A pre-set continuous fiber ultra-high performance cement-based material and its preparation method

Abstract

The present invention provides a preparation method of a pre-set continuous fiber ultra-high performance cement-based material, comprising the following steps: S1, making a mold according to a cement product, winding steel fibers on a wire drum, and then sequentially passing the starting end of the fibers through a left perforated plate and a right perforated plate, fixing the left perforated plate, and moving the right perforated plate to the right end of the mold and fixing it; S2, using a right-bent pressing plate to bend the end of the steel fibers on the outside of the right perforated plate to fix them, tightening the steel fibers, and then using a left-bent pressing plate to bend the end of the steel fibers on the outside of the left perforated plate to fix them, loosening the wire drum, and cutting the steel fibers fixed by the left perforated plate to obtain a preset steel wire array; S3, pouring a high-strength cement matrix into the mold and curing it, thereby obtaining a pre-set continuous fiber ultra-high performance cement-based material. The method of pre-setting steel fibers provided by the present invention can ensure that the steel fibers are accurately positioned, the steel fibers are subjected to synchronous and uniform force, and the quality of the cement-based composite material is guaranteed and the performance is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cement materials, and in particular to a pre-set continuous fiber ultra-high performance cement-based material and a preparation method thereof. Background Art

[0002] Brittleness and low tensile strength are hallmarks of cement-based materials, a major factor preventing their application in many applications. Numerous methods have been employed to improve the tensile strength of cement-based materials, including fiber reinforcement, which is an effective approach. Among these fiber reinforcement methods, steel fibers offer the most impressive results. However, steel fiber reinforcement of cement-based materials can be achieved using both short fibers and long fiber grids, each with its own advantages and disadvantages. However, the results achieved by these reinforcement methods are often less than satisfactory.

[0003] When short-cut steel fibers are used to reinforce cement-based materials, the fiber orientation is random, and the fiber reinforcement efficiency is not high, generally less than 50%. In addition, short fibers are easily pulled out during the tensile process, so the tensile potential of the steel fibers is not fully utilized. When long fibers or fiber grids are used for reinforcement, the long fibers or grids are often not tensioned and are in a bent state in the cement matrix. The stress level of each tensile fiber is different (the force between individual fibers is not synchronized), and the tensile strength and other mechanical properties of the cement-based material cannot be effectively improved.

[0004] Because the steel fibers in traditional steel fiber reinforced cement-based materials are subjected to uneven stress, their mechanical properties such as tensile strength are poor. When used in the main structure of the cages in marine ranches, their stability against wind and waves decreases, and the exposed steel fibers cause surface corrosion, affecting the durability of the material and structure. In addition, the above problems also exist when they are used in marine projects such as marine floating platforms, marine buoys, wind turbine towers, and wind turbine floating bases. Summary of the Invention

[0005] In view of this, the present invention proposes a pre-set continuous fiber ultra-high performance cement-based material and a preparation method thereof.

[0006] The technical solution of the present invention is achieved as follows:

[0007] A method for preparing a pre-set continuous fiber ultra-high performance cement-based material comprises the following steps:

[0008] S1. A mold for cement products is prepared. A rotatable steel wire drum is fixed to the outside of the left end of the mold. Steel fiber is wound around the steel wire drum. The starting end of the steel fiber is then passed through the left and right perforated plates at the left end of the mold in sequence. The left perforated plate is secured by the left plate slot. The right perforated plate is then moved to the right end of the mold through a slide on the mold and secured by the right plate slot.

[0009] S2. Use the right-bending pressure plate to bend and fix the ends of the steel fibers on the outside of the right perforated plate. Control the wire drum to tighten the steel fibers. Then use the left-bending pressure plate to bend and fix the ends of the steel fibers on the outside of the left perforated plate. Release the wire drum and cut the steel fibers fixed to the left perforated plate to obtain a preset steel wire array.

[0010] S3. After pouring a high-strength cement matrix into a mold containing a preset steel wire array and solidifying it, a preset continuous fiber ultra-high performance cement-based material is obtained.

[0011] Furthermore, the high-strength cement matrix is ​​ultra-high performance concrete.

[0012] Furthermore, the device for preparing pre-set continuous fiber ultra-high performance cement-based material includes a mold, a symmetrically arranged left perforated plate and right perforated plate that can allow steel fibers to pass through, a left bending pressure plate, and a right bending pressure plate; the left perforated plate matches the size of the left end of the mold and is movably connected to the left end of the mold, and the right perforated plate matches the size of the right end of the mold and is movably connected to the right end of the mold; a left insert plate groove is provided on the upper part of the left end of the mold, and a right insert plate groove is provided on the upper part of the right end of the mold; the top of the left perforated plate matches the size of the left insert plate groove and is fixed by the left insert plate groove, and the top of the right perforated plate matches the size of the right insert plate groove and is fixed by the right insert plate groove; a slide matching the size of the left and right perforated plates is provided on the mold; a steel wire drum rotatable around an axis is fixed to the outer side of the left end of the mold; the left bending pressure plate and the right bending pressure plate are respectively located at the left and right ends of the mold to bend and fix the steel fibers that pass through.

[0013] Furthermore, the left perforated plate and the right perforated plate are a whole plate or are formed by stacking a plurality of narrow perforated plates.

[0014] Furthermore, the left perforated plate and the right perforated plate are respectively distributed with a plurality of perforations, and the perforations of the left perforated plate and the perforations of the right perforated plate are symmetrical with respect to a vertical plane.

[0015] Furthermore, the left bending pressure plate and the right bending pressure plate are connected by a strong spring.

[0016] Furthermore, the pressure heads at the lower front ends of the left-bending pressure plate and the right-bending pressure plate are arc-shaped pressure heads.

[0017] The pre-set continuous fiber ultra-high performance cement-based material is prepared by the preparation method of the present invention.

[0018] Furthermore, the left perforated plate and the right perforated plate of the present invention may also be standardized and universal. In this case, not all holes have steel wires passing through them. According to the design, some holes are idle and can be reused.

[0019] Furthermore, the left perforated plate of the present invention can be used as the left end template of the mold, and the right perforated plate can be used as the right end template of the mold.

[0020] Furthermore, when producing high tensile strength cement products, the longitudinal direction of the steel fibers is consistent with the direction of tensile stress, and the steel fibers are arranged into a multi-layer, multi-column, parallel and evenly distributed longitudinal array; when producing high flexural strength cement products, the direction of the steel fiber arrangement is the same as the length direction of the specimen, and the fiber density is sparse at the top and dense at the bottom.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The method for pre-setting steel fibers provided by the present invention can ensure that the steel fibers are accurately positioned and the steel fibers are subjected to force synchronously and evenly, thereby ensuring the quality of the cement-based composite material and effectively improving its performance.

[0023] (2) The fiber-reinforced cement products prepared by the present invention can have a tensile strength that is more than 0.5 times higher than that of conventional UHPC (ultra-high performance concrete) products and their flexural strength is also increased, while the cost remains basically unchanged or can even be slightly reduced.

[0024] (3) According to the steel fiber reinforced cement-based material prepared by the present invention, the steel fibers are evenly distributed in the high-strength cement matrix, which can provide good protection for the steel fibers (steel wires) and improve their durability, especially the structural durability in marine environments.

[0025] (4) Since the orientation degree of the reinforcing fibers is greatly improved, even close to the ideal degree, the fiber reinforcement efficiency is greatly improved, creating conditions for significantly improving the physical and mechanical properties of fiber-reinforced composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 This is a structural schematic diagram of the steel fiber stretching process of the present invention.

[0028] Figure 2 This is a front cross-sectional view of the steel fiber after being stretched and fixed by the right perforated plate of the present invention.

[0029] Figure 3 This is a schematic diagram of the structure of the right-bent pressing plate of the present invention pressing down and fixing the steel fiber.

[0030] Figure 4 This is a schematic diagram of the front view structure of the right perforated plate of the present invention.

[0031] Figure 5 It is a right side view of the mold after the steel fiber of the present invention is fixed.

[0032] Figure 6 Schematic diagram of the structure of the slit plate of the present invention.

[0033] Figure 7 This is a front cross-sectional view of the mold after the steel fiber is stretched.

[0034] Figure 8 This is a top sectional view of the mold after the steel fiber is stretched.

[0035] Figure 9 The figure is a top sectional view of a mold in which vertical steel fibers are added after the steel fibers are stretched according to the present invention.

[0036] In the figure, 1-mold, 2-left perforated plate, 3-right perforated plate, 31-perforation, 4-steel fiber, 5-wire roller, 6-right insert plate slot, 7-right bending pressure plate, 8-slit plate. DETAILED DESCRIPTION

[0037] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0039] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0040] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0041] The manufacturer of the UHPC ultra-high performance concrete of the present invention is Shandong Bohao Building Materials Co., Ltd., and the product name is UHPC ultra-high performance concrete.

[0042] The device for preparing pre-set continuous fiber ultra-high performance cement-based material of the present invention comprises a mold 1, a symmetrically arranged left perforated plate 2 and a right perforated plate 3 capable of allowing steel fibers 4 to pass through, a left bent pressing plate, and a right bent pressing plate 7; the left perforated plate 2 matches the size of the left end of the mold 1 and is movably connected to the left end of the mold 1, and the right perforated plate 3 matches the size of the right end of the mold 1 and is movably connected to the right end of the mold 1; a left inserting plate groove is provided on the upper part of the left end of the mold 1, and a right inserting plate groove 6 is provided on the upper part of the right end of the mold 1; the left perforated plate 2 and the right perforated plate 3 respectively match the sizes of the left end and the right end of the mold 1 and are movably connected to the left end and the right end of the mold 1, and the left inserting plate groove and the right inserting plate groove 6 are respectively provided on the upper part of the left end and the right end of the mold 1. The top of the left perforated plate 2 matches the size of the left inserting plate slot and is fixed by the left inserting plate slot, and the top of the right perforated plate 3 matches the size of the right inserting plate slot 6 and is fixed by the right inserting plate slot 6; the mold 1 is provided with a slideway that matches the size of the left perforated plate 2 and the right perforated plate 3; a steel wire drum 5 that can rotate around an axis is fixed to the outer side of the left end of the mold 1; the left bending pressure plate and the right bending pressure plate 7 are respectively located at the left and right ends of the mold 1, and the steel fiber 4 passing through is bent and fixed; the left bending pressure plate and the right bending pressure plate 7 are connected by a strong spring; a number of perforations 31 are evenly distributed on each of them, and the perforations of the left perforated plate and the perforations of the right perforated plate 3 are symmetrical with respect to the vertical plane; the lower front end pressure heads of the left bending pressure plate and the right bending pressure plate 7 are arc-shaped pressure heads.

[0043] According to the principles of composite material construction, the tensile strength of a composite material is the contribution of the tensile strengths of the fibers and matrix, respectively. Ignoring the tensile strength of the cement matrix, the tensile strength (A1) of the composite material is simply the tensile strength of the steel fibers (A2) multiplied by the volume percentage of the steel fiber content (V%): A1 / A2 = V% (this is the volume percentage of the fiber in the tensile axis). This is used as a benchmark in the present invention to prepare ultra-high-performance cement-based materials pre-loaded with continuous fibers.

[0044] Example 1

[0045] like Figure 1-5 As shown, the preparation method of the pre-set continuous fiber ultra-high performance cement-based material with a tensile strength of 25 MPa comprises the following steps:

[0046] S1. A mold 1 is made according to cement products. The left and right perforated plates 2 and 3 have matching sizes and are provided with a number of perforations 31 evenly distributed in the horizontal and vertical directions. The left and right perforated plates 2 and 3 are both placed at the left end of the mold 1. A steel wire drum 5 rotatable around an axis is fixed on the outside of the left end of the mold 1. Steel fibers with a tensile strength grade of 1000 MPa are taken and wound around the steel wire drum. The starting ends of the steel fibers 4 are then passed through the left and right perforated plates 2 and 3 in sequence. After the left perforated plate 2 is fixed through the left inserting plate slot, the right perforated plate 3 is moved to the right end of the mold 1 through the slide on the mold 1. At this time, multiple steel fibers 4 are pulled to the right end of the mold 1. When the right perforated plate 3 reaches the right end of the mold 1, it is pressed into the right inserting plate slot 6 at the right end for fixation.

[0047] S2, the left bending pressure plate and the right bending pressure plate 7 are connected by a strong spring, and the lower ends of the left bending pressure plate and the right bending pressure plate 7 are arc-shaped pressure heads; the right bending pressure plate 7 is moved from top to bottom close to the outer side of the right perforated plate 3, and the right bending pressure plate 7 is bent and clamped one by one during the movement from top to bottom; the wire drum 5 is controlled to tighten the steel fiber 4, and then the left bending pressure plate is used to bend the end of the steel fiber 4 on the outer side of the left perforated plate 2, and the left bending pressure plate and the right bending pressure plate 7 are clamped between the left perforated plate 2 and the right perforated plate 3 by the action of the strong spring; the wire drum 5 is relaxed, and the steel fiber 4 connected to the wire drum 5 is cut off to obtain a preset steel wire array;

[0048] S3. According to the steel wire array content accounting for 2.50% of the total volume of the high-strength cement matrix, the high-strength cement matrix is ​​poured into the mold 1 containing the preset steel wire array and solidified to obtain the preset continuous fiber ultra-high performance cement-based material.

[0049] According to Example 1, a rectangular pre-set continuous fiber ultra-high performance cement-based product was prepared, and then compared with a conventional ultra-high performance concrete product of the same specifications prepared by mixing ultra-high performance concrete with chopped steel fibers in the same volume. In Example 1 of the present invention, since the steel fibers are uniformly stretched during the arrangement process and are arranged in parallel along the direction of the principal stress in three-dimensional space, the reinforcement efficiency of the steel fibers can be greatly improved, and the tensile strength of the steel fibers is 1.6 times that of the conventional ultra-high performance concrete.

[0050] Example 2

[0051] like Figure 1-5 As shown, the preparation method of the pre-set continuous fiber ultra-high performance cement-based material with a tensile strength of 25 MPa comprises the following steps:

[0052] S1. A mold 1 is made according to cement products. The left and right perforated plates 2 and 3 have matching sizes and are provided with a number of perforations 31 evenly distributed in the horizontal and vertical directions. The left and right perforated plates 2 and 3 are both placed on the left end of the mold 1. A steel wire drum 5 rotatable around an axis is fixed on the outside of the left end of the mold 1. Steel fibers with a tensile strength grade of 600 MPa are taken and wound around the steel wire drum. The starting ends of the steel fibers 4 are then passed through the left and right perforated plates 2 and 3 in sequence. After the left perforated plate 2 is fixed through the left inserting plate slot, the right perforated plate 3 is moved to the right end of the mold 1 through the slide on the mold 1. At this time, multiple steel fibers 4 are pulled to the right end of the mold 1. When the right perforated plate 3 reaches the right end of the mold 1, it is pressed into the right inserting plate slot 6 at the right end for fixation.

[0053] S2, the left bending pressure plate and the right bending pressure plate 7 are connected by a strong spring, and the lower ends of the left bending pressure plate and the right bending pressure plate 7 are arc-shaped pressure heads; the right bending pressure plate 7 is moved from top to bottom close to the outer side of the right perforated plate 3, and the right bending pressure plate 7 is bent and clamped one by one during the movement from top to bottom; the wire drum 5 is controlled to tighten the steel fiber 4, and then the left bending pressure plate is used to bend the end of the steel fiber 4 on the outer side of the left perforated plate 2, and the left bending pressure plate and the right bending pressure plate 7 are clamped between the left perforated plate 2 and the right perforated plate 3 by the action of the strong spring; the wire drum 5 is relaxed, and the steel fiber 4 connected to the wire drum 5 is cut off to obtain a preset steel wire array;

[0054] S3. According to the steel wire array content of 4.17% of the total volume of the high-strength cement matrix, the high-strength cement matrix is ​​poured into the mold 1 containing the preset steel wire array and solidified to obtain the preset continuous fiber ultra-high performance cement-based material.

[0055] According to Example 2, a rectangular pre-set continuous fiber ultra-high performance cement-based product was prepared, and then compared with a conventional ultra-high performance concrete product of the same specifications prepared by mixing ultra-high performance concrete with short-cut steel fibers and the same volume. In Example 2 of the present invention, since the steel fibers are uniformly stretched during the arrangement process and are arranged in parallel along the direction of the principal stress in three-dimensional space, the reinforcement efficiency of the steel fibers can be greatly improved, so that the tensile strength can also reach 1.6 times the tensile strength of the conventional ultra-high performance concrete product.

[0056] In addition, the steel fiber reinforced cement-based material prepared according to the present invention can improve the durability of the steel fiber (steel wire), especially the structural durability in the marine environment, because it plays a good protective role on the steel fiber (steel wire).

[0057] like Figure 6 As shown, the method of the present invention can also be used to arrange grid-like continuous steel fibers. During the arrangement, a slit plate 8 is used to clamp the grid-like continuous steel fibers and fix them.

[0058] like Figure 7 and Figure 8 As shown, when making high tensile strength cement products, the longitudinal direction of the steel fibers 4 is consistent with the direction of tensile stress, and the steel fibers 4 are arranged into a multi-layer, multi-row, mutually parallel and evenly distributed longitudinal array (such as Figure 7 As shown in the front view of the mold, the steel fibers 4 are arranged in layers when viewed from the side. Figure 8 When viewed from the front view of the mold, that is, from top to bottom, the steel fibers 4 are arranged in rows. When producing high-flexural-strength cement products, the direction of the steel fibers 4 is the same as the length direction of the specimen, and the density of the steel fibers 4 is sparse at the top and dense at the bottom.

[0059] like Figure 9 As shown, in order to further improve the reinforcement effect, several connecting steel fibers 4 can be added on the same plane perpendicular to the direction of the steel fibers 4 to increase their stress.

[0060] In addition, when irregular cement products need to be made, they are divided into several regular small blocks and then assembled.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a pre-set continuous fiber ultra-high performance cement-based material, characterized in that: The following steps are involved: S1. A mold for cement products is prepared. A rotatable steel wire drum is fixed to the outside of the left end of the mold. Steel fiber is wound around the steel wire drum. The starting end of the steel fiber is then passed through the left and right perforated plates at the left end of the mold in sequence. The left perforated plate is secured by the left plate slot. The right perforated plate is then moved to the right end of the mold through a slide on the mold and secured by the right plate slot. S2. Use the right-bending pressure plate to bend and fix the ends of the steel fibers on the outside of the right perforated plate. Control the wire drum to tighten the steel fibers. Then use the left-bending pressure plate to bend and fix the ends of the steel fibers on the outside of the left perforated plate. Release the wire drum and cut the steel fibers fixed to the left perforated plate to obtain a preset steel wire array. S3. After pouring a high-strength cement matrix into a mold containing a preset steel wire array and solidifying it, a preset continuous fiber ultra-high performance cement-based material is obtained.

2. The method for preparing the pre-set continuous fiber ultra-high performance cement-based material according to claim 1, characterized in that: The high-strength cement matrix is ​​ultra-high performance concrete.

3. The method for preparing the pre-set continuous fiber ultra-high performance cement-based material according to claim 1, characterized in that: The device for preparing pre-set continuous fiber ultra-high performance cement-based material includes a mold, a symmetrically arranged left perforated plate and a right perforated plate that can allow steel fibers to pass through, a left bent pressure plate, and a right bent pressure plate; the left perforated plate matches the size of the left end of the mold and is movably connected to the left end of the mold, and the right perforated plate matches the size of the right end of the mold and is movably connected to the right end of the mold; a left inserting plate groove is provided on the upper part of the left end of the mold, and a right inserting plate groove is provided on the upper part of the right end of the mold; the top of the left perforated plate matches the size of the left inserting plate groove and is fixed by the left inserting plate groove, and the top of the right perforated plate matches the size of the right inserting plate groove and is fixed by the right inserting plate groove; a slideway matching the size of the left perforated plate and the right perforated plate is provided on the mold; a steel wire drum rotatable around an axis is fixed on the outer side of the left end of the mold; the left bent pressure plate and the right bent pressure plate are respectively located at the left and right ends of the mold to bend and fix the steel fibers that pass through.

4. The method for preparing the pre-placed continuous fiber ultra-high performance cement-based material according to claim 3, characterized in that: The left perforated plate and the right perforated plate are an integral plate or are formed by stacking a plurality of narrow perforated plates.

5. The method for preparing the pre-placed continuous fiber ultra-high performance cement-based material according to claim 3, characterized in that: The left perforated plate and the right perforated plate are respectively distributed with a plurality of perforations, and the perforations of the left perforated plate and the perforations of the right perforated plate are symmetrical with respect to a vertical plane.

6. The method for preparing the pre-set continuous fiber ultra-high performance cement-based material according to claim 3, characterized in that: The left bending pressure plate and the right bending pressure plate are connected via a strong spring.

7. The method for preparing the pre-placed continuous fiber ultra-high performance cement-based material according to claim 3, characterized in that: The pressure heads at the lower front ends of the left-bending pressure plate and the right-bending pressure plate are arc-shaped pressure heads.

8. Pre-set continuous fiber ultra-high performance cement-based material prepared by the preparation method according to any one of claims 1 to 7.

Images