JPH06307085A - Execution method for jointing part of successively placed concrete of very high strength structure - Google Patents

Abstract

PURPOSE:To improve strength of a successively concrete placing part by preventing cracks at the time of curing very high strength concrete after placing, cracks due to heat of hydration and lowering of adhesive force. CONSTITUTION:A recessed and projecting part 7 of a cover 6 is pressed onto the upper end surface of a column 2 of very high strength concrete to form a recessed and projecting part, and/or jointing surface curing water is filled on the upper end surface 5. After suitable curing time elapses, the jointing surface curing water is removed. The surface dried saturated upper end surface 5 is formed to perform execution of jointing for a column 2a of very high strength concrete.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an ultra-high strength concrete structure, and more particularly to an ultra-high-strength concrete structure which is suitable for improving the adhesiveness of the joint and ensuring the strength. Regarding the construction method of parts.

[0002]

2. Description of the Related Art Water-cement ratio is 30 for ultra-high strength concrete having a design standard strength of 600 [kg / cm ² ] or more.
[%] Or less, and the unit cement amount is 500 [kg / c
m ³ ] or more. The structure is completed by driving such super-high-strength concrete into the formwork and sequentially splicing it. However, if the strength of the splicing part is insufficient or cracks occur, the strength of the structure will decrease, so Special attention was required for the in-situ casting method of high strength concrete.

On the other hand, as a publicly known technique for preventing the deterioration of the strength and quality of concrete, Japanese Patent Laid-Open No. 2-30064.
No. 6, Japanese Patent Publication No. 4-75979, and Japanese Unexamined Patent Publication No.
No. 7-135785 is cited. Japanese Patent Laid-Open No. 2-3
Japanese Patent Publication No. 00466 discloses a “method for controlling the strength of a concrete structure”, and the description thereof discloses a technique of covering concrete with a heat insulating material immediately after placing.
Further, Japanese Patent Publication No. 4-75979 discloses a technology of pressurizing a concrete placing surface with a pressurizing plate in order to prevent insufficient strength of the upper part of a high-strength concrete pillar. There is. Further, JP-A-57-135785 discloses a technique of curing concrete after pouring with warm water instead of boiler steam.

[0004]

The method of placing super-high strength concrete generally has the following problems. First,
Cracking occurs due to hydration shrinkage of cement. Also,
Cracking occurs on the driving surface due to temperature stress due to heat of hydration and rapid drying. In addition, when the concrete is hardened and then the jointing is performed or when the jointing surface is smooth, the adhesive strength of the jointing surface is low, and the shear strength cannot be expected. Due to the above problems, the conventional super high-strength concrete placing method requires special caution and skill in construction, but it is difficult to completely solve the above problems.

On the other hand, those disclosed in the above-mentioned known art are effective in reducing the strength and curing of concrete, but are hardly effective in preventing the cracks in the splice joint and in reducing the adhesive strength.

The present invention was devised in view of the above circumstances, and prevents the splicing joint from drying, prevents cracking due to hydration shrinkage, and prevents cracking due to heat of hydration and improves the adhesive strength. An object of the present invention is to provide a method for constructing a splicing part of an ultra-high-strength concrete structure that improves and enables high-strength splicing.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention strikes a super-high-strength concrete pillar of an upper floor on the upper end surface of a super-high-strength concrete pillar that is driven into a formwork. In a construction method for forming an ultra-high-strength concrete structure while splicing, after pressing a lid having an uneven portion on the upper end surface and / or applying a vibration to form convex and concave portions on the upper end surface, the lid is It is characterized by the construction method of the splicing part of the ultra-high-strength concrete structure that was removed to splice the super-high-strength concrete on the upper floor. In addition, a piling seam form of an appropriate depth is provided at a position surrounding the periphery of the upper end surface of the boundary part of the ultra-high strength concrete pillar and the ordinary strength concrete beam connected to it, and the pour seam surface curing is performed in the mold. After injecting water and removing the curing water for the splicing surface after an appropriate time, and wiping it off to make the upper surface of the surface dry and saturated so that the super-high-strength concrete structure of the upper floor can be spliced. It features the construction method of the splice part. Furthermore, while forming a convex-concave portion on the upper end surface of the ultra-high-strength concrete, pour joint surface curing water is injected into the piling joint mold surrounding the periphery of the upper end surface, and the pour joint surface curing water after an appropriate time has elapsed. It is characterized by a method of constructing a jointing portion of an ultra-high-strength concrete structure in which the upper end surface is subjected to surface dry saturation to wipe out the super-high-strength concrete structure on the upper floor.

[0008]

After the super high-strength concrete is cast into the form, the upper end surface of the concrete is pressed by the lid having the uneven portions to form the convex and concave portions.
Thereby, the adhesive force can be improved. Further, by covering the upper end surface with the lid for a certain period of time, sudden drying can be prevented. On the other hand, by pouring water on the upper end surface, it is possible to cool the concrete whose temperature rises due to the intense heat of hydration of ultra-high strength concrete, prevent sudden drying, and improve the hydration water absorption curing effect. The strength can be improved. Furthermore, the combined use of the formation of the projections and depressions and the water filling further enhances the effect. Further, after water filling, the upper end surface is wiped to make the surface dry and saturated, so that the strength of the splicing portion can be further improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view for explaining an embodiment using a lid of the present invention, FIG. 2 is a partial axial sectional view of the embodiment, FIG. 3 is a top view of FIG. 2, and FIGS. 6 is a partial axial sectional view showing a pressing means of the lid, FIG. 6 is a partial axial sectional view showing an embodiment of the present invention which is water-filled, FIG. 7 is a top view thereof, and FIG. 8 is a lid and water-filled present invention 9 is a partial axial sectional view showing the embodiment of FIG. 9, FIG. 9 is a top view of FIG. 8, and FIG.

As shown in FIG. 1, the mold 1 for the lower pillar
Ultra-high-strength concrete with a plurality of reinforcing bars 3 buried therein is driven into. A beam 4 made of ordinary strength concrete is connected around a column 2 of ultra high strength concrete. A lid 6 is temporarily fixed to the reinforcing bar 3 protruding from the upper end surface 5 of the column 2 of ultra high strength concrete. Further, as shown in FIGS. 2 and 3, the lid 6 is provided with an uneven portion 7 having an appropriate shape.
On the other hand, as shown in FIG. 2, the support plate 8 is fixed to the reinforcing bar 3. As shown in FIG. 2, the lid 6 having the concave-convex portion 7 is pressed against the upper end surface 5 before the ultra-high-strength concrete that is cast into the mold 1 is cured. As a result, a convex-concave portion 9 opposite to the concave-convex portion 7 is formed on the upper end surface 5.

As means for pressing the lid 6 toward the upper end surface 5 side, a pressing tool which will be described later is used, or the lid 6 is vibrated by hitting the lid 6 or a means (not shown) to vibrate the upper end surface of the lid 6. The one that is pressed against the 5 side is adopted.

FIG. 4 shows an example of a pressing tool, in which the jack 10 is interposed between the lid 6 and the support plate 8 and the lid 6 is pressed toward the upper end surface 5 side with the support plate 8 as a base point. Also,
In FIG. 5, a bolt 11 is installed between the flange portion 1a of the mold 1 and the lid 6, and the lid 6 is pressed against the upper end surface 5 side by tightening the bolt 11.

Next, another embodiment of the present invention will be shown. As shown in FIGS. 6 and 7, in this embodiment, water is applied to the upper end surface 5 of the cast-in-place concrete column 2 for curing. At the boundary between the columns 2 of ultra-high strength concrete and the beams 4 of normal-strength concrete, a splicing form 12 is arranged so as to surround the periphery of the upper end surface 5 of the columns 2 of ultra-high strength concrete. This piecing formwork 12 is, for example, a wire net embedded in the column 2 of ultra-high-strength concrete over the entire cross section of the beam and floor slab, and the portion protruding from the upper end surface 5 has a height of about 50 [mm]. Formed from a water-blocking material. On the upper end surface 5 of the column 2 of ultra-high-strength concrete surrounded by the casting joint frame 12, the casting joint surface curing water 13 is injected and filled. The splice surface curing water 13 is stretched for about 12 to 48 hours after concrete is poured, and is removed after a lapse of time. The upper end surface 5 from which the splicing surface curing water 13 has been removed needs to be kept in a surface dry saturated state immediately before pouring concrete on the upper floor. The surface dry saturated state is a state in which the surface is wet with water but does not shine visually, and this state is the surface state having the best concrete adhesion.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. This embodiment is a combination of the embodiment shown in FIG. 2 and the embodiment shown in FIG. That is,
A convex portion 9 is formed by a lid 6 on the upper end surface 5 of the column 2 of ultra high strength concrete. Further, the splicing surface curing water 13 is spread on the upper end surface 5 surrounded by the splicing form frame 12. The convex and concave portions 9 are formed and the splice surface curing water 13
The upper end surface 5 which has been removed to form the surface dry saturated state has a surface shape that further improves the splicing strength.

FIG. 10 shows a state in which an ultra-high strength concrete column 2a (shown in FIG. 1) is spliced onto an ultra-high strength concrete column 2 formed by the construction method of the above embodiment. The super-high-strength concrete pillar 2a has a sufficient adhesive force due to the surface dry-saturated surface shape formed by projections and depressions 9 and / or water filling formed on the upper end surface 5 of the super-high-strength concrete pillar 2 on the lower side. To form a splice joint having high shear strength. In addition, cracks and the like do not occur even during the construction, and it is possible to form an ultra-high-strength column as a whole.

In the above description, the shape of the convex / concave portion 9 formed by the lid 6 is not limited to that of the embodiment. Further, the shape of the splicing form 12 is not limited to that of the embodiment, and the capacity and the curing time of the splicing surface curing water 13 are not limited to the above contents.

[0017]

According to the present invention, the following remarkable effects are obtained. 1) Since the upper end surface of the super-high-strength concrete after driving is pressed by the concave and convex portions of the lid to form the convex and concave portions, the adhesiveness of the splicing joint portion is improved and the adhesive force can be improved. 2) Since the lid is pressed against the upper end surface, air bubbles mixed in on the upper end surface side at the time of construction are removed, and a decrease in column strength on the upper end surface side is prevented. 3) After driving, curing is performed by covering the upper end surface side with a lid for an appropriate period of time, so rapid drying is prevented and cracking due to hydration shrinkage is prevented. 4) After the driving, the splicing surface curing water is stretched on the upper end surface for a proper time for curing, so that the heat of hydration is absorbed and cracking is prevented. 5) By removing the water stretched on the upper end surface and wiping it off to form a surface in a surface dry saturated state, it is possible to form a splicing portion having adhesiveness and high strength. 6) It is a relatively simple construction method and is easily applied in on-site construction.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a splicing portion of the present invention.

2 is a partial axial cross-sectional view showing a shape state of an uneven portion on an upper end surface of a column of ultra-high-strength concrete with a lid in the embodiment of FIG.

FIG. 3 is a top view of FIG.

FIG. 4 is a partial axial sectional view showing an embodiment of a lid pressing tool.

FIG. 5 is a partial axial sectional view showing an embodiment of a lid pressing tool.

FIG. 6 is a partial axial cross-sectional view showing a splicing surface curing water stretched in a splicing form on the upper end surface.

FIG. 7 is a top view of FIG.

FIG. 8 is a partial axial cross-sectional view showing the convex-concave portions formed on the upper end surface and the splicing surface curing water.

9 is a top view of FIG.

FIG. 10 is a partial axial cross-sectional view showing a jointing structure of columns of ultra-high-strength concrete on which the construction of this embodiment has been performed.

[Explanation of symbols]

 1 Formwork 1a Flange part 2 Ultra-high-strength concrete pillar 2a Ultra-high-strength concrete pillar 3 Reinforcing bar 4 Beam 5 Upper end surface 6 Lid 7 Uneven portion 8 Support plate 9 Convex recess 10 Jack 11 Bolt 12 Splicing formwork 13 Splicing Masking water

Claims (3)

[Claims] 1. A construction method for forming an ultra-high-strength concrete structure while splicing another ultra-high-strength concrete pillar on the upper end surface of the ultra-high-strength concrete pillar that has been cast into a formwork, It is characterized in that after the convex and concave portions are formed on the upper end surface by pressing the lid having the uneven portion on the upper end surface and / or applying vibration, the lid is removed and the super high-strength concrete of the upper floor is spliced. Construction method of jointing part of ultra high strength concrete structure. 2. An ultrahigh-strength concrete column, a beam of ordinary-strength concrete that is connected to the column, and a splicing formwork having an appropriate depth at a position surrounding the peripheral edge of the upper end surface of the boundary portion, and striking on the upper end surface. Ultra high-strength, characterized in that the splicing surface curing water is removed after an appropriate time after the splicing surface curing water is injected, and the upper end surface is surface-dried and saturated to wipe out the super high-strength concrete of the upper floor. Construction method for joints of high-strength concrete structures. 3. An ultrahigh-strength concrete is formed with convex and concave portions on the upper end surface thereof, and a piecing surface curing water is injected into the piecing joint form frame surrounding the peripheral edge of the upper end surface, and after a lapse of time, the piecing joint is formed. A method for constructing a splicing portion of an ultra-high-strength concrete structure, characterized in that the surface curing water is removed and wiped off to make the upper end surface a surface dry saturated state and splicing the super-high-strength concrete of the upper floor.