A method and device for preparing high performance concrete

Abstract

This invention discloses a method and apparatus for preparing high-performance concrete. The method involves pre-mixing fine aggregate and fiber in the apparatus for 30 seconds; then sequentially adding coarse aggregate, expansion agent, cement, fly ash, water, and admixtures, followed by wet mixing for 90 seconds to obtain high-performance concrete. This invention provides a method for preparing high-performance concrete that, through the selection of raw materials and the determination of the mixing method, provides concrete with "high ductility, high toughness, low shrinkage, and low modulus of elasticity." Simultaneously, it provides a concrete preparation apparatus that solves the dust problem during fiber addition. Furthermore, the fiber is mixed with fine aggregate through a linear, intermittent addition method, improving the uniformity of the mixture and preventing fiber clumping after mixing, thus significantly improving the mixing quality and performance of the concrete.

Description

Technical Field

[0001] This invention relates to the field of concrete preparation technology, and in particular to a method and apparatus for preparing high-performance concrete. Background Technology

[0002] Concrete panels are widely used in water conservancy and hydropower projects, serving to protect the main structure of the project and resist water seepage, and have an important impact on the safety and durability of the project structure.

[0003] Due to the large-area construction of concrete panels within a short period, the cumulative shrinkage deformation during the concrete setting and hardening process can generate significant tensile stress along its length. When the length of the subsequently poured concrete panel is large (exceeding 100 meters) and simultaneously subjected to the restraining force of the pre-poured concrete, the resulting tensile stress often exceeds the tensile strength of the concrete itself, leading to cracking and failure. Therefore, to avoid this failure, engineers need to develop a high-performance concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" to prevent cracking.

[0004] However, concrete is a brittle material with cement as the binder. It has high compressive strength but low tensile strength (approximately 1 / 10 of its compressive strength), contains numerous microcracks and pores, and undergoes setting shrinkage, drying shrinkage, and temperature shrinkage during hardening. Ordinary concrete often exhibits characteristics of "high brittleness, low toughness, high shrinkage, and medium-high elastic modulus." Therefore, developing a high-performance concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" to prevent cracking and damage is crucial. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a method and apparatus for preparing high-performance concrete. Based on the types of raw materials selected and the mixing method, it solves the defects of existing concrete, such as high brittleness, low toughness, high shrinkage, and medium to high elastic modulus.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for preparing high-performance concrete, the method of which is as follows:

[0007] S1: Place the fine aggregate and fiber into the preparation device and premix for 30 seconds;

[0008] S2: Add coarse aggregate, expansion agent, cement, fly ash, water, and admixture in sequence, and wet mix for 90 seconds to obtain high-performance concrete.

[0009] In the above scheme, preferably, the cement is medium-low heat cement; the fly ash is Class F Grade I fly ash; the fine aggregate is artificial medium sand; the coarse aggregate is crushed stone; the admixture is a high-performance water-reducing agent; and the expansion agent has an expansion period of 14-28 days.

[0010] The fiber is basalt fiber with an elastic modulus ≥30GPa and a density of 2.5-2.7g / cm3.

[0011] In the above scheme, preferably, the fiber volume ratio should reach 1‰-2‰, the fiber length should be 1 / 3-1 / 2 of the maximum particle size of concrete, the diameter should be between 0.2-0.8mm, and the length-to-diameter ratio should be set between 100-300.

[0012] In the above scheme, preferably, the high-performance concrete is made of the following components by weight: water: 100-200 parts, cement: 200-300 parts, fly ash: 50-100 parts, expansion agent: 20-40 parts, fine aggregate: 400-700 parts, coarse aggregate: 600-1400 parts, fiber: 1-5 parts, and admixture: 1-2 parts.

[0013] In the above scheme, preferably, the dosage of the expansive agent is determined by first performing a restricted expansion rate curve of ordinary concrete, and ensuring that the expansion generated by the expansive agent matches the shrinkage generated by the concrete.

[0014] In the above scheme, a preferred high-performance concrete preparation device includes a mixing pot and a frame for mixing materials;

[0015] A telescopic cylinder for providing fibers is slidably provided at the bottom of the mixing tank;

[0016] The outer wall of the telescopic cylinder is provided with a groove channel along the axial direction, and a door panel is rotatably installed on the groove channel;

[0017] The door panel extends toward one end of the telescopic cylinder and is provided with a swing arm;

[0018] The mixing tank body is evenly provided with a number of drive pins that cooperate with the swing arm.

[0019] After the telescopic cylinder is placed inside the mixing pot, the mixing pot rotates relative to the telescopic cylinder, and the swing arm swings through the drive pin to open and close the door panel. The fibers fall into the mixing pot through the intermittent opening and closing of the door panel.

[0020] In the above scheme, preferably, elastic elements connected to the telescopic cylinder are symmetrically provided on both sides of the swing arm;

[0021] The telescopic cylinder is provided with a connecting part, and the frame is provided with a drive module that is connected to the connecting part and used to drive the telescopic cylinder to slide.

[0022] In the above scheme, preferably, the telescopic cylinder is provided with a track groove, and the stirring pot body is provided with a guide pin that cooperates with the track groove. When the telescopic cylinder slides relative to the stirring pot body, the telescopic cylinder rotates through the track groove, thereby enabling the trough channel to rotate.

[0023] In the above scheme, preferably, the trajectory groove includes a spiral groove and guide grooves at both ends of the spiral groove, and the telescopic cylinder is provided with an annular groove connected to the guide groove. The telescopic cylinder achieves relative rotation with the stirring pot body through the cooperation of the annular groove and the guide pin.

[0024] In the above scheme, preferably, the drive module is rotatably connected to the connecting part, the connecting part is provided with a positioning plate, the frame is provided with a first positioning pin and a second positioning pin that cooperate with the positioning plate to fix the drive module and the connecting part relatively, and the positioning plate is provided with positioning holes.

[0025] The beneficial effects of this invention are as follows: This invention provides a method for preparing high-performance concrete. By selecting the types of raw materials and determining the mixing method, a concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" is provided. This concrete improves the ultimate tensile strength of concrete by 20% to 30%, increases the flexural strength of concrete by 10% to 20%, reduces concrete shrinkage by 300 to 600 × 10⁻⁶, and reduces the elastic modulus of concrete by 15% to 20%.

[0026] Meanwhile, a concrete preparation device is provided, which solves the dust problem when the fiber is added. The fiber is mixed with fine aggregate through a linear intermittent addition method, which improves the uniformity of mixing and prevents the fiber from clumping after mixing, thus greatly improving the mixing quality and performance of concrete. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of the preparation device of the present invention.

[0028] Figure 2 This is a cross-sectional view of the preparation apparatus of the present invention.

[0029] Figure 3 This is a schematic diagram of the three-dimensional structure of the telescopic cylinder of the present invention.

[0030] Figure 4 This is a three-dimensional structural diagram of the left side of the telescopic cylinder of the present invention.

[0031] Figure 5 This is a schematic diagram of the three-dimensional structure of the mixing pot body of the present invention. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: See also Figures 1-5 .

[0033] A method for preparing high-performance concrete, the method is as follows:

[0034] S1: Place the fine aggregate and fiber into the preparation device and premix for 30 seconds;

[0035] S2: Add coarse aggregate, expansion agent, cement, fly ash, water, and admixture in sequence, and wet mix for 90 seconds to obtain high-performance concrete.

[0036] The cement is medium-low heat cement; the fly ash is Class F Grade I fly ash; the fine aggregate is artificial medium sand; the coarse aggregate is crushed stone; the admixture is a high-performance water-reducing agent; and the expansion agent has an expansion period of 14-28 days.

[0037] The fiber is basalt fiber with an elastic modulus ≥30GPa and a density of 2.5-2.7g / cm3.

[0038] The fiber volume ratio should reach 1‰-2‰, the fiber length should be 1 / 3-1 / 2 of the maximum particle size of concrete, the diameter should be between 0.2-0.8mm, and the aspect ratio should be set between 100-300.

[0039] The high-performance concrete is made from the following components by weight: water: 100-200 parts, cement: 200-300 parts, fly ash: 50-100 parts, expansion agent: 20-40 parts, fine aggregate: 400-700 parts, coarse aggregate: 600-1400 parts, fiber: 1-5 parts, admixture: 1-2 parts;

[0040] The number of parts can be replaced by a mass unit. That is, after setting the total mass of the concrete after mixing, the mass of different components is determined according to the number of parts. Then, the above components are mixed through steps S1 and S2 to produce high-performance concrete.

[0041] The determination of the dosage of the expansive agent is as follows: First, the restricted expansion rate curve of ordinary concrete is obtained, and the expansion generated by the expansive agent is matched with the shrinkage generated by the concrete.

[0042] The high-performance concrete produced by mixing the above components increases the ultimate tensile strength of concrete by 20% to 30%, increases the flexural strength of concrete by 10% to 20%, reduces the shrinkage of concrete by 300 to 600 × 10⁻⁶, and reduces the elastic modulus of concrete by 15% to 20%.

[0043] In this embodiment, during the mixing process in step S1, the fine aggregate and fiber are prone to uneven mixing. Furthermore, during conventional mixing, the fiber is very easy to clump together when poured into the mixing pot, and it generates a lot of dust. Therefore, this embodiment also provides a high-performance concrete preparation device.

[0044] The concrete preparation device includes a mixing pot 1 and a frame 2 for mixing materials; that is, the mixing of fine aggregate and fiber in step S1 is carried out in the mixing pot 1. The mixing pot 1 is preferably a mixing tank with spiral blades on the inner wall, which is provided with a material port 106. Mixing and discharging can be achieved by changing the rotation direction of the mixing tank. This is the prior art and will not be described in detail here.

[0045] The bottom of the mixing tank 1 is slidably provided with a telescopic cylinder 101 for providing fibers, and the fibers are pre-loaded into the telescopic cylinder 101;

[0046] The outer wall of the telescopic cylinder 101 is provided with a groove channel 102 along the axial direction, such as Figures 1-4 As shown, a door panel 103 is rotatably mounted on the trough channel 102. When filling fibers, the door panel 103 is manually rotated to open the door panel 103, and a certain mass of fibers is loaded into the telescopic cylinder 101 through the gap between the door panel 103 and the trough channel 102. Then the door panel 103 is closed.

[0047] The mixing pot body 1 includes a material inlet 106, through which fine aggregate is loaded into the mixing pot body 1. The telescopic cylinder 101 is slidably disposed within the bottom wall of the mixing pot body 1 on the side away from the material inlet 106. The bottom of the mixing pot body 1 has a sliding hole that mates with the telescopic cylinder 101. One end of the telescopic cylinder 101 passes through the sliding hole into the mixing pot body 1 and has a limiting plate at its end. Initially, the left side of the telescopic cylinder 101 is outside the mixing pot body 1, and the right end abuts against the mixing pot body 1 via the limiting plate. Figure 2 As shown.

[0048] When the telescopic cylinder 101 is in Figures 1-2 In the indicated state, the trough channel 102 is located directly above the telescopic cylinder 101. The two ends of the door panel 103 are rotatably mounted at both ends of the trough channel 102. The left end of the door panel 103 passes through the wall of the telescopic cylinder 101 via a pivot and a swing arm 104 is fixed outside the telescopic cylinder 101. At this time, the door panel 103 can be opened by manually swinging the swing arm 104 to any side, so that the trough channel 102 is opened and the fibers are filled into the telescopic cylinder 101 through the trough channel 102.

[0049] The telescopic cylinder 101 is fixedly provided with a connecting part 3 on its left end face. The frame 2 is provided with a drive module connected to the connecting part 3. The drive module can be a linear module or a push rod. The push rod can be a push rod with different drive sources, such as pneumatic, electric or hydraulic. Its main purpose is to drive the telescopic cylinder 101 to slide laterally back and forth relative to the stirring pot 2.

[0050] The upper end of the swing arm 104 is set higher than the outer edge of the telescopic cylinder 101, and its two sides are connected to the left outer wall of the telescopic cylinder 101 through the same elastic element. The telescopic cylinder 101 has symmetrical connecting columns on its outer wall. Initially, the elastic elements on both sides synchronously stretch the swing arm 104 to keep it in a vertical state. That is, in the natural state, the door panel 103 is in a closed state in cooperation with the trough channel 102. When the swing arm 104 swings to either side, the door panel 103 can open the trough channel 102 to realize material feeding and discharging. When the force applied to the swing arm 104 disappears, the swing arm 104 automatically resets through the elastic elements on both sides.

[0051] To ensure that after the telescopic cylinder 101 is slid laterally into the mixing pot 1, the trough channel 102 is in a vertically downward state and can be opened intermittently, in this embodiment, a track groove 4 is provided on the telescopic cylinder 101. Figures 3-4 As shown, the trajectory groove 4 includes a spiral groove 402 and guide grooves 403 provided at both ends of the spiral groove 402. The spiral angle of the spiral groove 402 is preferably 180°. The direction of the guide groove 403 is the same as the axis of the telescopic cylinder 101. The outer walls at both ends of the telescopic cylinder 101 are provided with annular grooves 404 connected to the guide grooves 403.

[0052] The sliding hole wall of the mixing pot body 1 that mates with the telescopic cylinder 101 is provided with a guide pin 401 that mates with the aforementioned track groove 4. That is, the end of the guide pin 401 is placed inside the track groove 401. Initially, that is, in Figure 1-2 In the state shown, the guide pin 401 engages with the annular groove 404 at the right end of the telescopic cylinder 101. When the telescopic cylinder 101 is stationary, the stirring pot 1 can achieve relative rotation with the telescopic cylinder 101 through the engagement of the guide pin 401 and the annular groove 404.

[0053] In the initial state, the guide pin 401 is located at the junction a1 of the guide groove 403 and the annular groove 404 on the right side of the telescopic cylinder 101, as shown below. Figure 3 As shown, after the fiber is filled into the telescopic cylinder 101, the telescopic cylinder 101 is driven to slide laterally by the drive module. At this time, the guide groove 103 on the right side of the telescopic cylinder 101 cooperates with the guide pin 401, and enters the spiral groove 402 after being connected by the guide groove 103. The telescopic cylinder 101 rotates under the spiral guidance of the guide pin 401 and the spiral groove 402, and rotates 180° through the spiral groove 402. That is, the telescopic cylinder 101 rotates itself at the same time as it is pushed into the mixing pot 1. After rotation, the groove channel 102 is in a vertically downward state, and the guide pin 401 is located at the connection point a2 between the telescopic cylinder 101 and the left guide groove 103, as shown. Figure 4 As shown.

[0054] The mixing pot body 1 has a plurality of drive pins 105 evenly arranged on the outer left side wall, which cooperate with the swing arm 104. The drive pins 105 are arranged in a circumferential array. When the telescopic cylinder 101 slides into the mixing pot body 1, the guide pin 401 slides into the guide groove 103 on the left side of the telescopic cylinder 101. At this time, the swing arm 104 is between adjacent drive pins 105. Then, the telescopic cylinder 101 is in a relatively fixed state. After the fine aggregate is filled into the mixing pot body 1, the mixing pot body 1 is driven to rotate relative to the telescopic cylinder 101. After the mixing pot body 1 rotates relative to the telescopic cylinder 101, the swing arm 104 swings through the drive pins 105 to realize the opening and closing of the door panel 103. The fiber falls intermittently into the mixing pot body 1 in a straight line through the opening and closing of the door panel 103 and is mixed evenly with the fine aggregate in the mixing pot body 1.

[0055] To ensure that the telescopic cylinder 101 remains stationary when the mixing pot body 1 rotates, and is rotatable when it extends or retracts relative to the mixing pot body 1, in this embodiment, the drive module is rotatably connected to the connecting part 3. This rotation can be achieved through a plane bearing or a rotating snap-fit ​​plate, and a positioning plate 301 is provided on the connecting part 3. Figures 1-4 As shown, the positioning plate 301 is in Figure 1 When shown, it is in a vertically downward state, and the lower end of the positioning plate 301 is provided with a positioning hole 302; the frame 2 is provided with a first positioning pin 201 and a second positioning pin 202 that cooperate with the positioning hole 302 of the positioning plate 301 to fix the drive module and the connecting part 3 relatively.

[0056] The first positioning pin 201 and the second positioning pin 202 are spatially set at 180°. Initially, the positioning plate 301 engages with the first positioning pin 201, and at this time, the telescopic cylinder 101 is radially fixed relative to the frame 2. When the drive module drives the telescopic cylinder 101 to slide, the telescopic cylinder 101 first slides laterally through the guide groove 401 on the right side, causing the positioning plate 301 to disengage from the first positioning pin 201. Subsequently, after the telescopic cylinder 101 rotates 180° through the spiral groove 402, the positioning plate 301... When 01 is in a vertically upward position, the telescopic cylinder 101 slides laterally through the guide groove 401 on the left side, causing the positioning hole 302 on the positioning plate 301 to slide into the second positioning pin 202 for engagement, thereby fixing the telescopic cylinder 101 radially relative to the frame 2. That is, when the telescopic cylinder 101 and the mixing pot body 1 are in telescopic engagement, at both ends, its radial direction is fixed to the frame 2. In this state, the mixing pot body 1 can achieve relative rotation with the telescopic cylinder 101 through the engagement of the guide pin 401 and the annular groove 404.

[0057] A method for preparing concrete using a high-performance concrete preparation device as described above:

[0058] T1: Load the fine aggregate into the mixing pot 1 through the material inlet 106, and rotate it 3-5 times to spread the fine aggregate evenly on the inner wall of the mixing pot 1.

[0059] T2: When the mixing pot 1 is stationary, open the door panel 103 and fill the fiber into the telescopic cylinder 101 through the trough channel 102. Then the door panel 103 closes automatically and the telescopic cylinder 101 is pushed horizontally into the mixing pot 1 by the drive module. During the horizontal pushing process, the telescopic cylinder 101 rotates 180° synchronously so that the trough channel 102 is in a vertical downward state.

[0060] T3: During the T2 process, when the drive module drives the telescopic cylinder 101, the part of the spiral groove 402 that engages with the guide pin 401 can slide back and forth through the drive module, so that the telescopic cylinder 101 can slide laterally and rotate back and forth at the same time, thereby evenly spreading the fibers inside the telescopic cylinder 101 on the inner wall of the telescopic cylinder 101.

[0061] T4: After the telescopic cylinder 101 is pushed into the mixing pot 1, the telescopic cylinder 101 is fixed relative to the frame 2 by the cooperation of the positioning plate 301 and the second positioning pin 202. Then, the mixing pot 1 is driven to rotate relative to the telescopic cylinder 101. While the mixing pot 1 is rotating, the drive pin 105 cooperates with the swing arm 104 in turn, so that the door panel 103 opens and closes intermittently, so that the fiber is evenly sprinkled into the fine aggregate in the mixing pot 1 in a straight line, and the blades on the inner wall of the mixing pot 1 are used to mix the fine aggregate and fiber evenly.

[0062] T5: During the T4 process, the mixing pot 1 rotates for 30 seconds and then stops. Subsequently, the telescopic cylinder 101 is reset through the drive module, and coarse aggregate, expansion agent, cement, fly ash, water, and admixtures are poured into the mixing pot 1 through the material port 106. Wet mixing is carried out for 90 seconds. After the materials are evenly mixed, high-performance concrete can be obtained.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-performance concrete preparation device, characterized in that: Includes a mixing pot body (1) for mixing materials and a frame (2); The bottom of the mixing pot body (1) is slidably provided with a telescopic cylinder (101) for providing fibers. The telescopic cylinder (101) has a groove channel (102) on its outer wall along the axial direction, and a door panel (103) is rotatably mounted on the groove channel (102). The door panel (103) is provided with a swing arm (104) extending towards one end of the telescopic cylinder (101). The stirring pot body (1) is evenly provided with a number of drive pins (105) that cooperate with the swing arm (104). After the telescopic cylinder (101) is placed inside the mixing pot (1), the mixing pot (1) rotates relative to the telescopic cylinder (101) and then the swing arm (104) swings through the drive pin (105) to realize the opening and closing of the door panel (103). The fiber falls into the mixing pot (1) intermittently through the opening and closing of the door panel (103). The swing arm (104) is symmetrically provided with elastic elements connected to the telescopic cylinder (101) on both sides; The telescopic cylinder (101) is provided with a track groove (4), and the stirring pot body (1) is provided with a guide pin (401) that cooperates with the track groove (4). When the telescopic cylinder (101) slides relative to the stirring pot body (1), the telescopic cylinder (101) rotates through the track groove (4), thereby causing the trough channel (102) to rotate. The trajectory groove (4) includes a spiral groove (402) and guide grooves (403) at both ends of the spiral groove (402). The telescopic cylinder (101) is provided with an annular groove (404) connected to the guide groove (403). The telescopic cylinder (101) achieves relative rotation with the stirring pot body (1) through the cooperation of the annular groove (404) and the guide pin (401).

2. The high-performance concrete preparation device according to claim 1, characterized in that: The telescopic cylinder (101) is provided with a connecting part (3), and the frame (2) is provided with a drive module connected to the connecting part (3) and used to drive the telescopic cylinder (101) to slide.

3. The high-performance concrete preparation device according to claim 2, characterized in that: The drive module is rotatably connected to the connecting part (3). The connecting part (3) is provided with a positioning plate (301). The frame (2) is provided with a first positioning pin (201) and a second positioning pin (202) that cooperate with the positioning plate (301) to fix the drive module and the connecting part (3) relatively. The positioning plate (301) is provided with a positioning hole (302).

4. A method for preparing concrete using the high-performance concrete preparation device as described in claim 1, characterized in that: The method is as follows: S1: Place the fine aggregate and fiber into the preparation device and premix for 30 seconds; S2: Add coarse aggregate, expansion agent, cement, fly ash, water, and admixture in sequence, and wet mix for 90 seconds to obtain high-performance concrete.

5. The preparation method according to claim 4, characterized in that: The cement is medium-low heat cement; the fly ash is Class F Grade I fly ash; the fine aggregate is artificial medium sand; the coarse aggregate is crushed stone; the admixture is a high-performance water-reducing agent; and the expansion agent has an expansion period of 14-28 days. The fiber is basalt fiber with an elastic modulus ≥30GPa and a density of 2.5-2.7g / cm3.

6. The preparation method according to claim 4, characterized in that: The fiber volume ratio should reach 1‰-2‰, the fiber length should be 1 / 3-1 / 2 of the maximum particle size of concrete, the diameter should be between 0.2-0.8mm, and the aspect ratio should be set between 100-300.

7. The preparation method according to claim 4, characterized in that: The high-performance concrete is made from the following components by weight: water: 100-200 parts, cement: 200-300 parts, fly ash: 50-100 parts, expansion agent: 20-40 parts, fine aggregate: 400-700 parts, coarse aggregate: 600-1400 parts, fiber: 1-5 parts, and admixture: 1-2 parts.

8. The preparation method according to claim 4, characterized in that: The determination of the dosage of the expansive agent is as follows: First, the restricted expansion rate curve of ordinary concrete is obtained, and the expansion generated by the expansive agent is matched with the shrinkage generated by the concrete.

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