CN-122016444-A - Steel fiber embedding device and method for steel fiber reinforced 3D printed concrete interface performance

CN122016444ACN 122016444 ACN122016444 ACN 122016444ACN-122016444-A

Abstract

The invention relates to a steel fiber embedding device and method for enhancing the interface performance of 3D printed concrete by steel fibers, wherein an electromagnet cavity is formed in the upper part of an embedder main body, a triangular limiting through groove is formed in one side of the lower part of the embedder main body, the joint surface of the triangular limiting through groove and the embedder main body is a triangular continuous concave-convex fold surface, an iron core in the electromagnet cavity extends downwards into the electromagnet cavity and extends to one side of the triangular limiting through groove, a length adjusting sheet slides up and down along the fold surface and is magnetically connected with the iron core, a plurality of steel fibers are arranged in the triangular limiting through groove and magnetically connected with the iron core, the top ends of the steel fibers are upwards propped under the length adjusting sheet, a steel fiber pressing plate is connected in the triangular limiting through groove through bolts, the steel fiber pressing plate compresses the length adjusting sheet and the steel fibers, clamping units are symmetrically arranged on the lower part of the embedder main body, and the two clamping units clamp the steel fiber embedder on a test piece forming test mold. After the steel fiber embedder is filled with steel fibers, the steel fibers can be inserted into a bottom test piece in a molding test die.

Inventors

WEI DONG
YUAN JIANSONG
ZHANG YU
YANG LIN
TANG JIYU
ZHU HAITANG
FANG DONG
LI ZONGZE
ZHAO LIANGPING
CHEN GANG
QIN DAOTIAN

Assignees

郑州大学
河南工程学院

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (9)

1. The steel fiber embedding device for the steel fiber reinforced 3D printing concrete interface performance comprises a steel fiber embedder and a matched test piece forming test die, and is characterized in that the steel fiber embedder comprises an embedder main body (7), an electromagnet unit containing a plurality of iron cores (18), a length adjusting sheet (28), a steel fiber pressing plate (27) and a clamping unit, wherein an electromagnet chamber (33) is formed in the upper part of the embedder main body (7), a triangular limit through groove (37) is formed in one side of the lower part of the embedder main body, and the joint surface of the triangular limit through groove (37) and the embedder main body (7) is a triangular continuous concave-convex fold surface (371); the electromagnet comprises an electromagnet cavity (33), a length adjusting sheet (28) and a triangular limiting through groove (37), wherein the electromagnet cavity (33) is internally provided with a plurality of iron cores (18) in the electromagnet unit which are uniformly distributed in a shape of a straight line, and the iron cores (18) downwards extend out of the electromagnet cavity (33) and extend to one side of the triangular limiting through groove (37); A plurality of steel fibers (11) are further arranged in the triangular limiting through grooves (37), each steel fiber (11) is magnetically connected with the iron core (18), the top ends of the steel fibers (11) are propped upwards below the length adjusting sheet (28), the steel fiber pressing plates (27) are connected in the triangular limiting through grooves (37) through bolts, the steel fiber pressing plates (27) compress the length adjusting sheet (28) and the plurality of steel fibers (11), the clamping units are symmetrically arranged at two ends of the lower portion of the embedder main body (7), the two clamping units are matched to clamp the steel fiber embedder on the test piece forming test die, and the test piece forming test die comprises a bottom layer test die and a top layer test die.
2. The steel fiber embedding device for steel fiber reinforced 3D printed concrete interface performance according to claim 1, wherein the electromagnet cavity (33) is a rectangular cavity, the top end of the electromagnet cavity (33) upwards penetrates through the embedder main body (7), the top end of the embedder main body (7) is hinged with a cover plate (3) for opening and closing the electromagnet cavity (33), the end face of the cover plate (3) is provided with a handle nest (2) for turning the cover plate (3) by hand, and a locking assembly is arranged between the cover plate (3) and the embedder main body (7) to control the cover plate (3) to turn.
3. The steel fiber embedding device for the steel fiber reinforced 3D printing concrete interface performance according to claim 2, wherein the locking assembly comprises a lock pin slot hole (31), a cover plate lock pin (6) and a cover plate clamping head (16), the lock pin slot hole (31) is formed in the embedder main body (7), the cover plate lock pin (6) is elastically connected in the lock pin slot hole (31) in a sliding way, one end of the cover plate lock pin (6) extends out of the embedder main body (7) and is connected with a pull ring, and the other end of the cover plate lock pin (6) extends out of the lock pin slot hole (31) and extends into an electromagnet cavity (33); The lower part of the cover plate (3) is provided with the cover plate clamping head (16), the cover plate clamping head (16) extends downwards vertically and is connected with a lock tongue at the other end of the cover plate lock pin (6), the embedder main body (7) is provided with an ejection groove (15), the ejection groove (15) is internally provided with an ejection spring (1), the ejection spring (1) is propped against the cover plate (3) in a closed state upwards, and two sides of the upper end of the embedder main body (7) extend outwards horizontally to form a platy embedder handle (20).
4. The steel fiber embedding device for steel fiber reinforced 3D printed concrete interface performance according to claim 1, wherein the electromagnet unit comprises a battery (17), a wire (21), a coil (22), an iron core (18) and a power switch (19), the battery (17) is arranged in an electromagnet cavity (33) through a battery box, the iron core (18) is a rod body, the lower end of the iron core (18) is fixedly arranged in the embedder main body (7) in a penetrating way, the upper end of the iron core (18) extends into the electromagnet cavity (33), the upper end of each iron core (18) is wound with the coil (22), the battery (17), the plurality of coils (22) and the power switch (19) are connected together through the wire (21), and the power switch (19) is arranged on the upper end face of the embedder main body (7).
5. The steel fiber embedding device for steel fiber reinforced 3D printed concrete interface performance according to claim 1, wherein the cross section of the triangular limit through groove (37) is rack-shaped, and a side surface opposite to the fold surface (371) of the triangular limit through groove (37) penetrates through the embedder body (7); The length adjusting piece (28) is a continuously concave-convex bent plate body, the thickness of the length adjusting piece (28) is consistent with the diameter of the steel fiber (11), the steel fiber (11) is arranged at the concave position of the fold surface (371) of the triangular limiting through groove (37), the length adjusting piece (28) and the steel fiber (11) are vertically arranged and vertically abutted, the arrangement length among the plurality of steel fibers (11) is not greater than the length of the length adjusting piece (28), and the steel fiber (11) downwards extends out of the triangular limiting through groove (37).
6. The steel fiber embedding device for the steel fiber reinforced 3D printed concrete interface performance according to claim 1, wherein the steel fiber pressing plate (27) is a long plate body, the middle of the steel fiber pressing plate (27) is thick, the two ends of the steel fiber pressing plate are thin, one side of the middle of the steel fiber pressing plate (27) is triangular continuous concave-convex, a pressing rack (32) is formed, the pressing rack (32) is matched with the length adjusting sheet (28), each protruding position of the pressing rack (32) is inwards sunken to form a triangular rack groove (38), and the rack groove (38) is abutted against the side wall of the steel fiber (11).
7. The steel fiber embedding device for the steel fiber reinforced 3D printed concrete interface performance according to claim 6, wherein a left U-shaped groove (39) is formed in one end of the steel fiber pressing plate (27), a left limit bolt (8) is transversely arranged at one end of the embedder main body (7), the left limit bolt (8) penetrates out of the triangular limit through groove (37) and penetrates through the left U-shaped groove (39) to be connected with a left nut (9), a right U-shaped groove (40) is formed in the other end of the steel fiber pressing plate (27), the length of the left U-shaped groove (39) is smaller than that of the right U-shaped groove (40), a bolt rotating shaft (23) is vertically arranged at the other end of the embedder main body (7), a right limit bolt (24) is transversely arranged on the bolt rotating shaft (23), the right limit bolt (24) penetrates out of the triangular limit through groove (37) and penetrates through the right U-shaped groove (40), a right nut (25) is connected with the left nut (9) and the right nut (25), and the left nut (25) are both butterfly nuts.
8. The steel fiber embedded device for the steel fiber reinforced 3D printing concrete interface performance according to claim 1, wherein the clamping units comprise a base (10) and a limit slide block (36), the limit slide block (36) is elastically connected to the base (10) in a sliding manner, and the limit slide blocks (36) in the two clamping units are matched with a bottom layer test die; The bottom test die and the top test die are arranged symmetrically up and down and are communicated, the top test die comprises two test die side plates (13) and test die partition plates (30), a plurality of test die partition plates (30) are arranged between the two test die side plates (13) at intervals, the bottom test die and the top test die are identical in structure, the bottom test die further comprises a test die bottom plate (14), and a test die bottom plate (14) is arranged between the two test die side plates (13).
9. A method for embedding steel fibers for reinforcing the interfacial properties of 3D printed concrete, characterized in that it is based on an embedding device according to any one of claims 1-8, comprising the steps of: step 1, preparing test molds, namely preparing test piece molding test molds, wherein the test molds comprise a bottom layer test mold and at least one top layer test mold; Step 2, installing steel fibers (11), namely installing a battery (17), starting an electromagnet unit to enable an iron core (18) to generate magnetic force, selecting a length adjusting sheet (28) with proper size according to the specification and the size of the steel fibers (11), adsorbing the length adjusting sheet (28) on the upper part of a triangular limit through groove (37), leveling the surfaces of piled steel fibers (11), adsorbing the steel fibers (11) in the triangular limit through groove (37) in order through the magnetism of the iron core (18), ensuring that the length adjusting sheet (28) and the steel fibers (11) are arranged up and down, and ensuring that the length of the steel fibers (11) exposed outside is half of the whole length, installing a steel fiber pressing plate (27) on a embedder main body (7) through bolts, and tightly pressing the steel fibers (11) and the length adjusting sheet (28) by the steel fibers (11) after screwing the bolts, so as to realize fixation; step 3, preparing a 3D printed concrete bottom test piece (12), namely printing the mixed 3D printed concrete slurry into an assembled bottom test mold through a printer nozzle, placing the bottom test mold on a vibrating table after the bottom test mold is fully built to compact the inside, and leveling the surface by a spatula; Before the test piece is initially set, lifting the embedment device main body (7) by two hands, aiming at the upper surface of the bottom test piece (12), slowly pressing downwards, accurately seating the embedment device main body (7) on the top surface of the bottom test mold under the regulation and control of clamping units at two ends of the lower part of the embedment device main body (7), and then, just embedding 1 ⁄ 2 lengths of all the steel fibers (11) into the upper surface of the bottom test piece (12) to finish the embedding work of the steel fibers (11); Step 5, separating the steel fiber (11) from the embedder main body (7), namely pressing the embedder main body (7) by a left hand, ensuring that the embedder main body (7) does not displace on the upper surface of the bottom layer test piece (12), unscrewing a bolt, and then detaching the steel fiber pressing plate (27), closing an electromagnet unit, and enabling the embedder main body (7) to lose the attractive force on the steel fiber (11), so that the interference on the steel fiber (11) embedded on the surface of the bottom layer test piece (12) is reduced; then the length adjusting sheet (28) is taken down, and the embedment device main body (7) is controlled by both hands to horizontally slide along the bottom layer test piece (12) and gradually move away from the steel fiber (11), so that the embedment device main body (7) is removed; And 6, preparing an integral test piece, namely, before the bottom test piece (12) is finally solidified, installing a top test mold on the bottom test mold, printing concrete slurry which is the same as the bottom test piece (12) in the top test mold, leveling the upper surface by a spatula after the concrete slurry is fully built, and forming the integral 3D printed concrete test piece for testing and evaluating the bonding performance of the 3D printed concrete interface layer.

Description

Steel fiber embedding device and method for steel fiber reinforced 3D printed concrete interface performance Technical Field The invention relates to the technical field of intelligent construction, in particular to a steel fiber embedding device and method for steel fiber reinforced 3D printed concrete interface performance. Background The 3D printing concrete technology is used as an emerging digital construction mode, has the remarkable advantages of high intelligent degree, high flexibility, free forming, template and labor saving and the like, and has great application potential in the fields of complex structure construction, emergency building, personalized construction and the like. However, 3D printed concrete requires layered modeling, and it is the process characteristics of its layer-by-layer stacking that result in a number of weakened inter-layer interfaces inside the printed member. These interfaces are weak links of the printed structure, and their mechanical properties, in particular tensile and shear properties, are far lower than those of the concrete body, severely restricting the integrity, durability and bearing capacity of the printed components, and are one of the key technical bottlenecks that hamper the large-scale application of 3D printed concrete technology in the load-bearing structure. Therefore, in the prior art, steel fibers are directionally arranged in an interface layer to improve the technical path of the interface performance between layers, and the practice proves that the effect is obvious. In short, by arranging the steel fibers in the interlayer interface of the printed concrete, the bonding performance of the interlayer interface can be improved, and the mechanical property of the whole printed concrete can be improved. But the improvement effect may also vary depending on various factors such as the type of steel fiber, geometric parameters such as length and aspect ratio, and the like, the depth of embedment and spacing, and the like, particularly the depth of embedment and spacing. In order to reasonably select the type of the steel fiber and scientifically evaluate the optimal combination of the steel fiber and the 3D printing concrete material and improve the service performance of the structure, the mechanical performance of the 3D printing concrete with the steel fiber embedded in the interface layer is required to be effectively tested, but a special device and a test method for systematically and quantitatively evaluating the interlayer interface performance improvement effect of the steel fiber under the 3D printing process condition are not available at present. In the past, when embedding steel fiber, through manual hand insertion, but this operation is not standard, and steel fiber insertion depth and interval are difficult to prepare to control, and steel fiber can also skew, is unfavorable for doing work. The embedded regularity of the steel fibers can exert the bonding performance between the steel fibers and the concrete to the greatest extent, and the tensile performance of the interface layer can be effectively improved. Publication No. CN217424952U discloses a test device for accurately controlling the embedding depth of steel fibers, which can accurately control the insertion depth of the steel fibers and the distance between adjacent steel fibers, but only one steel fiber can be inserted at a time when the test device is used, and the operation flow is complex when a plurality of steel fibers are inserted. Therefore, the invention develops the steel fiber embedder which accurately embeds the steel fibers at the interlayer interface of the test piece by simulating the 3D printing process flow, the device can effectively and conveniently control the embedment depth, the steel fiber spacing and other simulation parameters, and realize the standardized test of the bonding performance of the 3D printing concrete interface with the steel fibers distributed among the layers, thereby providing reliable experimental basis and technical support for optimizing the raw material proportion, improving the printing process and improving the overall performance of the 3D printing concrete structure. Disclosure of Invention The invention aims to solve the problems of nonstandard embedding and complicated embedding operation of steel fibers in the aspect of evaluating the interface performance of steel fiber reinforced 3D printed concrete, and provides the steel fiber embedding device and method for the interface performance of the steel fiber reinforced 3D printed concrete, which effectively realize the directional arrangement of the steel fibers, accurately control the embedding depth and the spacing, improve the embedding standardization, simultaneously can be used for embedding the steel fibers in batches, avoid repeated operation in the past and improve the embedding efficiency of the steel fibers. In order to achieve the above purpose, the technical schem