JP2009024341A - Fireproof segment and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fireproof segment which can be simply and inexpensively manufactured and which enables tunnel lining to be performed without narrowing the space in a tunnel, and to provide a manufacturing method for the fireproof segment. <P>SOLUTION: This fireproof segment 10 is formed in such a manner that a concrete layer (hereinafter referred to as a fireproof concrete layer 20), which constitutes a surface layer on the side of the in-tunnel space (on the downside in Fig.) and which does not contain calcium hydroxide, is integrated with a normal concrete layer (hereinafter referred to as a non-fireproof concrete layer 30) which constitutes a back portion of the fireproof concrete layer 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fireproof segment that can be constructed without narrowing the space in the tunnel and can be manufactured easily and inexpensively, and a method for manufacturing the same.

  Conventionally, when a fire or the like occurs in a tunnel, it is known that a concrete segment lining the tunnel is deteriorated by the heat. This is because when the calcium hydroxide contained in the concrete reaches a high temperature, it is thermally decomposed into quick lime, and the quick lime absorbs moisture in the concrete and expands, and the expansion pressure causes a crack in the concrete.

On the other hand, for example, Patent Documents 1 to 3 disclose techniques relating to the fireproof segment.
Patent Document 1 discloses a concrete segment in which a refractory concrete layer made of alumina cement is formed so as to be integrated with a segment body.
Patent Document 2 discloses a technique in which a fireproof panel in which a heat insulating material is covered with a metal plate is installed on an inner peripheral surface of a segment installed as a primary lining body of a tunnel.
Patent Document 3 discloses a segment in which a coating layer having a heat insulating property such as a mortar containing a foamed aggregate or a mortar containing a large amount of voids is laminated so as to be integrated.
JP 2002-194996 A JP 2002-201896 A JP 2004-3285 A

  However, in the concrete segment disclosed in Patent Document 1, the setting speed of the alumina cement used for the refractory concrete layer is faster than that of the general-purpose cement (for example, ordinary Portland cement) constituting the main body of the concrete segment. Therefore, in order to set the alumina cement and the general-purpose cement so as to be integrated, it is necessary to add an admixture that delays the setting speed of the alumina cement, which increases the material cost. In addition, the setting speed of alumina cement varies greatly depending on the temperature and humidity, so it is difficult to control the setting speed.

  Moreover, even if a segment having a refractory concrete layer using the above-mentioned alumina cement is constructed, hydrate is transferred from the refractory concrete layer to the concrete of the segment body as it is used for a long time, and the strength of the concrete of the segment body is reduced. Sometimes.

  Furthermore, since alumina cement is expensive compared to other general cements, the construction cost increases. In addition, it is easy to weather in the state of the material, and it is necessary to pay attention to the environment in which it is stored.

  Further, in the concrete segment disclosed in Patent Document 2, in order to install the fireproof panel in the segment, it must be fixed using a fixing tool such as a bolt. If the bolt is broken for some reason, the fireproof panel The panel falls into the space inside the tunnel. Further, the space in the tunnel is reduced due to the thickness of the fireproof panel.

  In addition, in the concrete segment disclosed in Patent Document 3, the strength of the coating layer made of mortar containing foam aggregate or mortar containing a large amount of voids is smaller than that of the concrete of the segment body. The thickness of the segment becomes larger than the thickness of the segment made only of concrete, and the space in the tunnel is also reduced.

  The present invention has been made in view of the above points, and provides a fireproof segment that can be manufactured easily and inexpensively and can cover a tunnel without narrowing the space in the tunnel, and a method for manufacturing the same. Objective.

In order to achieve the above object, the present invention is a segment for tunnel lining having fire resistance,
At least the surface layer inside the tunnel is made of refractory concrete containing no calcium hydroxide (first invention).

According to the refractory segment of the present invention, even if heat is applied to the surface layer inside the tunnel due to a tunnel fire or the like, quick lime is not generated, so there is no expansion due to moisture absorption of the quick lime in the concrete. Damage such as cracks is unlikely to occur.
Further, since the strength of the refractory concrete in the surface layer is not different from that of normal concrete, it is not necessary to increase the segment thickness as compared with the concrete containing calcium hydroxide. For this reason, it is possible to cover the tunnel without narrowing the space in the tunnel.

  A second invention is characterized in that, in the first invention, the refractory concrete is formed so as to be integrated with non-refractory concrete constituting a portion other than the surface layer.

According to the refractory segment of the present invention, even when heat is applied to the segment from the inside of the tunnel due to a fire or the like, the refractory concrete on the surface layer suppresses heat conduction to the non-refractory concrete. Hard to occur.
In addition, the material cost of refractory concrete is higher than that of non-refractory concrete, but the area where refractory concrete is formed in the segment is limited to the surface layer that is targeted for fire resistance, so the entire segment is made of refractory concrete. The material cost can be reduced as compared with the case of configuring.

  According to a third invention, in the first or second invention, the refractory concrete includes cement, water, an aggregate, and an admixture, and includes at least pozzolana as the admixture.

A fourth invention is characterized in that, in the third invention, the weight occupied by the pozzolan is 60 to 80% of the total weight of the cement and the admixture.
According to the refractory segment of the present invention, when the pozzolan is specifically blended in the above ratio, the calcium hydroxide contained in the concrete disappears and the strength necessary for the segment is provided.

According to a fifth invention, in the fourth invention, the pozzolan contains at least silica fume, and a weight occupied by the silica fume in a total weight of the cement and the admixture is 10 to 20%. Features.
According to the fireproof segment of the present invention, by specifically blending silica fume in the above ratio, the initial strength as a segment (compressive strength within one week of material age) satisfies the standard, and the flow required at the time of placing Have sex.

  According to a sixth aspect, in the fifth aspect, the pozzolan includes fly ash together with the silica fume.

  According to a seventh invention, in any one of the third to sixth inventions, the admixture includes at least blast furnace slag together with the pozzolan.

  An eighth invention is characterized in that, in any one of the third to seventh inventions, ordinary Portland cement is used as the cement.

A ninth invention is the invention according to any one of the second to eighth inventions, wherein the thickness of the surface layer is such that when heat is applied to the surface of the surface layer under heating conditions according to a RABT curve, the refractory concrete and the non-refractory concrete It is characterized in that it is set so that the temperature at the boundary surface with the temperature becomes 350 ° C. or lower.
According to the refractory segment of the present invention, the thickness of the surface layer is such that the temperature at the boundary surface between the refractory concrete and the non-refractory concrete is 350 ° C. or less, that is, the non-refractory concrete does not cause a decrease in yield strength. By being set, the thickness of the refractory concrete, which has a high material cost, can be minimized, thereby contributing to the reduction of the manufacturing cost.

A tenth invention is characterized in that, in any one of the first to ninth inventions, the surface concrete layer contains polypropylene.
According to the refractory segment of the present invention, the polypropylene in the surface concrete disappears in the event of a fire, creating a void inside the concrete, and this void becomes a water channel in the concrete. Is avoided and damage due to heat is more unlikely to occur.

  An eleventh aspect of the invention is a method for manufacturing a fire-resistant segment for tunnel lining, in which either a concrete material containing pozzolan or a concrete material containing no pozzolan is a segment type. A concrete placing step for placing the other concrete material so as to be integrated with the placed concrete material after the placed concrete material is solidified after being placed on the frame; and the segment mold A curing and solidifying step of curing and solidifying the two concrete materials placed on the wall for a predetermined time.

According to the method for producing a segment of the present invention, a segment including a concrete layer that does not contain calcium hydroxide and has fire resistance can be easily and inexpensively produced by a pozzolanic reaction.
Moreover, before one concrete material previously placed is solidified, by placing the other concrete material so as to be integrated with the concrete material previously placed, the concrete containing the pozzolan of the surface layer, The concrete which does not contain pozzolanes other than the surface layer can be reliably integrated.

  ADVANTAGE OF THE INVENTION According to this invention, the fireproof segment which can be manufactured simply and cheaply, and can cover a tunnel without narrowing the space in a tunnel, and its manufacturing method can be provided.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of a refractory segment 10 according to the present embodiment.

  As shown in FIG. 1, the refractory segment 10 includes a concrete layer (hereinafter referred to as a refractory concrete layer 20) that does not contain calcium hydroxide and constitutes a surface layer on the tunnel inner space side (lower side in the figure). It is formed so that a normal concrete layer (hereinafter referred to as a non-refractory concrete layer 30) constituting the back portion of the concrete layer 20 is integrated. In addition, in the same figure, the display of the reinforcing bars etc. which are arranged in the fireproof segment 10 is omitted.

  The refractory concrete layer 20 and the non-refractory concrete layer 30 are composed of cement, an admixture, an aggregate, water, and other additives. However, in the refractory concrete layer 20, a pozzolana is blended in the admixture in order to eliminate calcium hydroxide in the cement.

  Here, the reason why the pozzolan is blended in the refractory concrete layer 20 is as follows. That is, cement (for example, ordinary Portland cement) used for concrete constructed by general construction or structure contains calcium hydroxide that causes deterioration of concrete by heating. When pozzolanic is blended with this cement at a predetermined ratio, calcium hydroxide in the cement chemically reacts with pozzolanic to form calcium silicate, and calcium hydroxide disappears. In this way, by adding pozzolan, calcium hydroxide can be easily eliminated, so pozzolan is added to the refractory concrete layer 20.

  The blending ratio of the pozzolan is set so that the weight occupied by the pozzolana is 60 to 80% of the total weight of the cement and the admixture. This is because it is necessary to mix at least 60% by weight or more in order to eliminate calcium hydroxide in the cement (described in Japanese Patent No. 2941269 of the present applicant), and when the blending ratio of pozzolana increases, Although the compressive strength is reduced, if the blending ratio is up to 80% by weight, the necessary compressive strength as a segment is obtained (development of low alkaline cement considering pozzolanic reaction for support system in HLW repository construction, M. Nakayama, K. Iriya, A. Fujishima, M. Mihara, K. Hatanaka, Y. Kurihara and M. Yui, Proceedings of Materials Research Society Symposium, Vol. 932, p. 159-166 (2006)).

  As the pozzolan, a mixture of silica fume, which is a by-product when producing a silicon alloy, and fly ash, which is fine coal ash, is used.

  The mixing ratio of the silica fume is set so that the weight of the silica fume is 10 to 20% of the total weight of the cement and the admixture. This means that if silica fume is blended at least 10% by weight, the initial strength of the concrete segment (compressive strength within one week of age) will satisfy the standard, and 20% to ensure the fluidity required for construction. It is because it cannot mix more than%. Further, the remaining part of the pozzolan excluding silica fume is fly ash.

  In addition, even if these pozzolanic materials are blended with concrete material, the setting speed does not change particularly.

  Moreover, you may use the blast furnace slag which quenched rapidly the noro (slag) produced when manufacturing pig iron in a blast furnace as admixtures other than pozzolana. Specifically, as the blending ratio of such cement and admixture, the weight of ordinary Portland cement is 20, the weight of silica fume is 20, the weight of blast furnace slag is 30, with respect to the total weight of cement and admixture 100, The weight of fly ash can be 30.

  Moreover, it is preferable to add a polypropylene to the refractory concrete layer 20 as an additive. Polypropylene disappears in the concrete in the event of a fire, creating voids in the concrete that become water channels in the concrete, avoiding the expansion of moisture inside the concrete and making the concrete more reliable. Prevent deterioration due to heat.

  In the case where a fire or the like occurs in the tunnel space, the refractory concrete layer 20 is damaged by heat even if the heat is conducted from the surface of the refractory concrete layer 20 to the non-refractory concrete layer 30. The thickness is such that it will not occur.

  Specifically, the thickness of the refractory concrete layer 20 is the temperature at the boundary surface between the refractory concrete layer 20 and the non-refractory concrete layer 30 when heat is applied to the surface of the refractory concrete layer 20 under heating conditions based on the RABT curve. Is set to 350 ° C. or lower. In addition, 350 degrees C or less is the temperature at which concrete does not raise | generate a yield strength fall. The RABT curve is a curve showing a temperature history in a fire resistance performance test defined in “Regulations on road tunnel equipment and operation” in the Federal Republic of Germany.

  FIG. 2 is a graph showing a RABT curve. As shown in FIG. 2, the RABT curve was first heated to 1200 ° C. in proportion to the time in 5 minutes from the start of the test, then maintained at the temperature from the start to 60 minutes, and then from the start to 170 minutes. A temperature history that cools to the temperature at the start of the test is shown.

  Since the test for actually examining the thickness of the refractory concrete layer 20 based on the heating condition by the RABT curve was conducted, the detailed result will be described.

  FIG. 3 is a schematic diagram showing an outline of a test body used in a test for examining the thickness of the refractory concrete layer 20.

  As shown in FIG. 3, a test body having a width of 4700 mm, a depth of 800 mm, and a height of 500 mm simulating a concrete segment was produced. In preparation, a plurality of thermocouples for measuring the temperature inside the test body were installed at a predetermined depth from the heating surface (the lower surface shown in the figure).

FIG. 4 is a table showing the layer structure and material composition of the concrete used for the specimen.
As shown in FIG. 4, three types of test specimens were produced according to the concrete layer structure and material composition. Specimen No. 1 and Specimen No. 2 has a two-layer structure having a refractory concrete layer having a thickness of 50 mm on the heating surface side and a non-refractory concrete layer on the remaining portion having a thickness of 450 mm. On the other hand, the specimen No. 3 has a one-layer structure composed only of refractory concrete. The material composition of the refractory concrete and the non-refractory concrete for the two-layer test specimen is the specimen No. 1 differs only in the presence or absence of blending of polypropylene (indicated as PP fiber in the figure). 2 is not only polypropylene but also other concrete materials. In addition, the specimen No. The material composition of the refractory concrete of No. 3 is the specimen No. 3. The same thing as 2 refractory concrete was used.

  A fire resistance performance test based on the heating condition based on the RABT curve was performed for each of the test specimens as described above, and the temperature history measured by each thermocouple installed at each depth in each test specimen was recorded. Furthermore, the maximum temperature in each temperature history was extracted, and the relationship between the depth from the specimen surface where the temperature history was measured and the extracted maximum temperature was organized.

  FIG. It is the graph which showed the relationship between the depth from the test body surface, and the maximum temperature measured by the depth about each of 1-3. In addition, FIG. It is the table | surface which put together the depth which reaches 350 degreeC from the test body surface about each of 1-3. The depth reaching 350 ° C. is read from FIG.

  As shown in FIG. 5, the three types of test specimens show substantially the same temperature distribution. And any specimen No. If the depth from the surface of 1 to 3 is 50 mm or more, the internal temperature becomes 350 ° C. or less (see FIG. 6). That is, when constructing a segment with the same configuration as that of the present test body, it is possible to prevent a decrease in the proof strength of the non-refractory concrete layer 30 by setting the thickness of the refractory concrete layer 20 to at least 50 mm.

Next, a method for manufacturing the refractory segment 10 will be described.
FIG. 7 is a diagram for explaining a manufacturing process of the refractory segment 10.

  As shown in FIG. 7, the fireproof segment manufacturing method includes a fireproof layer placing step S10 for placing a pozzolan-containing concrete material 22 and a non-fireproof layer placing step S20 for placing a concrete material 32 not containing a pozzolan. And a curing and solidifying step S30 for curing and solidifying the placed concrete.

  In the refractory layer placing step S10, the concrete material 22 containing the pozzolan at a predetermined ratio as described above (becomes the refractory concrete layer 20 after solidification) is placed in a formwork that combines the formwork 40 and the cover formwork 42. Set up. As the formwork 40, the formwork 40 normally used when manufacturing a precast segment can be used. The lid mold frame 42 is a plate material having a curved surface such that when combined with the mold frame 40, the surface facing the bottom surface in the mold frame 40 is separated from the bottom surface in the mold frame 40 by a certain distance. An injection port 44 for injecting a concrete material is formed at the center. Then, the lid mold frame 42 is arranged such that the distance from the bottom surface in the mold frame 40 is the thickness of the refractory concrete layer 20 to be set, and the concrete material 22 is placed.

  In the non-refractory layer placing step S20, when the concrete material 22 placed on the segment mold 40 in the fire-resistant layer placing step S10 is in a semi-consolidated state, the lid form 42 is removed, and the non-refractory concrete is placed. The cover mold 43 having a shape forming the layer 30 is replaced with a concrete material 32 containing no pozzolan (which becomes a non-refractory concrete layer 30 after solidification) so as to be integrated with the upper surface of the concrete material 22. To do.

  In the curing and solidifying step S30, both the concrete materials 22 and 32 placed in the refractory layer placing step S10 and the non-refractory layer placing step S20 are sufficiently cured and solidified integrally. And the refractory segment 10 is produced by releasing the integrated refractory concrete layer 20 and the non-refractory concrete layer 30 from the mold 40 and the lid mold 43.

  Here, a test for examining the relationship between the placement timing interval between the refractory concrete layer 20 and the non-refractory concrete layer 30 (hereinafter referred to as the stacking time) and the bonding strength between the layers was performed, and the result will be described. .

  FIG. 8 is an external view of a test body used in a test for examining the relationship between the stacking time and the bonding strength between layers.

  As shown in FIG. 8, a cylindrical test body having a diameter of 100 mm and a height of 200 mm composed of two layers of a refractory concrete layer 20 having a thickness of 50 mm and a non-refractory concrete layer 30 having a thickness of 150 mm is obtained by stacking time. Six types were produced (stacking time: 0 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes). In addition, for comparison, a non-refractory concrete material not containing pozzolans was used to produce a single-piece test specimen having the same shape and not having a layer structure.

  In addition, the refractory concrete layer 20 and the non-refractory concrete layer 30 have the test body No. A refractory concrete and a non-refractory concrete having the same composition as 1 were used.

  A direct tensile test was performed on each of these specimens. Since the test method is not standardized as a concrete strength test, the direct tensile test was performed by a test method as shown in FIG.

  As shown in FIG. 9, jigs were attached to both end faces of the test specimens with an adhesive, and tensile loads were directly applied to both ends of these test specimens, and the load until the test specimens were broken was measured. And the value which remove | divided the maximum tensile load at this time by the area of the test body end surface was made into tensile strength. In addition, the strength ratio between the two-layer test specimens and the integrally test specimen was determined.

  FIG. 10 shows the results of the direct tensile test. FIG. 10 (a) is a table summarizing the results, and FIG. 10 (b) summarizes the strength ratio between each of the two-layered test specimens and the one-piece test specimen. It is a graph.

  As shown in FIG. 10, it was confirmed that the tensile strength at the boundary between the refractory concrete layer 20 and the non-refractory concrete layer 30 sharply decreases when the stacking time exceeds 120 minutes. Further, it was confirmed that if the stacking time was within 60 minutes, a strength comparable to the split tensile strength of the integrally punched specimen was obtained. That is, when producing a segment with the same structure as this test body, the refractory concrete layer 20 and the non-refractory concrete layer 30 can be integrated by setting the stacking time within 60 minutes. However, if the stacking time becomes too short, refractory concrete and non-refractory concrete are mixed or refractory concrete flows, and the refractory concrete layer 20 as designed may not be formed. It is preferable to place the non-refractory concrete material 32 when the refractory concrete layer 20 is in a semi-consolidated state.

  According to the refractory segment of the present embodiment described above, the refractory concrete layer 20 contains at least pozzolan as an admixture of its constituent materials, so that calcium hydroxide in the concrete is lost by pozzolanic reaction. That is, even if heat is applied to the surface of the refractory concrete layer 20 by a tunnel fire or the like, quick lime is not generated. Hard to occur.

  Moreover, since the strength of the refractory concrete not containing calcium hydroxide in the surface layer does not change from that of normal concrete, the segment thickness does not need to be increased as compared with the case where the refractory concrete layer 20 is not provided. For this reason, it is possible to cover the tunnel without narrowing the space in the tunnel.

  Further, according to the refractory segment of the present embodiment, since the refractory concrete layer 20 is formed so as to be integrated with the non-refractory concrete layer 30, heat is given to the refractory segment 10 from inside the tunnel due to a fire or the like. However, since the refractory concrete layer 20 suppresses heat conduction to the non-refractory concrete layer 30, the non-refractory concrete layer 30 is unlikely to be damaged by heat.

  Moreover, according to the fireproof segment of this embodiment, while the weight occupied by pozzolanes is 60 to 80% of the total weight of the cement and the admixture, the calcium hydroxide contained in the concrete disappears. , With the necessary strength as a segment.

  Further, according to the refractory segment of the present embodiment, at least silica fume is used as a pozzolan, and the weight occupied by the silica fume is 10 to 20% of the total weight of the cement and the admixture. The initial strength (compressive strength within one week of material age) as a segment for tunnel lining satisfies the standard, and it has the fluidity required for placing.

  Further, according to the refractory segment of the present embodiment, the material cost of the concrete of the refractory concrete layer 20 is higher than the concrete of the non-refractory concrete layer 30, but the concrete of the refractory concrete layer 20 is formed in the refractory segment 10. Since the region to be covered is limited to the surface layer intended for fire resistance, the material cost can be reduced as compared with the case where the entire segment is made of fireproof concrete.

  Furthermore, the thickness of the refractory concrete layer 20 is such that when the surface of the refractory concrete layer 20 is heated under the heating conditions based on the RABT curve, the temperature at the boundary surface between the refractory concrete layer 20 and the non-refractory concrete layer 30 is 350 ° C. or less. Thus, that is, by setting the non-refractory concrete layer 30 so as not to cause a decrease in the yield strength, the thickness of the refractory concrete having a high material cost can be minimized, thereby contributing to the reduction of the manufacturing cost.

  Further, according to the method for manufacturing a refractory segment of the present embodiment, in the non-refractory layer placing step S20, when the concrete material 22 containing no pozzolan is in a semi-consolidated state, the concrete material 22 containing pozzolan is in a semi-consolidated state. The refractory concrete layer 20 and the non-refractory concrete layer 30 can be surely integrated by placing them so as to be integrated with the upper surface of the concrete material 22.

It is sectional drawing of the fireproof segment 10 which concerns on this embodiment. It is a graph which shows a RABT curve. It is a schematic diagram which shows the outline | summary of the test body used for the test for examining the thickness of the refractory concrete layer. It is a table | surface which shows the layer structure and material composition of concrete used for the test body. It is the graph which showed the relationship between the depth from a test body surface, and the highest temperature measured by the depth for every test body. Specimen No. It is the table | surface which put together the depth which reaches 350 degreeC from the test body surface about each of 1-4. It is a figure for demonstrating the manufacturing process of a fireproof segment. It is the external view of the test body used for the test for examining the relationship between a stacking time and the joining strength of an interlayer. It is a figure which shows the method of a direct tensile test. The results of the direct tensile test are shown, in which FIG. (A) is a table summarizing the results, and FIG. (B) is a graph summarizing the strength ratios of the two-layered test specimens and the one-piece test specimen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Refractory segment 20 Refractory concrete layer 22, 32 Concrete material 30 Non-refractory concrete layer 40 Mold 42, 43 Lid form 44 Inlet S10 Refractory layer placing process S20 Non-refractory layer placing process S30 Curing solidification process

Claims (11)

A tunnel lining segment with fire resistance,
A refractory segment characterized in that at least the surface layer inside the tunnel is made of refractory concrete containing no calcium hydroxide.   The refractory segment according to claim 1, wherein the refractory concrete is formed so as to be integrated with non-refractory concrete constituting a portion other than the surface layer.   The refractory segment according to claim 1, wherein the refractory concrete includes cement, water, aggregate, and an admixture, and includes at least pozzolanic as the admixture.   The refractory segment according to claim 3, wherein a weight occupied by the pozzolan is 60 to 80% of a total weight of the cement and the admixture. The pozzolan includes at least silica fume,
The refractory segment according to claim 4, wherein the silica fume occupies 10 to 20% of the total weight of the cement and the admixture.   The refractory segment according to claim 5, wherein the pozzolan includes fly ash together with the silica fume.   The refractory segment according to any one of claims 3 to 6, wherein the admixture includes at least blast furnace slag together with the pozzolan.   The fireproof segment according to any one of claims 3 to 7, wherein ordinary Portland cement is used as the cement.   The thickness of the surface layer is set so that the temperature at the boundary surface between the refractory concrete and the non-refractory concrete is 350 ° C. or less when heat is applied to the surface of the surface layer under heating conditions based on the RABT curve. The refractory segment according to any one of claims 2 to 8, wherein the refractory segment is provided.   The fireproof segment according to any one of claims 1 to 9, wherein the surface concrete contains polypropylene. A method for producing a tunnel lining segment having fire resistance,
After poking the concrete material containing pozzolan or the concrete material not containing the pozzolan, after placing one concrete material on a segment formwork, before the concrete material placed is solidified, the other concrete material A concrete placing process for placing the concrete material integrally with the placed concrete material,
A curing and solidifying step of curing and solidifying the two concrete materials placed on the segment mold for a predetermined time.

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