JP4897607B2 - Repair method for slab type track - Google Patents

Description

  In the present invention, a track slab is fixed on a roadbed of a concrete structure with cement asphalt mortar sandwiched, and the cement asphalt mortar is cracked, peeled off, and dropped due to deterioration in a slab type track in which the track rail is held on the track slab. It is related with the repair method in the slab type track | orbit which repairs.

  A structure with an elevated structure constructed of concrete, an underground structure or a bridge as a roadbed, a concrete track slab fixed on the concrete roadbed with cement asphalt mortar, and a track rail connected directly to this track slab. Slab type track is widely adopted.

  FIG. 11 is a perspective view showing a part of the structure of the slab type track. In FIG. 11, reference numeral 10 denotes a concrete roadbed, and cylindrical protrusions 12 protrude from the upper surface of the roadbed 10 at predetermined intervals (for example, intervals of 5 m) along the rail laying direction. Reference numeral 14 denotes a track slab. The semicircular cutout portions 16 formed at the ends of the track slabs 14 are sequentially arranged while being aligned with the protrusions 12. Then, after the position of the track slab 14 is lifted and adjusted with a dedicated instrument, cement asphalt mortar (hereinafter also referred to as CA mortar) is injected and filled between the roadbed 10 and the track slab 14 to form a packed bed 18.

  CA mortar is a mixture of cement, asphalt emulsion, and fine aggregate. The CA mortar is also filled between the protrusion 12 of the roadbed 10 and the notch 16 of the track slab 14. A track rail 20 is fixed to the upper surface of the track slab 14 by fasteners 22. The left and right track rails 20 are fixed to one track slab 14 by eight fasteners 22 each.

  Stretching stress due to temperature change of the track rail 20 is applied to the packed bed 18 via the track slab 14, and external force due to passage of a train or centrifugal force is applied via the track slab 14. For this reason, deterioration / fatigue of the filling layer 18 proceeds. In cold regions, the water that has soaked into the packed bed 18 freezes and thaws, and as a result, the packed bed 18 deteriorates due to repeated repetition, and cracks, peeling, and dropping off from the surrounding exposed portions. For this reason, it is necessary to repair the filling layer 18 in a relatively short period of time.

  Conventionally, a repair method has been proposed in which a deteriorated portion of a filling layer is scraped off and then a polyurethane resin repair material is filled. For example, "Guide for repairing each part of slab track" (May 1, 1998, 2nd edition), Chapter II (Repair of filling layers and protrusions with synthetic resin), edited and published by Railway Research Institute This conventional method is shown in the (Guide).

  However, the repair material used in this method, especially when wet, has poor adhesion between the filling layer remaining between the roadbed and the track slab and the roadbed and track slab, and the repaired filler (hereinafter also referred to as repair filler) There was a problem of jumping out from between the roadbed and the track slab. In particular, when the deteriorated filler is shaved off (removed) from the outside of the track slab, for example, when it is shaved to a depth of about 50 mm, the repaired filler is likely to jump out. This pop-out of the repair filler must be surely prevented.

  For this reason, it is necessary to scrape the packed layer sufficiently deeply (for example, 100 mm or more) including a portion that has not deteriorated. However, since the scraped filler becomes industrial waste, not only the amount of waste processing increases but also the amount of filler used for repair increases, which is not desirable. Further, since the amount of scraping of the packed bed increases, the working time for scraping (removing) becomes longer, and the working efficiency also decreases.

JP2002-129503

  In Patent Document 1, a hole (mortar inlet, air vent) that penetrates the track slab and the filler layer and reaches the roadbed concrete is formed obliquely downward from the side surface of the track slab. A repair method for injecting a functional resin is shown. In this method, the repair material is caused to flow over the entire surface of the filling layer below the track slab, and since the hardened repair material is engaged with the hole, it is considered that it is possible to prevent the repair material from jumping out of the track slab.

  However, in the method shown in this cited document 1, the gap formed under the track slab does not necessarily correspond to the position of the hole, so that the filler cannot be accurately injected into the gap. Further, since the hole is formed in the track slab obliquely downward from the side surface, the strength of the track slab may be reduced, and the hole processing is troublesome.

  The present invention has been made in view of such circumstances, and the adhesiveness of the repair filler to the packed bed, the roadbed, and the driving slab is good, and particularly when the repaired part is wet (when wet), the adhesiveness is also good. Stable adhesion can be obtained without being affected by construction conditions (rainy weather, etc.), so that even if the amount of scraped deteriorated filler is reduced, the repaired filler does not pop out, reducing the amount of scraping. By reducing the amount of industrial waste, the amount of repair filler used is reduced, making it suitable for environmental protection, improving work efficiency, and the track by processing holes in the track slab. An object of the present invention is to provide a repair method that does not cause a decrease in strength of the slab.

  According to the present invention, this object is to provide a method for repairing a slab-type track in which a track slab is fixed to a concrete roadbed with a cement asphalt mortar and a track rail is held on the track slab, and (a) the deteriorated cement asphalt mortar. Is removed from the periphery of the track slab to an appropriate depth in the horizontal direction: (b) The side of the track slab is surrounded by a mold frame through a release sheet so as to close the space from the side surface; (C) An injection port that opens upward is formed between the release sheet and the side surface of the track slab by spreading the release sheet into a notch that opens upward on a surface of the mold that faces the track slab. (D) Mixing an inorganic aggregate with a synthetic resin having radical curability as a base material into the gap from the injection port to harden the base material. A filling material for repair with an agent added is poured, and after filling, a padding plate is inserted into the cutout of the mold from above, and cured and cured. (E) After the curing of the repair filler, the mold and release sheet It is achieved by a repair method for a slab type track characterized by sequentially performing the above steps a to e.

  The radical-curing synthetic resin used as a filling material for repair is rich in fluidity, and the adhesion between the roadbed and the track slab and the cement asphalt mortar packed layer sandwiched between them is very strong when wet. Adhesive strength is also large enough. For this reason, when the deteriorated portion of the filler layer (CA mortar) is scraped (removed) from the surroundings, the repaired filler does not jump out to the outside even if the scraping depth is reduced to reduce the scraping amount.

  In addition, since less scraping is required, the amount of industrial waste is reduced, and the amount of filler used for repair is also reduced. Therefore, it is suitable for environmental protection. Further, since the amount of scraping is small and the filling amount to be repaired is small, it is also suitable for improving work efficiency.

  In this method, the void created by scraping is surrounded by a mold frame from the side via a release sheet, and the release sheet is spread out into a notch that opens upward on the inner surface of the mold (the surface facing the track slab). The repair filler is injected into the gap from the injection port. For this reason, it is not necessary to machine a hole in the track slab, and there is no possibility of incurring strength reduction due to the processing of the track slab.

In Claim 1, following a process (a), the following processes (a-1),
(A-1) A concave portion is formed by cutting the vicinity of the track slab side lower part of the concrete roadbed;
(Claim 2). In this case, since a part of the repair filler flows into the recess and is cured, the mechanical bond strength between the cured filler and the concrete roadbed is increased. For this reason, the adhesive force between the roadbed and the track slab and the filler can be increased, and the mechanical coupling force between the filler and the concave portion can be increased, and the repaired filler can be prevented from popping out more reliably. .

In Claim 1, following a process (a), the following processes (a-2),
(A-2) applying a primer to the inner surface of the gap;
(Claim 3). As a primer used in this case, either a urethane resin, an epoxy resin, or a synthetic resin having radical curability is suitable (claim 10). This primer may be a mixture of cement powder, but a one-component moisture-curing urethane resin that has good adhesion to the filler and good workability is optimal. Thus, by applying the primer before filling the filler, the adhesion strength with the filler is sufficiently increased even when the surface of the roadbed and the track slab that form the gap leaks due to rainwater or night dew. be able to.

  For this reason, for example, when it starts to rain during or after scraping off old deteriorated cement asphalt mortar in step (a), or when it rains on the scheduled date of inflow of filler after the mortar scraping work day It becomes possible to implement as scheduled without changing the inflow work day of the filler. In other words, the repair filler used in the present invention basically has a high adhesive strength when wet with the roadbed and track slab, but the adhesive strength decreases to some extent when rainwater adheres to the adhesive surface. There is no choice but to do. However, by applying a primer, this decrease in adhesive strength can be sufficiently suppressed.

Further, in claim 1, following the step (a), the following steps:
(A-1) A concave portion is formed by cutting the vicinity of the track slab side lower part of the concrete roadbed;
(A-2 ′) applying a primer to the inner surface of the gap and the recess;
(Claim 4). In this case, the primer increases the bonding strength between the filler and the roadbed and the track slab, and strengthens the physical and mechanical engagement between the recess formed in the roadbed and the filler, thereby Jumping out can be prevented more reliably.

  As the synthetic resin having radical curability in the step (d) in claim 1, a synthetic resin mainly composed of polyester acrylate is suitable (claim 5). More specifically, the polyester acrylate is most preferably a solvent-free vinyl ester resin or modified MMA (methyl methacrylate). This is because the adhesive strength is strong and the durability is improved. Only a polyester acrylate may be used as a synthetic resin containing polyester acrylate as a main component (claim 6).

  The repair filler preferably includes a radical curable synthetic resin and an inorganic aggregate in a weight ratio of 100: 50 to 200 (Claim 7). In this case, the compression strength and the spring characteristics are suitable for satisfying predetermined conditions, and the durability is excellent and the cost is relatively low. The inorganic aggregate is preferably cinnabar. This is because cinnabar does not inhibit the radical curing reaction and is easily available and inexpensive. As the inorganic aggregate, natural mineral products such as bauxite, fired products such as porcelain and ceramics, crushed shells and the like, blast furnace slug, etc. can be used instead of or mixed with cinnabar.

  The number of inlets provided in the mold is preferably 3 to 4 with respect to one side of one track slab. For example, when each rail is fastened to the track slab with six or more fastening devices, the inlets provided near the second fastening device from both ends in the longitudinal direction of the track slab, and 1 to 2 provided therebetween Two inlets are provided (claim 8). In this way, it has been found that the filler is smoothly and uniformly injected under the track slab.

  If the viscosity of the filling material for repair is 2000 mPa · s or less at 20 ° C., the fluidity at the time of pouring is good and it flows smoothly under the slab. Moreover, if the pot life at this time, that is, the time until the start of the curing and the workable time is 10 minutes or more, it is convenient for the construction (claim 9).

  Before enclosing the outer periphery of the track slab with a mold, the void obtained by scraping (removing) the deteriorated portion of the packed bed may be heated by a burner such as a gas burner to perform dehumidification treatment in the void. To further improve the adhesive strength between the filling material for repairing and the roadbed, track slab and filling layer (CA mortar) in the gap, and further promoting the hardening of the filling material for repairing by heating in the gap. Because you can.

  FIG. 1 is a plan view showing the concept of the repair method, FIG. 2 is a plan view showing an example of scraping (removing) a deteriorated packed bed, FIG. 3 is a diagram showing an example of scraping work, and FIGS. FIG. 5 is an explanatory view of the arrangement of the mold and the filling process of the repair filler, and FIGS. 5A to 5B are explanatory views of the repair liquid curing process. FIG. 6 is a work process diagram.

  In FIG. 1, the same parts as those in FIG. Since the deterioration of the filling layer 18 made of the hardened CA mortar proceeds from the outer periphery, the deteriorated filler is scraped from the outside of the track slab 14. In FIG. 1, the hatched portion 32 is the removal range of the deteriorated filler.

  The hatched portion in FIG. 2A indicates the basic removal range 32A, and the hatched portion in FIG. 2B indicates the partial removal range 32B. The removal range 32 (32A, 32B) is deep near the four corners of the track slab 14 and shallow outside the corner. The deteriorated filler is scraped (removed) as shown in FIG. 3 (step S100 in FIG. 6). FIG. 3 shows a state in which the worker scrapes off the filling layer 18 from the outside (chipping) using a vibration type shaving machine (sharpening machine) having a cutting bit attached to the tip.

  The amount of shaving (the amount of chipping) is determined according to the on-site deterioration status. FIG. 2A shows a case where a normal depth (100 mm) is cut along the side surface, and a portion near the corner is cut deeper. In FIG. 2B, the vicinity of the four corners is cut to a depth of about 50 mm, which is shallower than usual, and the side surface with little deterioration is cut to a depth of about 10 to 50 mm. The void 34 (see A in FIG. 4) formed after scraping and removing the deteriorated filler (deteriorated CA mortar) serves as an injection portion for the repair filler.

  Next, this space | gap (injection part) 34 is cleaned, and it is made to dry using a gas burner (step S102). Then, the mold 36 is fixed to the side surface of the track slab 14 (step S104). Prior to the installation of the mold 36, a curing gum tape 38 is affixed to the side surface of the track slab 14 to prevent a repair filler to be described later from adhering thereto. The formwork 36 is made of two wood plates 36A and 36B which are stacked and adhered (see FIG. 4A), and the inner plate 36B is cut out at three locations as shown in FIG. The notch 40 becomes an injection port 48 described later.

  The track rail 20 is fastened by six or more, preferably eight fasteners 22 (see FIG. 11) within the length range of the track slab 14. In this case, the notches 40 are formed at both ends of the track slab 14. It is preferable to provide one or two places near the second fastener 22 and between these two fasteners 22. In the embodiment of FIG. 1, three notches 40 are provided for the mold 36 on one side. The mold 36 is fixed so as to be in close contact with the side surface of the track slab 14 by a jig (not shown) fixed to the track slab 14 or the roadbed 10 with the release sheet 42 interposed therebetween. The release sheet 42 is a polyethylene sheet, for example, and prevents the repair filler 50 described later from adhering to the mold 36.

  A urethane sponge 44 is attached to the lower edge of the mold 36, and by installing the mold 36, the urethane sponge 44 strongly presses the release sheet 42 against the upper surface of the roadbed 10 and prevents the repair filler 50 from leaking out. It is out. The mold 36 is installed so that its inner surface is in close contact with the side surface of the track slab 14. Further, a separation plate 46 (e.g., elastite (trade name)) is provided so that the repair filler 50 to be injected flows into the gap between the track slabs 14 adjacent in the longitudinal direction of the rail 20 and the track slabs 14 are not fixed to each other (FIG. 1). )

  In this way, while the mold 36 is installed, the vinyl ester resin, its curing agent, and aggregate are kneaded and stirred in order to make the filler 50 for repair (step S106). As the vinyl ester resin, for example, “Allen Lock S” (trade name) sold by the applicant is suitable. In this case, “Parkadox CH-50L” (trade name) sold by the applicant is suitable as the curing agent. No. 8 is suitable as an aggregate. These are preferably in a weight ratio such that the mixing ratio of the vinyl ester resin, the curing agent, and the aggregate is about 100: 3: 100. In this case, the repair filler 50 which is a kneaded product is cured at 20 ° C. in 10 to 15 minutes. Taking this curing time (potential time) into consideration, resin preparation and installation of the mold 36 are performed in parallel.

  On the other hand, in the notch 40 of the mold 36, an injection port 48 that opens upward is formed between the release sheet 42 and the track slab 14 by lifting and releasing the release sheet 42 outward (FIG. 4). (See (B)). Thus, the repair filler 50 previously or concurrently kneaded as described above is injected into the injection port 48 opened upward (step S108). At this time, the repair filler 50 is guided to the gap 34 while the flow direction is guided by the release sheet 42 near the injection port 48. Further, it is confirmed that the repair filler 50 is injected from the injection port 48 over the entire outer periphery of the track slab 14. 4 (A) and 4 (B), 50 indicates the injected uncured repair filler.

  After confirming that the repair filler 50 has flowed into the gap 34 over the entire circumference of the track slab 14, the filling plate 52 is buried in the injection port 48 from the outside of the release sheet 42 (see FIG. 5A). Step S110). The buried plate 52 is inserted from above into the notch 40 of the mold 36 to smooth the inner surface of the mold 36 (the surface facing the side surface of the track slab 14). In this state, the process waits for the repair filler 50 to harden (step S112). In FIG. 5A, 50A shows a state in which the cured repair filler 50 fills the gap 34 (see FIG. 4A). The cured repair filler 50A fills the voids 32, 32A, and 32B indicated by hatching in FIGS. 1, 2A, and 2B. Waiting for the repair filler 50 to harden, the mold 36 is removed (step S114), and the surroundings are cleaned (step S116).

  FIG. 7 is a work process diagram of another embodiment of the present invention. In this embodiment, the following step, that is, a step (S103) of applying a primer to the inner surface of the gap (injection portion) 34 with a brush or the like is added between steps S102 and S104 in the first embodiment.

  As a primer used here, a urethane resin, an epoxy resin, a synthetic resin having radical curability, or a mixture of this with cement powder is suitable. In this case, the repair filler is the same as that used in Example 1, that is, the vinyl ester resin, its curing agent and aggregate are kneaded and stirred. The following steps S104 to S116 are the same as those in the first embodiment.

  According to the second embodiment, since the primer is preliminarily applied to the contact surface of the repair filler 50A, water adheres to the inner surface of the gap (injection portion) 34 due to rain or condensation after the filler is injected. However, since the water applied to the primer applied to the concrete roadbed 10 and the track slab 14 is pushed away by the repair filler 50A having a high specific gravity and integrated with the primer, the inner surfaces of the repair filler 50A and the gap 34, that is, The bond strength between the concrete roadbed 10 and the track slab 14 does not decrease. For this reason, there is no possibility that the repaired filler will jump out.

  FIG. 8 is a partially broken plan view for explaining another embodiment of the present invention, FIG. 9 is a diagram showing a construction method at the cross-sectional position of the IX-IX line, and FIG. 10 is a work process diagram. In this embodiment, the next step after the step S100 in the first embodiment, that is, the step S101 for forming the recess 60 by cutting the vicinity of the lower side of the side surface of the track slab of the concrete roadbed, and the next step after the step S102, A step (S103A) of applying a primer to the inner surface of the void (injection portion) 34 and the concave portion 60 is added.

  In step S101, as shown in FIG. 3, the recess 60 is formed on the surface of the roadbed 10 using a vibration type shaving machine having a cutting bit attached to the tip, following the shaving operation (S100) of the deteriorated CA mortar (filled layer) 18. It is formed by shaving. As shown in FIG. 8, three recesses 60 are provided near the lower portions of the left and right side surfaces of the track slab 14. The number of the recesses 60 may be larger, and may be provided, for example, at four locations on the left and right sides.

  In step S102, the shavings remaining on the inner surface of the gap (injection portion) 34 and the recess 60 are cleaned and dried. In step S103A, a primer is applied to the inner surface of the injection portion 34 and the recess 60. The primer used here is a urethane resin, an epoxy resin, or a synthetic resin having radical curability as in Example 2, or a mixture of this with cement powder. The following steps S104 to S116 are the same as those in the first and second embodiments.

  That is, as shown in FIG. 9, a curing gum tape 38, a release sheet 42, a mold 36, and the like are provided, and the repair filler 50 is injected from an injection port 48 (not shown) (see FIG. 4B). The repair filler 50 is injected into the gap 34 and the recess 60 and cured. After the repair filler 50 is cured, the mold 36 and the like are removed.

  According to the third embodiment, since the repair filler 50 is injected after the primer is applied to the gap 34 and the recess 60, the construction for one day is finished with the primer applied, and the repair filler 50 is repaired at a later date. Even when it is raining when rain is poured or rainwater or condensation is attached to the gap 34 or the recess 60, the repair filler 50 is bonded to the gap 34 or the recess 60 with a strong bonding force. The cured repair filler 50 is mechanically engaged with the recess 60. For this reason, the hardened filling material 50 for repair is held in the gap 34 more strongly than in the first and second embodiments, and is more difficult to jump out.

Experimental example 1

Next, the effect of increasing the adhesive force by using a primer when the adhesive surface is wet will be described. Repairing fillers were filled on the concrete plate in various wet states, and the adhesion strength was measured. The following four types of specimens were prepared according to the difference in the dry state (wet state) of the surface.
a. The surface is dry b. The surface is wet but no water is collected c. Surface with water floating d. About 10mm of water has accumulated on the surface

  The repair filler used here is, for example, a mixture of polyester acrylate, its curing agent, and inorganic aggregate in the mixing ratio shown in the first embodiment.

  Table 1 shows an actual measurement example of the tensile strength when no primer is used and no concave portion is formed on the concrete surface (corresponding to Example 1). In the destroyed state, the repair filler does not peel off from the surface due to the destruction of the base material with the concrete in the dry state a, but in the wet state (b to d), since the water has soaked into the concrete surface, It has become. About the fall of intensity | strength, the adhesive strength of about 85 to 80% is hold | maintained in the state of b and c compared with a of a dry state. In the state d, it is replaced with water and adheres to the ground, but the adhesion is maintained at about 55%.

Experimental example 2

  Next, in Experimental Example 1, adhesion strength was measured when a primer was applied to the surface of a concrete plate and then a repair filler was filled. That is, the primer was applied on the concrete plate in various wet states, and the adhesion strength was measured after curing.

  In the experiment of Table 2, the concrete surface was applied with a primer in a wet state. At this time, the adhesion strength was small, and in particular, there was no merit with the case where the repair filler was directly applied without the primer. Therefore, it was decided to examine the adhesion when the primer was applied in a dry state and the repair filler was filled in a wet state.

  Various primers were applied to the concrete surface in a dry state, and after hardening, the filler was filled with 10 mm of water, and the adhesion strength was measured. Table 3 shows the results.

  Based on the above results, the primer has the advantage that if there is no rain during the CA mortar chipping work in advance, the primer can be applied to ensure sufficient adhesion to the ground even if the concrete surface is wet due to rain on the day. It seems possible. As the primer in this case, a special urethane primer that exhibits the strongest strength due to ground breaking is optimal.

Plan view showing gap depth and formwork installation Plan view showing the state of scraping the deteriorated packed bed Diagram showing an example of scraping work of a deteriorated packed bed Explanatory drawing of mold placement and repair filler injection process Explanatory drawing of curing process of repair liquid Work process diagram Working process diagram of Example 2 The partial cross section top view which shows the position of the recessed part of Example 3 Explanatory drawing of the formwork at the IX-IX line position in FIG. Working process diagram of Example 3 Partial cross-sectional perspective view showing structure of slab type track

Explanation of symbols

10 Roadbed 14 Track slab 18 Packing layer (cement asphalt mortar)
20 Track rail 22 Fastener 32 (32A, 32B) Deteriorated filler removal range 34 Gap 36 Formwork 40 Notch 42 Release sheet 48 Inlet 50 Repair filler 50A Hardened repair filler 52 Filling plate 60 Recessed

Claims (10)

In the repair method in the slab type track where the track slab is fixed by sandwiching cement asphalt mortar on the concrete roadbed, and the track rail is held on the track slab,
(A) A void is formed by removing the deteriorated cement asphalt mortar from the periphery of the track slab to an appropriate depth in the horizontal direction:
(B) Surrounding the side of the track slab with a mold through a release sheet so as to close the gap from the side;
(C) An injection port that opens upward is formed between the release sheet and the side surface of the track slab by spreading the release sheet into a notch that opens upward on a surface of the mold that faces the track slab. Do;
(D) A filling material for repair in which an inorganic aggregate is mixed with a synthetic resin having radical curability as a base material and a curing agent for the base material is added is injected into the gap from the injection port. Insert the embedding board into the cutout of the frame from above, cure and cure,
(E) The mold and the release sheet are removed after the repair filler is cured.
The repair method in the slab type track | truck characterized by performing the process of the above processes ae sequentially. Following the step (a) of claim 1, the following step (a-1),
(A-1) A concave portion is formed by cutting the vicinity of the track slab side lower part of the concrete roadbed;
Repair method in slab type track that adds. Following the step (a) of claim 1, the following step (a-2),
(A-2) applying a primer to the inner surface of the gap;
Repair method in slab type track that adds. Following the step (a) of claim 1, the following steps (a-1) and (a-2 '):
(A-1) A concave portion is formed by cutting the vicinity of the track slab side lower part of the concrete roadbed;
(A-2 ′) applying a primer to the inner surface of the gap and the recess;
Repair method in slab type track that adds.   The method for repairing a slab type track according to claim 1, wherein the synthetic resin having radical curability in the step (d) is a synthetic resin mainly composed of polyester acrylate.   The repair filler used in the step (d) of claim 1 is a repair method in a slab type track in which polyester acrylate, its curing agent, and inorganic aggregate are kneaded.   2. The repair method for a slab track according to claim 1, wherein the repair filler includes a radical curable synthetic resin and an inorganic aggregate in a weight ratio of 100: 50 to 200.   The pair of track rails are fastened to each track slab with at least six fasteners, and the formwork used in step (b) of claim 1 is provided near the second fastener from both ends of the track slab. The repair method in the slab type | formula track | orbit of Claim 1 which has two injection ports and 1-2 injection ports provided among these.   The repair method for a slab type track according to claim 1, wherein the repair filler has a viscosity of 2000 mPa · s or less at 20 ° C and a pot life of 10 minutes or more.   The repair method for a slab type track according to claim 3 or 4, wherein the primer is one of a urethane resin, an epoxy resin, and a synthetic resin having radical curability.

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