High-ductility cement-based material four-point bending test workpiece mold and use method
By designing a vertical four-point bending test mold and a partitioned module venting structure, the problems of difficult demolding and poor venting of high-ductility cement-based materials were solved, achieving efficient specimen molding and testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-31
AI Technical Summary
In the existing technology, it is difficult to demold the mold for the four-point bending test of high ductility cement-based materials, and poor air venting leads to bulging and peeling of the specimen surface.
A vertical four-point bending test mold is designed, which adopts a partitioned module and vent structure, combined with the casting and demolding process, to reduce the contact area with the base plate and expel air from the material.
This method enables smooth demolding of high-ductility cement-based materials, reduces specimen damage, and improves the success rate and data accuracy of the test.
Smart Images
Figure CN121756447A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mechanical property testing of high-ductility cement-based materials, specifically to a mold for preparing a four-point bending test specimen of high-ductility cement-based materials and its usage method. Background Technology
[0002] High-ductility cementitious materials are fiber-reinforced cementitious materials with extremely high ductility and multi-crack resistance. They are generally composed of controlled quantities of cement, fly ash, refined silica sand, PVA fibers, and high-efficiency water-reducing agents. By adjusting the properties of the matrix and the fiber / matrix interface, high-ductility cementitious materials with excellent strain-hardening properties can be obtained.
[0003] The flexural toughness of high-ductility cementitious materials is generally analyzed by testing four-point bending performance. Thin-plate specimens are commonly used in this test. Currently, there are no corresponding standards for the four-point bending test of high-ductility cementitious materials, and standard molds for preparing thin-plate four-point bending test specimens are not available on the market. Therefore, self-made molds are typically used to form thin-plate specimens of high-ductility cementitious materials.
[0004] Generally, the molds for four-point bending tests of self-made high-ductility cement-based materials are mostly of a flat design, meaning that the longitudinal and transverse sides in contact with the base plate are relatively long, while the thickness of the specimen perpendicular to the mold is relatively thin. This causes a problem: it is difficult to demold the high-ductility cement-based material after casting. This is because high-ductility cement-based materials use a large amount of fly ash, do not use coarse aggregate, and incorporate about 1.5%-2.0% fiber, resulting in the high-ductility cement-based material adhering too tightly to the mold after initial setting, easily causing damage to the thin-plate specimen during demolding. Summary of the Invention
[0005] This invention proposes a mold for a four-point bending test specimen of high-ductility cement-based materials, which can solve the problems of bulging and peeling on the surface of specimens caused by difficulty in demolding and poor air venting of high-ductility cement-based materials. The second objective of this invention is to provide a method for manufacturing test pieces based on the aforementioned mold, as well as a testing method.
[0006] The specific solution of this invention is as follows: a mold for preparing a four-point bending test specimen of a high-ductility cement-based material is proposed, comprising: A base plate, on which end plates and partitions are provided, the end plates are provided at both ends, and multiple partitions are spaced apart, with both ends respectively abutting against the end plates to form multiple thin plate-shaped specimen areas of the same shape and a middle partition area; The partition is assembled from a perforated plate and a baffle plate. The perforated plate is provided with an installation groove that matches the size of the baffle plate, and multiple sets of vent holes are provided on the surface of the installation groove plate.
[0007] Furthermore, the base plate is provided with a transverse groove and a longitudinal groove, the width of the transverse groove is the same as the thickness of the end plate, and the thickness of the longitudinal groove is the same as the thickness of the partition plate.
[0008] Furthermore, the base plate is fixedly connected to a fixing plate on the outside of the transverse groove. The fixing plate is arranged parallel to the transverse groove, and a screw is threadedly connected to the fixing plate.
[0009] Furthermore, a handle is fixed to the end of the screw away from the transverse groove.
[0010] Furthermore, the end plate and the partition are at the same height, and the end plate is provided with a vertically arranged groove. The width of the groove is the same as the thickness of the partition, and the groove depth is 1-2 mm.
[0011] Furthermore, the mounting groove has triangular cross-section guide grooves on both sides along the vertical direction, and guide bosses matching the guide grooves are fixed on both sides of the baffle.
[0012] Furthermore, the height of the baffle plate is the same as the depth of the mounting groove.
[0013] Furthermore, the diameter of the exhaust port is 0.1-0.3 mm, and the spacing is 5-10 mm.
[0014] A method for preparing a four-point bending test specimen of a high-ductility cement-based material includes a casting process and a demolding process to obtain a thin plate specimen for the four-point bending test of the high-ductility cement-based material. The casting process includes the following steps: Step 1, Assemble the test mold assembly: Insert the end plate and the perforated plate into the corresponding horizontal and vertical grooves on the bottom plate, respectively. The side of the perforated plate with the mounting groove facing the outside of the thin plate-shaped test piece area. Turn the handle to tighten the screw against the end plate, so that the end plate and the perforated plate are firmly installed. Then apply grease to the inner surface of the assembled mold. Step 2, pouring high-ductility cement-based material: pour the freshly mixed high-ductility cement-based material into the thin plate-shaped specimen area in three layers. After each layer is poured, place the specimen mold along with the poured high-ductility cement-based material on a vibrating table and vibrate for 120 seconds. Step 3, install the partition plate: insert the partition plate into the installation groove, wipe off the high-ductility cement-based material that overflows from the outside of the perforated plate with a damp towel, smooth the high-ductility cement-based material along the upper edge of the end plate with a trowel, cover it with plastic film, and place it in a standard curing room for 24 hours.
[0015] The demolding and experimental procedures include the following steps: S1, rotate the handle to move the screw away from the end plate, tap the bottom plate to separate the bottom plate from the end plate and the partition plate, tap the end plate again to separate the end plate from the partition plate, and tap each partition plate to separate them to obtain a four-point bending thin plate specimen of high ductility cement-based material. S2. Place the high-ductility cement-based material four-point bending thin plate specimen in a standard curing room and cure it to the specified age. Then, place the high-ductility cement-based material four-point bending thin plate specimen on a support and conduct a four-point bending test using an electro-hydraulic servo universal testing machine.
[0016] The present invention has the following advantages: (1) Change the molding method of the four-point thin plate bending specimen of high ductility cement-based material from flat to vertical to reduce the contact area between the high ductility cement-based material and the base plate, reduce the demolding difficulty, and at the same time reduce the area of the smoothing surface, so that the test surface of the test specimen is smoother. (2) The partition module of the specimen molding template consists of two parts. The vent holes reserved on the perforated plate can discharge the air remaining in the high ductility cement-based material during the layered pouring and vibration process, thereby reducing the hollow and peeling damage on the surface of the specimen. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the base plate of a mold for a four-point bending part made of high-ductility cement-based material; Figure 2 This is a schematic diagram of the end plate of a mold for a four-point bending part made of high-ductility cement-based material; Figure 3 This is a schematic diagram of a mold partition for a four-point bending part made of high-ductility cement-based material; Figure 4 for Figure 3 Another structural diagram; Figure 5 This is a schematic diagram of the assembly of a mold for a four-point bending component made of high-ductility cement-based material; Figure 6 This is a schematic diagram of the test process for the specimen of the present invention. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0019] like Figures 1-6 As shown, a mold for preparing a four-point bending test specimen of a high-ductility cement-based material includes, The base plate 10 is provided with an end plate 101 and a partition plate 102. The end plate 101 is provided at both ends, and multiple partition plates 102 are spaced apart and the two ends are respectively pressed against the end plate 101 to form multiple thin plate-shaped specimen areas 103 and a middle partition area 104. The partition 102 is assembled from a perforated plate 1021 and a baffle 1022. The perforated plate 1021 is provided with a mounting groove 1023 that matches the size of the baffle 1022. Multiple sets of vent holes 1024 are provided on the surface of the mounting groove 1023.
[0020] Furthermore, the base plate 10 is provided with a transverse groove 105 and a longitudinal groove 106. The width of the transverse groove 105 is the same as the thickness of the end plate 101, and the thickness of the longitudinal groove 106 is the same as the thickness of the partition plate 102. The groove depth is 1-2 mm.
[0021] Furthermore, the base plate 10 is fixedly connected to a fixing plate 107 on the outside of the transverse groove 105. The fixing plate 107 is arranged parallel to the transverse groove 105, and a screw 1071 is threadedly connected to the fixing plate 107.
[0022] Furthermore, a handle 1072 is fixed to the end of the screw 1071 away from the transverse groove 105.
[0023] Furthermore, the end plate 101 and the partition plate 102 are at the same height, and the end plate 101 is provided with a vertically arranged groove 1011. The width of the groove 1011 is the same as the thickness of the partition plate 102, and the groove 1011 is 1-2 mm deep.
[0024] Furthermore, the mounting groove 1023 has triangular cross-section guide grooves 10231 on both sides along the vertical direction, and the baffle plate 1022 has guide bosses 10221 that match the guide grooves 10231 fixed on both sides.
[0025] Furthermore, the height of the baffle plate 1022 is the same as the depth of the mounting groove 1023.
[0026] Furthermore, the vent hole 1024 has a diameter of 0.1-0.3 mm and a spacing of 5-10 mm.
[0027] A method for using a mold for a four-point bending test specimen of a high-ductility cement-based material includes a casting process and a demolding process to obtain a thin plate specimen 18 for a four-point bending test of a high-ductility cement-based material. The casting process includes the following steps: Step 1, Assemble the test mold assembly: Insert the end plate 101 and the perforated plate 1021 into the corresponding transverse grooves 105 and longitudinal grooves 106 on the bottom plate 10, respectively. The side of the perforated plate 1021 with the mounting groove 1023 faces the outside of the thin plate-shaped test piece area 15. Turn the handle 1072 so that the screw 1071 presses against the end plate 101, so that the end plate 101 and the perforated plate 1021 are firmly installed. Then apply grease to the inner surface of the assembled mold. Step 2, pouring high-ductility cement-based material: pour the freshly mixed high-ductility cement-based material into the thin plate-shaped specimen area 15 in three layers. After each layer is poured, place the specimen mold along with the poured high-ductility cement-based material on a vibrating table and vibrate for 120 seconds. Step 3, install the partition plate 1022: insert the partition plate 1022 into the installation groove 1023, wipe off the high ductility cement-based material overflowing from the outside of the perforated plate 1021 with a damp towel, smooth the high ductility cement-based material along the upper edge of the end plate 101 with a trowel, cover it with plastic film, and place it in a standard curing room for 24 hours.
[0028] The demolding and experimental procedures include the following steps: S1, rotate handle 1072 to move screw 1071 away from end plate 101, tap bottom plate 10 lightly to separate bottom plate 10 from end plate 101 and partition 102, tap end plate 101 lightly to separate end plate 101 from partition 102, tap each partition 102 lightly to separate them, and obtain a high ductility cement-based material four-point bending thin plate specimen; S2, place the high-ductility cement-based material four-point bending thin plate specimen in a standard curing room and cure it to the specified age. Place the high-ductility cement-based material four-point bending thin plate specimen on support 17 and carry out the four-point bending test using an electro-hydraulic servo universal testing machine.
[0029] This mold can be designed with suitable specimen dimensions according to actual needs, such as... Figure 6 As shown, the specimen prepared in this embodiment has dimensions of 400 mm × 70 mm × 16 mm. The specimen prepared by the above method was tested, as follows... Figure 6 As shown, the thin plate specimen 18 is placed on the support 17, and the electro-hydraulic servo universal testing machine is used to start loading using the displacement loading method until the thin plate specimen 18 breaks or loses its load-bearing capacity, thus completing the test.
[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A mold for a four-point bend test specimen of a high ductility cementitious material, characterized by: The utility model relates to a four-point bending test piece mold for high ductility cement-based material, including casting process and demolding process, and the four-point bending test piece (18) of high ductility cement-based material is prepared. The utility model discloses a four-point bending test piece mold for high ductility cement-based material, which comprises a bottom plate (10) provided with end plates (101) and partition plates (102). The partition plate (102) is assembled by a hole-keeping plate (1021) and a partition plate (1022), the hole-keeping plate (1021) is provided with mounting grooves (1023) matched with the partition plate (1022) in size, and a plurality of groups of exhaust holes (1024) are arranged on the surface of the mounting grooves (1023).
2. A mold for a high ductility cementitious material four-point bend test specimen according to claim 1, characterized in that: The bottom plate (10) is provided with transverse grooves (105) and longitudinal grooves (106), the width of the transverse grooves (105) is the same as the thickness of the end plates (101), and the thickness of the longitudinal grooves (106) is the same as the thickness of the partition plates (102).
3. A mold for a high ductility cementitious material four-point bend test specimen according to claim 2, wherein: The bottom plate (10) is provided with transverse grooves (105) and longitudinal grooves (106), the width of the transverse grooves (105) is the same as the thickness of the end plates (101), and the thickness of the longitudinal grooves (106) is the same as the thickness of the partition plates (102).
4. A mold for four-point bending test specimens of a high ductility cementitious material according to claim 3, characterized in that: The bottom plate (10) is provided with transverse grooves (105) and longitudinal grooves (106), the width of the transverse grooves (105) is the same as the thickness of the end plates (101), and the thickness of the longitudinal grooves (106) is the same as the thickness of the partition plates (102).
5. A mold for a high ductility cementitious material four-point bend test specimen according to claim 3, characterized in that: The end plates (101) and the partition plates (102) are of the same height, the end plates (101) are provided with vertical grooves (1011), the width of the grooves (1011) is the same as the thickness of the partition plates (102), and the groove depth of the grooves (1011) is 1-2 mm.
6. A mold for a high ductility cementitious material four-point bend test specimen according to claim 1, wherein: The two sides of the mounting grooves (1023) are provided with guide grooves (10231) in a triangular cross section along the vertical direction, and the two sides of the partition plate (1022) are fixedly provided with guide bosses (10221) matched with the guide grooves (10231).
7. A mold for four-point bending test specimens of a high ductility cementitious material according to claim 6, characterized in that: The height of the partition plate (1022) is the same as the depth of the mounting grooves (1023).
8. A mold for a high ductility cementitious material four-point bend test specimen according to claim 1, characterized in that: The diameter of the exhaust holes (1024) is 0.1-0.3 mm, and the spacing is 5-10 mm.
9. A method for fabricating and testing a four-point bending test specimen of a high-ductility cement-based material, characterized in that: The four-point bending test piece mold for high ductility cement-based material is used to prepare a four-point bending test thin plate test piece (18) of high ductility cement-based material through a casting process and a demolding process. The casting process comprises the following steps: Step one, assembling the test mold assembly: the end plates (101) and the hole-keeping plates (1021) are respectively inserted into the corresponding transverse grooves (105) and longitudinal grooves (106) on the bottom plate (10), wherein the side of the hole-keeping plate (1021) provided with the mounting grooves (1023) faces the outside of the thin plate-shaped test piece area (103), the handle (1072) is rotated, the screw rod (1071) tightly abuts against the end plate (101), the end plate (101) and the hole-keeping plate (1021) are firmly installed, and then butter is applied to the inner surface of the assembled mold. Step two, pouring high ductile cement-based material: the fresh high ductile cement-based material is poured into the thin plate-shaped test specimen area (103) in three layers, after each layer is poured, the test mold is placed on the vibration table together with the poured high ductile cement-based material and vibrated for 120s; Step three, installing grid baffle (1022): inserting the baffle (1022) into the installation groove (1023), wiping off the high ductile cement-based material overflowing outside the hole plate (1021) with a wet towel, using a spatula to smooth the high ductile cement-based material along the end plate (101), covering plastic film, and placing in a standard curing room for curing for one day and night; The demolding process and experimental process include the following steps: S1, rotating the handle (1072) to make the screw rod (1071) away from the end plate (101), tapping the bottom plate (10) to separate the bottom plate (10) from the end plate (101) and the baffle (102), then tapping the end plate (101) to separate the end plate (101) from the baffle (102), and then tapping each baffle (102) to obtain a high ductile cement-based material four-point bending thin plate test specimen; S2, placing the high ductile cement-based material four-point bending thin plate test specimen in a standard curing room for curing to the specified age, placing the high ductile cement-based material four-point bending thin plate test specimen on the support (17), and using an electro-hydraulic servo universal testing machine to carry out four-point bending test.