JP2000128611A - Light-weight cement mortar for bolt box hole filling method of construction and bolt box hole filling method of construction using light-weight cement mortar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily pour and fill a light-weight cement mortar into a bolt box without leaving gaps so as to make a composition in pouring have a specific gravity and a flow value in pouring in specific regions and develop a strength equal to or higher than that of a concrete building segment in setting. SOLUTION: This mortar has a composition in pouring having 0.5-1.9 specific gravity and 140-210 mm flow value and can be completely filled into a bolt box by force feed by a pump under 0.5-3.0 kgf/cm2 positive pressure. The mortar preferably comprises 20-85 wt.% of cement, 0.1-5 wt.% of lightweight aggregate, 5-80 wt.% of an inorganic admixture and 0.2-5 wt.% of an organic admixture. An organic aggregate such as EVA-calcium carbonate expanded aggregate, etc., or an inorganic aggregate such as perlite, etc., can be used as the lightweight aggregate. Silica sand, shrinkage reducing agent, etc., can be used as the inorganic admixture. An acrylic fiber, etc., can be used as the organic admixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an underground conduit, a subway passage, a sewage conduit, a collective conduit for electric wires and gas pipes, and the like, which has an opening at a periphery of a concrete segment used as a material. For lightweight cement mortar to be injected and filled into the connected bolt box, especially for high-rise bolt boxes near the ceiling, etc. The present invention relates to a lightweight cement mortar for a bolt box filling method having the same strength as that of a bolt box filling method, and a bolt box filling method using a lightweight cement mortar.

[0002]

2. Description of the Related Art When constructing subway passages, sewage pipelines, collecting pipelines such as electric wires and gas pipes, etc., which are buried underground, vertical holes are excavated and formed to a predetermined depth to form predetermined horizontal holes. The apparatus is carried in, and while the apparatus is operated to form a horizontal hole, segments are sequentially connected to construct a pipeline having a predetermined diameter. This segment is made of precast concrete, iron, etc., and is generally made of precast concrete or iron. Are formed, the segments are arranged so that the bolt boxes are adjacent to each other, and they are joined by bolt nuts. If the bolt box is left exposed, the bolt and nut will corrode. Filling the bolt box with cement mortar, epoxy resin, polyurethane resin, etc. prevents corrosion of the bolt and nut, and as a result, prevents reduction in joint strength. The hole filling method had been used.

[0003] The mortar filling method may be applied to an air mortar method in which a mortar is blown together with air, a quick setting mortar method in which a quick setting mortar containing a quick setting agent is reduced, and a light weight mortar in which a specific gravity is reduced. A mortar method, a hard urethane method for injecting and filling a two-pack curing / foaming type urethane composition, and the like are known.

[0004]

However, each of the conventional methods has problems in construction and quality as described below.

In the air mortar method, since the mortar is blown together with the air, the mortar is difficult to construct and has little practical use. (Problems in construction) Generation of dust is enormous. High fluidity. Long curing time. The installation amount at one location is small.

[0006] The quick-setting mortar method is a method in which the quick-setting mortar is divided into several parts and hand-finished to finish the surface with iron.
Although the material cost is low, the construction efficiency is poor, labor costs are high, and transportation costs in the mine are high, so that the economic efficiency is poor, and the quality and workability are inferior to other construction methods. (Problems in construction) Due to its high specific gravity, a formwork to prevent falling off is required near the ceiling in the mine. The amount of kneading per operation is small due to the use of a quick setting agent. (Problems in quality) Filling into the recess near the ceiling or around the bolt in the mine is uncertain. Due to hand filling, voids are easily formed. Boxes near the ceiling may fall off after curing. There is a risk of cracking and falling off due to drying shrinkage.

[0007] The lightweight mortar method is a method in which the lightweight mortar is divided into several parts and hand-finished to finish the surface with a different material, and often contains a quick-setting agent. This method is
Although material costs are relatively low, construction efficiency is poor, labor costs are high, transportation costs inside the mine are high, and surface finishing costs are required, which is inferior in economic efficiency, but there is room for improvement. (Problems in construction) Although the specific gravity is small, it is necessary to take measures to prevent falling off near the ceiling in the mine. The amount of kneading per operation is small due to the use of a quick setting agent. (Problems in quality) Filling into the recess near the ceiling or around the bolt in the mine is uncertain. Due to hand filling, voids are easily formed. There is a risk of cracking and falling off due to drying shrinkage.

[0008] The hard urethane foam method is a method in which urethane is injected and foamed through an injection hole by filling a mold, and the surface is finished with mortar. A method of leaving the mold as it is has also been proposed. This method is advantageous in terms of workability (fillability) compared to other methods, has the advantage of lower labor costs, and has lower transportation costs in the mine, but is an organic material and a foam. Therefore, the strength is clearly weaker than an inorganic hardened body (hardened mortar) obtained by another method. (Problems in construction) It is difficult to control the injection amount. Two-component reaction management is required. (Problems in quality) The strength of urethane alone is low. If an unexpected amount of heat acts, there is a possibility that a problem may occur in terms of heat resistance.

On the other hand, Japanese Patent Publication No. Hei 7-88755 discloses that
A method of filling a hole in which the connection box is closed with a reinforcing thin plate and then injecting a filler into the box and curing the same is proposed. Examples of the filler include various resin liquids such as cement mortar, epoxy resin, and polyurethane resin. ing. However, the composition of these fillers is not disclosed at all, and it is described as “expanded and cured over time” later in the examples of the fillers. It merely suggests a rigid urethane foam method. That is, when filling the cement mortar, instead of filling by hand as in the past,
It merely describes the idea of improving workability by filling by injection, does not describe many problems associated with implementation, and of course, a composition that solves them has not yet been found. Not.

[0010]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above, and is a lightweight cement mortar for filling a closed space formed by fixing a lid material so as to close a bolt box. Having a specific gravity of 0.5 to 1.
9. The present invention relates to a lightweight cement mortar for a bolt box filling method, which has a flow value of 140 to 210 mm and has the same strength as a concrete segment or more when hardened.

The present invention also proposes a method for filling a hole in a bolt box using the lightweight cement mortar, wherein a lid member is fixed so as to close the bolt box.
Attach an injection plug (the tip of the injection hose) of lightweight cement mortar to the injection port formed in the lid material, and attach an exhaust plug (the base end of the exhaust hose) that discharges internal air to the exhaust port formed in the lid material. The lightweight cement mortar is pumped by a pump, completely filled with a positive pressure of 0.5 to 3.0 kgf / cm ² from the injection plug into the bolt box, and filled with the lightweight cement mortar in the bolt box. And removing the exhaust plug and closing the inlet and the exhaust port of the lid material.

In the above hole filling method, the cover material was not removed. That is, the lid material is used as a disposal mold. However, the lightweight cement mortar of the present invention can be applied to a method of removing the lid material after the mortar is injected and filled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The development of the present invention will be described below, and the present invention will be described. In view of the above situation, the present inventors can easily inject and fill the desired cement mortar into the bolt box closed with a lid, and are lightweight, having a strength equal to or higher than that of the concrete segment. It was found necessary to have.
It is also important to satisfy the standard value of the hydraulic conductivity without shrinkage.

As described above, the lightweight cement mortar of the present invention has a specific gravity of 0.5 to 1.9 and a flow value of 140 to 210 at the time of pouring in the bolt box filling method.
mm, and a positive pressure of 0.5 to 3.0 kgf /
By pumping over cm ² , the bolt box can be completely filled. If the specific gravity of the composition at the time of injection is smaller than 0.5, the composition components are greatly restricted, and it is difficult to obtain a composition satisfying the required quality described below. When the specific gravity is larger than 1.9, it is particularly difficult to inject into the bolt box near the ceiling and the load on the pump is increased, so that a special pump is required. On the other hand, if the flow value is smaller than 140 mm, the fluidity becomes low, and it is difficult to perform pressure feeding. Also,
If the flow value is larger than 210 mm, there is a risk that material separation and breathing during pumping may occur.

Further, the lightweight cement mortar of the present invention comprises:
When hardened, it produces as much or more strength as the concrete segment in which the bolt box is formed. still,
The concrete segment has various strengths depending on the scale and application of the underground pipeline to be constructed.
What is necessary is just to determine an intensity characteristic according to them. Therefore, in the following description, it is assumed that it has the same strength characteristics as high-strength concrete segments (compression strength 210 kgf / cm ² ) in the construction of subway passages, but it is not particularly limited to this.

As other characteristics, it is desirable to satisfy the following required quality. Water tightness: Permeability coefficient k = 5 × 10 ^-8 cm / sec Corrosion resistance: Alkaline environment in bolt box Prevention of fall-off: No fall-off (confirmed from pull-out and shearing-out tests) Material shrinkage: Allowable drying Less than shrinkage crack width Bolt box between rings 0.19mm Bolt box between segments 0.11mm Influence of residual water pressure: No dropout due to residual water pressure in the segment water pressure (confirmed by water resistance test and pull-out test) Friction resistance: Concrete (compressive strength) Friction resistance equivalent to 210 kgf / cm ² ) Ensuring a roughness coefficient: comparable to concrete (roughness coefficient)
Inner surface finish of 0.015 or less)

In order to satisfy the above-mentioned required quality, the composition was examined by the following policies and test methods.

Watertightness: In order to improve the water resistance of the mortar, a type having high particle size distribution and high waterproofness of the aggregate is selected and a waterproofing agent is used. It may be performed by an input method or the like.

Corrosion resistance: Usually made of Portland cement as a main component, shows strong alkalinity in the environment, and protects iron from rust. This may be confirmed by measuring the pH.

Prevention of falling off: Re-emulsifiable powder resin is used in order to enhance the adhesive performance to the concrete box, and non-shrink mortar and fiber bundle type acrylic fiber or polyolefin fiber, which has a reinforcing effect in the sense of preventing cracks, alkali-resistant glass fiber , Carbon fiber, vinylon fiber, etc. to further increase the breaking strength. The shear bond strength is measured, and it is confirmed that the strength is equal to or more than three times the own weight of the mortar.

Material shrinkage: Shrinkage is suppressed by using aggregates and chemicals (water reducing agents, shrinkage reducing agents) so that the shrinkage does not exceed the allowable dry shrinkage crack width. This test method
JIS A 1129 (mortar and concrete length change test method) and the like.

Influence of residual water pressure: 6 kgf / cm ^2, which corresponds to a water pressure of 60 m underground, is continued for 3 days, and the effect of residual water pressure is examined from the adhesive strength. Determine a composition that makes it difficult for water to penetrate even in a high water pressure environment. Water resistance is determined by the input method, and a pull-out test is performed to confirm that the strength is equal to or more than three times the weight of the mortar.

Friction resistance: Increases compressive strength to concrete strength (compressive strength: 210 kgf / cm ² ). In a fluidized state using a water reducing agent with a well-balanced aggregate particle size distribution and a minimum amount of kneading water, it has good leveling properties and can be densely filled. As this test method, there is a method specified in 9.5 of JIS R 5201.

Further, a water absorption test, a coagulation test, an adhesion strength, a flow value (confirmation), a unit volume mass, a bending strength, a mortar air amount, a mortar breathing test, etc. were performed by tests specified in JIS. The composition may be determined.

In this way, the cement has the above-mentioned specific ranges of the specific gravity and the flow value, and furthermore, the cement 20 to 85
A lightweight cement mortar having a composition containing, by weight, 0.1 to 5% by weight of a lightweight aggregate, 5 to 80% by weight of an inorganic admixture, and 0.2 to 5% by weight of an organic admixture meets the above purpose. I found that.

When a lightweight cement mortar out of the range of each component ratio is used, the required quality cannot be obtained. For example, when the amount of cement is 20 wt% or less, the compressive strength, the water permeability, etc. become low values, and when it is 85 wt% or more, the values such as shrinkage, fluidity, breathing, etc. are poor. When the amount of the lightweight aggregate is 0.1 wt% or less, the specific gravity is heavy and workability deteriorates, and when it is 5 wt% or more, the particle size distribution deteriorates, the workability decreases, and the shrinkage is large. ,
Strength decreases. As this lightweight aggregate, an organic aggregate such as EVA-calcium carbonate expanded aggregate and styrene expanded aggregate, or an inorganic aggregate such as pearlite, glass expanded aggregate and shirasu balloon can be used. Further, when the amount of the inorganic admixture is 5% by weight or less, the compressive strength and shrinkage increase, and the workability decreases. If the content is 80% by weight or more, the strength is reduced, and setting time, poor curing and the like occur. As the inorganic admixture, silica sand, shrinkage reducing agent, dolomite plaster, fly ash, blast furnace slag powder, calcium carbonate and the like can be used. In addition, the amount of the organic admixture is 0.2 w
If it is less than t%, adhesive strength is poor and fluidity is poor.
If the content is 5 wt% or more, curing failure and workability are reduced.
Examples of the organic admixture include fibers such as acrylic fiber, vinylon fiber, and polyolefin-based reinforcing fiber;
Beova, ethylene vinyl acetate, re-emulsifying powder resin such as acrylic resin, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose,
Water-soluble thickeners such as ethylene hydroxyethyl cellulose, high-performance water reducing agents such as naphthalenesulfonic acid condensed salts and sulfonated melamine condensed salts, shrinkage reducing agents such as polyoxyalkylene compounds and alkylene oxide adducts of lower alcohols, aluminum stearate And a waterproofing agent such as a fatty acid metal salt and a dispersing agent. Considering the fluidity at the time of pumping and securing the non-fluid state after the filling is completed, select one or more types of thickeners and fluidizers that exhibit Newtonian flow and those that exhibit non-Newtonian flow. Control the viscosity. The blending of the lightweight cement mortar may be appropriately selected in consideration of fluidity, compressive strength and the like in the above range according to actual required performance. For example, a more desirable formulation example is shown in Table 1.

[0027]

[Table 1]

When the lightweight cement mortar is injected and filled into the bolt box (closed space), it is filled with a positive pressure of 0.5 to 3.0 kgf / cm ² . When filling is performed by applying a positive pressure higher than this range, an excessive amount of lightweight cement mortar will be injected before the filling is confirmed and the operation of the injection pump is stopped. Of course, even if an excessive amount of the lightweight cement mortar is injected, it is discharged from the exhaust port, so there is no problem in the construction, but the amount of the lightweight cement mortar that flows out wastefully increases. Filling can be sufficiently performed even at a positive pressure lower than the above range, but the workability deteriorates.

The lid member for fixing the bolt box so as to close it is provided with an injection port for injecting the lightweight cement mortar and an exhaust port for discharging air in the closed space. The material composition is not particularly limited as long as the material has a strength that does not cause breakage or the like under the pressure applied during the filling and filling of the cement mortar. The diameter of the injection port can be freely determined by the mortar discharge amount and the box capacity. The diameter of the exhaust port is determined by calculation with the inlet and the filling internal pressure. In addition, this lid material is usually fixed using a fixing tool such as an adhesive or a rust-proof bolt, a screw, or the like. Since the weight of the lid acts in addition to the pressure acting during the filling, a lightweight material is desirable. Further, it is more desirable that the material is manufactured using a recycled resource material.
In the description of the lightweight cement mortar, characteristics such as friction resistance were mentioned. However, this lid material is actually located on the surface layer (after injection and filling of the lightweight cement mortar,
Except when the lid is removed), the characteristics required for the friction resistance are also required for this lid.

As a cover material panel having the above-mentioned characteristics, there is, for example, a fly ash reinforced panel. This fly ash reinforced panel is a plastic panel that is made by welding and mixing nylon resin and fly ash, a by-product from a thermal power plant, and then heat-molded.The mechanical properties are high in strength, and the friction properties are also high. Are better. Moreover, it is lightweight and inexpensive. Further, since it is excellent in moldability, it can be formed into a panel having an appropriate size, and it is easy to impart shape characteristics such as a rib structure, a grating structure, and a non-slip structure. Further, when it is necessary to improve the rigidity, strength and heat resistance of the panel, glass fibers may be blended.

In the hole filling method of the present invention, first, the lid having the above-described structure is fixed so as to cover the bolt box, and an injection plug is connected to an injection port provided on the lid, and an exhaust plug is connected to an exhaust port. The injection plug is provided at the tip of an injection hose (tube) extending from a pump for pumping the lightweight cement mortar, and can be used repeatedly, and is a check valve mechanism for preventing backflow of the lightweight cement mortar. Is desirably provided. Next, by operating the pump, a positive pressure of 0.5 to 3.0 kgf / c was introduced into the bolt box from the injection plug by inserting the lightweight cement mortar.
When discharging and filling by applying m ² , air corresponding to the filling amount is discharged from the exhaust plug. And when the lightweight cement mortar fills the bolt box,
Excessive lightweight cement mortar is discharged from the exhaust plug. By confirming the discharge of the excessive lightweight cement mortar, it can be recognized that the bolt box has been filled. Therefore, the length of the exhaust hose (tube) provided with the exhaust plug is not particularly limited, but is preferably made of a transparent material as long as it is long. In addition, since the tip of the exhaust hose is disposed so as to be located at the best point (= generally the uppermost part of the closed space) regardless of the angle of the bolt box, it is flexible. After that, the injection plug and the exhaust plug are removed from the injection port and the exhaust port of the lid material, and the injection port and the exhaust port of the lid material are closed.The lightweight cement mortar may be manually packed and closed. A cap material or the like prepared in advance may be attached to each opening to close the opening.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 4 show conceptual diagrams of a hole filling method according to the present invention. Here, in order to confirm the filling state of the lightweight cement mortar, a case (acryl box) made of a transparent acrylic plate was used instead of the bolt box. FIG. 1 shows an injection plug 2 provided at a distal end of an injection hose 1 and an exhaust plug 4 provided at a base end of an exhaust hose 3. Reference numeral 5 denotes a check valve for preventing backflow of the lightweight cement mortar. Using a rubber or the like that has a shape that can withstand the maximum internal pressure applied to the container and has a low mortar injection resistance.
mm to 5 mm. This time internal pressure limit kgf / cm
² used a valve thickness of 3 mm. 6 is an O-ring, 7 is a mounting screw groove. Figure 2 shows a test case (acrylic box)
8, 9 is a fixing screw, 10 is a cover material, 11
Denotes an inlet, and 12 denotes an outlet.

FIG. 3 assumes a bolt box in the vicinity of the ceiling, in which the cover member 10 is arranged downward. Then, first, the injection plug 2 and the exhaust plug 4 are attached to the acrylic box 8 as shown in FIG. At this time, the base end of the exhaust hose 3 was disposed so as to be located at the uppermost end (back end) in the acrylic box 8. Next, as shown in FIG. 2B, a pump (not shown) connected to the injection hose 1 is operated to start injection and filling of the lightweight cement mortar 13. The injected lightweight cement mortar 13 is placed below, that is, the lid 10.
Gradually accumulates from the top of Accordingly, the internal air is discharged from the exhaust hose 3 by an amount corresponding to the volume of the lightweight cement mortar 13 injected.

The same procedure can be performed irrespective of the angle of the bolt box. FIG. 4 assumes a bolt box in the vicinity of the lower side, and the cover member 10 is arranged so as to face upward. Then, as shown in FIG. 2A, the injection plug 2 and the exhaust plug 4 are attached, and at this time, they are arranged so that the base end of the exhaust hole 3 is located at the uppermost end (open end) in the acrylic box 8. . Next, as shown in FIG. 3B, the pump is operated to start injection and filling of the lightweight cement mortar 13, and the injected lightweight cement mortar 13 gradually accumulates from below, that is, from the upper surface of the back end plate. Go. Accordingly, the internal air is discharged from the exhaust hose 3 by an amount corresponding to the volume of the lightweight cement mortar 13 injected. FIG. 5 assumes a bolt box near the side, in which the lid 10 is arranged on the side. Then, the injection plug 2 and the exhaust plug 4 are attached as shown in FIG. 2A, but at this time, the base end of the exhaust hole 3 is arranged at the uppermost portion (near the opening end) in the acrylic box 8. did. Next, the pump is operated to start the injection and filling of the lightweight cement mortar 13 as shown in FIG. 3B, and the injected lightweight cement mortar 13 gradually accumulates from below. Accordingly, the internal air is discharged from the exhaust hose 3 by an amount corresponding to the volume of the lightweight cement mortar 13 injected. The following examples were performed using such an experimental apparatus.

<Example 1> A light-weight cement mortar having the composition shown in Table 1 was used for injection filling (filling batch test) in an experimental apparatus using the above-mentioned acrylic box (withstand pressure of 3 kgf / cm ² ). , Its fluidity (fillability)
And the compressive strength, shrinkage, water permeability and the like after curing were measured.

[0036]

[Table 2]

Example 2 "Example (composition example)" in Table 2
Using lightweight cement mortar of 11 ", assuming or using an actual bolt box, using fly ash reinforced nylon panel (Matsumura Seisakusho Co., Ltd.) as lid material,
Various tests were performed. The test methods were [0018] to [0
023] and the test method described in [0014]. The test results are shown below.

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

· Shrinkage rate of mortar material 4W Shrinkage rate 0.03625%

[0042]

[Table 6]

[0043]

[Table 7]

Water absorption test (according to JIS A 1404 Test Method for Cement Waterproofing Agent for Buildings) Permeability 3.0 g

[0045]

[Table 8]

[0046]

[Table 9]

[0047]

[Table 10]

[0048]

[Table 11]

[0049]

[Table 12]

-Air content of mortar 10% when kneading one bag (25 kg) of mixed mortar with a water content of 5.7 liters-Breathing test of mortar (according to JIS A 1123) No breathing is observed.

[0051]

As described above, the lightweight cement mortar of the present invention and the method for filling a bolt box using the same can be easily filled into a bolt box without gaps, thereby improving workability and reducing labor costs. Can result in reductions. Further, since it has the same strength as the concrete segment, it does not become a weak point at least as an underground pipe, and there is no problem even if any external stress acts.

In addition, by using a lightweight cement mortar in which the amount of cement, lightweight aggregate, etc. is specified,
It is possible to eliminate all problems in construction and quality of the conventional air mortar method, quick-setting mortar method, lightweight mortar method, hard foam urethane method and the like.

[Brief description of the drawings]

FIG. 1 is a front view and a plan view showing an injection plug and an exhaust plug used in an example.

FIG. 2 is a front view and a plan view showing an acrylic box used in an example.

FIG. 3A is a front view showing a state immediately after a pump is operated in an embodiment, and FIG. 3B is a front view showing a state in which lightweight cement mortar is somewhat accumulated.

FIG. 4A is a front view showing a state immediately after the pump is operated in the embodiment, and FIG. 4B is a front view showing a state in which lightweight cement mortar is somewhat accumulated.

5A is a front view showing a state immediately after the pump is operated in the embodiment, and FIG. 5B is a front view showing a state in which the lightweight cement mortar is somewhat accumulated.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) // (C04B 28/02 14:02 16:06) 111: 40 (71) Applicant 595115488 Matsumura Manufacturing Co., Ltd. Kita, Osaka 5-1-2, Toyosaki-ku, Tokyo (72) Junichi Muramatsu 2-5-8 Kita-Aoyama, Minato-ku, Tokyo Intra-company group (72) Inventor Takuo Nakahira 2-58-8 Kita-Aoyama, Minato-ku, Tokyo Stock (72) Inventor Susumu Harada Inventor Fujikawa Building Materials Industry Co., Ltd., 13-13 Torihama-cho, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture Inside the company (72) Inventor Masanori Takagi 2-13-2, Hatchobori, Chuo-ku, Tokyo Domino Building 4F Inside Shoresin Co., Ltd. (72) Inventor Kota Matsumura 5-1-2 Toyosaki, Kita-ku, Osaka-shi, Osaka F-term (reference) in Shamatsumura Works 2D055 AA01 AA04 AA06 GC05 GC06 KA00 4G012 PA04 PA10 PA24 PB27 PC03 PC08 PC12 PE07 4G055 AA 03 AB07 AC08 BA35 EA01 FA01

Claims (4)

[Claims] 1. A lightweight cement mortar for filling a closed space formed by fixing a lid material so as to close a bolt box, wherein the specific gravity of the composition at the time of injection is 0.5 to 1.
9. A lightweight cement mortar for a bolt box filling method, which has a flow value of 140 to 210 mm and, when hardened, produces a strength equal to or higher than that of a concrete segment. 2. A cement comprising 20 to 85% by weight, a lightweight aggregate of 0.1 to 5% by weight, an inorganic admixture of 5 to 80% by weight,
2. The lightweight cement mortar for a bolt box filling method according to claim 1, comprising 0.2 to 5 wt% of an organic admixture. 3. 3. A lid material is fixed so as to close the bolt box, an injection plug of lightweight cement mortar is attached to an injection port formed in the lid material, and internal air is exhausted into an exhaust port formed in the lid material. An exhaust plug was attached, the specific gravity of the composition at the time of injection was 0.5 to 1.9, and the flow value was 140.
A lightweight cement mortar, which is about 210 mm and has the same strength as the concrete segment or more when hardened, is pumped by a pump, and a positive pressure of 0.5 to 3.0 kgf / cm is injected into the bolt box from the injection plug. ²⁾ Fill the bolt box with light-weight cement mortar, fill the bolt box with light-weight cement mortar, and remove the injection plug and exhaust plug. Construction method. 4. The lightweight cement mortar is made of cement 20.
~ 85wt%, lightweight aggregate 0.1 ~ 5wt%, inorganic admixture 5 ~ 80wt%, organic admixture 0.2 ~ 5wt
The method for filling a hole in a bolt box using a lightweight cement mortar according to claim 3, wherein