Destructive testing device of in-site concrete using anchor bars

Abstract

The present invention relates to an on-site concrete destructive testing device using an anchor bar, which is configured such that an anchor plate embedded within a concrete member and a reaction plate provided on the surface of the concrete member are connected by an anchor bar, and a force applying member is coupled to the front end of the anchor bar at the front of the reaction plate to apply a pulling force to the anchor bar, thereby enabling rapid, accurate, and measurement of concrete strength regardless of concrete age by performing a destructive test on a concrete member cast in the field without a separate core extraction process. The on-site concrete destructive testing device using an anchor bar according to the present invention is intended for measuring the compressive strength of a concrete member cast in the field, and comprises: an anchor plate embedded within the concrete member so as to be spaced apart from the surface of the concrete member; a reaction plate provided at a position corresponding to the anchor plate, spaced apart from the anchor plate and in close contact with the surface of the concrete member, having a through hole formed in the center; an anchor bar, the rear end of which is connected to the anchor plate and the front end of which protrudes toward the reaction plate; and a force applying member coupled to the front end of the anchor bar at the front of the reaction plate to apply a pulling force to the anchor bar. It consists of a separation ring formed in a cylindrical shape with a larger diameter than the anchor plate and reaction plate on the outer front side of the anchor bar and embedded within a concrete member.

Description

Technology Field

[0001] The present invention relates to an on-site concrete destruction test device using an anchor bar, wherein an anchor plate embedded within a concrete member and a reaction plate provided on the surface of the concrete member are connected by an anchor bar, and a force applying member is coupled to the shear of the anchor bar at the front of the reaction plate to apply a pulling force to the anchor bar, thereby enabling rapid, accurate, and measurement of concrete strength regardless of concrete age by performing a destruction test on a concrete member cast on-site without a separate core extraction process. Background Technology

[0003] Concrete is a composite material manufactured by mixing cement, aggregates, and water, and it is influenced by various factors such as the management status of cement and aggregates, ready-mix concrete mixing conditions, transportation methods and time, and pouring and curing conditions. Therefore, to ensure the stability of concrete structures, it is crucial to assess the required strength, durability, watertightness, and uniformity of quality.

[0004] In particular, concrete compressive strength is directly related to the stability of concrete structures, so it is essential to measure it.

[0005] When pouring concrete on-site, concrete quality is managed by producing test specimens for strength measurement from the on-site ready-mix concrete. However, it frequently occurs that the measured values ​​of the specimens differ from those of the actual structure due to differences between the concrete used to produce the specimens and the concrete actually poured, or due to concrete pouring conditions such as on-site water content or curing conditions. In the case of the Incheon apartment site where an underground parking lot collapsed in April 2023, core specimens were taken from the concrete at the collapse site after the accident and destructive tests were performed; the results showed that the strength was measured to be about 30% lower than the design standard strength.

[0006] Therefore, it is important to ensure the stability of the structure by measuring the strength of the concrete actually poured on-site.

[0007] Test methods for measuring the compressive strength of cast-in-place concrete structures include destructive testing and non-destructive testing.

[0008] Destruction testing is a method of verifying compressive strength and other physical properties by taking a concrete core from a concrete structure and then conducting a destructive test in a laboratory (Registered Patent No. 10-1669616, etc.).

[0009] However, since the destructive test requires taking concrete cores while avoiding reinforcing bars embedded within the concrete member, there are limitations on the location and size of the cores to be taken.

[0010] Furthermore, during core extraction, the core specimen itself may be damaged as it is separated from the concrete structure using a core extraction drill, which can affect the core strength. Due to this concern regarding specimen damage during extraction, core extraction is virtually impossible for early-aged concrete before design strength is achieved.

[0011] Furthermore, since core specimens are extracted by fixing a core drill to a concrete member, extraction is difficult in areas where installation is challenging. Additionally, anchoring the core to the surrounding concrete is required to secure the drill, making additional damage inevitable. Moreover, a significant amount of time is required for core extraction, as well as for the subsequent drying and surface treatment of the specimens.

[0012] Non-destructive testing methods include the rebound hardness method using a Schmidt hammer and the ultrasonic method (Registered Patent No. 10-2021039, etc.).

[0013] These non-destructive tests have the advantage of not causing damage to the structure and allowing inspection over a wider area rather than being limited to specific parts. However, they are not recognized as an evaluation method in the Concrete Structural Design Standard (KDS 14 20) because they are less reliable than direct destructive tests. The problem to be solved

[0015] To solve the above-mentioned problems, the present invention aims to provide an on-site concrete fracture testing device using an anchor bar that can measure concrete strength quickly, accurately, and regardless of the concrete age by directly performing a fracture test on a concrete member cast on-site without a separate core extraction process. means of solving the problem

[0017] The present invention, according to a preferred embodiment, provides an on-site concrete destruction test device using an anchor bar for measuring the compressive strength of a concrete member cast in the field, comprising: an anchor plate embedded inside the concrete member so as to be spaced apart from the surface of the concrete member; a reaction plate provided to be spaced apart from the anchor plate at a position corresponding to the anchor plate and in close contact with the surface of the concrete member, with a through hole formed in the center; an anchor bar having a rear end connected to the anchor plate and a front end protruding toward the reaction plate; a force applying member coupled to the front end of the anchor bar at the front of the reaction plate to apply a pulling force to the anchor bar; and a separation ring formed in a cylindrical shape with a diameter larger than that of the anchor plate and the reaction plate on the outer front side of the anchor bar and embedded inside the concrete member, wherein the compressive strength of the concrete between the anchor plate and the reaction plate is measured by the pulling force applied to the anchor bar.

[0018] According to another preferred embodiment, the present invention provides an on-site concrete failure test device using an anchor bar, characterized in that the anchor bar protrudes to the front of the reaction plate by penetrating a through hole of the reaction plate, and the force applying member is a nut fastened to the protruding front end of the anchor bar.

[0019] According to another preferred embodiment, the present invention provides an on-site concrete destruction test device using an anchor bar, characterized in that the anchor bar protrudes to the front of the reaction plate by penetrating a through hole of the reaction plate, and the force applying member is a hydraulic jack coupled to the protruding front end of the anchor bar.

[0020] delete

[0021] According to another preferred embodiment, the present invention provides an on-site concrete destruction test device using an anchor bar, characterized in that a non-attachable tube is provided to surround the anchor bar on the outside of the portion of the anchor bar embedded inside the concrete member.

[0022] According to another preferred embodiment, the present invention provides an on-site concrete destruction test device using an anchor bar, characterized in that a guide groove is formed in the longitudinal direction on one side of the outer surface of the anchor bar, and a guide projection that is inserted into the guide groove is formed protrudingly on the inner surface of the through hole of the reaction plate.

[0023] According to another preferred embodiment, the present invention provides an on-site concrete destruction test device using an anchor bar, characterized in that a supporting protrusion is formed protrudingly on one side of the anchor plate.

[0024] The present invention, according to another preferred embodiment, provides an on-site concrete destruction test device using an anchor bar, characterized in that the anchor bar comprises a bar body connected to the anchor plate and protruding toward the reaction plate, a connecting member provided at the front end of the bar body such that a female screw thread is formed on the inner circumference and the front surface is exposed to the concrete member, and a connecting bolt that is screw-coupled to the front of the connecting member and coupled to the force applying member.

[0025] According to another preferred embodiment, the present invention provides an on-site concrete failure testing device using an anchor bar, characterized in that a receiving groove is formed in the front side concrete member of the anchor bar to expose the front end of the anchor bar, and the force applying member is composed of a connecting part, which penetrates the reaction plate and screw-couples the front end of the anchor bar within the receiving groove, and a rotating part, which is formed with an outer diameter larger than that of the connecting part and is in close contact with the front surface of the reaction plate, wherein the connecting part has an internal screw thread formed on its inner circumference.

[0026] The present invention, according to another preferred embodiment, provides a method for testing the destruction of concrete in a field using the destruction test device, comprising: (a) a step of embedding and installing the anchor plate and anchor bar inside a concrete member and installing a reaction plate at the front of the anchor bar; (b) a step of installing a force applying device at the front of the anchor bar from the front of the reaction plate; (c) a step of pulling out the anchor bar by the force applying device to apply a compressive force to the concrete between the anchor plate and the reaction plate, and calculating the concrete strength by measuring the tensile force of the anchor bar at the time of concrete destruction; (d) a step of removing the concrete between the anchor plate and the reaction plate and the destruction test device; and (e) a step of repairing the space where the destruction test device was removed by pouring non-shrink mortar. Effects of the invention

[0028] According to the present invention, an on-site concrete failure test device using an anchor bar can be provided, wherein an anchor plate embedded inside a concrete member and a reaction plate provided on the surface of the concrete member are connected by an anchor bar, and the device includes a force applying member that is coupled to the front of the anchor bar at the front of the reaction plate and applies a pulling force to the anchor bar.

[0029] Accordingly, since the compressive strength of concrete can be measured by applying a pull-out force to the anchor bar until the concrete between the anchor plate and the reaction plate is destroyed, destructive testing can be performed on cast-in-place concrete members without a separate core sampling process, enabling rapid and accurate inspection.

[0030] In addition, since there is no need to install a core drill, damage to surrounding concrete can be minimized, and field destructive testing of early-aged concrete, where core extraction is impossible, is possible, allowing concrete strength to be measured regardless of the concrete's age. Brief explanation of the drawing

[0032] FIG. 1 is a perspective view illustrating the field concrete destruction test device of the present invention. FIG. 2 is a perspective view illustrating the connection relationship of the field concrete destruction test device of the present invention. FIG. 3 is a perspective view illustrating a destructive testing device installed on a concrete member. FIG. 4 is a cross-sectional perspective view illustrating a destructive testing device installed on a concrete member. FIG. 5 is a cross-sectional perspective view illustrating a destructive testing device fixed to a formwork. FIG. 6 is a perspective view illustrating a state in which a C-ring is coupled to a reaction plate. FIG. 7 is a perspective view illustrating a destructive testing device in which the force applying device is a hydraulic jack. FIG. 8 is a perspective view illustrating the coupling relationship of the destructive testing device shown in FIG. 7. FIG. 9 is a perspective view showing the state in which the destructive testing device of FIG. 7 is installed on a concrete member. FIG. 10 is a perspective view illustrating a destructive testing device equipped with a separation ring. FIG. 11 is a cross-sectional perspective view showing the state in which the destructive testing device of FIG. 10 is installed on a concrete member. FIG. 12 is a cross-sectional perspective view illustrating a destructive testing device equipped with a non-attachable tube. FIG. 13 is a perspective view illustrating a destructive testing device equipped with a guide groove and a guide protrusion. FIG. 14 is a bottom perspective view illustrating an anchor plate equipped with a supporting protrusion. FIG. 15 is a perspective view illustrating the connection relationship of a separable anchor bar. FIG. 16 is a cross-sectional perspective view illustrating the installation state of a destructive test device equipped with a detachable anchor bar of FIG. 15. FIG. 17 is a perspective view illustrating a destructive testing device including a force applying member equipped with a connecting part. FIG. 18 is a cross-sectional perspective view illustrating a state in which a receiving groove is formed in the shear of the anchor bar. FIG. 19 is a cross-sectional perspective view showing the state in which the destructive testing device of FIG. 17 is installed on a concrete member. FIGS. 20 to 24 are drawings illustrating the step-by-step process of the field concrete destruction test method of the present invention. Specific details for implementing the invention

[0033] The present invention will be described in detail below according to the attached drawings and preferred embodiments.

[0035] FIG. 1 is a perspective view illustrating the field concrete destruction test device of the present invention, and FIG. 2 is a perspective view illustrating the connection relationship of the field concrete destruction test device of the present invention. FIG. 3 is a perspective view illustrating the destruction test device installed on a concrete member, and FIG. 4 is a cross-sectional perspective view illustrating the destruction test device installed on a concrete member. FIG. 5 is a cross-sectional perspective view illustrating the destruction test device fixed to a formwork, and FIG. 6 is a perspective view illustrating the state in which a C-ring is coupled to a reaction plate.

[0036] As illustrated in FIGS. 1 to 4, the field concrete destruction test device using the anchor bar of the present invention is for measuring the compressive strength of a concrete member (1) cast on-site and is characterized by comprising: an anchor plate (2) embedded inside the concrete member (1) so as to be spaced apart from the surface of the concrete member (1); a reaction plate (3) provided to be spaced apart from the anchor plate (2) at a position corresponding to the anchor plate (2) and in close contact with the surface of the concrete member (1), having a through hole (31) formed in the center; an anchor bar (4) whose rear end is connected to the anchor plate (2) and whose front end protrudes toward the reaction plate (3); and a force applying member (5) which is coupled to the front end of the anchor bar (4) at the front of the reaction plate (3) and applies a pulling force to the anchor bar (4).

[0037] The present invention is intended to provide an on-site concrete destruction test device using an anchor bar that can perform a destruction test directly on a concrete member (1) cast on-site, thereby measuring the concrete strength quickly, accurately, and regardless of the concrete age.

[0038] The present invention is intended to measure the strength of concrete directly on-site without a separate core extraction process by performing a destructive test directly on a concrete structure.

[0039] The field concrete destruction test device of the present invention is embedded in advance inside a concrete member (1) that is cast on-site during the construction of a concrete structure.

[0040] The above-described destructive test device comprises an anchor plate (2), a reaction plate (3), an anchor bar (4), and a force applying member (5).

[0041] The anchor plate (2) and the reaction plate (3) are provided spaced apart from each other at the same location.

[0042] Specifically, the anchor plate (2) is embedded inside the concrete member (1) so as to be spaced apart from the surface of the concrete member (1), and the reaction plate (3) is provided on the surface of the concrete member (1) at a position corresponding to the anchor plate (2) and spaced apart from the anchor plate (2).

[0043] The anchor plate (2) and the reaction plate (3) are each formed in the shape of a disc, and a virtual concrete specimen in the shape of a cylinder is formed between the anchor plate (2) and the reaction plate (3).

[0044] Considering that concrete stress acts upward and outward at an angle of approximately 45˚ when a pulling force is applied to the anchor plate (2), the anchor plate (2) can be formed with a smaller diameter than the reaction plate (3) (Fig. 4).

[0045] An anchor bar (4) for transmitting pulling force to the anchor plate (2) is provided at the front center of the anchor plate (2).

[0046] It is preferable that the outer surface of the portion where the anchor bar (4) is embedded in the concrete member (1) be formed smoothly without threads so as to minimize stress transfer between the anchor bar (4) and the surrounding concrete when a pulling force is applied to the anchor bar (4).

[0047] The rear end of the anchor bar (4) is connected to the front of the anchor plate (2), and the front end of the anchor bar (4) is configured to face the reaction plate (3).

[0048] The rear end of the anchor bar (4) may be formed integrally with the anchor plate (2), screw-coupled to the anchor plate (2), or connected to the anchor plate (2) by passing through the anchor plate (2) and fastening a separate nut (not shown).

[0049] As illustrated in FIG. 3, the front of the anchor bar (4) can penetrate the reaction plate (3) and protrude to the front of the reaction plate (3).

[0050] To this end, a through hole (31) is formed in the center of the reaction plate (3).

[0051] The anchor bar (4) is installed embedded within the concrete member (1) together with the anchor plate (2), but a portion of the shear length of the anchor bar (4) is not embedded within the concrete member (1) and may be exposed to the front of the reaction plate (3).

[0052] The above reaction plate (3) is installed so that its front surface is exposed to the front surface of the concrete member (1).

[0053] The above reaction plate (3) may be installed such that it is partially or entirely embedded on the front side of the concrete member (1) when the anchor plate (2) and anchor bar (4) are installed. Alternatively, the above reaction plate (3) may be installed separately from the anchor plate (2) and anchor bar (4) on the front side of the concrete member (1) at the test location at the time of the destructive test.

[0054] The destructive testing device of the present invention can be installed in a location without formwork, such as the upper surface of a slab or the upper surface of a beam. In this case, the anchor plate (2) can be fixed by binding it to lower reinforcing bars, etc. Since the surface of the concrete member (1) may be uneven, it is preferable to install the reaction plate (3) in advance so that its entire or partial thickness is embedded within the concrete member (1).

[0055] When formwork (10) is installed, such as on the lower part of a slab, a column or wall, or the side or lower part of a beam, the destructive test device of the present invention can temporarily fix the position of the anchor bar (4) protruding from the front of the reaction plate (3) by passing it through the formwork (10) with a fastening nut (N), etc. (Fig. 5). At this time, the reaction plate (3) may be installed on the outside of the anchor bar (4) in advance, or it may be installed separately before the destructive test after the formwork (10) is removed.

[0056] When the above reaction plate (3) is installed together with the anchor bar (4), a C-ring (311) made of an elastic material such as rubber may be inserted between the anchor bar (4) and the through hole (31) of the reaction plate (3) to fix the position of the reaction plate (3) (Fig. 6 (a) and (b)).

[0057] The destructive testing device of the present invention can be installed embedded within a concrete member (1) during concrete casting on-site. Subsequently, when the time comes for strength evaluation after the concrete has hardened, the anchor bar (4) can be pulled out by connecting a force applying device (5) to the anchor bar (4).

[0058] The above force member (5) is connected to the front end of the anchor bar (4) at the front of the reaction plate (3) and applies a pulling force to the anchor bar (4). At this time, the reaction plate (3) acts as a reaction base that supports the force member (5).

[0059] When the above-mentioned force member (5) is supported on the reaction plate (3) and a pulling force is applied to the anchor bar (4), the anchor plate (2) at the rear end of the anchor bar (4) is pressed toward the reaction plate (3), and a compressive force is applied to the concrete between the anchor plate (2) and the reaction plate (3).

[0060] Pulling force is continuously applied to the anchor bar (4) until the concrete between the anchor plate (2) and the reaction plate (3) is destroyed. At this time, the compressive strength of the concrete can be calculated by connecting a measuring part (8) to the force applying part (5) or the anchor bar (4) to measure the tensile force acting on the anchor bar (4) when the concrete is destroyed (Fig. 8).

[0061] After completing the concrete destruction test, the concrete residue and destruction test equipment within the test site are removed, and the area is repaired by filling with mortar.

[0062] The present invention enables accurate inspection by allowing a destructive test to be performed on an actual constructed concrete member (1). In addition, since there is no need to install a separate core drill, damage to the surrounding concrete at the location of the destructive test can be minimized. Furthermore, since the destructive test is performed immediately on-site without collecting concrete cores, the time required for core collection and the post-processing of the specimen are eliminated, and there is no need to transport the specimen to a laboratory, which significantly shortens the test time and simplifies the procedure. Moreover, on-site destructive testing is possible even on early-aged concrete where core collection is impossible, allowing for early quality verification.

[0064] As shown in FIGS. 1 to 4, the anchor bar (4) protrudes through the through hole (31) of the reaction plate (3) to the front of the reaction plate (3), and the force member (5) may be composed of a nut that is fastened to the protruding front end of the anchor bar (4).

[0065] The above force member (5) may be a nut that is fastened to the front end of the anchor bar (4).

[0066] To this end, the anchor bar (4) has screw threads formed on its shear outer surface, and the shear passes through the through hole (31) of the reaction plate (3) and protrudes to the front of the reaction plate (3). A nut-like force member (5) is fastened to the shear of the anchor bar (4) protruding from the front of the reaction plate (3).

[0067] When the diameter of the through hole (31) of the reaction plate (3) is large, a washer (50) may be installed between the reaction plate (3) and the force applying member (5) to evenly transmit the force acting on the force applying member (5) to the reaction plate (3).

[0068] During the concrete destruction test, the nut, which is the force applying tool (5), can be rotated in a tightening direction to apply pulling force to the anchor bar (4).

[0069] The nut (5) can be rotated using a tool such as a torque wrench.

[0070] The above measuring unit (8) can calculate the concrete compressive strength by measuring the torque applied from the torque wrench.

[0071] If the above-mentioned force member (5) is a nut, the above-mentioned force member (5) can be installed together with the anchor bar (4) by fastening it in advance when installing the destructive test device on the concrete member (1).

[0073] FIG. 7 is a perspective view illustrating a destructive testing device in which the applying force is a hydraulic jack, FIG. 8 is a perspective view illustrating the connection relationship of the destructive testing device illustrated in FIG. 7, and FIG. 9 is a perspective view illustrating the state in which the destructive testing device of FIG. 7 is installed on a concrete member.

[0074] As illustrated in FIGS. 7 to 9, the anchor bar (4) protrudes through the through hole (31) of the reaction plate (3) to the front of the reaction plate (3), and the force applying member (5) may be configured as a hydraulic jack coupled to the protruding front end of the anchor bar (4).

[0075] If the concrete strength is high or the gap between the anchor plate (2) and the reaction plate (3) is large, the anchor bar (4) must be pulled out with a considerable amount of force, but if the force applying member (5) is a nut, there is a limit to the amount of pulling force that can be applied.

[0076] In addition, if the applying member (5) is a nut, a pulling force is applied to the anchor bar (4) by rotating the nut using a torque wrench. The magnitude of the pulling force applied at this time must be calculated using an approximation formula that converts the torque applied to the torque wrench into a pulling force, similar to a general torque wrench test method. However, the conversion formula between torque and pulling force has low accuracy, and calibration of the torque wrench is absolutely necessary.

[0077] Therefore, a hydraulic jack can be used as the force applying device (5) to ensure accuracy of the pulling force while applying sufficient pulling force.

[0078] The above hydraulic jack may be a through-type hydraulic jack having a hollow (501) formed vertically in the center (Fig. 8).

[0079] The front end of the anchor bar (4) penetrates the hollow (501) of the hydraulic jack (5) and protrudes a certain length forward of the force applying member (5), and a fixing nut (51) can be fastened to the front end of the protruding anchor bar (4).

[0080] Afterwards, the above hydraulic jack can be extended to pull out the anchor bar (4) (Fig. 9).

[0081] The tensile force acting on the anchor bar (4) can be measured by directly measuring the hydraulic magnitude of the hydraulic jack or by installing a load cell as a measuring device between the reaction plate (3) and the force applying member (5).

[0083] FIG. 10 is a perspective view illustrating a destructive testing device equipped with a separation ring, and FIG. 11 is a cross-sectional perspective view illustrating the state in which the destructive testing device of FIG. 10 is installed on a concrete member.

[0084] As shown in FIGS. 10 and 11, a separation ring (6) may be provided on the outer front side of the anchor bar (4), formed in a cylindrical shape with a larger diameter than the anchor plate (2) and reaction plate (3), and embedded within the concrete member (1).

[0085] To measure the compressive strength of concrete, a uniaxial compressive force must be applied to the specimen.

[0086] However, the virtual concrete specimen located between the anchor plate (2) and the reaction plate (3) is not provided independently but is integrally connected with the surrounding concrete. Accordingly, when the anchor plate (2) is pressed, a shear force acts between it and the surrounding concrete, and as a result, not only is the stress dispersed, but a restraining effect occurs due to the surrounding concrete, causing the compressive strength to increase, making it difficult to accurately measure the strength.

[0087] Therefore, a separation ring (6) can be installed to separate the concrete at the test location from the surrounding concrete to prevent stress dispersion and to prevent an increase in concrete compressive strength due to the confinement effect, thereby allowing the pure axial compressive strength to be evaluated.

[0088] The above separation ring (6) can be formed in a cylindrical shape having a certain height and provided to surround the concrete between the reaction plate (3) and the anchor plate (2).

[0089] The above separation ring (6) can be formed from a material such as styrofoam or rubber.

[0090] Since the concrete in the core is separated from the surrounding concrete by the separation ring (6), the uniaxial compressive strength can be measured. In addition, since the range in which the concrete is destroyed during the test is limited to within the separation ring (6) by the separation ring (6), the range requiring mortar repair after the test can be reduced.

[0091] Since the above-mentioned separation ring (6) is formed in a cylindrical shape and has a closed cross-section, the concrete may not be properly filled inside the destructive test device due to interference from the separation ring (6) during on-site concrete pouring. Therefore, it is preferable to form the separation ring (6) shorter than the distance between the anchor plate (2) and the reaction plate (3), and to install it on the surface side of the concrete member (1), that is, on the side directly below the reaction plate (3), so that sufficient space is secured between the separation ring (6) and the anchor plate (2).

[0092] If the surface of the concrete member (1) on which the above-mentioned destructive test device is to be installed is an exposed surface where no formwork is installed, the separation ring (6) can be installed by inserting it into the concrete surrounding the destructive test device immediately after pouring concrete around the destructive test device.

[0093] When a formwork (10) is installed on the surface of the concrete member (1), the front end of the separation ring (6) can be attached to the formwork (10) to install it. Alternatively, the separation ring (6) can be formed into a cylindrical shape with a closed front end, so that the front cover portion of the separation ring (6) is fixed between the reaction plate (3) and the formwork (10), and the cover portion can be cut off and removed after the formwork (10) is removed.

[0095] FIG. 12 is a cross-sectional perspective view illustrating a destructive testing device equipped with a non-attachable tube.

[0096] As shown in FIG. 12, a non-attachable tube (7) may be provided on the outside of the anchor bar (4) of the portion embedded inside the concrete member (1) to surround the anchor bar (4).

[0097] The above anchor bar (4) is installed embedded within the concrete member (1). However, if there is an adhesive force between the anchor bar (4) and the concrete, when the anchor bar (4) is pulled out, the pulling force of the anchor bar (4) is not entirely transferred to the anchor plate (2), but is partially transferred to the surrounding concrete due to the adhesive force. In this case, shear force or tensile force acts on the concrete under test, and since the tensile force measured by the measuring part (8) is a value mixed with adhesive force, it becomes difficult to accurately calculate the concrete strength.

[0098] Therefore, to separate the anchor bar (4) from the surrounding concrete and prevent the effect of adhesion between the anchor bar (4) and the concrete, a non-adhesive tube (7) can be placed on the outside of the anchor bar (4).

[0099] Since the anchor bar (4) and the surrounding concrete are completely separated by the above-mentioned non-attached tube (7), the load acting on the anchor bar (4) is fully transferred to the anchor plate (2), allowing the concrete strength to be accurately measured.

[0101] FIG. 13 is a perspective view illustrating a destructive testing device equipped with a guide groove and a guide protrusion.

[0102] As shown in FIG. 13, a guide groove (401) is formed in the longitudinal direction on one side of the outer surface of the anchor bar (4), and a guide projection (32) that is inserted into the guide groove (401) may be formed protrudingly on the inner surface of the through hole (31) of the reaction plate (3).

[0103] If the above-mentioned force member (5) is a nut, the above-mentioned force member (5) can be rotated in a tightening direction to apply a pulling force to the anchor bar (4).

[0104] However, if the above anchor plate (2) is formed in a circular shape, when tightening the force applying member (5), the anchor bar (4) and the anchor plate (2) may rotate together and spin freely due to the frictional force between the force applying member (5) and the anchor bar (4), making it difficult to properly apply pulling force to the anchor bar (4).

[0105] Accordingly, to prevent the anchor bar (4) and anchor plate (2) from rotating freely, a guide groove (401) with a long length in the longitudinal direction is formed on the outer surface of the anchor bar (4), and a guide projection (32) that is inserted into the guide groove (401) can be formed on the inner surface of the through hole (31) of the reaction plate (3) through which the anchor bar (4) passes.

[0106] Accordingly, the guide protrusion (32) engages with the guide groove (401) to prevent the anchor bar (4) from spinning freely when the force member (5) rotates, while allowing the anchor bar (4) to freely deform in the longitudinal direction of the anchor bar (4).

[0108] FIG. 14 is a bottom perspective view illustrating an anchor plate equipped with a supporting protrusion.

[0109] As shown in FIG. 14, a supporting projection (21) may be formed protruding from one side of the anchor plate (2).

[0110] In another embodiment to prevent the anchor bar (4) and anchor plate (2) from spinning freely when the nut (5) is rotated, a support protrusion (21) may be formed protruding from one side of the anchor plate (2).

[0111] The above support protrusion (21) is fixed to the concrete around the anchor plate (2) to prevent the anchor plate (2) from rotating.

[0112] The above support protrusion (21) may be formed on the front surface of the anchor plate (2). However, in this case, since the support protrusion (21) is inserted into the concrete part under test and stress concentration may occur when the anchor bar (4) is pressed, it is preferable that the support protrusion (21) be installed on the back or side surface of the anchor plate (2).

[0113] As shown in FIG. 14, each support protrusion (21) may be formed with a long length and arranged radially in multiple numbers, or may be formed protruding in a spot shape on one side of the anchor plate (2) (not shown).

[0115] FIG. 15 is a perspective view illustrating the connection relationship of a separable anchor bar, and FIG. 16 is a cross-sectional perspective view illustrating the installation state of a destructive test device equipped with the separable anchor bar of FIG. 15.

[0116] As illustrated in FIGS. 15 and 16, the anchor bar (4) may be composed of a bar body (41) connected to the anchor plate (2) and protruding toward the reaction plate (3), a connecting member (42) provided at the front end of the bar body (41) so that the front surface is exposed to the concrete member (1) surface with female screw threads formed on the inner circumference, and a connecting bolt (43) screw-coupled to the front of the connecting member (42) and coupled to the force member (5).

[0117] The destructive testing device of the present invention is embedded within the concrete member (1) after construction of the concrete member (1) and before the destructive test.

[0118] However, if the above anchor bar (4) protrudes to the front of the concrete member (1), there is a risk of worker safety accidents.

[0119] Therefore, the above anchor bar (4) can be configured as a separable type so that there is no part protruding from the front of the concrete member (1) until the destruction test.

[0120] To this end, the anchor bar (4) can be composed of a bar body (41), a joint (42), and a connecting bolt (43).

[0121] The above-mentioned main body (41) and joint (42) are parts embedded inside the concrete member (1).

[0122] The above bar body (41) is configured such that its rear end is fixedly connected to the front center of the anchor plate (2), and its front end faces the reaction plate (3).

[0123] The above joint (42) is provided at the front end of the bar body (41) and can be manufactured integrally with the bar body (41) by welding or the like, or connected by screw connection or the like.

[0124] The above joint (42) has female screw threads formed on its inner surface, so that the open front surface is exposed to the surface of the concrete member (1).

[0125] A connecting bolt (43) is inserted into the front of the joint (42) and screw-coupled.

[0126] Accordingly, until the destructive test, only the bar body (41) and the joint (42) are provided without the connecting bolt (43), so that the anchor bar (4) does not protrude from the front of the concrete member (1). The connecting bolt (43) can be connected to the joint (42) when the destructive test is performed.

[0127] The above force applying member (5) is connected to the above connecting bolt (43) to apply a pulling force.

[0128] The above joint (42) can be used as a coupler for fastening a fastening bolt (or the above connecting bolt (43)) when fixing a destructive test device to a formwork (10).

[0129] The above joint (42) may be formed with an outer diameter larger than that of the bar body (41) or the connecting bolt (43). In this case, when the joint (42) and the bar body (41) are pulled out by the connecting bolt (43), it is preferable that the through hole (31) of the reaction plate (3) be formed larger than the outer diameter of the joint (42) so that the joint (42) does not get caught on the reaction plate (3) (Fig. 16).

[0131] FIG. 17 is a perspective view illustrating a destructive testing device including a load-applying member equipped with a connection part, FIG. 18 is a cross-sectional perspective view illustrating a state in which a receiving groove is formed in the shear of an anchor bar, and FIG. 19 is a cross-sectional perspective view illustrating a state in which the destructive testing device of FIG. 17 is installed on a concrete member.

[0132] As illustrated in FIGS. 17 to 19, a receiving groove (11) is formed in the front side concrete member (1) of the anchor bar (4) to expose the front end of the anchor bar (4), and the force member (5) may be composed of a connecting part (52) in which the front end of the anchor bar (4) is screw-coupled within the receiving groove (11) by penetrating the reaction plate (3) with an internal screw thread formed on its inner surface, and a rotating part (53) formed with an outer diameter larger than that of the connecting part (52) and in close contact with the front surface of the reaction plate (3).

[0133] This is another embodiment for preventing the shear of the anchor bar (4) from protruding to the front of the concrete member (1).

[0134] As shown in FIG. 18, the shear of the anchor bar (4) is installed so that it does not protrude to the front of the concrete member (1), and instead, one side of the force member (5) can be protruded toward the anchor bar (4) to connect the force member (5) to the anchor bar (4) which is received inside the concrete member (1).

[0135] To this end, the above-mentioned force member (5) may be composed of a connecting part (52) formed by a nut to which the anchor bar (4) is connected, and a rotating part (53) that can be rotated from the outside of the reaction plate (3).

[0136] The above connection part (52) is formed with a nut structure having female screw threads formed on its inner surface, so that the front end of the anchor bar (4) is screw-coupled. A receiving groove (11) is formed to a predetermined depth in the front side concrete member (1) of the anchor bar (4) so ​​that the above connection part (52) can be inserted.

[0137] The front end of the anchor bar (4) is exposed in the above receiving groove (11).

[0138] The inner diameter of the receiving groove (11) is formed to be larger than the outer diameter of the connecting part (52), so that the connecting part (52) is received inside the receiving groove (11).

[0139] Since the connecting portion (52) of the above-mentioned force member (5) is inserted into the receiving groove (11) by passing through the through hole (31) of the reaction plate (3), the inner diameter of the through hole (31) is also formed to be larger than the outer diameter of the connecting portion (52).

[0140] A rotating part (53) is formed on the front outer side of the above connecting part (52).

[0141] The above-mentioned rotating part (53) has an outer diameter larger than that of the connecting part (52) and the through hole (31) and is attached to the front surface of the reaction plate (3).

[0142] The above-mentioned rotating part (53) can be formed in a polygonal shape so that a tool such as a torque wrench can be attached.

[0144] FIGS. 20 to 24 are drawings illustrating the step-by-step process of the field concrete destruction test method of the present invention.

[0145] The field concrete destruction test method of the present invention is intended to conduct a destruction test on field concrete using the destruction test device of the present invention described above with reference to FIGS. 1 to 19.

[0146] In the field concrete failure test method of the present invention, first, (a) the anchor plate (2) and the anchor bar (4) are embedded and installed inside the concrete member (1), and a reaction plate (3) is installed at the front of the anchor bar (4) (Fig. 20).

[0147] The above reaction plate (3) may have a through hole (31) formed in the center through which an anchor bar (4) passes, and is installed so that its front surface is exposed to the front surface of the concrete member (1).

[0148] The above anchor plate (2) and anchor bar (4) are provided as a single unit and can be installed by embedding them together inside the concrete member (1).

[0149] The above reaction plate (3) may be installed together with the anchor plate (2) and the anchor bar (4) when they are installed, or it may be installed separately from the anchor plate (2) and the anchor bar (4) later at the front of the anchor bar (4).

[0150] A cylindrical separation ring (6), having a larger diameter than the anchor plate (2) and reaction plate (3), can be embedded and installed within the concrete member (1) on the outer front side of the anchor bar (4).

[0151] And (b) a force member (5) is installed at the front of the anchor bar (4) on the front of the reaction plate (3) (Fig. 21).

[0152] When it is time to evaluate the strength of the concrete, a force applying member (5) is connected to the anchor bar (4).

[0153] Next, (c) the anchor bar (4) is pulled out by the force applying device (5) to apply compressive force to the concrete between the anchor plate (2) and the reaction plate (3), and the tensile force of the anchor bar (4) is measured at the time of concrete failure to calculate the concrete strength (Fig. 22).

[0154] The above force member (5) can be connected to the front of the anchor bar (4) at the front of the reaction plate (3) to apply a pulling force to the anchor bar (4).

[0155] Then, as the anchor plate (2) is pressed toward the reaction plate (3), a compressive force is applied to the concrete between the anchor plate (2) and the reaction plate (3). When the concrete between the anchor plate (2) and the reaction plate (3) is destroyed, the tensile force acting on the anchor bar (4) can be measured to calculate the concrete compressive strength.

[0156] Afterwards, (d) the concrete and the destructive testing device between the anchor plate (2) and the reaction plate (3) are removed (Fig. 23), and (e) non-shrink mortar (M) is poured into the space where the destructive testing device was removed to repair it (Fig. 24).

[0157] That is, after completing the concrete destruction test, the concrete residue and destruction test device within the test site are removed, and then repairs are carried out by filling with non-shrink mortar (M). Explanation of the symbols

[0159] 1: Concrete member 10: Formwork 11: Receiving groove 2: Anchor plate 21: Support protrusion 3: Reaction plate 31: Penetrating hole 311: C ring 32: Guide Stone 4: Anchor Bar 401: Guide Home 41: Babonche 42: Joint 43: Connecting bolt 5: Force tool 50: Washer 501: Hollow 51: Fixing nut 52: Connecting part 53: Rotating part 6: Separator ring 7: Non-attachable tube 8: Measuring section M: Non-shrink mortar N: Fastening nut

Claims

Claim 1 For measuring the compressive strength of a concrete member (1) cast on-site, an anchor plate (2) embedded inside the concrete member (1) so as to be spaced apart from the surface of the concrete member (1); a reaction plate (3) provided to be spaced apart from the anchor plate (2) at a position corresponding to the anchor plate (2) and in close contact with the surface of the concrete member (1), with a through hole (31) formed in the center; an anchor bar (4) whose rear end is connected to the anchor plate (2) and whose front end protrudes toward the reaction plate (3); a force applying member (5) coupled to the front end of the anchor bar (4) at the front of the reaction plate (3) to apply a pulling force to the anchor bar (4); and a separation ring (6) formed in a cylindrical shape with a larger diameter than the anchor plate (2) and the reaction plate (3) on the front side outside of the anchor bar (4) and embedded inside the concrete member (1). A field concrete destruction test device using an anchor bar, characterized by being composed of the above-mentioned anchor bar (4) and measuring the compressive strength of the concrete between the anchor plate (2) and the reaction plate (3) by the pulling force applied to the anchor bar (4). Claim 2 A field concrete destruction test device using an anchor bar, characterized in that, in claim 1, the anchor bar (4) protrudes to the front of the reaction plate (3) by penetrating the through hole (31) of the reaction plate (3), and the force applying member (5) is a nut fastened to the protruding front of the anchor bar (4). Claim 3 A field concrete destruction test device using an anchor bar, characterized in that, in claim 1, the anchor bar (4) protrudes to the front of the reaction plate (3) by penetrating the through hole (31) of the reaction plate (3), and the force applying member (5) is a hydraulic jack coupled to the protruding front of the anchor bar (4). Claim 4 delete Claim 5 A field concrete destruction test device using an anchor bar, characterized in that, in claim 1, a non-attachable tube (7) is provided to surround the anchor bar (4) on the outside of the anchor bar (4) in the portion embedded inside the concrete member (1). Claim 6 A field concrete destruction test device using an anchor bar, characterized in that, in paragraph 2, a guide groove (401) is formed in the longitudinal direction on one side of the outer surface of the anchor bar (4), and a guide projection (32) that is inserted into the guide groove (401) is formed protrudingly on the inner surface of the through hole (31) of the reaction plate (3). Claim 7 A field concrete destruction test device using an anchor bar, characterized in that, in paragraph 2, a supporting protrusion (21) is formed protruding from one side of the anchor plate (2). Claim 8 A field concrete destruction test device using an anchor bar, characterized in that, in claim 1, the anchor bar (4) comprises a bar body (41) connected to the anchor plate (2) and protruding toward the reaction plate (3), a connecting member (42) provided at the front end of the bar body (41) such that a female screw thread is formed on the inner circumference and the front surface is exposed to the concrete member (1), and a connecting bolt (43) screw-coupled to the front of the connecting member (42) and coupled to the force member (5). Claim 9 In paragraph 2, the front side concrete member (1) of the anchor bar (4) has a receiving groove (11) formed therein to expose the front end of the anchor bar (4), and the force member (5) is formed with a female screw thread on its inner surface and is configured to have a connecting part (52) through which the front end of the anchor bar (4) is screw-coupled within the receiving groove (11) and a rotating part (53) formed with an outer diameter larger than that of the connecting part (52) and in close contact with the front surface of the reaction plate (3). Claim 10 A method for performing a destructive test on site concrete using a destructive test device according to any one of claims 1 to 3 and claims 5 to 9, comprising: (a) a step of embedding and installing the anchor plate (2) and anchor bar (4) inside a concrete member (1) and installing a reaction plate (3) at the front of the anchor bar (4); (b) a step of installing a force applying device (5) at the front of the anchor bar (4) from the front of the reaction plate (3); (c) a step of pulling out the anchor bar (4) by the force applying device (5) to apply a compressive force to the concrete between the anchor plate (2) and the reaction plate (3), and calculating the concrete strength by measuring the tensile force of the anchor bar (4) upon concrete failure; (d) a step of removing the concrete and the destructive test device between the anchor plate (2) and the reaction plate (3); and (e) a step of repairing the space where the destructive test device was removed by pouring non-shrink mortar (M). A field concrete destruction test method characterized by being composed of including

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