JP4781303B2 - Adjustment ring - Google Patents

Description

  The present invention relates to a reinforcing steel reinforced hydraulic hardened body in which reinforcing bars are arranged in a hydraulic hardened body containing cement or the like.

Conventionally, as a structural reinforcing bar used for reinforcing concrete in construction or civil engineering work, a deformed steel bar having a higher resistance to adhesion and pull-out force than concrete is often used compared to a simple round steel bar. This deformed steel bar has a plurality of node-like protrusions (nodes) arranged so as to extend in the circumferential direction at regular intervals in the axial direction of the steel bar, and the outer surface of the steel bar having a predetermined diameter, A plurality of (usually two) long protrusions (ribs) are integrally formed so as to extend in the axial direction (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-228551

The deformed steel bar used as the structural reinforcing bar (reinforcing steel bar) has a length / diameter ratio above a certain value (in order to achieve the reinforcing effect of concrete) According to this, at least 40 or more) is required. For example, the above-mentioned document describes that a deformed steel bar has a diameter of about 10 mm to several tens of mm and a length of 7 to 8 m. In this case, the length / diameter ratio exceeds 100. Is.
However, a deformed steel bar having a large length / diameter ratio has a problem that a relatively long reinforcing bar is arranged in the concrete, resulting in an increase in the mass of the concrete structure.

By the way, as a concrete structure used in civil engineering work, for example, an adjustment ring or the like for constructing a manhole neck structure is known.
As shown in FIG. 10, the adjustment ring 60 is configured to adjust the height of the cover receiving frame 64 that supports the manhole cover 65 so that the manhole cover 65 forms an upper surface that is flush with the ground surface A. It is placed on the upper end surface (upper floor slab) 62a of the manhole block 62 that constitutes the wall surface of the vertical hole 61 formed therein.
As shown in FIG. 10, the conventional manhole neck structure is formed by stacking the adjustment ring 60 on the upper floor slab 62 a, and further overlapping the neck adjustment member 63 for adjusting the height on the adjustment ring 60, A lid receiving frame 64 made of cast iron or the like is placed on the neck adjustment member 63, and a manhole cover 65 made of cast iron or the like is placed on the lid receiving frame 64. The lid receiving frame 64 is fixed to the adjustment ring 60 by a receiving frame fixing bolt 66 inserted through the flange portion 64 a of the lid receiving frame 64 and the neck adjustment member 63.
The adjustment ring used to place the manhole cover whose diameter is smaller than the diameter of the vertical hole of the manhole is from the upper floor board of the manhole block constituting the wall surface of the vertical hole of the manhole toward the center of the vertical hole. With the adjustment ring protruding, it is stacked on the upper floor board of the manhole block. A manhole cover is placed on the adjustment ring in such a state. When a passing vehicle passes over the manhole cover and a large load is applied from above, the adjustment ring that supports the manhole cover is such that the portion of the adjustment ring protruding from the manhole block has a large load from above. It becomes easy to be destroyed by. Therefore, it is desired that the adjustment ring be further reduced in size while improving the reinforcing effect so as not to be broken even when a manhole cover having a diameter smaller than the diameter of the vertical hole of the manhole is supported.

Accordingly, the present invention consists Reinforced hydraulic cured body formed by Haisuji profiled bars into the hydraulic hardening material such as concrete, even a small ratio of length / diameter of the deformed steel bars than conventional, it can exhibit the reinforcing effect, and to provide an adjustment ring for supporting a smaller manhole cover in diameter than the diameter of the longitudinal hole of the manhole.

As a result of intensive studies to solve the above problems, the inventor of the present invention uses a specific hydraulic compound, so that even when a deformed steel bar having a smaller length / diameter ratio is used than before. The present inventors have found that the reinforcing effect of the deformed steel bar can be exerted, and as a result, the adjustment ring for supporting the manhole cover can be thinned, and the present invention has been completed.
That is, the present invention provides the following [1] to [ 6 ].

[1] Adjusting ring for supporting the manhole cover, (A) 100 parts by mass of cement with a specific surface area of Blaine of 2,500 to 5,000 cm ² / g, (B) Silica fume, silica dust, fly ash, slag, volcanic ash A composition comprising 10 to 40 parts by mass of fine particles having a BET specific surface area of 5 to 25 m ² / g, (C) fine aggregate, (D) a water reducing agent, and (E) water, comprising silica sol or precipitated silica In the ring-shaped hydraulic hardened body comprising one or more ring-shaped long reinforcing bars concentric with the hydraulic hardened body, the ring-shaped long reinforcing bars are spaced at equal intervals in the circumferential direction, An adjustment ring comprising a short reinforcing bar made of deformed steel bar having a length / diameter ratio of 5 to 20 and arranged so as to intersect substantially vertically with the long reinforcing bar.
[ 2 ] The adjustment ring according to [1] , wherein the blend includes (F) inorganic particles having a Blaine specific surface area of 2,500 to 30,000 cm ² / g and having a Blaine specific surface area larger than that of the cement.
[3] described above inorganic particles (F) are inorganic particles A of Blaine specific surface area 5,000~30,000cm ² / g, the comprising an inorganic particles B of Blaine specific surface area 2,500~5,000cm ² / g ^[2] Adjustment ring.
[ 4 ] The adjustment ring according to any one of [1] to [ 3 ], wherein the blend includes (G) one or more fibers selected from the group consisting of metal fibers, organic fibers, and carbon fibers.
[ 5 ] The adjustment ring according to any one of [1] to [ 4 ], wherein the blend comprises (H) fibrous particles or flaky particles having an average particle size of 1 mm or less.
[ 6 ] The adjusting ring according to any one of [1] to [ 5 ], wherein the compressive strength of the hydraulic cured body is 100 N / mm ² or more.

According to the present invention, since a specific hydraulic compound is used, even if a deformed steel bar having a smaller length / diameter ratio than before is used, the hydraulic hardened body is reinforced by the deformed steel bar. The effect can be exhibited, and as a result, the weight of the adjusting ring made of the reinforcing steel reinforced hydraulic hardened body for supporting the manhole cover can be reduced.
In addition, according to the present invention, it is possible to use the shaped bar as a straight short rod-like body for the application of the adjusting ring without forming hooks at both ends provided in the conventional shaped bar. .
According to the present invention, since the main body is formed of a cement-based compound, the degree of freedom in designing the shape is large, and a product can be easily manufactured in a short time.
Furthermore, according to the present invention, an optimal product according to required mechanical strength, service life and cost is manufactured by appropriately determining the composition of the composition, the length, position, number, etc. of reinforcing bars. be able to.

The adjustment ring of the present invention is not easily cracked or damaged for a long period of time, and can ensure a long service life.

The adjustment ring of the present invention is an adjustment ring for supporting a manhole cover, comprising: (A) 100 parts by mass of cement having a specific surface area of Blaine of 2,500 to 5,000 cm ² / g, and (B) silica fume, silica dust, fly ash , Slag, volcanic ash, silica sol, or precipitated silica, 10-40 parts by mass of fine particles with a BET specific surface area of 5-25 m ² / g, (C) fine aggregate, (D) water reducing agent, and (E) water In the ring-shaped hydraulic hardened body made of a composition containing , one or more ring-shaped long reinforcing bars concentric with the hydraulic hardened body, and at equal intervals in the circumferential direction of the ring-shaped long reinforcing bars , arranged so as to cross substantially perpendicularly to the ring-shaped long rebar, in which the ratio of length / diameter is the short reinforcing bars, which are reinforcement consisting of 5-20 deformed steel bars.
Examples of the cement used in the present invention include various Portland cements such as ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, and low heat Portland cement.
In the present invention, when trying to improve the early strength of the hydraulic cured body, it is preferable to use early-strength Portland cement, and to improve the fluidity of the composition before curing of the hydraulic cured body. In this case, it is preferable to use medium heat Portland cement or low heat Portland cement.

The brane specific surface area of the cement is 2,500 to 5,000 cm ² / g, preferably 3,000 to 4,500 cm ² / g. When the value is less than 2,500 cm ² / g, the hydration reaction becomes inactive, and it is difficult to obtain a compressive strength of 100 N / mm ² or more, and a deformed steel bar having a length / diameter ratio of less than 40 is used. There are drawbacks such as it becomes difficult to use as structural reinforcing bars, and if it exceeds 5,000 cm ² / g, it takes time to grind the cement, and the amount of water to obtain the prescribed fluidity increases, There are drawbacks such as an increased shrinkage after curing.

The fine particles used in the present invention, silica fume, silica dust, fly ash, slag, ash, silica sol or precipitated silica are used.
In general, silica fume and silica dust have a BET specific surface area of 5 to 25 m ² / g and do not need to be pulverized, and thus are suitable as the fine particles of the present invention.

The BET specific surface area of the fine particles is 5 to 25 m ² / g, preferably 8 to 15 m ² / g. When the value is less than 5 m ² / g, it is difficult to obtain a compressive strength of 100 N / mm ² or more because the packing property of the particles constituting the composition lacks denseness, and when it exceeds 25 m ² / g, Since the amount of water to obtain the specified fluidity increases, it is difficult to obtain a compressive strength of 100 N / mm ² or more. There are disadvantages such as it becomes difficult to use deformed steel bars with a diameter ratio of less than 40 as structural reinforcing bars.
The compounding amount of the fine particles is 10 to 40 parts by mass, preferably 20 to 40 parts by mass with respect to 100 parts by mass of cement. When the blending amount is out of the range of 10 to 40 parts by mass, the fluidity is extremely lowered.

Examples of the fine aggregate used in the present invention include river sand, land sand, sea sand, crushed sand, silica sand, and the like, or a mixture thereof.
It is preferable to use a fine aggregate having a particle size of 2 mm or less. Here, the particle size of the fine aggregate is an 85% mass cumulative particle size. If the particle size of the fine aggregate exceeds 2 mm, the mechanical properties after hardening are not preferred.
Further, it is preferable to use a fine aggregate having a content of particles of 75 μm or less of 2.0% by mass or less. When the content exceeds 2.0% by mass, the fluidity of the blend is extremely lowered and the workability is inferior. Further, from the viewpoint of fluidity and workability, it is more preferable to use a fine aggregate having a particle content of 75 μm or less of 1.5% by mass or less.

In the present invention, it is preferable to use a fine aggregate having a maximum particle size of 2 mm or less, and more preferably a fine aggregate having a maximum particle size of 1.5 mm or less from the standpoint of strength development after hardening.
The amount of fine aggregate blended is preferably 30 to 200 parts by weight with respect to 100 parts by weight of cement from the viewpoint of workability of the blend and mechanical strength after curing, reducing self-shrinkage and drying shrinkage, From the viewpoint of reducing the amount of hydration heat, etc., it is preferably 40 to 190 parts by mass, particularly 50 to 180 parts by mass.

As the water reducing agent, a lignin-based, naphthalenesulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent, an AE water reducing agent, a high-performance water reducing agent, or a high-performance AE water reducing agent can be used. Among these, it is preferable to use a high performance water reducing agent or a high performance AE water reducing agent having a large water reducing effect, and it is particularly preferable to use a polycarboxylic acid-based high performance water reducing agent or a high performance AE water reducing agent.
The blending amount of the water reducing agent is preferably 0.1 to 4.0 parts by mass, more preferably 0.3 to 2.0 parts by mass in terms of solid content with respect to 100 parts by mass of cement. If the blending amount is less than 0.1 parts by mass, kneading becomes difficult, the fluidity of the blend is extremely lowered, and workability is inferior. If the blending amount exceeds 4.0 parts by mass, material separation and significant setting delay occur, and the mechanical properties of the cured product may be deteriorated.
The water reducing agent can be used in a liquid or powder form.

  The amount of water when preparing the blend is preferably 10 to 30 parts by mass, more preferably 12 to 28 parts by mass, with respect to 100 parts by mass of cement. If the amount of water is less than 10 parts by mass, kneading becomes difficult, the fluidity of the blend is extremely lowered, and workability is inferior. If the amount of water exceeds 30 parts by mass, the mechanical properties after curing deteriorates.

In the blend of the present invention, inorganic particles having a Blaine specific surface area of 2,500 to 30,000 cm ² / g and a larger Blaine specific surface area than the cement can be blended. By blending the inorganic particles, the fluidity of the blend can be improved, and the strength and the like of the cured product can be increased.
Examples of the inorganic particles include slag, limestone powder, feldspar, mullite, alumina powder, quartz powder, fly ash, volcanic ash, silica sol, carbide powder, and nitride powder. Among these, slag, limestone powder, and quartz powder are preferably used in terms of cost and quality stability after curing.
Inorganic particles, Blaine specific surface area of 2,500~30,000cm ² / g, preferably 4,500~20,000cm ² /
g and has a larger Blaine specific surface area than the cement particles.
If the Blaine specific surface area of the inorganic particles is less than 2,500 cm ² / g, the difference in Blaine specific surface area with the cement becomes small, and it is difficult to ensure high fluidity, and 30,000
If it exceeds cm ² / g, there are disadvantages such as it becomes difficult to obtain materials because it takes time to grind, and it becomes difficult to obtain a predetermined fluidity.

When the inorganic particles have a Blaine specific surface area larger than that of the cement, the inorganic particles have a particle size that fills the gap between the cement and the fine particles, and high fluidity and the like can be ensured.
Difference Blaine specific surface area of the inorganic particles and the cement, from the viewpoint of the strength developing property after curing and workability before curing, preferably at least ^{1,000cm 2 / g, 2,000cm 2 /} g or more is more preferable.
The compounding quantity of an inorganic particle is 55 mass parts or less with respect to 100 mass parts of cement, Preferably it is 5-50 mass parts. When the blending amount exceeds 55 parts by mass, the fluidity of the blend is lowered and the workability tends to be inferior.

In the present invention, two different kinds of inorganic particles A and inorganic particles B can be used in combination as the inorganic particles.
In this case, the inorganic particles A and the inorganic particles B may use the same type of powder (for example, limestone powder) or different types of powder (for example, limestone powder and quartz powder).
The inorganic particles A have a brain specific surface area of 5,000 to 30,000 cm ² / g, preferably 6,000 to 20,000 cm ²
/ g. The inorganic particles A have a larger Blaine specific surface area than the cement and the inorganic particles B.
If the Blaine specific surface area of the inorganic particles A is less than 5,000 cm ² / g, the difference in Blaine specific surface area between the cement and the inorganic particles B will be small, and workability will be better than when using the above-mentioned one kind of inorganic particles. This is not preferable because not only the effect of improving the properties and the like is reduced, but also the use of two types of inorganic particles, which takes time to prepare the material. If the Blaine specific surface area exceeds 30,000 cm ² / g, it takes time to grind, so that there are disadvantages such as difficulty in obtaining the material and difficulty in obtaining a predetermined fluidity.

In addition, since the inorganic particles A have a larger Blaine specific surface area than the cement and the inorganic particles B, the inorganic particles A have a particle size that fills the gaps between the cement and the inorganic particles B and the fine particles. Excellent fluidity can be ensured.
Difference in Blaine specific surface area between inorganic particle A and cement and inorganic particle B (in other words, difference in Blaine specific surface area between inorganic particle A and cement and inorganic particle B having the larger Blaine specific surface area) is hardened. From the viewpoint of previous workability and strength development after curing, 1,000 cm ² / g or more is preferable, and 2,000 cm ² / g or more is more preferable.

The Blaine specific surface area of the inorganic particles B is 2,500 to 5,000 cm ² / g. The difference between the Blaine specific surface area of the cement and the inorganic particles B is, 100 cm is preferably at least ² / g, from the viewpoint of the strength developing property after curing and workability before curing, 200 cm ² / g or more is more preferable.
If the Blaine specific surface area of the inorganic particles B is less than 2,500 cm ² / g, there are disadvantages such as reduced fluidity, and if it exceeds 5,000 cm ² / g, the numerical value of the Blaine specific surface area approaches that of the inorganic particles A. As compared with the case where one kind of inorganic particles is used, the effect of improving workability and the like is reduced, and since two kinds of inorganic particles are used, it takes time to prepare materials. Absent.
Further, when the difference in the specific surface area of the brane between the cement and the inorganic particles B is 100 cm ² / g or more, the filling property of the particles constituting the compound can be improved, and more excellent fluidity and the like can be secured. .

The compounding amount of the inorganic particles A is 10 to 50 parts by mass, preferably 15 to 40 parts by mass with respect to 100 parts by mass of cement. The compounding amount of the inorganic particles B is 5 to 35 parts by mass, preferably 10 to 30 parts by mass with respect to 100 parts by mass of cement. When the blending amount of the inorganic particles A and the inorganic particles B is out of the above numerical range, the effect of improving workability and the like is reduced as compared with the case of using the one kind of inorganic particles, and two kinds of inorganic particles are used. This is not preferable because it takes time to prepare the material.
The total amount of inorganic particles A and inorganic particles B is preferably 15 to 50 parts by mass with respect to 100 parts by mass of cement.

In the blend of the present invention, one or more fibers selected from the group consisting of metal fibers, organic fibers and carbon fibers can be blended.
The metal fiber is blended from the viewpoint of greatly increasing the bending strength and the like of the cured body.
Examples of metal fibers include steel fibers, stainless fibers, and amorphous fibers. Among these, steel fibers are excellent in strength and are preferable from the viewpoint of cost and availability. The size of the metal fiber is preferably 0.01 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of the metal fiber in the composition and improving the bending strength of the cured body. Is more preferably 0.05 to 0.5 mm and the length is 5 to 25 mm. The aspect ratio (fiber length / fiber diameter) of the metal fiber is preferably 20 to 200, more preferably 40 to 150.

The shape of the metal fiber is preferably a shape that imparts some physical adhesion (for example, a spiral shape or a waveform) rather than a straight shape. If it is in a spiral shape or the like, the stress is secured while the metal fibers and the matrix are pulled out, so that the bending strength is improved.
Preferable examples of metal fibers include, for example, an interfacial adhesion strength (adhesion) to a matrix of a hydraulic hardened body made of steel fibers having a diameter of 0.5 mm or less and a tensile strength of 1 to 3.5 GPa and having a compressive strength of 180 MPa. The maximum tensile force per unit area of the surface is 3 MPa or more.
In the present invention, the metal fiber can be processed into a corrugated or helical shape. Moreover, the groove | channel or protrusion for resisting the motion (longitudinal slip) with respect to a matrix can also be attached on the surrounding surface of the metal fiber of this invention. In addition, the metal fiber of the present invention has a metal layer having a Young's modulus smaller than that of the steel fiber on the surface of the steel fiber (for example, one consisting of one or more selected from zinc, tin, copper, aluminum, etc.). It is good also as what provided.

  The blending amount of the metal fiber is preferably 4% or less, more preferably 0.5 to 3%, and particularly preferably 1 to 3% in terms of volume percentage in the blend. If the blending amount exceeds 4%, the unit water amount increases in order to ensure workability at the time of kneading, and even if the blending amount is increased, the reinforcing effect of the metal fiber is not improved. This is not preferable because a so-called fiber ball is likely to be formed in the kneaded product.

The organic fiber and the carbon fiber are blended from the viewpoint of increasing the breaking energy of the cured body.
Examples of the organic fiber include vinylon fiber, polypropylene fiber, polyethylene fiber, and aramid fiber. Among these, vinylon fibers and / or polypropylene fibers are preferably used in terms of cost and availability.
Examples of the carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber.
The dimensions of the organic fiber and carbon fiber should be 0.005 to 1.0 mm in diameter and 2 to 30 mm in length from the viewpoint of preventing material separation of these fibers in the formulation and improving fracture energy after curing. Preferably, the diameter is 0.01 to 0.5 mm and the length is 5 to 25 mm. The aspect ratio (fiber length / fiber diameter) of the organic fiber and carbon fiber is preferably 20 to 200, more preferably 30 to 150.

  The blending amount of the organic fiber and the carbon fiber is preferably 10.0% or less, more preferably 1.0 to 9.0%, and particularly preferably 2.0 to 8.0% in terms of volume percentage in the blend. If the blending amount exceeds 10.0%, the unit water amount increases to ensure workability during kneading, and the fiber strengthening effect does not improve even if the blending amount is increased. This is not preferable because so-called fiber balls are easily generated in the object.

Fibrous particles or flaky particles having an average particle size of 1 mm or less can be blended with the blend of the present invention. Here, the particle size of the particle is the size of the maximum dimension (particularly, the length of the fibrous particle). By blending fibrous particles or flaky particles, the toughness of the cured product can be increased.
Examples of fibrous particles include wollastonite, bauxite, mullite, and examples of flaky particles include mica flakes, talc flakes, vermiculite flakes, and alumina flakes.
The compounding amount of the fibrous particles or flaky particles is preferably 35 parts by mass or less, more preferably 1 to 25 parts by mass with respect to 100 parts by mass of cement. When the blending amount exceeds 35 parts by mass, the fluidity of the blend is lowered and the workability tends to be inferior.
As the fibrous particles, it is preferable to use particles having a needle degree expressed by a length / diameter ratio of 3 or more from the viewpoint of increasing the toughness of the cured product.

Next, the physical properties (flow value, compressive strength, bending strength, fracture energy) of the blend and its cured product will be described.
The flow value of the formulation is preferably 230 mm or more, more preferably 240 mm or more.
When inorganic particles A and inorganic particles B are used as the inorganic particles, the flow value of the blend is preferably 240 mm or more, more preferably 250 mm or more. In particular, when a fine aggregate having a particle content of 75 μm or less is 2.0% by mass or less, the flow value is preferably 250 mm or more, more preferably 260 mm or more, and particularly preferably 270 mm or more. In this specification, the flow value is `` JIS
In the method described in “R 5201 (Cement physical test method) 11. Flow test”, the value measured without performing the falling motion 15 times (also referred to as “0 stroke flow value” in this specification). is there.
In the flow test, the time for the flow value to reach 200 mm is preferably within 10.5 seconds, and more preferably within 10.0 seconds. The time is used as a scale for evaluating workability and viscosity.

The compressive strength of the cured product of the blend is preferably 100 N / mm ² or more, more preferably 110 N / mm ² or more, and particularly preferably 120 N / mm ² or more. When the compressive strength is less than 100 N / mm ² , it becomes difficult to use a deformed steel bar having a small length / diameter ratio (for example, less than 40) as a structural reinforcing bar.
Flexural strength of the cured product is preferably 15N / mm ² or more, more preferably 18N / mm ² or more, and particularly preferably 20 N / mm ² or more. In particular, when the blend contains metal fibers, the bending strength of the cured body is preferably 30 N / mm ² or more, more preferably 32 N / mm ² or more, and particularly preferably 35 N / mm ² or more.
Fracture energy of the cured product, for example, metal fibers, when blended with any one or more organic fibers and carbon fibers, preferably 10 kJ / m ² or more, more preferably 20 kJ / m ² or more.

The kneading method of the composition of the present invention is not particularly limited. For example, (a) materials other than water and water reducing agents (specifically, cement, fine particles, fine aggregate (and inorganic particles)) are used. A premix material is prepared by mixing in advance, and the premix material, water and a water reducing agent are put into a mixer and kneaded. (B) A powdery water reducing agent is prepared, and materials other than water are prepared. A premix material is prepared by mixing in advance, and the premix material and water are put into a mixer and kneaded. (C) Each material is individually put into a mixer and kneaded. can do.
The mixer used for kneading may be of any type used for ordinary concrete kneading. For example, a rocking mixer, a pan type mixer, a biaxial kneading mixer, or the like is used.

In the present invention, the ratio of length / diameter is 5 or more, preferably in the cured product of the above composition,
6 or more, more preferably 7 or more deformed bars are arranged, and the deformed bars are used as structural reinforcing bars. When the ratio is less than 5, the adhesive force between the deformed bar steel and the hydraulic hardened body is small, and it becomes difficult to obtain the reinforcing effect of the hydraulic hardened body by the deformed bar steel.
In the present invention, a deformed steel bar having a length / diameter ratio of 5 to 20 and a deformed steel bar having a length / diameter ratio exceeding 20 may be combined.

The adjustment ring of the present invention can be produced by a method such as holding a reinforcing bar at a predetermined position in the mold, and curing the composition after being placed in the mold. As described above, the formulation used in the present invention has excellent flowability with a zero stroke flow value of 230 mm or more, and therefore the adjustment ring can be easily manufactured (particularly molded).
In addition, the curing method is not particularly limited, and air curing, steam curing, or the like may be performed.

Next, a reference example of a reinforcing steel reinforced hydraulic cured body produced by using the composition defined in the present invention will be described based on the drawings.
In FIG. 1, a reinforcing steel reinforced hydraulic hardened body 1 is a thin and elongated member (for example, a louver) , and the reinforcing bars arranged inside are indicated by dotted lines. Moreover, in FIG. 1, (a) is a front view, (b) is a bottom view, and (c) is a partially enlarged view of (b).
Reinforcing bar reinforced hydraulic hardened body 1 is composed of four short steel bars 2 (diameter: 9.53 mm, length / diameter ratio: 16.8) and two long steel bars 3 (for example, Round steel; diameter: 10 mm, length / diameter ratio exceeding 100) is manufactured by welding. This reinforcing bar structure is embedded in a hydraulic hardened body 4 made of a specific composition defined in the present invention.
In addition, the dimension of the reinforcing steel reinforced hydraulic cured body 1 is 150 cm (length) × 20 cm (width) × 4 cm (thickness).
The reinforcing steel reinforced hydraulic cured body 1 has a higher mechanical strength than a case where a hydraulic cured body made of a composition other than the composition defined in the present invention is used instead of the hydraulic cured body 4.

Next, an example of the adjustment ring of the present invention will be described based on the drawings.
FIG. 2 is a plan view of the substantially circular adjustment ring of the present invention , and the reinforcing bars arranged inside are indicated by dotted lines.
The adjustment ring (reinforcing bar reinforced hydraulic cured body) 20 has a substantially circular ring-shaped hydraulic cured body made of a specific composition defined in the present invention as a main body 21, and is concentric with the main body 21 in the main body 21. From two ring-shaped long rebars 22a and 22b, which are a substantially circular closed rod-shaped body, and eight short reinforcing bars 23 for reinforcing a hydraulic hardened body (main body 21) made of the above-mentioned specific composition. Reinforced bar structure is arranged. In this reinforcing bar structure, one of the two ring-shaped long reinforcing bars is disposed on the inner peripheral side of the main body 21 and the other is disposed on the outer peripheral side of the main body 21, and the ring-shaped long reinforcing bars 22 a and 22 b are arranged. At short intervals in the circumferential direction, short reinforcing bars 23 made of eight deformed steel bars are arranged so as to intersect the ring-shaped long reinforcing bars 22a and 22b substantially perpendicularly.
The adjustment ring is not limited to a substantially circular ring shape. For example, a substantially rectangular ring shape or a polygonal ring of approximately pentagonal shape or more is used so as to match the shape of the manhole cover or the vertical hole of the manhole. It may be in a shape.

  As the ring-shaped long reinforcing bar arranged in the adjustment ring, either round steel (a steel bar having a smooth peripheral surface) or a deformed steel bar can be used.

The short reinforcing bar for reinforcing the ring-shaped main body (hydraulic hardened body) is made of a specific deformed steel bar defined in the present invention. The dimension of this deformed steel bar varies depending on the size of the main body (hydraulic hardened body) of the adjusting ring in which the short reinforcing bar is embedded, but the appropriate distance between each of the outer peripheral edge and inner peripheral edge of the adjusting ring and the short reinforcing bar. In consideration of securing (so-called securing of the cover thickness), the nominal name is preferably D6 to D19, more preferably D6 to D16, particularly preferably D6 to D13, and the length / diameter ratio is 5 to 20 , preferably Is 6-18, more preferably 7-16.

The short rebar for reinforcing the ring-shaped main body (hydraulic hardened body) is formed on the ring-shaped long rebar so that it intersects the ring-shaped long rebar approximately perpendicularly to improve the reinforcing effect. It is preferably fixed by welding or the like.
A particularly preferable number of short reinforcing bars arranged in the adjusting ring is 3 to 10.
In addition, short reinforcing bars for reinforcing the ring-shaped main body (hydraulic hardened body) are provided at substantially equal intervals in the ring-shaped main body in order to improve the reinforcing effect evenly against loads applied from above. It is preferable that the ring-shaped long reinforcing bar is fixed to the long reinforcing bar at equal intervals in the circumferential direction.

Next, a method for using the adjusting ring of the present invention will be described.
FIG. 3 is a cross-sectional view showing an example of a manhole neck structure using the adjustment ring 20 shown in FIG. 2 (in FIG. 3, reinforcing bars arranged in the adjustment ring 20 are not shown). As shown in FIG. 3, the neck of the manhole is stacked on the upper floor slab 31 a of the manhole block 31 constituting the wall surface of the vertical hole 30 formed in the ground, and the adjustment ring 20 is stacked on the upper end surface of the adjustment ring 20. Further, a neck adjustment member 33 made of mortar for height adjustment is further stacked, a lid receiving frame 34 is placed on the neck adjustment member 33, and an upper surface identical to the ground surface A is formed on the lid receiving frame 34. The manhole cover 32 is placed. The lid receiving frame 34 is fixed to the adjustment ring 20 by receiving frame fixing bolts 35 inserted through the flange portion 34 a of the lid receiving frame 34 and the neck adjustment member 33.
When a passing vehicle or the like passes over the manhole cover 32 and a large load is applied, a large pressure is applied to the contact surface between the lowermost adjustment ring 20 and the upper floor slab 31a.
Since the mechanical strength and durability of the adjustment ring 20 are improved by using the adjustment ring 20 of the present invention , even if a passing vehicle or the like passes over the manhole cover 32 and a large load is repeatedly applied. In addition, cracks and the like hardly occur and can be used for a long time.

Hereinafter, the present invention will be described by way of examples.
[Example 1]
1. Materials used The following materials were used.
(1) Cement; Low heat Portland cement (manufactured by Taiheiyo Cement; Blaine specific surface area: 3,200 cm ² / g)
(2) Fine powder; silica fume (BET specific surface area: 10 m ² / g)
(3) Inorganic particles: quartz powder (Blaine specific surface area: 7,500 cm ² / g)
(4) Aggregate; quartz sand (maximum particle size: 0.6 mm, content of particles of 75 μm or less: 0.3 mass%)
(5) Metal fiber: Steel fiber (diameter: 0.2mm, length: 13mm)
(6) Fibrous particles: wollastonite (average length: 0.3 mm, length / diameter ratio: 4)
(7) Water reducing agent; Polycarboxylic acid-based high-performance water reducing agent (8) Water; Tap water

2. Properties of the blend and its cured product 100 parts by mass of low heat Portland cement, 32 parts by mass of silica fume, 120 parts by mass of silica sand, 30 parts by mass of quartz powder, 5 parts by mass of wollastonite, 1.0 part by mass of water reducing agent (solid content with respect to cement), 22 parts by mass of water and steel fibers (volume ratio in the blend: 2%) were put into a biaxial kneader and kneaded.
The flow value of the blend was measured in the method described in “JIS R 5201 (cement physical test method) 11. Flow test” without performing 15 drop motions. As a result, the flow value was 260 mm.
Further, the blend was poured into a mold of φ50 × 100 mm, preliminarily placed at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours to obtain hydraulic hardened bodies (three pieces). The cured body had a compressive strength (average of 3) of 230 N / mm ² .
Furthermore, the blend was poured into a 4 × 4 × 16 cm mold, pre-positioned at 20 ° C. for 48 hours, and then steam-cured at 90 ° C. for 48 hours to obtain hydraulic hardened bodies (three). The bending strength (average value of 3 pieces) of the cured product was 47 N / mm ² .

3. Confirmation test of reinforcement effect of deformed bar with length / diameter ratio of 10 (1) Preparation of test specimen Deformed bar with diameter of 9.53 mm x length of 100 mm (length / diameter ratio: 10.5) is held in place Into a mold having a width of 100 mm, a thickness of 70 mm, and a length of 400 mm, the same composition as the composition of “2. Properties of the composition and its cured product” is poured, and after pre-treatment at 20 ° C. for 24 hours, 90% Steam curing was performed at ℃ 48 hours to obtain a rebar-reinforced hydraulic hardened body. A cutout portion having a depth of 20 mm was formed at the center in the longitudinal direction of the cured body from the lower surface upward, and a test body 10 (Example) shown in FIG. 4 was produced.
4A is a left side view of the test body 10, and FIG. 4B is a front view of the test body 10. 4 (a), the cover thickness D1 from the front surface 10a or the back surface 10b of the deformed steel bar 11 is 45 mm. In FIG. 4 (b), the cover thickness D2 from the top surface of the deformed steel bar 11 is 33 mm. The cover thickness D3 from the lower surface was 27 mm, and the cover thickness D4 from the left and right side surfaces was 150 mm. In addition, the code | symbol 12 in a figure shows a hydraulic hardening body, and the code | symbol 13 shows a notch part.
In addition to the above-described test body 10, a comparative test body (Comparative Example 1) was manufactured in the same manner as the above-described test body except that the deformed steel bar was not arranged.
(2) Reinforcing effect confirmation test The following test was performed on the above-described specimens (Example 1, Comparative Example 1).
(A) Test of relationship between load and loading point displacement Notched three-point bending test according to “JCI-S-002-2003 (Load-displacement curve test method of fiber reinforced concrete using notched beam)” The change of the loading point displacement according to the increase in the load in the test body (Example 1, Comparative Example 1) was measured. The results are shown in FIG.
(B) Test of relationship between load and rebar strain In the notched three-point bending test of (a), the change in rebar strain corresponding to the increase in load in the specimen (Example 1) Measured with a strain gauge. The results are shown in FIG.

(C) Consideration of test results As shown in FIG. 5, the specimen with the deformed bar (Example 1) has a maximum load 1.5 times that of the specimen without the deformed bar (Comparative Example). As described above, it was found that even when a short deformed steel bar having a length / diameter ratio of 10.5, which cannot be expected from the conventional technology, is used, a large reinforcing effect can be obtained.
Further, as shown in FIG. 6, it was found that the specimen (Example 1) in which deformed bar steel bars were arranged had increased rebar strain up to a maximum load of 30 kN and had excellent load resistance. Further, after the maximum load was applied, the reinforcing bar strain was alleviated without changing the load value, and then the load was reduced and finally fractured. As described above, even after the maximum load was applied, the specimen was kept without breaking immediately, so that the excellent effect of the short deformed steel bar was confirmed.

Next, an example of the adjustment ring of the present invention will be described.
[Example 2]
As shown in FIG. 2, using “1. materials used” in Example 1, the compound of “2. Properties of compound and its cured product” in Example 1 was replaced with two ring-shaped long reinforcing bars. (Special steel bar, nominal name: D13) and 8 short reinforcing bars (special steel bar, diameter: 9.53 mm, length / diameter ratio: 10.5) to reinforce the hardened body of the above compound Pour into a ring-shaped mold holding the rebar structure in place, after 24 hours in advance at 20 ° C., steam curing at 90 ° C. for 48 hours, in the main body 21 made of a cured product of the above composition, An adjustment ring 20 for testing in which the above-described reinforcing bar structure was embedded was obtained.
The above-mentioned reinforcing bar structure is configured so that each of the eight short reinforcing bars 23 is spaced from the two ring-shaped long reinforcing bars 22a and 22b at equal intervals in the circumferential direction of the two ring-shaped long reinforcing bars 22a and 22b. Thus, they are fixed by welding so as to intersect substantially vertically.

[Comparative Example 2]
As shown in FIG. 7, in the same manner as in Example 2 except that the short reinforcing bars made of deformed steel bars are not fixed to the two ring-shaped long reinforcing bars 42 a and 42 b, “2. And the adjustment ring 40 for a test which embed | buried two ring-shaped long reinforcing bars 42a and 42b in the main body 41 which consists of a hardening body of the composition of "the property of the hardening body" was obtained.

[Comparative Example 3]
The blends and materials shown in Table 1 were charged into a biaxial kneader and kneaded to obtain blends. As shown in FIG. 2, in the same manner as in Example 2, the above-mentioned blend was placed in a main body 21 made of a cured product of the above-mentioned blend, with two ring-shaped long reinforcing bars 22 a and 22 b and eight short reinforcing bars. An adjustment ring 20 for testing in which a reinforcing bar structure consisting of 23 was embedded was obtained.
For the above compound, slump was measured according to “JIS A 1101”, and “JIS”
The compressive strength was measured according to `` A 1108 '' and the bending strength was measured according to `` JIS A 1106 ''. The slump was 8 cm, the compressive strength was 30 N / mm ² and the bending strength was 3.9 N / mm. ² .

[Comparative Example 4]
As shown in FIG. 7, the composition shown in Table 1 and the composition of the materials are the same as in Comparative Example 3 except that the short reinforcing bars made of deformed steel bars are not fixed to the two ring-shaped long reinforcing bars 42a and 42b. A test adjustment ring 40 was obtained in which two ring-shaped long reinforcing bars 42a and 42b were embedded in a main body 41 made of a cured product.

[Static load strength loading test of adjustment ring]
About the adjustment ring 20 or the adjustment ring 40 (Example 2 and Comparative Examples 2 to 4) for the test described above, using the Amsler type 200-ton universal testing machine shown in FIG. A test was conducted.
(1) Static load strength loading test method for adjustment ring As shown in FIG. 8, on a pedestal 50 assuming an upper floor slab of a manhole block, strain gauges (not shown) are provided at a plurality of positions on the upper surface. The adjustment ring 20 was placed. A loading plate 51 was placed on the adjustment ring 20. The pedestal 50, the adjustment ring 20, and the loading plate 51 are installed in an Amsler type 200-ton universal testing machine 52, and the 200-ton Amsler head 52a of the testing machine 52 is used at a loading speed of 100 kgf / second (980 N / second). A load of 195 tons was applied to the adjustment ring 20 from the loading plate 52, and the generated stress applied to the adjustment ring 20 was measured by a strain gauge as a change in strain corresponding to the increase in load. The results are shown in FIG.

(2) Consideration of test results As shown in FIG. 9, the adjustment ring of Example 2 was not broken even after the maximum load (195 tons) was applied, and the strain continued to increase. It was found to have loadability. In contrast, the adjustment ring of Comparative Example 2 was broken with a load of about 1,500 kN, and the adjustment rings of Comparative Examples 3 and 4 were both broken with a load of about 500 kN.
That is, in the adjustment rings of Comparative Examples 3 and 4, the reinforcing bar structure including only the ring-shaped long reinforcing bars is embedded in the cured body, and the reinforcing bar structure including the ring-shaped long reinforcing bars and the short reinforcing bars is included in the cured body. In the case where it was buried in the load, the load resistance did not change, whereas the adjustment ring of Example 2 improved the load resistance by 1.2 times or more compared with the adjustment ring of Comparative Example 2.
From this result, the adjusting ring of the present invention has an excellent mechanical strength that cannot be expected from an adjusting ring in which a reinforcing bar structure using a deformed steel bar is embedded in a normal hydraulic hardened body as in Comparative Example 3. And it was confirmed that it had durability. In addition, compared with the adjustment ring of Comparative Examples 3 and 4, the load resistance of the adjustment ring of Example 2 was improved by 4.0 times or more.

(A) is a front view which shows an example of a reinforcing steel reinforced hydraulic hardening body, (b) is the bottom view, (c) is the elements on larger scale of (b). It is a top view of an example of the adjustment ring of this invention . It is sectional drawing which shows an example of the neck part structure of the manhole which uses the adjustment ring of this invention. (A) is the left view of the test body of a reinforcing steel reinforced hydraulic hardening body, (b) is the front view. It is a figure which shows the relationship between a load and a loading point displacement. It is a figure which shows the relationship between a load and a reinforcement distortion. It is a top view which shows the adjustment ring of a comparative example. It is a figure explaining the static load strength loading test method using an Amsler type 200-ton universal testing machine. It is a figure which shows the relationship between a load and a distortion | strain. It is sectional drawing which shows an example of the neck part structure of the manhole which uses the conventional adjustment ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement reinforced hydraulic hardening body 2 Deformed bar steel 3 Round steel 4 Hydraulic hardening body 10 Test body 10a Front surface of the test body 10b Back surface of the test body 11 Deformed bar steel 12 Hydraulic hardening body 13 Notch 20 Adjustment ring (rebar reinforcement hydraulic Cured body)
21 body (hydraulic cured body)
22a, 22b Ring-shaped long rebar 23 Short rebar (deformed bar)
30 Vertical hole 31 Manhole block 31a Upper floor plate 32 Manhole cover 33 Neck adjustment material 34 Lid receiving frame 34a Flange 35 Receiving frame fixing bolt 40 Adjustment ring 41 Main body (hydraulic hardened body)
42a, 42b Ring-shaped long rebar 50 Pedestal 51 Loading plate 52 Amsler 200 ton universal testing machine 52a 200 ton Amsler head 60 Adjustment ring 61 Vertical hole 62 Manhole block 62a Upper floor plate 63 Neck adjustment material 64 Lid receiving frame 64a Flange part 65 Manhole Lid 66 Bolt for fixing receiving frame A Ground surface

Claims (6)

An adjustment ring for supporting the manhole cover,
And cement 100 parts by weight of (A) Blaine specific surface area 2,500~5,000cm ² / g, (B) silica fume, silica dust, consisting of fly ash, slag, volcanic ash, silica sol, or precipitated silica, BET specific surface area 5~25m ² / In the ring-shaped hydraulic cured body comprising a composition containing 10 to 40 parts by mass of g fine particles, (C) fine aggregate, (D) water reducing agent, and (E) water, the hydraulic curing One or more ring-shaped long reinforcing bars that are concentric with the body, and are arranged so as to intersect the ring-shaped long reinforcing bars substantially perpendicularly at equal intervals in the circumferential direction of the ring-shaped long reinforcing bars An adjusting ring comprising a short reinforcing bar made of deformed steel bar having a length / diameter ratio of 5 to 20 . The formulation, (F) with Blaine specific surface area 2,500~30,000cm ^{2 /} g, and adjustment ring according to claim 1 further comprising inorganic particles having a large Blaine specific surface area than the cement. The inorganic particles (F) is, the adjustment ring according to claim 2, wherein composed of the inorganic particles A of Blaine specific surface area 5,000~30,000cm ² / g, the Blaine specific surface area 2,500~5,000cm ² / g and inorganic particles B. The adjustment ring according to any one of claims 1 to 3 , wherein the blend includes one or more fibers selected from the group consisting of (G) metal fibers, organic fibers, and carbon fibers. The adjustment ring according to any one of claims 1 to 4 , wherein the blend comprises (H) fibrous particles or flaky particles having an average particle size of 1 mm or less. The adjusting ring according to any one of claims 1 to 5 , wherein the compressive strength of the hydraulic cured body is 100 N / mm ² or more.

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