JP6187738B2 - Sectional repair method for concrete structures - Google Patents

Description

  The present invention relates to a method for repairing a cross section of a concrete structure that has deteriorated or broken.

  Conventionally, in various concrete structures such as bridge structures, building structures, harbor structures, factory plants, road structures, etc., repair or neutralization when concrete cross-sections are lost or dropped due to deterioration or impact, etc. There is known a cross-section repair method that is a repair method for the purpose of cross-section repair when a portion including deterioration factors such as frost damage and salt damage is removed.

  In such a concrete structure, the cross-section restoration method for restoring / repairing the cross section of a deteriorated or damaged portion (hereinafter collectively referred to as a deteriorated portion) to the original cross-sectional shape is first of all a deterioration in the concrete structure. The part and the surrounding part are removed from the concrete frame as a section to be repaired. Specifically, for example, a concrete surface (concrete surface) exposed by a concrete cutter as disclosed in Patent Document 1 is cut linearly so as to surround the four sides of the section to be repaired. Use a special device such as a jet to hang (remove) the section to be repaired, and expose the sound part behind the concrete surface rather than the deteriorated part. Next, by filling the removed space with a cross-sectional restoration material such as mortar, the concrete structure can be restored and restored to the original cross-sectional shape.

JP 2010-247434 A

  By the way, a crack (crack) may occur in the portion where the cross-sectional repair has been performed (the cross-section repaired portion).

  As a factor that causes the crack, for example, stress is concentrated on the corner portion of the repaired portion of the cross section due to the cohesive force of the cross section repair material itself at the time of curing after filling the cross section repair material.

  As shown in FIG. 17 (which is a schematic diagram viewed from the a direction in FIG. 15 schematically showing the concrete bridge C1 as a construction site), the conventional cross-sectional repair method has a corner (corner) U32 as shown in FIG. Stress concentrates in the vicinity of the corner of the section repaired portion U2X formed by filling the section repair material into a space (space from which the section repair target portion is removed) that is substantially perpendicular. In particular, when mortar is used as a cross-section restoration material, the mortar's high adhesive strength achieves integrity with the surrounding concrete (concrete frame CF). It is conceivable that an internal tensile force is generated in the mortar itself due to the force, which causes a crack.

  Further, even when the cross-section repair work is being performed, external forces and the gravity of the structure itself act on the concrete structure, causing the deformation of the concrete frame CF such as deformation and vibration. Since the cross-section repair work such as the concrete bridge C1 and the bridge girder as shown in Fig. 16 is also carried out while the vehicle is passing, as shown in Fig. 16, the concrete frame CF moves such as bending deformation and vibration accompanying the passing of the vehicle. Frequently occur continuously. In FIG. 16, the state where the concrete bridge girder, which is the concrete frame CF, is bent and deformed by the passage of the vehicle is exaggerated.

  In cross-section repair work performed under such conditions, depending on the construction position, the work will be carried out with considerable deformation and vibration, and the material strength of the cross-section repair material is low at the initial stage of curing. Thus, cracks are likely to occur in the repaired section U2X due to bending deformation and vibration of the concrete frame CF. In particular, as shown in FIG. 17, cracks are likely to occur in the corner portion U32 of the cross-sectional repaired portion U2X. FIG. 17 schematically shows a direction in which a crack is generated from the corner portion U32 of the cross-sectional repaired portion U2X.

  In addition, since the moisture evaporation of the cross-sectional repair material U2 (mortar) is likely to occur from these cracks, the drying shrinkage proceeds, and a new crack is generated in the cross-section repaired portion U2X. As shown in FIG. 18, the adhesive force between the surrounding concrete (concrete frame CF) and the cross-section repair material U2 is reduced, and the cross-section repair material U2 and the concrete frame CF are easily peeled off. There is a concern that the cross-section repair material U2 may be peeled off or peeled off from the concrete housing CF due to the movement of the housing CF. In FIG. 18, the cross-sectional repair material U2 in a state of being peeled from the concrete housing CF is schematically shown by a broken line.

  In addition, when cross-section repair work is performed for bridges and bridge girders that have a large amount of vehicle traffic, even after the cross-section repair work is completed, deformation and vibration occur in the concrete frame CF due to external forces due to movement of the car, For example, a crack may occur in the corner portion U32 in the portion U2X whose cross section has been repaired within a few days after the construction. This is because tensile stress is generated from the corner of the repaired portion U2X as a starting point by the shearing force acting on the bridge girder (shearing force indicated by the arrow in FIG. 17), and this tensile stress level is the tensile force of the sectional repairing material U2. It is considered that cracks occur due to exceeding the strength.

  Furthermore, if a crack occurs in the repaired section U2X after the section repair work is completed, the moisture in the mortar evaporates from this section, and as the moisture evaporation in the mortar proceeds, the section contraction occurs. The adhesive force of the cross-sectional repair material U2 is reduced. As a result, even after completion of the cross-section repair work, the cross-section repair material U2 and the concrete housing CF are easily peeled off, and the cross-section repair material U2 may be peeled off from the concrete housing CF due to the movement of the concrete housing CF such as bending deformation and vibration. Can occur (see FIG. 18).

  Cracks caused by cross-section repair work include self-shrinkage, drying shrinkage, linear expansion coefficient, static elastic modulus, cross-section repair material characteristics such as adhesion to the substrate, and other factors such as weighting and construction quality. The crack resistance of the cross-section repair work needs to be comprehensively determined in consideration of these factors. However, at present, the mechanism of cracking has not been fully elucidated.

  In order to find a cross-sectional repair method capable of preventing and suppressing the occurrence of cracks based on such various factors, the present inventor has intensively studied and focused on the following points in the conventional cross-section repair method.

  First, the first part is a cut portion U3 made of a combination of a straight line portion U31 and a corner (corner) U32 in the concrete surface CS with a concrete cutter or the like so as to go around the four sides of the section to be repaired. The shape of the opening of the removed portion formed in this state is substantially rectangular when viewed from the concrete surface CS side, and the corner U32 of the section repaired portion U2X formed by filling such a removed portion with the section repair material U2 is provided. The starting point is a crack (see FIG. 17). In particular, when a cut U3 is made on the concrete surface CS in a straight line with a concrete cutter, the cut of the intersecting L-shaped cutters is formed on the outside of the corner in the removal space after the suspension is removed, as schematically shown in FIG. The trace U33 remains and is likely to cause a new crack.

  The second point is that when the cut U3 is made in the concrete surface CS with a normal concrete cutter, the cut U3 is made at an angle substantially perpendicular to the concrete surface CS, and the deteriorated portion of the concrete is cut along the cut angle θ. In order to remove, the cut surface that defines the removed space (the surface in the direction from the concrete surface CS toward the back) becomes a surface that is substantially perpendicular to the concrete surface CS, and is surrounded by such a cut surface (removal) The space is filled with the cross-sectional repair material U2 (see FIG. 18). That is, if such a removed portion is filled with the cross-section repair material U2, the adhesion surface (contact surface) between the concrete frame CF and the cross-section repair material U2 becomes a surface substantially perpendicular to the concrete surface CS. When a crack occurs in the repaired section U2X formed by filling the material U2, the moisture of the section repair material U2 evaporates from this section, and the amount of contraction of the section increases according to the amount of evaporation of the moisture. The adhesive force of the cross-sectional repair material U2 to the CF is reduced, and it becomes easy to peel from the concrete frame CF. If bending deformation or vibration occurs in the concrete housing CF under such a state, an interface peeling phenomenon occurs in which the cross-section repair material U2 is peeled off from the adhesive surface with the concrete housing CF, and there is a risk of falling off.

  Focusing on the above points, the inventor of the present application has come up with a method for repairing the cross section of a concrete structure that can prevent or suppress the occurrence of cracks and prevent or suppress the situation where the cross-section repair material peels off the concrete frame. It was.

  That is, according to the present invention, a concrete surface is formed into a shape in which a single substantially quadrangular shape or a plurality of substantially quadrangular shapes are connected to each other by using a cutting means on a concrete surface so as to surround a section to be repaired in a concrete structure. In a method for repairing a cross section of a concrete structure, in which a portion surrounded by the cut is removed and a new cross section is formed by filling the removed portion with a cross section repair material, a straight portion corresponding to the side of the cut Is cut with the cutting means so that the cutting angle with respect to the concrete surface along the cutting depth direction is such that the tip in the cutting depth direction is further away from the cross-section restoration target portion than the base end in the cutting depth direction. The taper-shaped cutting process that inclines at a predetermined angle with respect to the surface, and of the cutting The when cutting by the cutting means, corners is characterized by comprising a rounded shape cut process cuts so that partial arc shape.

  Here, “substantially square” in the present invention is a concept including not only “substantially rectangular” but also a rectangle other than a rectangle (for example, a parallelogram or a trapezoid). In addition, the “cut” in the present invention having such a substantially square shape as a basic shape includes both a single substantially square shape and a shape in which a plurality of substantially square shapes are connected to each other. The When the cut is in the former shape (single substantially quadrangular shape), the cut 3 has four sides (straight line portions) 31 and four corners (more specifically, sides as shown in FIG. 1). 4 corners) that can intersect at an angle of less than 180 degrees. On the other hand, when the incision is the latter shape (a shape in which a plurality of substantially squares are connected to each other), this incision 3 is, for example, as shown in a representative example in FIGS. It consists of at least six or more sides 31 and at least six or more corners 32. The corner 31 has an entry corner 32 (I) where the sides 31 can intersect at an angle of less than 180 degrees, and the sides 31 have 180. There is both an exit corner 32 (O) that can intersect at an angle greater than degrees. In addition, in FIG. 2, the part partitioned off by the substantially quadrilateral which makes a basic shape is shown with a mutually different pattern. Moreover, the line | wire of the edge | sides (opposite side) which opposes across a cross-section restoration object part among cuts. The length of the minutes may be the same or different. The “section repair target part” is a part that should be restored to a new section. Basically, the part of the concrete structure that is a combination of the deteriorated or damaged part (deteriorated part) and its peripheral part Although it means, it is also possible to regard the deteriorated part itself as a section repair target part. Further, the “cutting means” in the present invention is not particularly limited as long as it can cut the concrete surface, such as a concrete cutter or a drill, and a taper shape cutting process or a round shape cutting using a plurality of different types of cutting means. It is also possible to carry out the process.

  In the method for repairing a cross section of a concrete structure according to the present invention, it is asked whether a corner (an entry corner or an exit corner) of a space (removal space) from which a cross-section repair portion has been removed by passing through an R-shaped cutting process. All corners) have a partial arc shape (hereinafter referred to as a round shape) of approximately a quarter of a circle, and when the cross-sectional repair material filled in such a removal space is cured, the repaired cross-sectional portion (hereinafter referred to as “cross-section”). Concentration of the cohesive force of the cross-sectional repair material itself on the corner portion of the “repaired portion”) can be effectively avoided. Therefore, for example, when mortar that exhibits high adhesive strength is used as a cross-section repair material, and the integrity of the cross-section repaired part and the surrounding concrete (a healthy concrete frame) is achieved, the cohesive force associated with the hardening of the mortar Even if an internal tensile force is generated in the mortar itself due to the restraining force of the surrounding concrete, the internal tensile force acting on the corner of the repaired portion of the section is smaller than when the corner of the removal space is a right angle. It can be reduced, and the occurrence of cracks can be prevented / suppressed. Moreover, if it is the cross-sectional repair process of this invention which passes through a round shape cutting process, the crossed L-shaped cutting trace does not appear on the outer side of the corner (corner) of the removal space prescribed | regulated by cutting, but a cutting trace It is possible to prevent the occurrence of new cracks due to the above.

  And, if the cross-sectional repair method according to the present invention is capable of preventing and suppressing the occurrence of cracks that are likely to occur at the corners of the cross-section repaired portion, it prevents moisture evaporation of the cross-sectional repair material through the cracks. As a result, new cracks may occur in the repaired section due to drying shrinkage caused by moisture evaporation, and long-term adhesion between the repaired material and the concrete frame may be reduced due to the crack. It is possible to prevent / suppress the occurrence of peeling and peeling of the accompanying cross-sectional repair material. Therefore, according to the cross-section repair method of the present invention, even after the cross-section repair work is completed, the cross-section repair material and the concrete frame are separated, or the cross-section repair material becomes a concrete frame due to the movement of the concrete frame such as bending deformation and vibration. It can be expected to prevent / suppress the situation where it peels off.

  In addition, if the cross-section repair method of the present invention is applied when performing cross-section repair work on concrete structures such as bridges and bridge girders that have a large amount of vehicle traffic, external force due to passing of vehicles after the cross-section repair work is completed. Even if tensile stress is generated from the corner of the repaired section due to the shearing force acting on the concrete casing due to bending deformation or vibration, the corner of the repaired section is rounded. Therefore, this tensile stress can be effectively reduced, and the occurrence of cracks caused by the tensile stress exceeding the tensile strength of the cross-sectional repair material can be effectively prevented / suppressed.

  In particular, in the present invention, when the corner portion of the removal space is a right angle by making the corner portion of the space (removal space) from which the cross-section repair portion is removed, the corner portion is filled with the cross-section repair material. In addition, the air in the corner portion easily escapes from the removal space, so that so-called air accumulation is less likely to occur, the degree of adhesion of the cross-sectional repair material to the concrete frame in the corner portion is improved, and it can be generated by the presence of air accumulation after the filling process It is possible to prevent or suppress the peeling or deterioration of the repaired section.

  Furthermore, the method for repairing a cross section of a concrete structure according to the present invention is configured such that the cutting angle with respect to the concrete surface along the cutting depth direction by the cutting means is greater than the base end in the cutting depth direction at the distal end in the cutting depth direction. In order to go through a taper-shaped cutting process that inclines at a predetermined angle with respect to the concrete surface so as to be separated from the target part, the cross-section repair material is filled into the part removed along the cutting that is partitioned into a substantially rectangular shape by such a straight part. By doing so, the adhesion surface (contact surface) between the hardened cross-section restoration material and the concrete frame is not a plane perpendicular to the concrete surface, and the tip in the depth direction of cut is more cross-sectional than the base end in the depth direction of cut. The taper surface is inclined at a predetermined angle in a direction away from the portion to be repaired. As a result, interfacial debonding occurs when the cross-section repair material is peeled off from the contact surface with the concrete housing due to, for example, drying shrinkage of the cross-section repair material with respect to the concrete body, or a decrease in the adhesion of the cross-section repair material due to flexural deformation or vibration Even if the phenomenon occurs, it is possible to prevent the cross-sectional repair material from being peeled off from the concrete frame due to the shear resistance of the tapered surface.

  In addition, the cross-sectional repair method in this invention may perform a taper shape cutting process and a round shape cutting process simultaneously, and may be performed by a time difference.

  Further, in the method for repairing a cross section of a concrete structure of the present invention, in the taper-shaped cutting process, the cutting angle with respect to the concrete surface along the cutting depth direction by the cutting means can be set to an appropriate value. Through the test, the inventors have found that the above-described effects can be effectively obtained particularly when the cutting angle is 15 degrees or more and 45 degrees or less. In particular, it has been found that when the cutting angle in the taper-shaped cutting step is 25 degrees or more and 35 degrees or less, an even higher effect is obtained.

  Further, in the method for repairing a cross section of a concrete structure according to the present invention, across the surface exposed to the concrete surface side of the cross-section repair material filled in the removed portion, and the concrete surface around this surface, By passing through a reinforcing material application step of applying a reinforcing material having flexibility and toughness, the occurrence of cracks can be more effectively prevented and suppressed, and the adhesion of the cross-section repair material to the concrete frame can be reduced. Even when the interface peeling occurs due to the decrease, it is possible to prevent the cross-sectional repair material from peeling off due to the flexibility and toughness of the reinforcing material.

Furthermore, cross-sectional in the repair direction, Earl shape cut process, when the cutting by the cutting means the angular notch, the sectional repair than the base end in the depth direction cut the tip in the depth direction cut target portion of the present invention If the step of inclining at a predetermined angle with respect to the concrete surface is included so as to be separated from the surface, not only the straight portion of the cut but also the corner becomes a tapered shape inclined at the predetermined angle along the cut depth direction. By removing the part surrounded by the notch and filling the removed part with the cross-section repair material, the entire area of the adhesion surface (contact surface) between the hardened cross-section repair material and the concrete frame is Instead of a right-angled surface, the tip in the cut depth direction is inclined at an angle that is farther from the cross-section repair target part than the base end in the cut depth direction. Even if the interfacial debonding phenomenon occurs in which the cross-section repair material peels off the contact surface with the concrete frame, the shear resistance of the taper surface increases as the taper area increases. The situation of peeling off from the concrete frame can be prevented with a higher probability.

  According to the present invention, by passing through the round shape cutting process, the corner of the repaired section is rounded, whereby the force gathered at the corner can be dispersed (stress dispersion) to prevent / suppress the occurrence of cracks. At the same time, through the taper-shaped cutting process, the cross-section restoration material is made into a reverse taper shape from the concrete surface side toward the back in the depth direction, so that the cross-section restoration material becomes a concrete frame. It is possible to realize a structure that is held by the steel and does not peel off from the concrete frame.

The figure which shows an example of a single substantially square-shaped cut in this invention. The figure which shows the specific example of the notch | incision of the shape which connected the some substantially square shape mutually in this invention. The figure which shows typically an example of the field which constructed the cross-section repair work by the cross-section repair method of the concrete structure which concerns on one Embodiment of this invention. The figure which shows typically the state seen from the a direction of FIG. The principal part expansion schematic diagram of FIG. The figure which shows the state immediately after a cutting process in the cross-section repair method which concerns on the embodiment corresponding to FIG. The figure which shows the state immediately after a removal process in the cross-section repair method which concerns on the embodiment corresponding to FIG. The figure which shows the state immediately after a cross-section repair material filling process in the cross-section repair method which concerns on the embodiment corresponding to FIG. The figure which shows the state immediately after a reinforcing material application | coating process in the cross-section repair method which concerns on the embodiment corresponding to FIG. The figure which shows typically the concrete structure which bends and deforms in the construction site shown in FIG. The figure which shows typically the state of the punch test which calculates | requires the effective range of the taper angle which should be employ | adopted in the taper shape cutting process of the cross-section repair method which concerns on the embodiment. The figure which shows a part of test body used for the same punching test. The figure which shows the test result of the same punching test. The figure which shows the shape of the cut in the other modification of the embodiment corresponding to FIG. The figure which shows typically an example of the field which implemented the cross-section repair construction by the cross-section repair method of the conventional concrete structure corresponding to FIG. The figure which shows typically the state which the concrete structure is bending and deforming in the field shown in FIG. The figure which shows typically the state seen from the a direction of FIG. The schematic diagram which shows the principal part of FIG. 15 corresponding to FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The method of repairing a cross section of a concrete structure according to the present embodiment is a method of deteriorating or damaging a concrete frame in a concrete structure (hereinafter collectively referred to as “degraded part”) and the sound surrounding it. This is a method applicable when a concrete structure is restored to its original cross-sectional shape by removing the portion as a cross-section restoration target portion and filling the removed space (removal space) with a cross-section restoration material.

  In the following, for example, a deteriorated portion appearing on a downward surface CS of a bridge C1 (concrete structure) arranged at a position straddling a plurality of piers C2 as shown in FIG. A section repairing method applied when removing a healthy concrete portion in the section as a section repair target section and forming a new section (section repaired section 1) in the removed space will be described.

  The method for repairing a cross section of a concrete structure according to the present embodiment includes a cutting process of cutting the concrete surface CS into a substantially square shape by a cutting means so as to surround the four sides of the cross section repair target portion 1 in the concrete structure C1, and a cutting process. This is a method of passing through a removal step of removing a portion cut into a square shape and a cross-sectional repair material filling step of filling the cross-section repair material 2 into the removed portion (removal space S). And the cross-section repair method of this invention has the characteristics in the point which passes through a taper shape cutting process and a round shape cutting process in a cutting process.

  As shown in FIGS. 4 and 5 (FIG. 4 is a diagram schematically showing the state seen from the direction a in FIG. 3, and FIG. 5 is an enlarged schematic view of the main part of FIG. 3). In addition, an angle obtained by inclining a straight portion 31 corresponding to at least a side of the substantially rectangular cut 3 with a predetermined angle instead of a right angle with respect to the concrete surface CS (the downward surface CS of the bridge C1 in this embodiment). This is a processing step of cutting into a tapered shape. In the present embodiment, for example, about 10 mm is cut from the concrete surface CS toward the back by an appropriate cutting means. At this time, at least the straight portion 31 is along the cutting depth direction A as shown in FIG. In other words, the cutting angle θ of the virtual straight line along the cutting depth direction A with respect to the concrete surface CS is less than 90 degrees so that the relative angle (inner angle) θ between the virtual straight line and the concrete surface CS is less than 90 degrees. Cut so that More specifically, the taper-shaped cutting step includes a tip in the cutting depth direction A in the relationship between the straight portions 31 (opposite sides 31) opposed to each other across the cross-section repair target portion 1 in the substantially rectangular cut 3. This is a process of cutting the concrete surface CS so as to surround the four sides of the section to be repaired 1 at a cutting angle θ at which the distance between 311 is larger than the distance between the base ends 312 in the cut depth direction A. That is, in the taper-shaped cutting step, the cutting angle with respect to the concrete surface CS along the cutting depth direction A is set such that the tip of the straight portion 31 in the cutting depth direction A is more than the base end of the straight portion 31 in the cutting depth direction A. The step of inclining by a predetermined angle with respect to the concrete surface CS so as to be separated from the cross-section repair target portion 1 (in other words, to position the tip of the straight portion in the cutting depth direction A at a position deviated from the cross-section repair target portion 1). It is.

Further, as shown in FIG. 4 and FIG. 6 (FIG. 6 is a diagram showing the state immediately after the cutting process corresponding to FIG. 4), the rounded cutting process includes the corner 32 of the substantially rectangular cutting 3. This is a processing step of cutting into a rounded partial arc shape. In the present embodiment, the corner 32 is set to be cut by an appropriate cutting means so as to have a rounded shape with a radius of about 20 mm, for example. Here, if the round shape cutting process is performed using an existing handy-type tool, it is easier to construct and work efficiency than when a large tool is fixed to the construction site and the round shape cutting process is performed. The round shape of the corner 32 that can be constructed with a handy type tool has a radius of about 20 mm. Of course, as long as construction can be performed appropriately, the radius of the round shape of the corner 32 is not limited to about 20 mm, and may be set to an appropriate value. Here, when the notch 3 has a substantially quadrangular shape, all the corners 32 are corners where the sides 31 can intersect at less than 180 degrees (approximately 90 degrees in the illustrated example), and the cross-sectional repair according to the present embodiment In the direction, such a corner 32 is rounded.

Furthermore, in the round shape cutting process in the present embodiment, the concrete surface CS (in the present embodiment, the downward surface of the bridge C1 in the case of cutting not only the straight portion 31 but also the corner 32 of the substantially rectangular cut 3). It is set so as to cut in a tapered shape at an angle inclined by a predetermined angle, not at a right angle to (CS). That is, when the corner 32 of the cut 3 is cut by the cutting means, the tip of the corner 32 in the cut depth direction A is farther from the cross-section repair target portion 1 than the base end of the corner 32 in the cut depth direction A (in other words, For example, the tip of the corner 32 in the cutting depth direction A is positioned at a position deviated from the cross-section repair target portion 1), and is inclined at a predetermined angle with respect to the concrete surface CS.

  Such a taper-shaped cutting process and a rounded-shaped cutting process may be performed simultaneously, or may be performed with a time difference. In the case of performing the time difference, it is possible to appropriately select which of the taper-shaped cutting process or the round-shaped cutting process is performed first, and the linear portions 31 and the corners 32 of the substantially rectangular-shaped cutting 3 are alternately alternated. When forming the film, the taper-shaped cutting process and the round-shaped cutting process may be performed alternately. From the viewpoint of improving the efficiency of the cross-section repair work, first, a circular hole is drilled using a handy type drill (cutting means) at the corner of the cross-section repair target portion 1, and at that time, the concrete surface CS is turned into the concrete frame. The direction in which the hole is drilled toward the back of the CF is set in a direction inclined at a predetermined angle with respect to the concrete surface CS so that the tip of the drill is positioned at a position away from the cross-section repair target portion 1. Next, if a taper-shaped cutting process is performed by using a concrete cutter (cutting means) so as to connect adjacent holes, a substantially rectangular cut 3 having a substantially arc-shaped corner is formed on the concrete surface. It can form in CS, and a taper shape cutting process and a round shape cutting process can be performed smoothly and appropriately.

  The removal process is performed next to the cutting process including the taper-shaped cutting process and the round-shaped cutting process.

  As shown in FIG. 7, the removal step is a processing step of removing the cross-section repair target portion 1 cut into a substantially square shape by the cutting step, and the deteriorated portion is removed using a tool such as an electric pick or a water jet. This is a step of removing the portion 1 to be repaired from the concrete surface CS to a position of a predetermined depth and exposing a healthy concrete portion of the concrete frame CF. In addition, when removing the portion further deeper than the tip 311 of the cut 3 (tip 311 in the cut depth direction A), it may be removed at the same angle as the cut angle θ (taper angle θ). Of course, the suspension may be removed at an angle different from the cutting angle θ. Further, the surface exposed to the depth of the cut depth direction A from the tip 311 of the cut depth direction A of the cut 3 in the concrete frame CF may be a smooth surface as shown in FIG. It may be a rough surface.

  As shown in FIG. 8, the cross-sectional repair material filling step is a processing step of filling the cross-section repair material 2 into a portion (removal space S) removed in the removal step. In this embodiment, mortar is used as the cross-section repair material 2. Applicable. Moreover, in this embodiment, between the removal process and the cross-section repair material filling process, the primer treatment for applying a primer (water absorption adjusting material) to the surface exposed after the removal process in the concrete frame CF, and the removed space S When the reinforcing bar R appears, the anti-rust treatment is performed on the reinforcing bar R (not shown). The water absorption adjusting material may be any material that contributes to improving the adhesion at the contact surface between the cross-section restoration material 2 and the concrete frame CF filled in the removed space.

  In the present embodiment, following the cross-sectional repair material filling step, as shown in FIG. 9, the portion of the removal space S filled with the cross-section repair material 2 (cross-section repaired portion 2X) is substantially flush with the concrete surface CS. The reinforcing material 4 having flexibility and toughness over the exposed surface (cross-sectional repair material exposed surface 2XS) and the surface continuous with the cross-sectional repair material exposed surface 2XS of the concrete surface CS (for example, possible) A polymer coating mortar having flexibility and high toughness) is applied. In addition, in FIG.3, FIG4 and FIG.6, the reinforcing material 4 is abbreviate | omitted for convenience of explanation.

  By passing through the above processes, the cross-section restoration target portion 1 including the deteriorated portion of the concrete frame CF is removed, and the cross-section restoration material 2 filled in the removed portion is integrated with the surrounding concrete frame CF by a high adhesive force. A continuous cross section can be formed (see FIG. 9).

  By the way, an internal tensile force is generated in the cross-sectional repair material 2 due to the cohesive force accompanying hardening and the binding force of the surrounding concrete frame CF. If this internal tensile force is excessively concentrated on the corner portion filled in the periphery of the entering corner 32 of the removal space S in the repaired portion 2X of the cross section, cracks may occur. In the conventional cross-section repair method, as shown in FIG. 17, in the cutting process before removing the cross-section repair target part including the deteriorated part, the straight line part in which the corner U32 of the rectangular cut U3 corresponds to the side of the square. The corners (entrance corners) of the space from which the repair target portion is removed along the cuts U3 are naturally sharp corners. When such a removal space is filled with the cross-sectional repair material U2, stress is concentrated at the corner of the cross-section repaired portion U2X, and cracks are likely to occur. In particular, as shown in FIG. 16, an excessive shearing force acts on the concrete frame CF where the deformation and vibration can continuously occur in the concrete frame CF, such as where the amount of vehicle traffic is large, and the cross-section repaired portion U2X Tensile stress is generated starting from the corner. Cracks occur when the tensile stress generated at this time exceeds the tensile strength of the cross-sectional repair material U2.

  However, in the cross-sectional repair method according to the present embodiment, the corners 32 of the substantially rectangular cut 3 are rounded into a rounded round shape as shown in FIGS. Therefore, the internal tensile force (tensile stress) concentrated at each corner of the repaired portion 2X of the cross-section repair material 2 formed by filling the cross-section repair material 2 into the removal space S in which such rounded corners (corners) appear. The tensile stress acting around the round-shaped corner of the repaired portion 2X of the cross section is reduced, and the generation of cracks can be effectively prevented / suppressed.

  Accordingly, as shown in FIG. 10, the concrete body CF is deformed and vibrated due to the amount of traffic of the vehicle passing through the bridge C1 which is a concrete structure, and this is caused by the irregular movement of the concrete body CF. In the first place, even if the crack spreads out, the corner 32 of the notch 3 that defines the removal space S to be filled with the cross-section repair material 2 is rounded so that cracks do not occur or are extremely unlikely to occur. Can deal with. FIG. 10 exaggerates the state where the concrete bridge girder, which is the concrete frame CF, is bent and deformed by the passage of the vehicle.

  In addition, when the crack progresses, the moisture evaporation of the cross-sectional repair material 2 filled in the removal space S increases, and the crack further spreads due to drying shrinkage (cross-section shrinkage) of the cross-section repair material 2 itself, and concrete in the long term Although the adhesive force between the housing CF and the cross-section repair material 2 may be reduced and the cross-section repair material 2 may be peeled off, this embodiment can also prevent and suppress the occurrence of cracks at the initial stage of curing. It is possible to prevent and suppress by adopting the cross-sectional repair method according to the above.

  Furthermore, when the corner portion 32 is filled with the cross-sectional repair material 2 by passing through the rounded shape cutting step, the air in the corner portion 32 is easily discharged out of the removal space as a so-called air. It is difficult to cause accumulation, and the adhesion of the cross-section repair material 2 to the concrete frame CF at the corner portion 32 is enhanced, thereby preventing the cross-section repair material 2 from being peeled off or deteriorated due to the presence of an air reservoir after the filling process. Can be suppressed. In addition, when manually filling the cross-section repair material 2 into a square corner using a tool such as a trowel, the pressure (so-called soot pressure) when filling the cross-section repair material 2 into this corner is changed. There is a problem that it cannot be properly filled unless the pressure is much larger than the pressure at the time of filling the portion of the cross-sectional repair material 2. It is possible to properly fill even if the pressure is smaller than that when filling the cross-section repair material 2 into an angular corner, which is advantageous in terms of ease of filling (easy to apply). Contributes to improving work efficiency.

In addition, according to the sectional repair method according to the present embodiment, by going through the rounded shape cut step, the exposed surface of the concrete skeleton CF appearing upon removal of the cross repaired portion 1 including the degraded portion of the concrete skeleton CF (The contact surface with the cross-section repair material 2) is not 90 degrees with respect to the concrete surface CS, and the tip of the cut 3 in the cut depth direction A is more subject to cross-section repair than the base end of the cut 3 in the cut depth direction A A tapered surface inclined by a predetermined angle in a direction away from the portion 1 is formed. By filling the space surrounded by the tapered surface with the cross-sectional repair material 2, the cross-section repair material 2 after filling and hardening is held in the concrete frame CF. Thus, a structure that does not peel off from the concrete frame CF can be realized.

  Thus, the cross-section restoration material 2 is filled into the removal space S partitioned by the cut 3 whose opening area increases as the cut depth increases, and the contact surface (adhesion surface) between the cross-section restoration material 2 and the concrete frame CF is cut into the depth. By adopting the cross-section repair method according to this embodiment that can be formed into a wedge shape (tapered shape) inclined at a predetermined angle in the length direction A, external force acting on the drying shrinkage of the cross-section repair material 2 and the concrete frame CF after completion of the cross-section repair work Even when interface peeling occurs on the bonding surface between the cross-section repair material 2 and the concrete housing CF due to the cross-section, the cross-section repair material 2 is peeled off from the concrete housing CF due to the shear resistance due to the wedge shape of the concrete housing CF. It is possible to prevent the situation.

  Furthermore, in the cross-sectional repair method according to the present embodiment, after filling the cross-sectional repair material 2 (preferably immediately after filling), the exposed surface of the cross-section repaired portion 2X and the concrete frame CF continuous to this surface are exposed. Since the reinforcing material 4 (for example, polymer cement mortar) having flexibility and toughness is applied over the surface (concrete surface CS), a good bonding state between the reinforcing material 4 and the cross-sectional repair material 2 is ensured. Even if the cross-sectional repair material 2 is peeled off from the concrete frame CF, the cross-section repair material 2 can be held by the toughness and flexibility (fiber connection) of the reinforcing material 4.

  That is, the toughness of the reinforcing material 4 (polymer cement mortar) integrated with the cross-sectional repair material 2 even when the cross-sectional repair material 2 and the reinforcing material 4 are integrated and a crack occurs in the repaired portion 2X for some reason. The shape of the cross-sectional repair material 2 can be maintained by the bondability of the fibers and the cross-section repair material 2 can be prevented from peeling off. Therefore, it is possible to maintain a continuous appearance shape with the surrounding concrete frame CF even if it is a cross-sectional repaired portion where a crack has occurred.

  Furthermore, in the present embodiment, by making it possible to perform the reinforcing material application step immediately after the cross-sectional repair material filling step, the cross-sectional repair material 2 and the reinforcing material 4 can be firmly coupled to each other and integrated, Conventionally, concrete peeling prevention work that must be performed in a separate process from the cross-section repair work can be processed as one process of the cross-section repair method, which is also advantageous in this respect.

  Thus, by adopting the method for repairing a cross section of a concrete structure according to the present embodiment, the occurrence of early cracks after construction can be prevented / suppressed, and the concrete frame CF and the cross section repair material 2 can be attached. Even if the cross-sectional repair material 2 is peeled off from the concrete housing CF with the adhesion surface (contact surface) as a boundary as the adhesion force decreases, it can be structurally retained in the concrete housing CF.

  Further, by applying a reinforcing material 4 such as a polymer cement mortar having flexibility and toughness over the exposed surface 2XS of the section repaired portion 2X and its peripheral CS, the section repaired portion 2X and the section repaired portion The concrete frame CF surrounding 2X can be protected, and even if the section repaired portion 2X is deteriorated or the section repair material 2 is peeled off due to the corrosion expansion of the reinforcing bar R, the reinforcing material 4 becomes the cross section repaired portion 2X. Demonstrates the ability to prevent falling.

  The inventor conducted the following test in order to verify a more effective angle as the cutting angle (taper angle θ) with respect to the concrete surface CS in the taper-shaped cutting step in the cross-sectional repair method of the present embodiment.

In the test method, a steel material T1 whose outer peripheral surface is tapered is set at the center of a mold having a length of 300 mm, a width of 300 mm, and a thickness of 20 mm. A mortar plate T2 and a steel material T1 in a state where the compressive strength of the mortar (hereinafter referred to as “mortar plate T2”) has reached 40 N / mm ² is taken as a test piece T. The punch test was conducted. At that time, as shown in FIG. 11, the first pressure plate T3 is placed on the upper surface of the steel material T1, the first pressure plate T3 is pressed from above by the second pressure plate T4, and the upper surface of the first pressure plate T3. It measured with the load cell T5 arrange | positioned. Here, in the test body T, the steel material T1 corresponds to the section repaired portion 2X, the mortar plate T2 corresponds to the concrete frame CF, and the downward surface T21 of the mortar plate T2 corresponds to the concrete surface CS. In addition, the test body T is mounted on the receiving stand T7 arrange | positioned in the upward surface of the mount frame T6 of an Amsler type mortar compression tester.

  And the angle of the taper surface of the steel material T1 (more specifically, as shown in FIG. 12, it is an acute angle of the taper angle θ of the steel material T1 with respect to the horizontal downward surface T21 of the mortar plate T2, The test was conducted on four types of test bodies T, which were set to 15 degrees, 25 degrees, 35 degrees, and 45 degrees, respectively. Here, the reason that the test was not performed on the specimen T having a taper angle θ of less than 15 degrees is that if the taper angle θ is less than 15 degrees, an effective shear resistance cannot be obtained, and the wedge action is hardly exhibited. This is because the anti-peeling effect cannot be expected. Further, the test was not performed for the specimen T having a taper angle θ exceeding 45 degrees. When the taper angle θ exceeds 45 degrees, the vertical force acting on the mortar plate T2 corresponding to the concrete frame CF is excessive. This is because it is considered to act as a factor that destroys the mortar plate T2.

  Moreover, considering the crack of the mortar plate T2 itself due to the punching of the steel material T1, for each test body T, the steel material T1 is attached to the outer periphery of the mortar plate T2 to constrain the test body T, and “not restrained”. Each of the tests was performed in two modes of “no constraint”.

  The test results are as shown in FIG. From the test results shown in FIG. 13, it was found that the test body T having a taper angle θ of 45 degrees has the highest punching strength regardless of the restraint. However, since the taper angle θ is large, a bending deformation due to a punching load occurred in the mortar plate T2 in the unconstrained specimen T. Therefore, when any one load is applied to the concrete frame CF during the actual cross-section repair work or after the cross-section repair work is completed, the shear resistance obtained at the taper angle θ of 45 degrees is around the cross-section repaired portion 2X. This may act as a factor that partially destroys the healthy concrete (concrete frame CF), and may newly increase the risk of the cross-section repair material 2 being peeled off from the concrete frame CF. Therefore, setting the taper angle θ to 45 degrees is not an optimum angle although an effective wedge effect due to high shear resistance can be obtained.

  It was also found that the test specimen T having a taper angle θ of 15 degrees has an effective punching strength regardless of whether there is any constraint. However, it is considered that the specimen T having a taper angle θ of 15 degrees is not unlikely to drop out of the mortar plate T2 due to the small taper angle θ, as compared with the specimen T having a taper angle θ of 25 degrees. It is done.

  The test specimen T having a taper angle θ of 25 degrees has a punching strength of a test specimen T having a taper angle θ of 15 degrees and a test specimen having a taper angle θ of 35 degrees in any embodiment with or without constraint. It was found to be higher than T. Therefore, by setting the taper angle θ to around 25 degrees (about 25 degrees ± 5 degrees), it is possible to obtain a high punching strength without incurring bending deformation of the mortar plate T2, and to prevent peeling. I can expect.

  Further, the punching strength of the test specimen T having a taper angle θ of 35 degrees is lower than that of the test specimen T in which the taper angle θ is set to 25 degrees. The effect of preventing peeling can be expected.

  From the above considerations, the taper angle θ at which an effective wedge effect can be obtained is 15 degrees or more and 45 degrees or less, and the taper angle θ at which a particularly excellent wedge effect can be obtained is around 25 degrees to around 35 degrees (test results) Strictly speaking, it was found to be 25 degrees or more and 35 degrees or less.

  In addition, this invention is not limited to embodiment mentioned above. For example, the shape of the cut by the cutting means may be a shape in which a plurality of substantially squares are connected to each other as shown in FIGS. The reason for adopting the cut of such a shape is that, in the common concrete surface CS, when the deteriorated portions occurring at positions separated from each other are surrounded by individual substantially rectangular cuts, they are surrounded by the cuts. The removal spaces formed by removing the parts are also mutually independent spaces, and the parts surrounded by the adjacent cuts are connected to each other, rather than the method of filling each individual removal space with a cross-sectional repair material. This is because the method of filling the common space from which these connected portions are removed with the cross-section restoration material can improve the work efficiency and the smoothness of the concrete surface after the completion of the cross-section restoration work.

  The notch 3 having a shape in which a plurality of substantially quadrangular shapes are connected to each other includes a straight part 31 corresponding to the side and a straight part 31 viewed from a part surrounded by the notch 3 (cross-section repair target part 1). An angle that is an entry corner that can intersect at less than 180 degrees (hereinafter referred to as “entrance angle 32 (I)”) and an angle that is an exit corner at which the straight line portions 31 can intersect at an angle exceeding 180 degrees (hereinafter referred to as “outward angle”). Corner angle 32 (O) ").

  Then, when cutting the straight portion 31 and all the corners (incoming corner angle 32 (I) and outgoing corner angle 32 (O)) using the cutting means, the cutting angle with respect to the concrete surface CS along the cutting depth direction A The tip of the cut 3 in the cut depth direction A is farther from the cross-section repair target portion 1 than the base end of the cut 3 in the cut depth direction A (the tip of the cut 3 in the cut depth direction A is the cross-section repair target portion) The taper-shaped cutting process of inclining a predetermined angle with respect to the concrete surface CS so as to deviate from 1 and all the corners (incoming corner angle 32 (I) and outgoing corner angle 32 ( O)) is exposed to the concrete surface CS side of the round shape cutting process that cuts into a partial arc shape and the cross-section repair material 2 filled in the removed portion. If the reinforcing material applying step of applying the reinforcing material 4 having flexibility and toughness is applied to the surface and the concrete surface CS around the surface, the operational effects described in the above-described embodiments are obtained. Similar effects can be obtained. The shape of the notch 3 shown in FIG. 14 is an example of “a shape in which a plurality of substantially squares are connected to each other”, and a pattern in which a plurality of substantially squares are connected to each other and a shape of the notch defined by the pattern. Needless to say, is not limited to the shape shown in FIG.

  Further, in the taper-shaped cutting process according to the present invention, the cutting angle with respect to the concrete surface along the cutting depth direction when the cutting of the straight portion of the cutting is formed, the tip of the cutting in the cutting depth direction is the cutting depth direction. The step of inclining a predetermined angle with respect to the concrete surface so as to be farther from the cross-section restoration target portion than the base end of the incision is sufficient. You may set the cut angle with respect to the concrete surface along to about 90 degree | times like the past.

  It is also possible to apply a material other than mortar as the cross-sectional restoration material, or a material other than polymer cement mortar as the reinforcing material. Other examples of the cross-sectional repair material include graft materials such as concrete and non-shrink mortar, and organic or inorganic peeling prevention materials that are generally used as repair materials.

  In addition, the method for repairing a cross section according to the present invention can naturally be applied when repairing a concrete structure other than a bridge. Moreover, the concrete surface cut by the cutting means may be a side surface (standing surface) or an upward surface instead of the downward surface of the concrete structure.

  In addition, the specific processing of each process is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Section restoration object part 2 ... Section restoration material 3 ... Cut 31 ... Straight line part 32, 32 (I), 32 (O) ... Corner (corner)
4 ... Reinforcement material C1 ... Concrete structure (concrete bridge girder)
CS ... Concrete surface

Claims (5)

A concrete surface is cut into a shape of a single square or a plurality of squares connected to each other by a cutting means so as to surround a section to be repaired in a concrete structure, and surrounded by the cut. A cross-sectional repair method for forming a new cross-section by removing a portion that has been removed and filling a cross-section repair material into the removed portion,
When cutting the straight portion corresponding to at least the side of the cut with the cutting means, the cutting angle with respect to the concrete surface along the cutting depth direction is set so that the tip in the cutting depth direction is the base end in the cutting depth direction. A taper-shaped cutting step of inclining at a predetermined angle with respect to the concrete surface so as to be further away from the cross-section repair target part,
A method of repairing a cross section of a concrete structure, comprising: a round shape cutting step of cutting a corner of the cut so that the corner has a partial arc shape when the corner is cut by the cutting means. The method for repairing a cross section of a concrete structure according to claim 1, wherein the cutting angle in the taper shape cutting step is 15 degrees or more and 45 degrees or less. The method for repairing a cross section of a concrete structure according to claim 1, wherein the cutting angle in the taper shape cutting step is 25 degrees or more and 35 degrees or less. A reinforcing material having flexibility and toughness is applied over the surface exposed to the concrete surface side of the cross-sectional repair material filled in the removed portion and the concrete surface around the surface. The method for repairing a cross section of a concrete structure according to any one of claims 1 to 3, which undergoes a reinforcing material application step. When the round shape cutting step cuts the corner of the cut with the cutting means, the distal end in the cut depth direction is more distant from the cross-section repair target portion than the proximal end in the cut depth direction. The method for repairing a cross section of a concrete structure according to any one of claims 1 to 4, further comprising a step of inclining a predetermined angle with respect to the concrete surface.

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