Manufacturing method of cement-containing granule

Abstract

To provide a manufacturing method of cement-containing granules capable of manufacturing safely granules desirably granulated by effectively using a cement-containing composition such as concrete.SOLUTION: A manufacturing method of cement-containing granules provides cement-containing granules by: putting in a cement-containing composition containing cement and water into an agitation device having a vessel and an agitation blade that rotates in the vessel and performs rotary motion relatively to the vessel; rotating the blade after putting in water-absorbing resin but no hardening accelerator into the agitation device; and agitating the cement-containing composition and the water-absorbing resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a cement-containing granulated material. [Background technology]

[0002] Cement-containing compositions containing cement and water are further classified into concrete (cement, coarse aggregate, fine aggregate, water), mortar (cement, fine aggregate, water), and cement slurry or cement paste (cement, water) depending on the materials to be mixed. Admixtures or admixtures may also be mixed into these cement-containing compositions.

[0003] Cement-containing compositions are used in a variety of locations, such as construction sites, depending on the application. However, for example, unused concrete (so-called leftover concrete or returned concrete) is discarded, even though it has the same quality as fresh ready mixed concrete (so-called ready mixed concrete) and is unused. Also, dehydrated cake discharged from muddy water treatment facilities at ready mixed concrete manufacturing plants is discarded, even though it is made up of cement and fine aggregate and has the same components as concrete. Therefore, reusing these waste materials as concrete materials will not only reduce the amount of virgin materials used, which will lower the environmental impact, but will also contribute to reducing waste.

[0004] Patent Document 1 describes a technology in which concrete to be discarded (residual concrete, returned concrete) is mixed with solids that have settled and been classified during the cleaning of ready-mix concrete handling equipment, a cement quick-setting accelerator, and a highly water-absorbent polymer, and hardened into granules. Patent Document 1 also describes that the quick-setting accelerator is also called a hardening accelerator. Patent Document 2 describes a technique of adding a powdered or granular water-absorbent polymer sealed in a packaging material made of water-soluble paper in the form of a bag to residual concrete. [Prior art documents] [Patent documents]

[0005] [Patent Document 11] JP 2017-149611 A [Patent Document 22] Utility Model Registration No. 3147832 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the technology of Patent Document 1, in order to granulate the ready-mix concrete to be discarded, equipment is required for settling and classifying the wash water used to wash the equipment. In addition, in Patent Document 1, a hardening accelerator (quick-setting accelerator) and a highly water-absorbent polymer are added to fresh concrete, and the concrete is then mixed with a hydraulic shovel, which may result in insufficient mixing and may make it difficult to obtain homogeneous granulated material. Furthermore, Patent Document 1 describes that an ionic water-absorbent polymer or a neutral water-absorbent polymer may be used as the water-absorbent polymer, but does not describe the amount to be added. In Patent Document 1, 1 to 5 kg of hardening accelerator (rapid setting accelerator) is applied to 1 m of the target object. 3 However, the calcium aluminate given as an example has a high quick-setting tendency, and if it adheres to a hydraulic excavator, concrete and other materials become difficult to remove. Sodium aluminate is designated as a hazardous substance and is dangerous to handle. Furthermore, when a hardening accelerator (quick-setting accelerator) (such as sodium aluminate) is used, cement and other materials harden in a short time, so molding is required in a short time, making it difficult to produce granulated material of uniform quality.

[0007] According to the technology of Patent Document 2, when a water-absorbing polymer is enclosed in a water-soluble bag and poured into the remaining concrete, it is difficult to disperse the water-absorbing polymer evenly throughout the remaining concrete, and a large amount of water-absorbing polymer ends up being poured into a part of the moisture in the remaining concrete into which the water-soluble bag was poured. The water-absorbing polymer swells when it absorbs water, but when a large amount of water-absorbing polymer competes for a small amount of water, the particles of the multiple water-absorbing polymers themselves form large rubber-like lumps, making it difficult to mix evenly throughout the remaining concrete even when stirred. In addition, in Patent Document 2, the residual concrete and the water-absorbent polymer are mixed by an agitator vehicle (gravity mixer), which also results in insufficient mixing of the residual concrete and the water-absorbent polymer. In addition, the drum of the agitator vehicle has only an opening at the top where the inlet and outlet are the same, so when new concrete is produced, there is a risk of contamination with chemicals used in the previous treatment. In addition, the properties of the residual concrete are not constant because it is waste and the concrete mix is ​​not uniform but is changed according to the target strength and fluidity. Adding the water-absorbent polymer in water-soluble bags makes it difficult to adjust the excess or deficiency of the water-absorbent polymer, and there is a problem that the quality of the treated product obtained is not constant.

[0008] An object of the present invention is to provide a method for producing a cement-containing granulated material, which can effectively utilize a cement-containing composition such as concrete and safely produce a well-granulated material. [Means for solving the problem]

[0009] The present invention provides the following [1] to [9]. [1] A method for producing a cement-containing granulated material, comprising: placing a cement-containing composition containing cement and water in a container and an agitator having an agitator blade that rotates in the container and rotates relative to the container; further placing a water-absorbent resin in the agitator but not adding a hardening accelerator (quick-setting accelerator); and rotating the agitator blade to agitate the cement-containing composition and the water-absorbent resin to obtain a cement-containing granulated material. [2] The method for producing a cement-containing granulated material according to the above [1], wherein the cement-containing composition is one or more selected from the group consisting of concrete, mortar, and cement slurry. [3] The method for producing cement-containing granules described in [2] above, wherein the concrete is a dehydrated cake discharged from a concrete manufacturing plant or unused leftover concrete. [4] The method for producing a cement-containing granulated material according to any one of the above [1] to [3], wherein the water-absorbing resin is placed in the stirring device as it is without being placed in a package. [5] The method for producing a cement-containing granulated material according to any one of [1] to [4] above, wherein the amount of the water-absorbing resin added is 0.3 parts by mass or more per 100 parts by mass of the solid content of the cement-containing composition. [6] The method for producing a cement-containing granulated material according to any one of the above [1] to [5], wherein the mixing device is a forced twin-shaft mixer or a pan mixer. [7] The method for producing a cement-containing granulated material according to any one of the above [1] to [6], wherein the cement-containing granulated material has a particle size of 30 mm or less. [8] The method for producing a cement-containing granulated material according to any one of the above [1] to [7], wherein the water-absorbent resin is a poly(meth)acrylic acid-based polymer. [9] The method for producing a cement-containing granulated material according to any one of the above [1] to [8], wherein the cement-containing composition is placed in the stirring device, the stirring blade is rotated, and then the water-absorbing resin is added. Effect of the Invention

[0010] According to the present invention, a method for producing a cement-containing granulated material can be provided, which can effectively utilize a cement-containing composition such as concrete to safely produce a well-granulated material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, one embodiment of the present invention will be described in detail. In this specification, the term "solid content" refers to components excluding the solvent (water, etc.), and the term "solid content concentration" refers to the concentration of components excluding the solvent (water, etc.) from a composition, etc. In the present invention, "(meth)acrylic" means acrylic or methacrylic.

[0012] The method for producing a cement-containing granulated material according to the present invention is a method for producing a cement-containing granulated material, which comprises: placing a cement-containing composition containing cement and water in a container and an agitator having an agitator blade that rotates in the container and rotates relative to the container; further placing a water-absorbent resin in the agitator but not adding a hardening accelerator (quick-setting accelerator); rotating the agitator blade to agitate the cement-containing composition and the water-absorbent resin, thereby obtaining a cement-containing granulated material (hereinafter sometimes simply referred to as a "granulated material").

[0013] According to the present invention, a cement-containing granulated product can be obtained by effectively utilizing a cement-containing composition such as concrete. In addition, according to the present invention, since a hardening accelerator (quick-setting accelerator) is not used, a granulated product can be safely produced and the cost of chemicals can be reduced. Furthermore, according to the present invention, since the above-mentioned stirring device is used, a well-granulated product can be produced. In addition, since the rotating drum of the agitator car has only an opening at the top, which is the same as the inlet and outlet, washing the drum after the production of the granulated product is time-consuming and difficult, and a large amount of washing water is required, resulting in the discharge of a large amount of dirty wastewater. In contrast, the planetary mixer has a large open upper part and can discharge wastewater from the lower part, making it easy to wash and efficient to wash, and it is possible to reduce the amount of washing wastewater.

[0014] [Cement-containing composition] The cement-containing composition is preferably one or more selected from the group consisting of concrete, mortar, and cement slurry obtained by separating turbid water containing cement through sedimentation, dehydrating the dehydrated cake, and stirring the dehydrated cake to make a slurry. The cement-containing composition may or may not contain aggregate. In this embodiment, aggregate, fine aggregate, coarse aggregate, concrete, and mortar have the following meanings. · Aggregate: Material that accounts for 50-80% (for example, about 70%) of the volume of concrete. Examples include river sand, mountain sand, etc. Fine aggregate: 85% or more of the total aggregate has a particle size of 5mm or less. Coarse aggregate: 85% or more of the total aggregate has a particle size of 5mm or more. · Concrete: Contains cement, fine aggregate, coarse aggregate, water, admixtures and additives. · Mortar: Contains cement, fine aggregate, and water.

[0015] The cement-containing composition is preferably not a virgin material but a cement-containing composition that has not been used at a construction site or the like, or that has been discharged from a turbid water treatment facility at a concrete manufacturing plant, etc. This contributes to reducing industrial waste. The cement-containing composition is preferably at least one selected from the group consisting of unused concrete (so-called leftover concrete or returned concrete) and dewatered cake discharged from turbid water treatment facilities in concrete manufacturing plants and the like. The concrete may be, for example, dewatered cake discharged from a concrete manufacturing plant or may be leftover unused concrete.

[0016] [Water absorbent resin] Water-absorbent resins are defined in JIS K7223 (1996) and JIS K7224 (1996) as "resins that highly absorb water and swell, are hydrophilic substances with a cross-linked structure that absorb water when they come into contact with water, and once they have absorbed water, they are less likely to release water even when pressure is applied." In other words, they are resins that absorb a large amount of water and have excellent water retention.

[0017] The type of water-absorbing resin may be either synthetic resin-based or natural product-based, and is not particularly limited, but is more preferably synthetic resin-based. Synthetic resin-based resins have the advantages of being easy to manufacture homogeneous granules because of their high water absorption capacity and constant composition, and being less likely to scatter during stirring because of their constant particle size compared to natural water-absorbing bodies, suppressing the generation of odor due to decay, and suppressing the formation of voids inside the treated residual concrete due to volume change.

[0018] Examples of types of water-absorbing resins include cross-linked products of poly(meth)acrylic acid polymers, cross-linked products of polyalkyleneimines, cross-linked products of polyoxyalkylenes, cross-linked products of polymaleic acids, and cross-linked products of copolymers containing any of the monomers constituting these. Examples of poly(meth)acrylic acid polymers include poly(meth)acrylic acid, poly(meth)acrylates, poly(meth)acrylic acid esters, poly(meth)acrylamides, and copolymers containing any of the monomers constituting these. Examples of poly(meth)acrylic acid polymers include poly(meth)acrylic acid, poly(meth)acrylates, poly(meth)acrylic acid esters, poly(meth)acrylamides, polyalkyleneimines, polyoxyalkylenes, polymaleic acids, and copolymers containing any of the monomers constituting these.

[0019] Examples of monomers constituting the poly(meth)acrylate include sodium (meth)acrylate and potassium (meth)acrylate. Examples of monomers constituting poly(meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxyethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of monomers constituting polyalkyleneimines include ethyleneimine and methylethyleneimine. Examples of monomers constituting the polyoxyalkylene include ethylene oxide and propylene oxide. Examples of other monomers constituting the copolymer include vinyl sulfonic acid, styrene sulfonic acid, N-ethyl (meth)acrylamide, and vinylpyridine.

[0020] The water-absorbing resin may be used alone or in combination of two or more. From the viewpoints of availability and high water-absorbing capacity, a crosslinked product of polyacrylic acid-sodium polyacrylate copolymer, a crosslinked product of polyacrylamide-polyacrylic acid copolymer, a crosslinked product of polyacrylic acid, or a crosslinked product of sodium polyacrylate is preferably used, and a crosslinked product of polyacrylic acid-sodium polyacrylate copolymer or a crosslinked product of polyacrylamide-polyacrylic acid copolymer is particularly preferred.

[0021] Since the water contained in the cement-containing composition is absorbed by the cement and aggregate and is not in a free state, it is difficult to determine the amount of water absorbent resin to be added based on the water. The present inventors have found that by defining the amount of the water absorbent resin to be added relative to 100 parts by mass of the solid content of the cement-containing composition within a specific range, appropriate modification is possible. That is, the amount of the water-absorbing resin added to 100 parts by mass of the solid content of the cement-containing composition is preferably 0.3 parts by mass or more. When it is 0.3 parts by mass or more, the water-absorbing effect of the water-absorbing resin is well expressed, and the granulated material can be easily produced. In addition, there is no particular limit to the upper limit of the amount added, but from the viewpoint of cost reduction, it is preferably 3.0 parts by mass or less. In addition, when it is 3.0 parts by mass or less, the ratio of the water-absorbing resin to the moisture is low, so that it is easy to mix with concrete, and the formation of lumps of the water-absorbing resin in parts is prevented, and uniform dispersion is possible. In addition, when it is 3.0 parts by mass or less, costs can be reduced. From this viewpoint, the amount of the water-absorbent resin added per 100 parts by mass of the solid content of the cement-containing composition is more preferably 0.3 to 3.0 parts by mass, and further preferably 0.5 to 2.0 parts by mass.

[0022] It is preferable to put the water-absorbing resin directly into the stirring device without storing it in a package, which allows the water-absorbing resin to be stirred quickly and allows the necessary amount to be added by adjusting it.

[0023] [Mixing device] The stirring device has a container and a stirring blade that rotates within the container and rotates relative to the container. Here, the agitator wheel has an agitating blade fixed to the inner wall of the drum, and the agitating blade also rotates as the drum rotates. However, since the agitating blade does not rotate relative to the drum (container), it is not included in the agitation device of the present invention. The mixing device of the present invention is different from the agitator wheel (gravity type) in that the mixing blade rotates relative to the container to perform forced mixing, so that the water absorbent resin can be mixed quickly and homogeneously into the cement-containing composition. This prevents a large amount of water absorbent resin from being unevenly distributed, and produces a granulated material that is well granulated throughout the device, and prevents the generation of granulated material due to uneven distribution of the water absorbent resin.

[0024] In addition, by mixing the water-absorbing resin into the cement-containing composition quickly and uniformly, it is possible to prevent a situation in which a large amount of undispersed water-absorbing resin absorbs water in one place, becomes lumpy, and loses its water-absorbing ability, so that the amount of the water-absorbing resin added per 100 parts by mass of the solid content of the cement-containing composition can be increased. By uniformly adding a large amount of water-absorbing resin in this way, even when the residual concrete or cement paste contains a lot of moisture and a large amount of water-absorbing resin is required, a granulated product can be produced satisfactorily.

[0025] The stirring device may be of either a continuous type or a batch type. As the continuous mixing device, from the viewpoint of rapidly and homogeneously mixing the water-absorbent resin with the cement-containing composition, a forced twin-screw mixer or a paddle-type mixer is preferable, and a forced twin-screw mixer is more preferable. As the batch type mixing device, from the viewpoint of rapidly and homogeneously mixing the water absorbent resin into the cement-containing composition, a pan type mixer or a forced twin-shaft mixer is preferable, and a pan type mixer is more preferable. As the pan type mixer, a planetary type mixer is preferable.

[0026] The "gearbox rotation speed (rotation) / blade rotation speed" (hereinafter sometimes referred to as the "rotation / revolution ratio") of the planetary mixer is preferably 0.1 to 1.0, and more preferably 0.3 to 0.5.

[0027] [Cure accelerator] When the cement-containing composition is put into the mixing device and the water-absorbent resin is further put into the mixing device, no hardening accelerator (quick-setting accelerator) is put in. Since the hardening accelerator (quick-setting accelerator) is not added into the mixing device in this way, the granulated material can be safely produced and the cost of chemicals can be reduced. From the viewpoint of safely producing granulated materials, no hardening accelerator (quick-setting accelerator) is added to the cement-containing composition even before the cement-containing composition is placed in the mixing device. In addition, as long as the production of granules can be carried out safely, the cement-containing composition that has not been used at a construction site or that has been discharged from a turbid water treatment facility may already contain a hardening accelerator (quick-setting accelerator). However, it is preferable to subject a cement-containing composition that does not contain a hardening accelerator (quick-setting accelerator) to the method for producing cement-containing granules according to the present invention. Here, the hardening accelerator means an admixture used to accelerate the hydration of cement and increase the strength development at an early age, as specified in JIS A0203:2014. The hardening accelerator is typically a material capable of forming calcium aluminate hydrate and accelerating the hydration reaction of cement. Examples of hardening accelerators include calcium aluminate, aluminum sulfate, sodium aluminate, calcium aluminate, and the like.

[0028] [Cement-containing granulated material] The particle size of the cement-containing granulated material is preferably 30 mm or less. If the particle size is 30 mm or less, the aggregate is prevented from becoming brittle, is less likely to crack, and is more likely to become dense, resulting in high hardness. From this viewpoint, the particle size of the cement-containing granulated material is more preferably 10 mm or less. The particle size of the cement-containing granules can be measured using a vernier caliper. The cement-containing granules preferably have a spherical shape from the viewpoint of the fluidity of the mixture when reused as aggregate. The shape of the cement-containing granules can be confirmed by visual inspection.

[0029] [Example of a suitable manufacturing method] It is preferable to put the cement-containing composition into the stirring device, rotate the stirring blade, and then put the water-absorbing resin in. This allows the water-absorbing resin and the cement-containing composition to be stirred quickly. The stirring time is preferably 30 seconds or more, more preferably 1 minute or more, and further preferably 2 minutes or more, from the viewpoint of quickly and homogeneously mixing the water-absorbent resin into the cement-containing composition. EXAMPLES

[0030] Next, specific examples of the present invention will be described, but the present invention is not limited to these examples.

[0031] [Raw materials, etc.] The following were used as raw materials: (1) Water absorbent resin 1 Polyacrylate-based water-absorbent resin Average particle size: 350μm Appearance: White granules

[0032] (2) Flocculant 1 Polyacrylamide-polyacrylate copolymer "Kurisat C-333L" manufactured by Kurita Water Industries Ltd. Appearance: white milky

[0033] (3) Cement Ordinary Portland Cement (4) Sand Toyoura Silica Sand

[0034] [Examples 1 to 4 and Comparative Examples 1 to 3] 51 g of water, 29 g of cement, and 200 g of sand were placed in a 500 mL beaker and thoroughly stirred with a spatula to prepare a cement-containing composition 1 (cement slurry 1). Additives of the types and amounts shown in Table 1 were added to the cement-containing composition 1, and the mixture was stirred with a spatula for 1 minute to obtain an evaluation object. The spatula simulates a stirring blade that rotates within the container and rotates relative to the container. In other words, the beaker and the spatula simulate a container and a stirring device having a stirring blade that rotates within the container and rotates relative to the container. The particle size of the obtained evaluation objects was measured by the sieve method and judged based on the following criteria. The results are shown in Table 1. ⊚: The evaluation object was a granulated product with a particle size of less than 10 mm. ◯: The evaluation object was a granulated product with a particle size of 10 mm or more and 30 mm or less. △: The evaluation object was a granulated product with a particle size of more than 30 mm. ×: The evaluation object was a slurry or spinnable granule.

[0035] [Comparative Example 4] An agitator simulation device was obtained by bonding two pieces of wood (5 mm square, 150 mm long) to the inside of a 500 mL beaker at two points. A cement-containing composition 1 (cement slurry 1) obtained in the same manner as in Example 1 was immediately placed in the agitator simulator. With the beaker of the agitator simulator tilted at 45°, the same types of additives as in Example 1 were added to the cement-containing composition 1 in the same amounts, and the beaker was rotated for 1 minute to obtain an evaluation object. The beaker was rotated at a speed of 3 rpm around a line passing through the center of the bottom surface (circular) of the beaker and perpendicular to the bottom surface as the axis of rotation.

[0036] [Examples 5 to 7 and Comparative Example 5] 260 g of water, 114 g of cement, and 381 g of sand were placed in a 500 mL beaker and thoroughly stirred with a spatula to prepare a cement-containing composition 2 (cement slurry 2). The cement-containing composition 2 was added with additives of the types and amounts shown in Table 2, and stirred with a spatula for 1 minute to obtain an evaluation object. The particle size of the obtained evaluation object was measured by the sieve method and evaluated based on the same criteria as in Example 1. The results are shown in Table 2.

[0037] [Table 1]

[0038] [Table 2]

[0039] [Evaluation Results] In Examples 1 to 4 and Examples 5 to 7, a water-absorbing resin was added as an additive to the cement-containing composition, and the composition was stirred using a stirring device having a container (beaker) and a member (spatula) equivalent to a stirring blade that rotates within the container (beaker) and rotates relative to the container (beaker), thereby obtaining a granulated product. On the other hand, in Comparative Examples 1 to 3 and 5, a flocculant was added as an additive to the cement-containing composition, which resulted in the evaluation objects having spinnability. In Comparative Example 4, since the stirring was performed using a stirring device simulating an agitator, the cement-containing composition and the water-absorbent resin were not sufficiently stirred, and the water-absorbent resin on the cement-containing composition absorbed only a portion of the water and became lumpy, so that no granulation action occurred.

[0040] [Example 8] The raw materials shown in Table 3 below were mixed in the amounts shown in Table 3 below to obtain a cement-containing composition. 20 kg of the cement-containing composition was put into a pan-type mixer having the specifications shown in Table 4, and then water-absorbent resin 1 was added as a chemical agent in an amount of 0.4 parts by mass relative to 100 parts by mass of the solid content of the cement-containing composition. Then, the mixer was operated at 60 Hz for 2 minutes. The particle size of the obtained target particles was measured with a vernier caliper, and the arithmetic average value of the five granulated particles was taken as the particle size, and the particle size was judged based on the following criteria. The results are shown in Table 5. ⊚: The evaluation object was a granulated product with a particle size of less than 10 mm. ◯: The evaluation object was a granulated product with a particle size of 10 mm or more and 30 mm or less. ×: The evaluation object was not granulated or was in the form of coarse lumps.

[0041] [Examples 9 to 10 and Comparative Examples 6 to 8] The target substance was obtained in the same manner as in Example 8, except that the type of mixer shown in Table 4 was used and the amount of the drug added was as shown in Table 5. The obtained object was evaluated in the same manner as in Example 8. The results are shown in Table 5.

[0042] [Table 3]

[0043] [Table 4]

[0044] [Table 5]

[0045] [Evaluation Results] In Examples 8 to 10, a water-absorbing resin was added as an additive to the cement-containing composition, and the mixture was stirred using a stirring device having a container and a member equivalent to a stirring blade that rotates in the container and rotates relative to the container, thereby obtaining a granulated product. On the other hand, in Comparative Examples 6 to 8, since no water-absorbent resin was added as an additive to the cement-containing composition, granules could not be obtained.

[0046] [Reference examples 1~3] 10 kg of sludge cake discharged from a ready-mix concrete factory was charged into a mixer shown in Table 6 below, and water was added to adjust the moisture content to 40 mass %. The mixer was then operated at 60 Hz for 10 minutes. The obtained objects were visually inspected and judged based on the following criteria, and the results are shown in Table 6. ◯: The slurry was thawed and uniform. △: The slurry was thawed but was uneven. ×: The mud did not dissolve.

[0047] [Table 6]

[0048] [Evaluation Results] As shown in Table 6, the planetary mixer had the best mud-removal ability, followed by the twin-shaft mixer and the pan-type mixer.

Claims

1. A method for producing a cement-containing granulated material, comprising: placing a cement-containing composition containing cement and water in a container and an agitator having an agitator blade that rotates in the container and rotates relative to the container; further placing a water-absorbent resin in the agitator but not a hardening accelerator; and rotating the agitator blade to agitate the cement-containing composition and the water-absorbent resin to obtain a cement-containing granulated material.

2. The method for producing a cement-containing granulated material according to claim 1, wherein the cement-containing composition is one or more selected from the group consisting of concrete, mortar, and cement slurry.

3. The method for producing cement-containing granules according to claim 2, wherein the concrete is a dehydrated cake discharged from a concrete manufacturing plant or unused remaining concrete.

4. The method for producing a cement-containing granulated material according to any one of claims 1 to 3, wherein the water-absorbing resin is placed in the stirring device as it is without being placed in a package.

5. The method for producing a cement-containing granulated material according to any one of claims 1 to 3, wherein the amount of the water absorbent resin added is 0.3 parts by mass or more per 100 parts by mass of solid content of the cement-containing composition.

6. The method for producing a cement-containing granulated material according to any one of claims 1 to 3, wherein the mixing device is a forced twin-shaft mixer or a pan mixer.

7. The method for producing cement-containing granules according to any one of claims 1 to 3, wherein the cement-containing granules have a particle size of 30 mm or less.

8. The method for producing a cement-containing granulated material according to any one of claims 1 to 3, wherein the water-absorbent resin is a poly(meth)acrylic acid-based polymer.

9. The method for producing a cement-containing granulated material according to any one of claims 1 to 3, wherein the cement-containing composition is placed in the stirring device, and the stirring blade is rotated, and then the water-absorbing resin is added.

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