JP3845404B2 - Cross-section repair and peeling prevention combined construction method - Google Patents

Description

  The present invention relates to a method for combined use of repairing a cross section of an existing concrete structure such as an expressway and preventing peeling.

  In existing concrete structures such as expressways, the rebars rust and expand due to water penetration from cracks, salt damage, and other factors. is there. When it peeled off, the concrete in which the peeled part deteriorated was removed with a water jet or the like, and then a polymer cement mortar was placed to repair the cross section.

On the other hand, in order to prevent peeling, there is a peeling prevention method in which a peeling prevention net is bonded to the surface of an existing concrete structure with an epoxy resin.
As a technique applicable to such an exfoliation prevention method, when a new existing concrete structure was made, a fiber sheet was temporarily fixed to the inner surface of the concrete formwork, a reinforcing bar was installed, and the concrete was placed in the formwork. After that, there is a method of waiting for hardening and removing the mold and constructing an existing concrete structure (Patent Document 1).
JP 2001-348999 (paragraph 0023, FIG. 1, FIG. 3, etc.)

However, the technique described in Patent Document 1 is a method of providing a fiber sheet when newly constructing an existing concrete structure, and cannot be applied when repairing a cross-section of a peeled portion. In addition, in order to provide a peeling prevention net at the time of cross-sectional repair, it is necessary to rough the surface after finishing the cross-section repair with a disk sander etc., and to adhere the peeling prevention net with epoxy resin, which is very laborious and time consuming. It was a thing. This procedure is shown in the flowchart of FIG.
This invention is made | formed in view of such a problem, and provides the cross-section repair and peeling prevention combined construction method which can solve the said subject.

In order to achieve the above-mentioned object, the present invention is a combined method of repairing and preventing the cross-section of an existing concrete structure from which concrete has been peeled, wherein the concrete in the peeled portion of the existing concrete structure is used in two orthogonal reinforcing bars. Until the entire circumference of the steel bar is exposed and in the vicinity of the steel bar , the surface treatment step for removing the side and upper surface smoothly so as to be parallel to the steel bar to be exposed, and cutting the rusted part of the steel bar in the stripped part, A joint process for connecting a new reinforcing bar, a spraying process for spraying a basic mortar to the surface of the reinforcing bar, and a leveling process in which the basic mortar is attached to all of the reinforcing bars and boiled so as to eliminate voids; A second spraying step of spraying a surface mortar on the surface of the basic mortar leveled by the leveling step, and before the surface layer mortar is cured, And a Nurikomi step rub the fiber sheet to the surface layer mortar while leveling the surface of the barrel in iron, said fiber sheet, the fibers are arranged in a grid, lattice is triangular, three-axis vinylon fibers The basic mortar and the surface layer mortar are polymer cement mortar, and the spraying step and the second spraying step are performed in a plurality of times according to the thickness of the basic mortar and the surface layer mortar. Features.
The existing concrete structure is characterized in that the cross-section is repaired by the combined cross-section repair and peeling prevention method described above.

  ADVANTAGE OF THE INVENTION According to this invention, the cross-section repair and peeling prevention of the peeling part of an existing floor slab can be performed simply, and the cross-section repair and peeling prevention combined construction method which shortens a process and improves economically significantly can be provided.

  Next, the contents of the present invention will be described in detail, but the present invention is not limited to these embodiments.

  With reference to FIG. 1 to FIG. 7, a method for combined cross-sectional repair and peeling prevention of a peeled portion of an existing concrete structure (existing floor slab C) according to an embodiment of the present invention will be described.

  FIG. 1 is a flowchart showing a construction process, and FIGS. 2 to 7 show states of a cross-sectional repair structure in each construction process.

  First, the deteriorated concrete in the peeled portion A (FIG. 2) of the existing floor slab C that requires cross-sectional repair is removed with a water jet or the like to perform surface treatment. At that time, in order to prevent the recurrence of the peeling due to the deterioration of the deteriorated concrete, it is preferable to remove until the rebar 1 is exposed as shown in FIG. (S1).

After the surface treatment is performed, mortar is sprayed. In this embodiment, spraying is performed twice (S2).
The first spraying performs the basic mortar 2 up to the surface of the reinforcing bar 1 (FIG. 4).
Thereafter, the steel bars 1 are pushed and filled with a trowel or the like so that there is no portion where the mortar is not filled in the corners or the back side of the reinforcing bars 1 (FIG. 5).
Next, the surface mortar 3 is sprayed to a predetermined thickness for the second time (FIG. 6). Polymer cement mortar (PCM) was used for the mortar.
Depending on the thickness of the mortar required for cross-sectional repair, each spraying step can be further divided into a plurality of times.

Next, the fiber sheet 4 is attached to the surface of the surface layer mortar 3 (S3). Finally, the surface of the surface layer mortar 3 whose cross-section is repaired is finished to a smooth and uniform thickness with a trowel or the like. At the time of this finishing, the fiber sheet 4 is brought into contact with the surface whose cross-section has been repaired, and finishing with a trowel or the like is performed in this state. As the fiber sheet 4, a triaxial vinylon fiber sheet 4 as shown in FIGS. 8 and 9 was used. When this finish is performed, as shown in FIGS. 10 to 12, the fiber sheet 4 is buried in the surface of the surface layer mortar 3 as it is smoothed with a scissors (S4, FIG. 7).
Through the above steps, the cross-section of the peeled portion A of the existing floor slab C can be repaired and prevented from peeling off.

  In addition, when the rust of the reinforcing part of the peeled portion A of the existing floor slab C is severe, it is possible to prevent the recurrence of the peeling by cutting the rusted part and connecting a new reinforcing bar.

  The fiber sheet 4 bears the tensile force generated in the cross-sectional repaired part due to the drying shrinkage, and the drying shrinkage crack can be suppressed. Moreover, if the cover part is peeled off again due to rusting of the internal reinforcing bars, it is possible to prevent the peeled concrete from falling.

The flowchart figure which shows the construction procedure of the cross-sectional repair and peeling prevention combined use construction method which concerns on the best form of this invention. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The fragmentary longitudinal cross-sectional view of the existing floor slab lower surface which shows the construction procedure shown in FIG. The top view of the fiber sheet which concerns on the cross-section repair and peeling prevention combined use method shown in FIG. FIG. 9 is a cross-sectional view taken along the line aa in FIG. 8. The bottom view which shows the state before applying the fiber sheet shown in FIG. 8 to an existing floor slab. The bottom view which shows the state which painted the fiber sheet shown in FIG. The longitudinal cross-sectional view of the lower surface layer part of the existing floor slab shown in FIG. The flowchart figure which shows the construction procedure of the conventional cross-section repair and peeling prevention.

Explanation of symbols

A Stripped part C Existing floor slab 1 Reinforcing bar 2 Basic mortar 3 Surface mortar 4 Fiber sheet

Claims (2)

It is a method of cross-section repair and peeling prevention combined use of existing concrete structures from which concrete has peeled,
The concrete of the peeled portion of the existing concrete structure is removed smoothly on its side and upper surface until the entire circumference of the reinforcing bars in two orthogonal directions are exposed and close to the reinforcing bars so as to be parallel to the exposed reinforcing bars. A surface treatment process;
Cutting the rusted portion of the rebar in the stripped portion and coupling the new rebar; and
Spraying process of spraying basic mortar to the surface of the reinforcing bar;
A leveling step in which the basic mortar is attached to all of the reinforcing bars and boiled so as to eliminate voids;
A second spraying step of spraying a surface layer mortar on the surface of the basic mortar leveled by the leveling step;
A coating step of applying a fiber sheet to the surface layer mortar while leveling the surface of the surface layer mortar before curing the surface layer mortar, the fiber sheet having fibers arranged in a lattice pattern, Is a triangle, a triaxial vinylon fiber sheet,
The basic mortar and the surface mortar are polymer cement mortars,
The spraying step and the second spraying step are carried out in a plurality of times according to the thickness of the basic mortar and the surface layer mortar . An existing concrete structure, wherein the cross-section is repaired by the combined method of cross-section repair and peeling prevention according to claim 1.

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