Flowable backfilling material and manufacturing method of flowable backfilling material

Abstract

To provide a flowable backfilling material that is easy to control in quality and has high manufacturing efficiency and environmental friendliness, and a manufacturing method of the flowable backfilling material.SOLUTION: A flowable backfilling material 1 of the present invention is made by kneading a binder 10, aggregate 20, and water 30. The binder 10 contains an active filler 11. The aggregate 20 is made of granulated fine aggregate 21 or sludge powder 22 derived from the granulated fine aggregate 21 and sludge cake A, and has a slump flow value of 200 mm or more and an uniaxial compressive strength (28 days) of 0.3 N / mm2 or more. In a manufacturing method of the flowable backfilling material of the present invention, the binder 10, aggregate 20, and water 30 are kneaded to manufacture the flowable backfilling material 1. The binder 10 contains the active filler 11. The aggregate 20 is made of the granulated fine aggregate 21 or the sludge powder 22 derived from the granulated fine aggregate 21 and the sludge cake A. The materials are mixed so that the slump flow value is 200 mm or more and the uniaxial compressive strength (28 days) is 0.3 N / mm2 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fluid backfill material and a method for manufacturing the fluid backfill material, and more particularly to a fluid backfill material and a method for manufacturing the fluid backfill material that are easy to manage quality and have high manufacturing efficiency and environmental performance.

Background Art

[0002] As a backfill material for burying underground structures such as underpasses and utility tunnels, and underground buried objects such as electricity, water supply, gas, and communication, a fluid backfill material mainly composed of construction-generated soil is known (Patent Document 1). The conventional fluid backfill material is composed of construction-generated soil, adjusted muddy water, and a cement-based solidifying material, and is manufactured by, for example, the following method. Clear water is added to the construction-generated soil in the sludge pit and stirred to generate adjusted muddy water (sludge separation process). Simultaneously with the sludge separation operation, foreign matters such as gravel, clay, wood chips, and wire in the adjusted muddy water are sieved and removed (removal process). The adjusted muddy water from which gravel and the like have been removed is put into a mixer, and the construction-generated soil and the cement-based solidifying material are mixed and stirred to produce a fluidized treatment soil (stirring process). The fluidized treatment soil is manufactured by applying a formulation design that can ensure fluidity capable of filling the voids without gaps and strength and density consistent with the design purpose in relation to the type and state of the construction-generated soil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The following problems exist in the prior art. <1> Problem of quality control The quality of construction-generated soil varies depending on the procurement source and the procurement time. Therefore, it is necessary to formulate the adjusted slurry and binder for each type of construction-generated soil, making quality control difficult. <2>Problem of manufacturing efficiency For the production of the adjusted slurry, a sludge pit is required to input the construction-generated soil, add clear water, and a sludge-disaggregation process of stirring with heavy machinery is necessary. Also, if foreign substances such as wood chips and wire are mixed in the construction-generated soil, there is a risk of clogging the pipes during pumping and damaging the equipment. Therefore, a process of detecting and removing foreign substances in the construction-generated soil before stirring the materials is necessary. For this reason, manufacturing takes time and effort, and the manufacturing efficiency is poor. <3>Problem of transportation cost It is necessary to transport the construction-generated soil from external recycling facilities. Since the recycling facilities require a large site for storage, the number of installations is limited, and as a result, the transportation distance is often relatively long. For this reason, the transportation cost increases. <4>Problem of environmental load Carbon dioxide emitted during the production of cement-based solidifying materials and a large amount of exhaust gas accompanying the transportation of construction-generated soil are factors that impose a load on the environment.

[0005] An object of the present invention is to provide a fluid backfill material and a method for manufacturing the fluid backfill material for solving the above problems.

Means for solving the problems

[0006] The fluid backfill material of the present invention is a fluid backfill material obtained by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate, the slump flow value is 200 mm or more, and the uniaxial compressive strength (28 days) is 0.3 N / mm 2 or more, which is characterized by the above.

[0007] The fluid backfill material of the present invention is a fluid backfill material obtained by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate and sludge powder derived from sludge cake, the slump flow value is 200 mm or more, and the uniaxial compressive strength (28 days) is 0.3 N / mm2 It is characterized by the above.

[0008] In the case of the fluidity backfill material of the present invention, in the aggregate, the blending ratio of sludge powder may be 30% or less by volume ratio.

[0009] The fluidity backfill material of the present invention may have a uniaxial compressive strength (at 28 days) of 1.0 N / mm 2 or less.

[0010] In the case of the fluidity backfill material of the present invention, the binder may be composed of fine blast furnace slag powder.

[0011] The method for producing a fluidity backfill material of the present invention is a method for producing a fluidity backfill material by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate is composed of granulated fine aggregate, and the slump flow value is 200 mm or more and the uniaxial compressive strength (at 28 days) is 0.3 N / mm 2 and is characterized in that they are blended so as to satisfy the above conditions.

[0012] The method for producing a fluidity backfill material of the present invention is a method for producing a fluidity backfill material by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate is composed of granulated fine aggregate and sludge powder derived from sludge cake, and the slump flow value is 200 mm or more and the uniaxial compressive strength (at 28 days) is 0.3 N / mm 2 and is characterized in that they are blended so as to satisfy the above conditions.

[0013] In the case of the method for producing a fluidity backfill material of the present invention, in the aggregate, the blending ratio of sludge powder may be 30% or less by volume ratio.

[0014] The method for producing a fluidity backfill material of the present invention may have a uniaxial compressive strength (at 28 days) of 1.0 N / mm 2 or less.

Advantages of the Invention

[0015] The flowable backfilling material and the method for manufacturing the flowable backfilling material of the present invention have the above-mentioned configuration and therefore have at least one of the following effects. <1> Easy quality control Since the main material is a concrete by-product manufactured under strict quality control, it is possible to steadily produce high-quality fluid backfill material. In addition, since no adjustment mud water is used, complex mix design is not necessary, and the desired fluidity and compressive strength can be ensured simply by mixing the aggregate and controlling the unit water content. <2> High manufacturing efficiency Since there is no need for sludge deflocculation or foreign matter removal work and production can be carried out using only a batcher plant, production efficiency is high. <3> Low manufacturing costs Since material procurement is completed within the concrete plant and there is no need to bring in construction waste soil from outside, no transportation costs are incurred. In addition, while disposal of leftover concrete and sludge cake at concrete plants requires huge disposal costs, by reusing these as granulated fine aggregate or sludge powder, the cost of procuring materials is reduced, allowing for cheaper production. <4> High environmental performance By utilizing the alkaline stimulation function of granulated fine aggregate and sludge powder, active fillers such as ground granulated blast furnace slag can be used as binders, which can significantly reduce carbon dioxide emissions compared to conventional cement-based solidification materials. In addition, granulated fine aggregate and sludge powder, which have a large surface area, can adsorb carbon dioxide during storage, allowing large amounts of carbon dioxide to be stored in the filled space of underground structures and underground buried objects (CCU). [Brief description of the drawings]

[0016]

Figure 1

[0017] The flowable backfilling material and the method for producing the flowable backfilling material of the present invention will be described in detail below with reference to the drawings.

[0018] [Flowable backfill material] <1> Overall configuration (Figure 1) The fluid backfill material 1 is a type of controlled low-strength material (CLSM) used for backfilling, backfilling, and filling spaces that are difficult to work on using compaction equipment, such as underground passages, utility tunnels, and underground voids. The flowable backfilling material 1 is produced by kneading a binder 10, aggregate 20, and water 30. A specific example of the blending of the flowable backfilling material 1 will be described later. The fluid backfilling material 1 must have both fluidity that allows it to fill voids and compressive strength that allows it to support a structure after filling. From the above, the fluid backfill material 1 has a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 Ensure that the slump flow is the average value of two perpendicular diameters. In addition, it is preferable that the fluid backfill material 1 can be dug up again using heavy machinery such as a backhoe when re-excavating. Therefore, in this example, the upper limit of the uniaxial compressive strength is set to 1.0 N / mm 2 The unconfined compressive strength at 28 days was set at 0.3 N / mm 2 More than 1.0N / mm 2 The upper limit of the unconfined compressive strength is not an essential constituent requirement.

[0019] <2> Binding material The bonding material 10 is a binder for the fluidized backfill material 1 . The binder 10 includes at least an active filler 11 . The active filler 11 is a powder having latent hydraulic properties and exhibiting a hydration reaction in an alkaline environment. In this example, ground granulated blast furnace slag (BFS) is used as the active filler 11, and the binder 10 is composed only of ground granulated blast furnace slag. Ground granulated blast furnace slag is a powder made by drying and pulverizing granulated blast furnace slag, a by-product of steelmaking in a blast furnace, and hardens by reacting with an alkaline activator. However, the active filler 11 is not limited to ground granulated blast furnace slag, and for example, fly ash (FA) may be used, and the binder 10 may consist only of fly ash. Moreover, as the binder 10, blast furnace cement (type B) in which the active filler 11 is mixed with ordinary Portland cement, or the like, may be used.

[0020] <3> aggregate The aggregate 20 is the main material of the flowable backfill material 1 . The aggregate 20 includes at least granulated fine aggregate 21 . In this embodiment, a case where the aggregate 20 is made of only granulated fine aggregate 21 and a case where a part of the granulated fine aggregate 21 is replaced with sludge powder 22 will be described. When a part of the aggregate 20 is sludge powder 22, the volume ratio of the sludge powder 22 in the aggregate 20 mixture is desirably 30% or less. The flow value and material separation resistance of the fluid backfill material 1 of the present invention can be adjusted by the mixture of the granulated fine aggregate 21 and the sludge powder 22. This makes it easy to design the mixture.

[0021] <3.1> Granulated fine aggregate The granulated fine aggregate 21 is fine aggregate obtained by granulating concrete. Techniques for granulating concrete include, for example, a method in which a water-absorbent polymer or a quick-setting accelerator is added to the concrete and then mixed. In detail, while the concrete remains in the drum of the agitator vehicle, the water-absorbing polymer and quick-setting accelerator are added into the drum, and the drum is rotated to mix / agitate the water-absorbing polymer and quick-setting accelerator into the concrete. As the drum rotates, the mortar paste is layered on the surface of the aggregate in the concrete, forming granules. After the drum has rotated for a specified time, the discharge port is opened and the granulated concrete is discharged from the chute and left to dry and cure for a specified time. Alternatively, a method may be used in which sludge residue is mixed with concrete and granulated by stirring / aeration. Granulated fine aggregate 21 containing cement paste derived from concrete can be obtained by classifying the granulated concrete into particles of 5 mm or less using a vibrating sieve or trommel.

[0022] <3.1.1> Remaining concrete In this example, the concrete of the granulated fine aggregate 21 is made of residual concrete. Here, "remaining concrete" includes so-called "remaining concrete" (concrete that remains in the agitator truck after unloading at the work site) and so-called "returned concrete" (concrete that is not unloaded from the agitator truck and is returned to the ready-mix concrete plant). By producing the granulated fine aggregate 21 from residual concrete, it is possible to eliminate disposal costs and waste of resources that would otherwise be incurred in disposing of the residual concrete as industrial waste.

[0023] <3.2> Sludge powder The sludge powder 22 is a powder obtained by grinding the sludge cake A. The sludge powder 22 has an abundance of calcium hydroxide from the sludge cake A. The sludge powder 22 has both an alkaline stimulating function for the binder 10 due to calcium hydroxide and a fluidity control function for the fluid backfill material 1 due to its powder form. In mixing the fluid backfilling material 1, by partially replacing the granulated fine aggregate 21 with sludge powder 22, the fluidity and viscosity of the fluid backfilling material 1 can be easily adjusted.

[0024] <3.2.1> Sludge cake Sludge cake A is the solid content contained in the washing wastewater from the washing process of concrete manufacturing equipment. In detail, the washing wastewater is squeezed with a filter press and separated from the sludge water by solid-liquid separation to recover the cake. Techniques for recovering the sludge powder 22 from the sludge cake A include, for example, a method in which the sludge cake A is broken down using a vibrating sieve to classify it into fine sludge particles, and the sludge particles are ground in a mill or sand refiner to form a powder. The fluid backfill material 1 of the present invention utilizes sludge cake A, which was previously landfilled at a high cost of several thousand yen per ton, as the raw material for sludge powder 22, resulting in a negative cost and allowing for a significant reduction in manufacturing costs.

[0025] <4> supernatant water The supernatant water is the top layer of sludge water discharged after cleaning concrete manufacturing equipment. In this example, supernatant water is used as the water 30 for mixing the flowable backfill material 1. The supernatant water is recovered, for example, by pouring sludge water, which is a suspension, into a settling tank and allowing solids to settle. The supernatant water contains a large amount of calcium hydroxide that has dissolved from the cement adhering to the concrete manufacturing equipment, and therefore can exert an alkaline stimulating effect on the active filler 11. EXAMPLES

[0026] A production test was carried out on the flowable backfill material of the present invention. <1> Examples 1 to 3 Examples 1 to 3 are examples in which blast furnace cement B was used as the binder 10, granulated fine aggregate 21 was used as the aggregate 20, and supernatant water was used as the water 30. Examples 1 to 3 have a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 More than 1.0N / mm 2 The following was secured: <2> Example 4 Example 4 is an example in which blast furnace cement B is used as the binder 10, granulated fine aggregate 21 is used as the aggregate 20, and tap water is used as the water 30. Example 4 has a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 More than 1.0N / mm 2 The following was secured: <3> Examples 5 to 9 Examples 5 to 9 are examples in which ground granulated blast furnace slag was used as the binder 10, granulated fine aggregate 21 was used as the aggregate 20, and supernatant water was used as the water 30. Example 5 has a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2The above was achieved, but the unconfined compressive strength at 28 days was 1.194N / mm 2 It became. For this reason, in Examples 6 to 9, the unit weight of the binder 10 was adjusted to 50% and 80% of that in Example 5. As a result, Examples 6 to 9 had a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 More than 1.0N / mm 2 The following was secured: <4> Examples 10 to 13 Examples 10 to 13 are examples in which ground granulated blast furnace slag is used as the binder 10, supernatant water is used as the water 30, and the granulated fine aggregate 21 of the aggregate 20 is replaced with sludge powder 22. In Example 10, the aggregate volume ratio of the granulated fine aggregate 21 to the sludge powder 22 is 9:1 (614 L / m 3 :68L / m 3 Example 10 has a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 More than 1.0N / mm 2 The following was secured: In Example 11, the aggregate volume ratio of the granulated fine aggregate 21 to the sludge powder 22 is 7:3 (443 L / m 3 : 190L / m 3 Example 11 has a slump flow value of 200 mm or more and an unconfined compressive strength of 0.3 N / mm at 28 days. 2 More than 1.0N / mm 2 The following was secured: In Example 12, the aggregate volume ratio of the granulated fine aggregate 21 to the sludge powder 22 was 5:5 (291 L / m 3 :291L / m 3 Example 12 has a slump flow value of 200 mm or more and an unconfined compressive strength of 1.0 N / mm at 28 days. 2 The following was secured, but the unconfined compressive strength at 28 days was 0.266N / mm 2 This gives 0.3N / mm 2 It fell below . In Example 13, the aggregate 20 is composed only of sludge powder 22. Example 13 has a slump flow value of 200 mm or more and an unconfined compressive strength of 1.0 N / mm at 28 days. 2The following was secured, but the unconfined compressive strength at 28 days was 0.145N / mm 2 This gives 0.3N / mm 2 It fell below . From the above, it is desirable that the mixture of the sludge powder 22 in the aggregate 20 be approximately 30% or less in volume ratio, although this depends on other mixtures. [Explanation of symbols]

[0027] 1 Flowable backfill material 10 Binding material 11 Active Fillers 20 Aggregate 21 Granulated fine aggregate 22 Sludge Powder 30 water A Sludge Cake

Claims

1. A fluid backfill material obtained by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate, the slump flow value is 200 mm or more, The uniaxial compressive strength (at 28 days) is 0.3 N / mm ２ or more, characterized by a fluid backfill material.

2. A fluid backfill material obtained by kneading a binder, an aggregate, and water, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate and sludge powder derived from sludge cake, the slump flow value is 200 mm or more, The uniaxial compressive strength (at 28 days) is 0.3 N / mm ２ or more, characterized by a fluid backfill material.

3. The fluid backfill material according to Claim 2, wherein the blending ratio of the sludge powder in the aggregate is 30% or less by volume. The fluid backfill material according to Claim 2.

4. The uniaxial compressive strength (at 28 days) is 1.0 N / mm ２ characterized by being as follows: The fluid backfill material according to any one of Claims 1 to 3.

5. The fluid backfill material according to any one of Claims 1 to 3, wherein the binder consists of blast furnace slag fine powder. The fluid backfill material according to any one of Claims 1 to 3.

6. A method for producing a fluid backfill material, comprising kneading a binder, an aggregate, and water to produce a fluid backfill material, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate, The slump flow value is 200 mm or more and the uniaxial compressive strength (at 28 days) is 0.3 N / mm ２ or more, characterized by being formulated as such, a method for producing a fluid backfill material.

7. A method for producing a fluid backfill material, comprising kneading a binder, an aggregate, and water to produce a fluid backfill material, wherein the binder contains an active filler, the aggregate consists of granulated fine aggregate and sludge powder derived from sludge cake, The slump flow value is 200 mm or more and the uniaxial compressive strength (at 28 days) is 0.3 N / mm ２ or more, characterized by being formulated as such a method for producing a fluid backfill material.

8. The method for producing a fluid backfill material according to Claim 7, wherein the blending ratio of the sludge powder in the aggregate is 30% or less by volume. The method for producing a fluid backfill material according to Claim 7.

9. The uniaxial compressive strength (at 28 days) is 1.0 N / mm ２ characterized by being as follows The method for producing a fluid backfill material according to any one of Claims 6 to 8.

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