NZ600890A - Joining method of concrete structure - Google Patents

Abstract

Disclosed is a joining method of a concrete structure, comprising steps of: laying a plurality of concrete structures, each having a cylindrical or U-shaped cross-section, separately from each other only by a predetermined dimension; installing a backup material made of a non-polar substance at a portion separated from the inner surface of the concrete structure; and pouring an adhesive having stretch capacity of 100 to 250 per cent and density of 0.8 to 1.0 g/cm3 into a space between the surface of the backup material and the inner surface of the concrete structure so as to form a joint portion. Also disclosed is a method of fixing or repairing existing pipes, such as sewer or draining pipes; with the same process.

Description

COMPLETE SPECIFICATION JOINING METHOD OF CONCRETE STRUCTURE I/We, Asahi te Works Co., Ltd., a body corporate organised under the laws of Japan of 12, Tsukiji, Chuo-ku, Tokyo, 104-0045, JAPAN hereby declare the invention, for which I/we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly bed in and by the following statement:- Total Fee Paid: NZ$250.00 – by Direct Debit (as per covering letter) 503629008_1/6858 ED at IPONZ on 25 September 2012 ED at IPONZ on 25 September 2012 Technical Problem [0004} In the method of pulling the rubber mounted on the projecting portion for fitting provided on the end portion of the concrete product by using the pulling means such as the above—described ckle or the like and fitting it in the recess portion of the adjoining concrete product or the method of embedding the arrow—shaped portions of the band—shaped rubber member having the arrow shapes on the both sides in the groove portion for fitting provided in the concrete t, the concrete products can be joined while the mance is ensured in laying the te products, but there iseaproblem that handling after laying is not possible.

In the method of lining by the concrete cast in place in d construction, the adjoining concrete products are y joined, thus there is a problem that unequal settling or ground displacement at an earthquake after that cannot be handled.

In addition, there is a problem that when a shift or a crack occurs in the existing concrete structure as described above,sincetheflexiblejointisextremelyexpensive,arepair cost can be huge with the method of mounting the flexible joints ED at IPONZ on 25 September 2012 ED at IPONZ on 25 September 2012 .Wwwvmmww earthquake, the on portion can follow it and deform to ensure continuity and water tightness. That is, quake resistance, continuity, and water tightness can be given inexpensively and easily to a water l such as a sewage, a passage and the like using a concrete structure having a cylindrical or U—shaped cross—section.

A preferable thickness of an adhesive layer that can ensure continuity and water tightness by such an adhesive, that is, a preferable depth of a space between the surface of the backuplnaterial and the inner surface of the concrete structure is 0.75 to 1 . 25 times of a separation width between the concrete structures.

Alnode for preferably positioning the backup al is arrangement of an outer backup material outside the backup material.

Moreover, another joining method of concrete structure according to the present invention is characterized in that, in an existing te structure having a cylindrical or U—shaped section, a recess groove is formed.in the whole periphery of the inner surface of the concrete structure, a backup al of a non—polar substance is installed in a .m-mmmw i portion in this recess groove separated.fron1the inner surface of the g concrete ure, and an ve having stretch capacity of 100 to 250% and density of 0.8 to 1.0 g/cm3 is poured into a space between the surface of the backup material and the inner surface of the te structure so as to form a joint portion.

With the above method, too, the most important effect of theabove—describedpresentinvention,thatis,theeffectthat the adhesive does not drip down during construction and the construction performance is excellent, the effect that even in occurrence of unequal settling or ground displacement at an earthquake, the adhesion portion s it and deforms to ensurecontinuityandwatertightness,andtheeffectthatquake resistance, continuity, and water tightness can be given inexpensively and easily to the concrete structure can be obtained.

One of preferred embodiments of such joining method is formation of the existing concrete structure by laying a pluralitytxfconcreteproductshavingaacylindricalcntU—shaped cross—section.

Moreover, another one of the preferred embodiments of such joining method is formation of the recess groove in the inner surface<xfa joint portionloetween.the adjoining concrete products. With such embodiment, by applying the present invention to the joint portion of the ng structure in which a plurality of concrete structures are adjacently laid, quake resistance, continuity, and water tightness can.be given to the ng ure when necessary without shutting off a traffic network.

Moreover, as still another one of the preferred embodiments of such joining method is formation of the recess groove in a broken spot on the inner surface of the concrete structure. With such embodiment, the broken spot can be repairedwhennecessarywithoutshuttingoffaatrafficnetwork, and quake resistance, continuity, and water tightness can be given to the existing structure.

Advantage of the Invention ing to the present invention, quake ance, continuity, and water tightness can be given inexpensively and easily to a concrete structure having a cylindrical or U—shaped cross—section.

Brief Description of Drawings Fig. l is a diagram illustrating an installed mode of a concrete structure according to a first embodiment of the present invention.

Fig. 2 is a center udinal sectional View illustratingeastructureformedkn/usingtheconcretestructure according to the embodiment.

Fig. 3 is a sectional View illustrating the concrete structure according to the embodiment.

Fig. 4 is an A—A sectional View in Fig. 2.

Fig. 5 is a diagram for explaining an installation mode of a joint n according to the ment.

Fig. 6 is a 8-8 sectional View in Fig. 4.

Fig. 7 is a sectional View rating a concrete structure ing to a second embodiment of the present ion.

Fig. 8 is a center longitudinal sectional View illustrating a joint portion according to the embodiment.

Fig. 9 is a diagram for explaining an installation mode of the joint portion according to the embodiment.

Fig. 10 is a diagram for explaining an installation.mode of the joint portion according to the embodiment.

Fig. ll is a diagram for explaining an installation mode of the joint portion according to the embodiment.

Fig. 12 is a C~C sectional view in Fig. 8.

Fig. 13 is a diagram illustrating a broken portion of a .mwuwwmwm te structure according to a third ment of the present invention.

Fig. 14 is a diagranlfor explaining an lation mode i of a 3 joint portion according to the embodiment. l Fig. 15 is a center udinal sectional View illustrating the joint portion according to the embodiment.

Fig. 16 is a diagram illustrating an installation mode of a concrete structure according to another embodiment of the t invention.

Fig. 17 is a sectional View illustrating a joint portion according to the embodiment.

Description of Embodiments A first ment of the present invention will be described below by referring to Figs. 1 to 6.

Ajoiningnethodofeaconcretestructureaccordingtothis embodiment is used when a new box culvert 1 is installed between existing box culverts 1’ in a concrete structure having a square cylindrical cross—section or more specifically, in an underground structure such as a sewage or the like formed by connecting a plurality of box culverts l which are concrete products, as illustrated in Figs. 1 and 2. The new box t l is laid separately from the adjacent existing box culverts 1’ only by a tive predetermined separation width w and joined to the existing box culverts 1’ through joint portions As illustrated in Fig. 3, the box culvert 1 has a pair of side plates 12, a bottom plate 11 continuing to the pair of side plate 12, and a top plate 13 positioned opposite to the tplate 11 in this embodiment and.has a square cylindrical shapehaving51so—calledrectangularcross-sectionwithinwhich aninternalspamslsenclosedbythesesideplatesl2,thebottom plate 11, and the top plate 13 is built in and has joint surfaces la on the both ends in the longitudinal direction so as to construct an underground structure by joining the plurality of the joint surfaces 1a. The joint e 1a has a rectangular outer peripheral shape and a substantially rectangular inner peripheral shape and forms a square ringed shape. In this embodiment, as illustrated, the box culvertilwhich.is a square cylindrical concrete product is described, but it is needless to say that the t invention may be applied to configure a three-face Water channel by a concrete product having a U-shaped cross—section formed of a pair of side plates and a bottom plate and having the upper side open.

WWW—m WW Here, a method of joining the box culverts 1 which are “Wu/1,1.» concrete products according to the present invention is a joiningnethodofconcreteproductbyjoiningthejointsurfaces la of the box culverts 1, each having the joint surface la on opposing both ends by a joint portion 2 formed by using an adhesive 21. The method of g this joint portion 2 will be bed below in detail together with the description of the configuration of each part.

As described above and also illustrated in Figs. 4 and 6, the joint portion 2 is formed between the adjoining box ts l and formed by disposing an outer backup material 23, a backup seal material 22 formed.of alionwpolar substance which is an inner backup material, and an adhesive 21 from the outer surface side to the inner surface side of the box culvert 1. e detail, as illustrated in Figs. 4 andéL the outer backup material 23 is disposed in a region from a plane connecting the outer surfaces of the adjoining box culverts l sitionseparatedoutsideknzapredetermineddistancefrom the inner surface of the box culvert 1. Moreover, this outer backup material 23 has a function of positioning an end edge on the outside of the backup seal material 22. In this embodiment, this outer backup material 23 is disposed between the adjoining box culvertsl.and then, the backup seal.material 22 is disposed on the inner side thereof. This outer backup material 23 does not arily have to be provided.

As described above and also illustrated in Figs. 4 and 6, the backup seal material 22 is disposed inside the outer backup al 23 and is a ring—shaped member having a substantially equal thickness dimension over the whole region and is formed of a non-polar nce. The adhesive 21 for joining the box culverts l is poured into a space 25 between the inner surface of this backup seal material 22 and a plane connecting the inner surfaces of the box culverts 1. A depth d of this space 25, that is, a distance from the inner surface of the backup seal material 22 to the plane connecting the inner surfaces of the box culverts l is set to 0.75 to 1.25 times of the separation width w.

As described above and also illustrated in Figs. 4 and 6, the adhesive 21 is poured into the inner side of the backup seal al 22 and has a function of g the adjoining box culverts l sandwiching this adhesive 21 between them. That is, this adhesive 21 is disposed at a position faced with the internalspacecfiftheboxculvertlfl Here,thestretchcapacity mmvowwtnwk of this adhesive 21 is 100 to 250% and the y is 0.8 to 1.0 g/cm3.

That is, when the adjoining box culverts l are to be joined together, first, the outer backup material 23 is disposed in the space between the box culverts l as illustrated in Fig. 5, and the backup seal material 22 is disposed in the inner side thereof. Moreover, as illustrated in Fig. 6, a procedure of pouring the ve 21 into the inner side of this backup seal al 22 and waiting for the adhesive 21 to be solidified is med. When.the adhesive 21 is1x>be poured, though not shown, masking is performed by aInethod of attaching a masking tape or the like on a portion adjacent to the space 23 on the inner surface of the box culvert l and the masking is removed after the adhesive 21 is solidified.by alnethod of removing the g tape or the like. In the case of unequal settling or ground displacement at an earthquake after the water l is formed, this layer in which the adhesive 21 is provided is deformed, and continuity and water tightness between the adjoining box culverts l are maintained.

As illustrated as above, according to the joininglnethod according to this embodiment, even in occurrence of unequal settling or ground displacement at an earthquake and relative positions of the box culverts l and 1’ are changed with that, the adhesicuiportion by the adhesive 21 follows it and deforms, and the continuity and water tightness can be ensured. That is, quake resistance, continuity, and water tightness can be given inexpensively and easily to a structure such as a water channel including a sewage, a passage and the like using a teproductrepresentedby1flmeboxcmlverts].and]J having a square cylindrical cross—section.

Moreover, according to this joining method, since a primer is not needed, reduction of the number of man—hour and a construction period can be realized.

Furthermore, according to this construction , by replacing one of the box culverts l constituting the structure as necessary and forming the joint n 2 on the both sides of this box culvert l, quake resistance, continuity, and water tightness can be given to a structure when necessary.

Subsequently, a second embodiment of the t invention will be described below by referring to Figs. 7 to The joining method of a concrete ure according to this embodiment is performed for a joint portion between existing adjoining box culverts Al in an underground structure such as sewage formed by connecting a plurality of the box culverts Al which are concrete structures, each having a square cylindrical cross—section.

The box culvert Al has a configuration substantially similar to the box t 1 according to the above—described first embodiment. That is, as illustrated in Fig. 7, the box culvert Al has a pair of side plates A12, a bottom plate All continuing to the pair of side plates A12, and a top plate A13 oppositely positioned to the bottom plate All and has a square cylindrical form having a so-called rectangular cross—section incorporating an internal space Als enclosed by the side plates A12, the bottom plate All, and the top plate A13. er, the box culvert Al has joint surfaces Ala on the both ends in the longitudinal direction, and an underground ure is constructed by connecting the plurality of the box ts Al through joining them on joint surfaces Ala. The joint surface Ala has a rectangular outer eral shape and also a substantially rectangular inner peripheral shape and has a square ringed shape. In this embodiment, at a portion faced with the internal space A15 in the joint surfaces Ala, a cutout Alt as illustrated.in Figs. 10 and 12i13provided.over the whole periphery. Though the box culvert A1 which is a square cylindrical concrete product as illustrated is described in this embodiment, it is needless to say that the t ion may be applied to a three—face water l formed of a concrete product having a U—shaped cross—section formed ofthepairofsideplatesAlZandthekmttomplateAllandrmving the upper side open. The “square cylindrical cross~section” is a concept including a form having an inner surface of the bottom plate All swollen in an arc shape on a sectional View.

Here, a joining method of the box culvert A1 which is a concreteproductaccordingtx>thepresentinventionisaijoining method of a concrete product of g the joint portion A2 formed by using an adhesive A21 between the joint surfaces Ala of the box culverts A1, each having the joint surfaces Ala on thebothopposingends,andjoiningthem. Thenethmjofforming this joint portion A2 will be described below in detail with the description of the configuration of each part.

As described above and also illustrated in Fig. 12, the joint portion A2 is formed between the cutouts Alt of the adjoining box ts Al, and a backup seal material A22 formed of a non—polar substance which is a backup material and the “MlW-lwlwmhxmabyuuu.xu adhesiveA21arecfisposed,respectively,frmntheoutersurface m side to the inner surface side of the box culvert Al as illustrated in Figs. 8 and 12. Here, the cutout Alt is formed by cutting away the existing box culvert A1 by using a concrete cutter or the like. That is, a distance w2 between the side faces of the ng cutouts Alt of the ing box culverts Al as illustrated in Fig. 10 is larger than the distance w20 between the existing box culverts A1 as illustrated in Fig. 9.

As illustrated in Figs. 8 and 12, the backup seal material A22 is a ring—shaped member having a substantially equal thickness dimension over the whole region and is formed of a non—polar substance. Moreover, the backup seal material A22 is disposed in a state contacted on the bottom surface of the cutout Alt. The adhesive A21 for joining these box culverts Al is poured into a space A23 n the inner surface of this backup seal material A22 and a plane connecting the inner surfaces of the box culverts Al . Here, a distance from the inner surface of the backup seal material A22 to the plane ting the inner surfaces of the box culverts A1, that is, a depth d2 of the space A28 in which the adhesive A21 is disposed is set to the width of this space A23, that is, 0.75 to 1.25 times of the distance w2 between the side surfaces of the opposing cutouts Alt.

AYWM memu.wmmmm i The adhesive A21 is disposed and has the configuration substantially similar to that according to the above—described first embodiment. That is, this ve A21 is poured into the inner side of the backup seal material A22 and has a function of joining the adjoining box ts A1 sandwiching this adhesive A21 as described above and also illustrated in Figs. 8 and 12. In other words, this adhesive A21 is disposed at a position faced with the al space of the box culvert A1.

Here, the stretch capacity of this adhesive A21 is 100 to 250% and the density is 0.8 to 1.0 g/cm3.

That is, in this embodiment, in joining the adjoiningloox culverts A1, such a procedure is taken that the cutout Alt is formed in each of the opposing joint surfaces Ala of the adjoining box culverts Al as illustrated in Fig. 10, the backup seal al A22 is contacted on the bottom surface of this .A1t as illustrated in Fig. 11, and further, the adhesive A21 is poured into the inner side of the backup seal material A22 as illustrated in Fig. 12, and waiting for solidification of the adhesive A21. When the adhesive A21 is to be poured in, the g processing similar to that according to the above~described first embodiment is performed. In this embodiment, too, in occurrence of unequal settling or ground displacement at an earthquake after a water l is formed, the layer in which this adhesive A21 is provided is deformed, and continuity and water tightness between the adjoining box culverts A1 are maintained.

As described above, by means of the joining method accordingix>thisembodiment, too,evenijioccurrence(Ifunequal ng or ground displacement at an uake, the adhesion n by the adhesive A21 follows it and deforms to ensure continuity and water tightness. That is, quake resistance, continuity, and water tightness can be given inexpensively and easily to the structure including a water channel such as a sewage, a passage and the like using a concrete product having a square cylindrical or U—shaped cross—section.

Moreover, with this joining method, too, since a primer is not , reduction of the number of man—hour and a construction period can be realized. [0041} Furthermore, according to this construction method, since all the works forming the joint portion A2 can be med inside the box culvert Al constituting the existing structure, no special work or processing is needed, and quake resistance, continuity, and water tightness can be given to the existing muuxwwwwrwx structure formed by using the box culvert A1 when necessary without shutting off the traffic for a long time. s [0042] uently,athirdembodimentofthepresentinvention 2 will be described by referring to Figs. 13 to 15.

Ajoiningnmthodofeaconcretestructureaccordingtotfids embodiment is applied to a fracture spot le where a fracture such as a crack or the like as illustrated in Fig. 13 occurs in a box culvert Bl constituting an existing underground structure such as a sewage formed by ting a plurality of the box culverts Bl, each being a square cylindrical concrete structure having a rectangular cross—section. This joining method will be described below with the ption of configuration of each part. Though the box culvert Bl, which is a square cylindrical concrete product, is described in this embodiment, it is needless to say that the present invention maybeappliedTXJathree—facewaterchannelformedofeaconcrete producthavingeaU—shapedcross—sectionformedofaapairtxfside plates and a bottom plate and having the upper side open.

Further, the present invention may be applied to a structure formed by casting concrete in place. 3 In this embodiment, at the fracture spot le, a cutout Blt having ainidth dimension w3 larger than this fracture spot le is provided on the inner surface side of the fracture portion as illustrated.in Fig. 14. Inside this cutout, a joint n B2 composed of disposing a backup seal material B22 formed of anon—polarsubstancewhichiseabackupnmterialandeniadhesive B21 is provided, respectively, from the outer surface side to the inner surface side of the box culvert B1 similarly to that according to the above—described second embodiment and as illustrated in Fig. 15. Here, the cutout Blt is formed by g away the existing box culvert B1 by using a concrete cutter or the like.

As bed above and also illustrated in Fig. 15, the joint portion B2 is formed inside the cutout formed in the re portion of the box culvert B1 and constituted by disposing the backup seal material 1322 and the adhesive B21 from the outer surface side to the inner e side of the box culvert Bl. Here, the cutout Blt is formeciby cutting away the existing box culvert B1 by using a concrete cutter or the like.

As illustrated in Fig. 15, the backup seal material 822 is a member having a substantially equal thickness dimension over the whole region and is formed of a non—polar substance.

Moreover, this backup seal material B22 is disposed in a state contactedcnithebottomsurface(flithecutoutBlt. esive 821 for joining the re spot le of the box culvert Bl is poured into a space B2s between the inner surface of this backup seal material 822 and the inner surface of the box t B1 as illustrated in Fig. 15. A depth of this space B2s, that is, the distance d3 from the inner surface of the backup seal material B22 to the inner surface of the box culvert B1 is set to 0.75 to 1.25 times of the width dimension w3 of the cutout Blt. [0047} The adhesive B21 is disposed and has a configuration ntially similar to that according1u>the above—described first embodiment. That is, this adhesive B21 is poured into the inner side of the backup seal material B22 as described above and illustrated in Fig. 15 and has a function of joining the fracture spot le of the box culvert Bl. In other words, this adhesive B21 is disposed at a position with the internal space Bls of the box culvert B1. Here, the stretch capacity of this adhesive B21 is 100 to 250% and the density is 0.8 to 1.0 g/cm3.

That is, in this embodiment, in joining the adjoiningloox culverts Bl, such a procedure is taken that the cutout Blt is formed as illustrated in Fig. 14 at a spot where fracture occurs in any of the top plate, the side walls, and the bottom plate of the box culvert Bl forming an existing pipeline by using a cuttingtoolsuchaseaconcretecutter,thebackupsealnmterial 822 is contacted on the bottom surface of this cutout Blt, and r, the adhesive 821 is poured into the inner side of this backup seal al 822 as rated in Fig. 15, and.waiting for solidification of the adhesive 821. When the adhesive 821 is to be poured in, the masking processing similar to that accordingtotheabove—describedfirstembodimentisperformed.

In this embodiment, too, in occurrence of unequal settling or ground displacement at an earthquake after a water channel is formed, the layer in which this adhesive 821 is provided is deformed, and continuity and water tightness n the adjoining box culverts Bl are maintained.

As described above, by means of the joining method according to this ment, even in occurrence of unequal settling or ground displacement at an earthquake, the on portion by the adhesive 821 follows it and deforms to ensure continuity and water tightness. That is, quake resistance, continuity, and water tightness can be given inexpensively and easily to the structure including a water channel such as a sewage, a passage and the like using a concrete product having a rectangular or U—shaped cross—section.

Moreover, with this joining method, too, since a primer is not needed, reduction of the number of man—hour and a construction period can be ed.

Furthermore, according to this construction , since all the works forming the joint portion B2 can be performed inside the box culvert Bl constituting the existing structure, no special work or processing is needed, the fracture spot le is repaired when necessary without shutting off the traffic for a long time, and quake resistance, continuity, and water tightness can be given to the ng structure formed by using the box culvert B1 or concrete cast in place.

The present invention is not limited to the described embodiments.

For example, the joining method of the present ion may be employed for a joint portion between a box culvert Cl and a manhole C3 as illustrated in Figs. 16 and 17. :2 This joint portion C2 in this mode is § constituted by disposing aloackup seal material C22 and an adhesive C21 in the order from the outer surface side of the manhole C3 in a space formed between the lower part of the box culvert Cl and the e C3. The backup seal material C22 in this mode is a rod—shaped member having a circular cross—section, and a pluralityofthemarearrangedadjacentlyinthecbpthdirection ofthisspace. er,iJlthisnmde,easheet—shapedcovering material C24 made of rubber, for example, is attached on the outer surface of the manhole C3 so as to cover the backup seal material C22. On the other hand, the adhesive C21 having stretch capacity of 100 to 250% and density of 0.8 to 1.0 g/cm3 similar to those in the first to third embodiments is used. A cutout C3a is provided between the adhesive C21 and an invert C31 provided on the lpart of the e C3, and a spacer C25 formed by a styrene foanlis inserted into this cutout C3a.

Furthermore, a mortar C26 is filled above this spacer C25 so that the upper face becomes flush with the upper face of the invert C31.

With the joining method in this mode, too, even in occurrence of unequal settling or ground displacement at an earthquake, the adhesion portion by the adhesive C21 s it and deforms to ensure continuity and water tightness. That www.mmmmum. is, quake resistance, continuity, and water tightness can be “400M given inexpensively and easily to the joint portion between the box culvert Cl and the manhole C3. rmore, in forming the joint portion in this mode, since all the works can be performed inside the manhole C3, quake resistance, continuity, and water tightness can be given when necessary without shutting off the c for a long time.

In addition, in construction of a structure newly formed by laying a plurality of te structures formed.in advance prior to laying of a box culvert and the like, it is needless to say that the g method as that in the first embodiment of the present invention may be employed for a joint portion between the adjoining te products.

The present ion may be also d to a structure formedkn/casting'concretejJIplace, not limitedixnthose formed by connecting a plurality of concrete structures formed in advance prior to laying. That is, in a structure constituted by a plurality of concrete structures formed by casting concrete in place and having a gap provided between the adjoining concrete structures, the concrete structures may be joined by the joining method as that according to the above-described WWW.» second embodiment, or a broken spot of a structure formed by casting concrete in place may be joined by the joining method as that according to the abovewdescribed third embodiment. x: Furthermore,ijlanexistingconcretestructureformedentirely i by casting concrete in place, the joining method of forming a i recess groove in the whole periphery of the inner surface, disposing a backup seal material on a bottom surface side of this recess groove, and pouring an adhesive on the side opposite to the bottom surface of the recess groove of the backup seal material. Moreover, the present invention may be applied to a structure having other sectional shapes such as a circle, a semi—circle and the like, not d to the rectangular sectional shape.

Other various deformations are possible within the range not departing from the gist of the present invention.

Reference Signs List 1, A1, B1, C1 box culvert ete t) 2, A2, 82, C2 joint portion 21, A21, B21, C21 adhesive 22, A22, B22, C22 backup seal material

Claims (7)

1. A joining method of a concrete structure, comprising steps of: laying a ity of concrete structures, each having a cylindrical or U—shaped cross—section, separately from each other only by a predetermined dimension; installing' a backup material made of a non—polar substance at a portion separated from the inner surface of the te structure; and pouringeniadhesivehavingstretchcapacityoflOO1x>250% and<density'of 0.8 to 1.0 g/CHP into a space between the e of the backup material and the inner surface of the concrete ure so as to form a joint portion.

2. The joining method of a concrete structure according to claim 1, wherein a depth of the space is 0.75 to 1.25 times of a separation width between the concrete structures.

3. The joining method of a concrete structure according to claim 1 or 2, wherein an outer backup al is arranged outside the backup material.

4. A joining method of a concrete structure, comprising steps of: unvauxvxxm)uw4kl formingaarecessgroovejjlthewholeperipherycflfaninner surface of the te structure, in an existing concrete ure having a cylindrical or U—shaped cross—section; installing a backup material ofeanon—polar substance in aportion:h1thisrecessgrooveseparatedfrmntheinnersurface of the concrete structure; and g an adhesive having h capacity of 100 to 250% and density of 0.8 to l.0 g/cnfi intC)a space between the surface of the backup material and the inner e of the concrete structure so as to form a joint portion.

5. The joining method of a concrete structure according to Claim 4, wherein the existing concrete structure is formed by laying a plurality of concrete products having a cylindrical or U—shaped cross—section.

6. The joining method of a concrete structure according to claim 5, wherein the recess groove is formed in the inner surface of the joint portion between the adjoining concrete products.

7. The joining method of a concrete structure according to claim 4 or 5, wherein the recess groove is formed at.a broken spot in the inner surface of the concrete structure.