JP2618732B2 - Mixed composition mainly composed of asphalt emulsion - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mixed composition mainly composed of an asphalt emulsion suitable for use as a backing material for a tunnel.

[Conventional technology]

Conventionally, cement-based mortar has been used as a backing material for tunnels, and the gap between the ground excavated by the shield method and the outer peripheral surface of the segment is filled with the mortar and hardened more firmly than the ground, and the collapse of the ground To prevent groundwater from entering the tunnel from the ground.

In addition, the present inventors disclosed in Japanese Patent Application No. 63-321319, as a composition for absorbing the vibration of the tunnel ground during an earthquake, an asphalt emulsion obtained by dispersing asphalt in water containing an emulsifier, and the hardening of cement and the like. A mixed composition mainly composed of an asphalt emulsion composed of a mixture of a material and a superabsorbent material was proposed.

[Problems to be solved by the invention] However, in Japan, which is one of the world's leading earthquake nations, it is natural that tunnels and other underground structures must be made highly seismic resistant to ensure safety. According to such a mortar filling structure, only the structure itself is given seismic resistance. Therefore, during an earthquake, seismic force is directly transmitted from the ground to the underground structure. In particular, when a tunnel is constructed between a hard ground and a soft ground, there is a problem that a large difference occurs in the deformation amount of these strata due to the earthquake, and the tunnel at the boundary is damaged.

On the other hand, when the latter composition containing asphalt emulsion as a main component is used as a backing material to be injected and filled between the segment and the ground in the shield method, it takes a long time to obtain a predetermined strength. Therefore, if the shield machine is propelled with the segment as a reaction material during that time, the reaction force cannot be transmitted to the nearby ground, which may hinder the direction control and pushing work of the shield machine. There was a point.

The present invention has been made in view of such problems,
It is an object of the present invention to provide a mixed composition containing asphalt emulsion as a main component, which can effectively absorb vibration energy for a structure or the like and can quickly develop an initial strength upon curing.

[Means for solving the problem]

In order to achieve the above object, a mixed composition containing an asphalt emulsion of the present invention as a main component is prepared by mixing a cement with an asphalt emulsion obtained by dispersing asphalt in water containing an emulsifier, and then rapidly mixing bentonite and the cement. And a mixture obtained by successively mixing a binder with the binder. The composition of these compositions is, specifically, 20 to 30% by weight of the asphalt emulsion to the asphalt emulsion. It is desirable to knead the cement, 3 to 15% bentonite and 5 to 15% cement quick setting agent.

[Action]

When cement is mixed as a hardening material into the asphalt emulsion and then bentonite is added, the mixture thickens and the bentonite contains the water in the asphalt emulsion to form a gelled mixed composition.

Further, when a cement quick-setting admixture is mixed with the gelled mixture, the hydration reaction of the cement in the mixture is promoted, and the initial strength of the mixture is increased.

This composition has a property that it is hardly diluted with water, and even if it is cured in air or water, it hardens gradually and uniformly due to the internal curability of cement.

The composition thus cured is softer than cement-based and slag-based materials, and has properties such as elasticity, waterproofness, adhesion, and viscoelasticity. This composition is used as a backing material for tunnels. In this case, the plasticity of the asphalt shrinks in accordance with the amount of ground fluctuation when an earthquake occurs, and absorbs vibration energy.

Also, it is softer than the ground due to hardening by cement, but has a certain strength, and does not flow even when subjected to earth pressure.

Further, as described above, the mixture is gelled by the incorporation of bentonite, thereby preventing the asphalt emulsion from being dispersed and diluted in water.

Further, by mixing the quick-setting agent of the cement, the cement is hardened early, the initial strength of the mixture is expressed in a short time, and when the mixed composition of the present invention is used as a backing material in a shield method. The propulsion reaction force of the shield machine can be effectively transmitted to the ground via the segments.

Further, since the mixture is cured in a state in which the water in the asphalt emulsion is contained in the bentonite, there is no fear that the mixture will undergo volume shrinkage due to the curing.

〔Example〕

Next, the embodiment of the present invention will be specifically described.As for the mixed composition, an asphalt emulsion obtained by putting straight asphalt having a penetration of 40 to 500 into water and dispersing the same with an emulsifier, cement, and bentonite And a mixture with a cement quick-setting agent, a gel substance having flexibility and moderate viscoelasticity, having waterproofness, adhesion, and corrosion resistance. Also have physical properties to be cured.

In order to obtain such a mixed composition, first, straight asphalt is dispersed in water containing an emulsifier to form an asphalt emulsion. This asphalt emulsion has a specific gravity of 1.0 to
1.05, PH is 7-8, and viscosity is adjusted to be about 11 seconds (7.5 seconds for water) as measured by the P-Rot method and about 15 seconds when cement described later is mixed. .

This asphalt emulsion can change the viscosity and stretchability of the obtained mixed composition by changing the penetration of straight asphalt as a main component from 40 to 500.

In addition, it is necessary that the asphalt emulsion does not decompose even when mixed with cement, that it is diluted even when mixed with water but does not decompose, and that it is not decomposed even when salt is mixed. is there.

This asphalt emulsion was added in a weight ratio of 2 to 100 parts by weight.
After mixing and stirring 0 to 30% of cement, 3 to 15% by weight of bentonite is mixed with the asphalt emulsion,
Furthermore, a desired mixture composition can be prepared by mixing and stirring the cement quick-setting agent with the asphalt emulsion in a weight ratio of 5 to 15%.

As the cement quick setting agent, sodium silicate type, aluminate type, carbonate type and the like can be used.

When mixing the respective components of the asphalt emulsion, cement, bentonite and quick-setting agent, first, the asphalt emulsion and cement are mixed, and then bentonite is mixed.When the mixing order is changed, for example, If the cement is mixed after the asphalt emulsion and the bentonite are mixed, the cement is difficult to disperse, and a uniformly mixed composition cannot be formed.
Finally, the cement quick-setting admixture is mixed to prepare a predetermined mixed composition.

In addition, even if the asphalt emulsion is allowed to stand for about one day, its properties such as viscosity do not change. Further, when the asphalt emulsion and the cement are mixed, the two are uniformly mixed, and even if the viscosity slightly increases with time, the usable time is about one day after mixing.

After mixing the asphalt emulsion with the cement and then mixing and stirring the bentonite, the bentonite absorbs the water in the asphalt emulsion and the mixture gels immediately.

When the cement quick-setting admixture is mixed with the gelled mixture and stirred, the hydration reaction of the cement in the mixture is promoted and the initial strength of the mixture can be increased.

Therefore, the mixture hardens before the asphalt emulsion is dispersed and diluted in the water in the ground, that is, while the water in the asphalt emulsion is included, so that the volume shrinkage of the whole mixture does not occur and the mixture is shielded. When used as a backing material in the construction method, the backing material hardens quickly to the same rigidity as the ground, and the propulsion reaction force of the shield machine acting on the segment can be transmitted to the ground.

The mixture composition thus gelled, and the initial strength developed, even if cured in air or water at room temperature, the cement gradually hardens, and can be plastically deformed against external pressure, and even if the deformation becomes large. When used as a backing material in the shield method, it has the physical properties that it does not crack and follows the ground vibration in combination with the asphalt composition and the viscosity of bentonite. Absorb energy.

 Next, specific examples and comparative examples of the present invention will be described.

(Example 1) Asphalt emulsion was prepared by mixing 60% by weight of straight asphalt and 40% by weight of water and dispersing asphalt with an emulsifier. Next, 30 parts by weight of cement was mixed with 100 parts by weight of the asphalt emulsion, and after stirring, 6 parts by weight of bentonite was added and mixed, followed by stirring. Further, 7.5 parts by weight of a cement quick setting agent was added and mixed. Stirred.

After curing this mixed composition for 7 days,
A compression test was carried out at 50 mm and a height of 100 mm in a columnar shape, and at a normal temperature, the entire upper surface was uniformly lowered at a rate of 1 mm / min. The results are shown in FIG.

(Example 2) In Example 1, 25 parts by weight was mixed with 100 parts by weight of asphalt emulsion as a cement component in the mixed composition, and a mixed composition was prepared by mixing the other components in the same proportion. After curing the mixed composition for 7 days in the same manner as in Example 1, the composition was formed into a columnar shape having a diameter of 50 mm and a height of 100 mm.
A compression test was performed at 1 mm / min. The result is shown in FIG. 1 (B).

(Example 3) In Example 1, as a cement component in the mixed composition, 20 parts by weight was mixed with 100 parts by weight of the asphalt emulsion, and the mixing ratio of the other components was made the same to prepare a mixed composition. After curing the mixed composition for 7 days in the same manner as in Example 1, the composition was formed into a columnar shape having a diameter of 50 mm and a height of 100 mm.
A compression test was performed at 1 mm / min. The result is shown in FIG. 1 (C).

(Comparative Example) 20 parts by weight of bentonite with respect to 100 parts by weight of cement
Mix and stir 290 parts by weight of water, and further add cement quick setting agent 30
After mixing and stirring the parts by weight to prepare a mixed composition, this mixed composition was cured for 7 days in the same manner as in Example 1, and then the composition was formed into a columnar shape having a diameter of 50 mm and a height of 100 mm, and then cooled at room temperature. Then, a compression test was performed on the entire upper surface uniformly at a descent speed of 1 mm / min. The result is shown in FIG. 1 (D).

As is clear from this figure, in the comparative example as the conventional cement material, the strength is large but no plastic deformation is caused, whereas in the example of the present invention, the strength is small but the plastic deformation is small as compared with the comparative example. I can understand.

(Example 4) Cement 30 was added to 100 parts by weight of the asphalt emulsion.
After mixing and stirring, 6 parts by weight of bentonite was added, mixed and stirred, and then 10 parts by weight of a cement quick setting agent was mixed and stirred to obtain a composition mainly composed of asphalt emulsion.

FIG. 2 (a) shows the result of measuring the amount of penetration of this mixed composition every time by using a cone penetrometer and converting it into compressive strength.

(Comparative Example) Cement 30 was added to 100 parts by weight of the asphalt emulsion.
After mixing by weight, 4 parts by weight of the superabsorbent polymer was mixed and stirred to obtain a composition mainly composed of asphalt emulsion.

FIG. 2 (b) shows the results obtained by measuring the amount of penetration of this mixed composition every time by using a cone penetrometer and converting it into compressive strength.

As is clear from this figure, it can be understood that the mixed compositions of the examples have higher initial strength and initial rigidity than the comparative examples.

〔The invention's effect〕

As described above, the mixed composition containing the asphalt emulsion of the present invention as a main component is prepared by mixing an asphalt emulsion obtained by dispersing asphalt in water containing an emulsifier and a cement, and then using bentonite and a quick setting agent for the cement. Since it is characterized by being sequentially mixed, this mixed composition is softer than the cement-based and slag-based materials after curing, and has physical properties such as elasticity, waterproofness, adhesion, and viscoelasticity. When used as a backing material for tunnels, the plasticity of asphalt and the viscosity of bentonite that retains water combine to compress according to the amount of ground fluctuation during an earthquake, absorb vibration energy, and transmit vibration to the tunnel And it is excellent in elasticity, is less likely to crack, and can stop groundwater outside the backing material.

Further, as described above, the mixture can be thickened by adding bentonite to the mixture of the asphalt emulsion and the cement, and when the cement quick setting agent is mixed, the moisture in the asphalt emulsion is included by the bentonite. In addition to preventing the asphalt emulsion from dispersing and diluting in water as it gels, the cementitious setting agent is mixed into this gelled mixture to cure the cement early. Therefore, the initial strength of the mixed composition is developed in a short time, and when this mixed composition is used as a backing material in the shield method, the propulsion reaction force of the shield machine is effectively applied to the ground via the segments. Can be transmitted to

Further, since the mixture is cured in a state in which the water in the asphalt emulsion is contained in the bentonite, the mixture has many features such that there is no risk of causing volume shrinkage due to the curing.

[Brief description of the drawings]

FIG. 1 is a compression-strain diagram of the mixed composition of the example of the present invention and the conventional mixed composition, and FIG. 2 is a comparison of the compressive strength of the mixed composition of the example of the present invention and the conventional mixed composition. FIG.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication C04B 14:10 24:36) 111: 70 (72) Inventor Ichiro Fukai Kashiwaoka, Makomanai, Minami-ku, Sapporo-city, Hokkaido 9-7-7 (72) Inventor Akihiro Moriyoshi 1-9-9, Kiyota 2-jo, Toyohira-ku, Sapporo-shi, Hokkaido 10-72 (72) Mikio Takeuchi 2-2-2 Matsuzakicho, Abeno-ku, Osaka-shi, Osaka 2-2 Okumura Gumi Co., Ltd. (72) Inventor Yoshiaki Iwata 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka-shi Inside Okumura-gumi Co., Ltd. (72) Inventor Kenichiro Ohno 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka 2, Okumura-gumi Co., Ltd. (56) References JP-A-55-69651 (JP, A)

Claims (2)

(57) [Claims] (1) mixing an asphalt emulsion obtained by dispersing asphalt in water containing an emulsifier and cement;
A mixed composition comprising asphalt emulsion as a main component, wherein bentonite and the cement quick setting agent are sequentially mixed. 2. The asphalt emulsion according to claim 1, wherein 20 to 30% of cement, 3 to 15% of bentonite and 5 to 15% of cement quick setting agent are kneaded by weight of the asphalt emulsion. A mixed composition containing asphalt emulsion as a main component.