Resin molds for concrete strength test specimens

Abstract

To provide a box type resin flask for forming a test piece for concrete strength examination capable of preventing the deformation that the facing two sides of the long side in the flask are outwardly swollen upon filling concrete to control the dimensional allowance within the prescribed one.SOLUTION: A resin flask 1 for a test piece for concrete strength examination composed of: a resin flask body part 2 to form into a box type shape by four sides 4A to 4D in a circumferential direction and a bottom 5; and a resin flange part 3 provided along the circumferential direction so as to surround the opening A of the flask body part 2, in which plural stripes of ribs 6 are continuously formed at the outer circumferential face of the flask body part 2 at prescribed intervals. The four sides 4A to 4D in the circumferential direction are made of facing two sides 4A, 4B on the long side and facing two sides 4C, 4D on the short side, and a deformation preventive metal fitting 10(11) for preventing the deformation that the facing 2 sides 4A, 4B on the long side are outwardly swollen upon filling concrete is detachably installed.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a resin mold for producing specimens for concrete flexural strength tests and length deformation tests.

Background Art

[0002] One of the concrete strength tests is the flexural strength test, and the method of making specimens is specified in Japanese Industrial Standard: JIS A1132. And several molds for producing specimens for this flexural strength test have been proposed.

[0003] For example, in Patent Document 1 below, it includes a bottom plate, two side plates erected on the bottom plate, and two end plates erected between the two side plates erected on the bottom plate, and is assembled and fixed in a rectangular parallelepiped shape with an open upper part. It is a mold for a concrete flexural strength test specimen, and the side plates and the end plates are configured by tightening through a connecting member that penetrates and connects the side plates and the end plates. A mold for a concrete flexural strength test specimen is disclosed.

[0004] However, in the case of the mold according to Patent Document 1, the number of steel parts is large, the assembly is complicated, the steel mold is heavy, the manual assembly work is very difficult, and not only is the labor and cost of the work high, but also after demolding, since it needs to be reused, mold cleaning is required after use, and there is also a problem that the labor and cost of the cleaning work are high.

[0005] Therefore, the present applicants proposed, in Patent Document 2 below, a box-shaped mold for forming a specimen for a concrete strength test, in which the side surface and the bottom surface are integrally formed in a box shape made of synthetic resin, a flange portion with a required width is formed on the outer peripheral portion of the upper surface of the box shape, and a plurality of ribs are continuously formed at required intervals on the outer peripheral portions of the side surface and the bottom surface. A lightweight resin mold for a concrete strength test specimen was proposed.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-142108 [Patent Document 2] Japanese Patent Publication No. 2020-101500 [Overview of the project] [Problems that the invention aims to solve]

[0007] According to the formwork described in Patent Document 2, since it is a one-piece molded product made of resin, it does not require assembly work like conventional steel formwork, and because there are no gaps like in steel formwork, concrete does not leak. Furthermore, it is lightweight and easy to carry, resulting in improved workability and significant cost reduction.

[0008] However, because the material is resin, insufficient rigidity sometimes caused deformation, such as outward bulging on the two opposing long sides when concrete was filled in, resulting in the dimensional error of the test specimen exceeding the allowable dimensions. Furthermore, Japanese Industrial Standard JIS A1132 stipulates that the dimensional tolerance of a test specimen should be within 0.5% of the cross-sectional width, and the angle between the side and bottom of the test specimen should be 90 ± 0.5°. ° It is stipulated that this shall be the case.

[0009] Furthermore, in the aforementioned formwork, in order to facilitate removal after concrete filling, a pair of V-shaped grooves are provided close together at the four outer corners of the box-shaped section, extending from the side to the flange section, and the corners are peeled away from the concrete by tearing the grooves. However, this removal process is laborious as it involves manually tearing the resin formwork, and there has been a desire to simplify the removal process.

[0010] Therefore, the main objective of the present invention is to prevent deformation in which two opposing long sides of a box-shaped resin formwork for forming concrete strength test specimens from bulging outward when concrete is filled into the formwork, and to keep the dimensions of the specimen within a predetermined dimensional tolerance.

[0011] Secondly, the resin formwork is intended to facilitate the removal process after concrete filling. [Means for solving the problem]

[0012] To solve the above problems, the present invention according to claim 1 comprises a resin formwork body having one side as an opening and forming a box shape with four circumferential sides and a bottom surface, and a resin flange portion provided along the circumferential direction so as to surround the opening of the formwork body, and wherein a plurality of ribs are continuously formed at predetermined intervals on the outer surface of the formwork body, in a resin formwork for a concrete strength test specimen, The four circumferential sides consist of two opposing long sides and two opposing short sides, and deformation prevention fittings are detachably installed to prevent the two opposing long sides from bulging outward when concrete is filled in. Furthermore, the dimensional tolerance of the test specimen shall be within 0.5% of the cross-sectional width and the angle between the side and bottom of the test specimen shall be 90 ± 0.5°, as specified in Japanese Industrial Standard: JIS A1132. The deformation prevention fitting is made of a rod-shaped steel material processed into a U-shape or U-shape, and the rod-shaped steel material is composed of a relatively large-diameter main body portion processed into a U-shape or U-shape, and relatively small-diameter fitting pins extending from both end faces of the main body portion, and through holes are formed in the center of the flange portion on the long side, and the fitting pins of the rod-shaped steel material are inserted into the through holes to prevent deformation of the two opposing long sides. A resin mold for concrete strength test specimens is provided, characterized by the following:

[0013] In the invention described in claim 1 above, deformation prevention fittings are detachably installed to prevent deformation in which the two opposing long sides bulge outward when concrete is filled, thereby preventing deformation of the resin formwork and making it possible to keep the dimensions of the test specimen within a predetermined dimensional tolerance.

[0014] The deformation prevention fitting is, The deformation prevention fitting is made of a rod-shaped steel material processed into a U-shape or U-shape, and the rod-shaped steel material is made of a relatively large-diameter main body portion processed into a U-shape or U-shape, and relatively small-diameter fitting pins extending from both end faces of the main body portion, and it is desirable that through holes be formed in the center of the flange portion on the long side, and that deformation of the two opposing long sides be prevented by inserting the fitting pins of the rod-shaped steel material into the through holes.

[0015] As part of the present invention according to claim 2, a resin formwork for a concrete strength test specimen according to claim 1 is provided, wherein the resin formwork is made of ABS resin, polyethylene resin, or polypropylene resin.

[0016] The invention described in claim 2 above provides examples of suitable materials for resin molds. For example, it is desirable to use ABS resin, polyethylene resin, or polypropylene resin as the material for the resin mold.

[0017] Claim 3 Claim 1, relating to the present invention, wherein in the flange portion, a plurality of slit grooves are formed over a section from the edge of the opening to the outer edge of the flange portion, and a cut groove with a V-shaped cross-section that is thinned over a section from the outer surface of the formwork body portion to the bottom surface so as to be substantially continuous with the slit grooves. 、2 A resin mold is provided for concrete strength test specimens as described in any of the following.

[0018] The above claims 3 In the described invention, multiple slit grooves are formed in the flange portion of the resin mold, extending from the edge of the opening to the outer edge of the flange portion. Additionally, a V-shaped thinned groove is formed on the outer surface of the mold body, extending to the bottom surface, substantially continuous with the slit grooves. As a result, the slit grooves are formed in the flange portion, which is the most difficult to tear, and are pre-cut. This allows for easy demolding by grasping each of the several separated flange pieces with pliers or the like and peeling them off.

[0019] Claim 4 The present invention relates to the claim that the slit groove is formed in the flange portion on the opposing short side of the flange portion. 3 A resin mold is provided for the concrete strength test specimens described.

[0020] The above claims 4In the described invention, the slit groove is formed in the flange portion on the opposite short side within the flange portion. Since deformation becomes a problem for the opposing long side flange portions as described above, forming a slit groove in these long side flange portions would result in promoting deformation. Therefore, it is desirable to form the slit groove in the short side flange portion where deformation is not a problem.

Advantages of the Invention

[0021] As described in detail above, according to the present invention, in a box-shaped resin mold for forming a specimen for a concrete strength test, when concrete is filled, it is possible to prevent the two side surfaces on the long side of the mold from bulging outward, and to keep the specimen dimensions within a predetermined dimensional tolerance.

[0022] Also, in the resin mold, it becomes possible to facilitate the demolding operation after filling with concrete.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view of the resin mold 1 according to the present invention. [Figure 2] It is a plan view thereof. [[ID=2,4]] [Figure 3] It is a front view thereof. [Figure 4] It is a right side view thereof. [Figure 5] It is a bottom view thereof. [Figure 6] Showing the deformation prevention fitting 10, (A) is a front view and (B) is a side view. [Figure 7] It is an installation guide diagram of the deformation prevention fitting 10. [Figure 8] It is a diagram showing the second deformation prevention fitting 11 and its installation guide. [Figure 9] It is a plan view showing a deformation example of the resin mold 1. [Figure 10] It is a perspective view showing a deformation example of the second deformation prevention fitting. [Figure 11] It is a front view showing a deformation example of the first deformation prevention fitting 10. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0025] As shown in Figure 1, the resin formwork 1 for concrete strength test specimens according to the present invention is a box-shaped formwork, and its material is made of synthetic resins such as ABS resin, which has excellent heat resistance, mechanical strength, oil resistance, impact resistance, gloss, and processability, polyethylene resin, preferably high-density polyethylene resin, or polypropylene resin, which has good release properties from concrete. Among these, ABS resin is preferable in terms of mechanical strength, impact resistance, and processability.

[0026] The test specimens to be manufactured shall be square prisms in accordance with JIS A1132, with standard cross-sectional dimensions of 100mm x 100mm or 150mm x 150mm. Furthermore, the length L of the test specimen shall be at least 80mm longer than three times the length B of one side of the cross-section.

[0027] The resin formwork 1 consists of a formwork body 2 having an opening A on one side and four circumferential sides 4A to 4D and a bottom surface 5, and a resin flange 3 provided along the circumferential direction so as to surround the opening A of the formwork body 2, and multiple ribs 6 are continuously formed on the outer surface of the formwork body 2 at predetermined intervals.

[0028] The main body of the formwork 2 is made of resin with a wall thickness of at least 3 mm, preferably about 3 to 5 mm. The four circumferential sides 4 consist of two opposing long side sides 4A and 4B and two opposing short side sides 4C and 4D.

[0029] To improve the overall rigidity (strength) of the formwork body 2, multiple ribs 6 of the required width and height are continuously formed at predetermined intervals on the outer circumferential surfaces of the sides 4A to 4D and the bottom surface 5. Specifically, multiple ribs 6a, 6a… are formed continuously from the long side surface 4A to the opposing long side surface 4B through the outer surface of the bottom surface 5 at predetermined intervals in the horizontal direction; in the illustrated example, 17 ribs are formed. On the other hand, multiple ribs 6b are formed continuously from the short side surface 4C to the opposing short side surface 4D through the outer surface of the bottom surface 5 at predetermined intervals in the horizontal direction; in the illustrated example, 2 ribs are formed. The ribs 6a, 6a… formed continuously on the long side surfaces 4A, 4B and the bottom surface 5, and the ribs 6b, 6b… formed continuously on the short side surfaces 4C, 4D and the bottom surface 5 intersect in a grid pattern on the outer surface of the bottom surface 5, as shown in Figure 5. The presence of such a large number of ribs 6 significantly increases the strength and rigidity of the formwork body 2. In Figure 4, the hole 7 located approximately in the center of the side surface 4C (4D) is for inserting a steel rod to measure the change in length of the specimen. If the change in length is not to be measured, the hole 7 should not be formed.

[0030] On the other hand, the flange portion 3 is also made of resin with a wall thickness of at least 3 mm, preferably about 3 to 5 mm. For the sake of explanation, as shown in Figure 2, the opposing flange portions on the long sides are designated as 3A and 3B, and the opposing flange portions on the short sides are designated as 3C and 3D. In the illustrated example, these long-side flanges 3A and 3B and the short-side flanges 3C and 3D are given approximately the same width.

[0031] In the flange portion 3, in order to facilitate the demolding work after concrete has been filled and hardened, multiple slit grooves 8 are formed in the section from the edge of the opening A to the outer edge of the flange portion 3, and a V-shaped thinned cut groove 9 is formed on the side surface 4 of the formwork body portion 2 in a section extending to the bottom surface 5 so as to be substantially continuous with the slit grooves 8. Specifically, as shown in Figure 2, three slit grooves 8a to 8c (8d to 8f) are formed on each of the opposing short-side flanges 3C and 3D of the flange portion 3, and as shown in Figure 4, V-shaped thinned cut grooves 9a to 9b are formed in a section extending from the opening end of each slit groove 8 or its vicinity (within 2 mm) to the bottom surface 5 on the side surface 4 of the formwork body portion 2. Note that "substantially continuous" means that in addition to the form that is continuous from the opening end of the slit groove 8, the form that is continuous from its vicinity (within 2 mm) is also included.

[0032] As described above, by forming multiple slit grooves 8 in the flange portion 3 of the resin mold 1, and by forming cut grooves 9a and 9b in the section from there to the bottom surface 5 so as to be substantially continuous, when peeling off the resin mold 1 to remove the test specimen, the flange pieces, which have been divided into several parts by the slit grooves 8, can be grasped with pliers or the like and peeled off to easily demold the mold.

[0033] Incidentally, in the resin formwork 1, deformation prevention fittings 10 (11) are detachably installed to prevent deformation in which the two long sides 4A and 4B of the formwork bulge outward when concrete is filled, and to keep the dimensions of the test specimen within a predetermined dimensional tolerance.

[0034] Figure 6 shows a first example of the deformation prevention fitting. The deformation prevention fitting is a U-shaped steel rod 10. The steel rod 10 consists of a relatively large-diameter main body 10A that is U-shaped, and relatively small-diameter fitting pins 10b, 10b that extend from both end faces of the main body 10A. The fitting pins 10b are gradually tapered toward the tip.

[0035] In the resin mold 1, as shown in Figure 1, through holes 3a and 3b are formed in the center of the flange portions 3A and 3B on the long sides, respectively. As shown in Figure 7, the ends (fitting pins 10b) of the rod-shaped steel material 10 are inserted into the through holes 3a and 3b to prevent deformation of the two opposing long sides 4A and 4B. The fitting pins 10b (maximum diameter) of the rod-shaped steel material 10 are the same diameter as the through holes 3a, and it is important that they fit snugly into the through holes 3a and 3b without any looseness. By installing the rod-shaped steel material 10 horizontally between the long side flanges 3A and 3B, it is possible to effectively prevent deformation of the two opposing long sides 4A and 4B.

[0036] Next, Figure 8 shows a second example of the deformation prevention fitting. The deformation prevention fitting is a processed steel material 11 having a fitting portion K. In the illustrated example, a processed steel material 11 is used which has upright pieces 11a, 11a on both sides, thereby forming an upward-facing U-shaped fitting portion K in a front view. As shown in Figure 8, the formwork body 2 is fitted into the fitting portion K from below at the center of the long side of the formwork body 2, thereby preventing deformation of the two opposing long sides 4A, 4B. The width of the upright pieces 11a of the processed steel material 11 is such that it fits between the ribs 6a, 6a, and in the installed state, the upright pieces 11a, 11a tightly grip and sandwich both sides 4A, 4B of the formwork body 2, thereby effectively preventing deformation of the two opposing long sides 4A, 4B.

[0037] [Other examples of forms] (1) In the above example, the flange pieces, which are divided into several sections by the slit groove 8, are grasped with pliers or the like and peeled off to remove the mold. However, as shown in Figure 9, through holes 13, 13... are formed in each flange piece divided by the slit groove 8, and a rod-shaped member such as a screwdriver is inserted and the pieces are peeled off. (2) With respect to the processed steel material 11, in order to improve the deformation rigidity of the upright pieces 11a, 11a, it is also possible to reinforce the upright pieces 11a so that they do not deform by providing a bracing member 12 on the back surface of the upright pieces 11a, as shown in Figure 10. (3) In the above example of form, an example was described in which a U-shaped rod-shaped steel material 10 was used as the first example of the deformation prevention fitting, but this rod-shaped member 10 is shown in Figure 11 As shown, it is also possible to use a rod-shaped member 10' that is processed into a U-shape. The rod-shaped steel material 10' consists of a relatively large-diameter main body portion 10A' that is processed into a U-shape, and relatively small-diameter fitting pins 10b, 10b that extend from both end faces of the main body portion 10A'. [Explanation of Symbols]

[0038] 1…Resin formwork, 2…Formwork body, 3…Flange, 4A~4D…Side, 5…Bottom, 6(6a・6b)…Rib, 8(8a~8h)…Slit groove, 9(9a・9b)…Cut groove, 10…Rod-shaped steel material (deformation prevention fitting), 11…Processed steel material (deformation prevention fitting)

Claims

1. A resin formwork for a concrete strength test specimen is composed of a resin formwork body having one side as an opening and forming a box shape with four circumferential sides and a bottom surface, and a resin flange portion provided along the circumferential direction to surround the opening of the formwork body, wherein multiple ribs are continuously formed at predetermined intervals on the outer surface of the formwork body, The four circumferential sides consist of two opposing long sides and two opposing short sides, and a deformation prevention fitting is detachably installed to prevent deformation in which the two opposing long sides bulge outward when concrete is filled, so as specified in Japanese Industrial Standard: JIS A1132, the dimensional tolerance of the test specimen is within 0.5% of the cross-sectional width and the angle between the side and bottom of the test specimen is 90 ± 0.5°. The deformation prevention fitting is made of a rod-shaped steel material processed into a U-shape or U-shape, and the rod-shaped steel material is composed of a relatively large-diameter main body portion processed into a U-shape or U-shape, and relatively small-diameter fitting pins extending from both end faces of the main body portion, and through holes are formed in the center of the flange portions on the long sides, and the fitting pins of the rod-shaped steel material are inserted into the through holes to prevent deformation of the two opposing long sides, characterized in that the resin formwork for concrete strength test specimens is provided.

2. The resin formwork for a concrete strength test specimen according to claim 1 is made of ABS resin, polyethylene resin, or polypropylene resin.

3. A resin formwork for a concrete strength test specimen according to either claim 1 or 2, wherein a plurality of slit grooves are formed in the flange portion over a section from the edge of the opening to the outer edge of the flange portion, and a V-shaped thinned cut groove is formed on the outer surface of the formwork body portion over a section from the bottom surface to substantially continuous with the slit grooves.

4. The resin mold for a concrete strength test specimen according to claim 3, wherein the slit groove is formed on the flange portion on the opposing short side of the flange portion.

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