JPH0230826A - Method of connecting concrete structure using water swelling rubber - Google Patents

Abstract

PURPOSE:To enable a water stopping effect to be displayed for a long period by placing a joint member made of sponge-shaped water swelling rubber having a plurality of bubbles in the internal section between the connecting surfaces of concrete structural-bodies to fasten the structural bodies together, and by consolidating the joint member. CONSTITUTION:Between the connecting end surfaces 1a, 2a of box culverts 1, 2 to be connected, a joint member 3 made of sponge-shaped water swelling rubber having bubbles 3a in the internal section is placed, and both the structural bodies 1, 2 are fastened together in the mutually approaching direction, and the joint member 3 is consolidated. When the joint 3 is exposed to water, then cubic expansion is generated on elastic rubber organization, and pressure due to deformation constraint is generated, and the joint member 3 is firmly pressure-fitted on the connecting surfaces 1a, 2a, and secondary water-stopping effect is displayed. As a result, not only initial water-stopping effect but high water-stopping effect for a long period can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the joining of concrete structures using water-expandable rubber, which is suitably used when joining concrete structures such as so-called box culverts and cabs. It is related to construction methods.

[Conventional technology] Water supply and sewerage systems that need to prevent internal water from leaking to the outside, and communal ditches that need to prevent external groundwater from entering the interior are constructed using secondary concrete products. In such cases, water-stopping measures must be taken at the joints of the concrete structures that are secondary products.

Conventionally, when joining such concrete structures, a joint material made of ordinary synthetic rubber or a joint material made of water-expandable rubber was interposed between the joint surfaces. ing.

[Problems to be Solved by the Invention] Since a joint material made of ordinary synthetic rubber has relatively high elasticity, a water-stopping effect can be expected from the beginning by appropriately compacting it. However, joint materials made of such materials have a problem in that when the rubber becomes fatigued due to long-term use and so-called sagging occurs, the water-stopping effect thereof decreases rapidly.

On the other hand, joint materials made of water-expandable rubber expand in volume when exposed to water and are crimped to the joint surface.
Demonstrates high water-stopping effect over a long period of time. However, the water-expandable rubber currently being developed is hard before it comes into contact with water, and conventional joint materials made by tightly molding such hard materials lack elasticity. Therefore, there is a problem in that it is difficult to eliminate gaps even when tightened quite strongly, and it is difficult to effectively prevent water leakage in the initial stage.

The present invention aims to solve such problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

In other words, the method for joining concrete structures using water-expandable rubber according to the present invention is such that when joining concrete structures placed in locations exposed to water, there is a A joint material made of water-expandable rubber having a spongy shape with a large number of air bubbles is interposed, and the two concrete structures are tightened in a direction toward each other to consolidate the joint material.
It is characterized by.

[Function] When water-expanded rubber is made into a sponge-like material with many bubbles inside, even though the rubber structure itself is hard as before, the joint material as a whole becomes highly elastic. becomes possible.

Therefore, when this joint material is interposed between the joint surfaces and tightened, the surface of the joint material flexibly adheres to the joint surface due to its elasticity, thereby preventing water from leaking in the initial stage.

When this joint material comes into contact with water, the water-expandable rubber structure causes volumetric expansion, and pressure is generated due to the volumetric expansion and deformation restraint. As a result, the joint material is more strongly crimped onto the joint surface. Therefore, it is possible to continue exhibiting the water-stopping effect over a long period of time.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 4.

This embodiment is for joining a box culvert 1.2 which is a concrete structure, and FIGS. 1 to 3 are cross-sectional views of the side wall portion of the box culvert 1.2.

First, in this construction method, as shown in Fig. 1, between the joint end faces 1as2a of the box culverts 1.2 to be joined,
A joint material 3 is interposed. This joint material 3 is
It is made of water-expandable rubber with many bubbles 3a inside.
It has a string shape and is adhered to one joint surface 1a using an adhesive, for example. This joint material 3 is made of ordinary water-expandable rubber, and contains 10 to 100 μm of water in the material.
It is made by entraining bubbles 3a of about m size, for example, the one of this example has 20-30% open cells,
Closed cells account for 80-70%. and,
The specific gravity before firing, that is, the specific gravity of the water-expandable rubber material is 1.
3, and the specific gravity of the joint material 3 with air bubbles 3a is 0.
．． 75, the porosity is approximately 42%.

Next, the box culverts 1.2 are tightened in the direction toward each other, and the joint material 3 is consolidated. For example, the method of tightening box culverts 1 and 2 is as follows:
Box culvert 1.2 using PC steel bars (not shown)
There are methods such as attracting them together and applying prestress. As a result, the joint material 3 is attached to the box culvert 1.
．． The joint surfaces 1a and 2a of the two are compressed and compacted. The tightening force is set to such a value that the deformation of the joint material 3 is within its elastic deformation region. That is, in this embodiment, as shown in FIG. 4, a use range A is set within the elastic deformation region, and the target is set at the center point B within the range A for tightening.

As described above, when the water-expandable rubber constituting the joint material 3 is made into a sponge-like material with many bubbles 3a inside, even though the rubber structure itself is hard as before,
The joint material 3 as a whole has relatively high elasticity. Therefore, as shown in FIG. 2, when this joint material 3 is interposed between the joint surfaces 1as2a and tightened, its elasticity causes the surface of the joint material 3 to
It adheres flexibly to the a s2a and prevents water from leaking in the initial stage.

When this joint material 3 is exposed to water, its elastic rubber structure causes volumetric expansion, as shown in FIG.
Pressure is generated due to deformation restraint, and the joint material 3 is more strongly crimped to the joint surfaces 1a and 2a. Therefore, it becomes possible to continue exhibiting the water-stopping effect over a long period of time.

Therefore, according to such a joining method, it is possible to achieve both a so-called primary water-stopping effect immediately after construction and a so-called secondary water-stopping effect during use at a high level.

In the above examples, the case where ordinary water-expandable rubber was used as the material for the joint material with air bubbles was explained. Water-expandable rubber may also be used.

Further, the shape of the joint material is not limited to the embodiments described above, and may be, for example, as shown in FIGS. 5 and 6. That is, this joint material 13 has a substantially triangular cross section, and has not only air bubbles 13a but also cavities 13b continuous in the longitudinal direction.
It also has With such a configuration, a large deformation can be obtained without difficulty, which is advantageous when there is a large variation in joint width. The joint material 13 having this shape has a small pressure receiving area when the deformation is relatively small. Therefore, even in cases where the joint width cannot be reduced, a relatively large adhesion pressure can be obtained.

Furthermore, the concrete structure to which the present invention is applied is, of course, not limited to box culverts, and can be similarly applied to cabs and other structures.

[Effects of the Invention] Since the present invention has the above-described configuration, it provides a concrete structure using water-expandable rubber that can achieve both secondary water-stopping effect and secondary water-stopping effect at a high level. It is possible to provide a method for joining the body.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, Figures 1, 2, and 3 are cross-sectional views showing the steps in sequence, and Figure 4 shows the deformation characteristics of the joint material. It is an explanatory diagram. FIGS. 5 and 6 are cross-sectional views showing other embodiments of the present invention. 1.2...Concrete structure (box culvert) 1a, 2a...Joint surface 3.13...Joint material 3 a s 13 a...Bubble 13b...Cavity Fig. 2 Fig. 3

Claims (1)

[Claims] When joining concrete structures that are placed in locations exposed to water, a spongy water-expandable rubber joint material with many internal bubbles is interposed between the joint surfaces of the concrete structures. . A method for joining concrete structures using water-expandable rubber, characterized in that the two concrete structures are tightened in a direction toward each other to consolidate the joint material.