JP2010175476A - Method for confirming dispersibility of short fiber contained in concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for confirming dispersibility of short fibers, capable of easily confirming a dispersed state of short fibers regardless of a kind thereof, when a formwork is filled with concrete containing the short fibers. <P>SOLUTION: Once a predetermined time has passed after filling with high-fluidity concrete 1, a formwork cover plate 3a is removed and a concrete sampler 10 is inserted into a target concrete sampling area. The concrete sampler 10 includes a tubular frame 10a for preventing an inflow of the high-fluidity concrete 1 into the target concrete sampling area from the surroundings, and flanges 10b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dispersibility confirmation method for confirming the dispersibility of short fibers when concrete containing short fibers is filled in a formwork.

  When making concrete structure by filling concrete containing fiber into the formwork, in order to obtain sufficient reinforcing effect by fiber, make sure that the fiber is evenly dispersed in the concrete structure That is important.

Therefore, Patent Document 1 discloses a method of confirming a fiber dispersion state by irradiating concrete containing fibers with X-rays. In this method, X-ray images are acquired by irradiating concrete containing fibers with X-rays, and the X-ray images are subjected to image processing based on the difference in density to confirm the dispersion state of the fibers.
JP-A-7-146256

  However, in the method described in Patent Document 1, when the fiber is a steel fiber, the dispersion state can be confirmed because it appears in an X-ray image. However, when the fiber is a resin fiber such as vinylon fiber or polypropylene fiber, X There was a problem that the dispersion state could not be confirmed because it was not shown in the line image. In addition, an apparatus for acquiring an X-ray image becomes expensive, and it is necessary to take a measure for protecting against X-rays, which is complicated.

  The present invention has been made in view of such problems, and when filling concrete containing short fibers into a formwork, it is possible to easily confirm the dispersion state of short fibers regardless of the type of short fibers. An object of the present invention is to provide a method for confirming dispersibility of possible short fibers.

  In order to achieve the above object, the present invention provides a dispersibility confirmation method for confirming the dispersibility of the short fibers when concrete containing short fibers is filled in a mold, and the inside of the concrete filled in the mold is A step of inserting a cylindrical concrete sampling device into the concrete sampling target location so as to surround the concrete sampling target location, a step of sampling the concrete inside the concrete sampling device, and a shortness included in the collected concrete And a step of confirming a mixed state of the fibers.

  According to the present invention, since the cylindrical concrete sampler is inserted so as to surround the concrete collection target portion, it is possible to prevent the surrounding concrete from flowing into the concrete collection target portion. Therefore, it is possible to accurately extract only the concrete at the concrete extraction target portion.

  In the method for confirming dispersibility of short fibers according to the present invention, in the step of collecting the concrete, if the concrete inside the concrete collector is sampled sequentially from a shallow position to a deep position, dispersion in the depth direction is performed. Sex can be confirmed.

  In the method for confirming dispersibility of short fibers according to the present invention, when a concrete segment constituting an annular covering body is manufactured, the concrete filled in the mold is not deformed even if the mold is removed. If it is further provided with a step of standing for a predetermined time until it hardens, the concrete as a sample can be collected by removing the lid mold. According to such a method, the present invention can be applied to a segment manufactured using a lid mold.

  In the method for confirming dispersibility of short fibers according to the present invention, the concrete sampler has a cylindrical frame for enclosing a concrete collection target portion in the filled concrete, and an outer end toward the upper end of the frame. It is good also as providing the flange attached so that it might protrude.

  According to the present invention, after collecting a concrete sample, the concrete sampler can be extracted from the concrete by holding the flange. Therefore, the concrete collector can be reused.

  According to the present invention, it is possible to collect concrete at an arbitrary collection target location in a mold. Further, the dispersion state of the short fibers contained in the concrete filled in the mold can be easily confirmed regardless of the type of the short fibers.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a case where the present invention is applied to the production of a concrete segment including short fibers will be described.

  FIG. 1 is a perspective view showing a mold 3 according to the present embodiment. Moreover, FIG.2 and FIG.3 is front sectional drawing which shows the manufacturing process of the segment 5 which concerns on this embodiment.

  As shown in FIGS. 1 and 2, an injection pipe 2 for injecting concrete is inserted into an injection hole 3 b, and a high-fluidity concrete 1 containing polypropylene fibers is filled in the mold 3. Thereafter, as shown in FIG. 3, the injection hole 3b portion of the lid mold plate 3a is finished and allowed to stand for a predetermined time.

  In the present embodiment, the predetermined time is the time from the end of the filling operation until the high-fluidity concrete 1 is hardened so as not to be deformed even when the lid form plate 3a is removed. The predetermined time varies depending on the blending ratio of the components contained in the high-fluidity concrete 1, the thickness, width, length, etc. of the segment 5, and is appropriately determined by testing or the like.

  Next, a method for collecting a specimen according to the present invention will be described. In this case, the segment 5 from which the specimen is collected is for confirming the dispersibility, and is discarded after the collection.

  As shown in FIG. 1 to sampling point no. Suppose that a total of 8 high-fluidity concrete 1 is collected.

  FIG. 1 and sampling point no. It is a figure which shows the state which has extract | collected 2 high fluidity concrete. Moreover, FIG. 6 is a figure which shows the concrete extractor 10 which concerns on this embodiment.

  As shown in FIG. 5, after filling the high-fluidity concrete 1 into the mold 3, the lid mold frame 3 a is removed when the predetermined time has elapsed, and the concrete is collected at the concrete collection target location in the high-fluidity concrete 1. Insert the vessel 10.

  As shown in FIG. 6, the concrete sampler 10 has a cylindrical frame 10 a for preventing the high-fluidity concrete 1 from flowing from the surroundings into the concrete collection target location, and an outer side at the upper end of the frame 10 a. And a flange 10b attached so as to protrude toward the surface.

The frame 10 a is formed such that its horizontal cross-sectional shape is rectangular, and its height is slightly longer than the thickness of the segment 5. Thereby, even if the frame 10a is inserted into the high-fluidity concrete 1 until the lower end of the frame 10a comes into contact with the inner peripheral surface form frame plate 3c, the flange 10b is not buried in the high-fluidity concrete 1.
The flange 10b is used as a handle for gripping the frame 10a when the frame 10a is inserted into and removed from the high-fluidity concrete 1.

  Next, the collection point No. 1 and sampling point no. The case where 2 concrete is extract | collected is demonstrated.

  First, the sampling point No. 1 and sampling point no. The concrete sampler 10 is inserted into a plane position where 2 is present until the lower end of the concrete sampler 10 comes into contact with the inner peripheral form plate 3c.

And collection point no. A predetermined volume of high-fluidity concrete 1 in the depth portion on the outer peripheral side corresponding to 1 is sampled. In this embodiment, 7000 cm ³ of high-fluidity concrete 1 at each sampling point was sampled, for example. Next, the collection point No. No. 1 and a sampling point No. 1 The high fluidity concrete 1 at a position shallower than 2 is collected and removed. Then, the sampling point No. A high-fluidity concrete 1 at a depth portion on the inner peripheral side corresponding to 2 is collected. At that time, since the frame 10a is installed in the high-fluidity concrete 1, the surrounding high-fluidity concrete 1 outside the frame 10a does not flow into the frame 10a.

  Sampling point no. 1 and sampling point no. When the sampling of No. 2 is finished, the concrete sampler 10 is pulled out, for example, the adjacent sampling point No. 3 and sampling point No. 4 is inserted into the plane position where it exists. In the same manner as above, the sampling point No. 3, gap part, sampling point No. Collect high-fluidity concrete 1 in the order of 4. Hereinafter, sampling points No. 5-Collection point no. Up to 8, the high fluidity concrete 1 is collected in the same manner as above.

  The collected sample is, for example, using water in accordance with “JSCE-F 554-1999: Test method for steel fiber mixing rate of steel fiber reinforced concrete” in the concrete standard specification (publisher: Japan Society of Civil Engineers). Aggregates, gravel, and polypropylene fibers are separated from the high-fluidity concrete 1, and only the polypropylene fibers are collected to check the mixed state.

  According to the dispersion confirmation method in the present embodiment described above, after filling the high-fluidity concrete 1 into the mold 3, the high-fluidity concrete 1 is allowed to stand for a predetermined time until the high-fluidity concrete 1 is cured to the extent that it does not deform even if the mold 3 is removed. Therefore, with the lid-type frame plate 3a removed, the cylindrical frame 10a can be inserted into a predetermined position in the high-fluidity concrete 1 to collect the high-fluidity concrete 1 in the frame 10a. Since the lid mold plate 3a is removed, the high-fluidity concrete 1 can be collected easily and in a short time.

  Moreover, it can prevent that the surrounding high fluidity concrete 1 flows in by inserting the cylindrical frame 10a in the concrete extraction object location. Therefore, it is possible to collect only the high-fluidity concrete 1 at the location where the concrete is to be collected.

  Furthermore, since the concrete sampler 10 is provided with the flange 10b, after the high-fluidity concrete 1 is sampled, the flange 10b can be gripped and extracted from the high-fluidity concrete 1. Therefore, the concrete collector 10 can be reused.

  In addition, in this embodiment, although the case where the sampling point of the high fluidity concrete 1 was made into 8 places was demonstrated, it is not limited to this number, The number of sampling is based on the thickness, width, length, etc. of the segment 5 Are different, and the number and position of collection are determined by design and the like.

  Moreover, although this embodiment demonstrated the case where the segment 5 was manufactured as a concrete structure, it is not limited to this, It is applicable when constructing a general concrete structure.

  In the present embodiment, the case where the horizontal cross-sectional shape of the frame 10a is rectangular has been described. However, the present invention is not limited to this, and may be other polygons or circles.

It is a perspective view which shows the formwork which concerns on this embodiment. It is front sectional drawing which shows the manufacturing process of the segment which concerns on this embodiment. It is front sectional drawing which shows the manufacturing process of the segment which concerns on this embodiment. It is a figure which shows the concrete extraction object location for confirming dispersibility. Sampling point no. 1 and sampling point no. It is a figure which shows the state which has extract | collected 2 high fluidity concrete. It is a figure which shows the concrete extractor which concerns on this embodiment.

DESCRIPTION OF SYMBOLS 1 High fluidity concrete 2 Injection pipe 3 Mold 3a Cover mold frame board 3b Injection hole 3c Inner peripheral surface mold board 5 Segment 10 Concrete extractor 10a Frame 10b Flange

Claims (4)

In a dispersibility confirmation method for confirming dispersibility of the short fibers when filling concrete containing short fibers into a mold,
Inserting a cylindrical concrete sampler into the concrete collection target location so as to surround the concrete collection target location in the concrete filled in the mold,
Collecting concrete inside the concrete collector;
And a step of confirming a mixed state of short fibers contained in the collected concrete.   The method for confirming dispersibility of short fibers according to claim 1, wherein, in the step of collecting the concrete, the concrete inside the concrete collector is sequentially collected from a shallow position to a deep position. When producing a concrete segment that forms an annular lining body,
The dispersion of short fibers according to claim 1 or 2, further comprising a step of allowing the concrete filled in the mold to stand for a predetermined time until the concrete is hardened so as not to be deformed even if the mold is removed. Sex confirmation method. The concrete collector is
A cylindrical frame for enclosing the concrete collection target location in the filled concrete;
The short fiber dispersibility confirmation method according to any one of claims 1 to 3, further comprising a flange attached to an upper end portion of the frame so as to protrude outward.

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