JP2989567B2 - Composition for filling material and filling material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filling material for electric conduits, and more particularly, to a pumping material having excellent pumping properties and self-filling properties.
The present invention relates to a filling material for an electrical conduit having a low breathing rate, a low calorific value and a low thermal resistance.

2. Description of the Related Art Electrical conduits buried in the ground by non-cutting method such as propulsion method or open-cutting method (about 70-150 cm in diameter)
Inside, are installed about 9 to 15 power transmission tubes (about 10 to 15 cm in diameter) for passing a power transmission cable through a spacer, and as a material for filling a gap between these power transmission pipes and a circuit pipe, An inlay is used.

[0003] The above-mentioned power cable underground laying work is generally performed by the following steps. Install conduits underground. The power transmission tube is installed and fixed inside the conduit tube using spacers arranged at appropriate intervals in the longitudinal direction (at this stage, the power transmission cable is not inserted into the power transmission tube). The gap between the power transmission tube and the electric line tube is filled with a filling material. After the filled filling material has hardened and the temperature has decreased to some extent (normally, about one month after filling the filling material), a power transmission cable having an outer diameter slightly smaller than the inner diameter of the power transmission tube is inserted into the power transmission tube.

The filling material used in the underground construction work of the power transmission cable can achieve a desired pressure feeding distance at the time of filling, and an air layer having a high thermal resistance value is not formed at a lower portion of the power transmission tube or the like due to a breathing phenomenon after filling. It is required that the power transmission cable have a strength necessary for inserting the power transmission cable and support the power transmission tube, and that the heat generated by the power transmission cable be appropriately radiated during use. In consideration of such points, the following characteristics are generally required for the conventional filling material for conduit tubes.

(1) Before curing (1-1) The flow down time of the P funnel is required to be within 25 seconds. By doing so, the distance in which the filling material can be filled and pumped at one time can be increased, the amount of pumping can be increased, the load pressure of the pump during the pumping can be further reduced, the filling property is good, and the filled filling can be performed. This is because voids generated inside the material can be reduced. P funnel flow time is 10-20
Preferably, it is seconds. If the time is set to 20 seconds or less, the above-mentioned effect becomes more favorable. On the other hand, if the time is set to less than 10 seconds, the viscosity of the filling material becomes too low, and the material may be separated.

(1-2) The breathing rate is required to be 2% or less. If the breathing rate is greater than 2%, a breathing phenomenon (a phenomenon in which moisture moves upward, or one of material separation phenomena) may occur after the casting of the filling material, and a gap may be formed below the power transmission tube. .

(2) After curing (2-1) The thermal resistance value is required to be 100 ° C. · cm / W or less. This is because the heat generated from the power transmission cable when the power transmission cable is used needs to be appropriately radiated to the ground outside the conduit via the filling material. If the thermal resistance value is higher than 100 ° C./cm/W, the heat generated from the power transmission cable cannot be appropriately dissipated into the soil, and the power transmission amount decreases due to a rise in the temperature of the power transmission tube.

(2-2) It is required that the 7-day strength is 0.5 N / mm ² or more. It is required to securely fix the power transmission tube when passing the power transmission cable through the power transmission tube.

[0009]

2. Description of the Related Art The following fillers have been conventionally used for the above purpose. (1) It is called cement bentonite milk (CB milk) composed of cement and bentonite, and its composition is about 750 kg / m ^{3 of} cement and 30 kg /
m ³ approximately, in-filling material having a composition of about water 750 kg / m ^3. (2) A mortar containing cement and sand mixed with a fine powder admixture and air-filled material (Japanese Patent Publication 2-16)
644).

[0010]

The filling material shown in the above (1) and (2) satisfies the characteristics required for the filling material described above, but on the other hand, the filling material (1) In (2), since the unit cement amount is large, the calorific value due to the hydration reaction at the time of hardening is large (the cumulative calorific value is large, about 70 to 80 cal / g), and there is a problem that the temperature rise inside the conduit is large. The need to withstand such temperature rises limits the materials that can be used for the power transmission tubes. For example, if the power transmission tube is made of plastic or the like having low heat resistance, it cannot be used because it is deformed by heat. Further, since the temperature inside the conduit increases, it takes time for the temperature inside the conduit after filling to decrease to the temperature suitable for insertion of the power transmission cable, and the delay in proceeding to the subsequent process is delayed.

On the other hand, even in the case of the filling material (2) described in JP-B-2-16644, since the unit cement amount is large, as in the case of the filling material (1), heat is generated by a hydration reaction at the time of curing. Large amount (about 30-40 cal / g),
The temperature inside the conduit is large. Therefore, it takes time for the inside temperature of the conduit to fall to the temperature suitable for insertion of the power transmission cable even after the filling with the filling material (2), so that there is a disadvantage that the process is delayed in the subsequent process. for that reason,
There is a problem that the time required for the final construction period until the power transmission cable is laid on the power transmission tube in the power line tube becomes long.

[0012] The present invention can reduce the amount of heat generated during curing without losing the excellent advantages of the conventional filling material, thereby making it possible to reduce the amount of heat required to lay the power transmission cable in the power transmission tube in the power line tube. An object of the present invention is to provide a composition for a filling material for an electric conduit and a filling material that can reduce the time required for the construction period.

[0013]

The filling material for an electric conduit according to the present invention comprises a hydraulic powder, a swelling clay, an admixture, and water. Is 2% or less, the 7-day strength is 0.5 N / mm ² or more,
It is characterized in that the thermal resistance value is 100 ° C. · cm / W or less and the integrated heat generation up to 7 days of material age is 20 cal / g or less.

The filling material for an electrical conduit according to the first invention of the present application is 100 parts by weight of a filling material composition comprising 10 to 20% by weight of hydraulic powder, 4 to 10% by weight of swelling clay, and the remainder being an admixture. On the other hand, it is preferable that water comprises 70 to 80 parts by weight, and the admixture comprises at least one admixture selected from blast furnace slag powder pozzolan and rock powder. In addition, the composition for an electric line pipe filling material used for the electric line pipe filling material of the first invention of the present application is a composition for an internal filling material composed of hydraulic powder, an admixture, and a swelling clay, wherein the admixture is Blast furnace slag powder, pozzolan, and at least one admixture selected from rock powder, hydraulic powder 10 to 20% by weight, swelling clay 4 to 10% by weight, balance admixture It is characterized by.

The composition for the filling material and the filling material of the present invention comprise:
The calorific value at the time of curing is reduced without losing the properties of the filling material which has been considered necessary in the past, that is, the integrated calorific value from before curing to at the time of curing is set to 20 cal / g or less. This is to prevent the internal temperature of the filling material from rising due to the heat generated in the filling material when the filling material is cured, and to prevent the temperature of the power transmission tube from rising. If the accumulated heat value exceeds 20 cal / g, it takes time to lower the internal temperature of the filling material, and it is delayed to move to the next step such as the next transmission line insertion step. In addition, the integrated calorific value in the present invention is a value measured by a calorie meter.

Preferred embodiments of the wire filling material and the wire filling composition of the present invention include the following. As long as no inconsistency arises, a preferred embodiment of the plugging material for a conduit tube of the present invention also includes a mode in which the following (1) and (2) are combined.

(1) The swelling clay is A. C. Method C (Am
An inlaying material for an electrical conduit, which is a bentonite having a degree of swelling of 5 to 40 according to the standard of Eric Collin Company. (2) A filling material for a conduit tube, wherein the swellable clay is bentonite in which particles having a particle size of 2 μm or less measured by an Andreazen pipette are 80% by weight or more.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A. First, the components of the composition for a wire filling material of the present invention will be described. (1) Hydraulic powder Hydraulic powder includes ordinary Portland cement, early strength Portland cement, moderate heat Portland cement,
Portland cement such as low heat cement, mixed cement such as blast furnace cement and fly ash cement, recycled cement from raw corn sludge, cement dust, lime-based solidifying material (for example, Asano Clean Set CS-10 etc. as a commercial product), Gypsum-based solidifying materials (gypsum gypsum, hemihydrate gypsum, anhydrous gypsum and any mixture thereof) may be mentioned.

(2) Admixture Although the main material of the composition for the filling material of the present invention is an admixture, it is conventionally considered to be mainly a hydraulic powder, and is referred to as an admixture in the sense of a material that is admixed with this. And (2-1) As the admixture, an admixture of at least one selected from blast furnace slag powder, pozzolan and rock powder is used. The Brain value of the admixture is 1500-
It is preferably 5000 cm ² / g. (2-2) Pozzolan is a powder containing a siliceous substance that reacts with calcium hydroxide or the like to form insoluble calcium silicate by the pozzolanic reaction, and includes coal ash, silica fume, volcanic ash, clay silicate, diatomaceous earth, and the like. Is mentioned. Among them, coal ash is a substantially spherical powder and is preferable because the amount of water can be reduced. As coal ash, thermal power plants, etc.
For example, fly ash dry ash generated from a pulverized coal combustion furnace, JI obtained by classifying the fly ash dry ash and adjusting the particle size
S fly ash or the like can be used. Also, waste materials such as incineration ash can be used. (2-3) As the rock powder, limestone powder, quartz powder,
Hard sandstone powder can be obtained.

(3) Swellable clay (3-1) Swellable clay is described in A.I. C. Method C (Americic
An swelling degree of 5 to 40 according to an anodizing method of the present invention is preferable. Particularly, bentonite which is inexpensive and easily available is preferred. A larger degree of swelling is advantageous in terms of cost because the bleeding rate can be reduced with a small amount. On the other hand, if the degree of swelling exceeds 40, the amount of water increases, which is not preferable.

(3-2) The use of bentonite containing 80% by weight or more of particles having a particle size of 2 μm or less measured with an Andreazen pipette as the swellable clay can reduce the breathing rate with a smaller amount of bentonite. Is more preferable.

(3-3) Bentonite has a different particle size composition depending on the place of origin and ore vein. The larger the degree of swelling is, the smaller the particle size tends to be. It is particularly noted that 80 wt. % Or less of bentonite is commercially available. The particles having a particle diameter of 2 μm or less
Examples of the bentonite that satisfies the condition of not less than% by weight include bentonite naturally produced in Wyoming, USA (degree of swelling: 25 to 30). (Incidentally, in the case of naturally occurring bentonite produced in Japan, the proportion of particles having a particle diameter of 2 μm or less is about 50 to 70% by weight in the case of swelling degree of 25 to 30.) Bentonite having a particle diameter larger than the above particle diameter is pulverized. It is possible to adjust the particle size to a specified particle size, but from the industrial and economical point of view, it is preferable to use naturally occurring and commercially available bentonite.

(3-4) The particle size of bentonite is measured using an Andreazen pipette. This is because the difference in particle size of bentonite is unclear in the particle size obtained by another measurement method. The measurement by the Andreazen pipette belongs to the liquid phase dispersion sedimentation method, and the suspension in the sedimentation tube in which the powder sample is dispersed is subjected to a predetermined depth of the sedimentation tube at every time calculated in advance for a specific particle diameter. From the suspension, and the powder in the dispersion is weighed. In this case, water is generally used for measuring a powder sample that does not undergo hydration reaction as a dispersion medium, and a small amount of sodium hexametaphosphate or the like is used as a dispersant.

(3-5) Further, the conditions for measurement with an Andreazen pipette will be described. A suspension in which 3% by weight or less, preferably 1 to 2% by weight of bentonite is dispersed in an aqueous solution containing distilled water as a dispersion medium and sodium hexametaphosphate (about 0.2% by weight) as a dispersant. And measure. In this case, if the concentration of bentonite in the suspension exceeds 3% by weight, the particle concentration increases and the distance between the particles becomes too close. As a result, the mutual particles affect the sedimentation, resulting in an error in the measured value. Absent.
(By the way, the time required for measuring fine bentonite usable in the present invention with an Andreazen pipette is 2 hours.
It is slightly more than 7 hours at μm. )

B. Next, the reason for the limitation of the preferred composition of the composition for an electric wire tube insert material and the insert material of the present invention will be described. (1) Hydraulic Powder Hydraulic powder is contained in a composition for an infill material composed of hydraulic powder, swelling clay, and at least one admixture selected from blast furnace slag powder, pozzolan and rock powder. --20
% By weight. If the amount of the hydraulic powder is less than 10% by weight, the strength in 7 days is low, and
The thermal resistance also increases. On the other hand, the hydraulic powder is 20% by weight.
When it exceeds, the integrated heat generation amount becomes large.

(2) Swellable clay It is preferable that the swellable clay is contained in the composition for the filling material in an amount of 4 to 10% by weight. 4% by weight of swelling clay
If it is less than 3, the breathing rate increases. On the other hand, if it exceeds 10% by weight, it is somewhat difficult to make the P funnel flow time within 25 seconds.

(3) Admixture The admixture is composed of at least one selected from blast furnace slag powder, pozzolan and rock powder, and is contained in an amount of 75 to 85% by weight based on the above-mentioned filling material composition. Is preferred. If the amount of the admixture is less than 75% by weight, the accumulated heat generation becomes large (this case corresponds to the case where the amount of the hydraulic powder is large), and it is difficult to make the P funnel flow time within 25 seconds. (In this case, this applies when the amount of swelling clay is large). On the other hand, if it exceeds 85% by weight,
The strength after 7 days is low, and the heat resistance value is high (this case corresponds to the case where the amount of hydraulic powder is small).

(4) Water 70 parts by weight of water is added to 100 parts by weight of the
Preferably, it is contained in an amount of up to 80 parts by weight. If the amount of water is less than 70 parts by weight per 100 parts by weight of the filling material composition,
It is difficult to make the flow time of the P funnel fall within 25 seconds, and if it exceeds 80 parts by weight with respect to 100 parts by weight of the filling material composition, the thermal resistance value increases and the strength in 7 days decreases. I do.

C. The following conventional method (kneading method) is used to produce the wire filling material of the present invention, but the method of producing the wire filling material of the present invention is not limited to these methods. (1) A method in which hydraulic powder, admixture, swelling clay, and water are collectively charged into a mixer and kneaded to produce a filling material for a conduit, (2) A swelling clay and water are charged into a mixer. A method of producing a slurry by kneading, adding a hydraulic powder and an admixture to the slurry, and further kneading the mixture to produce a filling material for a conduit.

Among these methods, there is a method in which the hydraulic powder, admixture, swelling clay and water shown in the above (1) are collectively charged into a mixer and kneaded to produce a filling material for a conduit tube. This is a preferable production method because the kneading time can be shortened. In this case, the hydraulic powder, admixture, and swelling clay may be mixed (premixed) before being charged into the mixer, or may be separately charged into the mixer.

D. According to the present invention, the filling material for a conduit tube is filled and solidified between the conduit tube and the power transmission tube according to a normal method such as pumping after the power transmission tube is installed and fixed using a spacer in the conduit tube. Is not limited to a specific construction method.

[0032]

According to the present invention, heat generation is almost completed within 7 days after filling, the calorific value is small, and
Since it expresses a compressive strength of 0.5 N / mm ² or more per day,
It is possible to shorten the period from the filling of the filling material to the next step of passing the power transmission cable through the power transmission tube. Moreover, since the self-filling property is excellent, the breathing rate is small, and the thermal resistance is small, the heat generated by the power transmission cable can be radiated into the soil.

[0033]

The present invention will be described in more detail with reference to the following examples.

1. Materials used Materials used are as follows. (1) Hydraulic powder: ordinary Portland cement (manufactured by Nippon Cement Co., Ltd.) (2) Admixture: coal ash A: Kyushu Electric Power Co., Inc. Matsuura Thermal Power Station Coal ash raw powder (Hunter Valley coal combustion) Ash, Blaine value 3400 cm ² / g), Coal ash B: Electric Power Development Co., Ltd.
Fly ash produced by Isogo Thermal Power Station (JIS standard product, Brain value: 4060 cm ² / g), blast furnace slag;
"Serament" manufactured by Daiichi Cement Co. (Brain value 3700
cm ² / g), limestone powder; trade name “Filler TR20
0 "manufactured by Okutama Mining Co., Ltd. (Brain value: 2000 cm / g) (3) Swellable clay: Bentonite A ... Trade name:" Super Clay ", a commercially available product from Toyshun Yoko Co., Ltd. (Wyoming, U.S.A.); Ratio 81.1% by weight (Note 1), Swelling degree: 27 (Note 2): Bentonite B
・ ・ Product name: “Premium gel” manufactured by Kanto Bentonite Mining Co., Ltd., ratio of particle diameter 2 μm or less; 60.8% by weight, swelling degree 30 (4) Water: tap water

(Note 1) The particle size of bentonite was measured as follows. Sodium hexametaphosphate
4. Bentonite is added to 350 ml of distilled water in which 0 g is dissolved.
Add 0 g, stir and disperse for 30 minutes, leave still in a constant temperature water bath at 25 ° C., add distilled water at 25 ° C. to 500 ml,
The suspension was prepared by shaking well.

The obtained suspension was put into a pipette settling tube of an Andreazen pipette, a pipette capillary was inserted, and the liquid surface was adjusted to the marked line, followed by shaking for 1 minute and allowed to stand still. The measurement was started when the sample was left standing, and after 7 hours, 11 minutes, and 59 seconds, in order to measure the ratio of particles having a particle size of 2 μm or less,
10 ml of the suspension was collected in 14 seconds. The fractionated solution was dried (110 ° C.), cooled and weighed, and then the particle ratio (% by weight) was calculated. (Note 2): The same applies hereinafter, measured according to the ACC method.

(Examples and Comparative Examples) According to the composition shown in Table 1, the above materials were mixed with a Hobart mixer (0.005 m ³ ).
And kneaded for 2 minutes to prepare a filling material. The following infill materials were measured for the following properties 1) to 5), and the results are shown in Table 1.

1) Flowdown time (seconds) of P funnel: Measured according to "Japan Road Public Corporation Standard A 313 (Test method for air mortar and air milk)". 2) Breathing rate (%): “Japan Highway Public Corporation Standard A
313 (Test method for air mortar and air milk) ". 3) Cumulative calorific value (cal / g): The calorific value (MMC-5116) manufactured by Tokyo Riko Co., Ltd. was measured at 20 ° C for up to 7 days. 4) Thermal resistance (° C./cm/W: 7 days of material age): “JIS
The thermal conductivity was measured according to R 2618 (Test method for thermal conductivity of refractory adiabatic brick by hot wire method), and the reciprocal thereof was calculated. 5) Compressive strength (N / mm ² : 7 days old): φ5 × 10c
Each of the filling materials was poured into a m formwork, mixed and cured in a moist air at 20 ° C., and the compressive strength was measured in accordance with “JIS A 1108 (Method of testing compressive strength of concrete)”.

[0039]

[Table 1]

(Experiment on actual structure) Formulation of Example 11 in Table 1
According to the above, each material was mixed with a two-shaft forced stirring mixer (4
m ^Three), And kneaded for 2 minutes to prepare a filling material.
The characteristics of the above 1) to 5) were measured for the filling material. Also,
Using a pump truck (squeeze type), insert
24m conduit (diameter 70cm, diameter 10cm)
Installed via 9 spacers (spacer
The interval was 2 m)). 10 days later, 2m, 12m,
It cut | disconnected at the position of 22 m, and the filling condition of the filling material was confirmed.
The pumping pressure of the pump is 45 kgf / cm^TwoAnd Conclusion
The results are shown in Table 2.

[0041]

[Table 2]

Further, the filling material having the above-mentioned composition was filled with an inner diameter of 51 m.
m into a vinyl chloride pipe (length 400 m) from one end (pumping pressure of the pump is 45 kgf / cm ² )
Long distance pumpability was investigated. As a result, it was confirmed that the filling material flowed out from the other end opposite to the pouring port, and that the long-distance pumpability was good. In addition, the characteristics 1) to 5) were measured for the intermediate material flowing out from the other end. Table 3 shows the results.

[0043]

[Table 3] From Table 3, there was almost no change in the properties of the filling material even after long-distance pumping.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 18:08 14:10)

Claims (7)

(57) [Claims] 1. A hydraulic powder, a swellable clay, an admixture and water.
The P funnel flow time is 25 seconds or less, the breathing rate is 2% or less, the 7-day strength is 0.5 N / mm ² or more, the thermal resistance value is 100 ° C./cm/W or less, and the accumulation up to 7 days of material age A filling material for an electrical conduit, wherein the calorific value is 20 cal / g or less. 2. 70 to 80 parts by weight of water based on 10 to 20% by weight of a hydraulic powder, 4 to 10% by weight of a swelling clay, and 100 parts by weight of a filling material composed of an admixture. 2. The filling material for a conduit according to claim 1, wherein said admixture comprises at least one admixture selected from blast furnace slag powder, pozzolan, and rock powder. 3. The method of claim 1, wherein the swelling clay is A.I. C. Method C (Ameri
The filling material for a conduit tube according to claim 1 or 2 , which is a bentonite having a swelling degree of 5 to 40 according to a Can Collided Company standard. 4. The swellable clay, claim the following particle diameter 2μm, measured by the Andreasen pipette is bentonite, which is composed of 80 wt% or more 1, 2 or 3
The inlaying material for the conduit described. 5. A composition for a filling material comprising a hydraulic powder, an admixture, and a swelling clay, wherein the admixture comprises at least one admixture selected from blast furnace slag powder, pozzolan, and rock powder. 2. The composition for an electric line tube according to claim 1, wherein the hydraulic powder is 10 to 20% by weight, the swelling clay is 4 to 10% by weight, and the balance is an admixture. 3. 6. The swelling clay according to claim 1, wherein the swelling clay is A.I. C. Method C (Ameri
The composition for a filling material for an electric conduit according to claim 5, wherein the composition is bentonite having a swelling degree of 5 to 40 according to a Can Collid Company standard. 7. The composition according to claim 5, wherein the swellable clay is bentonite composed of 80% by weight or more of particles having a particle size of 2 μm or less as measured by an Andreazen pipette.