Pre-pressing mold for preparing axial tensile concrete test piece and test piece forming method

Abstract

The invention discloses a pre-pressing mold for preparing an axial tensile concrete test piece and a test piece forming method, and relates to the technical field of civil engineering, and the pre-pressing mold comprises an upper mold and a lower mold; the lower mold comprises a bottom plate and a side wall surrounding the bottom plate, and the side wall and the bottom plate jointly define a mold cavity used for containing concrete; the upper mold is detachably covered on the lower mold so as to seal the mold cavity; the upper mold is provided with at least one slurry discharging and exhausting channel penetrating through a body of the upper mold, and the slurry discharging and exhausting channel is used for discharging gas and redundant slurry in the mold cavity and the concrete base body in the pressurizing process; a lateral limiting mechanism is arranged on the outer side of the side enclosure wall of the lower die and used for restraining the side enclosure wall from expanding outwards and deforming when the side enclosure wall bears internal high pressure. The ultra-high performance concrete is prepared by using a pre-pressing technology, and the axial tensile strength of a concrete test piece can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of civil engineering, in particular to a pre-pressing mold for preparing an axial tensile concrete test piece and a test piece forming method. BACKGROUND

[0002] As the most widely used building material in the world, the concrete has the characteristics of high compressive strength and low tensile strength, which has been the key weakness restricting the structural performance. At present, the traditional concrete preparation usually changes the raw material selection, the mix proportion, the water-cement ratio and the like to improve the axial tensile strength of the concrete, however, the axial tensile strength of the concrete test piece prepared by the existing concrete test piece mold is limited, so that a new material with higher performance cannot be researched, and the pre-pressing technology is used to prepare the concrete and the pre-pressing mold of the axial tensile test piece is designed. SUMMARY

[0003] The present application aims to provide a pre-pressing mold for preparing an axial tensile concrete test piece and a test piece forming method to solve the problems existing in the prior art and improve the axial tensile strength of the concrete test piece, which is helpful to research a new material with better performance.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions: The present application provides a pre-pressing mold for preparing an axial tensile concrete test piece, which comprises an upper mold and a lower mold. The lower mold comprises a bottom plate and a side wall surrounding the bottom plate, and the side wall and the bottom plate jointly define a mold cavity for accommodating concrete. The upper mold is detachably covered on the lower mold to close the mold cavity. At least two through-passage channels for discharging slurry and gas are formed on the upper surface of the upper mold, and the through-passage channels are used to discharge the gas and the excess slurry in the mold cavity during the pressurization process. A lateral limiting mechanism is arranged on the outer side of the side wall of the lower mold to inhibit the outward expansion deformation of the side wall when the internal high pressure is borne.

[0005] Preferably, a drainage groove is formed on the upper surface of the upper mold and communicates with the outlet of the through-passage channel, and the drainage groove extends to the edge of the upper mold.

[0006] Preferably, a slurry discharge channel is further arranged on the side wall, and the slurry discharge channel is in the shape of a horn mouth, and the inner hole cross-sectional area of the slurry discharge channel close to the mold cavity is smaller than the outer hole cross-sectional area of the slurry discharge channel away from the mold cavity.

[0007] Preferably, the lateral limiting mechanism comprises a plurality of positioning blocks fixedly arranged on the bottom plate, and the positioning blocks abut against the outer wall of the side wall.

[0008] Preferably, the side wall is detachably fixedly connected with the bottom plate through a first fastening assembly. The first fastening assembly comprises an ear plate arranged outside the side wall, a bolt penetrating through the ear plate, and a threaded hole arranged on the bottom plate and matched with the bolt.

[0009] Preferably, the upper die and the lower die are detachably fixedly connected through a second fastening assembly; the second fastening assembly comprises a plurality of large high-strength bolts of M20 or above.

[0010] Preferably, the side wall comprises two first side plates and two second side plates. The inner side walls of the two second side plates are provided with clamping grooves extending in the vertical direction; the end portions of the two first side plates can be embedded into the clamping grooves.

[0011] Preferably, the two second side plates are fixedly connected with each other through a third fastening assembly; the third fastening assembly comprises a bolt-nut pair penetrating through the two second side plates.

[0012] Preferably, the upper die comprises an upper cover plate and a pressing block fixedly connected to the lower surface of the upper cover plate. When the upper die is closed, the pressing block extends into the mold cavity, and the cross-sectional shape of the pressing block is matched with the cross-sectional shape of the mold cavity; the slurry exhaust passage penetrates through the upper cover plate and the pressing block.

[0013] The application further provides a test piece forming method using the pre-pressing mold, comprising the following steps: Injecting concrete into the mold cavity of the lower die, and the injection amount is higher than the rated height of the mold cavity; Closing the upper die on the lower die; Starting the press to apply pressure to the upper die until the pressure value reaches a predetermined target pressure; in this process, the excess gas and slurry in the mold cavity and the concrete matrix are forcedly discharged through the slurry exhaust passage and / or the slurry discharge passage; In the state of maintaining the pressure of the press, fastening the second fastening assembly to lock the upper die and the lower die as a whole; Removing the mold, and allowing the concrete in the mold cavity to be continuously pressed under the constraint of the mold; After curing for a specified time, removing the mold to obtain the axial tensile concrete test piece.

[0014] The application has the following technical effects compared with the prior art: First, by opening the slurry exhaust passage in the upper mold, the air in the mold cavity can be quickly discharged at the initial stage of pressurization, avoiding the formation of concrete defects caused by residual gas; when the pressure gradually increases, the excess cement slurry can be orderly discharged. This process not only avoids the pressure peak or sealing failure caused by poor discharge, but more importantly, it forcibly reduces the water-cement ratio of the concrete, making the microstructure extremely dense, thereby macroscopically improving the tensile strength, ductility and toughness of the concrete, and successfully preparing ultra-high performance concrete specimens.

[0015] Second, since the upper mold and the lower mold are both made of high-strength steel with a thickness of not less than 20mm, they together form a high-stiffness rigid pressure-bearing body. This structure can effectively resist internal pressures up to 12MPa or even higher, and during the entire pre-pressing and pressure-maintaining process, the mold itself will not deform plastically or break, thereby strictly ensuring the dimensional accuracy and shape integrity of the final formed concrete specimen, providing a reliable and standardized sample for subsequent axial tensile tests, and further developing new materials with better performance.

[0016] Third, the lateral limiting mechanism arranged on the outer side of the side wall of the lower mold can directly and effectively offset the lateral expansion stress generated by the concrete under high pressure, preventing the side wall from moving outward. This design completely solves the technical problem of traditional molds that are prone to "bulging" or even bursting under high pressure, not only ensuring the safety and durability of the mold itself, but more importantly, it ensures that the applied pressure is effectively and vertically transmitted to the interior of the concrete and forms a confining pressure dense concrete matrix, rather than being consumed in overcoming the deformation of the mold, thereby enabling the pre-pressing process to be stable and reliable.

[0017] In summary, the mold has a strong pressure-bearing capacity, efficient discharge function and reliable lateral constraint, which are organically integrated into one, successfully achieving pre-pressing and strengthening of the concrete, and further producing specimens with high axial tensile strength, providing essential equipment support for the research and application of ultra-high performance concrete. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 The structure of the pre-pressing mold for preparing axial tensile concrete specimens in the embodiments of the present application is shown in the separated state of the upper mold and the lower mold. Figure 2is a top view of the upper mold; Figure 3 is a bottom view of the upper mold; Figure 4 is a side view in the width direction of the upper mold; Figure 5 is a side view in the length direction of the upper mold; Figure 6 is a top view of the lower mold; Figure 7 is a side view in the width direction of the lower mold; In the figure: 1-upper mold; 2-lower mold; 11-pile discharging and exhausting passage; 12-drainage groove; 13-bolt for connecting upper cover plate and pressing block; 14-bolt for connecting upper cover plate and bottom plate; 15-upper cover plate; 16-pressing block; 21-bottom plate; 22-first side plate; 23-second side plate; 24-ear plate; 25-positioning block; 26-bolt for connecting two second side plates; 27-side block. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0021] The present application aims to provide a pre-pressing mold for preparing an axially stretched concrete test piece and a test piece forming method, so as to solve the problems in the prior art and improve the axial tensile resistance of the concrete test piece.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The embodiments of the present application will be described below with reference to Figures 1 to 7 .

[0024] Embodiment One The application provides a pre-pressing mold for preparing an axially stretched concrete test piece, which is used for preparing the test piece and comprises an upper mold 1 and a lower mold 2; the lower mold 2 comprises a bottom plate 21 and a side wall surrounding the bottom plate 21, and the side wall and the bottom plate 21 jointly define a mold cavity for accommodating concrete; the upper mold 1 is detachably covered on the lower mold 2 to close the mold cavity; at least two through-type slurry exhaust channels 11 are formed on the upper mold 1 and used for exhausting gas and excess slurry in the mold cavity and the concrete matrix during the pressurizing process; and a lateral limiting mechanism is arranged on the outer side of the side wall of the lower mold 2 and used for inhibiting the outward expansion deformation of the side wall when the internal high pressure is borne.

[0025] The mold has the advantages that the pressure bearing capacity is high, the exhaust function is efficient, and the lateral constraint is reliable, the concrete is successfully pre-pressurized, and the test piece with high axial tensile strength is prepared, and the mold provides important basic equipment support for the research and application of ultra-high performance concrete.

[0026] In some embodiments, the upper surface of the upper mold 1 is provided with drainage grooves 12 in communication with the outlets of the slurry exhaust channels 11, and the drainage grooves 12 extend to the edges of the upper mold 1.

[0027] During the pressurizing process, the drainage grooves 12 are used to avoid the phenomenon that the fluid cannot flow out due to the fact that the pressure end of the press machine presses the outlets of the slurry exhaust channels 11, and in addition, after the excess slurry in the concrete is extruded and flows out from the slurry exhaust channels 11, the slurry is guided to the specific positions of the edges of the upper mold 1 through the drainage grooves 12, so that the outflowing slurry can be conveniently concentrated and treated, and the treatment difficulty is reduced.

[0028] In some examples, the slurry exhaust channels 11 are preferably circular holes arranged equidistantly along the length direction center line of the upper mold 1, and each channel corresponds to a drainage groove 12, the outlet of the channel is located at the bottom of the drainage groove 12, and the drainage groove 12 extends along the width direction of the upper mold 1.

[0029] In some examples, the slurry exhaust channels 11 extend along the thickness direction of the upper mold 1 and penetrate the upper mold 1.

[0030] In some embodiments, the side wall is further provided with a slurry exhaust channel; the slurry exhaust channel is in the shape of a flared mouth, the inner side hole close to the mold cavity has a smaller cross-sectional area than the outer side hole away from the mold cavity.

[0031] In this embodiment, when the press exerts pressure on the concrete in the mold, the excess cement paste is squeezed into the small inner opening of the slurry discharge channel under high pressure. Due to the size and structure of the trumpet mouth, the cement mortar gradually and slowly passes through the channel and is discharged from the large outer opening. This design perfectly solves the problem of blockage that often occurs during high-pressure slurry discharge without causing excessive water loss in the concrete, which in turn affects the hydration rate and strength of the concrete. It is one of the key structures that ensures the success of the pre-pressing preparation technology and enables the concrete to achieve ultra-high performance.

[0032] In some examples, the slurry discharge channel is provided at the bottom of the side plate, i.e., a groove is formed at the bottom edge of the side plate, and the groove and the upper surface of the bottom plate together enclose the slurry discharge channel.

[0033] In some examples, the trumpet mouth is designed with a precise inclination. Specifically, the inner opening near the mold cavity is slightly higher than the outer opening away from the mold cavity, and the inclination is preferably 3% (i.e., a 3mm drop per 100mm length). This angle design is to facilitate the slurry squeezed into the channel under pressure, which will be affected by the component force of its own gravity in addition to the outward pressure, and will flow outward, achieving double driving of pressure and gravity, making the discharge more thorough and efficient.

[0034] In some embodiments, the lateral limiting mechanism is four positioning blocks 25 fixedly provided on the bottom plate 21, which abut against the outer wall of the side wall.

[0035] In this embodiment, when the mold is subjected to an internal pressure of up to 12MPa, the concrete will generate a large lateral expansion force due to the pressure, which will directly act on the side wall. In this embodiment, the positioning block 25 serves as a rigid, non-cushioned mechanical limiting point, and its contact area with the side plate effectively transmits the above-mentioned lateral force directly to the foundation bottom plate 21, and then to the press bed by the bottom plate 21. This design successfully limits the outward movement ("bulging" deformation) of the side wall to any extent, ensuring that the mold cavity still maintains good dimensional stability under high pressure, which is a prerequisite for successful implementation of the pre-pressing preparation technology and ensuring uniform pressure on the concrete.

[0036] In some examples, the positioning block 25 is preferably a high-strength metal block (such as 45 steel), which is fixedly welded to the bottom of the bottom plate 21 to ensure that it can withstand a large lateral thrust.

[0037] In some examples, the inner side of the positioning block 25 is precisely machined to tightly fit (abut) the outer wall of the side wall, with almost no gap between them. The height of the positioning block 25 is preferably 10mm, which can provide sufficient limiting support without occupying too much internal space of the mold or affecting the operation.

[0038] In some embodiments, the side wall is detachably fixedly connected with the bottom plate 21 through a first fastening assembly; the first fastening assembly comprises an ear plate M24 arranged on the outer side of the side wall, a bolt passing through the ear plate M24, and a threaded hole arranged on the bottom plate 21 and matched with the bolt.

[0039] The way in which the side wall in this embodiment is fixed on the bottom plate 21 is beneficial to subsequent stripping.

[0040] Specifically, two or four ear plates 24 are welded on the lower part of the outer side wall of the first side plate 22 perpendicularly to the plate surface. The ear plates 24 are preferably made of the same material as the side plate (e.g., 45 steel) and have a thickness of 20 mm. Smooth bolt through holes are formed on the ear plates 24, and the diameter of the holes is slightly larger than the diameter of the screw rod of the matched bolt, so that the bolt can freely pass through.

[0041] The threaded hole is arranged on the bottom plate 21 at a position accurately aligned with the bolt through hole on the ear plate 24 and is processed into an internal threaded hole (i.e., a threaded hole). The depth and thread specification of the threaded hole are matched with the selected bolt.

[0042] During installation, the side plate is placed at the predetermined installation position of the bottom plate 21, with the outer side wall abutting against the positioning block 25. At this time, the ear plate 24 on the side plate is located above the bottom plate 21, and the bolt through hole on the ear plate 24 is aligned with the threaded hole on the bottom plate 21. The screw rod of the bolt is passed through the through hole of the ear plate 24 and is screwed into the threaded hole of the bottom plate 21. The bolt is tightened using a wrench, and the clamping force generated thereby firmly presses the side plate against the bottom plate 21 and the positioning block 25, completing the fixation and keeping the concrete continuously under pressure.

[0043] In some embodiments, the upper mold 1 and the lower mold 2 are detachably fixedly connected through a second fastening assembly; the second fastening assembly comprises a plurality of M20 and above large high-strength bolts.

[0044] In this embodiment, after the press reaches the target pressure (e.g., 12 MPa), the upper mold 1 and the lower mold 2 are rigidly locked as a whole structure by uniformly tightening the large high-strength bolts in a diagonal and symmetrical manner. This structure can replace the press and passively maintain the concrete in the mold cavity in a high-pressure state at all times, which is the key to realizing the continuous pressure compaction of the concrete and ultimately obtaining the ultra-high performance concrete. The relatively large pre-tightening force ensures that the mold continuously extrudes the excess water and gas inside the concrete matrix during the pressure maintaining period, making the fibers and the concrete matrix more closely, and thus improving the tensile strength of the concrete.

[0045] It can be understood that the upper cover plate 15 constituting the upper mold 1 and the bottom plate 21 constituting the lower mold 2 both have edges protruding from the mold cavity, and the edges of the upper cover plate 15 and the bottom plate 21 are provided with smooth holes and threaded holes to achieve the purpose of connecting the upper mold 1 and the lower mold 2 through bolts.

[0046] In some embodiments, the side wall is formed by two first side plates 22 and two second side plates 23. The inner side wall of the second side plates 23 is provided with a clamping groove extending in the vertical direction, and the end of the first side plate 22 can be embedded in the clamping groove. It can be understood that near the two ends of the inner side wall of each second side plate 23, a clamping groove is formed by milling. The clamping groove extends in the entire height direction (vertical direction) of the second side plate 23, forming a continuous "U"-shaped groove (20 mm wide).

[0047] This embodiment effectively suppresses the relative displacement and separation between the side walls. Specifically, under the action of high pressure inside the concrete, there is a tendency for the side walls to separate from each other. In this embodiment, the clamping groove structure forms a three-dimensional mechanical interlocking, which not only limits the movement of the short wall relative to the long wall in the vertical direction, but also limits the movement of the short wall relative to the long wall in the in-plane direction of the mold (i.e., the front-back-left-right direction of the horizontal plane), thereby ensuring the stability of the mold cavity geometry under high pressure.

[0048] In some examples, due to the clamping groove, a positioning block 25 can be provided on the bottom plate 21 outside the first side plate 22.

[0049] In some embodiments, the two second side plates 23 are pulled and fixed relative to each other by a third fastening assembly. The third fastening assembly includes a bolt-nut pair passing through the two second side plates 23.

[0050] In this embodiment, the third fastening assembly ensures the structural integrity and dimensional stability of the mold under high pressure. During the pre-pressing process, the concrete inside is subjected to a pressure of 12 MPa, and this pressure is transmitted to the surrounding of the mold, generating a lateral expansion force that tries to push the two oppositely arranged second side plates 23 outward. The third fastening assembly actively pulls the two second side plates 23 towards the center of the test piece by a large mechanical tension generated by the bolt-nut pair, effectively counteracting the tension that tends to separate the side plates. This design changes the two side plates that can be independently stressed into a common stress whole frame, greatly enhancing the rigidity and anti-deformation ability of the mold as a whole, avoiding leakage or irreversible "bulging" deformation at the joint of the side plates due to pressure, and providing a solid structural guarantee for the successful implementation of the pre-pressing preparation technology.

[0051] In some examples, the bolt-nut pair preferably adopts a high-strength hexagonal bolt and a matching high-strength nut (e.g., M16 bolt of performance grade 8.8 or above). During assembly, the shank of the bolt is sequentially inserted through the light hole at the corresponding position on the two opposite second side plates 23, and then the nut is screwed at the end of the shank. The nut is symmetrically and batched tightened using a torque wrench at a predetermined torque value (e.g., 150 N·m), thereby generating a uniform and large tension force between the two second side plates 23, so that they are tightly fixed together. This structure is not only crucial when pressurized, but also facilitates the disassembly of the mold: after pre-pressing is completed, the nut is unscrewed, and the side plates are easily separated, and the concrete test piece is removed.

[0052] In some embodiments, the upper mold 1 includes an upper cover plate 15 and a pressing block 16 fixedly connected to the lower surface of the upper cover plate 15; when the mold is closed, the pressing block 16 extends into the mold cavity, and the cross-sectional shape of the pressing block 16 is adapted to the cross-sectional shape of the mold cavity; the discharge channel 11 penetrates the upper cover plate 15 and the pressing block 16.

[0053] In addition, the inner side of the second side plate 23 is also fixed with a side block 27, and the side block 27 and the second side plate 23 are fixed by bolts, and the pressing block 16 and the upper cover plate 15 are also fixed by bolts.

[0054] It can be understood that the side block 27 and the pressing block 16 are present to make a test piece in the shape of a "dog bone".

[0055] As shown in the figure, the upper cover plate 15 and the pressing block 16 are connected by the bolt 13 for connecting the upper cover plate and the pressing block, the two second side plates 23 are connected by the bolt 26 for connecting the two second side plates, and the upper cover plate 15 and the bottom plate 21 are connected by the bolt 14 for connecting the upper cover plate and the bottom plate.

[0056] Among them, the bolt 26 for connecting the two second side plates and the bolt 14 for connecting the upper cover plate and the bottom plate are both M24 bolts. The bolt 13 for connecting the upper cover plate and the pressing block, the bolt for connecting the side block 27 and the second side plate, and the bolt for connecting the ear plate 24 and the bottom plate 21 are all M16 bolts.

[0057] It should be noted that when disassembling the mold, the side block 27 does not need to be disassembled, and the upper cover plate 15 and the pressing block 16 do not need to be disassembled.

[0058] In some embodiments, the thickness of the upper cover plate, the bottom plate, and the side plate is 20 mm.

[0059] Embodiment Two The present application also provides a test piece forming method, which uses the pre-pressing mold in the above embodiments, and includes the following steps: The concrete is injected into the mold cavity of the lower mold 2, and the injection amount is higher than the rated height of the mold cavity, i.e., the standard height of the concrete test piece. In some examples, the concrete amount is 5mm-20mm higher than the given concrete test piece size. That is, the height of the mold cavity in the first embodiment is higher than the height of the concrete test piece by more than 20mm, for example, the mold height can be 100mm, 60mm, 50mm or higher.

[0060] The upper mold 1 is closed on the lower mold 2. The press is started to apply pressure to the upper mold 1 until the pressure value reaches the predetermined target pressure, for example, 12MPa. During this process, the excess gas and slurry in the mold cavity and the concrete matrix are forced out through the slurry and gas discharge channel 11 or the slurry discharge channel. In the state of maintaining the pressure of the press, the second fastening assembly is tightened to lock the upper mold 1 and the lower mold 2 as a whole. The mold is removed, and the concrete in the mold cavity is continuously subjected to pressure under the constraint of the mold. After curing for a specified time, the mold is removed and the axial tensile concrete test piece is obtained.

[0061] This embodiment has all the advantages of the above-mentioned first embodiment, which will not be repeated here.

[0062] In some examples, fibers are mixed into the concrete and the fibers are pre-pressed and compacted to contact the matrix, thereby enhancing the axial tensile properties of the concrete.

[0063] The present application prepares ultra-high performance concrete test pieces by pre-pressing technology, which improves the tensile strength of the concrete test pieces. This helps to develop new technologies and new materials to guide the production of concrete parts in actual engineering, and new materials are obtained through new technologies, which are used for important structures. Improving the tensile strength can significantly reduce the risk of cracking caused by shrinkage, temperature change or load, and at the same time, improve the durability of concrete. Under the action of strong dynamic load, higher tensile strength can effectively absorb external energy, thereby reducing the damage degree of building structure and ensuring the safety of personnel and equipment.

[0064] The principles and implementation modes of the present application are described by applying specific examples. The above examples are only used to help understand the method and core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A pre-compression mold for preparing axially tensile concrete specimens, characterized in that, Including the upper mold and the lower mold; The lower mold includes a base plate and side walls surrounding the base plate, the side walls and the base plate together defining a mold cavity for receiving concrete; The upper mold is detachably fitted onto the lower mold to close the mold cavity; The upper mold is provided with at least two slurry discharge and venting channels that penetrate its body. The slurry discharge and venting channels are used to discharge gas and excess slurry from the mold cavity and concrete matrix during the pressurization process. The side wall of the lower mold is provided with a lateral limiting mechanism to prevent the side wall from expanding and deforming outward when subjected to internal high pressure.

2. The pre-compression mold according to claim 1, characterized in that, The upper surface of the upper mold is provided with a flow-guiding groove that communicates with the outlet of the slurry discharge and exhaust channel, and the flow-guiding groove extends to the edge of the upper mold.

3. The pre-compression mold according to claim 1, characterized in that, The side wall is also provided with a slurry discharge channel; the slurry discharge channel is funnel-shaped, and the cross-sectional area of ​​its inner hole near the mold cavity is smaller than the cross-sectional area of ​​its outer hole away from the mold cavity.

4. The pre-compression mold according to claim 1, characterized in that, The lateral limiting mechanism consists of multiple positioning blocks fixedly mounted on the base plate, and the positioning blocks abut against the outer wall of the side enclosure.

5. The pre-compression mold according to claim 1 or 4, characterized in that, The side wall is detachably fixed to the base plate by a first fastening assembly; The first fastening assembly includes an ear plate disposed on the outer side of the side wall, a bolt passing through the ear plate, and a threaded hole disposed on the base plate that mates with the bolt.

6. The pre-compression mold according to claim 1, characterized in that, The upper mold and the lower mold are detachably fixedly connected by a second fastening assembly; the second fastening assembly includes multiple large high-strength bolts of M20 and above.

7. The pre-compression mold according to claim 1, characterized in that, The side wall is formed by two first side panels and two second side panels. The inner walls of the two second side plates are provided with slots extending in a vertical direction; the ends of the two first side plates can be inserted into the slots.

8. The pre-compression mold according to claim 7, characterized in that, The two second side plates are fastened together by a third fastening assembly; the third fastening assembly includes a bolt and nut pair passing through the two second side plates.

9. The pre-compression mold according to claim 1, characterized in that, The upper mold includes an upper cover plate and a pressure block fixedly connected to the lower surface of the upper cover plate; When the upper mold is closed, the pressure block extends into the mold cavity, and its cross-sectional shape is adapted to the cross-section of the mold cavity; the slurry discharge and venting channel passes through the upper cover plate and the pressure block.

10. A method for molding a specimen, characterized in that, Using the pre-compression mold according to any one of claims 1-9, the process includes the following steps: Concrete is injected into the cavity of the lower mold, with the injection volume exceeding the rated height of the cavity; The upper mold is then placed over the lower mold. The press is started to apply pressure to the upper mold until the pressure value reaches the predetermined target pressure. During this process, excess gas and slurry in the mold cavity and concrete matrix are forcibly discharged through the slurry discharge and exhaust channel and / or slurry discharge channel. While maintaining the pressure of the press, tighten the second fastening component to lock the upper mold and the lower mold into a whole; Remove the mold, allowing the concrete inside the mold cavity to continue to be compressed under the constraint of the mold; After curing for the specified time, the formwork is removed and the axially tensile concrete specimen is obtained.

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