JP3854257B2 - Thickening and peeling prevention combined construction method - Google Patents

Description

  The present invention relates to a method for combined use of preventing thickening and peeling of existing concrete structures such as expressways.

  Road bridge decks are fatigued and deteriorated due to overloaded vehicles and increased traffic volume, and the revision of the Road Structure Ordinance in 1993 increased the size of traffic vehicle regulations. Because of these factors, road bridge decks have to be reinforced. The road bridge deck is divided into a compression side (mainly the road upper surface) and a tension side (mainly the road lower surface and the lower side) according to the load of the vehicle, and the reinforcement needs to be performed on the tension side. As a construction method for performing the reinforcement, there is a bottom surface thickening method in which polymer cement mortar is placed on the bottom surface of an existing concrete structure, and the thickness is increased (thickness is increased by reinforcement for reinforcement when the amount of reinforcing bars is small).

On the other hand, in an existing concrete structure such as an expressway, moisture penetrates from cracks and the like, and as a result of the reinforcing bars rusting and expanding, there is a risk that the surrounding concrete explodes and some of the concrete peels off. For this purpose, there is a peeling prevention method in which a peeling prevention net is bonded to the concrete surface 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 is not applicable to the above-described bottom surface thickening method, and is not applicable to thickening. Further, in order to provide a peeling prevention net in the lower surface thickening method, it is necessary to roughen the thickened finished surface again with a disk sander or the like, and to adhere the peeling prevention net with an epoxy resin. It took time. This procedure is shown in the flowchart of FIG.
This invention is made | formed in view of such a problem, and provides the thickening and peeling prevention combined construction method which can solve the said subject.

To achieve the pre-Symbol object, the present invention provides a thickened, flaking prevention combination method of reinforcing the existing concrete structures, the reinforcement step of Haisuji the rebar tension side of the existing concrete structures, A spraying process of spraying a basic mortar on the tension side, a leveling process in which the basic mortar is attached to all of the reinforcing bars and boiled so as to eliminate voids, and the basic mortar leveled by the leveling process A second spraying step of spraying a surface layer mortar on the surface of the surface layer, and a coating step of applying a fiber sheet to the surface layer mortar while leveling the surface layer of the surface layer mortar before curing the surface layer mortar. Features.
As the fiber sheet, one in which fibers are arranged in a lattice shape can be used.
The lattice can be triangular.
As the mortar, the basic mortar, and the surface layer mortar, polymer cement mortar can be used.
The existing concrete structure is characterized by being reinforced by the above-described method of combined thickening and peeling prevention.

  According to the present invention, it is possible to easily increase the thickness and prevent peeling of an existing floor slab, and it is possible to provide a combined thickening and peeling prevention method that shortens the process and greatly improves the economy.

  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. 5, a combined method for increasing thickness and preventing peeling 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 5 show states of a reinforcing structure in each construction process.

  First, surface treatment such as removal and polishing of the surface of an existing floor slab C that needs reinforcement is performed by water jet or vacuum blasting (S1).

Next, rebar 1 is attached using metal fittings, such as an anchor (S2). After the rebar 1 is attached, mortar is sprayed. In this embodiment, spraying is performed twice (S3).
The first spraying performs the basic mortar 2 up to the surface of the reinforcing bar 1 (FIG. 2).
Thereafter, the steel bars 1 are filled with a trowel or the like so that there are no mortar-filled portions in the corners or the back side of the reinforcing bars 1 (FIG. 3).
Next, the surface mortar 3 is sprayed to a predetermined thickness at the second time (FIG. 4). Polymer cement mortar (PCM) was used for the mortar.
In addition, according to the thickness of the mortar required for reinforcement, each spraying process can be further performed in multiple times.

Next, the fiber sheet 4 is attached to the surface of the surface mortar 3 (S4). Finally, the surface of the thickened surface mortar 3 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 thickened surface, 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. 6 and 7 was used. When this finishing is performed, as shown in FIGS. 8 to 10, the fiber sheet 4 is buried in the surface of the surface mortar 3 as it is leveled with the scissors (S5, FIG. 5).
Through the above steps, the existing floor slab C can be increased in thickness and prevented from peeling off.

  The fiber sheet 4 bears a tensile force generated in the thickened portion due to drying shrinkage, and can suppress drying shrinkage cracks. Further, if the cover part is peeled off 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 thickening and peeling prevention combined 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 top view of the fiber sheet which concerns on the thickening and peeling prevention combined use method shown in FIG. FIG. 7 is a cross-sectional view taken along the line aa in FIG. 6. The bottom view which shows the state before applying the fiber sheet shown in FIG. 6 to an existing floor slab. The bottom view which shows the state which coated 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 lower surface thickness increase and peeling prevention.

Explanation of symbols

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

Claims (5)

Thickening and peeling prevention combined construction method to reinforce existing concrete structures,
A bar arrangement process for arranging reinforcing bars on the tension side of the existing concrete structure;
A spraying step of spraying basic mortar on the tension side;
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 layer of the basic mortar leveled by the leveling step;
And a coating step of applying a fiber sheet to the surface layer mortar while leveling the surface layer of the surface layer mortar before curing the surface layer mortar. The method for combined use of thickening and peeling-off prevention according to claim 1, wherein the fiber sheet is one in which fibers are arranged in a lattice pattern. The thickening / strip prevention combined construction method according to claim 2, wherein the lattice is a triangle. The mortar, thickened, flaking prevention combination method as claimed in any one of claims 1 to 3, wherein the basic mortar and the surface layer mortar is a polymer cement mortar. Existing concrete structures, characterized in that it is reinforced by the thickened-flaking prevention combination method according to claim 1 to 4.

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