Device and method for testing adhesive property of anchoring interface of steel composite bar

Abstract

The invention discloses a steel composite bar anchoring interface bonding performance testing device which comprises a top connecting assembly and a bottom connecting assembly which are connected with the upper end and the lower end of a universal testing machine respectively. The steel frame structure forms a working space by a top plate, a bottom plate and a connecting rod; the test block fixing module is positioned in the space, is fixed on the steel frame bottom plate and is used for bonding the composite ribs; the displacement measuring assembly comprises a displacement meter and a measuring bracket, the bracket is fixed on the test block fixing module, and the displacement meter is mounted on the bracket; the composite bar anchoring module comprises an anchoring unit and a clamp, the anchoring unit fixes one end of the composite bar, the clamp is fixed on the steel frame bottom plate and is clamped with the anchoring unit, and the other end of the composite bar penetrates through the steel frame bottom plate and the test block fixing module and is abutted against the displacement meter. The device enables the displacement meter to directly measure the slippage, improves the connection stability of the anchoring unit, reduces the slippage of the anchoring end, avoids the deformation interference of a rib material, does not need to additionally test strain or displacement, accurately obtains the real slippage, simplifies the test, improves the accuracy, is reasonable in structure, and reduces the measurement error.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel bar performance testing, and particularly relates to a device and method for testing the bonding performance of a steel composite bar anchoring interface. BACKGROUND

[0002] In the field of civil engineering, steel bars in traditional building materials are widely used due to their good mechanical properties. However, with the continuous change of the use environment and engineering requirements, the corrosion resistance of steel bars has become increasingly prominent. In some harsh environments, such as marine environments and chemical corrosion environments, steel bars are prone to corrosion, which leads to deterioration of structural performance and seriously affects the safety and durability of structures, increasing the cost of engineering maintenance and safety hazards. At the same time, fiber reinforced polymer (FRP) bars, as a new type of material, have gradually entered the field of civil engineering. FRP bars have the advantages of strong corrosion resistance, light weight and high strength, and can effectively solve the corrosion problem of steel bars in harsh environments. However, FRP bars also have some obvious shortcomings, such as relatively low elastic modulus, large deformation under stress, and no obvious yield characteristics, which limits the application of FRP bars in structures with high deformation control requirements.

[0003] To overcome the shortcomings of FRP bars and steel bars and fully utilize the advantages of both, many researchers have combined FRP with steel to produce FRP-steel composite bars. This composite bar is composed of an inner core steel bar and an outer FRP protective layer. The outer FRP layer can effectively protect the inner core steel bar from corrosion and improve the durability of the steel bar. The inner core steel bar introduces the high elastic modulus of steel into the FRP material, which improves the low elastic modulus of the FRP bar and makes the composite bar have excellent mechanical properties and durability, making it have broad application prospects in the field of civil engineering.

[0004] Currently, when studying the bonding performance of steel-FRP composite bars and anchoring materials, traditional pull-out test devices are often used for testing. However, the traditional pull-out test device has some obvious shortcomings. The slip measured by the traditional device contains two parts, i.e., the slip between the bar and the anchoring material and the deformation of the bar itself. In order to obtain the true slip between the bar and the anchoring material, additional testing of the strain or displacement at the bottom of the bar is required, which increases the complexity and workload of the testing and also affects the accuracy of the test results. SUMMARY

[0005] The purpose of the present application is to disclose a device for testing the bonding performance of a steel composite bar anchoring interface, which can accurately measure the slip between the bar and the anchoring material.

[0006] In order to achieve the above object, the application discloses a kind of steel composite bar anchoring interface bonding performance testing device, comprising: top connection component, the top connection component is used to connect the upper end of universal testing machine;Bottom connection component, the bottom connection component is used to connect the lower end of universal testing machine;Steel frame structure, the steel frame structure includes the steel frame top plate connected with the top connection component, the steel frame bottom plate connected with the bottom connection component and the connecting rod between the steel frame top plate and the steel frame bottom plate, to form the working space between the steel frame top plate and steel frame bottom plate;Test block fixing module, the test block fixing module is located in the working space, and is fixed to the steel frame bottom plate, and the test block fixing module is used to be bonded with composite bar;Displacement measurement component, the displacement measurement component includes displacement meter and measurement support, and the measurement support is fixed to the test block fixing module, and the displacement meter is installed on the measurement support;Composite bar anchoring module, the composite bar anchoring module includes anchoring unit for clamping fixed composite bar and clamp, the anchoring unit is fixed to one end of the composite bar, and the clamp is fixed to the steel frame bottom plate, for fixed clamping with the anchoring unit, and the other end of the composite bar sequentially passes through the steel frame bottom plate and test block fixing module, and is in abutment with the displacement meter.

[0007] By adopting the above scheme, the displacement meter can directly measure the slip amount of the composite bar relative to the test block fixing module, and the anchoring unit is arranged between the clamp and the composite bar, which improves the connection stability between the clamp and the composite bar, can effectively reduce the slip of the anchoring end, provides a stable foundation for accurate measurement, avoids the interference of the deformation of the traditional device on the slip measurement, does not need to test the strain or displacement of the bottom of the bar, accurately obtains the real slip amount between the bar and the test block fixing module, simplifies the test process, and improves the accuracy of the test result. Meanwhile, the overall device structure is reasonable, the components are accurately positioned, the measurement error caused by the device structure and measurement method is reduced, and the bonding performance between the composite bar and the test block fixing module can be more accurately reflected.

[0008] Further, the test block fixing module has a through hole for the composite bar to pass through, and the through hole is composed of a non-bonding section and a bonding section, and the non-bonding section is located at one end of the through hole close to the steel frame bottom plate.

[0009] By adopting the above scheme, when measuring the slip amount, the displacement meter measures the displacement of the composite bar relative to the test block at the bonding section, which eliminates the interference of the deformation of the unbonded section composite bar itself and other non-bonding related factors on the measurement result, so that the real slip amount between the composite bar and the anchoring material can be obtained more accurately, and the problems of inaccurate measurement and complexity of the traditional device are solved. Avoiding stress concentration near the bottom plate to cause data distortion, preventing stress distortion, reducing error sources by 70%; ensuring that failure occurs at the target interface, controlling the failure mode, and reducing the risk of splitting by 60%.

[0010] Further, the unbonded section is provided with an isolation sleeve, and the inner diameter of the isolation sleeve is greater than the outer diameter of the composite bar.

[0011] By adopting the above scheme, if there is no isolation sleeve, the composite bar and the surrounding structure may have slight friction or bonding effect, which causes the measured slip amount to include unnecessary deformation of the composite bar itself and displacement caused by these additional effects, and the real bonding slip between the composite bar and the anchoring material cannot be accurately reflected. After setting the isolation sleeve with an inner diameter greater than the outer diameter of the composite bar, the composite bar can freely stretch and move in the unbonded section, and the isolation sleeve effectively isolates the direct contact between the composite bar and the surrounding structure, avoiding these interference factors, so that the displacement meter measures the relative displacement of the composite bar and the anchoring material in the bonding section, greatly improving the accuracy of the measurement result. The isolation sleeve forms a physical barrier to eliminate non-target bonding between concrete and composite bars, and the interference slip is reduced by 90%; the inner diameter gap ensures the free sliding of the reinforcing bar, and the friction resistance is less than 0.01 kN.

[0012] Further, the length of the isolation sleeve is consistent with the length of the composite bar passing out of the test block fixing module.

[0013] By adopting the above scheme, the displacement meter can accurately measure the slip amount of the composite bar in the bonding area, avoiding errors caused by unclear measurement range, and improving the accuracy of measurement. The length of the isolation sleeve is consistent with the length of the composite bar passing out, so that the stress state and boundary conditions of the composite bar in each test are basically the same. No matter how many tests are performed, the composite bar passing out part can be protected by the same isolation, avoiding the difference in test conditions caused by external factors, thereby ensuring the repeatability of the test, and making the data obtained by different batches of tests comparable.

[0014] Further, the measurement support includes: a support base assembled on the test block fixing module; a support beam assembled on the support base; a support column assembled on the support beam; and a clamping structure assembled on the support column, the clamping structure being used for clamping and fixing with the displacement meter.

[0015] By adopting the above scheme, the measuring support adopts the modular design of the support base, the support beam, the support column and the clamping structure, and the assembly relationship between each component is clear. During installation, the operator can operate in the order of first installing the support base on the test block fixing module, then sequentially installing the support beam and the support column, and finally fixing the displacement meter through the clamping structure. This modular installation method has clear steps, does not require complex tools and operation skills, greatly shortens the installation time, improves the installation efficiency, and is especially suitable for scenarios that require frequent disassembly and assembly for multiple tests. By reasonably designing the length and assembly position of the support beam and the support column, the position of the clamping structure can be accurately controlled, and then the measurement position of the displacement meter can be accurately controlled. This enables the displacement meter to accurately measure the slip amount between the composite bar and the anchoring material, avoiding errors caused by inaccurate measurement positions. For example, if the measurement position of the displacement meter deviates from the actual bonding interface between the composite bar and the anchoring material during the test, the measured slip amount will not truly reflect the bonding performance between the two. Accurate control of the displacement meter position can ensure the accuracy of the measurement data.

[0016] Further, the support base includes a first frame body and a second frame body, the first frame body and the second frame body are symmetrically connected to form a rectangular frame body, the support beam includes a first beam mounted on the first frame body and a second beam mounted on the second frame body, the first beam and the second beam are arranged in parallel and spaced apart, the support column includes a first column mounted on the first beam and a second column mounted on the second beam, and the clamping structure includes a first clamping member and a second clamping member for clamping the displacement meter, the first clamping member is assembled at the end of the first column, and the second clamping member is assembled at the end of the second column.

[0017] By adopting the above scheme, the beam can better bear the load transmitted by the column, and the load can be dispersed to a larger area through the base. The vertical connection mode of the column and the beam forms a stable frame structure, which can effectively resist the bending moment and torque that may occur during the test, ensuring the structural stability of the measuring support during the measurement process. The first frame body and the second frame body are connected in a symmetrical and buckled manner, and during installation, only the two need to be aligned and buckled, without the need for complex tools and operation steps. This installation method is not only convenient and fast, but also flexible according to the actual situation of the test block fixing module, ensuring that the base closely fits the test block fixing module and improving the accuracy and efficiency of the installation. The assembly method of the clamping structure makes the displacement meter and the measuring support form a whole, reducing the interference of external factors on the displacement meter and further improving the stability and accuracy of the measurement. At the same time, the clamping force of the clamping structure can be adjusted according to the size and weight of the displacement meter, ensuring that the displacement meter can be firmly fixed on the measuring support.

[0018] Further, the clamp has a clamping groove, an inner thread is arranged in the clamping groove, the anchoring unit is cylindrical, an outer thread is arranged on the outer side wall of the anchoring unit, the anchoring unit is threadedly connected with the clamping groove, the inner diameter of the anchoring unit is larger than the outer diameter of the composite bar, and a flexible adhesive material is filled between the anchoring unit and the composite bar.

[0019] By adopting the above scheme, the clamping groove of the clamp is provided with an inner thread, the outer side wall of the anchoring unit is provided with an outer thread, and the two are connected through threads. This connection method is simple to operate, and only needs to screw the anchoring unit into the clamping groove to complete the installation, without the need for complex tools and cumbersome steps, greatly shortening the installation time and improving the test preparation efficiency. At the same time, the threaded connection has good self-locking property, which can ensure that the anchoring unit will not loosen or fall off during the test process due to stress, ensuring the stability and safety of the test. The flexible adhesive material filled between the anchoring unit and the composite bar can more realistically simulate the bonding conditions between the composite bar and the surrounding matrix such as concrete in actual engineering. In actual engineering, the bonding between concrete and composite bars is not completely rigid, but has a certain flexibility and deformation ability. The flexible adhesive material can simulate this bonding property, making the test results closer to the actual situation and providing more reliable reference for engineering design and construction. The stability of threaded connection and the uniformity of flexible adhesive material help to reduce the error in the test process. Stable connection method can avoid measurement errors caused by loose or displaced parts, and uniform adhesive material filling can ensure uniform stress distribution on the bonding interface, reducing errors caused by stress concentration or unevenness.

[0020] Further, the connecting rod is threadedly connected with the steel frame top plate and the steel frame bottom plate to adjust the height of the working space, and the height of the working space ranges from 200mm to 500mm.

[0021] By adopting the above scheme, the connecting rod can realize relatively accurate height adjustment during rotation. The operator can accurately adjust the height of the working space by controlling the number of rotations according to actual needs, so as to meet the accurate height requirements of different tests. The working space height range is 200-500 mm, which can adapt to test blocks of various heights. In actual steel composite bar anchorage performance tests, the size of the test block may vary due to factors such as test purpose and material type. By adjusting the connecting rod to change the working space height, test blocks of different heights can be stably placed and tested in the device, expanding the application range of the device. The adjustable working space height design makes the test device more easily integrated with other related test equipment. For example, in some comprehensive material test systems, the steel composite bar anchorage performance test device may need to be combined with loading equipment, measurement equipment, control systems, etc. By adjusting the working space height, the spatial position relationship between the devices can be better coordinated, the devices can be seamlessly connected and work together, and the integration and efficiency of the entire test system can be improved.

[0022] Further, the flexible adhesive material is silicone sealant or epoxy resin.

[0023] By adopting the above scheme, the silicone sealant has excellent flexibility and elasticity and can deform within a large range without breaking. In the steel composite bar anchorage interface bonding performance test, when the composite bar is displaced by external force, the silicone sealant can freely stretch and contract with the deformation of the composite bar, without exerting excessive constraint force on the movement of the composite bar, thereby more realistically simulating the bonding state between the composite bar and the surrounding matrix in actual engineering. For example, in actual concrete structures, the concrete will shrink and creep, and the bonding interface between the composite bar and the concrete will also produce slight deformation. The flexibility of the silicone sealant can well adapt to such deformation. The epoxy resin has high bonding strength and can form a firm bonding layer with the surface of the steel composite bar and the anchoring unit. During the test, the high-strength bonding can ensure that the composite bar and the anchoring unit do not slide or separate relative to each other, thereby accurately measuring the anchorage performance of the composite bar. For example, in high-strength pull-out tests, the high bonding strength of the epoxy resin can ensure the accuracy and reliability of the test data.

[0024] The application discloses a method for testing the bonding performance of a steel composite bar anchoring interface, and adopts a steel composite bar anchoring interface bonding performance testing device, and comprises the following steps: preparing an anchoring material test block; the top of the composite bar is extended by 20 mm from the surface of the prepared anchoring material test block, and the bottom is inserted into an anchoring unit and sealed with epoxy resin; assembling a measuring support; the measuring support is connected to the bottom plate of the steel frame through a plurality of bolts, and a certain working space is reserved; installing a displacement measuring assembly; the measuring support is fixed on the anchoring material test block, the clamping distance of the clamping structure in the measuring support is adjusted, and the displacement meter probe is vertically contacted with the top of the composite bar; connecting the anchoring module; the anchoring unit is threadedly connected with the clamp, and the clamp base is fixed on the steel frame bottom plate through bolts; connecting the universal testing machine; the top connecting assembly is connected to the upper end of the testing machine through a top bolt, and the bottom connecting assembly is connected to the lower end of the testing machine through a bottom bolt; the universal testing machine is loaded at a rate of ≤20 kN / min or 1 mm / min, the displacement of the displacement meter and the load value of the universal testing machine are synchronously collected, and the displacement of the composite bar relative to the anchoring material test block is the displacement of the displacement meter.

[0025] By adopting the above scheme, the anchoring state of the steel composite bar in the anchoring material such as concrete in the actual engineering is simulated by preparing the anchoring material test block and inserting the composite bar into the anchoring material test block in a specific manner. Meanwhile, the bottom is sealed with epoxy resin, the bonding between the anchoring unit and the composite bar is ensured, and the interference of external factors is prevented to a certain extent, so that the test environment is closer to the actual working condition, and more valuable test results are obtained. According to different diameters and lengths of the steel composite bar, the size of the anchoring material test block, the specification of the anchoring unit and the clamping distance of the measuring support can be adjusted, and the bonding performance of the anchoring interface of the composite bar of different specifications can be tested. The universality of the method enables the method to be widely applied to quality detection and performance research of various types of steel composite bar products.

[0026] Compared with the prior art, the application has the following beneficial effects: 1. The slippage measured by the traditional pull-out test device contains the slippage between the bar and the anchoring material and the deformation of the bar itself, while the displacement meter directly measures the slippage between the composite bar and the test block fixing module in the device. Meanwhile, the anchoring unit is arranged between the clamp and the composite bar, the connection stability between the clamp and the composite bar is improved, the slippage at the anchoring end is effectively reduced, the interference of the deformation of the bar itself on the slippage measurement in the traditional device is avoided, and the real slippage between the bar and the test block fixing module can be accurately obtained without additional testing of the strain or displacement of the bottom of the bar. 2. The measuring support is fixed on the test block fixing module, and the displacement meter is installed on the measuring support. This stable installation mode ensures the accuracy of the displacement meter measurement. Moreover, the steel frame structure provides stable support for each component, reduces measurement errors caused by device structure and measurement method, and can more accurately reflect the bonding performance between the composite bar and the test block fixing module, making the overall device structure reasonable and the positioning of each component accurate; 3. The top connecting assembly and the bottom connecting assembly are respectively used to connect the upper end and the lower end of the universal testing machine, and the connection method is simple and direct. The connecting rod of the steel frame structure is connected between the steel frame top plate and the bottom plate by screw connection. This connection method is not only firm, but also facilitates the adjustment of the height of the working space to adapt to test blocks and test requirements of different sizes. The installation and disassembly of components such as the test block fixing module, the displacement measurement assembly and the composite bar anchoring module are relatively simple, which can save test preparation time and improve work efficiency. Since the device can directly measure the required real slip, it is not necessary to test the strain or displacement at the bottom of the reinforcement as in the traditional device, which simplifies the test process. The operator only needs to follow the specified steps to assemble the device, install the test block, adjust the displacement meter and perform the loading test, etc. to complete the test, reducing the complexity and workload of the operation and reducing the influence of human factors on the test results; 4. By accurately measuring the real slip between the composite bar and the test block fixing module, and combining with the load value measured by the universal testing machine, the accurate bond-slip relationship curve can be obtained. This real bond performance data can provide reliable basis for the design, construction and use of steel composite bars in the field of civil engineering, and help to optimize the anchoring method of composite bars and improve the safety of the structure; Due to the stable structure of the device and the accurate measurement, consistent test results can be obtained under different test conditions and multiple repeated tests. Good repeatability enables researchers to conduct in-depth research and analysis on the bonding performance of the steel composite bar anchoring interface, compare different factors; 5. The device has strong versatility and can adapt to different types and specifications of steel composite bars. Whether it is a composite bar of different diameters and lengths, or a composite bar composed of different materials, it only needs to adjust the size of the test block fixing module, the specification of the anchoring unit and the clamping distance of the measuring support according to the actual situation. The bonding performance test of the anchoring interface can be carried out, which provides an effective test means for various types of steel composite bar products; In the field of civil engineering, different engineering structures have different requirements for the anchoring performance of steel composite bars. The device can simulate different engineering environments and use conditions to test the bonding performance of steel composite bars under different anchoring materials and different loading methods, provide targeted data support for engineering design and construction, and meet the actual needs of different engineering. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0028] Figure 1 A longitudinal sectional structure schematic diagram of the embodiment of the present application.

[0029] Figure 2 A top connecting assembly bottom structure schematic diagram of the embodiment of the present application.

[0030] Figure 3 A steel frame top plate hole structure schematic diagram of the embodiment of the present application.

[0031] Figure 4 A steel frame bottom plate hole structure schematic diagram of the embodiment of the present application.

[0032] Figure 5 A measurement support three-dimensional structure schematic diagram of the embodiment of the present application.

[0033] Figure 6 A clamp sectional structure schematic diagram of the embodiment of the present application.

[0034] Main drawing mark explanation: 1, top connecting assembly; 11, top bolt; 2, bottom connecting assembly; 21, bottom bolt; 3, steel frame structure; 31, steel frame top plate; 32, steel frame bottom plate; 33, connecting rod; 4, test block fixing module; 41, through hole; 411, unbonding section; 412, bonding section; 413, isolation sleeve; 42, spiral hoop; 5, displacement measurement assembly; 51, displacement meter; 52, measurement support; 521, support base; 5211, first frame body; 5212, second frame body; 522, support beam; 5221, first beam; 5222, second beam; 523, support column; 5231, first column; 5232, second column; 524, clamping structure; 5241, first clamping piece; 5242, second clamping piece; 6, composite bar anchoring module; 61, anchoring unit; 62, clamp; 621, clamping groove; 63, flexible adhesive material; 7, composite bar; 8, working space. DETAILED DESCRIPTION

[0035] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0036] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0037] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. Those of ordinary skill in the art can understand the specific meaning of these terms in the present application according to the specific circumstances.

[0038] In addition, the terms "mount", "set", "provided with", "connected", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two devices, elements or components. Those of ordinary skill in the art can understand the specific meaning of the above-mentioned terms in the present application according to the specific circumstances.

[0039] In addition, the terms "first", "second", and the like are mainly used to distinguish different devices, elements or components (the specific types and structures can be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "multiple" is two or more.

[0040] The technical solutions of the present application will be further described below in conjunction with the embodiments and drawings.

[0041] Embodiment 1 of the present application is described below Figures 1 to 6As shown, a steel composite bar anchorage interface bonding performance test device is provided, comprising a top connecting assembly 1, a bottom connecting assembly 2, a steel frame structure 3, a test block fixing module 4, a displacement measuring assembly 5 and a composite bar anchorage module 6, the top connecting assembly 1 is used to connect the upper end of the universal testing machine, specifically, the top connecting assembly 1 is connected with the upper end of the universal testing machine through a top bolt 11, the top bolt 11 is threadedly connected with a top connecting piece, this connection method is simple and reliable, and is convenient to install and disassemble. The bottom connecting assembly 2 is used to connect the lower end of the universal testing machine, specifically, the bottom connecting assembly 2 is connected with the lower end of the universal testing machine through a bottom bolt 21, the bottom bolt 21 is threadedly connected with a bottom connecting piece, this connection method is simple and reliable, and is convenient to install and disassemble.

[0042] In this embodiment 1, the steel frame structure 3 comprises a steel frame top plate 31 connected with the top connecting assembly 1, a steel frame bottom plate 32 connected with the bottom connecting assembly 2 and a connecting rod 33 located between the steel frame top plate 31 and the steel frame bottom plate 32, so as to form a working space 8 between the steel frame top plate 31 and the steel frame bottom plate 32; optionally, the connecting rod 33 is four high-strength bolts, and the bolt length is adjustable between 200mm-500mm. This adjustable length design enables the device to adapt to test blocks and test requirements of different sizes, improving the versatility of the device. At the same time, the use of high-strength bolts ensures the strength and stability of the steel frame structure 3, which can withstand the tension applied by the universal testing machine during the test without obvious deformation or shaking, providing a stable working space 8 for the test and reducing the influence of frame deformation on the measurement results. Ensures the stable connection of the top connecting assembly 1 and the steel frame top plate 31, providing a stable foundation for the connection of the entire device with the upper end of the universal testing machine, ensuring that there will be no measurement errors due to loose connection during the test. Specifically, the steel frame bottom plate 32 is provided with a through hole 41 with a diameter of about 22mm in the center, which can adapt to composite bars 7 with a diameter of 8mm-20mm. The design of the through hole 41 provides convenience for the passage of the composite bar 7, and its size range can meet the test requirements of composite bars 7 of various specifications, further embodying the versatility of the device.

[0043] In some embodiments, the length of the isolation sleeve 413 is consistent with the length of the composite bar 7 protruding out of the test block fixing module 4. If the length of the isolation sleeve 413 is shorter than the length of the composite bar 7 protruding out of the test block fixing module 4, the protruding part of the composite bar 7 will directly contact the surrounding environment or other structures. During the test process, when the composite bar 7 is subjected to tension and slides, this direct contact will generate additional friction, affecting the free sliding of the composite bar 7, leading to inaccurate measurement of the slip amount by the displacement meter 51, including false displacement caused by additional friction. When the length of the isolation sleeve 413 is consistent with the protruding length, the part of the composite bar 7 protruding out of the test block fixing module 4 is completely wrapped by the isolation sleeve 413, effectively avoiding direct contact with the outside world, eliminating additional friction interference, and making the measured slip amount truly reflect the bonding and sliding conditions between the composite bar 7 and the anchoring material. The matching of the length of the isolation sleeve 413 with the protruding length of the composite bar 7 clearly defines the effective range of measurement. In the test, we are interested in the relative slip of the composite bar 7 in the specific bonding area, i.e., within the test block fixing module 4, and the anchoring material. The isolation sleeve 413 effectively isolates the non-measurement area, i.e., the part of the composite bar 7 protruding out, from the measurement area, so that the displacement meter 51 can accurately measure the slip amount of the composite bar 7 in the bonding area, avoiding errors caused by unclear measurement range and improving the accuracy of measurement. When the length of the isolation sleeve 413 is insufficient, the friction generated by the contact between the protruding part of the composite bar 7 and the outside world will be transmitted to the bonding area through the composite bar 7, leading to uneven stress distribution in the bonding area. This uneven stress distribution may cause abnormal changes in the bonding performance between the composite bar 7 and the anchoring material, affecting the stability of the test results. When the length of the isolation sleeve 413 is consistent with the protruding length, the transmission path of external friction to the bonding area is cut off, ensuring the uniformity of stress distribution in the bonding area, allowing the test to be conducted in a relatively stable stress state, and improving the reliability of the test results. During the test process, if the protruding part of the composite bar 7 rubs or collides with the outside world, it may cause surface damage or local deformation of the composite bar 7. This local damage not only affects the mechanical properties of the composite bar 7 itself, but also may change the bonding interface characteristics between the composite bar 7 and the anchoring material, thereby affecting the stability of the entire test. The isolation sleeve 413 completely protects the protruding part of the composite bar 7, avoiding damage to the composite bar 7 by external factors, and ensuring the integrity and stability of the structure during the test process.

[0044] The test block fixing module 4 is located in the working space 8 and is fixed to the steel frame bottom plate 32, and is used for bonding with the composite bar 7. Specifically, the test block fixing module 4 is internally provided with a through hole 41, which is divided into an upper bonding section and a lower non-bonding section 411. The upper bonding section enables the composite bar 7 to be in direct contact with the concrete, thereby simulating the bonding state of the composite bar 7 and the anchoring material in an actual project. The lower non-bonding section 411 is provided with an isolation sleeve 413, which is preferably made of PVC material. The isolation sleeve 413 effectively isolates the bonding between the composite bar 7 and the concrete, avoids the interference of the non-bonding area on the test results, and thus can more accurately measure the bonding performance between the composite bar 7 and the concrete.

[0045] In some embodiments, the inner diameter of the isolation sleeve 413 is larger than the outer diameter of the composite tendon 7. In a conventional test method, if there is no isolation sleeve 413, the composite tendon 7 and the surrounding structure can have a slight friction or bonding effect, resulting in the measured slip amount containing unnecessary deformation of the composite tendon 7 itself and displacement caused by these additional effects, which cannot accurately reflect the true bond slip between the composite tendon 7 and the anchoring material. After setting the isolation sleeve 413 with an inner diameter larger than the outer diameter of the composite tendon 7, the composite tendon 7 can freely stretch and move in the unbonded section 411, and the isolation sleeve 413 effectively isolates the direct contact between the composite tendon 7 and the surrounding structure, avoiding these interference factors, so that the displacement measured by the displacement meter 51 is purely the relative displacement of the composite tendon 7 and the anchoring material in the bonded section 412, greatly improving the accuracy of the measurement results. During the test process, any slight additional force or friction can cause cumulative measurement errors. The isolation sleeve 413 provides a relatively independent and unconstrained space for the composite tendon 7, preventing error transmission and accumulation due to the interaction between the composite tendon 7 and the surrounding structure. For example, in repeated loading tests, without the isolation sleeve 413, the friction between the composite tendon 7 and the surrounding structure may change with the number of loadings, resulting in increasing measurement errors; with the isolation sleeve 413, this error accumulation phenomenon is effectively controlled, ensuring the accuracy and consistency of each measurement. When the composite tendon 7 is subjected to tensile force, stress concentration is likely to occur at the junction between the unbonded section 411 and the bonded section 412. If there is no isolation sleeve 413, stress can be transmitted through the contact between the composite tendon 7 and the surrounding structure, further exacerbating stress concentration, and even causing damage to the composite tendon 7 or the surrounding structure, affecting the stability of the device. The isolation sleeve 413 with an inner diameter larger than the outer diameter of the composite tendon 7 provides a certain deformation space for the composite tendon 7, which can disperse and alleviate stress concentration, making the stress on the composite tendon 7 more evenly distributed, thereby enhancing the overall stability of the device and ensuring the safety and stability of the test. During the test process, the composite tendon 7 may deviate slightly due to uneven stress or minor vibrations of the device. If there is no isolation sleeve 413, the composite tendon 7 may be stuck with the surrounding structure, causing the test to fail or the measurement results to be inaccurate. The isolation sleeve 413 with an inner diameter larger than the outer diameter of the composite tendon 7 provides a certain amount of movement for the composite tendon 7, so that even if the composite tendon 7 deviates slightly, it can still move freely within the isolation sleeve 413 without being stuck, ensuring the stability of the device and the smooth progress of the test.

[0046] In some embodiments, the test block fixing module 4 is optionally provided with a spiral hoop 42, which can increase the splitting strength by 120%. During the test, as the pulling force increases, the test block fixing module 4 may be subjected to splitting failure. The spiral hoop 42 enhances the integrity of the test block, prevents premature splitting of the test block, and ensures that the test can be performed before the test block and the composite bar 7 are damaged at the bonding interface, thereby obtaining accurate bonding performance data.

[0047] The displacement measuring assembly 5 comprises a displacement meter 51 and a measuring support 52 fixed to the test block fixing module 4, and the displacement meter 51 is installed on the measuring support 52. Specifically, the measuring support 52 is an aluminum support, and in some embodiments, the measuring support 52 comprises a support base 521, a support beam 522, a support column 523 and a clamping structure 524. The support base 521 is assembled on the test block fixing module 4, the support beam 522 is assembled on the support base 521, the support column 523 is assembled on the support beam 522, and the clamping structure 524 is assembled on the support column 523. The clamping structure 524 is used for clamping and fixing the displacement meter 51. In this embodiment 1, the support base 521 comprises a first frame body 5211 and a second frame body 5212, which are symmetrically connected to form a rectangular frame body. The rectangular structure itself has good stability and can uniformly disperse the pressure from the support beam 522, the column and the displacement meter 51 above. The symmetrical connection further enhances the integrity and strength of the base, so that it is not easy to deform or be damaged when bearing various external forces during the test, and provides reliable foundation support for the entire measuring support 52. The support beam 522 comprises a first beam 5221 installed on the first frame body 5211 and a second beam 5222 installed on the second frame body 5212. The first beam 5221 and the second beam 5222 are arranged in parallel and spaced apart. This design enables the beam to better bear the load transmitted by the column and disperse the load to a larger area through the base. At the same time, the first column 5231 is installed on the first beam 5221, and the second column 5232 is installed on the second beam 5222. The vertical connection of the column and the beam forms a stable frame structure, which can effectively resist the bending moment and torque that may be generated during the test, and ensures the structural stability of the measuring support 52 during the measurement. The support column 523 comprises a first column 5231 installed on the first beam 5221 and a second column 5232 installed on the second beam 5222. The clamping structure 524 comprises a first clamping piece 5241 and a second clamping piece 5242 for clamping the displacement meter 51. The first clamping piece 5241 is assembled at the end of the first column 5231, and the second clamping piece 5242 is assembled at the end of the second column 5232. The design of the first clamping piece 5241 and the second clamping piece 5242 can stably clamp the displacement meter 51 and prevent the displacement meter 51 from shaking or shifting during the measurement. The assembly of the clamping structure 524 makes the displacement meter 51 and the measuring support 52 form an integral whole, reduces the interference of external factors on the displacement meter 51, and further improves the stability and accuracy of the measurement.Meanwhile, the clamping force of the clamping structure 524 can be adjusted according to the size and weight of the displacement meter 51, so as to ensure that the displacement meter 51 is firmly fixed on the measuring support 52.

[0048] It should be noted that the first frame 5211 and the second frame 5212 are C-shaped supports, and are fixed on the upper surface of the test block fixing module 4. This fixing mode is simple and firm, and the aluminum support has the characteristics of light weight and high strength, and will not have additional influence on the test results.

[0049] The displacement meter 51 is clamped between the first clamping piece 5241 and the second clamping piece 5242. Specifically, the first clamping piece 5241 has a front clamping groove, and the second clamping piece 5242 has a rear clamping groove. The displacement meter 51 is clamped between the front clamping groove and the rear clamping groove, and the measuring head vertically contacts the top free end of the composite bar 7. The rear clamping groove is adjusted by two groups of bolt holes to ±15mm, which can adapt to the size tolerance of the test block. The front clamping groove is adjusted by a precision bolt to ±0.1mm, which can ensure that the pre-pressing amount of the displacement meter 51 is 5%. Experimental data shows that the perpendicularity deviation of the displacement meter 51 axis and the composite bar 7 is less than or equal to 0.05° after adjustment. This high-precision adjusting mechanism ensures that the displacement meter 51 can accurately measure the slip amount of the composite bar 7 relative to the test block, and improves the accuracy of the measurement results.

[0050] The composite bar anchoring module 6 comprises an anchoring unit 61 for clamping the composite bar 7 and a clamp 62, the anchoring unit 61 is fixed to one end of the composite bar 7, the clamp 62 is fixed to the steel frame bottom plate 32 for fixed clamping with the anchoring unit 61, the other end of the composite bar 7 passes through the steel frame bottom plate 32 and the test block fixing module 4 in turn, and abuts against the displacement meter 51. Optionally, the anchoring unit 61 is in a cylindrical shape, specifically a steel pipe structure, the bottom of the composite bar 7 is inserted into the steel pipe structure of the anchoring unit 61, the inner surface of the steel pipe is provided with threads, and the steel pipe is filled with epoxy resin, the micro-threads on the inner wall of the steel pipe increase the bonding area by 40%, the strength of the epoxy resin is ≥30MPa, and the anchoring force reaches 115% of the ultimate tensile force of the reinforcing material. This anchoring method can ensure firm connection between the bottom of the composite bar 7 and the steel pipe, effectively reduce the slip at the anchoring end, and provide a stable basis for accurate measurement. The steel pipe structure is connected with the clamp 62 through external threads, the clamp 62 has a clamping groove 621 in a tubular shape, the clamping groove 621 is provided with internal threads, the outer side wall of the anchoring unit 61 is provided with external threads, the anchoring unit 61 is connected with the clamping groove 621 through threads, the inner diameter of the anchoring unit 61 is larger than the outer diameter of the composite bar 7, and the anchoring unit 61 and the composite bar 7 are filled with a flexible adhesive material 63, and the flexible adhesive material 63 is epoxy resin. The inner diameter of the anchoring unit 61 is larger than the outer diameter of the composite bar 7, during installation, the composite bar 7 can be placed in a suitable position first, and then the flexible adhesive material 63 is uniformly filled in the gap between the anchoring unit 61 and the composite bar 7. This filling method is flexible and convenient, the filling amount and uniformity of the adhesive material can be controlled according to actual needs, the filling process is not disturbed by other components, and the installation can be quickly completed by the operator. The flexible adhesive material 63 filled between the anchoring unit 61 and the composite bar 7 can more truly simulate the bonding condition between the composite bar 7 and the surrounding concrete matrix in actual engineering. In actual engineering, the bonding between the concrete and the composite bar 7 is not completely rigid, but has a certain flexibility and deformation ability. The flexible adhesive material 63 can simulate this bonding property, so that the test result is closer to the actual situation, and a more reliable reference basis is provided for engineering design and construction. The internal threads of the clamp 62 adopt M20 standard metric threads, and the diameter conversion can be completed within 5 minutes. This design enables the device to adapt to composite bars 7 of different diameters, improves the versatility and operation convenience of the device. The clamping groove 621 of the clamp 62 is provided with internal threads, the outer side wall of the anchoring unit 61 is provided with external threads, and the two are connected through threads. This connection method is simple to operate, the installation can be completed by simply rotating the anchoring unit 61 into the clamping groove 621, without the need for complex tools and cumbersome steps, which greatly shortens the installation time and improves the test preparation efficiency. At the same time, the threaded connection has good self-locking property, which can ensure that the anchoring unit 61 will not loosen or fall off during the test process due to stress, thereby ensuring the stability and safety of the test.

[0051] It should be noted that the micro thread on the inner wall of the steel pipe increases the bonding area, the epoxy resin provides high strength anchoring force, and the inner thread of the clamp 62 is a standard metric thread, which is convenient for diameter conversion. See the following table: Component Parameter Effect Steel pipe inner wall Micro thread (0.3mm deep) Increase 40% bonding area Epoxy resin Strength ≥ 30MPa Anchoring force up to 115% of the ultimate tensile strength of the reinforcement Inner thread of the clamp clamping groove M20 standard metric thread Complete diameter conversion within 5 minutes The design of these parameters enables the composite bar anchoring module 6 to firmly fix the composite bar 7, effectively reduces the slip at the anchoring end, and provides a stable basis for accurate measurement.

[0052] The comparative test was conducted using a composite bar 7 with a diameter of 16 mm, and the results showed that the device is superior to the traditional device in terms of standard deviation of slip, extreme difference of bonding strength, and FRP layer damage rate, etc. Specifically as follows: Indicator Traditional device The device Slip amount standard deviation ±0.18mm ±0.04mm Bonding strength range 8.7% 2.1% FRP layer damage rate 22% 0% The standard deviation of slip is reduced from ±0.18 mm of the traditional device to ±0.04 mm, indicating that the slip data measured by the device is more concentrated, has small dispersion, and the measurement result is more accurate; the extreme difference of bonding strength is reduced from 8.7% to 2.1%, indicating that the device can more stably measure the bonding strength between the composite bar 7 and the anchoring material; the FRP layer damage rate is reduced from 22% to 0%, indicating that the testing process of the device causes less damage to the composite bar 7, further ensuring the reliability of the test results.

[0053] With the development of civil engineering technology, the requirements for structural performance are becoming higher and higher. Not only does the structure need to have enough safety, but it also needs to have good durability. Research has found that high-performance composite material structures can meet these requirements. By optimizing the combination of materials with different properties, the advantages of each material can be fully utilized to improve the overall performance of the structure. Therefore, high-performance composite material structures have been widely developed and applied. FRP-steel composite bars, as a new type of material, combined with high-performance materials such as engineered cementitious composites (ECC) and ultra-high performance concrete (UHPC), can further improve the performance of the structure. However, to realize the effective application of these high-performance material composite structures, it is essential to study the bonding performance of composite bars and high-performance materials. Because the bonding performance directly affects the stress transfer and cooperative working ability between materials in the composite structure, only with good bonding performance can the composite bar and high-performance materials work together to bear external forces, fully utilize the high-strength characteristics of the composite bar, and ensure the safety and reliability of the composite structure. The bonding performance between steel-FRP composite bars and anchoring materials plays a crucial role in stress transfer in structures. In civil engineering structures, external forces need to be transmitted to steel-FRP composite bars through anchoring materials. Good bonding performance can ensure that steel-FRP composite bars and anchoring materials work together to effectively transfer external forces to the composite bar, allowing it to fully utilize its high-strength characteristics and ensure the normal stress performance of the structure. On the contrary, if the bonding performance is poor, it will lead to uneven stress between steel-FRP composite bars and anchoring materials, and under the action of external forces, local peeling may occur. Once local peeling occurs, not only will it reduce the carrying capacity of the structure, but it may also cause damage to the structure, endangering the safety of the entire structure and causing serious consequences for the project. Therefore, it is necessary to conduct testing and research on the bonding performance of steel-FRP composite bars and anchoring materials to understand the bonding mechanism between the two and provide scientific basis for the design and construction process optimization of structures.

[0054] Inverted loading and real slip capture: The slip measured by traditional devices contains the deformation caused by the strain at the bottom of the bar and the interface slip. The slip needs to be calculated by measuring the strain at the bottom of the bar, which is a complex process and prone to errors. The device directly measures the real slip between the composite bar and the anchoring material due to the absolute anchoring at the bottom (L=0), avoiding the interference of the deformation of the bar itself on the slip measurement in traditional devices. It does not need to test the strain or displacement at the bottom of the bar, simplifying the testing process and improving the accuracy of the measurement results.

[0055] In operation, the universal testing machine pulls up the steel frame top plate 31, the test block fixing module 4 moves up with the frame, the interface bonding force drags the composite bar 7, and only the top free end generates displacement. This inverted loading mode enables the displacement meter 51 to clearly measure the slip amount of the composite bar 7 relative to the test block, conforms to the stress state of the composite bar 7 in actual engineering, and can more truly reflect the bonding performance between the composite bar 7 and the anchoring material.

[0056] In some embodiments, the end of the PVC isolation sleeve 413 is coated with a 1mm thick silicone sealant, which forms an IP68 level sealing barrier after curing, and no leakage is found after 300 hours of salt spray test. This sealing process effectively prevents the concrete slurry from entering the unbonded section 411, ensuring the isolation effect of the unbonded section 411.

[0057] The effect comparison is shown in the following table: Test group Interference slip amount No isolation sleeve 0.15mm Isolation design of the device 0.01mm Without the isolation sleeve 413, the interference slip is 0.15mm; after using the isolation design of the device, the interference slip is reduced to 0.01mm. This shows that the isolation technology of the unbonded section 411 of the device can effectively reduce the interference of the non-bonding area on the test results, and improve the accuracy of the measurement results.

[0058] In some embodiments, the rear clamping slot of the aluminum vehicle support is used for coarse adjustment, and the front clamping slot is used for fine adjustment. Specifically, the rear clamping slot is adjusted by ±15mm through two groups of bolt holes for coarse adjustment, and the size tolerance of the test block fixing module 4 is adapted. The front clamping slot is adjusted by ±0.1mm through precise bolts for fine adjustment, and the pre-pressing amount of the displacement meter 51 is guaranteed to be 5%. Through the combination of coarse adjustment and fine adjustment, the position of the displacement meter 51 can be accurately adjusted, and the measuring head of the displacement meter 51 is ensured to vertically contact the top free end of the composite bar 7. After adjustment, the perpendicularity deviation between the axis of the displacement meter 51 and the composite bar 7 is ≤0.05°. This high-precision adjustment mechanism ensures the accuracy of the measurement of the displacement meter 51 and reduces the measurement error caused by inaccurate installation of the displacement meter 51.

[0059] The present application also relates to a method for testing the anchoring interface bonding performance of a steel composite bar, which uses a device for testing the anchoring interface bonding performance of a steel composite bar, and comprises the following steps: Preparation of the anchoring material test block: the top of the composite bar 7 extends 20mm above the surface of the prepared anchoring material test block, and the bottom is inserted into the anchoring unit 61 and sealed with epoxy resin; Assembly of the measurement support 52: the measurement support 52 is connected to the steel frame bottom plate 32 through multiple groups of bolts, and a certain working space 8 is reserved; Installation of the displacement measurement assembly 5: the measurement support 52 is fixed on the anchoring material test block, and the clamping distance of the clamping structure 524 in the measurement support 52 is adjusted so that the measuring head of the displacement meter 51 vertically contacts the top of the composite bar 7; Connecting anchor module: thread the anchor unit 61 with the clamp 62, and the clamp 62 base is fixed on the steel frame bottom plate 32 by bolts; Universal testing machine: the top connecting assembly 1 is connected to the upper end of the testing machine through the top latch 11, and the bottom connecting assembly 2 is connected to the lower end of the testing machine through the bottom latch 21; The universal testing machine is loaded at a rate of ≤20kN / min or 1mm / min, and the displacement of the displacement meter 51 and the load value of the universal testing machine are collected synchronously. The displacement of the displacement meter 51 is the displacement of the composite bar 7 relative to the anchoring material test block.

[0060] By preparing the anchoring material test block and inserting the composite bar 7 into it in a specific way, the anchoring state of the steel composite bar 7 in the anchoring material such as concrete in actual engineering is more realistically simulated. At the same time, the bottom is sealed with epoxy resin, which not only ensures the bonding between the anchoring unit 61 and the composite bar 7, but also prevents external factors from interfering to some extent, making the test environment closer to the actual working condition, so as to obtain more valuable test results. The method can realize the bonding performance test of the anchoring interface of composite bars 7 of different specifications by adjusting the size of the anchoring material test block, the specification of the anchoring unit 61, and the clamping distance of the measuring support 52, etc. The universality of the method makes it widely applicable to quality detection and performance research of various types of steel composite bars 7 products.

[0061] It should be noted that in the above embodiments, the steps have no fixed order and can achieve the above effects.

[0062] In some embodiments, the steps have a certain fixed order, and the specific steps are as follows: Step 1: Prepare the anchoring material test block: The composite bar 7 protrudes 20±0.5mm from the surface of the concrete test block, and the precise control of the protruding length can ensure the consistency and comparability of the test. The PVC isolation sleeve 413 is sleeved on the unbonded section 411, and the end is sealed with silicone sealant, with a curing time of 24h, to ensure the isolation effect of the unbonded section 411 and prevent the concrete slurry from entering the unbonded section 411 to affect the test results.

[0063] Step 2: Assembly of the device: Adjust the height of the working space 8 to 120mm by adjusting the high-strength bolts, which can adapt to 100mm test blocks. Adjust the height of the working space 8 according to the size of the test block to ensure that the test block can be installed and tested smoothly. The aluminum measuring support 52 takes about 5 minutes to install, while the traditional welded support takes 30 minutes. The aluminum measuring support 52 of the device is easy and fast to install, greatly shortening the test preparation time and improving the work efficiency.

[0064] Step 3: Data collection: Loading rate: 1mm / min (key parameter in the adhesive softening stage), the appropriate loading rate can accurately capture the bond performance change between the composite bar 7 and the anchoring material, especially in the adhesive softening stage, and more accurate test data can be obtained.

[0065] Sampling frequency: displacement meter 5150Hz, load sensor 10Hz; higher sampling frequency can record the displacement and load changes in real time during the test, providing more detailed information for subsequent data analysis.

[0066] Experimental results: The composite bar 7 with a diameter of 16mm in the anchoring material test block is tested, and the test is as follows: Load (kN) Traditional device slip amount (mm) Device slip amount (mm) 30 0.12±0.03 0.05±0.01 80 0.48±0.10 0.22±0.02 120 1.25±0.18 0.83±0.03 The results show that the dispersion of the slip amount data measured by the device is reduced by 85%. This indicates that the test method of the device can more stably measure the slip amount between the composite bar 7 and the anchoring material, improving the accuracy and reliability of the test results.

[0067] Embodiment 2 of the present application, based on embodiment 1, can install a second displacement meter 51 at the bottom end of the composite bar 7 according to the way and structure of installing the displacement meter 51 at the top end of the composite bar 7, and the universal testing machine pulls up the steel frame to realize synchronous acquisition of bidirectional displacement, and the slip amount is directly calculated by the displacement difference of the two ends, eliminating the interference of frame deformation in the traditional method.

[0068] The experimental results are as follows: Indicator The scheme The original scheme Data redundancy Double-channel verification Single channel System error ±0.8% ±0.5% Cross-validated data reliability, suitable for scientific calibration, double-channel verification, independent acquisition of top and bottom displacement, data reliability improved by 50%, and abnormal values can be identified through cross-validation. Stronger anti-interference ability, suitable for scenes with environmental vibration or larger frame flexibility. It meets the scientific calibration, double-channel data can be cross-verified, suitable for sensor calibration or algorithm development. Real-time monitoring, synchronous display of double-end displacement, convenient for dynamic adjustment during the experiment.

[0069] Embodiment 3 of the present application, based on embodiment 1, increases the fiber Bragg grating sensing method, pre-buries the FBG fiber Bragg grating sensor on the surface of the bonding section of the composite bar 7, realizes distributed strain monitoring, the universal testing machine pulls up the steel frame, collects the wavelength shift Δλ of the optical fiber and converts the strain distribution, obtains the strain field of the bonding section through the high-density fiber Bragg grating array, and realizes the integral calculation of the slip amount.

[0070] The experimental results are as follows: Indicator The scheme The original scheme Spatial resolution 1mm Overall displacement Cost ￥12,000 / time ￥850 / time The bonding stress distribution cloud map is obtained, which is suitable for mechanism research, the spatial resolution is 1 mm, which is much better than the original whole displacement measurement scheme, local bonding failure can be captured, the cost is significantly increased compared with the original scheme, but high value-added data is provided. The advantages are that the bonding stress distribution cloud map can be generated to reveal the interface damage evolution law; the fiber grating is corrosion-resistant and anti-electromagnetic interference, suitable for long-term service performance evaluation; it can be extended to synchronous monitoring of temperature and strain to analyze the thermal-mechanical coupling effect.

[0071] The technical effect experiment verification is carried out based on example 1 as follows: 1. Anchorage reliability test: After 2000 times of fatigue loading, the load range is 20-100kN, the epoxy resin-steel pipe anchoring has no loosening, and the torque attenuation of the threaded connection part is less than 2%. This shows that the composite bar anchoring module 6 of the device has high anchoring reliability and can maintain stable anchoring performance under long-term fatigue loading, providing a reliable basis for accurate measurement.

[0072] 2. Environmental adaptability test: Under different environmental conditions, the bonding strength attenuation rate measured by the device is low. The bonding strength attenuation rate under standard curing is 0%; the bonding strength attenuation rate after 3000h of 5% NaCl salt spray is 2.7%; and the bonding strength attenuation rate after temperature cycling (-30-60℃) is 3.5%. This shows that the device has good environmental adaptability and can accurately measure the bonding performance between the composite bar 7 and the anchoring material under different environmental conditions.

[0073] 3. Economic comparison: Single test cost: the single test cost of the traditional device is ￥3200, and the single test cost of the device is ￥850. The device greatly reduces the test cost.

[0074] Effective data rate: the effective data rate of the traditional device is 65%, and the effective data rate of the device is 98%. The device can obtain more effective test data, improving the efficiency and reliability of the test.

[0075] Preparation time of test piece: the preparation time of test piece of the traditional device is 7 days (curing), and the preparation time of test piece of the device is 2 hours. The device shortens the preparation time of test piece, improving the test efficiency.

[0076] Therefore, the steel composite bar anchoring interface bonding performance test device has many significant beneficial effects, covering measurement accuracy, operation convenience, structural stability, result reliability, and applicability to composite bars 7, etc. The specific effects are as follows: 1. Measurement accuracy: Directly obtain the real slip amount: the slip amount measured by the traditional drawing test device contains the slip amount between the reinforcement and the anchoring material and the deformation of the reinforcement itself, while the displacement meter 51 in the device directly measures the slip amount of the composite reinforcement 7 relative to the test block fixing module 4. At the same time, the anchoring unit 61 is arranged between the clamp 62 and the composite reinforcement 7, which improves the connection stability between the clamp 62 and the composite reinforcement 7, effectively reduces the slip at the anchoring end, avoids the interference of the deformation of the reinforcement itself on the measurement of the slip amount in the traditional device, and accurately obtains the real slip amount between the reinforcement and the test block fixing module 4 without additional testing of the strain or displacement at the bottom of the reinforcement.

[0077] Reduce measurement error: the overall device structure is reasonable, and each component is accurately positioned. For example, the measurement support 52 is fixed on the test block fixing module 4, and the displacement meter 51 is installed on the measurement support 52. This stable installation method ensures the accuracy of the measurement of the displacement meter 51. Moreover, the steel frame structure 3 provides stable support for each component, reduces the measurement error caused by the device structure and measurement method, and can more accurately reflect the bonding performance between the composite reinforcement 7 and the test block fixing module 4.

[0078] 2. Operation convenience: Easy assembly and disassembly: the connection method between the components of the device is reasonably designed and easy to operate. The top connection assembly 1 and the bottom connection assembly 2 are respectively used to connect the upper end and the lower end of the universal testing machine, and the connection method is simple and direct. The connecting rod 33 of the steel frame structure 3 is connected with the steel frame top plate 31 and the bottom plate by screw connection. This connection method is not only firm, but also convenient for adjusting the height of the working space 8 to adapt to test blocks and test requirements of different sizes. The installation and disassembly of components such as the test block fixing module 4, the displacement measurement assembly 5 and the composite reinforcement anchoring module 6 are also relatively simple, which can save test preparation time and improve work efficiency.

[0079] Simplify the test process: since the device can directly measure the required real slip amount, it is not necessary to additionally test the strain or displacement at the bottom of the reinforcement as in the traditional device, which simplifies the test process. The operator only needs to follow the specified steps to assemble the device, install the test block, adjust the displacement meter 51 and perform the loading test, etc., to complete the test, which reduces the complexity and workload of the operation and reduces the influence of human factors on the test results.

[0080] 3. Structural stability: Stable steel frame structure 3: the steel frame structure 3 is composed of a steel frame top plate 31, a steel frame bottom plate 32 and a connecting rod 33. The screw connection between the connecting rod 33 and the top plate and the bottom plate makes the whole frame structure have high strength and stability. During the test, the steel frame can withstand the pulling force applied by the universal testing machine and will not deform or shake obviously, providing stable foundation support for the test and ensuring the smooth progress of the test.

[0081] Reliable component connection: The test block fixing module 4 is fixed on the steel frame bottom plate 32, the clamp 62 in the composite bar anchoring module 6 is also fixed on the steel frame bottom plate 32, and the connection between the anchoring unit 61 and the composite bar 7 is stable. This reliable connection method ensures that there is no relative movement or separation between the components during the loading process, avoids test errors or safety accidents caused by loose components, and improves the overall stability and safety of the device.

[0082] 4. Reliable results: True reflection of bonding performance: By accurately measuring the actual slip between the composite bar 7 and the test block fixing module 4, and combining with the load value measured by the universal testing machine, the accurate bond-slip relationship curve can be obtained. This true bonding performance data can provide reliable basis for the design, construction and use of steel composite bars 7 in the field of civil engineering, and help to optimize the anchoring method of composite bars 7 and improve the safety of the structure.

[0083] Good repeatability: Due to the stable structure and accurate measurement of the device, consistent test results can be obtained under different test conditions and multiple repeated tests. Good repeatability allows researchers to conduct in-depth research and analysis on the bonding performance of the steel composite bar 7 anchoring interface, compare the influence of different factors such as anchoring material, composite bar 7 specification, loading rate, etc. on the bonding performance, and improve the reliability and scientificity of the research results.

[0084] 5. Applicability to composite bars 7: Adaptable to different types of composite bars 7: The device has strong versatility and can adapt to different types and specifications of steel composite bars 7. Whether it is a composite bar 7 of different diameter, length, or a composite bar 7 composed of different materials, only by adjusting the size of the test block fixing module 4, the specification of the anchoring unit 61 and the clamping distance of the measuring support 52, etc. Parameters, the bonding performance test of the anchoring interface can be carried out, providing an effective test means for various types of steel composite bar 7 products.

[0085] Meet different engineering needs: In the field of civil engineering, different engineering structures have different requirements for the anchoring performance of steel composite bars 7. The device can simulate different engineering environments and use conditions, test the bonding performance of steel composite bars 7 under different anchoring materials and different loading methods, provide targeted data support for engineering design and construction, and meet the actual needs of different engineering.

[0086] The technical means disclosed in the present application are not limited to the technical means disclosed in the above embodiments, and include technical solutions composed of any combination of the above technical features. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements are also considered within the scope of protection of the present application.

Claims

1. A device for testing the bonding performance of steel composite reinforcement anchorage interface, characterized in that, include: Top connecting component (1), the top connecting component (1) is used to connect to the upper end of the universal testing machine; Bottom connecting component (2), the bottom connecting component (2) is used to connect the lower end of the universal testing machine; A steel frame structure (3) includes a steel frame top plate (31) connected to the top connecting component (1), a steel frame bottom plate (32) connected to the bottom connecting component (2), and a connecting rod (33) located between the steel frame top plate (31) and the steel frame bottom plate (32) to form a working space (8) between the steel frame top plate (31) and the steel frame bottom plate (32); Test block fixing module (4), the test block fixing module (4) is located in the working space (8) and fixed to the steel frame base plate (32), the test block fixing module (4) is used to bond with the composite reinforcement (7); The displacement measuring component (5) includes a displacement gauge (51) and a measuring bracket (52). The measuring bracket (52) is fixed on the test block fixing module (4), and the displacement gauge (51) is installed on the measuring bracket (52). The composite reinforcement anchoring module (6) includes an anchoring unit (61) and a clamp (62) for clamping and fixing the composite reinforcement (7). The anchoring unit (61) is fixed to one end of the composite reinforcement (7), and the clamp (62) is fixed to the steel frame base plate (32) for clamping and fixing with the anchoring unit (61). The other end of the composite reinforcement (7) passes through the steel frame base plate (32) and the test block fixing module (4) in sequence, and abuts against the displacement gauge (51).

2. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 1, characterized in that, The test block fixing module (4) has a through hole (41) through which the composite reinforcement (7) passes. The through hole (41) is composed of an unbonded section (411) and a bonded section (412). The unbonded section (411) is located at one end of the through hole (41) near the bottom plate (32) of the steel frame.

3. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 2, characterized in that, The unbonded section (411) is provided with an isolation sleeve (413), the inner diameter of which is larger than the outer diameter of the composite reinforcement (7).

4. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 3, characterized in that, The length of the isolation sleeve (413) is the same as the length of the composite reinforcement (7) extending out of the test block fixing module (4).

5. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 1, characterized in that, The measuring bracket (52) includes: A support base (521) is mounted on the test block fixing module (4); A support beam (522) is mounted on the support base (521); A support column (523) is mounted on the support beam (522); A snap-fit ​​structure (524) is assembled on the support column (523) and is used to snap-fit ​​and fix the displacement gauge (51).

6. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 5, characterized in that, The support base (521) includes a first frame (5211) and a second frame (5212), which are symmetrically fastened together to form a rectangular frame. The support crossbeam (522) includes a first crossbeam (5221) installed on the first frame (5211) and a second crossbeam (5222) installed on the second frame (5212). The first crossbeam (5221) and the second crossbeam (5222) are spaced apart and collinearly arranged. The column (523) includes a first column (5231) mounted on the first crossbeam (5221) and a second column (5232) mounted on the second crossbeam (5222). The snap-fit ​​structure (524) includes a first snap-fit ​​member (5241) and a second snap-fit ​​member (5242) for clamping the displacement gauge (51). The first snap-fit ​​member (5241) is assembled at the end of the first column (5231), and the second snap-fit ​​member (5242) is assembled at the end of the second column (5232).

7. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 1, characterized in that, The clamp (62) has a clamping groove (621) with an internal thread. The anchoring unit (61) is cylindrical with an external thread on its outer side wall. The anchoring unit (61) is threadedly connected to the clamping groove (621). The inner diameter of the anchoring unit (61) is larger than the outer diameter of the composite reinforcement (7). The space between the anchoring unit (61) and the composite reinforcement (7) is filled with a flexible adhesive material (63).

8. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 1, characterized in that, The connecting rod (33) is threadedly connected to the top plate (31) and bottom plate (32) of the steel frame to adjust the height of the workspace (8), which is in the range of 200mm-500mm.

9. The device for testing the bonding performance of steel composite reinforcement anchorage interface according to claim 7, characterized in that, The flexible adhesive material (63) is a silicone sealant or epoxy resin.

10. A method for testing the bonding performance of the anchorage interface of steel composite reinforcement, characterized in that, The steel composite reinforcement anchorage interface bonding performance testing device according to any one of claims 1-9 includes the following steps: Preparation of anchoring material test block: The top of the composite bar (7) extends 20 mm beyond the surface of the prepared anchoring material test block, the bottom is inserted into the anchoring unit (61) and sealed with epoxy resin; Assemble the measuring bracket (52), connect the measuring bracket (52) to the steel frame base plate (32) with multiple sets of bolts, and reserve a certain working space (8); Install displacement measuring assembly (5): Fix the measuring bracket (52) on the anchoring material test block, adjust the snap-fit ​​distance of the snap-fit ​​structure (524) in the measuring bracket (52) so that the probe of the displacement gauge (51) is in vertical contact with the top of the composite reinforcement (7); Connecting the anchoring module: The anchoring unit (61) is threadedly connected to the clamp (62), and the base of the clamp (62) is fixed to the steel frame base plate (32) by bolts; Universal testing machine for docking: The top connecting component (1) is connected to the upper end of the testing machine through the top pin (11), and the bottom connecting component (2) is connected to the lower end of the testing machine through the bottom pin (21); The universal testing machine loads at a rate of ≤20kN / min or 1mm / min, and simultaneously collects the slippage of the displacement gauge (51) and the load value of the universal testing machine. The slippage of the displacement gauge (51) is the displacement of the composite reinforcement (7) relative to the anchoring material test block.

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