Test piece forming device for fiber-cement oblique pull-out performance test

Abstract

The utility model discloses a test piece forming device for a fiber-cement slant pull-out performance test, which comprises a switch type magnetic base, a bottom plate, a pair of side fasteners, a bolt short rod, a middle fastener and a single fiber, the bottom plate is made of non-metal materials, the switch type magnetic base is arranged on the back of the bottom plate, and the bolt short rod is arranged on the back of the bottom plate. The pair of side fasteners are fixed on two sides of the front surface of the bottom plate through the bolt short rods, the middle fastener is divided into an upper layer and a lower layer, the upper layer of middle fastener and the lower layer of middle fastener are overlapped together and are horizontally arranged between the pair of side fasteners at any angle, the two bolt short rods are connected with two ends of the fiber, and the fiber is horizontally arranged between the upper layer of middle fastener and the lower layer of middle fastener. The device is novel in structure and convenient to use, the pre-embedded fiber can present different angles with the base body according to needs, the mechanical property of the single fiber during oblique pulling-out can be accurately measured, and a scientific basis is provided for material design and engineering application of a high-ductility fiber reinforced composite material.

Description

Technical Field

[0001] The utility model belongs to the technical field of processing equipment for high-ductility fiber-reinforced cement-based composite materials, and particularly relates to a test piece forming device for testing the oblique pull-out performance of fiber-cement. Background Art

[0002] In civil engineering, fiber-reinforced composites (FRPs) are widely used in various structures due to their superior crack resistance and durability. In particular, the introduction of fibers into a cement matrix not only effectively improves the material's tensile strength but also inhibits crack propagation. Therefore, the interfacial bonding between the fiber and the matrix plays a key role in the overall mechanical properties of FRPs. Research on the pullout properties of single fibers is crucial.

[0003] Existing single-fiber pullout performance testing methods mostly focus on situations where the fiber is subjected to perpendicular forces relative to the matrix. However, in actual engineering, fibers are often subjected to oblique pullout forces. However, most existing test devices and specimen designs cannot accurately simulate the oblique forces on the fibers in the cement matrix. Existing mold designs are also mostly used for fixed-angle fiber pullout tests, and cannot flexibly adjust the fiber embedding angle, making them unable to adapt to testing requirements for various oblique forces. Utility Model Content

[0004] To solve the above problems, the utility model discloses a specimen forming device for testing the oblique pull-out performance of fiber-cement. The device has a novel structure and is easy to use. It can allow the embedded fibers to present different angles with the matrix as needed, and can accurately measure the mechanical properties of a single fiber during oblique pull-out, providing a scientific basis for the material design and engineering application of high-ductility fiber-reinforced composite materials.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present utility model is as follows:

[0006] A test specimen forming device for testing the oblique pull-out performance of fiber-cement includes a switchable magnetic base, a base plate, a pair of side fasteners, a bolt short rod, an intermediate fastener, and a single fiber. The base plate is made of non-metallic material, the switchable magnetic base is arranged on the back side of the base plate, the pair of side fasteners are fixed to both sides of the front side of the base plate by bolt short rods, the intermediate fastener is divided into two layers, the upper and lower layers of intermediate fasteners are superimposed together, and are horizontally arranged at any angle between the pair of side fasteners (the distance between the pair of side fasteners is greater than the diagonal length of the intermediate fastener to facilitate free rotation of the intermediate fastener therein), two bolt short rods connect the two ends of the fiber, and the fiber is horizontally arranged between the upper and lower layers of intermediate fasteners.

[0007] Specifically, the switchable magnetic base has dimensions of 116 mm in length, 50 mm in width, and 55 mm in height, and is used to fix the relative positions of the intermediate fasteners.

[0008] Specifically, the bottom plate is made of acrylic material with a thickness of ≤2 cm, which can fully transmit magnetic force and thus fix the intermediate fastener.

[0009] Specifically, the pair of side fasteners have the same size and thickness as the lower layer middle fastener.

[0010] Specifically, the intermediate fastener is a pair of hollow square iron blocks stacked up and down, which are fixed to the base plate through a switch-type magnetic base. Through the free rotation and fixation of the intermediate fastener, different angles between the fiber and the cement matrix can be adjusted to adapt to oblique pull-out tests at different angles.

[0011] The beneficial effects of the utility model are:

[0012] The processing device proposed in the utility model is used to prepare a test piece for testing the oblique pull-out performance of fiber-cement. Through the free rotation and fixation of the cement-based material forming template, the pre-embedded inclination angle of the single fiber of the test piece can be changed. The processed test piece can realize the oblique pull-out of the single fiber, providing a scientific basis for the material design and engineering application of high-ductility fiber-reinforced composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0014] Figure 2 This is a schematic diagram of the split structure of the utility model;

[0015] Figure 3 It is a three-dimensional schematic diagram of the test piece described in the utility model;

[0016] Figure 4 This is a schematic diagram (cross-sectional view) of the weakened surface of the specimen described in the present invention.

[0017] List of Figure Symbols:

[0018] 1. Switchable magnetic base; 2. Bottom plate; 3. Side fasteners; 4. Bolt short rod; 5. Middle fastener; 6. Fiber. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0020] The fiber-cement oblique pull-out performance test piece described in the present invention is as follows: Figure 3 and 4 As shown, its appearance is a prism, with a single fiber 6 embedded and fixed in the middle. The fiber is fixed at the geometric center of the specimen, and the angle of the embedded fiber is adjusted by this device (as needed).

[0021] This embodiment provides a test piece forming device for testing the oblique pull-out performance of fiber-cement. Figure 1 and 2 As shown, it includes a switchable magnetic base 1, a base plate 2, a pair of side fasteners 3, a bolt short rod 4 and two upper and lower intermediate fasteners 5, wherein the base plate 2 is made of non-metallic material, the switchable magnetic base 1 is arranged on the back of the base plate 2, a pair of side fasteners 3 are fixed to both sides of the front of the base plate 2 by bolt short rods 4, the two intermediate fasteners 5 are overlapped up and down and arranged between the pair of side fasteners 3, the two bolt short rods 4 connect the two ends of the fiber 6, and the fiber 6 is horizontally arranged between the upper and lower layers of intermediate fasteners 5.

[0022] Specifically, the switchable magnetic base 1 has dimensions of 116 mm in length, 50 mm in width, and 55 mm in height, and is used to fix the relative position of the intermediate fastener 5 .

[0023] Specifically, the bottom plate 2 is made of acrylic or other non-magnetic materials, which can fully transmit magnetic force to fix the intermediate fastener 5.

[0024] Specifically, the pair of side fasteners 3 have the same size and thickness as the lower layer middle fastener.

[0025] Specifically, the intermediate fastener 5 is a pair of hollow square iron blocks stacked up and down, fixed to the base plate 2 through a switch-type magnetic base 1. The diagonal length of the intermediate fastener 5 is less than the distance between the two side fasteners 3, so that the intermediate fastener can freely rotate at any angle therein. Through the free rotation and fixation of the intermediate fastener 5, different angles between the fiber and the cement matrix can be adjusted to adapt to oblique pull-out tests at different angles.

[0026] To use, place the switchable magnetic base 1 under the base plate 2, place the side fasteners 3 relatively parallel to the base plate 2, and secure them with bolt short rods 4. Then, place the lower middle fastener and adjust its angle. Open the magnetic base 1, fix the position of the lower middle fastener, wrap the ends of the fiber 6 around the two side fasteners, and stack the other (upper) middle fastener and secure it with the magnetic base.

[0027] After evenly applying the release agent to the inner wall of the middle fastener, pour the cement-based material into the mold and vibrate it thoroughly. After forming, cover it with plastic film, keep the surface moist, and let it stand for 1 to 2 days.

[0028] The mold was removed, and each component was cleaned and dried. The prepared specimen was placed in a standard curing room with a temperature of 20°C ± 2°C and a relative humidity of ≥ 95% for curing for 28 days to obtain the final test specimen.

[0029] Through this device, the embedded fiber can be made to present different angles with the matrix as needed, so as to accurately measure the mechanical properties of a single fiber when it is pulled out obliquely. It has a novel structure, is easy to use, and is worthy of promotion.

[0030] It should be noted that the above content only illustrates the technical idea of ​​the utility model and cannot be used to limit the protection scope of the utility model. For ordinary technicians in this technical field, they can make several improvements and modifications without departing from the principles of the utility model. These improvements and modifications all fall within the protection scope of the claims of the utility model.

Claims

1. A fiber-cement oblique pull-out performance test specimen forming device, characterized by: The invention comprises a switch-type magnetic base (1), a base plate (2), a pair of side fasteners (3), a bolt short rod (4) and two layers of upper and lower intermediate fasteners (5), wherein the base plate (2) is made of non-metallic material, the switch-type magnetic base (1) is arranged on the back of the base plate (2), the pair of side fasteners (3) are fixed to both sides of the front of the base plate (2) through the bolt short rod (4), the two intermediate fasteners (5) are superimposed on each other and arranged between the pair of side fasteners (3), the two bolt short rods (4) connect the two ends of the fiber (6), and the fiber (6) is horizontally arranged between the upper and lower layers of the intermediate fasteners (5).

2. The fiber-cement oblique pull-out performance test specimen forming device according to claim 1, characterized in that: The switch-type magnetic base (1) has dimensions of 116 mm in length, 50 mm in width, and 55 mm in height, and is used to fix the relative position of the intermediate fastener (5).

3. The fiber-cement oblique pull-out performance test specimen forming device according to claim 1, characterized in that: The bottom plate (2) is made of acrylic material and can fully transmit magnetic force to fix the intermediate fastener (5).

4. The fiber-cement oblique pull-out performance test specimen forming device according to claim 1, characterized in that: The pair of side fasteners (3) have the same size and thickness as the lower layer middle fastener.

5. The fiber-cement oblique pull-out performance test specimen forming device according to claim 1, characterized in that: The intermediate fasteners (5) are a pair of hollow square iron blocks stacked one above the other, fixed to the base plate (2) via a switchable magnetic base (1). By freely rotating and fixing the intermediate fasteners (5), different angles between the fiber and the cement matrix can be adjusted to accommodate oblique pull-out tests at different angles.

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