WO2008032467A1 - Process for treatment of residual ready mixed concrete, recycled cement, and aggregate for concrete - Google Patents

Abstract

A process for the treatment of residual ready mixed concrete which permits easy separation and recovery and can bring about a recyclable aggregate and recyclable fine powder. More specifically, a process for the treatment of residual ready mixed concrete which comprises the mixing/agitation step (3) of mixing returned ready mixed concrete and/or ready mixed concrete sludge as residual ready mixed concrete with a dry aggregate and/or dry fine powder as dry raw material under agitation to form a mixed raw material (30) through the adhesion of water contained in the residual ready mixed concrete to the dry raw material and the absorption thereof by the dry raw material and the classification step (4) of classifying the mixed raw material (30) into an aggregate and fine powder.

Description

 Specification

 Residual concrete processing method, recycled cement and concrete aggregate

 [oooi] The present invention is obtained by a processing method in which return raw concrete and Z or raw concrete sludge as residual concrete are separated and recovered into aggregate and fine powder by dry processing, and obtained by this processing method. The present invention relates to recycled cement and concrete aggregate.

 Background art

 [0002] Ready-mixed concrete is usually transported to a construction site or civil engineering site by an agitator truck (raw-mixer truck) and unloaded. Depending on the case, a large amount of ready-mixed concrete may remain or cannot be unloaded. And you can take it home as it is.

 [0003] As a method of treating the remaining ready-mixed concrete in this way, there is known a method in which the returned ready-mixed concrete is solidified and then crushed by a crusher, and the crushed concrete is reused as a roadbed material. (See Patent Document 1).

 Thus, what solidifies return ready-mixed concrete is a technology that does not collect aggregate contained in return ready-made concrete, and there is a problem that aggregate cannot be recycled.

 [0004] Conventionally, as a technique for recovering aggregates from returned ready-mixed concrete, a wet process is known in which the returned ready-mixed concrete is washed with water and the aggregate is taken out (see Patent Document 2). ).

 In this way, in the case where the aggregate is extracted by wet processing of the ready-mixed concrete, it is necessary to perform the water-washing process. was there.

 [0005] In addition, raw concrete sludge generated as a result of washing of agitator trucks (raw mixer trucks) and washing of raw concrete factories is processed as waste, which requires a lot of labor and cost. There was a problem that it took.

 [0006] Patent Document 1: Japanese Patent Laid-Open No. 2001-327805

 Patent Document 2: Japanese Patent Laid-Open No. 7-51592

Disclosure of the invention Problems to be solved by the invention

 [0007] The present invention uses return raw concrete or raw concrete sludge which is residual residual concrete having fluidity as a raw material to be processed, and a dry raw material (dry aggregate and / or dry fine powder) as the raw material to be processed. By mixing and stirring, moisture in the residual concrete adheres to the dry raw material and absorbs water, thereby eliminating the fluidity of the residual concrete, obtaining a so-called “para-para” mixed raw material, and converting this mixed raw material into aggregate and fine powder. By classifying, a method for treating residual concrete that can be easily separated and collected and capable of obtaining reusable aggregate and fine powder, and recycled cement and concrete aggregate obtained by this treatment method are provided. The issue is to provide.

 Means for solving the problem

[0008] In order to solve the above problems, the residual concrete processing method of the present invention (Claim 1) is:

 Return raw concrete and Z or green concrete sludge, which are residual raw concrete, are used as raw materials, dry aggregate and / or dry fine powder are used as dry raw materials, and the raw materials are mixed and stirred into the raw materials to be processed. A mixing and stirring step for obtaining a mixed raw material by adhering and absorbing moisture in the dry raw material, and a classification step for classifying the mixed raw material obtained through this mixing and stirring step into aggregates and fine powders are provided. .

 [0009] The method for treating residual concrete according to the present invention (Claim 2) is as follows.

 2. The residual concrete processing method according to claim 1, wherein the dry aggregate as the dry raw material is a dry meteorite aggregate and / or a dry slag aggregate.

 [0010] The method for treating residual concrete according to the present invention (Claim 3) is as follows.

 The method for treating residual concrete according to claim 1 or 2, wherein the dry fine powder as the dry raw material is one or more of dry cement, dry mixed cement, dry green consludge powder, and dry fly ash powder. It was set as the structure which is a combination of.

 [0011] The method for treating residual concrete according to the present invention (Claim 4) is as follows.

 Claim: The method for treating residual concrete according to any one of claims 1 to 3, wherein the mixed raw material is temporarily stored and then sent to a classification step.

[0012] The method for treating residual concrete according to the present invention (Claim 5) is as follows. Claims: In the method for treating residual concrete according to any one of claims 4 to 4, fine powder generated in the mixing and stirring step and / or classification step is collected, and a part or all of the collected fine powder is collected. The recycled cement was obtained by pulverizing as it was or after pulverizing or firing or after calcination.

 [0013] The method for treating residual concrete according to the present invention (Claim 6) is as follows.

 Claim: In the method for treating residual concrete according to any one of claims 5 to 5, the fine powder generated in the mixing and stirring step and / or the classification step is collected, and a part or all of the collected fine powder is collected. It was configured to return to the mixing and stirring step.

 [0014] The method for treating residual concrete according to the present invention (Claim 7) is as follows.

 Claims: The method for treating residual concrete according to any one of claims 6 to 6, wherein a part or all of the mixed raw material is returned to the mixing and stirring step before being classified in the classification step.

 [0015] The method for treating residual concrete according to the present invention (Claim 8) is as follows.

 Claims: The method for treating residual concrete according to any one of claims 7 to 7, wherein a part or all of the aggregate obtained through the classification step is returned to the mixing and stirring step.

 [0016] A method for treating residual concrete according to the present invention (Claim 9) is as follows.

 Claims: The method for treating residual concrete according to any one of claims 8 to 8, wherein the aggregate obtained through the classification step is directly or classified to obtain a concrete aggregate.

 [0017] The method for treating residual concrete according to the present invention (Claim 10) is as follows.

 Claims: The method for treating residual concrete according to any one of claims 9 to 9, wherein in the mixing and stirring step and / or the classification step, the raw material is blown so as to blow air.

 [0018] Further, the recycled cement of the present invention (claim 11),

 It is obtained by the method for treating residual concrete according to claim 5.

[0019] Further, the aggregate for concrete of the present invention (Claim 12) is

It is obtained by the method for treating residual concrete according to claim 9. The invention's effect

 [0020] In the method for treating residual concrete according to the present invention (Claim 1), water in the raw material to be treated, that is, return raw concrete that is residual residual concrete and Z or green concrete sludge adheres to the dry raw material and absorbs water. Therefore, it is possible to eliminate the fluidity of the residual concrete and obtain a so-called para-parallic mixed raw material.

 As a result, the subsequent classification step can be performed by a dry method, so that the classification effort can be reduced and the classification device can be simplified.

 [0021] Further, since the fine powder collected in the mixing and stirring step contains a cement content in the residual concrete, it can be effectively reused as recycled cement.

 [0022] In the residual concrete treatment method of the present invention, the mixed raw material may be temporarily stored before the mixed raw material is classified (claim 4).

 In this way, if the storage time for the mixed raw material is provided, it is possible to perform reliable adsorbed water absorption with the dry raw material.

 [0023] In the residual concrete treatment method of the present invention, the fine powder generated in the mixing and stirring step and / or the classification step is collected, and a part or all of the collected fine powder is directly or pulverized or baked. Or it can grind | pulverize after a baking process (Claim 5). Residual concrete contains cement. Therefore, the fine powder collected in the mixing and agitation process and classification process contains cement. Therefore, this fine powder can be used as it is or after pulverization, firing, or calcination. If it is pulverized, it can be regenerated as cement.

 [0024] In the residual concrete treatment method of the present invention, part or all of the mixed raw material before classification can be returned to the mixing and stirring step as a dry raw material (claim 7). If the mixed raw material before classification is returned as a dry raw material in this way, the quality of the mixed raw material can be improved.

[0025] In the present invention, part or all of the fine powder collected in the mixing and stirring step and / or classification step, or part or all of the aggregate obtained through the classification step is returned to the mixing and stirring step as a dry raw material. (Claim 6 and Claim 8).

Thus, the fine powder collected in the mixing and stirring process and the classification process, the aggregate obtained through the classification process By returning to the mixing and stirring step as a dry raw material, the quality of the mixed raw material can be improved.

 [0026] In the residual concrete processing method of the present invention, the aggregate obtained by classification can be obtained as it is or by classifying the aggregate as it is (claim 9).

 [0027] When only the fine powder is used as the dry raw material, the recovered aggregate is only the aggregate contained in the residual concrete and can be used as a concrete aggregate that is almost similar to the virgin aggregate.

 [0028] In the method for treating residual concrete according to the present invention, air (or hot air) may be blown against the raw material by blowing air in the mixing and stirring step and / or the classification step. Item 10).

 In this way, when air (hot air) is blown against the raw material, drying of the raw material can be promoted, and the mixed raw material can be further brought into a paralyzed state.

 The mixed raw material is also promoted to dry due to the heat generated by the cement contained therein. Brief Description of Drawings

 FIG. 1 is a flowchart showing a first embodiment of a method for treating residual concrete according to the present invention.

 FIG. 2 is a flowchart showing a second embodiment of the method for treating residual concrete according to the present invention. Explanation of symbols

[0030] 1 Return raw concrete

 2a Dry crushed aggregate (Dry aggregate)

 2b Dried raw consludge powder (dry fine powder)

 3 Mixing and stirring process

 30 Mixed raw materials

 31 Blower

 4 Classification process

 40 fine powder

 40a Baking treatment

 40b grinding

40c recycled cement 41 Fine aggregate

 42 Coarse aggregate

 43 Coarse aggregate

 44 Blower

 49 Dust collector

 5 Storage

 8 Fine powder

 81 Baking treatment

 82 Grinding

 83 Recycled cement

 BEST MODE FOR CARRYING OUT THE INVENTION

 FIG. 1 is a flowchart showing a first embodiment of a method for treating residual concrete according to the present invention.

 This treatment method uses return raw concrete 1 that is residual residual concrete as a raw material to be processed, dry meteorite aggregate 2a that is a dry aggregate as a dry raw material, and the dried crushed stone aggregate 2a is mixed with return raw concrete 1 This is an example.

[0032] The returned ready-mixed concrete 1 is ready-mixed concrete in which crushed stone (coarse aggregate), sand (fine aggregate), cement, and water are mixed at a predetermined design rate. Although it was transported to the civil engineering site, it was taken home without being unloaded at the site due to circumstances.

 In addition, as the ready-mixed concrete 1, it is possible to use various cements specified in JIS and special cements other than those specified in JIS, such as Portland cement type and mixed cement type, which have no special restrictions on the type of cement.

[0033] Note that as the raw material to be treated, raw concrete sludge which is residual raw concrete of return raw concrete 1, and a mixture of return raw concrete 1 and raw concrete sludge can be used.

Ready-mixed concrete sludge is a scrap of ready-mixed concrete that is generated when washing agitator trucks (clean-mixed mixer trucks) or cleaning ready-mixed conditions. It is a mixture of fine crushed stone powder, cement, and a large amount of water. [0034] As the dry aggregate, dry crushed aggregate 2a and / or dry slag aggregate can be used, which adheres and absorbs moisture in residual residual concrete, and is in a dry state. Or use a completely dry one.

 As the dry crushed aggregate 2a, virgin aggregate and / or recycled aggregate can be used, and as the dried slag aggregate, blast furnace slag aggregate and Z or dust melting slag aggregate can be used. it can. This blast furnace slag aggregate and / or waste molten slag aggregate is obtained by crushing a molten slag lump by quenching in water, sizing and drying.

 [0035] In the examples, dry crushed aggregate 2a having a particle size of sieving and under 40 mm is used as a dry raw material. Not limited to this, there is no restriction on the particle size, such as a sieve size under 25 mm, but it is usually considered appropriate to be under 25 mm to under 40 mm.

 [0036] In the mixing and stirring step 3, the mixed raw material 30 is obtained by mixing and stirring the returned green concrete 1 and the dried crushed aggregate 2a.

 The mixing ratio in this case is determined by the amount of dry crushed aggregate 2a mixed according to the amount of moisture in the ready-mixed concrete 1, and the mixed aggregate 30 that has undergone the mixing and stirring step 3 has a surface water of 5% or less (for example, Therefore, it is considered appropriate to adjust so that the ready-mixed ready-mixed concrete: dry crushed aggregate = 1: 3).

 [0037] As the mixing and stirring device in the mixing and stirring step 3, for example, a rotor is eccentrically provided in a horizontal rotary drum, and the input raw materials (returned raw concrete 1 and dry crushed aggregate 2a) are used as the rotary drum and the rotor. It is possible to use a device (for example, manufactured by Shinroku Seiki Co., Ltd .: Hurricane) that is mixed and stirred while rotating in reverse.

[0038] In addition, as a mixing and stirring device, a lifting plate is protruded from the inner surface of the horizontal rotary cylindrical drum, and the horizontal rotary cylindrical drum is rotated in a state where the raw material is put into the horizontal rotary cylindrical drum. An apparatus in which the raw materials are mixed and stirred can be used. In this case, since the raw material is lifted upward by the lifting plate and falls from there, mixing and stirring can be performed efficiently.

In this case, when a cylindrical sieve (trommel) is integrally connected to the end of the horizontal rotating cylindrical drum, the raw materials (returned raw concrete 1 and dry crushed aggregate 2a) charged into the horizontal rotating cylindrical drum are converted into the horizontal type. The mixed raw material 30 is obtained by mixing and stirring with a rotating cylindrical drum. The mixed raw material 30 can be continuously classified by the cylindrical sieve.

 Thus, the configuration in which the classification step 4 is provided continuously after the mixing and stirring step 3 is also included in the present invention, and in this case, the work efficiency can be improved.

 [0039] The raw materials (returned raw concrete 1 and dried crushed aggregate 2a) can be configured to be conveyed by a screw conveyor. In the screw conveyor, when the raw materials are conveyed, they are mixed and stirred at the same time. Such a screw conveyor can be used as a mixing and stirring device in the mixing and stirring step of the present invention.

 [0040] Other than that, the mixing and stirring device used in the mixing and stirring step 3 of the present invention is not limited to the above-described device, and the point is that residual concrete (returning) can be used as a mixing and stirring device. Mixing raw concrete 1) and dry raw material (dried crushed aggregate 2a) allows the dry raw material to adhere to and absorb moisture from the remaining raw concrete, and the mixed raw material 30 is put into a crushed state. As long as it can be used, it can be used regardless of batch type or continuous type.

 [0041] The mixing and stirring may be performed only once, or may be performed a plurality of times of two or more times. The water dispersibility required by adsorbing and absorbing water in the residual raw concrete to a dry raw material. Set the number of times, time, and strength to match.

 When mixing and stirring a plurality of times, the same apparatus may be used a plurality of times, or different apparatuses may be used. For example, if the raw material is mixed and stirred by a horizontal rotating cylindrical drum and then conveyed to the classification process by a screw conveyor, mixing and stirring can be performed twice (multiple times) by the horizontal rotating cylindrical drum and screw conveyor. .

[0042] Next, the force for classifying the mixed raw material 30 obtained as described above in the classification step 4 The mixed raw material 30 is temporarily stored (stock) 5 before the classification step 4. preferable. When the return raw concrete 1 and the dry crushed aggregate 2a are mixed and stirred, the water of the return raw concrete 1 is adsorbed and absorbed by the dry crushed aggregate 2a, and the cement cannot be solidified. As a result, the fluidity of the returned ready-mixed concrete 1 is lost, and a so-called “para-para” mixed raw material 30 can be obtained.

In this case, if the amount of dry crushed aggregate 2a is large (for example, return ready-mixed concrete: dry crushed aggregate = 1: 3), quick and reliable adsorbed water absorption is performed. If the total amount is small (for example, return ready-mixed concrete: dry crushed aggregate = 1: 1), it takes time for adsorbed water absorption. In such a case, the mixed raw material 30 is temporarily stored 5 to prevent adsorbed water absorption. It is preferable to classify the mixed raw material 30 after it is sufficiently performed.

 Moreover, the mixed raw material 30 may be temporarily stored for convenience of work process, and such storage is also included in the storage 5 referred to in the present invention.

 The storage time is set according to the blending ratio between the ready-mixed concrete 1 and the dry crushed aggregate 2a, but it is usually 3 hours or more.

[0043] In the classification step 4, the mixed raw material 30 is classified into aggregate and fine powder.

 In this example, fine powder 40 with a sieve size of 0.15 mm or less, fine aggregate 41 with a sieve size under 5 mm, coarse aggregate 42 with a sieve size of 5 mm to 20 mm, and sieve size over 20 mm. Of coarse aggregate 43.

 The fine powder 40 can be collected by a dust collector 49 such as a bag filter, and such collection by the dust collector 49 is also included in the classification in the classification step 4 referred to in the present invention.

 [0044] Further, in the classification step 4, for the purpose of drying the mixed raw material 30 and the purpose of scattering the fine powder 40, the air is blown 44 to blow air (or hot air) into the classification device. It is.

 [0045] The fine aggregate 41 having a sieve size under 5 mm is used as a fine aggregate for concrete (for raw concrete and for secondary concrete products).

 Coarse aggregate 42 having a sieve size of 5 mm to 20 mm is used as coarse aggregate for concrete (for ready-mixed concrete and for secondary concrete products).

[0046] In addition, the fine aggregate 41 and Z obtained by classification as described above, or a part or all of the coarse aggregate 42 can be returned to the mixing and stirring step 3 as a dry raw material.

 In addition, part or all of the fine powder 40 obtained by classification can be returned to the mixing and stirring step 3 as a dry raw material.

When the aggregates 41 and 42 fine powder 40 obtained by classification in this way are returned to the mixing and stirring step 3, the quality of the mixed raw material 30 can be improved, and the aggregated raw material 1 can also be mixed. The amount of dry raw material (dry crushed aggregate 2a) can be reduced. [0047] Further, the fine powder 40 can be used as it is as a recycled cement or a cement extender, and the recovered fine powder 40 is baked 40a (for example, about 800 ° C.) to produce a recycled cement. 40c can be obtained.

 Further, the regenerated cement 40c can be obtained by pulverizing 40b of the fine powder 40 with a ball mill or the like.

[0048] Also in the mixing and stirring step 3, the fine powder 8 generated by the mixing and stirring is collected by a bag filter or the like, and the collected fine powder 8 is baked 81. Thus, if the recovered fine powder 8 is subjected to a baking process 81 (for example, about 800 ° C.), a regeneration cement 83 can be obtained.

 Also, the recycled cement 83 can be obtained by pulverizing 82 the fine powder 8 with a ball mill or the like.

 The recovered fine powder 8 may be used as it is as recycled cement or cement extender.

 Alternatively, a part or all of the recovered fine powder 8 can be returned to the mixing and stirring step 3 as a dry raw material.

 [0049] Further, the mixed raw material 30 obtained in the mixing and stirring step 3 is partly or completely dried before being classified in the classification step 4 in addition to being classified into aggregates and fine powders in the classification step 4. It can be returned to the mixing and stirring step 3 as a raw material.

 When the mixed raw material 30 is returned in this way, the quality can be improved, and the amount of dry meteorite aggregate 2a mixed with the recycled concrete 1 can be reduced.

[0050] In the mixing and stirring step 3 in the mixing and stirring step 3, the air (or hot air) may be blown 31 during the mixing and stirring.

 Since the air blows against the raw material by the air blow 31, the drying is promoted, and the mixed raw material 30 can be further put into a paraffin state.

 Note that the exhaust of the dust collector 49 is used for the air blow 31 and the air blow 44.

FIG. 2 is a flowchart showing a second embodiment of the method for treating residual concrete according to the present invention.

This treatment method uses return raw concrete 1 that is residual residual concrete as a raw material to be treated, dry raw consludge powder 2b that is a dry fine powder as a dry raw material, and the dried raw consludge. This is an example in which powder 2b is mixed with returned green concrete 1.

 In describing the second embodiment, differences from the first embodiment will be described.

 [0052] Dry green consludge powder 2b used as a dry raw material is obtained by drying green consludge and contains fine crushed stone powder and cement.

 In addition to this, any one or a combination of dry cement, dry mixed cement, and dry fly ash can be used as the dry raw material. The dry fine powder used as the dry raw material is residual concrete. For adsorbing and absorbing moisture in the inside, use one that is either dry or absolutely dry.

 In general, fine powder refers to those having a sieve size of 0.074 mm or less or 0.15 mm or less, but even if a small amount is included, the majority of the fine powder is included. Those that occupy are included in the fine powder referred to in the present invention.

[0053] Then, in the mixing and agitation step 3, the return raw concrete 1 and the dried green consludge powder 2b are mixed and agitated to obtain a mixed raw material 30.

[0054] In the classification step 4, the mixed raw material 30 is classified into aggregate and fine powder.

 In this embodiment, the fine powder 40 having a sieve size of 0.15 mm or less, the fine aggregate 41 having a sieve size of under 5 mm, and the coarse aggregate 42 having a sieve size of 5 mm to 20 mm are classified.

 [0055] The fine aggregate 41 having a sieve size under 5 mm is used as a fine aggregate for concrete (for raw concrete, for secondary concrete products).

 Coarse aggregate 42 having a sieve size of 5 mm to 20 mm is used as coarse aggregate for concrete (for ready-mixed concrete and for secondary concrete products).

 [0056] In the first embodiment, an example in which dry aggregate (dried crushed aggregate 2a) is used as a dry raw material is shown. In the second embodiment, dry fine powder (dry raw consludge powder 2b) is used as a dry raw material. Although the example used was shown, dry aggregate and dry fine powder can be combined (mixed) and used as a dry raw material.

Claims

The scope of the claims  [1] Residual ready-mixed concrete and Z or ready-mixed sludge as residual raw materials are used as raw materials for treatment, dry aggregate and / or dry fine powder are used as dry raw materials, and the raw materials to be treated are mixed and stirred. A mixing and stirring step for obtaining a mixed raw material in which moisture in the raw material to be treated is adhered to and absorbed by the dry raw material, and a classification step for classifying the mixed raw material obtained through the mixing and stirring step into an aggregate and a fine powder are provided. A method for treating residual concrete.  2. The method for treating residual concrete according to claim 1, wherein the dry aggregate as the dry raw material is a dry crushed aggregate and / or a dry slag aggregate. [3] The residual life according to claim 1, wherein the dry fine powder as the dry raw material is any one or a combination of dry cement, dry mixed cement, dry green sludge powder, and dry fly ash powder. Concrete processing method. [4] The method for treating residual concrete according to claim 1, wherein the mixed raw material is temporarily stored and then sent to a classification step. [5] The fine powder generated in the mixing and stirring step and / or the classification step is collected, and a part or all of the collected fine powder is recovered as it is or after being pulverized or baked or pulverized. The method for treating residual concrete according to claim 1, wherein cement is obtained.  [6] The remainder according to claim 1, wherein the fine powder generated in the mixing and stirring step and / or classification step is collected, and a part or all of the collected fine powder is returned to the mixing and stirring step. Raw concrete processing method. [7] The method for treating residual concrete according to claim 1, wherein a part or all of the mixed raw material is returned to the mixing and stirring step before being classified in the classification step. [8] The method for treating residual concrete according to claim 1, wherein a part or all of the aggregate obtained through the classification step is returned to the mixing and stirring step. 9. The method for treating residual concrete according to claim 1, wherein the aggregate obtained through the classification step is classified as it is or obtained to obtain aggregate for concrete. [10] In the mixing and stirring step and / or classification step, air is blown so as to blow air on the raw material. The method for treating residual concrete according to claim 1. [11] A recycled cement obtained by the method for treating residual concrete according to claim 5.  [12] An aggregate for concrete obtained by the method for treating residual concrete according to claim 9.