JPS62266461A - Pull-out tester for concrete or the like - Google Patents

Abstract

PURPOSE:To achieve a strength test without damaging concrete, by a method wherein a fixing member is buried into concrete, a means is provided to pull the fixing member and then the fixing member is pulled with a test pin receiving a tension force until the test pin breaks. CONSTITUTION:A pull-out pin 3 is buried into concrete 2 as the fixing member. The pull-out pin 3 and a relay bolt 9 are put together with screws 3a and 9a and the upper end of the relay bolt 9 is connected to a rod 4 through a test pin 7. Then, the rod 4 is pulled upward until the test pin 7 breaks. Here, test pins 7 which are to break by several kinds of tension forces are prepared and a test is performed to guaranteed the minimum strength of the concrete 2 from the breaking strength of the test pin 7. Otherwise, a load gauge is mounted on the rod 4 to perform a test for actual strength in the destruction of the concrete 2 in such a manner as to keep the test pin 7 from breaking. This enables selective testing for guaranteeing minimum strength and for actual strength without destroying concrete.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a fixing member embedded in a concrete frame;
The present invention relates to a pulling test device for concrete, etc., which has a tensioning means capable of applying a pulling force in the direction of pulling out the fixing member.

A drawing test device of the type described above is known. In this type of device, an anchoring member, for example a pull-out pin, is pulled by a pull-out device, and the pulling force of the pull-out device is gradually increased until the concrete breaks. Then, the pull-out load when the concrete 1- is broken is read using a load meter, etc., and the shear strength is determined from this pull-out force and the area of the shear surface of the breaking cone, and the compressive strength of the concrete is estimated from this.

This test has less variation in estimated strength and is said to be more reliable than other test methods, such as the rebound hardness method and the ultrasonic test method. However, as explained above, the requirement is to destroy the concrete.
Therefore, there was a problem that the concrete 1. was damaged.

An object of the present invention is to provide a pull-out test device that enables estimation of compressive strength without damaging a concrete frame.

The present invention solves the above problem by connecting the fixing member and the tensioning means via a test pin, and the test pin is detachable from the fixation member and the tensioning means. The problem was solved by causing the test pin to break by applying a preset tensile force.

When testing the compressive strength of concrete, there are cases in which it is sufficient to ensure that the strength is at least a specified value;
There are times when you want a specific numerical value of the strength. The present invention can be applied to both of the above cases by appropriately selecting the strength of the test pin.

uI Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a tensioning means configured as a jack, la a support base for supporting the jack 1, 2 the concrete frame to be tested, and 3 a fixing member embedded in the concrete frame and configured as a pull-out pin. be. The jack 1 in this embodiment is equipped with a load cell 4a that detects the tensile force and displays it6.
The display by 8 may be by any number of means, such as digitally or by means of a pointer.

As shown in Fig. 2, the rod 4 of the jack 1 has the following:
Legs 5, 6 are integrally formed at their lower ends, and holes 7.8 are provided in the legs 5, 6 in a direction perpendicular to the axis of the rod 4. Note that the width between the legs 5 and 6 is set to be larger than the diameter of a relay bolt, which will be described later.

The pull-out pin 3 is provided with a female threaded portion 3a inside its upper end, and a large-diameter anchor portion 3b at its lower end. A relay bolt 9 having a threaded portion 9a to be screwed thereon is screwed into the □ female threaded portion of the pull-out pin 3, and near the upper end of the relay bolt 9 there is a hole having the same diameter as the holes 7 and 8 and in the same direction. A through hole 10 is provided. And the holes 7, 8
Test pins 11, which are removably attached to the through holes 10, are fitted into these holes.

As shown in FIG. 3, the test pin 11 has two grooves 11a formed on its circumferential surface in this embodiment, and when the test pin 11 is fitted into the holes 7, 8 and 1o, the legs 5 , 6 and the relay bolt 9.

Further, a plurality of test pins 11 are prepared, and the depth of the groove is set in advance so that each test pin 11 is sheared and destroyed by the magnitude of the applied tensile force, which will be described later. In this case, the test pin 11 in this embodiment is in the groove 1.
The magnitude of the tensile force that causes folding changes depending on the depth of 1a. In other words, the strength of the pin is changed, and with this configuration, the diameter of the test pin 11 can be made the same regardless of its strength.

The test method using the pull-out test VL apparatus having the above configuration is performed as follows.

First, a test method for ensuring that the compressive strength of concrete is greater than or equal to a predetermined value will be described.

Test pin 11 having the same strength as the initial strength to be guaranteed
Select. When making this selection, by keeping the material of the pull-out pin 3 and the embedding depth to the anchor part 3b constant, the shear fracture strength can be determined according to the strength of the test pin 11, and then the test pin with the strength that you want to guarantee can be determined. Select. Then, the test pins 11 are set to 150, 180, 21, for example.
0,240.300,360,420,500kg/a
The one that breaks under the tensile force of I, and the one that breaks with an additional 500 kg/
Prepare something that can be bent at aK or higher.

Here, if it is desired to guarantee a minimum concrete strength of 300 kg/cJ, for example, the test pin 11 for 300 kg/cut is used.

During the test, the threaded part 9a of the relay bolt 9 is screwed into the female threaded part 3a of the pull-out pin 3 buried in the concrete frame 2 to be tested, and the relay bolt 9 is connected to the leg 5 of the rod 4.
, 6, the holes 7, 8 of the legs 5, 6 and the through hole 10 are aligned, and the test pin 11 is fitted. Then, a tensile load is applied by the jack 1, and if the test pin 11 breaks due to shear, the compressive strength of the concrete frame 2 becomes 300.
Guaranteed to be at least kg/a7. Furthermore, if the concrete breaks, the pressure gauge 4a detects the tensile load at that time and displays it to the tester.

Next, if you want to obtain the numerical value of the compressive strength of the concrete frame 2, use the strongest test pin 11 of, for example, 500 kg/(211 or more. Then, if you perform the test in the same manner as above, the test pin 11 will be The concrete breaks in a cone shape without shear failure, and the compressive strength of the concrete frame 2 can be estimated from the magnitude of the tensile load at that time and the shear area of the concrete cone.

In this way, the strength of the concrete frame is tested, and depending on the tester's wishes, the tester can choose to guarantee the minimum strength of the concrete frame or obtain the actual value, and if the minimum strength is guaranteed, the concrete frame will not be damaged. It can be done without.

Note that the internal dimension between the supporting points of the support base 1a shown in FIG. 1 is at least four times the embedding depth of the pull-out pin 3.

Further, the material of the test pin 11 is not limited in any way as long as it is homogeneous.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, the test pin 11 may have the shape shown in FIGS. 4(a) and 4(b), or may have a pin diameter that changes depending on the strength as shown in FIG. 4(c). Also,
The fixing member may be integrated with the relay pin. Further, as the tensioning means, any suitable tensioning means can be used as long as it can tension the rod, such as a hydraulic pump.

Although the above-mentioned embodiment is a pull-out test device that breaks the test pin 11 by shearing, the present invention can also be applied to a device that breaks the test pin by tension, which will be explained below.

In FIG. 5, reference numeral 24 is a rod of the jack 1 (not shown), and 29 is a relay bolt screwed onto a pull-out pin 23 buried in the concrete body 22. At the mutually opposing ends of the rod 24 and the relay bolt 29, claws 2 are provided.
7 and 28 are provided respectively, and the test pin 31 is removably fitted into the claws 27 and 28 from the horizontal direction. Test pin 3
1, as clearly shown in FIG. 6, large diameter portions 31b are formed at both ends and a small diameter portion 31a is formed in the central region. In this case, the large diameter portion 31b is set to a predetermined size so as to be fitted with the pawls 27.28, but the small diameter portion 31a is set to a predetermined size so as to fit with the claws 27. The size of the diameter is set in advance so that the tensile fracture occurs according to the amount of stress.

By preparing a large number of test pins 31 that can be tensile broken at a predetermined strength, the pull-out test device having the above structure can be used to ensure that the compressive strength of concrete is equal to or higher than a predetermined value, similar to the embodiment described above. test is obtained and also e.g. 50
If the strongest test pin 31 of 0 kg/(d or more is used), a test can be obtained in which the compressive strength of the concrete frame 22 can be estimated from the magnitude of the tensile load and the shear area of the concrete cone.

The test pin 31 may have a V-groove 31a as shown in FIG. 7, or may have a groove of various shapes such as a U-groove in the center, or may have a different pin diameter.

Effects The pull-out test device according to the present invention is configured as described above, and can be selected for tests that guarantee the minimum strength of concrete, etc. and tests that obtain actual strength values, and can be conducted without damaging the concrete in the test that guarantees the minimum strength.

Note that the present invention can also be applied to an anchor pullout test.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a schematic diagram showing an embodiment of the present invention.
FIG. 3 is a perspective view showing the test pin; FIGS. 4(a), (b), and (c) are perspective views showing modified examples of the test pin; FIG. 5 is a perspective view showing a modified example of the test pin; 6 is a perspective view showing a test pin used in the embodiment shown in FIG. 5; FIG. 7 is a perspective view of a test pin used in the embodiment shown in FIG. 5. It is a perspective view showing a modification. 1... Jacket 2.22... Concrete frame 3.23... Pull-out pin 11.31... Test pin 11a lla 1l (C1). (b), 1

Claims (2)

[Claims] (1) In a pull-out testing device for concrete, etc., which has a fixing member embedded in a concrete frame and a tensioning means capable of applying a tensile force in the direction of pulling out the fixing member, the fixing member and the tensioning means are The above-mentioned pull-out test device is connected via a test pin, the test pin is detachable from the fixing member and the tensioning means, and the test pin is broken by applying a preset tensile force. . (2) freely changing the set value of the tensile force that causes the test pin to break by changing the diameter of the test pin or by changing at least one factor of the width and depth of the groove formed in the test pin; The above-mentioned pull-out test device.