Preparation method and preparation device of high-performance concrete

Abstract

The invention discloses a preparation method and a preparation device of high-performance concrete. The preparation method comprises the following steps: premixing fine aggregate and fibers in the preparation device for 30 seconds; sequentially adding the coarse aggregate, the expanding agent, the cement, the fly ash, the water and the additive, and carrying out wet mixing for 90s to obtain the high-performance concrete, according to the preparation method of the high-performance concrete provided by the invention, the concrete with high ductility, high toughness, low shrinkage and low elastic modulus is provided by selecting the types of the raw materials and determining a mixing method; meanwhile, the invention provides a concrete preparation device, the problem of dust raising during throwing of the fibers is solved, the fibers are mixed with the fine aggregate in a linear intermittent throwing mode, and the mixing uniformity is improved, so that the fibers are prevented from caking after being mixed, and the mixing quality and the mixing performance of the concrete are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete preparation, in particular to a high performance concrete preparation method and a preparation device. Background Art

[0002] Faced concrete is widely used in water conservancy and hydropower projects. It plays a role in protecting the main structure of the project and resisting water penetration, and has an important impact on the safety and durability of the project structure.

[0003] Due to the characteristics of large-scale construction of panel concrete in a short period of time, the accumulation of shrinkage deformation in the length direction during the setting and hardening of concrete will cause large tensile stress. When the length of the later poured panel concrete is large (more than 100 meters) and is subject to the restraining force of the first poured concrete, the tensile stress generated often exceeds the tensile strength of the concrete itself, resulting in concrete cracking and damage. Therefore, in order to avoid the occurrence of damage, engineers need to develop a high-performance concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" to avoid cracking and damage.

[0004] However, since concrete is a brittle material with cement as the binder, it has high compressive strength but low tensile strength (about 1 / 10 of the compressive strength), a large number of micro cracks and pores inside, and shrinkage during setting, drying and temperature shrinkage during the hardening process. Ordinary concrete often has the characteristics of "high brittleness, low toughness, high shrinkage, and medium-high elastic modulus". Therefore, it is very important to develop a high-performance concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" to avoid cracking and damage. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method and device for preparing high-performance concrete, which solves the defects of the prior concrete such as high brittleness, low toughness, high shrinkage and medium-high elastic modulus according to the types of raw materials selected and the mixing method.

[0006] In order to solve the above technical problems, the present invention is solved by the following technical solutions: a method for preparing high performance concrete, the method is as follows: S1: Premix fine aggregate and fiber into the preparation device for 30 seconds; S2: Add coarse aggregate, expansive agent, cement, fly ash, water and admixture in sequence, wet mix for 90 seconds to obtain high performance concrete.

[0007] 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; the expansion agent has an expansion period of 14-28 days; The fiber is basalt fiber with an elastic modulus ≥ 30 GPa and a density of 2.5 - 2.7 g / cm3.

[0008] In the above solution, preferably, the volume ratio of the fiber should reach 1‰ - 2‰, the fiber length is 1 / 3 - 1 / 2 of the maximum particle size of the concrete, the diameter is between 0.2 - 0.8 mm, and the aspect ratio is set between 100 - 300.

[0009] In the above solution, 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, admixture: 1 - 2 parts.

[0010] In the above solution, preferably, for the determination of the dosage of the expansion agent: first, a restricted expansion rate curve of ordinary concrete is carried out, and the expansion generated by the expansion agent matches the shrinkage generated by the concrete.

[0011] In the above solution, preferably, a high-performance concrete preparation device includes a mixing pot body for mixing materials and a frame; A telescopic cylinder for providing fiber is slidably arranged at the bottom of the mixing pot body; A groove channel is arranged on the outer wall of the telescopic cylinder along the axial direction, and a door panel is rotatably arranged on the groove channel; A swing arm extends from the door panel towards one end of the telescopic cylinder; A number of driving pins cooperating with the swing arm are evenly arranged on the mixing pot body; After the telescopic cylinder is placed in the mixing pot body, when the mixing pot body rotates relative to the telescopic cylinder, the swing arm swings through the driving pins to realize the opening and closing of the door body, and the fiber intermittently falls into the mixing pot body through the opening and closing of the door body.

[0012] In the above solution, preferably, elastic members connected to the telescopic cylinder are symmetrically arranged on both sides of the swing arm; A connecting portion is arranged on the telescopic cylinder, and a driving module connected to the connecting portion and used to drive the telescopic cylinder to slide is arranged on the frame.

[0013] In the above solution, preferably, a track groove is arranged on the telescopic cylinder, and a guiding pin cooperating with the track groove is arranged on the mixing pot body. When the telescopic cylinder slides relative to the mixing pot body, the telescopic cylinder rotates through the track groove, so that the groove channel rotates.

[0014] In the above solution, preferably, the track groove includes a spiral groove and guiding grooves arranged at both ends of the spiral groove. An annular groove connected to the guiding grooves is arranged on the telescopic cylinder, and the telescopic cylinder realizes its relative rotation with the mixing pot body through the cooperation of the annular groove and the guiding pin.

[0015] In the above solution, preferably, the driving module is rotatably connected to the connecting part. A positioning plate is provided on the connecting part, and a first positioning pin and a second positioning pin that cooperate with the positioning plate to relatively fix the driving module and the connecting part are provided on the frame. Positioning holes are provided on the positioning plate.

[0016] The beneficial effects of the present invention are as follows: The present invention provides a method for preparing high-performance concrete. By selecting the types of raw materials and determining the mixing method, a kind of concrete with "high ductility, high toughness, low shrinkage, and low elastic modulus" is provided; this concrete provides a concrete ultimate tensile value of 20% - 30%, increases the flexural strength of the concrete by 10% - 20%, reduces the concrete shrinkage by 300 - 600×10-6, and reduces the elastic modulus of the concrete by 15% - 20%; At the same time, a preparation device for concrete is provided, which solves the problem of dust flying during the feeding of fibers. And the fibers are mixed with fine aggregates in a linear intermittent feeding manner, improving the mixing uniformity, thereby preventing the fibers from agglomerating after mixing and greatly improving the mixing quality and mixing performance of the concrete. Description of the Drawings

[0017] Figure 1 It is a three-dimensional structural schematic diagram of the preparation device of the present invention.

[0018] Figure 2 It is a cross-sectional view of the preparation device of the present invention.

[0019] Figure 3 It is a three-dimensional structural schematic diagram of the telescopic cylinder of the present invention.

[0020] Figure 4 It is a left three-dimensional structural schematic diagram of the telescopic cylinder of the present invention.

[0021] Figure 5 It is a three-dimensional structural schematic diagram of the mixing pot body of the present invention. Detailed Embodiments

[0022] The following further describes the present invention in detail in conjunction with the drawings and specific embodiments: See Figures 1-5 .

[0023] A method for preparing high-performance concrete is as follows: S1: Put fine aggregates and fibers into the preparation device for premixing for 30 s; S2: Add coarse aggregates, expansion agent, cement, fly ash, water, and admixtures in sequence and wet mix for 90 s to obtain high-performance concrete.

[0024] 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 reducer; the expansion agent has an expansion period of 14 - 28 days; The fiber is basalt fiber with an elastic modulus ≥ 30 GPa and a density of 2.5 - 2.7 g / cm3.

[0025] The fiber volume ratio should reach 1‰ - 2‰, the fiber length is 1 / 3 - 1 / 2 of the maximum particle size of the concrete, the diameter is between 0.2 - 0.8 mm, and the length-diameter ratio is set between 100 - 300.

[0026] The high-performance concrete is made up 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, admixture: 1 - 2 parts; Among them, the parts can be replaced by mass units, that is, after setting the total mass of the concrete after mixing, the masses of different components are determined according to the parts, and then the above components are mixed through steps S1 and S2 to make high-performance concrete.

[0027] The determination of the dosage of the expansion agent: First, conduct a restricted expansion rate curve of ordinary concrete, and the expansion generated by the expansion agent matches the shrinkage generated by the concrete.

[0028] The high-performance concrete after mixing by the above components increases the ultimate tensile value of the concrete by 20% - 30%, increases the flexural strength of the concrete by 10% - 20%, reduces the concrete shrinkage by 300 - 600×10-6, and reduces the elastic modulus of the concrete by 15% - 20%.

[0029] In this embodiment, during the mixing process of step S1, it is easy to produce uneven mixing of the fine aggregate and the fiber during mixing, and during conventional mixing, when the fiber is poured into the mixing pot body as a whole, it is extremely easy to form lumps and there is a large amount of dust. Therefore, this embodiment also provides a high-performance concrete preparation device.

[0030] The concrete preparation device includes a mixing pot body 1 for mixing materials and a frame 2; that is, the mixing of the fine aggregate and the fiber in step S1 is carried out in the mixing pot body 1. The mixing pot body 1 preferably uses a mixing barrel with spiral blades arranged on the inner wall, which is provided with a material port 106. After changing the rotation direction of the mixing barrel, stirring and discharging can be achieved. This is prior art and will not be elaborated here.

[0031] A telescopic cylinder 101 for providing fiber is slidably arranged at the bottom of the mixing pot body 1, and the fiber is pre-loaded into the telescopic cylinder 101; A groove channel 102 is provided on the outer wall of the telescopic cylinder 101 along the axial direction, as Figures 1-4 shown. A door panel 103 is rotatably arranged on the groove channel 102. When loading fibers, the door panel 103 is manually rotated to open it, and a certain mass of fibers is loaded into the telescopic cylinder 101 through the gap between the door panel 103 and the groove channel 102, and then the door panel 103 is closed.

[0032] The mixing pot body 1 includes a material inlet 106. Fine aggregate is loaded into the mixing pot body 1 through the material inlet 106. The telescopic cylinder 101 is slidably arranged in the bottom wall of the mixing pot body 1 on the side away from the material inlet 106, and a sliding hole matching with the telescopic cylinder 101 is provided at the bottom of the mixing pot body 1. One end of the telescopic cylinder 101 passes through the mixing pot body 1 through the sliding hole and a limiting plate is arranged at the end. Initially, the left part of the telescopic cylinder 101 is placed outside the mixing pot body 1, and the right end is in contact with the mixing pot body 1 through the limiting plate, as Figure 2 shown.

[0033] When the telescopic cylinder 101 is in the Figures 1-2 shown state, the groove channel 102 is located directly above the telescopic cylinder 101. Both ends of the door panel 103 are rotatably arranged at both ends of the groove channel 102. The left end of the door panel 103 passes through the wall of the telescopic cylinder 101 through a rotating shaft and a swing arm 104 is fixedly arranged outside the telescopic cylinder 101. At this time, the door panel 103 is manually swung to either side through the swing arm 104 to open it, so that the groove channel 102 is opened, and fibers are loaded into the telescopic cylinder 101 through the groove channel 102.

[0034] A connecting part 3 is fixedly arranged on the left end face of the telescopic cylinder 101, and a driving module connected to the connecting part 3 is arranged on the frame 2. The driving module can adopt a linear module or a push rod. The above push rod can adopt push rods with different driving sources, such as pneumatic, electric or hydraulic, etc. Its main purpose is to drive the telescopic cylinder 101 to slide horizontally back and forth relative to the mixing pot body 2.

[0035] The upper end of the swing arm 104 is arranged higher than the outer edge of the telescopic cylinder 101, and both sides of it are connected to the left outer wall of the telescopic cylinder 101 through the same elastic parts. Connecting columns are symmetrically arranged on the outer wall of the telescopic cylinder 101. Initially, the elastic parts 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 matching with the groove channel 102. When the swing arm 104 swings to either side, the door panel 103 can be opened to open the groove channel 102 to realize feeding and discharging, and when the force applied to the swing arm 104 disappears, the swing arm 104 automatically resets through the elastic parts on both sides.

[0036] After the telescopic cylinder 101 slides horizontally and is placed inside the mixing pot body 1, the trough channel 102 is in a vertically downward state and can be intermittently opened. In this embodiment, a track groove 4 is provided on the telescopic cylinder 101, as follows Figures 3-4 As shown, the track groove 4 includes a spiral groove 402 and guiding grooves 403 provided at both ends of the spiral groove 402. The spiral angle of the spiral groove 402 is preferably 180°. The groove direction of the guiding groove 403 is the same as the axis of the telescopic cylinder 101. Annular grooves 404 connected to the guiding grooves 403 are provided on the outer walls at both ends of the telescopic cylinder 101.

[0037] A guiding pin 401 matching the above track groove 4 is provided on the hole wall of the sliding hole where the mixing pot body 1 cooperates with the telescopic cylinder 101, that is, the end of the guiding pin 401 is placed inside the track groove 401. Initially, that is, Figures 1-2 In the state shown, the guiding pin 401 cooperates with the annular groove 404 at the right end of the telescopic cylinder 101. At this time, when the telescopic cylinder 101 is stationary, the mixing pot body 1 can realize relative rotation with the telescopic cylinder 101 through the cooperation of the guiding pin 401 and the annular groove 404.

[0038] In the initial state, the guiding pin 401 is at the connection a1 between the guiding groove 403 on the right side of the telescopic cylinder 101 and the annular groove 404. As Figure 3 shown, at this time, after the fiber is loaded into the telescopic cylinder 101, the telescopic cylinder 101 is driven to slide horizontally by the driving module. At this time, the guiding groove 103 on the right side of the telescopic cylinder 101 cooperates with the guiding pin 401, and after passing through the connection of the guiding groove 103, it enters the spiral groove 402. The telescopic cylinder 101 rotates under the spiral guidance of the guiding pin 401 and the spiral groove 402. By rotating 180° through the spiral groove 402, that is, when the telescopic cylinder 101 is pushed into the mixing pot body 1, it rotates by itself. After rotation, the trough channel 102 is in a vertically downward state, and the guiding pin 401 is at the connection a2 between the telescopic cylinder 101 and the guiding groove 103 on the left side, as Figure 4 shown.

[0039] A number of driving pins 105 matching the swing arms 104 are evenly provided on the outer wall of the left side of the mixing pot body 1; the driving pins 105 are arranged in a circumferential array. When the telescopic cylinder 101 slides into the mixing pot body 1, the guiding pin 401 slides into the guiding groove 103 on the left side of the telescopic cylinder 101. At this time, the swing arm 104 is between adjacent driving pins 105. Subsequently, the telescopic cylinder 101 is in a relatively fixed state, and after fine aggregate is loaded 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 is swung through the driving pin 105 to realize the opening and closing of the door body 103. The fiber intermittently falls into the mixing pot body 1 in a straight line through the opening and closing of the door body 103 and is evenly mixed with the fine aggregate in the mixing pot body 1.

[0040] In order to make the telescopic cylinder 101 stationary when the mixing pot body 1 rotates and rotatable when the telescopic cylinder 101 expands and contracts relative to the mixing pot body 1, in this embodiment, the driving module is rotatably connected to the connecting portion 3, and its rotation can be realized in forms such as a plain bearing or a rotating clamping plate. And a positioning plate 301 is provided on the connecting portion 3. As Figures 1-4 shown, the positioning plate 301 is in a vertically downward state in the state shown in Figure 1 shown, and a positioning hole 302 is provided at the lower end of the positioning plate 301; a first positioning pin 201 and a second positioning pin 202 are provided on the frame 2 to cooperate with the positioning hole 302 of the positioning plate 301 to relatively fix the driving module and the connecting portion 3.

[0041] The first positioning pin 201 and the second positioning pin 202 are arranged at a spatial 180°. Initially, the positioning plate 301 cooperates with the first positioning pin 201. At this time, the telescopic cylinder 101 is in a state of being relatively fixed to the frame 2 in the radial direction. When the driving module drives the telescopic cylinder 101 to slide, the telescopic cylinder 101 first slides horizontally through the guiding groove 401 on the right side, so that the positioning plate 301 is disengaged from the first positioning pin 201. Subsequently, after the telescopic cylinder 101 rotates 180° through the spiral groove 402, the positioning plate 301 is in a vertically upward state. At this time, the telescopic cylinder 101 slides horizontally through the guiding groove 401 on the left side so that the positioning hole 302 on the positioning plate 301 slides onto the second positioning pin 202 for cooperation, realizing the fixation of the telescopic cylinder 101 relative to the frame 2 in the radial direction, that is, when the telescopic cylinder 101 expands and contracts with the mixing pot body 1, at both ends, it is in a state of being fixed to the frame 2 in the radial direction. In this state, the mixing pot body 1 can realize its relative rotation with the telescopic cylinder 101 through the cooperation of the guiding pin 401 and the annular groove 404.

[0042] A method for preparing concrete using a high-performance concrete preparation device as described above: T1: Load the fine aggregate into the mixing pot body 1 through the material port 106 and rotate it 3 - 5 times to evenly lay the fine aggregate on the inner wall of the mixing pot body 1; T2: The mixing pot body 1 is stationary. Open the door panel 103, load the fiber into the telescopic cylinder 101 through the trough channel 102, and then the door panel 103 automatically closes. Push the telescopic cylinder 101 horizontally into the mixing pot body 1 through the driving module. During the horizontal pushing process, the telescopic cylinder 101 rotates 180° synchronously so that the trough channel 102 is in a vertically downward state; T3: During the process of T2, when the driving module drives the telescopic cylinder 101, the part where the spiral groove 402 cooperates with the guiding pin 401 can reciprocally slide through the driving module, so that the telescopic cylinder 101 reciprocally rotates while sliding horizontally, thereby evenly laying the fiber in the telescopic cylinder 101 on the inner wall of the telescopic cylinder 101; T4: After the telescopic cylinder 101 is pushed into the mixing pot body 1, the telescopic cylinder 101 is relatively fixed to the machine frame 2 through the cooperation of the positioning plate 301 and the second positioning pin 202. Subsequently, the mixing pot body 1 is driven to rotate relative to the telescopic cylinder 101. While the mixing pot body 1 is rotating, the driving pins 105 cooperate with the swing arms 104 in sequence to intermittently open and close the door plate 103, evenly sprinkle the fibers in a straight line onto the fine aggregate in the mixing pot body 1, and cooperate with the blades on the inner wall of the mixing pot body 1 to evenly mix the fine aggregate and the fibers; T5: During the process of T4, after the mixing pot body 1 rotates for 30 s and then stops, the telescopic cylinder 101 is reset through the driving module, and coarse aggregate, expansive agent, cement, fly ash, water, and admixture are poured into the mixing pot body 1 through the material port 106, and wet mixed for 90 s. High-performance concrete can be obtained after the materials are evenly mixed.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

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

2. A method for preparing high performance concrete according to claim 1, 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; the expansion agent has an expansion period of 14-28 days; The fiber is basalt fiber with an elastic modulus of ≥30 GPa and a density of 2.5-2.7 g / cm3.

3. A method for preparing high performance concrete according to claim 1, 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.

4. A method for preparing high performance concrete according to claim 1, characterized in that: The high-performance concrete is made of the following components in weight fractions: 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.

5. A method for preparing high performance concrete according to claim 1, characterized in that: Determination of the amount of the expansive agent: First, the ordinary concrete limited expansion rate curve is carried out, and the expansion of the expansive agent matches the contraction of the concrete.

6. A device for preparing a high performance concrete according to claim 1, characterized in that: It comprises a stirring pot body (1) and a frame (2) for mixing materials; A telescopic cylinder (101) for providing fibers is slidably disposed at the bottom of the stirring pot body (1); The outer wall of the telescopic cylinder (101) is provided with a slot channel (102) along the axial direction, and a door panel (103) is rotatably provided on the slot channel (102); The door panel (103) is provided with a swing arm (104) extending toward one end of the telescopic cylinder (101); The stirring pot body (1) is evenly provided with a plurality of driving pins (105) that cooperate with the swing arm (104); After the telescopic cylinder (101) is placed in the stirring pot body (1), the stirring pot body (1) rotates relative to the telescopic cylinder (101), and the swing arm (104) swings through the driving pin (105) to achieve the opening and closing of the door body (103), and the fibers fall into the stirring pot body (1) through the intermittent opening and closing of the door body (103).

7. A high performance concrete preparation device according to claim 6, characterized in that: Elastic parts connected to the telescopic cylinder (101) are symmetrically provided on both sides of the swing arm (104); The telescopic cylinder (101) is provided with a connecting portion (3), and the frame (2) is provided with a driving module connected to the connecting portion (3) and used for driving the telescopic cylinder (101) to slide.

8. A high performance concrete preparation device according to claim 7, characterized in that: 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 matches the track groove (4). When the telescopic cylinder (101) slides relative to the stirring pot body (1), the track groove (4) enables the telescopic cylinder (101) to rotate, thereby enabling the tank body channel (102) to rotate.

9. A high performance concrete preparation device according to claim 8, characterized in that: The track groove (4) comprises a spiral groove (402) and guide grooves (403) provided at both ends of the spiral groove (402); an annular groove (404) connected to the guide groove (403) is provided on the telescopic cylinder (101); 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).

10. A high performance concrete preparation device according to claim 9, characterized in that: The driving module is rotatably connected to the connecting portion (3); a positioning plate (301) is provided on the connecting portion (3); a first positioning pin (201) and a second positioning pin (202) are provided on the frame (2) and cooperate with the positioning plate (301) to achieve relative fixation between the driving module and the connecting portion (3); and a positioning hole (302) is provided on the positioning plate (301).

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