JP2011149244A - Construction method for thickening upper surface of floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for thickening the upper surface of a floor slab for reinforcing a concrete floor slab of a road bridge by thickening its upper surface, wherein the necessary strength as the concrete floor slab is secured, the minimum construction thickness of a thickening layer is reduced, and a concern of corrosion is eliminated even in an area where antifreezing-agent is sprayed. <P>SOLUTION: An asphalt pavement 16 formed on the upper surface 14a of a concrete floor slab 14 is removed, to roughen the upper surface. The roughened upper surface 14a of the concrete floor slab 14 is then provided with a thickening layer 20 formed thereon with highly elastic resin mortar having a Young's modulus that is 1/3 or more of the Young's modulus of the concrete composing the concrete floor slab 14. Thereby, even if the minimum construction thickness of the thickening layer 20 is set to be relatively thin, the required strength is secured, which reduces a bending stress. The highly elastic resin mortar has salt-proofing properties, which eliminate the concern of the corrosion of reinforcing bars, etc., inside the concrete floor slab even in the area where the antifreezing agent is sprayed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a floor slab upper surface thickening method for thickening the upper surface of a concrete floor slab in order to reinforce the concrete floor slab of a road bridge.

  The concrete slabs of road bridges are subject to fatigue deterioration due to heavy traffic, traffic of overloaded vehicles, etc., and this causes a decrease in yield strength.

  As one of the methods for reinforcing the concrete floor slab with reduced proof stress and extending the life, a floor slab upper surface thickening method for increasing the upper surface of the concrete slab is conventionally known. .

  As the method of increasing the thickness of the upper surface of the slab, the asphalt pavement formed on the upper surface of the concrete slab is removed, and the upper surface of the concrete slab is roughened. A method of placing reinforced concrete as a thickened layer and then forming asphalt pavement on the upper surface of the steel fiber reinforced concrete has been widely used.

  In that case, in “Patent Document 1”, instead of placing the steel fiber reinforced concrete on the upper surface of the roughened concrete slab, the concrete is fixed in a state in which a strip-shaped steel plate that also serves as a reinforcing bar is fixed on the upper surface. Describes a method for increasing the thickness of a floor slab by forming a thickened layer by casting.

  Further, in “Patent Document 2”, instead of placing the steel fiber reinforced concrete on the upper surface of the roughened concrete floor slab, a resin mortar layer is interposed on the upper surface, and a fiber reinforcing layer is interposed as an intermediate layer thereof. A floor slab upper surface thickening method for forming a thickened layer by forming in a state is described.

JP-A-9-59929 JP 2004-169346 A

  As in the past, in the floor slab top surface thickening method in which steel fiber reinforced concrete is placed on the top surface of the concrete slab, the minimum construction thickness of the thickened layer is about 50 mm, so the concrete slab's own weight increases significantly. There is a problem that. Further, when this floor slab upper surface thickening method is applied in a region where the antifreezing agent is applied, there is a problem that corrosion of steel fibers is a concern.

  In this respect, even when the floor slab upper surface thickening method described in "Patent Document 1" is employed, the same problem occurs.

  On the other hand, when the floor slab upper surface thickening method is used in which the resin mortar layer is formed as a thickened layer on the upper surface of the concrete slab, the Young's modulus of the resin mortar is 1/10 of the Young's modulus of ordinary concrete. Since it is a value of the order and is considerably small, there is a problem that the function of the structural member for reinforcement cannot be given to the portion of the thickening layer.

  On the other hand, if the floor slab upper surface thickening method described in the above-mentioned “Patent Document 2” is employed, the strength can be increased to the extent that the fiber reinforcing layer is interposed as an intermediate layer. However, on the other hand, there is a problem that the minimum construction thickness is increased as much as the fiber reinforcement layer is interposed as an intermediate layer, and the construction cost is increased.

  The present invention has been made in view of such circumstances, and can secure the necessary strength as a concrete slab, and can reduce the minimum construction thickness of the thickening layer, and also an antifreeze agent. The object of the present invention is to provide a method for increasing the thickness of the upper surface of a slab that can eliminate the concern of corrosion even in a spraying area.

  The present invention is intended to achieve the above object by devising the structure of the thickening layer formed on the upper surface of the roughened concrete slab.

That is, the floor slab upper surface thickening method according to the present invention is:
In the floor slab upper surface thickening method to increase the upper surface of the concrete floor slab in order to reinforce the concrete floor slab of the road bridge,
After roughening the upper surface of the concrete floor slab, the upper surface of the roughened concrete floor slab is a Young whose value is 1/3 or more of the Young's modulus of the concrete constituting the concrete floor slab. The thickening layer is formed of a highly elastic resin mortar having a coefficient.

  The range of the “upper surface of the concrete floor slab” to which the upper surface thickening work is applied by the floor slab upper surface thickening method according to the present invention is not particularly limited, and may be the entire region or one of them. It may be a partial area.

  The above “highly elastic resin mortar” is a resin mortar whose Young's modulus is set to a value of 1/3 or more of the Young's modulus of the concrete constituting the concrete floor slab. The specific composition is not particularly limited.

  As shown in the above configuration, in the floor slab upper surface thickening method according to the present invention, on the upper surface of the roughened concrete slab, the ratio of the Young's modulus of the concrete constituting the concrete slab is 1 / Since the thickening layer is formed with a highly elastic resin mortar with a Young's modulus of 3 or more, the required strength is ensured even when the minimum construction thickness of the thickening layer is set relatively thin. can do. And thereby, in the concrete floor slab in which the thickening layer was formed, the bending stress degree can be reduced. Moreover, since the thickened layer formed of this highly elastic resin mortar is excellent in salt barrier properties, it is possible to eliminate the concern about corrosion of reinforcing bars and the like inside the concrete slab even in the area where the antifreezing agent is applied.

  As described above, according to the present invention, the minimum construction thickness of the thickening layer can be reduced while ensuring the necessary strength as a concrete slab, and the concern of corrosion can be eliminated even in the region where the antifreezing agent is applied. Can do.

  In addition, since the highly elastic resin mortar has excellent adhesion properties with concrete, it is possible to ensure the surface integrity of the thickened layer and the concrete slab without the need for an anchor or the like. And thereby, the construction cost for forming the thickened layer can be kept low. Moreover, it is possible to prevent the local concentration of the interfacial shear force from occurring in the concrete slab in which the thickened layer is formed. Further, it is possible to eliminate the risk that the rebar inside the concrete slab will be damaged by excavation for installing an anchor or the like.

  Moreover, since the thickened layer formed of this highly elastic resin mortar is also excellent in waterproofness, the penetration of permeated water into the concrete slab can be effectively blocked.

  In the above configuration, the thickness of the thickening layer is not particularly limited, and can be set to an arbitrary thickness according to the required strength. It is preferable to form with a thickness of 35 mm. This is because if the thickness of the thickening layer is less than 5 mm, it is difficult to sufficiently improve the strength by thickening the top surface, and the workability when forming the thickening layer is deteriorated. If the thickness of the layer exceeds 35 mm, the increase in the weight of the concrete slab due to the formation of the thickening layer becomes large, and overcoating is required to form the thickening layer, which is disadvantageous in terms of workability and cost. Is by becoming. From such a viewpoint, it is more preferable to form the thickening layer with a thickness of 10 to 30 mm.

  In the above configuration, if the thickened layer is formed only in a partial region on the upper surface of the concrete floor slab, the traffic regulation required for the thickening of the upper surface can be minimized. In addition, when the concrete slab is composed of prestressed concrete, the effect on the prestress introduced into the concrete slab can be minimized by reducing the application range of the thickening of the upper surface. .

The figure which shows the road bridge used as the application object of the floor slab upper surface thickening construction method which concerns on one Embodiment of this invention in the cross section along the bridge axis orthogonal surface. FIG. 1 is a detailed view of a main part of the upper surface thickening process according to the embodiment. The top view which shows the test body used for the wheel load running test test done in order to confirm the effect of the said embodiment The figure which shows the test apparatus used for the said wheel load running test in the position of the IV-IV sectional view of FIG. The figure which shows the result measured with the strain gauge installed in three places of the above-mentioned specimen by a graph Side sectional view showing the state of an adhesion test performed to confirm the operational effects of the above embodiment The figure similar to FIG. 1 which shows the modification of the said embodiment FIG. 7 is a detailed view of the main part of the upper surface thickening construction process according to the above modification.

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

  FIG. 1 is a view showing a road bridge to which a floor slab upper surface thickening method according to an embodiment of the present invention is applied, in a cross section along a plane orthogonal to the bridge axis.

  In that case, the figure (a) has shown the road bridge 10A before giving the upper surface thickening construction by the floor slab upper surface thickening construction method concerning this embodiment, and the same figure (b) shows this upper surface thickening construction. The road bridge 10B after giving is shown.

  As shown in FIG. 4A, the road bridge 10A before the top surface thickening construction is arranged so as to straddle the upper end surfaces of the plurality of main girders 12 arranged at a predetermined interval in the bridge axis orthogonal direction. The concrete floor slab 14 is arranged.

  The concrete floor slab 14 of the road bridge 10A is formed such that its upper surface 14a extends along a horizontal plane, and a ground cover 14b is formed at both ends of the upper surface 14a in the direction perpendicular to the bridge axis.

  The upper surface 14a of the concrete slab 14 has a width of two lanes. An asphalt pavement 16 is formed on the upper surface 14 a of the concrete slab 14.

  In the present embodiment, in order to cope with an increase in traffic volume in the future for such an existing road bridge 10A (for example, in order to improve the proof stress when the design wheel load increases due to deregulation), concrete is provided. As the whole surface reinforcement of the upper surface 14a of the floor slab 14, the upper surface thickening construction is performed on the entire region.

  As shown in FIG. 2B, in the road bridge 10B after the upper surface thickening work, the thickened layer 20 made of highly elastic resin mortar is formed on the upper surface 14a of the concrete slab 14 over the entire area. Yes.

The thickening layer 20 is formed with a thickness of 5 to 35 mm (for example, a thickness of about 20 mm). The highly elastic resin mortar constituting the thickened layer 20 is a material in which an aggregate such as sand is mixed with a synthetic resin such as an epoxy resin, and the blending ratio of the aggregate is increased as compared with a normal resin mortar. As a result, the Young's modulus becomes a value of 1/3 or more (for example, about 1/2) with respect to the Young's modulus (usually about 30 kN / mm ² ) of the concrete constituting the concrete slab 14. It was prepared.

  And in the road bridge 10B after this upper surface thickening construction, a new asphalt pavement 26 is formed on the upper surface of the thickened layer 20.

  FIG. 2 is a detailed view of the main part of FIG. 1 showing in detail the process of thickening the upper surface according to the present embodiment, wherein FIG. 2 (a) is a detailed view of the IIa part of FIG. FIG. 4D is a detailed view of the IId portion of FIG.

  This upper surface thickening construction is performed in the following steps.

  First, the asphalt pavement 16 is removed from the upper surface 14a of the concrete floor slab 14 in the existing road bridge 10A shown in FIG. At this time, the asphalt pavement 16 is removed from the entire area of the upper surface 14 a of the concrete floor slab 14.

  Next, as shown in FIG. 2B, the upper surface 14a of the concrete slab 14 from which the asphalt pavement 16 has been removed is roughened. This roughening is performed by a water jet or the like. In addition, due to this roughening, the concrete floor slab 14 is slightly reduced in thickness (for example, about 5 mm).

  Then, as shown in FIG. 3C, a thickened layer 20 made of highly elastic resin mortar is formed on the upper surface 14a of the roughened concrete floor slab 14 with a predetermined thickness t (for example, about t = 20 mm). ). The thickening layer 20 is formed on the entire area of the upper surface 14a of the concrete slab 14. Further, the thickening layer 20 is formed by applying a primer to the roughened upper surface 14a of the concrete floor slab 14 and then forming a highly elastic resin mortar with a constant thickness by trowel finishing or rolling. Do.

  Thereafter, as shown in FIG. 4D, a new asphalt pavement 26 is formed on the upper surface of the thickening layer 20 after waterproofing. The asphalt pavement 26 is formed over the entire area of the upper surface 14a of the concrete slab 14.

  Next, the effect of this embodiment is demonstrated.

  In the floor slab upper surface thickening method according to this embodiment, the upper surface 14a of the roughened concrete floor slab 14 has a Young's modulus of 1/3 or more with respect to the concrete constituting the concrete floor slab 14. Since the thickening layer 20 is formed of a highly elastic resin mortar having a value of Young's modulus, the required strength is ensured even when the minimum construction thickness of the thickening layer 20 is set to be relatively thin. be able to. As a result, the degree of bending stress can be reduced. Moreover, since the thickened layer 20 formed of this highly elastic resin mortar is excellent in salt barrier properties, it is possible to eliminate the concern about corrosion of the reinforcing bars and the like inside the concrete slab 14 even in the area where the antifreezing agent is applied. it can.

  As described above, according to the present embodiment, the minimum construction thickness of the thickening layer 20 can be reduced while ensuring the necessary strength as the concrete slab 14, and there is a concern about corrosion even in the region where the antifreezing agent is applied. Can be eliminated.

  Moreover, since the highly elastic resin mortar is also excellent in adhesion properties with concrete, it is possible to ensure the surface integrity of the thickened layer 20 and the concrete floor slab 14 without requiring an anchor or the like. . And thereby, the construction cost for forming the thickening layer 20 can be suppressed low. Moreover, in the concrete slab 14 in which the thickening layer 20 is formed, it is possible to prevent the local concentration of the interfacial shear force from occurring. Further, it is possible to eliminate the possibility that the rebar inside the concrete slab 14 is damaged by excavation for installing an anchor or the like.

  Moreover, since the thickened layer 20 formed of this highly elastic resin mortar is also excellent in waterproofness, the penetration of permeated water into the concrete floor slab 14 can be effectively blocked.

  At this time, in the present embodiment, the thickening layer 20 is formed with a thickness of 5 to 35 mm, so that the increase in the weight of the concrete slab 14 due to the formation of the thickening layer 20 is sufficiently suppressed. Thus, the required strength can be ensured without deteriorating the workability when forming the thickened layer 20.

  If the asphalt pavement 26 is formed with the same thickness as the asphalt pavement 16 in the road bridge 10A before the top surface thickening work in the road bridge 10B after the top surface thickening work, The position is displaced upward from the position of the upper surface of the asphalt pavement 16 in the road bridge 10A before the upper surface thickening work by the thickness increase of the thickening layer 20 after roughening. Since the thickness of the layer 20 is as thin as 5 to 35 mm, the ground cover 14b and the like can be used without any problem at the same height.

  Next, the contents of a test conducted to confirm the operational effects of the present embodiment will be described.

(1) Wheel load running test In this wheel load running test, when the thickened layer 20 is formed on the upper surface 14a of the concrete slab 14, the peeling resistance due to the wheel load fatigue of the reinforcing material constituting the thickened layer 20 is determined. It was carried out for the purpose of verifying.

  In this wheel load running test, three types of reinforcing materials A, B, and C having the characteristics shown in Table 1 were used.

As shown in the table, these three types of reinforcing materials A, B, and C are 1/3 or more with respect to the Young's modulus (usually about 30 kN / mm ² ) of the concrete constituting the concrete floor slab 14. A highly elastic resin mortar having a Young's modulus of the following value was used. Specifically, those having a Young's modulus of 10 kN / mm ² or more were used as the highly elastic resin mortar constituting each of the reinforcing materials A, B, and C.

That is, the reinforcing material A is a material in which silica sand and corundum are mixed as an aggregate in a two-component mixed epoxy resin, and the resin aggregate ratio is set to 1: 6. The compressive strength of the reinforcing material A is 57 kN / mm ² , and its Young's modulus is 13 kN / mm ² .

The reinforcing material B is a material in which a silica sand blend is mixed as an aggregate in a two-component mixed epoxy resin, and the resin aggregate ratio is set to 1: 3.5. Compressive strength of the reinforcement B is 90 kN / mm ^2, the Young's modulus is 17 kN / mm ^2.

The reinforcing material C is a material in which ceramic powder is mixed as an aggregate in a two-component mixed epoxy resin, and the resin aggregate ratio is set to 1: 5. Compressive strength of the reinforcement C is 110kN / mm ^2, the Young's modulus is 19kN / mm ^2.

  FIG. 3 is a plan view showing a test body 50 used in the wheel load running test.

  In this test body 50, after the upper surface 54a of the concrete floor slab 54 extending in the bridge axis direction is roughened at a plurality of locations, three types of reinforcing materials A, B, and C are formed as thickening layers at each location. It has become the composition.

  At that time, each of these reinforcing materials A, B, and C was formed so as to be flush with the position of the original upper surface 54a with two thicknesses of 10 mm and 30 mm, respectively. In the figure, these are indicated by A (10), A (30), B (10), B (30), C (10), and C (30).

  These six kinds of reinforcing materials A (10), A (30), B (10), B (30), C (10), and C (30) are formed in a rectangular shape extending in the direction perpendicular to the bridge axis. And arranged in series in this order at a predetermined interval in the bridge axis direction. At that time, the healthy floor slab D was set as a region where the reinforcing material was not formed on the upper surface 54a of the concrete floor slab 54 between the reinforcing material B (30) and the reinforcing material C (10).

  In addition, since the reinforcing material A has many aggregate components, when forming this as a thickening layer, a trowel finish was difficult and the finishing by the compactor was required. Although the reinforcing material B was viscous, it could be constructed with a trowel finish. The reinforcing material C has a high viscosity, and an electric iron is necessary for finishing the iron when forming the reinforcing material C as a thickened layer.

  In this test body 50, a PC floor slab in which prestress by a plurality of PC steel bars 52 was introduced to reinforced concrete was used as the concrete floor slab 54. At that time, the plurality of PC steel bars 52 were arranged so as to extend in a direction perpendicular to the bridge axis at a predetermined interval in the bridge axis direction.

  FIG. 4 is a view showing the test apparatus 60 used in the wheel load running test at the position of the section taken along the line IV-IV in FIG.

  As shown in the figure, in this test apparatus 60, a pair of steel members 62 extending in the bridge axis direction and arranged at a predetermined interval in the direction orthogonal to the bridge axis are arranged at a predetermined interval in the bridge axis direction. It is mounted on a plurality of steel members 64 extending in the direction perpendicular to the bridge axis. Further, the test body 50 is arranged horizontally so as to be bridged between the pair of steel materials 62. The wheel load running test machine 70 reciprocates in the direction of the bridge axis in the center area in the direction perpendicular to the bridge axis on the upper surface of the test body 50 (the area indicated by a pair of two-dot chain lines in FIG. 3). . At this time, the wheel load running test machine 70 runs while being suspended and supported by an upper rail 66 disposed above the test body 50.

  In the test apparatus 60, a rubber tire self-propelled system capable of reproducing actual bearing conditions was used as the wheel load running test machine 70. In the actual road bridge 10B shown in FIG. 1B, the bearing pressure is relieved by the influence of the asphalt pavement 26 laid on the upper surface 14a of the concrete floor slab 14, but this effect is excluded. In order to perform the test under severe conditions, the rubber tire 72 of the wheel load running tester 70 was placed on the upper surface 50a of the test body 50 without running asphalt pavement.

  The specific contents of the wheel load running test and the test results are as follows.

  That is, in this wheel load running test, the vehicle was run 100,000 times with a wheel load of 100 kN, but no abnormalities such as peeling and cracking were detected from the results of hammering inspection, strain measurement, and the like. For this reason, the wheel load is increased to 120 kN and 10,000 runs are added, and the wheel load is increased to 140 kN and 40,000 runs are added, and fatigue tests are performed for a total of 150,000 runs. Carried out.

  During the wheel load running test, the wheel load running was stopped several times and the loading test was carried out statically. At that time, the strain was measured with strain gauges installed at a total of three locations, that is, the upper surface 54a of the concrete floor slab 54 and the upper side and the lower side of the reinforcing bars disposed therein.

  FIG. 5 is a graph showing the results of measurement with strain gauges installed at these three locations. In that case, the same figure (a) is a graph which shows the result of having measured the distortion before a run, and the same figure (b) is the graph which shows the result of having measured the distortion after 150,000 times of run.

  As is clear from the figure, even after traveling 150,000 times, the strain distribution has hardly changed from that before traveling. From this result, it was confirmed that the structural performance after forming the thickened layer was not impaired by fatigue.

  Moreover, after this wheel load running test was completed, the reinforcing materials A, B, and C were cut, and in this state, an adhesion test (Kenken type 40 × 40 mm) was performed.

  The results of this adhesion test are shown in Table 2.

  As is clear from the table, in any of the three types of reinforcements A, B, and C, make sure that no separation occurs at all after the wheel load running test as well as before the wheel load running test. I was able to.

(2) Adhesion test with waterproofer This adhesion test is carried out by the thickening layer 20 formed on the upper surface 14a of the concrete slab 14, and the waterproofing applied between the thickening layer 20 and the asphalt pavement 26. This was carried out for the purpose of verifying the adhesiveness with the work.

  FIG. 6 is a side sectional view showing the state of the adhesion test.

  As shown in the figure, this adhesion test is performed by applying a waterproofing work 58 and asphalt pavement 56 to the test body 50 for which the wheel load running test has been completed, and then removing a test piece 50A cut out with a predetermined width. The shear strength is measured by applying a shearing force between the reinforcing materials A, B, and C formed on the upper surface 54a of the concrete floor slab 54 and the asphalt pavement 56 to the specimen 50A. did.

  The results of this adhesion test are shown in Table 3.

  As is apparent from the table, it was confirmed that the shear strength of the three types of reinforcing materials A, B, and C satisfied the standard value.

(3) Fire resistance test This fire resistance test is a highly elastic material that forms the thickened layer 20 in the event of a fire in the upper surface 14a of the concrete slab 14 immediately above the portion where the thickened layer 20 is formed. Since the resin mortar contains an organic component, there is a concern about dissolution of the resin component and combustion loss due to ignition.

  In this fire resistance test, the surface of the asphalt pavement 56 of the test body 50 was burned at 600 to 800 ° C. for 30 minutes with a gas burner. As a result, in any of the reinforcing materials A, B, and C, the temperature increase was only 90 ° C., and no resin dissolution or material separation occurred.

  As a result of performing a temperature analysis simulation to reproduce this fire resistance performance test, the surface temperature of each of the reinforcing materials A, B, and C remains at 300 ° C. even after 3 hours have passed since the combustion was further performed. It could be confirmed that the reinforcing materials A, B, and C did not reach 400 to 500 ° C. where they burned.

  From the test results of (1) to (3) above, a highly elastic resin mortar (for example, reinforcement) whose Young's modulus is set to a value of 1/3 or more of the Young's modulus of the concrete constituting the concrete floor slab 14 In the case where the thickened layer 20 is formed with any one of the materials A, B, and C), and the thickened layer 20 is formed with a thickness within the range of 10 to 30 mm, at least the effects of the present embodiment. Was confirmed to be obtained with certainty. From the above test results, it can be easily estimated that the effects of the present embodiment can be obtained even when the thickening layer 20 is formed with a thickness in the range of 5 to 35 mm.

  In the above embodiment, the upper layer of the thickening layer 20 has been waterproofed, and the new asphalt pavement 26 is formed. However, the thickening layer 20 is a highly elastic resin excellent in waterproofness. Since it is formed of mortar, the waterproofing can be omitted, or the waterproofing can be applied only to the joint.

  Next, a modification of the above embodiment will be described.

  FIG. 7 is a view showing a road bridge to which the floor slab upper surface thickening method according to this modification is applied, in a cross section along the plane orthogonal to the bridge axis.

  In this case, FIG. 10A shows the road bridge 110A before the upper surface thickening work by the floor slab upper surface thickening method according to this modification, and FIG. The road bridge 110B after giving is shown.

  As shown in FIG. 5A, the road bridge 110A before the top surface thickening work is a road bridge just before the construction work is completed, and is provided at a plurality of locations (two locations) on the top surface 14a of the concrete floor slab 14. A local depression 14a1 is generated. These depressions 14a1 can be generated during construction of the concrete floor slab 14 for reasons such as construction problems. When such a recess 14a1 is generated, the concrete floor slab 14 is partially insufficient in thickness, so that a predetermined floor slab thickness cannot be secured.

  Therefore, in this modified example, the concrete floor slab 14 of the road bridge 110A is subjected to top surface thickening as partial reinforcement at a plurality of locations corresponding to the depressions 14a1 generated on the top surface 14a, thereby improving the proof stress. It is designed to be illustrated.

  The basic structure of the concrete floor slab 14 and the main girder 12 constituting the road bridge 110A is the same as that in the above embodiment.

  As shown in FIG. 4B, in the road bridge 110B after the top surface thickening work, a thickened layer 120 made of highly elastic resin mortar is partially formed at a plurality of locations on the top surface 14a of the concrete floor slab 14. Has been.

  The thickening layer 120 at each location is formed with a thickness of 5 to 35 mm (for example, a thickness of about 20 mm), similar to the thickening layer 20 of the above embodiment. At that time, the composition of the highly elastic resin mortar constituting the thickening layer 120 is the same as that of the thickening layer 20 of the above embodiment.

  FIG. 8 is a detailed view of the main part of FIG. 7 showing in detail the process of thickening the upper surface according to this modification, wherein FIG. 8 (a) is a detailed view of the VIIIa part of FIG. FIG. 7C is a detailed view of the part VIIIc in FIG.

  This upper surface thickening construction is performed in the following steps.

  First, as shown in FIG. 4A, a concrete floor slab 14 having depressions 14a1 formed at a plurality of positions on the upper surface 14a is formed on the upper surface 14a thereof as shown in FIG. In each of the plurality of locations, the bottom surface 14a2 is roughened after the surface is shaved horizontally over a range slightly wider than the outer peripheral edge of the recess 14a1 to a depth substantially equal to the depth of the recess 14a1. This roughening is performed by a water jet or the like. At that time, since the recess 14a1 that can be generated on the upper surface 14a during the construction of the concrete floor slab 14 is not so deep, the amount of cutting of the upper surface 14a of the concrete floor slab 14 is the bottom surface 14a2 where the amount of cutting is maximized. Also at the outer peripheral edge, it is possible to set the depth to about 5 to 35 mm.

  Thereafter, as shown in FIG. 2C, the thickened layers 120 made of highly elastic resin mortar are respectively formed on the bottom surface 14a2 of the concrete floor slab 14 that is horizontally cut and roughened at a plurality of locations. At this time, the thickening layer 120 is formed so as to have a thickness (that is, about 5 to 35 mm) that is flush with the upper surface 14a of the surrounding concrete floor slab 14. The thickening layer 120 is formed by applying a primer to the bottom surface 14a2 of the roughened concrete floor slab 14 and then forming a highly elastic resin mortar with a constant thickness by trowel finishing or rolling. Do.

  Even when the floor slab upper surface thickening method according to this modification is adopted, the minimum construction thickness of the thickened layer 120 is reduced after securing the necessary strength as the concrete slab 14 as in the case of the above embodiment. It is possible to reduce the thickness and eliminate the concern of corrosion even in the area where the antifreezing agent is applied.

  Moreover, as in this modification, the thickened layer 120 is formed only in a partial region on the upper surface 14a of the concrete floor slab 14 to reduce the application range of the upper surface thickening work, so that the concrete floor slab 14 is prestressed concrete. In the case where it is configured, the influence on the prestress introduced into the concrete slab 14 can be minimized.

  In addition, in the said modification, although the case where the object of upper surface thickening construction was the road bridge 110A just before completion of construction work was demonstrated, it is a partial area | region in the upper surface of the concrete floor slab with respect to the existing road bridge. It is also possible to form a thickened layer only. And when it does in this way, the traffic regulation required with the upper surface thickening construction can be suppressed to the minimum.

  In the said embodiment and modification, although the case where the upper surface 14a of the concrete floor slab 14 had the width for two lanes was demonstrated, in the case other than this, it is the same as that of the said embodiment or modification By performing the upper surface thickening construction, the same effects as these can be obtained.

  Moreover, in the said embodiment and modification, road bridge 10A, 110A used as the object of upper surface thickening construction has the upper structure by which the concrete floor slab 14 is arrange | positioned at the upper end surface of the some main girder 12. FIG. Although described as a thing, it is applicable also when it has an upper structure other than this.

  In addition, the numerical value shown as a specification in the said embodiment and modification is only an example, and of course, you may set these to a different value suitably.

10A, 10B, 110A, 110B Road bridge 12 Main girder 14, 54 Concrete floor slab 14a, 54a Top surface 14a1 Depression 14a2 Bottom surface 14b Ground cover 16, 26, 56 Asphalt pavement 20, 120 Thickening layer 50 Specimen 50A Specimen piece 52 PC steel bar 58 Waterproofing work 60 Test equipment 62, 64 Steel 66 Upper rail 70 Wheel load running test machine 72 Rubber tires A, A (10), A (30), B, B (10), B (30), C, C (10), C (30) Reinforcement material D Healthy floor slab

Claims (3)

In the floor slab upper surface thickening method to increase the upper surface of the concrete floor slab in order to reinforce the concrete floor slab of the road bridge,
After roughening the upper surface of the concrete floor slab, the upper surface of the roughened concrete floor slab is a Young whose value is 1/3 or more of the Young's modulus of the concrete constituting the concrete floor slab. A method for increasing the thickness of an upper surface of a floor slab, comprising forming a thickened layer with a highly elastic resin mortar having a modulus.   The floor slab upper surface thickening method according to claim 1, wherein the thickened layer is formed with a thickness of 5 to 35 mm.   The floor slab upper surface thickening method according to claim 1 or 2, wherein the thickened layer is formed only in a partial region on the upper surface of the concrete floor slab.

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