JP2881422B1 - Steel cap for concrete compression test equipment - Google Patents

Abstract

An object of the present invention is to provide a concrete compression test apparatus capable of easily discharging air pockets between a steel cap and a rubber pad, shortening the operation time, and improving the work efficiency of the compression test. . SOLUTION: A steel cap for a concrete compression test device, wherein the steel caps 2A and 2B are formed by engaging a first member 3 and a second member 4 with each other.
Is a cylindrical body having a fitting hole 3a having an inner diameter slightly larger than the outer diameter of the concrete specimen 1. The fitting hole is provided at the lower end side in the axial direction of the annular body through a step. An engaged portion 3b having a diameter larger than that of the engaging portion 3a is formed, includes a step 3c between the engaged portion 3b and the fitting hole 3a, and penetrates from the fitting hole 3a side to the outer peripheral surface 3d. The second member 4 is a substantially disk-shaped member, and is engaged with the engaged portion 3b of the first member 3 on the outer periphery of the circular convex portion 4a formed on the upper surface. The joint portion 4b is formed, and the end surface 4c of the circular convex portion 4a serves as a pressing surface for the concrete specimen 1. The rubber pad 8 is provided on the pressing surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel cap for a compression test apparatus for concrete in which a column-shaped concrete test piece is covered with a steel cap and a pressure test is performed by applying pressure to the test piece. .

[0002]

2. Description of the Related Art When inspecting the strength of concrete used on a highway or the like, the upper and lower end surfaces of a columnar concrete to be tested are finished to be flat by a grinder, and a compressive force is applied by a compression test device. I try to add it. As shown in FIGS. 4 and 5, the concrete compression test apparatus includes a pair of steel caps 12A, 12B and press plates 19A, 19B, and a press mechanism for applying a compressive force to the press plates 19A, 19B. (Not shown). Each of the steel caps 12A and 12B has a circular dish shape and is provided at one end with a fitting recess 12a having an inner diameter adapted to the outer diameter of the concrete specimen 1, and the other flat end faces of the pressing plates 19A and 19B. It is facing. Reference numerals 6 and 6 denote handles fixed to the outer peripheral portion 12b of the steel caps 12A and 12B. When testing the concrete specimen 1 with this compression test apparatus, the rubber pad 8 is held in the fitting recess 12a of each steel cap 12A, 12B, and the upper and lower ends 1a, 1b of the concrete specimen 1 Put on. Then, a compressive force is applied by a pressing mechanism via a pressing plate, and the resistance strength is measured. After the compression test, if dust adheres to the inner surfaces of the steel caps 12A and 12B, an appropriate compression force cannot be applied when the next test piece 1 is tested, and erroneous measurement occurs. For this reason, it is necessary to remove the rubber pad 8 in the fitting recess 12a and sufficiently clean the dust.

[0003]

When the rubber pad 8 used in the above-described concrete compression test apparatus is inserted into the fitting concave portion 12a of the steel caps 12A and 12B, the gap between the bottom surface and the back surface of the rubber pad 8 is formed. In some cases, internal air pockets may occur. If the compression test is performed while the internal air pool remains, the strength value may be significantly lower than the original compression strength test value. Therefore, conventionally, the inside air has been exhausted by inserting the tip of a flathead screwdriver between the inner wall surface of the fitting recess 12a and the outer peripheral edge of the rubber pad 8 to create a gap, and pressing the rubber pad surface with a fingertip. However, such an air discharging operation using a driver is a complicated operation each time a compression test is performed, and requires a long time, so that there is a problem that the operation efficiency is significantly reduced. The present invention
In view of the above problems, a concrete compression test that can easily discharge the internal air between the steel cap and the rubber pad, shortens the working time, and improves the work efficiency of the compression test It is intended to provide a device.

[0004]

In order to achieve the above-mentioned object, the present invention provides a concrete test piece having a cylindrical shape, which is covered with a steel cap on an end face of the test piece. A steel cap for a concrete compression test device for performing a pressure test by adding a first member and a second member, wherein the first member is An annular body having a fitting hole having an inner diameter slightly larger than the outer diameter of the concrete specimen, and having a larger diameter than the fitting hole via a step at one axial end of the annular body. A mating portion is formed, including a step between the engaged portion and the fitting hole, and a small hole penetrating from the fitting hole side to the outer peripheral surface is formed. ,
A substantially disk-shaped body, an engaging portion for engaging with the engaged portion of the first member is formed on an outer periphery of a circular convex portion formed on one surface, and an end surface of the circular convex portion is the concrete specimen. A steel cap for a compression test apparatus for concrete, characterized in that a rubber pad is disposed on the pressure surface.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a concrete compression test apparatus according to the present invention, and FIG.
Is an enlarged view showing a portion II in FIG. 1, and FIG. 3 is a plan view showing a steel cap. The concrete compression test apparatus includes steel caps 2A and 2B that cover both end surfaces 1a and 1b of a concrete specimen 1, and steel caps 2A and 2B.
A pressing mechanism (not shown) for applying a compressive force to the 2B via the pressing plates 9A and 9B is mainly configured. The concrete specimen 1 is a test material of the same material as concrete used for an expressway, and is formed in a columnar shape. The end faces 1a and 1b of the concrete specimen 1 are polished in advance into uneven planes by a polishing apparatus so that a uniform compressive force is applied to both end faces 1a and 1b during a compression test.

The steel caps 2A and 2B are composed of a first member 3 and a second member 4, and are formed using an alloy tool steel material having high wear resistance and excellent rigidity. In addition, rubber lining is applied to the peripheral surface of the steel cap 2 in which two pieces are used as one set to reduce the impact. The first member 3 is an annular body, and has a fitting hole 3a into which the concrete specimen 1 is fitted. The inner diameter of the fitting hole 3a is
The specimen 1 is formed slightly larger than the outer diameter. An engaged portion having a diameter larger than that of the fitting hole 3a is formed at a lower end side in the axial direction of the first member 3 via a step portion 3a. That is, the lower end side opening has a larger diameter than the fitting hole 3a,
A female screw portion (engaged portion) 3b is engraved on the inner peripheral surface. A step 3c is formed between the female screw 3b and the fitting hole 3a. Eight small through-holes 5 are formed between the inner wall surface on the side of the fitting hole 3a including the stepped portion 3c and the outer peripheral surface 3d of the first member 3.
When A and 2B are mounted on the rubber pad 8, the step 3c side and the outer peripheral surface 3d communicate with each other. Reference numeral 3e denotes screw holes engraved at two places on the outer peripheral surface 3d toward the center of the first member 3. A screw portion 6a of a rod-like member is screwed into each screw hole 3e, and a pair of grips 6, 6.

The second member 4 is a substantially disc-shaped body, having a circular convex portion 4a formed on the upper surface, and having a flat lower surface serving as a contact surface of the pressure plate. The outer diameter of the circular projection 4a is
The outer thread is slightly larger than the inner diameter of a, and an outer thread is provided with a male thread (engagement) 4b screwed into the female thread 3b. The end face 4c of the circular projection 4a is connected to the concrete specimen 1
, And a rubber pad 8 is arranged on the pressing surface. The rubber pad 8 is used as a cushioning material, and has an outer diameter substantially equal to the inner diameter of the fitting hole 3a. Also,
The thickness is 10 to 15 mm and the Shore hardness is 50 to 70 degrees, and is set according to the dimensions of the concrete specimen 1. The second member 4 thus formed is the first member 3
The male screw portion 4b of the circular convex portion 4a faces the female screw portion 3b, and a hook of a screwing tool (not shown) is hooked into a hook hole 4e provided on the outer peripheral surface 4d, and screwed together. Integrated. Thereby, the steel caps 2A and 2B are formed in a circular dish shape, and the fitting recess 2a is formed inside.
In the fitting concave portion 2a, the inner opening 5a of the small through hole 5 provided on the side of the step portion 3c faces the end face 4c of the circular convex portion 4a. For this reason, the rubber pad 8 is attached to the end face 4c.
And the inner opening 5a of the small through-hole 5 between the back surface of the rubber pad 8 and the end surface 4c.
Is turned. The pressing plate 9
A and 9B are formed in the shape of a board, two of which are arranged upside down and their outer surfaces are attached to the pressing mechanism.

[0008] When the compression test of the concrete specimen 1 is performed by the concrete compression test apparatus, the rubber pads 8 are held in the steel caps 2A and 2B, respectively. At this time, when the rubber pad 8 is inserted into the fitting recess 2a of the steel caps 2A and 2B, the rubber pad 8 is fitted so that no gap is formed between the rubber pad 8 and the inner peripheral wall.
There is a possibility that air is trapped between the end surface 4c serving as the bottom surface of the rubber pad 8 and the back surface of the rubber pad 8. However, by pressing the center of the rubber pad 8 toward the periphery with a finger, the bottom surface 4c of the fitting recess 2a is formed. The air stagnating between the rubber pad 8 and the back surface is discharged outward through the small through holes 5. These small through holes 5 are provided in the steel caps 2A and 2B with 8 holes.
Since the books are formed uniformly, the air is exhausted without the air remaining in the fitting recess 2a. And both steel caps 2
A, 2B are both end faces 1a, 1b of the concrete specimen 1.
After that, the center of the lower steel plate 2A is aligned with the center of the lower steel plate 2A, and the center of the upper steel plate 2B is further aligned with the center of the upper steel plate 2B.
Adjust the center position of. In this state, a compressive force is applied to the pressing plates 9A and 9B by the pressing mechanism, and the state change at that time is measured.

When the compression test is completed in this manner, the steel plates 2A and 2B are removed from the concrete specimen 1 by separating the pressure plates 9A and 9B, and then the steel plates 2A and 2B are respectively removed. After separating into the first member 3 and the second member 4, the rubber pad 8 is removed and the entire inner peripheral surface is carefully cleaned. After the inside of the fitting recess 2a and the rubber pad 8 are cleaned, the first member 3 and the second member 4 are screwed again, and the rubber pads 8 are attached to the steel caps 2A and 2B in order to perform the next compression test. Should be inserted respectively. As described above, according to the steel cap for the concrete compression test apparatus, the steel caps 2A and 2A are provided.
Since a plurality of small through holes 5 are formed in B, air can be discharged only by pressing the rubber pad 8 with a finger while the rubber pad 8 is mounted on the steel caps 2A and 2B, and the time required to open a gap with a screwdriver or the like is reduced. And work can be shortened. Moreover, since the first member 3 and the second member 4 can be separated, the inner surface can be easily cleaned and the rubber pad can be easily replaced. The steel caps 2A and 2B have a female screw portion 3b as an engaged portion in the opening at one end of the first member 3.
Male screw portion 4b as an engagement portion with circular convex portion 4a of second member 4
However, instead of the female screw portion 3b, a plurality of concave grooves are formed on the inner peripheral surface of the one end side opening, and a convex portion engaged with the concave groove is provided on the outer peripheral portion of the circular convex portion 4a. Accordingly, a structure in which the convex portion is engaged with the concave groove may be adopted. in this case,
If the inner peripheral surface of the one end opening and the outer peripheral portion of the circular convex portion 4a are formed on an inclined surface so that the concave groove and the convex portion are fitted and engaged by a half turn, the engagement between the two is easy. While becoming strong.

[0010]

As described above, according to the present invention, since the small hole penetrating from the fitting hole side including the concave step portion of the first member to the outer peripheral surface is formed, the concrete specimen is formed. Just hold down with your finger before the compression test, and the air pool that has accumulated between the bottom surface of the steel cap and the rubber pad is discharged from the through-hole, so it is necessary to create a gap with a tool such as a screwdriver as in the past. Since the air pockets in the rubber pad can be removed without any trouble, the working time can be shortened and the working efficiency can be improved.

In addition, the first member is an annular body having a fitting hole having an inner diameter slightly larger than the outer diameter of the concrete test piece, and the lower end of the annular body in the axial direction is provided with a stepped portion through the fitting hole. Also, a large diameter engaged portion is formed, and the second member is formed as a substantially disc body, and an engaging portion for engaging with the engaged portion of the first member is formed on the outer periphery of the circular convex portion formed on the upper surface. After completion of the compression test, the engaging member is disengaged from the engaged portion and the second member is removed from the first member, so that the first member becomes an annular body. It is easy to wipe off the end face of the circular convex portion of the second member, which contributes to an accurate compression test. In addition, even when the rubber pad is fitted with a small gap inside the first member, 1 member and 2nd
Since the rubber pad can be removed after detaching the member, the work can be easily performed, and since there is no need to insert a driver or the like at the time of removal, the inner peripheral surface of the first member or the circular convex portion of the second member can be removed. This eliminates the risk of damaging the end face, and contributes to improving the accuracy of the compression test.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a concrete compression test apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a portion II in FIG.

FIG. 3 is a plan view showing a steel cap.

FIG. 4 is a cross-sectional view showing a conventional concrete compression test apparatus.

FIG. 5 is a plan view showing the steel cap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Specimen made of concrete 1a, 1b End face 2A, 2B Steel cap 3 First member 3a Fitting hole 3b Engaged part 3c Step part 3d Outer peripheral surface 4 Second member 4a Circular convex part 4b Engaging part 4c End face 8 Rubber pad

Claims (1)

(57) [Claims] 1. A concrete compression test apparatus for performing a pressure test by covering a steel cap on an end face of a cylindrical concrete specimen and applying pressure to the concrete specimen through the steel cap. The steel cap is formed by engaging a first member and a second member, and the first member has an inner diameter slightly larger than an outer diameter of the concrete specimen. An annular body having a mating hole, wherein an engaged portion having a larger diameter than the fitting hole is formed at a lower end side in the axial direction of the annular body via a step, and A small hole including a step between the holes and penetrating from the fitting hole side to the outer peripheral surface is formed. The second member is a substantially disk-shaped body, and a circular convex portion formed on the upper surface. An engaging portion for engaging with the engaged portion of the first member is formed on the outer periphery of the first member, and an end of the circular convex portion is formed. A steel cap for a compression test apparatus for concrete, characterized in that the surface is a pressing surface against the concrete specimen, and a rubber pad is provided on the pressing surface.