CN115753425A - An adjustable deflection test device suitable for flexural toughness test of fiber-reinforced concrete - Google Patents

Abstract

An adjustable deflection testing device suitable for a fiber concrete bending toughness test comprises two semi-rectangular vertical supports, two supports, a plurality of connecting screws, two limiting angle steels, a plurality of control screws, a plurality of quasi-point screws and a piece to be tested; the invention can solve the problems that the part of the device which is used for fixing the midspan deflection test instrument in the existing standard cannot be flexibly moved and is not suitable for deflection test instruments with different sizes and specifications. The invention can conveniently and flexibly fix deflection test instruments of different types and specifications, ensures accurate measurement of the net deflection of the span, does not include the shearing or twisting influence of the test sample on the bracket of the test sample, and can be repeatedly used. The defect that through holes capable of clamping the instrument are reserved after the type of the instrument needs to be known in advance in the existing support for fixing the midspan deflection testing instrument is effectively overcome.

Description

An adjustable deflection test device suitable for flexural toughness test of fiber-reinforced concrete

technical field

The invention belongs to the field of performance testing of concrete materials, and relates to an adjustable deflection testing device suitable for fiber concrete bending toughness testing.

Background technique

Concrete has been widely used since its birth because of its high compressive strength, easy molding, and convenient material acquisition. It is the main building material. However, concrete materials have low tensile strength and poor toughness, and brittle failure usually occurs under load, and as the strength of concrete increases, its brittleness increases significantly; concrete structures are inevitably damaged during use or even during construction. Cracks will occur, and then further crack and expand under the influence of various factors, shortening the life of the structure and causing safety hazards. Scholars at home and abroad generally believe that an effective measure to improve the crack resistance and toughness of concrete is to use fiber reinforcement. Fiber concrete is based on cement slurry, mortar or concrete, and is made of metal fibers, inorganic non-metallic fibers, synthetic fibers or natural organic fibers. In order to strengthen the composite material composed of materials, the fiber added to the concrete can prevent the generation and development of cracks inside the concrete, and can significantly improve the tensile, bending, impact and fatigue resistance of the concrete. It has been widely used in engineering construction. field.

The flexural toughness can reflect the flexural strength and energy dissipation capacity of fiber reinforced concrete beams under the action of lateral force, and is an important index to measure the toughness of fiber reinforced concrete. The more commonly used methods of flexural toughness evaluation in the world include: ASTMC1-48 standard, RILEMTC162-TDF flexural toughness evaluation method, JSCE-SF4 standard, DBV1998 standard, etc. These standards need to be evaluated by calculating the area under the load-deflection curve of the beam The toughness of fiber-reinforced concrete is usually tested using a four-point bending beam test using three-point loading.

It can be seen from the literature and specifications that in order to obtain the load-deflection curve of the beam accurately, in the deflection test device used for the flexural toughness test of fiber concrete, the position of the deflection test device such as electronic sensor or electronic deflection meter should ensure accurate determination of the net deflection of the mid-span , excluding the effects of shear or torsion of the specimen on its support. One acceptable arrangement is to use a rectangular fixture that encloses the specimen and clamps it at mid-depth just above the support, with two displacement gauges mounted on the midspan fixture for midspan deflection on each side One, the average of its measurements represents the net deflection. However, the existing brackets for fixing mid-span deflection testing instruments need to reserve a through hole for clamping the instrument after knowing the type of the instrument in advance, and cannot move flexibly, and are not suitable for deflection testing instruments of different sizes and specifications.

Contents of the invention

The present invention proposes an adjustable deflection testing device suitable for flexural toughness test of fiber concrete, which includes two semi-rectangular vertical supports, two brackets, several connecting screws, two limit angle steels, several control screws, several punctual screws and to be tested.

The semi-rectangular vertical support is a frame structure with an opening facing downwards, including beams and columns, and a rectangular cavity is formed in the frame.

The semi-rectangular vertically supported beam is provided with a first threaded hole matching with a control screw.

The semi-rectangular vertically supported column is provided with a second threaded hole matched with a point screw.

The bracket is a rectangular plate as a whole, the plate end extends out of the variable section platform, and the other end is provided with a third threaded hole.

The middle part of the bracket is provided with a slide rail.

The top end of the connecting screw is provided with a sliding part matching the slide rail of the bracket.

The limiting angle steel is an L-shaped angle steel composed of two square plates, and one of the square plates is provided with a fourth threaded hole matching with a connecting screw.

The test piece is a cuboid test piece. The two brackets are attached to both lateral sides of the test piece. The semi-rectangular vertical support straddles the longitudinal ends of the test piece to clamp the support.

When working, fix the test piece in the rectangular cavity supported by two semi-rectangular vertical supports. The two semi-rectangular vertical supports are fixed on the test piece by the punctual screw, the second threaded hole of one semi-rectangular vertical support is respectively connected with the third threaded holes of the two brackets through the punctual screw, and the other semi-rectangular vertical The second threaded holes of the support are respectively connected with the variable-section platforms of the two brackets through punctual screws; one end of the connecting screw provided with a sliding part is built into the slide rail of the bracket; the connecting screw fixes the limit angle steel on the bracket Above; the limit angle steel is used to fix the deflection test displacement meter through the slide rail.

Further, the bracket is also provided with a through hole for fixing the auxiliary limit angle steel to fix the displacement meter for the deflection test.

The through holes for fixing are located on both sides of the slide rail and distributed symmetrically along the central axis of the bracket.

Further, the size of the variable-section platform is greater than twice the diameter of the overlapping screw.

Further, the variable section platform is an angled variable section set at both ends of the platform with twice the diameter of the screw.

Further, the groove of the slide rail is a rectangular groove, a trapezoidal groove, a dovetail groove or a T-shaped groove.

Further, the control screw is used to adjust the vertical height of the semi-rectangular vertical support, so that the quasi-point screw is aligned with the intersection of the two-point support device at the bottom of the bending test along the line of action of the cross-section of the specimen and the central axis of the longitudinal section of the specimen to be tested, Furthermore, it is realized that the bracket is positioned at the central axis of the longitudinal section of the test piece.

Further, the material of the semi-rectangular vertical supports and brackets is steel, aluminum alloy or iron.

The technical effect of the present invention is undoubted, and the present invention can solve the problem that the part used to fix the mid-span deflection test instrument in the device mentioned in the existing specification cannot be flexibly moved, and is not suitable for deflection test instruments of different sizes and specifications. The invention can conveniently and flexibly fix deflection testing instruments of different types and specifications, ensure accurate measurement of mid-span net deflection, does not include shearing or torsion effects of the sample on its support, and can be used repeatedly. It effectively solves the disadvantage that the existing bracket used for fixing the mid-span deflection test instrument needs to know the type of the instrument in advance and reserve a through hole for clamping the instrument.

Description of drawings

Fig. 1 is the overall schematic diagram that the adjustable deflection testing device provided by the present invention is used for bending test;

Fig. 2 is a schematic diagram of a semi-rectangular vertical support structure;

Fig. 3 is the schematic diagram of support structure;

Figure 4 is a partially enlarged view of the slide rail in the bracket;

In the figure: semi-rectangular vertical support 1, first threaded hole 1-1, second threaded hole 1-2, rectangular cavity 1-3, beam 1-4, column 1-5, bracket 2, third threaded hole 2-1, variable section platform 2-2, slide rail 2-3, through hole for fixing 2-4, connecting screw 3, sliding part 3-1, limit angle steel 4, fourth threaded hole 4-1, control screw 5. Punctual screw 6. Test piece 7.

Detailed ways

The present invention will be further described below in conjunction with the examples, but it should not be understood that the scope of the subject of the present invention is limited to the following examples. Without departing from the above-mentioned technical ideas of the present invention, various replacements and changes made according to common technical knowledge and conventional means in this field shall be included in the protection scope of the present invention.

Example 1:

Referring to Fig. 1 to Fig. 4, this embodiment discloses an adjustable deflection test device suitable for flexural toughness test of fiber concrete, including two semi-rectangular vertical supports 1, two brackets 2, several connecting screws 3, two limiting Bit angle steel 4, several control screw rods 5, several punctual screw rods 6 and a test piece 7.

The semi-rectangular vertical support 1 is a frame structure with an opening facing downwards, including beams 1-4 and columns 1-5, and a rectangular cavity 1-3 is formed in the frame.

The number of the semi-rectangular vertical support 1 is 2, arranged on both sides of the test piece, the spacing is equal to the distance (300mm or 450mm) between the two support points of the test bottom support device, depending on the size of the test piece .

The beam 1 - 4 of the semi-rectangular vertical support 1 is provided with a first threaded hole 1 - 1 matching with a control screw 5 .

The upright column 1-5 of the semi-rectangular vertical support 1 is provided with a second threaded hole 1-2 matching with the alignment screw 6 .

The bracket 2 is a rectangular plate as a whole, the variable section platform 2-2 extends from the end of the plate, and a third threaded hole 2-1 is provided at the other end.

The middle part of the support 2 is provided with a slide rail 2-3.

The top end of the connecting screw 3 is provided with a sliding part 3 - 1 matching the slide rail 2 - 3 of the bracket 2 .

The limiting angle steel 4 is an L-shaped angle steel composed of two square plates, and one of the square plates is provided with a fourth threaded hole 4-1 matching the connecting screw 3.

The test piece 7 is a cuboid test piece. The two brackets 2 are attached to both lateral sides of the test piece 7 . The semi-rectangular vertical support 1 straddles the longitudinal ends of the test piece 7 and clamps the bracket 2 .

The semi-rectangular vertical supports 1 are arranged along the cross-sectional direction of the test piece and located at both ends of the test piece. The support 2 is located on the longitudinal section of the test piece, distributed along the central axis of the test piece.

During operation, the test piece 7 is fixed in the rectangular cavities 1-3 of the two semi-rectangular vertical supports 1 . Two semi-rectangular vertical supports 1 are fixed on the object to be tested by the punctual screw 6, wherein the second threaded hole 1-2 of one semi-rectangular vertical support 1 is connected with the third threaded hole 2-1 of the two brackets 2 respectively The second threaded hole 1 - 2 of the other semi-rectangular vertical support 1 is connected with the variable-section platforms 2 - 2 of the two brackets 2 through the punctual screw 6 . One end of the connecting screw 3 provided with the sliding part 3 - 1 is built into the slide rail 2 - 3 of the bracket 2 . The connecting screw 3 fixes the limit angle steel 4 on the bracket 2 . The limit angle steel 4 fixes the deflection test displacement gauge through the slide rail 2-3.

The bracket 2 is also provided with a through hole 2-4 for fixing the auxiliary limit angle steel 4 to fix the displacement meter of the deflection test.

The through holes 2-4 for fixing are located on both sides of the slide rail 2-3, and are distributed symmetrically along the central axis of the bracket 2.

The size of the variable cross-section platform is greater than twice the diameter of the lap screw.

The variable section platform is an angled variable section arranged at both ends of the platform with twice the diameter of the screw.

The grooves of the slide rails 2-3 are rectangular grooves, trapezoidal grooves, dovetail grooves or T-shaped grooves.

The control screw 5 is used to adjust the vertical height of the semi-rectangular vertical support 1, so that the quasi-point screw 6 is aligned with the intersection of the two-point support device at the bottom of the bending test along the line of action of the cross-section of the test piece and the central axis of the longitudinal section of the test piece , so as to realize the positioning of the bracket 2 at the central axis of the longitudinal section of the test piece.

The semi-rectangular vertical support 1 and bracket 2 are made of steel, aluminum alloy or iron to ensure a certain rigidity of the testing device.

The adjustable deflection test device is applicable to the three-point and four-point bending test loading methods involved in the existing fiber concrete bending toughness evaluation specification.

Example 2:

Referring to Fig. 1 to Fig. 4, this embodiment discloses an adjustable deflection test device suitable for flexural toughness test of fiber concrete, including two semi-rectangular vertical supports 1, two brackets 2, several connecting screws 3, two limiting Bit angle steel 4, several control screw rods 5, several punctual screw rods 6 and a test piece 7.

The semi-rectangular vertical support 1 is a frame structure with an opening facing downwards, including beams 1-4 and columns 1-5, and a rectangular cavity 1-3 is formed in the frame.

The number of the semi-rectangular vertical support 1 is 2, arranged on both sides of the test piece, the spacing is equal to the distance (300mm or 450mm) between the two support points of the test bottom support device, depending on the size of the test piece .

The beam 1 - 4 of the semi-rectangular vertical support 1 is provided with a first threaded hole 1 - 1 matching with a control screw 5 .

The upright column 1-5 of the semi-rectangular vertical support 1 is provided with a second threaded hole 1-2 matching with the alignment screw 6 .

The bracket 2 is a rectangular plate as a whole, the variable section platform 2-2 extends from the end of the plate, and a third threaded hole 2-1 is provided at the other end.

The middle part of the support 2 is provided with a slide rail 2-3.

The top end of the connecting screw 3 is provided with a sliding part 3 - 1 matching the slide rail 2 - 3 of the bracket 2 .

The limiting angle steel 4 is an L-shaped angle steel composed of two square plates, and one of the square plates is provided with a fourth threaded hole 4-1 matching the connecting screw 3.

The test piece 7 is a cuboid test piece. The two brackets 2 are attached to both lateral sides of the test piece 7 . The semi-rectangular vertical support 1 straddles the longitudinal ends of the test piece 7 and clamps the bracket 2 .

The semi-rectangular vertical supports 1 are arranged along the cross-sectional direction of the test piece and located at both ends of the test piece. The support 2 is located on the longitudinal section of the test piece, distributed along the central axis of the test piece.

During operation, the test piece 7 is fixed in the rectangular cavities 1-3 of the two semi-rectangular vertical supports 1 . Two semi-rectangular vertical supports 1 are fixed on the object to be tested by the punctual screw 6, wherein the second threaded hole 1-2 of one semi-rectangular vertical support 1 is connected with the third threaded hole 2-1 of the two brackets 2 respectively The second threaded hole 1 - 2 of the other semi-rectangular vertical support 1 is connected with the variable-section platforms 2 - 2 of the two brackets 2 through the punctual screw 6 . One end of the connecting screw 3 provided with the sliding part 3 - 1 is built into the slide rail 2 - 3 of the bracket 2 . The connecting screw 3 fixes the limit angle steel 4 on the bracket 2 . The limit angle steel 4 fixes the deflection test displacement gauge through the slide rail 2-3.

Example 3:

The main structure of this embodiment is the same as that of Embodiment 2, and the bracket 2 is also provided with an auxiliary limit angle steel 4 for fixing the through-hole 2-4 for fixing the deflection test displacement gauge.

The through holes 2-4 for fixing are located on both sides of the slide rail 2-3, and are distributed symmetrically along the central axis of the bracket 2.

Example 4:

The main structure of this embodiment is the same as that of Embodiment 2, and the size of the variable cross-section platform is greater than twice the diameter of the lap screw.

Example 5:

The main structure of this embodiment is the same as that of Embodiment 2, and the variable cross-section platform is provided with an angled variable cross-section at both ends of the platform with twice the diameter of the screw.

Embodiment 6:

The main structure of this embodiment is the same as that of Embodiment 2, and the grooves of the slide rails 2-3 are rectangular grooves, trapezoidal grooves, dovetail grooves or T-shaped grooves.

Embodiment 7:

The main structure of this embodiment is the same as that of Embodiment 2. The control screw 5 is used to adjust the vertical height of the semi-rectangular vertical support 1, so that the punctual screw 6 is aligned with the two-point support device at the bottom of the bending test along the line of action of the cross-section of the specimen. The intersection point with the central axis of the longitudinal section of the test piece, thereby realizing the positioning of the bracket 2 at the central axis of the longitudinal section of the test piece.

Embodiment 8:

The main structure of this embodiment is the same as that of Embodiment 2, and the material of the semi-rectangular vertical support 1 and bracket 2 is steel, aluminum alloy or iron to ensure that the test device has a certain rigidity.

The adjustable deflection test device is applicable to the three-point and four-point bending test loading methods involved in the existing fiber concrete bending toughness evaluation specification.

Embodiment 9:

Referring to Fig. 1 to Fig. 4, an adjustable deflection test device suitable for flexural toughness test of fiber concrete mainly includes semi-rectangular vertical support 1, bracket 2, slide rail 2-3, limit angle steel 4 and through hole 2 for fixing -4;

The upper part of the semi-rectangular vertical support 1 is provided with two threaded holes 1-1 and matching control screw rods 5, and the left and right sides are provided with threaded holes 1-2 and matching punctual screw rods 6;

The middle part of the support 2 is slotted and embedded into the slide rail 2-3, the limit angle steel 4 is installed on the slide rail 2-3, and the left side of the support 2 is provided with a threaded hole 2-1, and the right side is provided with a variable section platform 2- 2;

The limiting angle steel 4 is provided with a threaded hole 4-1 matching the connecting screw 3 used for connecting the slide rail 2-3;

The fixing through holes 2-4 are located at the upper and lower parts of the slide rail 2-3, and are symmetrically distributed along the central axis of the bracket 2;

The semi-rectangular vertical support 1 is arranged along the cross-sectional direction of the test piece, and is located at both ends of the test piece;

The support 2 is located on the longitudinal section of the test piece and distributed along its central axis;

The threaded hole 4-1 on the limit angle steel 4 is connected by the matching connecting screw 3 on the slide rail 2-3, so as to realize the movement of the limit angle steel 4 on the slide rail 2-3;

The fixing through hole 2-4 is used for auxiliary limit angle steel 4 to fix the deflection test displacement meter;

During assembly, the threaded hole 2-1 on the left side of the bracket 2 is aligned with the threaded hole 1-2 on the side of the semi-rectangular vertical support 1, and connected with the point screw 6; the variable-section platform 2-2 on the right side of the bracket 2 is lapped on the Pass on the quasi-point screw 6 of the semi-rectangular vertical support 1 side threaded hole 1-2 on the right side of the test piece.

The semi-rectangular vertical support 1 adjusts the vertical height with the control screw 5, so that the two-point point screws 6 on both sides are aligned with the intersection of the two-point support device at the bottom of the bending test along the cross-section action line of the test piece and the central axis of the longitudinal section of the test piece, In order to realize the positioning of the bracket 2 at the clear span range of the test piece along the central axis of the longitudinal section of the test piece.

The adjustable deflection test device is applicable to the three-point and four-point bending test loading methods involved in the existing fiber concrete bending toughness evaluation specification.

The number of the semi-rectangular vertical support 1 is 2, arranged on both sides of the test piece, the spacing is equal to the distance (300mm or 450mm) between the two support points of the test bottom support device, depending on the size of the test piece .

The semi-rectangular vertical support 1 and bracket 2 are made of steel, aluminum alloy or iron to ensure the test device has a certain rigidity.

Example 10:

Referring to Figures 1 to 4, an adjustable deflection testing device. The device is provided with two semi-rectangular vertical supports and two brackets for fixing the mid-span deflection tester. Both the upper part and the side of the semi-rectangular vertical support are provided with threaded holes, which are used for positioning with a screw rod and fixing the bracket in the middle part of the longitudinal section of the test piece.

The semi-rectangular vertical support should be arranged in a surrounding shape along the cross-section of the test piece, and its axis is aligned with the line of action between the support of the two-point support device at the bottom of the test piece and the contact surface of the test piece, so as to ensure the self-weight of the deflection test device Transfer to the support; the threaded holes on both sides of the semi-rectangular vertical support should be aligned with the intersection of the central axis of the longitudinal section of the test piece and the action point of the bottom support along the action line of the cross section of the test piece.

The middle part of the bracket is slotted and embedded into the slide rail, and the limit angle steel is installed on the slide rail, and there are through holes symmetrically distributed on the upper and lower parts of the slide rail along the central axis of the bracket, which are used to assist the limit angle steel to perform the deflection test on the displacement meter. Fixed; there is a threaded hole on the left side of the bracket, and a variable-section platform on the right side; the threaded hole on the left side of the bracket is consistent with the threaded hole on the side of the semi-rectangular vertical support, and the variable-section platform on the right is lapped and passed through the position to be tested The semi-rectangular vertical support on the right side of the part is on the threaded rod of the side threaded hole.

The limit angle steel is provided with a threaded hole matching the screw rod used for connecting the slide rail, and is connected through the matching screw rod on the slide rail to realize the movement of the limit angle steel on the slide rail.

The size of the variable cross-section platform on the right side of the bracket can be larger than twice the diameter of the overlapping screw rod, leading to the right end of the bracket along the variable cross section, or it can be set as an angled variable cross section at both ends of the platform twice the diameter of the screw rod.

The platform on the right side of the bracket and the center of the threaded hole on the left side should be kept at the same level, that is, on the central axis of the bracket.

The two limit angles on the slide rail should ensure that the deflection testing equipment is located at the mid-span of the specimen to accurately obtain the mid-span deflection.

Example 11:

Please refer to Fig. 1 to Fig. 4, the adjustable deflection test device provided by the embodiment of the present invention includes two semi-rectangular vertical supports 1 and two supports 2, and the two semi-rectangular vertical supports 1 are used to connect the two supports 2 Positioned at the central axis of the longitudinal section of the test piece; the upper part of the semi-rectangular vertical support 1 is provided with two threaded holes 1-1 and a matching control screw 5, and the left and right sides are provided with threaded holes 1-2 and Matching punctual screw rod 6; slotted in the middle of the bracket 2 and embedded in the slide rail 2-3, the limit angle steel 4 is installed on the slide rail 2-3, and a threaded hole 2-1 is provided on the left side of the bracket 2, and the right side A variable cross-section platform 2-2 is provided; two limit angle steels 4 are used to position the mid-span deflection tester, and two limit angle steels 4 are provided with two connecting screw rods 3 that match the connecting slide rails 2-3. Threaded hole 4-1; located on the upper and lower parts of the slide rail 2-3, there are four fixed through holes 2-4 symmetrically distributed along the central axis of the bracket 2, which are used to assist the positioning of the mid-span deflection tester for the limit angle steel 4 The center of the threaded hole on the left side of the variable section platform 2-2 and the support 2 remains on the same horizontal line, that is, it is located on the central axis of the support. The right end, or the variable section at the two ends of the platform with twice the diameter of the screw is set at an angle of 45° with the central axis, the latter is selected in this embodiment.

In a specific embodiment of the present invention, the main parts are all made of aluminum alloy materials, and the screw rods can be generally used in the market.

To sum up, in the embodiments provided by the present invention, the invented adjustable deflection testing device can conveniently and flexibly fix deflection testing instruments of different types and specifications, so as to ensure accurate measurement of the net deflection of the mid-span, without Includes shear or torsional effects of the specimen on its support and is reusable.

This paper uses specific examples to illustrate the principle and implementation of the present invention, and the description of the above examples is only used to help understand the method and core idea of the present invention. It should be pointed out that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims (7)

1. The utility model provides a flexibility testing arrangement with adjustable be suitable for fibre concrete bending toughness test which characterized in that, includes two half rectangle vertical braces (1), two supports (2), a plurality of connecting screw (3), two spacing angle steel (4), a plurality of control screw (5), a plurality of punctual screw (6) and the test piece (7) that awaits measuring.

The semi-rectangular vertical support (1) is a frame structure with a downward opening and comprises a cross beam (1-4) and an upright post (1-5), and a rectangular cavity (1-3) is formed in the frame;

a cross beam (1-4) of the semi-rectangular vertical support (1) is provided with a first threaded hole (1-1) matched with the control screw rod (5).

The upright post (1-5) of the semi-rectangular vertical support (1) is provided with a second threaded hole (1-2) matched with the alignment point screw (6);

the whole bracket (2) is a rectangular plate, a variable cross-section platform (2-2) extends from one end of the plate, and a third threaded hole (2-1) is formed in the other end of the plate;

a sliding rail (2-3) is arranged in the middle of the bracket (2);

the top end of the connecting screw rod (3) is provided with a sliding part (3-1) matched with a sliding rail (2-3) of the bracket (2);

the limiting angle steel (4) is L-shaped angle steel consisting of two square plates, and a fourth threaded hole (4-1) matched with the connecting screw rod (3) is formed in one square plate;

the test piece (7) to be tested is a cuboid test piece; the two brackets (2) are attached to two transverse sides of a to-be-tested piece (7); the semi-rectangular vertical supports (1) span the two longitudinal ends of the to-be-tested piece (7) to clamp the support (2);

when the test device works, a to-be-tested piece (7) is fixed in the rectangular cavities (1-3) of the two semi-rectangular vertical supports (1); two semi-rectangular vertical supports (1) are fixed on a piece to be tested through an alignment point screw (6), a second threaded hole (1-2) of one semi-rectangular vertical support (1) is respectively connected with third threaded holes (2-1) of two supports (2) through the alignment point screw (6), and a second threaded hole (1-2) of the other semi-rectangular vertical support (1) is respectively connected with variable cross-section platforms (2-2) of the two supports (2) through the alignment point screw (6); one end of the connecting screw rod (3) provided with a sliding component (3-1) is arranged in a sliding rail (2-3) of the bracket (2); the connecting screw rod (3) fixes the limiting angle steel (4) on the bracket (2); and the limiting angle steel (4) fixes the deflection test displacement meter through the sliding rail (2-3).

2. The adjustable deflection testing device suitable for the fiber concrete bending toughness test according to claim 1, characterized in that the bracket (2) is further provided with an auxiliary limit angle steel (4) and a fixing through hole (2-4) for fixing a deflection testing displacement meter;

the through holes (2-4) for fixing are positioned at two sides of the sliding rails (2-3) and are symmetrically distributed along the central axis of the bracket (2).

3. The adjustable deflection testing device suitable for the fiber concrete bending toughness test according to claim 1, wherein the size of the variable cross-section platform (2-2) is larger than twice the diameter of the lap screw.

4. The adjustable deflection testing device suitable for the fiber concrete bending toughness test according to claim 1, wherein the variable cross-section platform (2-2) is a variable cross-section with an angle arranged at two ends of the platform with twice screw diameter.

5. The adjustable flexibility testing device suitable for the fiber concrete bending toughness test according to claim 1, wherein the groove of the slide rail (3) is a rectangular groove, a trapezoidal groove, a dovetail groove or a T-shaped groove.

6. The adjustable deflection testing device suitable for the fiber concrete bending toughness test is characterized in that the control screw (5) is used for adjusting the vertical height of the semi-rectangular vertical support (1), so that the alignment screw (6) is aligned with the intersection point of the action line of the cross section of the test piece and the central axis of the longitudinal section of the test piece to be tested on the two-point supporting device at the bottom of the bending test, and the support (2) is positioned at the central axis of the longitudinal section of the test piece to be tested.

7. The adjustable deflection testing device suitable for the fiber concrete bending toughness test according to claim 1, wherein the semi-rectangular vertical supports (1) and the bracket (2) are made of steel, aluminum alloy or iron.

Images