited. If it exceeds 100% by weight, the strength is unavoidably lowered.

The void gap filling material for civil engineering and construction works is to fill the voids in civil engineering works and construction works, and the "voids" are voids, cavities or defective portions to be repaired or reinforced. This means, for example, the void between the tunnel lining and the ground, the void on the back of the underground structure, the void caused by subsidence, the void or void in the ground, and the void in the backfill part due to underground construction work. .

The foaming of the above gap filling material usually continues for about 1 to 5 hours, but after about 5 to 20 minutes after kneading, the foaming amount is about 50 to 80% of the final foaming amount, so the remaining 50 to 2 minutes.
Due to a foaming reserve of about 0%, even after the gap filling of the gap filling material is completed, the gap filling material expands and intrudes into the small voids, and good gap filling performance is obtained.

For example, in filling a cavity in the back surface of a tunnel lining, the filling pressure is generally controlled by taking into account the influence on the lining and a relatively small injection pressure of 2-3 kgf / cm ² is used as a guide. In the case where cracks are generated in or the winding thickness is insufficient, the injection pressure is further reduced. However, with such a small injection pressure, it is difficult to perform sufficient filling, and there is a risk of leaving an unfilled portion even after filling. Therefore, post-filling property is demanded in order to make up for such a lacking filling part.

As described above, the gap filling material is filled in the gap in the civil engineering work and the construction work, and slowly foams for several tens of minutes at the time of the gap filling work. Even if the injection is completed under a small injection pressure that has no influence, good filling can be expected due to the subsequent foaming of the filler. Moreover, the foaming pressure of the filling material is minute (1 kgf / cm ² or less), and unlike the filling material that uses aluminum powder or the like that produces a foaming pressure of several kgf / cm ² or more, there is a concern about the influence on the lining. There is no. Further, since the bubbles generated by the foaming are fine and highly uniform, there is very little possibility that the bubbles in the surface layer portion will escape and the volume will decrease as in the conventional foaming agent. Therefore, such a gap filling material is extremely suitable for purposes such as backfilling of the tunnel lining portion, reinforcement of the lining, and filling of the gap on the rear surface of the underground structure.

The characteristics of the above gap filling material will be described with reference to the accompanying drawings. FIG. 2 shows a blending ratio of the zeolite to the cement for the filling material in which the ratio of water to the total amount of the cement and the highly expandable zeolite is 60% by weight. It is a graph which shows the relationship between a foaming amount.

From this, by increasing the amount of the highly expandable zeolite, the foaming amount increases almost proportionally up to a certain point, for example, in the case of FIG. It can be seen that if the amount exceeds the above range, the foaming amount does not increase so much even if the content of the zeolite is increased.

Further, in FIG. 3, the following composition A-1, A-2, X and Y for gap filling material containing various foaming substances was kneaded together with 60% by weight of water. The relationship between the elapsed time from the preparation of the filling material and the foaming amount is shown in the graph. A-1 and A-2 are for reference of fillers, and are cement and 20 ° C after firing to 500 ° C.
The weight ratio with the calcined zeolite cooled to 2 is 2 in the former case.
1, the latter is 5: 1, X and Y are for comparison, and X is 0.3% by weight of a foaming agent (Sanko Colloid Co., Ltd., trade name Sanko GP) to cement. Y is a composition obtained by mixing 0.03% by weight of aluminum with respect to cement.

From this graph, when the conventional foaming agent is used, there is almost no change in the foaming amount with the passage of time,
Further, when the conventional foaming agent is used, the foaming amount increases rapidly after 3 minutes, whereas the gap using the expandable zeolite for reference of the filler using the highly expandable zeolite of the present invention. In the composition for a filler, after 10 minutes, about 60 to 70% of the final amount of foaming was foamed, and about 40 to 30% of the remaining amount of foaming was gradually foamed, and the filling was insufficient even after the filling construction work. It can be seen that the filler penetrates into the portions and small voids, and an excellent gap filling effect is obtained.

The void-filling material using the highly expandable zeolite obtained by the method of the present invention has a void-filling effect similar to that for this reference and, in addition, causes a larger amount of foaming than this. It is even better because you can

Next, a gap filler obtained by adding 60% by weight of water to a mixture of 5 parts by weight of cement and 1 part by weight of the highly expandable zeolite was kneaded with a mixer at 140 rpm and cast. It was placed in a mold and left for 1 day to solidify. The breathing amount and foaming amount generated in this process were measured. In addition, the whole solidified product was cut into upper, middle, and lower three layers, and the average unit volume weight of each was determined. The results are shown in the table.

For comparison, water was added to cement 6
60% by weight of water and a foaming agent (manufactured by Sanko Colloid Co., Ltd. under the trade name Sankou), based on the cement, and a gap filler made of 0% by weight and 0.03% by weight of aluminum powder (hereinafter referred to as Comparative Sample 1). GP) 0.03% by weight of the gap filler (hereinafter referred to as Comparative Sample 2) in the same manner as the above filler, the amount of breathing after consolidation, the amount of foaming and the average unit of the upper, middle and lower three layers. The volume weight was determined. The results are also shown in the table.

[0031]

[Table 1]

As a result, the comparative samples 1 and 2 both had a large amount of breathing, and in the case of the comparative sample 2, the lower layer had a higher average unit volume weight. While the uniformity is unavoidably deteriorated, it can be seen that the filler using the highly expandable zeolite has a small amount of breathing and is excellent in uniformity after consolidation.

[0033]

According to the method of the present invention, it is possible to easily produce a highly expandable zeolite in which the foaming gas is safe and the foaming is performed relatively slowly. Further, the highly expandable zeolite obtained by the method of the present invention is used to prepare a filler for filling a gap in civil engineering and construction work, and this filler is safe and has a small amount of breathing during construction,
Foaming progresses relatively slowly, foaming pressure is moderate, workability is good, gap filling can be done without excess and deficiency, uniformity after consolidation is excellent, and an extremely large amount of foaming can be obtained. Because of its excellent effect, civil engineering and construction work, especially backfilling of tunnel linings and reinforcement of linings, filling of cavities caused by gaps in the back of underground structures and ground subsidence, soft ground improvement work, especially for soft ground It can be suitably used for filling voids in the ground during consolidation and injection work, and for backfilling due to underground buried work.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the cooling temperature and the foaming amount of calcined zeolite.

FIG. 2 is a graph showing the relationship between the compounding ratio of the zeolite to the cement of one example of the gap filling material using the highly expandable zeolite prepared by the method of the present invention and the foaming amount.

FIG. 3 is a graph showing the relationship between the elapsed time from the preparation of various fillers and the foaming amount.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Kimura 2-6-15 Hamura-cho, Nishitama-gun, Tokyo (56) References Japanese Patent Publication Sho 55-35352 (JP, B2)

Claims (1)

(57) [Claims] 1. A method for producing a highly expandable zeolite, which comprises firing zeolite to 100 to 700 ° C. and then forcibly cooling it to a low temperature of 10 ° C. or lower in dry air.