JPS585346B2 - Processing method for joints in reverse pouring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating a spliced joint in a reverse pouring method.

No matter how carefully the post-cast concrete is placed in the vertical joints of the reverse casting method, laitance accumulates as breathing increases, and it is difficult to avoid some settling of the top surface of the post-cast concrete, resulting in gaps. is likely to occur.

Particularly in modern buildings with complex cross-sections, if construction is done carelessly, large gaps will clearly form on the exterior surface, which may not only improve the appearance but also cause problems such as lack of strength and water leakage, so some sort of treatment may be required. many.

As this processing method, injection method and filling method are known.

As shown in Figure 1, the filling method is pre-cast concrete and C1.
Pour the post-cast concrete C2 in a completely divided state so that a large gap is formed between the concrete and the concrete, cover the area around the gap with formwork a, and put cement paste containing an expansive material inside it. It is the most reliable and effective method of filling.

However, this method is very costly, and until now traps have rarely been used unless there is a very good reason.

Incidentally, the current cost ratio is approximately as follows, assuming that the case where no processing is performed on the joining part (mere joining) is set to 1.

Mere joint: Injection method: Filling method = 1:3.6:8 Therefore,
Considering cost, it is currently necessary to adopt the injection method to treat the joints.

An example of the conventional injection method is as shown in Figures 2 and 3.
Alternatively, a grooving groove d is provided in the pre-cast concrete C1,
After pouring the post-cast concrete C2, use them to inject cement paste containing an expanding material into the joint, and (b) After pouring the post-cast concrete C2 without making any preparations for injection in advance. There is a method of drilling an injection hole with a drill etc. along the joint and injecting from this hole, but these injection methods are currently unreliable and have not been adequately processed. It is.

That is, in method A, since the injection pipe C and the injection groove d are used to form an empty space for injection before pouring the post-cast concrete C2, clogging occurs due to the pouring of the post-cast concrete C2, which prevents the pouring. Often disabled or incomplete.

In addition, with the drilling method, even if a drill is used, it is not possible to drill deeply because steel frames, reinforcing bars, etc. are located inside the joint, and on the other hand, the gaps at the joint are not necessarily uniform. Rather, since gaps often form around the internal steel frame, injection is performed only near the surface and may not be able to reach the inside.

The present invention proposes a processing method that can eliminate these drawbacks of conventional methods. Post-cast concrete is poured with a formwork for making injection holes placed on the bottom of pre-cast concrete, and post-cast concrete is placed on the bottom of the pre-cast concrete. The method is characterized in that after the concrete hardens, the formwork is removed to create an injection hole, and an injection agent such as a cement paste containing an expansive material is injected into the joint through the injection hole.

In addition, as a method for removing the formwork in the present invention, there are a method of pulling out the formwork and a method of dissolving it with a solvent, as described later.

Embodiments of the present invention will be described below based on the drawings.

First, as shown in Figure 4A, pre-cast concrete C1
A formwork 1 for making injection holes located along the bottom surface of the concrete is supported by a formwork 2 for post-cast concrete so that it can be extracted.

In this state, as shown in Figure 4, post-cast concrete C2
to be poured.

After the post-cast concrete C2 has hardened to a certain degree, that is, when it has hardened to an appropriate hardness that allows for quick dismantling of the formwork 2, but allows for forming since no large load is applied from above at the joints. As shown in FIG. 4C, the mold 1 for making injection holes is removed by operating from the outside of the mold 2, and injection holes 8 for the splicing part are formed.

When the post-cast concrete C2 has hardened to a hardness that allows it to be removed from the mold, the formwork 2 is dismantled and a pouring agent 4 such as cement paste containing an expansive material is injected through the injection hole 3, as shown in FIG. 4 2 and E. .

This injection work is carried out by sealing the area around the joint near the injection hole 3 to prevent the injection agent 4 from leaking from near the opening end of the injection hole 3 in a short-circuit manner. Since this is the same as the above, illustrations and explanations will be omitted.

According to the above embodiment, since the injection hole 3 is created after pouring the post-cast concrete C2, there is no clogging and effective injection can be performed to the inside of the joint.

Furthermore, since the injection hole forming form 1 is removed before the post-cast concrete C2 is completely hardened, the removal work can be easily performed.

Note that after the post-cast concrete C2 has completely hardened and the formwork 2 has been dismantled, it is also possible to remove the formwork 1 for making injection holes, but in this case, the formwork 1 is formed into a wedge shape. Consideration must be taken to facilitate removal, such as applying a mold release agent such as grease to the surface of the mold 1.

FIG. 5 shows a suitable example thereof.

The injection hole making mold 1 shown in the figure is made by spirally winding a resin tape 1a into a cylindrical shape.By pulling one end in the axial direction, the overlapping margin of the resin tape 1a is reduced, and the cylindrical shape is Since the frame 1 is reduced in diameter, even after the post-cast concrete C2 has completely hardened, it can be pulled out with a slight force.

Figures 6A to 6H show another embodiment, and formwork 1 for making injection holes.
A formwork made of synthetic resin such as styrofoam is used as a mold, and with this synthetic resin injection hole making formwork 1 attached to the bottom of pre-cast concrete C1, post-cast concrete C2 is poured, and after hardening, the mold The injection hole 3 is formed by dismantling the frame 2, pouring a solvent such as thinner, and melting the injection hole making mold 1 made of synthetic resin.

That is, first, as shown in FIG. 6A, a plurality of molds 1 for making injection holes made of synthetic resin and having any shape and thickness are attached to the bottom of pre-cast concrete C1.

This attachment may be done by attaching it to the bottom surface of the pre-cast concrete C1 with packing tape or adhesive 5 after demolding the pre-cast concrete C1, as shown in FIG. 7, or as shown in FIG. As shown, pre-cast concrete C1 is temporarily fixed on the upper surface of the bottom plate of a form 6 for producing pre-cast concrete, and when the mold is removed, the form 1 is placed on the pre-cast concrete C1 side, and its bottom surface and It may also be done by leaving it flush.

Next, as shown in Figure 6, a formwork 2 is assembled and post-cast concrete C2 is placed inside it.

After the post-cast concrete C2 has hardened, the formwork 2 is dismantled as shown in FIG. 6, and the selvage C'2 formed at the post-cast concrete inlet is scraped off.

After that, a solvent such as thinner is poured into the formwork 1.
As shown in Figure 6 2 and Figure 9, fill the inlet 3.
form.

In addition, 7 in the figure is a steel frame.

Next, as shown in FIG. 6E, the injection agent 4 is injected from the injection hole 3 into the splicing part.

As mentioned above, this injection work is performed by sealing the area around the spliced joint, similar to the conventional injection method.

A plurality of injection holes 3 are formed, and while one injection hole 3 is injecting, any other injection hole 3 serves as an air vent.

According to the above embodiment, since the injection hole 3 is drilled after the post-cast concrete C2 hardens, the post-cast concrete C
There is no need to worry about clogging caused by the mold 1, and since the mold 1 is removed by melting the mold 1, it is possible to use a curved mold 1.
An injection hole 3 having a desired shape and depth can be obtained.

Therefore, the injection process for the joint can be carried out very effectively.

Furthermore, the amount of dissolved residue is almost negligible, and has almost no effect on injection.

Of course, after melting, it is possible to inject water with a hose to wash away the thinner (which has no negative effect on the concrete) and the melt residue, but according to model experiments, the water-washed injection hole 3
There was almost no difference in the condition of the spliced joint after the injection work and the injection treatment for injection hole 3, which was not washed with water.

In the above example, since the post-cast concrete C2 is poured into the formwork 2 from the funnel-shaped inlet formed at the upper end of the formwork 2, the composite material is formed by scraping off the ear part C'2. The end of the mold 1 for making resin injection holes is exposed, but as shown in FIG. If this is done, the solvent can be poured in before the edge portion C'2 is printed.

In addition, as shown in Fig. 11, light lamp concrete C1
If the post-cast concrete C2 can be cast without forming an ear, such as by pouring the post-cast concrete C2 through a vertical sleeve 8 buried in the synthetic resin injection hole forming form 1. If the post-cast concrete C2 is poured with the outer end surface of the mold 2 in contact with the inner surface of the formwork 2, the solvent can be poured immediately after demolding.

The material resin for the synthetic resin mold 1 for making injection holes may be any synthetic resin that easily dissolves in a solvent and leaves no harmful substances, such as styrofoam, for example.

Solvents for this include the above-mentioned organic solvents that act as thinners, aromatic solvents such as toluene, benzene, and xylene, halogenated hydrocarbons such as ethylene dichloride and trichloroethylene, and
Any harmless solvent capable of dissolving expanded polystyrene such as esters such as butyl acetate or ethers such as dioxane can be used.

The present invention has the above-mentioned configuration, and since the injection hole is formed after the post-cast concrete has hardened, there is no risk of clogging due to the post-cast concrete, and the injection hole can be made to any depth. It is possible to perform injection treatment reliably and well to the inside of the part.

In particular, as in the example, when a mold for making injection holes made of synthetic resin such as styrofoam is used and the injection holes are made by melting it, injection holes of arbitrary shapes can be easily created. Therefore, the injection effect can be further improved.

[Brief explanation of the drawing]

Figures 1 to 3 are longitudinal sectional views showing the conventional method, and Figure 4 is a vertical sectional view showing the conventional method.
Figures A, C, C, II, and H are longitudinal cross-sectional views showing embodiments of the present invention, Fig. 5 is a perspective view showing an example of a mold for making injection holes, and Fig. 6
Figures A, C, C, II, and H are longitudinal sections showing other embodiments of the present invention, and Figs. 7 and 8 are longitudinal sections showing a method for attaching a mold for making injection holes to concrete with light lamps, respectively. FIG. 9 is a cross-sectional view of the joining part showing the injection hole, and FIGS. 10 and 11 are longitudinal cross-sectional views of main parts showing another embodiment. C1... Pre-cast concrete, C2... Post-cast concrete 1... Formwork for making injection holes, 3... Injection holes, 4... Injection agent.

Claims (1)

[Claims] 1 Post-cast concrete is placed with a formwork for making injection holes placed on the bottom of pre-cast concrete, and after the post-cast concrete hardens, the formwork is removed to create injection holes. A method for treating a spliced joint in a reverse pouring method, which comprises: injecting a filler such as cement paste containing an expansive material into the spliced joint from the injection hole. 2 As the mold for making the injection hole, a mold made of a synthetic resin such as styrofoam that easily dissolves in a solvent and leaves no harmful substances is used, and the removal of the mold makes the synthetic resin mold 2. A method for treating a spliced joint in a reverse pouring method according to claim 1, characterized in that the treatment is carried out by melting the spliced part in the reverse pouring method. 3. The method for treating a spliced joint in a reverse pouring method according to claim 2, wherein the synthetic resin is styrofoam and the solvent is a thinner.