JP5038262B2 - Reuse method of green cut shear and concrete structure - Google Patents

Description

  The present invention relates to a method for reusing a green cut shear caused by a green cut performed after concrete placement when constructing a dam body such as a dam, and a concrete structure in which the green cut shear is reused.

  When constructing a dam body such as a dam, after placing the precast concrete, the postcast concrete is cast on the surface side, and this work is repeated to place the concrete. Here, the surface of the pre-cast concrete is covered with a fine particle such as cement called latency, and if post-cast concrete is directly placed on the surface, there may be a problem of water stoppage.

For this reason, after placing the precast concrete, the surface of this precast concrete is green-cut using pressure water or a brush (for example, refer patent document 1). The green cut shear generated by this kind of green cut is transported to, for example, a soil disposal site and processed as industrial waste.
JP-A-9-59960

  However, the green cut shear generated by the green cut contains a lot of concrete aggregate and cement hydrate originally contained in the precast concrete. Green cut scraps are treated as industrial waste because of the risk of elution of hexavalent chromium. However, if the concrete aggregate contained in the green cut scrap is processed as industrial waste as it is, there is a problem that waste of resources is caused.

  Then, the subject of this invention is providing the reuse method of a green cut shear and the concrete structure which can aim at the effective use of resources.

  The method for reusing green cut shear according to the present invention that has solved the above problems is to green-cut the surface of the precast concrete, then form a mortar layer on the surface of the precast concrete, and place the postcast concrete on the surface of the mortar layer. In placing, the green cut shear generated at the time of green cutting is reused as at least one of the concrete aggregate included in the post-cast concrete and the mortar aggregate included in the mortar layer. .

  In the method of reusing green cut shear according to the present invention, the green cut shear generated at the time of green cutting is reused as concrete aggregate included in post-cast concrete or mortar aggregate included in a mortar layer. Since the green cut is performed on the surface of the precast concrete, the concrete aggregate is mixed in the green cut shear. It is considered that this concrete aggregate can be reused as a concrete aggregate contained in post-cast concrete and a mortar aggregate contained in a mortar layer. For this reason, effective use of resources can be achieved.

  Here, from the green cut shear, a fine aggregate of 5 mm or less can be taken out and reused as a mortar aggregate.

  Thus, by extracting a fine aggregate of 5 mm or less and reusing it as a mortar aggregate, the fine aggregate to be reused as a mortar aggregate can be easily screened and extracted from the green cut shear.

  Further, a fine aggregate of 75 μm or more and 5 mm or less is taken out from the green cut shear, washed with water, and reused as a mortar aggregate.

  Thus, a fine mortar aggregate excellent in particle size distribution can be taken out by taking out a fine aggregate of 75 μm or more and 5 mm or less, washing it with water, and reusing it as a mortar aggregate.

  Further, a fine aggregate of 0.5 mm or more and 5 mm or less can be taken out from the green cut shear, washed with water, and reused as a mortar aggregate.

  Thus, a fine mortar aggregate can be taken out by taking out a fine aggregate of 0.5 mm or more and 5 mm or less, washing it with water, and reusing it as a mortar aggregate.

  In addition, it is determined whether or not the green cut shear can be used as a concrete aggregate. When the green cut shear can be used as a concrete aggregate, the green cut shear should be transported to a concrete aggregate manufacturing facility. Can do.

  Thus, a green cut shear can also be used as a concrete aggregate by conveying a green cut shear to a concrete aggregate manufacturing equipment.

  Furthermore, the method for reusing green cut shear according to the present invention that has solved the above-mentioned problem is that the surface of the precast concrete is green-cut as the inner concrete in a dam facility including the inner concrete and the outer concrete. It is characterized by forming a mortar layer on the surface, placing post-cast concrete on the surface of the mortar layer, and reusing the green cut shear generated during green cutting as the concrete aggregate contained in the outer concrete. is there.

  In the method for reusing green cut shear according to the present invention, the green cut shear generated during the green cut is reused as the concrete aggregate contained in the outer concrete. Since the green cut is performed on the surface of the precast concrete, the concrete aggregate is mixed in the green cut shear. For this reason, resources can be effectively used by reusing the green cut shear generated during the green cut as the concrete aggregate contained in the outer concrete.

  In addition, the concrete structure according to the present invention that has solved the above-described problems is a precast concrete whose surface is green-cut, a mortar layer formed on the surface of the precast concrete, and a postcast formed on the surface of the mortar layer. A concrete layer, and the aggregate contained in the green cut shear generated by the green cut is reused as the mortar aggregate contained in the mortar layer and the concrete aggregate contained in the post-cast concrete To do.

  According to the green cut shear reuse method and concrete structure according to the present invention, it is possible to effectively use resources.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted. FIG. 1 is an overall configuration diagram of a dam in which green cut shear is reused according to the present embodiment.

  As shown in FIG. 1, an outer concrete 2 and an inner concrete 3 are placed in a dam 1 where green cutting shear is reused according to the present embodiment. The dam 1 is a gravity concrete dam, and the inner concrete 3 is placed by an RCD (Roller Compacted Dam-Concrete) method.

  As shown in FIG. 2, the inner concrete 3 is formed of concrete layers 11, 12. The concrete layers 11, 12... Are placed by an RCD construction apparatus 31 including a vibration roller. Also, cement and concrete aggregate are supplied from the concrete manufacturing equipment 41 to the RCD construction apparatus 31. The concrete production equipment 41 is supplied with concrete aggregate from an aggregate production line 42. Further, the aggregate production line 42 is supplied with a concrete aggregate material such as ordinary crushed stone and a green cut shear that can be used as a concrete aggregate described later.

  A mortar layer 20 is laid between the pre-cast concrete layer 11 and the post-cast concrete layer 12. The mortar layer 20 functions as an adhesive layer between the pre-cast concrete layer 11 and the post-cast concrete layer 12. The mortar layer 20 is laid by the joint mortar laying device 32. Further, the mortar production material including the mortar aggregate is supplied from the joint mortar production equipment 43 to the joint mortar laying device 32. Furthermore, the mortar manufacturing equipment is supplied with normal mortar aggregate and green cut shears that can be used as mortar aggregate described later.

  Moreover, after the placement of the precast concrete layer 11 is completed, the green cutting operation of the surface of the precast concrete layer 11 is performed. The green cutting operation is performed using a green cutting machine 33, and is performed by spraying pressure water onto the surface of the precast concrete layer 11 or brushing the surface of the precast concrete layer 11 with a brush.

  By this green cutting operation, the surface of the precast concrete layer 11 is thinly cut and the latency covering the surface of the precast concrete layer 11 is removed. The thickness of the surface of the precast concrete layer 11 scraped off by the green cutting operation is, for example, about 5 mm. Moreover, the thickness of each concrete layer 11,12 ... is about 1 mm, for example, and the thickness of the mortar layer 20 provided between the concrete layers 11,12 is about 15 mm, for example.

  Further, the green cut shear generated by the green cut is collected in the green cut processing equipment 44, and a predetermined green cut processing is performed. Aggregate produced by the green cutting process is supplied to an aggregate production line 42 or a joint mortar production facility 43 in accordance with its properties and the like.

  Next, the construction procedure of the inner concrete will be described. FIG. 3 is a flowchart showing the construction procedure of the inner concrete. Moreover, the flow of the aggregate in this flowchart is shown with the broken line.

  As shown in FIG. 3, when the inner concrete is constructed, the concrete produced by the concrete production equipment 41 is transported to the inner concrete construction position (S1), and the precast concrete is placed by the RCD construction apparatus (S2). ). Next, after jointing the horizontal joints in the precast concrete (S3), the concrete is compacted (S4). Concrete compaction is performed using Viebac (registered trademark) (S4-1), and after rolling and compacting using a vibrating roller (S4-2), surface rolling is performed using a chaptering roller. (S4-3).

  Thus, when the concrete compaction is completed and the concrete placement is completed (S5), the placed concrete is cured (S6). When the concrete is cured, the green portion of the slump portion is cut (S7), and then the green portion of the RCD portion is cut (S8). The green cut of the slump part is generally carried out within one day of the concrete age. In addition, the green cut of the RCD portion is generally performed within 3 to 7 days of concrete age. Green cut is generated by the green cut here. The green cut shear generated here is conveyed to the green cut shear treatment equipment 44.

  Thereafter, cleaning before placing is performed (S9), and the process returns to step S1. When the construction of the precast concrete is completed, the mortar layer 20 is constructed. Construction of the mortar layer 20 is performed by the same procedure as construction of precast concrete. First, the mortar is transported from the joint mortar manufacturing equipment 43 (S1), and the mortar is placed on the surface of the precast concrete that has been constructed (S2). Subsequently, joint cutting of the horizontal joint is performed (S3).

  Then, since the compaction of the mortar layer 20 is not necessary, the placement of the mortar is completed (S5), and the mortar is cured (S6). And since green cutting is also unnecessary, cleaning before placing is performed as it is (S8), and the construction of the mortar layer 20 is finished. When construction of the mortar layer 20 is completed, post-cast concrete is placed on the surface. The construction procedure for post-cast concrete is the same as that for pre-cast concrete.

  Thereafter, the concrete construction and the mortar layer construction are repeated to construct the inner concrete.

  Next, the processing procedure of the green cut shear produced by the green cut of the precast concrete will be described. FIG. 4 is a flowchart showing a processing procedure for green cut shearing.

  As shown in FIG. 4, when green cut (GC) shear occurs from the surface of the pre-cast concrete (S11) when a green cut shear is processed, a dump truck or a cable crane (CC) is used (S12- 1) Discharge outside the bank. Then, it temporarily places in the green cut shear temporary storage place (S13).

  Alternatively, the green cut shear is sucked by a vacuum vehicle and then carried out of the bank (S12-2). At this time, suction is made with a vacuum vehicle while water is applied to the green cut slip, thereby increasing the collection rate of the green cut. Subsequently, sand removal work is performed in the muddy water pit (S12-3). Then, the green cut scraps after the sand removal work are transferred to a green cut slip temporary storage place by a dump truck (S12-4). Then, it is temporarily placed in a green cut shear temporary storage place (S13).

  Thus, there are roughly two methods for carrying out the green cut shear. Depending on which of these two methods is used to carry out the green cut shear, the amount of latency and the amount of cement hydrate product mixed in the green cut shear differ. For this reason, the nature of the green cut shear may differ depending on the method of carrying out the green cut shear.

  Thereafter, it is determined whether the green cut shear temporarily placed in the green cut shear temporary storage place has a quality problem as a concrete aggregate (S14). Whether or not there is a problem in quality as a concrete aggregate is judged by the results of visual selection and various simple tests.

  As a result, when it is determined that the green cut shear has no problem in terms of quality as a concrete aggregate, it can be used as a concrete aggregate. In this case, the green cut shear is reused as the concrete aggregate (S15). For this reason, the green cut shear is transported to the aggregate production line 42 and is put into a raw stone charging facility, a raw sand bottle, or the like.

  If it is determined that the green cut shear has a quality problem as a concrete aggregate, it is determined whether or not the green cut shear satisfies the standard as a mortar aggregate (S16). As a result, when it is determined that the green cut shear satisfies the standard as a mortar aggregate, the green cut shear is applied to a vibration sieve to cut an aggregate of 5 mm or more (S17). Thereafter, the green cut shear applied to the vibration sieve becomes a green cut shear fine aggregate (hereinafter referred to as “GC fine aggregate”), which is transported to the joint mortar manufacturing facility 43 and stocked in the joint mortar manufacturing facility 43 ( S19).

  On the other hand, when it is determined that the green cut shear does not satisfy the standard for mortar aggregate, cleaning and classification are performed using a high mesh separator (S18). Thereafter, the green cut scraps cleaned and classified using a high mesh separator or the like become a GC fine aggregate, transported to the joint mortar manufacturing facility 43, and stocked in the mortar manufacturing facility 32 (S19). The properties of the GC fine aggregate will be further described later.

  After that, the GC aggregate and the GC fine aggregate transported to the joint mortar manufacturing facility 43 are mortar manufactured at the batcher plant (S20-1), manufactured using the mortar spraying plant (S20-2), and an agitator. It is distributed to manufacturing (S20-3) using the mixing effect of the car. Thus, the green cut shearing process is completed.

  Next, the GC fine aggregate obtained by performing predetermined processing (S15, S16) on the green cut shear will be described. In order to judge the applicability of using the GC fine aggregate as the mortar aggregate, the present inventors prepared samples of GC fine aggregates classified into three types, and examined the applicability of each.

  As the GC fine aggregate, a GC fine aggregate of 5 mm or less (hereinafter referred to as “first sample”), a GC fine aggregate of 75 μm to 5 mm (hereinafter referred to as “second sample”), and a GC of 0.5 mm to 5 mm. A fine aggregate (hereinafter referred to as “third sample”) was prepared. Here, the first sample was not washed with water, and the second sample and the third material were washed with water.

  The first sample was a GC fine aggregate from which raw materials were directly collected from a green cut shear temporary storage place and coarse aggregates exceeding 5 mm were removed by sieving. The second sample was a GC fine aggregate having a particle size of 75 μm or more and 5 mm or less, which was collected by sieving while collecting raw materials from a green cut shear temporary storage site and washing with water. Furthermore, the third sample was a GC fine aggregate with a particle size of 0.5 mm or more and 5 mm or less collected by sieving while being collected from a green cut shear temporary storage and washed with water.

  About these 3rd data from the 1st sample, the test about whether the standard as a fine aggregate for concrete was satisfy | filled was done. As reference standards in this test, the concrete standard specifications “dam edition” and “construction edition” established in 2007 were used. The test results are shown in FIG.

  As shown in FIG. 5, for the first sample, only the absolute dry density item of “Construction” was unsuitable, and all other items were suitable. In addition, with regard to the second sample, both the “dam” and “construction” results were suitable for all items. On the other hand, in the third sample, the particle size distribution was unsuitable for both “dam knitting” and “construction knitting”, but other items were suitable.

  Among the above results, the reason why the absolute dry density item in the first document of “Construction” was unsuitable is that there was an error in grasping the surface dry state by mixing solidified materials such as cement hydrate and surface corn. Etc. are considered. In addition, the reason why the third sample was unsuitable for the item of particle size distribution was that aggregates of 0.5 mm or less were removed by sieving, so that the particle size bone that should fall within the particle size range of 0.5 mm or less It is thought that there was no material.

  From the test results shown in FIG. 5, the standard value of the aggregate for concrete was satisfied in any of the first sample to the third material.

  Next, the results of tests on the fresh properties and compression test strength of mortar using the first to third samples will be described. In this test, mortar properties were compared by a laboratory test using normal fine aggregates currently used and the first to third samples. The results are shown in FIGS.

  Here, FIG. 6 shows the mortar composition, and FIG. 7 shows the results of the fresh test and the compressive strength test. In FIG. 6, W represents water, C represents cement, F represents an admixture, and S represents fine aggregate. Furthermore, CT in FIG. W represents unit volume weight.

  As shown in FIG. 7, there is a large difference between the case of using the normal fine aggregate and the case of using the first sample to the third sample, both in the fresh test result and the compressive strength test result. I was not able to admit. From this result, it was found that any of the first to third samples can be suitably used as an aggregate for mortar.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in each of the above embodiments, the green cut shear is used as an aggregate for post-cast concrete or mortar, but it can be used as a concrete aggregate for concrete constituting the outer concrete in the dam. Further, it is not limited to post-cast concrete on one stage of the pre-cast concrete, and can also be used as a concrete aggregate of post-cast concrete placed on the upper end.

  Moreover, in the said embodiment, the dam is mentioned as a facility which casts concrete as a concrete structure used as object. On the other hand, concrete structures such as facilities where concrete is placed over a wide range and green cutting is performed can also be targeted.

It is a whole block diagram of a dam in which green cut shear is reused. It is a typical front sectional view of a dam body in a dam. It is a flowchart which shows the construction procedure of inner side concrete. It is a flowchart which shows the process sequence of a green cut slip. It is a table | surface which shows the result of the test done about the specification as a fine aggregate for concrete. It is a table | surface which shows the mortar mixing | blending of each sample used for the fresh test and the compressive strength test. It is a table | surface which shows the result of a fresh test and a compressive strength test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dam, 2 ... Outer concrete, 3 ... Inner concrete, 11 ... Pre-cast concrete layer, 12 ... Post-cast concrete layer, 20 ... Mortar layer, 31 ... RCD construction apparatus, 32 ... Jointing mortar laying apparatus, 33 ... Green Cutting machine, 41 ... concrete production equipment, 42 ... aggregate production line, 43 ... joint mortar production equipment, 44 ... green cut processing equipment.

Claims (7)

After green cutting the surface of the precast concrete, forming a mortar layer on the surface of the precast concrete, and in placing the postcast concrete on the surface of the mortar layer,
The green cut shear generated during the green cutting is reused as at least one of a concrete aggregate included in the post-cast concrete and a mortar aggregate included in the mortar layer. How to Use.   The method for reusing a green cut shear according to claim 1, wherein a fine aggregate of 5 mm or less is taken out of the green cut shear and reused as the mortar aggregate.   The method for reusing green cut shears according to claim 1, wherein fine aggregates of 75 µm or more and 5 mm or less are taken out from the green cut shears, washed with water, and reused as the mortar aggregates.   The method for reusing a green cut shear according to claim 1, wherein a fine aggregate of 0.5 mm or more and 5 mm or less is taken out from the green cut shear, washed with water, and reused as the mortar aggregate. Determine whether the green cut shear can be used as a concrete aggregate,
The method for reusing a green cut shear according to claim 1, wherein the green cut shear is transported to a concrete aggregate manufacturing facility when it can be used as a concrete aggregate. As the inner concrete in a dam facility with inner concrete and outer concrete, the surface of the precast concrete is green cut, then a mortar layer is formed on the surface of the precast concrete, and the postcast concrete is cast on the surface of the mortar layer. Set up
A method of reusing green cut shears, wherein the green cut shears generated during the green cutting are reused as concrete aggregates contained in the outer concrete. The surface is green-cut pre-cast concrete, mortar layer formed on the surface of the pre-cast concrete, and post-cast concrete layer formed on the surface of the mortar layer,
A concrete structure in which the aggregate contained in the green cut shear generated by the green cut is reused as the mortar aggregate contained in the mortar layer and the concrete aggregate contained in the post-cast concrete .

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