Cavity filler composition, cavity filler, method for manufacturing cavity filler, and cavity filling method

Abstract

To provide a cavity filler composition capable of suppressing leakage from gaps while maintaining sufficient fluidity, a cavity filler containing the cavity filler composition, a method for manufacturing the cavity filler, and a cavity filling method using the cavity filler. [Solution] The cavity filling material composition according to the present invention comprises dried sludge powder, blast furnace slag powder, and bentonite, wherein the swelling power of the bentonite is 13.0 mL / 2 g or more, the content of the dried sludge powder is 20% by mass or more and 85% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder, the content of the blast furnace slag powder is 15% by mass or more and 80% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder, and the content of the bentonite is more than 40% by mass and 60% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder.

Description

[Technical Field]

[0001] The present invention relates to a cavity filler composition, a cavity filler, a method for producing a cavity filler, and a cavity filling method. [Background technology]

[0002] Conventionally, the reuse of concrete sludge (hereinafter also simply referred to as "sludge") generated from ready-mix concrete plants and the like as a material for cavity fillers has been considered. However, since this sludge is a muddy industrial waste consisting mainly of cement paste and fine aggregate particles, it contains a large amount of moisture, and as a result, cavity fillers containing this sludge suffer from a decrease in fluidity due to the hydration of the cement. Therefore, in order to suppress this decrease in fluidity, dried sludge powder obtained by drying and crushing the sludge has been used (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-44123 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, conventional cavity fillers containing dried sludge powder, while highly fluid and easy to apply, had the problem of leaking out through gaps in the application area.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a cavity filler composition that can provide a cavity filler that can suppress leakage from gaps while maintaining sufficient fluidity, a cavity filler containing the cavity filler composition, a method for manufacturing the cavity filler, and a cavity filling method using the cavity filler. [Means for solving the problem]

[0006] The cavity filling material composition according to the present invention comprises dried sludge powder, blast furnace slag powder, and bentonite. The swelling capacity of the bentonite is 13.0 mL / 2 g or more. The content of the dried sludge powder is 20% by mass or more and 85% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder. The content of the blast furnace slag powder is 15% by mass or more and 80% by mass or less, relative to the total content of the dried sludge powder and the blast furnace slag powder. The bentonite content is greater than 40% by mass and less than or equal to 60% by mass of the total content of the dried sludge powder and the blast furnace slag powder.

[0007] The cavity filler composition, having a swelling power of 13.0 mL / 2 g or more for the bentonite, can maintain sufficient fluidity to allow the cavity filler to penetrate gaps while exhibiting sufficient filling properties to retain the cavity filler within the gaps when mixed with water to form a cavity filler. Furthermore, the cavity filler composition, having a dry sludge powder content of 20% to 85% by mass relative to the total content of the dry sludge powder and the blast furnace slag powder, a blast furnace slag powder content of 15% to 80% by mass relative to the total content of the dry sludge powder and the blast furnace slag powder, and a bentonite content of more than 40% to 60% by mass relative to the total content of the dry sludge powder and the blast furnace slag powder, can ensure sufficient fluidity for the cavity filler to penetrate gaps under its own weight. Therefore, the cavity filler composition can provide a cavity filler that can suppress leakage from gaps while maintaining sufficient fluidity.

[0008] The cavity filling material composition according to the present invention has a Blaine specific surface area of ​​10,000 cm² of the dried sludge powder. 2 It may be more than / g.

[0009] According to such a configuration, the cavity filling material composition exhibits excellent fluidity in a state where it is mixed with water to form a cavity filling material, and can suppress the occurrence of material separation (bleeding) between water and the powder (the dried sludge, the blast furnace slag powder, and the bentonite).

[0010] The cavity filling material composition according to the present invention may have a Blaine specific surface area of the blast furnace slag powder of 3,500 cm 2 / g or more.

[0011] According to such a configuration, the cavity filling material composition can exhibit excellent fluidity in a state where it is mixed with water to form a cavity filling material.

[0012] The cavity filling material according to the present invention contains the above-described cavity filling material composition and water, and the water-powder ratio is 200% or more and 250% or less.

[0013] Due to the swelling force of the bentonite in the cavity filling material being 13.0 mL / 2 g or more and the water-powder ratio being 200% or more and 250% or less, the cavity filling material can maintain sufficient fluidity to enter the gaps and also exhibit sufficient filling properties to retain the cavity filling material within the gaps. Therefore, it can suppress leakage from the gaps while maintaining sufficient fluidity.

[0014] The method for manufacturing the cavity filling material according to the present invention is a method for manufacturing the above-described cavity filling material, and includes a step of kneading dried sludge powder, blast furnace slag powder, bentonite, and water.

[0015] According to such a configuration, the method for manufacturing the cavity filling material can manufacture a cavity filling material that can suppress leakage from the gaps while maintaining sufficient fluidity.

[0016] The cavity filling method according to the present invention fills the above-described cavity filling material into the cavity portion.

[0017] With this configuration, the cavity filling method can be carried out while maintaining sufficient fluidity of the cavity filling material and suppressing leakage from gaps. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a cavity filler composition that can suppress leakage from gaps while maintaining sufficient fluidity, a cavity filler containing the cavity filler composition, a method for manufacturing the cavity filler, and a cavity filling method using the cavity filler. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic diagram of the test apparatus used for the non-leakage test in the embodiment. [Modes for carrying out the invention]

[0020] The following describes the cavity filler composition, cavity filler, method for manufacturing the cavity filler, and cavity filling method according to this embodiment.

[0021] <Cavity filler composition> The cavity filling material composition according to this embodiment includes dried sludge powder, blast furnace slag powder, and bentonite.

[0022] Examples of bentonite include sodium-type bentonite, calcium-type bentonite, activated bentonite, and organic bentonite. Activated bentonite refers to calcium-type bentonite artificially converted to the sodium type by adding sodium carbonate. Organic bentonite refers to bentonite containing organic cations such as quaternary organic ammonium ions in its layered structure. The bentonite may be used individually or in combination of two or more types.

[0023] The swelling capacity of the bentonite is 13.0 mL / 2g or more, preferably 13.5 mL / 2g or more, and more preferably 16.0 mL / 2g or more, from the viewpoint of maintaining sufficient fluidity while suppressing leakage from gaps when mixed with water and used as a cavity filler. The swelling capacity of the bentonite may be 30.0 mL / 2g or less, or 27.0 mL / 2g or less. The swelling capacity is determined by the swelling test method of the Japan Bentonite Industry Association Standard Test Method (JBAS-104-77).

[0024] The particle size of the bentonite, d10, may be 6.8 μm or more and 10.0 μm or less, 7.0 μm or more and 9.5 μm or less, or 8.0 μm or more and 9.2 μm or less.

[0025] Furthermore, the particle size of the bentonite, d50, may be 27.5 μm or more and 33.0 μm or less, 27.8 μm or more and 32.5 μm or less, or 30.0 μm or more and 32.0 μm or less.

[0026] In this specification, d10 refers to the particle size when the passing mass percentage is 10% in a particle size summing curve where the horizontal axis is particle size (μm) and the vertical axis is the passing mass percentage (%), and d50 refers to the particle size when the passing mass percentage is 50% in the same particle size summing curve.

[0027] The d10 and d50 values ​​of the bentonite are measured using a laser diffraction particle size distribution analyzer (for example, the MT3000 manufactured by Microtrac-Bel).

[0028] The bentonite content, when mixed with water to form a cavity filler, exhibits excellent fluidity while suppressing leakage from gaps. This is because the bentonite content is greater than 40% by mass and less than or equal to 60% by mass, preferably between 45% by mass and 55% by mass, relative to the total content of the dried sludge powder and the blast furnace slag powder.

[0029] Dried sludge powder can be obtained by recovering sludge water originating from residual concrete or returned concrete generated from ready-mix concrete plants, construction sites, etc., or from washing wastewater generated from ready-mix concrete plants, extracting the cake component (solid component) from the sludge water, and then drying and grinding the cake component. The sludge water refers to a slurry-like substance containing cement and fine aggregate (for example, fine aggregate with a particle size of less than 300 μm) as the solid component. The particle size of the fine aggregate refers to the value obtained by measurement using a laser diffraction particle size analyzer.

[0030] Examples of the aforementioned cements include Portland cements such as ordinary Portland cement, rapid-hardening Portland cement, ultra-rapid-hardening Portland cement, moderate-heat Portland cement, sulfate-resistant Portland cement, and white Portland cement; mixed cements such as fly ash cement and silica cement; and known cements such as ultrafast-setting cement and alumina cement. Note that one type of cement may be used alone, or two or more types may be used in combination.

[0031] The moisture content of the dried sludge powder is not particularly limited and may be, for example, 7% by mass or less, 6% by mass or less, or 5% by mass or less.

[0032] The moisture content of the dried sludge powder is calculated using the following formula (1). Moisture content (mass%) = 100 × (mass of water in the dry sludge powder) / {(Mass of completely dry sludge powder) + (Mass of moisture in the dry sludge powder)} ... (1)

[0033] The dried sludge powder may contain 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more of the cement or the compound derived from the cement. The remainder of the dried sludge powder includes, for example, fine aggregates (e.g., aggregates with a particle size of less than 300 μm). Examples of the compound derived from the cement include calcium hydroxide, calcium silicate hydrate, calcium aluminate hydrate, calcium carbonate, and the like.

[0034] From the perspective of exhibiting excellent fluidity and suppressing material separation (bleeding) between water and the solid content (the dried sludge, the blast furnace slag powder, and the bentonite) when mixed with water to form a void filler, the Blaine specific surface area of the dried sludge powder is preferably 10,000 cm 2 / g or more, more preferably 11,000 cm 2 / g or more. The Blaine specific surface area of the dried sludge powder may be 20,000 cm 2 / g or less, or may be 16,000 cm 2 / g or less.

[0035] The Blaine specific surface area of the dried sludge powder is measured according to the method described in JIS R 5201:2015, "Physical Testing Methods for Cement, 8 Powder Fineness Testing, 8.1 Specific Surface Area Testing".

[0036] The density of the dried sludge powder may be 2.4 g / cm 3 or more, may be 2.5 g / cm 3 or more, or may be 2.6 g / cm 3 or more. The density of the dried sludge powder may be 2.8 g / cm 3 or less, or may be 2.7 g / cm 3 or less.

[0037] The density of the aforementioned dried sludge powder is measured using a gas pycnometer (for example, a Cantachrome Ultra Pycnometer 1000) according to the method described in JIS R 5201:2015 "Physical Testing Methods for Cement, 7. Density Test" or the gas displacement method.

[0038] The particle size of the dried sludge powder, d10, may be 4.0 μm or more and 5.5 μm or less, 4.0 μm or more and 5.3 μm or less, or 4.0 μm or more and 5.0 μm or less.

[0039] Furthermore, the particle size of the dried sludge powder, d50, may be 10.0 μm or more and 30.0 μm or less, 15.0 μm or more and 25.0 μm or less, or 15.0 μm or more and 22.0 μm or less.

[0040] Furthermore, the particle size of the dried sludge powder, d90, may be 40.0 μm or more and 80.0 μm or less, or 50.0 μm or more and 75.0 μm or less.

[0041] In this specification, d90 refers to the particle size when the percentage of mass passing through a particle size summation curve, where the horizontal axis represents particle size (μm) and the vertical axis represents the percentage of mass passing through (%), is 90%.

[0042] The d10, d50, and d90 of the dried sludge powder are measured by the same method as the method for measuring the particle size of the bentonite.

[0043] The dried sludge powder may have a mass ratio of 45% or more, 48% or more, or 50% or more that passes through a sieve with a mesh size of 20 μm. Furthermore, the dried sludge powder may have a mass ratio of 80% or less, 70% or less, or 60% or less that passes through a sieve with a mesh size of 20 μm.

[0044] The dried sludge powder may have a mass ratio of 25% or more, 27% or more, or 29% or more that passes through a sieve with a mesh size of 10 μm. Furthermore, the dried sludge powder may have a mass ratio of 50% or less, 40% or less, or 35% or less that passes through a sieve with a mesh size of 10 μm.

[0045] The aforementioned dried sludge powder may have a mass loss rate W1 between 400°C and 500°C of 0.2% by mass or more and 5.0% by mass or less, or 0.3% by mass or more and 4.5% by mass or less, or 1.0% by mass or more and 4.0% by mass or less. Furthermore, the aforementioned dried sludge powder may have a mass loss rate W2 between 600°C and 800°C of 7.0% by mass or more and 20.0% by mass or less, or 7.8% by mass or more and 18.0% by mass or less, or 8.0% by mass or more and 15% by mass or less.

[0046] The mass loss rates W1 and W2 are determined from the thermogravimetric values ​​obtained by measuring the thermogravimetric values ​​under a nitrogen atmosphere at a heating rate of 10.0°C / min using a differential thermal-thermogravimetric simultaneous measurement device (for example, Rigaku Corporation's TG-8120).

[0047] From the viewpoint of obtaining sufficient fluidity, the content of the dried sludge powder is 20% by mass or more and 85% by mass or less, preferably 40% by mass or more and 60% by mass or less, relative to the total content of the dried sludge powder and the blast furnace slag powder.

[0048] Examples of blast furnace slag powder include granulated blast furnace slag powder and slowly cooled blast furnace slag powder. Granulated blast furnace slag powder refers to blast furnace slag obtained by rapidly cooling molten slag produced from a blast furnace by spraying it with a large amount of pressurized water, while slowly cooled blast furnace slag powder refers to blast furnace slag obtained by slowly cooling molten slag produced from a blast furnace by leaving it in a cooling yard.

[0049] The Blaine specific surface area of ​​the blast furnace slag powder is preferably 3,500 cm², from the viewpoint of obtaining excellent fluidity when mixed with water and used as a cavity filler. 2 It is 1 / g or more, and more preferably 3,800 cm 2 It is 1 / g or more, and more preferably 4,000 cm 2 It is 1 / g or more. Furthermore, the Blaine specific surface area of ​​the blast furnace slag powder is 10,000 cm². 2 It may be less than / g, or 8,000cm 2 It may be less than / g.

[0050] The Blaine specific surface area of ​​the blast furnace slag powder is measured in the same manner as the Blaine specific surface area of ​​the dried sludge powder.

[0051] The density of the blast furnace slag powder is 2.4 g / cm³. 3 It may be more than that, or 2.5 g / cm³ 3 It may be more than that, or 2.6 g / cm³ 3 The density may be higher than the above. Furthermore, the density of the blast furnace slag powder is 2.9 g / cm³. 3 It may also be less than 2.8 g / cm³. 3 It may also be less than 2.7 g / cm³. 3 The following is also acceptable.

[0052] The density of the blast furnace slag powder is measured in the same manner as the density of the dried sludge powder.

[0053] From the viewpoint of obtaining sufficient fluidity, the content of the blast furnace slag powder is 15% by mass or more and 80% by mass or less, preferably 40% by mass or more and 60% by mass or less, relative to the total content of the dried sludge powder and the blast furnace slag powder.

[0054] The cavity filler composition according to this embodiment comprises dried sludge powder, blast furnace slag powder, and bentonite, wherein the swelling power of the bentonite is 13.0 mL / 2 g or more, the content of the dried sludge powder is 20% by mass or more and 85% by mass or less relative to the total content of the dried sludge powder and the blast furnace slag powder, the content of the blast furnace slag powder is 15% by mass or more and 80% by mass or less relative to the total content of the dried sludge powder and the blast furnace slag powder, and the content of the bentonite is more than 40% by mass and 60% by mass or less relative to the total content of the dried sludge powder and the blast furnace slag powder. As a result, when mixed with water to form a cavity filler, the cavity filler can maintain sufficient fluidity to penetrate gaps while exhibiting sufficient filling properties to retain the cavity filler within the gaps. Therefore, it is possible to provide a cavity filler that can suppress leakage from gaps while maintaining sufficient fluidity.

[0055] The cavity filling material composition according to this embodiment has a Blaine specific surface area of ​​10,000 cm² of the dried sludge powder. 2 By having a concentration of 1 / g or more, the material exhibits excellent fluidity when mixed with water to form a cavity filler, and material separation (bleeding) between the water and the powder (the dry sludge, the blast furnace slag powder, and the bentonite) can be suppressed.

[0056] The cavity filling material composition according to this embodiment has a Blaine specific surface area of ​​3,500 cm² of blast furnace slag powder. 2 Having a concentration of 1 / g or higher allows for excellent fluidity when mixed with water to form a cavity filler.

[0057] <Cavity filling material> The cavity filler according to this embodiment comprises a cavity filler composition and water.

[0058] The cavity filler composition is the same as the cavity filler composition according to the present embodiment.

[0059] The water mentioned above is not particularly limited, and for example, tap water, industrial water, recovered water, groundwater, river water, rainwater, etc., can be used. Preferably, the water does not contain organic matter, chloride ions, sodium ions, potassium ions, etc., which adversely affect the hydration reaction of the cement composition and concrete, or if it does contain them, it is in extremely small amounts. It is more preferable that the water be tap water or industrial water of stable quality.

[0060] The water-to-powder ratio is 200% to 250%, preferably 210% to 240%, and more preferably 215% to 230%, from the viewpoint of maintaining sufficient fluidity while suppressing leakage from gaps. In the above water-to-powder ratio, "powder" refers to a mixture of dried sludge powder, blast furnace slag powder, and bentonite.

[0061] The wet density is 1.00 g / cm³. 3 It may be greater than or equal to 1.05 g / cm³. 3 It may be greater than or equal to 1.10 g / cm³. 3 It may be greater than or equal to 1.15 g / cm³. 3 It may be more than that, or 1.20 g / cm³ 3 The above is also acceptable. Furthermore, the wet density should be 1.50 g / cm³. 3 The following is also acceptable, or 1.40 g / cm³ 3 The following is also acceptable, or 1.30 g / cm³ 3 The following values ​​may also be used. By keeping the wet density within the above numerical range, the load on the ground in the cavity can be reduced, thereby suppressing further settlement. The wet density is measured in accordance with JIS A 1171:2016 "Test Methods for Polymer Cement Mortar" 6.4 Unit Volume Mass Test.

[0062] The cavity filler according to this embodiment may contain admixtures as needed. Examples of such admixtures include fly ash, silica fume, cement kiln dust, blast furnace fume, converter slag powder, hemihydrate gypsum, expansive agents, limestone powder, quicklime powder, dolomite powder, attapulgite, sepiolite, activated clay, acid clay, allophane, imogolite, shirasu (volcanic ash), shirasu balloon, kaolinite, metakaolin (calcined clay), synthetic zeolite, artificial zeolite, mordenite, clinoptilolite, and the like. Note that one type of admixture may be used alone, or two or more types may be used in combination.

[0063] The cavity filler according to this embodiment may contain admixtures as needed. Examples of admixtures include air-entraining agents, air-entraining water-reducing agents, thickeners, fluidizers, separation-reducing agents, setting retarders (e.g., tartaric acid), setting accelerators (e.g., aluminum sulfate), rapid setting agents, shrinkage-reducing agents, foaming agents, waterproofing agents, and the like. Note that one type of admixture may be used alone, or two or more types may be used in combination.

[0064] The cavity filling material according to this embodiment can be used not only to fill cavities through boreholes drilled from the ground surface toward cavities beneath the road surface, but also, for example, to fill cavities formed between the ground and sheet piles in tunnels constructed using the sheet pile method; or to fill cavities in various locations where backfilling with soil, sand, etc., is not possible.

[0065] The cavity filler according to this embodiment contains the above-mentioned cavity filler composition and water, and the water-to-powder ratio is 200% to 250%. This allows the material to maintain sufficient fluidity to penetrate gaps while also exhibiting sufficient filling properties to retain the cavity filler within the gaps. Thus, leakage from gaps can be suppressed while maintaining sufficient fluidity.

[0066] <Method for manufacturing cavity filler material> The method for manufacturing the cavity filler according to this embodiment is the method for manufacturing the cavity filler described above.

[0067] The method for producing the cavity filler according to this embodiment includes the step of kneading dried sludge powder, blast furnace slag powder, bentonite, and water.

[0068] The above process can be carried out, for example, by kneading the cavity filling composition containing the dried sludge powder, the blast furnace slag powder, and the bentonite with water, and optionally with an admixture and an admixture using a kneader.

[0069] The dried sludge powder, the blast furnace slag powder, and the bentonite are the same as those in the cavity filler composition according to the present embodiment. That is, the cavity filler composition is the same as the cavity filler composition according to the present embodiment.

[0070] The water is the same as that used in the cavity filling material according to the present embodiment.

[0071] Examples of the aforementioned mixing machines include hand mixers and grout mixers.

[0072] From the viewpoint of making it easy to transport to the construction site, the aforementioned hand mixer is preferably a small hand mixer.

[0073] The aforementioned hand mixer is equipped with a stirring blade. Examples of the shape of the stirring blade include a crown shape, a screw shape, and the like.

[0074] Examples of materials for the stirring blade include stainless steel and aluminum.

[0075] The diameter of the stirring blade may be 90 mm or more and 200 mm or less, or 100 mm or more and 180 mm or less.

[0076] As the aforementioned hand mixer, commercially available products such as the UT2204 (manufactured by Makita Corporation) can be used.

[0077] In the above process, the rotational speed of the kneader may be 400 rpm or more, or 600 rpm or more. Furthermore, the rotational speed of the kneader may be 1000 rpm or less, or 800 rpm or less.

[0078] In the above process, the kneading time may be 5 minutes or more and 10 minutes or less, or 3 minutes or more and 8 minutes or less.

[0079] Furthermore, when adding an admixture, the above step may be carried out by mixing the cavity filler composition and the water and then adding the admixture, or by adding the water to a premix powder containing the cavity filler composition and the admixture.

[0080] The method for manufacturing the cavity filler according to this embodiment is a method for manufacturing the cavity filler described above, and by including a step of kneading dried sludge powder, blast furnace slag powder, bentonite, and water, it is possible to manufacture a cavity filler that can suppress leakage from gaps while maintaining sufficient fluidity.

[0081] <Cavity filling method> The cavity filling method according to this embodiment involves filling the cavity with a cavity filling material.

[0082] The cavity filling method according to this embodiment is carried out, for example, at the construction site, by mixing a cavity filling material composition, water, and, if necessary, an admixture and an admixture using a kneader to produce a cavity filling material, filling the resulting cavity filling material into the cavity at the construction site using, for example, a pump, and hardening the cavity filling material.

[0083] The cavity filler is the same as the cavity filler according to the present embodiment described above.

[0084] Furthermore, the cavity filler composition is the same as the cavity filler composition according to the present embodiment.

[0085] Furthermore, the method for manufacturing the cavity filler is the same as the method for manufacturing the cavity filler according to the present embodiment.

[0086] The volume of the cavity filler after mixing the cavity filler composition with water may be 1.80 L or more, or 2.00 L or more, per 1 kg of the cavity filler composition. Alternatively, the volume of the cavity filler may be 2.40 L or less, or 2.30 L or less.

[0087] The curing time after filling the cavity with the aforementioned cavity filler may be, for example, 5 hours or less, or 3 hours or less, at 20°C. The curing time refers to the final setting time of the cavity filler. Furthermore, the curing time can be appropriately adjusted depending on the temperature and humidity of the construction site, the composition of the cavity filler, etc.

[0088] Examples of the aforementioned pumps include squeeze pumps, piston pumps, and diaphragm pumps.

[0089] Examples of the aforementioned construction sites include road surfaces; tunnels constructed using sheet pile methods; and various locations where backfilling with soil, sand, etc., is not possible.

[0090] The cavity filling method according to the present invention allows the above-mentioned cavity filling material to be filled into the cavity, thereby suppressing leakage from gaps while maintaining sufficient fluidity of the cavity filling material. This enables construction while suppressing leakage from gaps and maintaining sufficient fluidity of the cavity filling material.

[0091] It should be noted that the cavity filler composition, cavity filler, method for manufacturing the cavity filler, and cavity filling method according to the present invention are not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the present invention.

[0092] The present invention includes the following embodiments. [1] comprising dried sludge powder, blast furnace slag powder, and bentonite, The swelling capacity of the bentonite is 13.0 mL / 2 g or more. The content of the dried sludge powder is 20% by mass or more and 85% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder. The content of the blast furnace slag powder is 15% by mass or more and 80% by mass or less, relative to the total content of the dried sludge powder and the blast furnace slag powder. A cavity filler composition wherein the bentonite content is greater than 40% by mass and less than or equal to 60% by mass of the total content of the dried sludge powder and the blast furnace slag powder. [2] The Blaine specific surface area of ​​the dry sludge powder is 10,000 cm² 2 The cavity filler composition described in [1], wherein the amount is 1 / g or more. [3] The Blaine specific surface area of ​​the blast furnace slag powder is 3,500 cm². 2 A cavity filler composition according to [1] or [2], wherein the amount is 1 / g or more. A cavity filler composition described in any one of items [4][1] to [3], and water, A cavity filler having a water-to-powder ratio of 200% to 250%. A method for producing the cavity filler described in [5] and [4], A method for producing a cavity filler, comprising the step of kneading dried sludge powder, blast furnace slag powder, bentonite, and water. A cavity filling method comprising filling the cavity portion with the cavity filling material described in [6] and [4]. [Examples]

[0093] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments.

[0094] (Preparation of cavity filling material) The cavity fillers for each example and comparative example were prepared according to the following method. First, each powder component (dried sludge powder (STC), blast furnace slag powder (BSF), and bentonite (BNT)) was mixed according to the formulations shown in Table 1 to obtain a cavity filler composition. Next, the cavity filler composition and water (W) were kneaded at the water-to-powder ratio (W / C) shown in Table 1 to obtain the cavity fillers for each example and comparative example. The kneading of the cavity filler composition and water was performed using a hand mixer (Makita "UT2204", blade shape: crown type, blade material: stainless steel, blade diameter: 100 mm) under the conditions of a kneading time of 3 minutes and a rotation speed of 550 rpm.

[0095] The physical properties of the aforementioned dried sludge powder are as follows: ·Density: 2.6g / cm 3 • Brain specific surface area: 11,390 cm² 2 / g ·Particle size (d10): 5.0μm ·Particle size (d50): 20.5μm ·Particle size (d90): 73.4μm ·d10 / d50:0.243 ·d50 / d90:0.280 • Mass ratio passing through a sieve with a mesh size of 20 μm: 49% • Mass ratio passing through a sieve with a mesh size of 10 μm: 29% ·Mass reduction rate W1 (400-600℃): 2.9% by mass ·Mass reduction rate W2 (600-800℃): 9.0% by mass

[0096] The density of the dried sludge powder was measured according to the method described in JIS R 5201:2015 "Physical Testing Methods for Cement, 7. Density Test". The Blaine specific surface area of ​​the dried sludge powder was measured according to the method described in JIS R 5201:2015 "Physical Testing Methods for Cement, 8. Fineness Test, 8.1 Specific Surface Area Test". The particle sizes (d10, d50, and d90) of the dried sludge powder were measured using a laser diffraction particle size distribution analyzer (Microtrac-Bell MT3000). The mass loss rates W1 and W2 were determined from the thermogravimetric values ​​obtained by measuring the thermogravimetric ratio under a nitrogen atmosphere at a heating rate of 10.0°C / min using a differential thermal-thermogravimetric analyzer (Rigaku Corporation TG-8120).

[0097] The physical properties of the blast furnace slag powder are as follows: ·Density: 2.9g / cm 3 • Brain specific surface area: 4,700 cm² 2 / g

[0098] The density and Blaine specific surface area of ​​the blast furnace slag powder were measured using the same method as for the dried sludge powder.

[0099] The product name and physical properties of the bentonite are as shown in Table 2. The swelling force values ​​in Table 2 were determined based on the swelling test method of the Japan Bentonite Industry Association Standard Test Method (JBAS-104-77). The particle size (d10 and d50) of the bentonite in Table 2 was measured using the same method as for the dried sludge powder.

[0100] [Table 1]

[0101] [Table 2]

[0102] (Measurement of cylinder flow value) The cylinder flow values ​​of the cavity filler materials in each example and comparative example were measured in accordance with the flow test described in NEXCO Test Method 313. A cylinder flow value of 140 mm or more indicates that the cavity filler material has sufficient fluidity to fill the gaps under its own weight. The measurement results are shown in Table 3.

[0103] (Measurement of uniaxial compressive strength) The unconfined compressive strength of the cavity filling material in each example and comparative example at 7 and 28 days of age was measured in accordance with the unconfined compressive testing method for soil described in JIS A 1216. The measurement results are shown in Table 3.

[0104] (Measurement of breeding rate) The bleeding rate of the cavity filling material in each example and comparative example was measured in accordance with the Japan Society of Civil Engineers standard for testing the bleeding rate and expansion rate of PC grout (polyethylene bag method). The measurement results are shown in Table 3.

[0105] (Non-leakage test) The non-leakage tests of the cavity filling material for each example and comparative example were conducted using the following method, with reference to the method described in "Design and Construction Guidelines for Backfill Cavity Injection Work in Sheet Pile Tunnels, October 2006, East Nippon Expressway Co., Ltd., Central Nippon Expressway Co., Ltd., West Nippon Expressway Co., Ltd., 4. Construction, 4.8 Test Method, 3.2 Non-Leakage Test (page 32)".

[0106] Figure 1 is a schematic diagram of the test apparatus used for the non-leakage test in the embodiment. Specifically, a test apparatus as shown in Figure 1 was first constructed using a wooden frame, wooden boards, and acrylic plates. As shown in Figure 1, the test apparatus has two gaps (each gap 30 mm deep) that extend along the longitudinal direction and have open lower ends on the bottom surface of the container part of the test apparatus, with the gap between one gap being 5 mm and the gap between the other gap being 10 mm.

[0107] Next, the cavity filler materials for each example and each comparative example were poured into the container section of the test apparatus from above at a flow rate of 2 L / min, and the pouring was stopped when the material reached a height of 50 mm from the bottom surface of the container section.

[0108] After the pouring of the cavity filler was completed, the length between the water level of the cavity filler that had entered each gap and the upper end of the gap (leakage length) was determined when the water level reached a height of 50 mm from the bottom of the container section of the test apparatus. The results are shown in Table 3. In Table 3, ">30" means that the cavity filler that entered the gap did not remain inside the gap but leaked out from the opening at the lower end of the gap.

[0109] [Table 3]

[0110] As can be seen from Table 3, the cavity filler materials of each embodiment have a cylinder flow value of 140 mm or more and exhibit sufficient fluidity to penetrate gaps of 10 mm and 5 mm, yet the leakage length in all of these gaps is shorter than that of the cavity filler materials of each comparative example. Therefore, a cavity filler material that satisfies all the requirements of the present invention can suppress leakage from gaps while maintaining sufficient fluidity.

[0111] Furthermore, since the cavity filler materials in each embodiment have a cylinder flow value of 140 mm or more, they can easily enter both 10 mm and 5 mm gaps under their own weight. On the other hand, although the cavity filler material of Comparative Example 3 can suppress leakage from 10 mm and 5 mm gaps, its cylinder flow value is less than 140 mm, making it difficult for it to enter these gaps under its own weight.

[0112] Furthermore, a cavity filler composition that satisfies all the requirements of the present invention can provide a cavity filler that can suppress leakage from gaps while maintaining sufficient fluidity.

Claims

1. It contains dried sludge powder, blast furnace slag powder, and bentonite. The swelling capacity of the bentonite is 13.0 mL / 2 g or more. The content of the dried sludge powder is 20% by mass or more and 85% by mass or less of the total content of the dried sludge powder and the blast furnace slag powder. The amount of blast furnace slag powder is 15% by mass or more and 80% by mass or less, relative to the total amount of the dried sludge powder and the blast furnace slag powder. A cavity filler composition wherein the bentonite content is greater than 40% by mass and less than or equal to 60% by mass of the total content of the dried sludge powder and the blast furnace slag powder.

2. The Blaine specific surface area of ​​the aforementioned dried sludge powder is 10,000 cm². ２ The cavity filler composition according to claim 1, wherein the amount is 1 / g or more.

3. The Blaine specific surface area of ​​the blast furnace slag powder is 3,500 cm². ２ The cavity filler composition according to claim 1, wherein the amount is 1 / g or more.

4. A cavity filler composition according to any one of claims 1 to 3, and water, A cavity filler having a water-to-powder ratio of 200% to 250%.

5. A method for producing the cavity filler described in claim 4, A method for producing a cavity filler, comprising the step of kneading dried sludge powder, blast furnace slag powder, bentonite, and water.

6. A cavity filling method comprising filling a cavity portion with the cavity filling material described in claim 4.

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