Device and method for testing mechanical properties of waste concrete

Abstract

The invention discloses a waste concrete mechanical property testing device and method, the waste concrete mechanical property testing device comprises a foundation, a guide column, a movable plate, a turntable, a drilling mechanism, a placing mechanism and a pulling-out mechanism, and a clamp is fixed on the top surface of the foundation to clamp a waste concrete block; the guide column is vertically fixed on the top surface of the foundation; the movable plate is slidably connected to the guide columns. The turntable is rotationally connected to the bottom surface of the movable plate; the drilling mechanism is used for drilling the waste concrete blocks; the placing mechanism is used for placing expansion bolts in the drilled holes; the pulling-out mechanism pulls out the expansion bolt; the axes of the drilling mechanism, the placing mechanism and the pulling-out mechanism are arranged on the bottom face of the rotary disc in an isosceles triangle mode. The relation between the strength of the waste concrete and the torque, thrust and drilling speed of the drill bit and the relation between the peak pull-out force in the pull-out process of the expansion bolt and the strength of the waste concrete are established. The strength of the waste concrete is comprehensively evaluated through a drilling-in method and a pulling-out method, and the method is more accurate compared with the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete material property testing equipment, and more specifically to a waste concrete mechanical property testing device and a testing method. Background Art

[0002] There is a large amount of concrete demolition waste, and the storage of construction waste has had a huge impact on the environment. In recent years, scholars have crushed waste concrete into recycled aggregates and used them as raw materials to prepare concrete, which can not only reduce construction solid waste, but also reduce the exploitation of natural aggregate resources and alleviate environmental pressure. The service environment of concrete structures is complex. After long-term service, the mechanical properties of concrete deteriorate and the performance of recycled aggregates is difficult to guarantee. Most of the existing studies evaluate the performance of recycled aggregates.

[0003] For example, the invention patent application (application publication number CN 115147421 A, application publication date 2022.10.04) discloses a method for grading and evaluating recycled aggregates for construction waste recycling. By using image processing technology, wood chips and plastic impurities in recycled aggregates are identified and then graded and evaluated. Another example is the invention patent application (application publication number CN114925987 A, application publication date 2022.08.19) discloses a method for grading recycled crushed stone aggregates for concrete. The quality of recycled aggregates is classified by indicators such as strength loss, apparent density, crushing index and water absorption rate. The invention patent application (application publication number CN 104276775 A, application publication date 2015.01.14) discloses a grading and evaluation system for low-quality recycled aggregates. The performance of aggregates mixed with ordinary coarse and fine aggregates and low-quality recycled coarse and fine aggregates is evaluated. The evaluation indicators include crushing index, firmness, compressive strength ratio and water absorption rate. The utility model patent (authorization announcement number CN205949291 U, authorization announcement date 2017.02.15) discloses a recycled aggregate performance detection device, which detects the needle-like content and gradation of the recycled aggregate.

[0004] It can be seen from the above patents that there is currently a lack of evaluation methods for the mechanical properties of waste concrete itself. The performance of waste concrete cannot be accurately reflected by evaluating the properties of recycled aggregates, and the evaluation indicators for recycled aggregates are mostly reflected in GB / T 25177 "Recycled coarse aggregate for concrete" and GB / T 25176 "Recycled fine aggregate for concrete and mortar".

[0005] Currently, there is no method to evaluate the mechanical properties of waste concrete before processing recycled aggregates, rapid on-site testing is impossible, and there is a lack of corresponding mechanical property evaluation indicators.

[0006] Therefore, how to provide a waste concrete mechanical properties testing device and testing method that can accurately evaluate the mechanical properties of waste concrete is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] In view of this, the present invention provides a waste concrete mechanical properties testing device and testing method, aiming to solve the above technical problems.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A waste concrete mechanical properties testing device, comprising:

[0010] A foundation, wherein a clamp is fixed at the middle of the top surface of the foundation to clamp the waste concrete blocks;

[0011] Guide pillars, which are multiple and vertically fixed in an array around the top surface of the base;

[0012] A movable plate, the panel of which is vertically slidably connected to the plurality of guide pillars;

[0013] A turntable, the top surface of which is rotatably connected to the bottom surface of the movable plate;

[0014] A drilling mechanism, the drilling mechanism being fixed to the bottom surface of the turntable to drill holes in the waste concrete blocks;

[0015] A placing mechanism, the placing mechanism being fixed to the bottom surface of the turntable to place expansion bolts into the drilled holes;

[0016] A pulling mechanism, the pulling mechanism is fixed to the bottom surface of the rotating disk to pull out the expansion bolt;

[0017] The axes of the drilling mechanism, the placing mechanism and the pulling mechanism are arranged in an isosceles triangle on the bottom surface of the turntable.

[0018] The beneficial effect of the above technical solution is that the drilling mechanism drills holes in the waste concrete blocks, the placement mechanism places the expansion bolts in the drilled holes, and the extraction mechanism pulls the expansion bolts out of the holes. The strength of the waste concrete is comprehensively evaluated by the drilling method and the extraction method, which is more accurate than the existing technology.

[0019] Preferably, the drilling mechanism includes a first connecting rod and a drill bit, the first connecting rod is vertically fixed to the bottom surface of the turntable, one end of the drill bit is hinged to the end of the first connecting rod away from the turntable through a first hinge ring, and a drilling torque sensor, a drilling pressure sensor and a drilling displacement sensor are fixed to the outer wall of the drill bit. When not in use, the drill bit can be folded 90 degrees without affecting the operation of the placement mechanism and the extraction mechanism. During the drilling process, the drill bit records the curves of torque and pressure changes over time through the drilling torque sensor and the drilling pressure sensor, and the drilling displacement sensor records the displacement of the drill bit, so that the drilling depth can be accurately measured.

[0020] Preferably, the placement mechanism includes a second connecting rod and a placement robotic arm, the second connecting rod is vertically fixed to the bottom surface of the turntable, one end of the placement robotic arm is hinged to the end of the second connecting rod away from the turntable through a second hinge ring, and a placement torque sensor and a placement pressure sensor are fixed on the placement robotic arm.

[0021] Preferably, the pulling mechanism includes a third connecting rod and a pulling mechanical arm, the third connecting rod is vertically fixed to the bottom surface of the turntable, one end of the pulling mechanical arm is hinged to the end of the third connecting rod away from the turntable through a third hinge ring, and a pulling tension sensor is fixed on the pulling mechanical arm.

[0022] The beneficial effect of the above technical solution is that when the drilling mechanism, placement mechanism or extraction mechanism starts working, the working arm of the mechanism that needs to work contacts the abandoned concrete block for operation, and the working arms of the other two mechanisms can be folded 90 degrees through the intersection ring to avoid the working mechanism so as not to affect each other.

[0023] Preferably, a plurality of fixed mechanical arms are fixed on the top surface of the foundation relative to the peripheral side of the clamp to fix the waste concrete block. The waste concrete block is clamped by the clamp to ensure its stability, and the fixed mechanical arms are used to fix the waste concrete block to prevent the waste concrete block from moving during the drilling process, thereby preventing the occurrence of an inclined hole or drilling failure.

[0024] Preferably, there are four guide pillars arranged at the four corners of the top surface of the foundation, the guide pillars include a base and a ball screw, the base is fixed to the top surface of the foundation, the ball screw is rotatably connected to the top surface of the base, a threaded sleeve is threadedly connected to the ball screw, and an engaging hole is provided on the panel of the movable plate corresponding to the ball screw and is engaged with the threaded sleeve to move up and down along the ball screw with the threaded sleeve. The screws on the four guide pillars rotate synchronously, driving the four threaded sleeves to move up and down synchronously along the screws, thereby realizing the up and down movement of the movable plate.

[0025] Preferably, a motor is fixed on the top surface of the movable plate, and the output shaft of the motor passes through the panel of the movable plate and is fixed to the turntable to drive the turntable to rotate. The motor drives the turntable to rotate, and the rotation of the turntable switches the drilling mechanism, the placement mechanism or the extraction mechanism to perform corresponding tests.

[0026] Preferably, the motor, the drilling mechanism, the placing mechanism, and the pulling mechanism are all connected to a control system through communication. The automation of the test process is improved through control of the control system.

[0027] The present invention also provides a method for testing the mechanical properties of waste concrete, which uses the performance testing device in the above technical solution to perform performance testing on waste concrete blocks, specifically comprising the following steps:

[0028] S1. Clamp the waste concrete block on the fixture, and fix the waste concrete block by fixing the mechanical arm.

[0029] S2, moving the movable plate downward, the drilling mechanism drills holes in the waste concrete blocks, and records the curves of drilling torque and drilling pressure changing with time;

[0030] The top plate moves downward along the column guide column to the surface of the waste concrete block, and the mechanical arms of the placement mechanism and the extraction mechanism rotate 90 degrees around the second hinge ring and the third hinge ring respectively to avoid contact between the mechanical arms of the placement mechanism and the extraction mechanism and the waste concrete block during drilling;

[0031] The drill bit starts drilling, and the torque sensor and pressure sensor record the curves of torque and pressure changing with time, respectively, and upload them to the control system. When the displacement value recorded by the drilling displacement sensor reaches 30mm, the drill bit stops working, and the movable plate moves upward along the guide column to the appropriate position, and the drilling work is completed;

[0032] The work done by the drill bit during drilling includes torque work W T and pressure work W F , the energy generated includes the energy E of crushing the waste concrete blocks C and the heat energy E generated by friction T , the functional relationship is shown as follows:

[0033] W T +W F =E C +E T

[0034] Torque work: W T =2πNTt

[0035] Where: N is the speed of the drill bit, T is the torque, and t is the time;

[0036] Work done by pressure: WF =Fvt

[0037] Where: F is pressure, v is drilling speed.

[0038] Assume that the drill has n cutting edges, the radius is r, and the length of the i-th cutting edge is l i (i=1,2,…,n), the force analysis of the drill bit shows that the positive pressure on each cutting edge is:

[0039]

[0040] Friction force on each cutting edge:

[0041]

[0042] Friction Heat energy generated by work:

[0043]

[0044] Where: μ is the friction coefficient between the cutting edge and the waste concrete;

[0045] The above formulas can be solved as follows:

[0046]

[0047] The energy required by the drill to break a unit volume of concrete is:

[0048]

[0049] At the same time, the moisture content α of the waste concrete also has a significant impact on the compressive strength. The uniaxial compressive strength of the waste concrete is established as:

[0050] f c =1.26(1-α)β c +2.11

[0051] The above formula can be used to preliminarily predict the compressive strength of abandoned concrete blocks.

[0052] S3, turn the turntable, and the placement mechanism takes the expansion bolt and installs it in the drilled hole;

[0053] The turntable rotates 120 degrees, and the placement arm of the placement mechanism faces the drilled hole on the waste concrete block and places the expansion bolt;

[0054] When the value of the pressure sensor reaches 1000N, the placement is stopped and the robotic arm applies torque at the same time. When the value of the torque sensor reaches 100N·m, the movement is stopped and the expansion bolt is placed.

[0055] S4. Turn the turntable, and the pull-out mechanism pulls out the expansion bolts in the holes, and records the pull-out pressure;

[0056] The turntable rotates 120 degrees, so that the pull-out mechanism arm faces the expansion bolt and pulls the expansion bolt upward. The pull-out tension sensor records the change of force over time and transmits it to the control system.

[0057] Peak pull-out force F max The relationship between the strength of the waste concrete is:

[0058] f c =2.17F max -5.23

[0059] S5. Repeat the above steps to conduct multiple tests, record no less than five groups of valid data and calculate the average value.

[0060] Preferably, the length×width×height of the waste concrete block is between 100mm×100mm×100mm and 500mm×500mm×500mm.

[0061] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a waste concrete mechanical properties testing device and a testing method, which have the following beneficial effects:

[0062] 1. Based on the relationship between work done and energy conversion during the drilling process of the drill bit, the present invention establishes the relationship between the strength of the waste concrete and the torque, thrust and drilling speed of the drill bit, as well as the relationship between the peak pull-out force and the strength of the waste concrete during the pull-out process of the expansion bolt. The strength of the waste concrete is comprehensively evaluated by the drilling method and the pull-out method, which is more accurate than the existing technology;

[0063] 2. The present invention has a high degree of informatization and has multiple high-precision sensors, which can obtain the changes of load displacement over time in real time; it has strong adaptability and can detect abandoned concrete specimens of different shapes; it can also be used for on-site detection with a short test time. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0065] Figure 1 A formal diagram of the test device provided by the present invention;

[0066] Figure 2A front view of the drilling mechanism, the placing mechanism and the extracting mechanism provided by the present invention;

[0067] Figure 3 A top view of the movable plate provided by the present invention;

[0068] Figure 4 A basic top view provided for the present invention;

[0069] Figure 5 A cross-sectional view of a drill bit provided by the present invention.

[0070] in,

[0071] 1-foundation; 2-guide column; 3-movable plate; 4-turntable; 5-drilling mechanism; 51-first hinge ring; 52-drilling torque sensor; 53-drilling pressure sensor; 54-drilling displacement sensor; 55-drill bit; 551-cutting edge; 6-placing mechanism; 61-second hinge ring; 62-placement of torque sensor; 63-placement of pressure sensor; 64-placement of mechanical arm; 7-pulling mechanism; 71-third hinge ring; 72-pulling tension sensor; 73-pulling mechanical arm; 8-clamp; 9-fixing mechanical arm; 10-pad; 11-motor; 12-control system; 13-abandoned concrete block. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] Embodiment 1:

[0074] See attached Figures 1 to 5 The embodiment of the present invention discloses a waste concrete mechanical property testing device, comprising:

[0075] Foundation 1, a clamp 8 is fixed in the middle of the top surface of the foundation 1 to clamp the waste concrete block 13;

[0076] A plurality of guide posts 2 are vertically fixed in an array on the top surface of the foundation 1;

[0077] A movable plate 3, the panel of which is vertically slidably connected to the plurality of guide pillars 2;

[0078] A turntable 4, the top surface of which is rotatably connected to the bottom surface of the movable plate 3;

[0079] A drilling mechanism 5, the drilling mechanism 5 is fixed to the bottom surface of the turntable 4 to drill holes in the waste concrete blocks 13;

[0080] A placing mechanism 6 is fixed to the bottom surface of the turntable 4 to place expansion bolts into the drilled holes;

[0081] A pull-out mechanism 7, the pull-out mechanism 7 is fixed to the bottom surface of the rotating disk 4 to pull out the expansion bolts;

[0082] The axes of the drilling mechanism 5 , the placing mechanism 6 and the pulling mechanism 7 are arranged in an isosceles triangle on the bottom surface of the rotating disk 4 .

[0083] In this embodiment, the drilling mechanism 5 includes a first connecting rod and a drill bit 55. The first connecting rod is vertically fixed to the bottom surface of the turntable 4. One end of the drill bit 55 is hinged to the end of the first connecting rod away from the turntable 4 through a first hinge ring 51. The outer wall of the drill bit 55 is fixed with a drilling torque sensor 52, a drilling pressure sensor 53 and a drilling displacement sensor 54.

[0084] The placement mechanism 6 includes a second connecting rod and a placement mechanical arm 64. The second connecting rod is vertically fixed to the bottom surface of the turntable 4. One end of the placement mechanical arm 64 is hinged to the end of the second connecting rod away from the turntable 4 through a second hinge ring 61. A placement torque sensor 62 and a placement pressure sensor 63 are fixed on the placement mechanical arm 64.

[0085] The pulling mechanism 7 includes a third connecting rod and a pulling mechanical arm 73. The third connecting rod is vertically fixed to the bottom surface of the turntable 4. One end of the pulling mechanical arm 73 is hinged to the end of the third connecting rod away from the turntable 4 through a third hinge ring 71. A pulling tension sensor 72 is fixed to the pulling mechanical arm 73.

[0086] like Figure 2 and 3 As shown, the drilling mechanism, the placement mechanism and the extraction mechanism are arranged in an isosceles triangle on the bottom surface of the turntable. The drill bit can be bent 90 degrees relative to the first connecting rod through the first hinge ring, the placement mechanical arm can be bent 90 degrees relative to the second connecting rod through the second hinge ring, and the extraction mechanical arm can be bent 90 degrees relative to the third connecting rod through the third hinge ring;

[0087] During the test, first the drill bit coincides with the axis of the first connecting rod, the placing robot arm and the pulling out robot arm are bent 90 degrees so that their axes are perpendicular to the axes of the second connecting rod and the third connecting rod respectively, and the movable plate moves the drill bit downward to drill holes; after the drilling is completed, the movable plate moves up, and at the same time the drill bit is bent 90 degrees to make it perpendicular to the first connecting rod, the placing robot arm is reset so that its axis coincides with the axis of the second connecting rod, the turntable rotates 120 degrees, so that the placing robot arm corresponds to the drilling hole and the movable plate moves down to place the expansion bolt; after the expansion bolt is placed, the movable plate moves up, and at the same time the placing robot arm is bent 90 degrees so that its axis is perpendicular to the axis of the second connecting rod, the pulling out robot arm is reset so that its axis coincides with the axis of the third connecting rod, the turntable rotates 120 degrees so that the pulling out robot arm corresponds to the expansion bolt, and at the same time the movable plate moves down to connect the pulling out robot arm to the lifting ring at the top of the expansion bolt, and the movable plate moves up to pull out the expansion bolt, completing one test.

[0088] In order to further optimize the above technical solution, improve the stability of the discarded concrete blocks during the test and make them firmly fixed on the fixture, a plurality of fixed mechanical arms 9 are fixed on the top surface of the foundation 1 relative to the peripheral side of the fixture 8 to fix the discarded concrete blocks 13.

[0089] In order to further optimize the above technical solution and better realize the up and down sliding of the movable plate along the guide pillars, there are four guide pillars 2 and they are arranged at the four corners of the top surface of the foundation 1. The guide pillar 2 includes a base and a ball screw. The base is fixed on the top surface of the foundation 1, and the ball screw is rotatably connected to the top surface of the base. A threaded sleeve is threadedly connected on the ball screw. The movable plate 3 is provided with an engaging hole on the panel corresponding to the ball screw and is engaged with the threaded sleeve to move up and down along the ball screw with the threaded sleeve. The four ball screws moving synchronously are used to realize the up and down movement of the movable plate.

[0090] In some other specific embodiments, the guide column may also be a slide rail, on which a slider is slidably connected, and the movable plate is embedded in the slider row, and the slider is used to realize the movable plate sliding up and down along the slide rail.

[0091] In order to further optimize the above technical solution and ensure that the turntable can rotate effectively, a motor 11 is fixed to the top surface of the movable plate 3, and the output shaft of the motor 11 passes through the panel of the movable plate 3 and is fixed to the turntable 4 to drive the turntable 4 to rotate.

[0092] In order to further optimize the above technical solution, a pad 10 is embedded between the two opposite end surfaces of the motor 11 and the movable plate 3 .

[0093] In order to further optimize the above technical solution and realize automatic control during the test process, the motor 11 , the drilling mechanism 5 , the placing mechanism 6 , and the pulling mechanism 7 are all communicatively connected to the control system 12 .

[0094] Embodiment 2:

[0095] The embodiment of the present invention discloses a method for testing the mechanical properties of waste concrete, using the performance testing device in embodiment 1 to perform a performance test on waste concrete blocks, specifically comprising the following steps:

[0096] S1, clamping the waste concrete block on the fixture;

[0097] The control system is turned on, the movable plate is adjusted to a suitable height, the waste concrete block is placed in the fixture, and the fixed robotic arm is adjusted to a suitable position to fix the waste concrete block.

[0098] S2, moving the movable plate downward, the drilling mechanism drills holes in the waste concrete blocks, and records the curves of drilling torque and drilling pressure changing with time;

[0099] Operate the control system to move the movable plate downward along the guide column to the surface of the abandoned concrete block. The placement mechanism and the extraction mechanism's placement arm and extraction arm rotate 90 degrees around the second hinge ring and the third hinge ring respectively to avoid contact with the abandoned concrete block during drilling; then the drill bit of the drilling device starts working, and after adjusting the drilling speed, the movable plate moves downward, and the drill bit starts drilling. The drilling torque sensor and the drilling pressure sensor record the curves of torque and pressure changes over time and upload them to the control system. When the displacement value recorded by the drilling displacement sensor reaches 30mm, the drill bit stops working, the movable plate moves upward along the guide column to a suitable position, and the drilling work is completed;

[0100] In this embodiment, according to the principle of energy conservation, a relationship model between the work done by the drill bit during drilling and energy conversion is established. The work done by the drill bit during drilling includes torque work W T and pressure work W F , the energy generated includes the energy E of crushing the waste concrete blocks C and the heat energy E generated by friction T , the functional relationship is shown in formula (1):

[0101] W T +W F =E C +E T (1)

[0102] Torque work W T It can be expressed as formula (2):

[0103] W T =2πNTt (2)

[0104] Where: N is the speed of the drill bit, T is the torque, and t is the time;

[0105] Pressure work W F It can be expressed as formula (3):

[0106] W F =Fvt (3)

[0107] Where: F is pressure, v is drilling speed.

[0108] like Figure 5 As shown, it is assumed that the drill bit 55 has n cutting edges 551, the radius is r, and the length of the i-th cutting edge is l i (i=1,2,…,n), the force analysis of the drill bit shows that the positive pressure on each cutting edge It can be expressed as formula (4):

[0109]

[0110] Friction force on each cutting edge It can be expressed as formula (5):

[0111]

[0112] Friction Heat energy E generated by work T It can be expressed as formula (6):

[0113]

[0114] Where: μ is the friction coefficient between the cutting edge and the waste concrete;

[0115] From formulas (2), (3), and (6), we can get E C , as shown in formula (7):

[0116]

[0117] Energy required by the drill to break a unit volume of concrete β C It can be expressed as formula (8):

[0118]

[0119] At the same time, the moisture content of waste concrete α also has a significant impact on the compressive strength. The uniaxial compressive strength of waste concrete f c , which can be expressed as formula (9):

[0120] f c =1.26(1-α)β c +2.11 (9)

[0121] The compressive strength of the abandoned concrete blocks can be preliminarily predicted by formula (9).

[0122] S3, turn the turntable, and the placement mechanism takes the expansion bolt and installs it in the drilled hole;

[0123] The placement robot arm is reset, and the drill bit rotates 90 degrees around the first hinge ring. The motor starts and controls its output shaft to rotate 120 degrees, so that the placement robot arm is aligned with the drill hole, and the movable plate moves downward. When the value recorded by the placement pressure sensor reaches 1000N, it stops moving. At the same time, the placement robot arm applies torque to the expansion bolt. When the torque reaches 100N·m, the robot arm stops moving, and the movable plate moves upward along the guide column to the appropriate position, and the expansion bolt placement work is completed. ;

[0124] S4. Turn the turntable, and the pull-out mechanism pulls out the expansion bolts in the holes, and records the pull-out pressure;

[0125] The pull-out robot arm is reset, the placement robot arm is rotated 90 degrees around the second hinge ring, the motor output shaft is rotated 120 degrees, the pull-out robot arm is aligned with the expansion bolt, and the movable plate moves downward along the guide column until the pull-out robot arm is connected to the circular ring at the top of the expansion bolt; the movable plate moves upward, and the pull-out tension sensor records the change of force over time and transmits it to the control system.

[0126] Peak pull-out force F max The relationship between the strength of the waste concrete is shown in formula (10):

[0127] f c =2.17F max -5.23 (10)

[0128] S5. Repeat the above steps to conduct multiple tests, record no less than five groups of valid data and calculate the average value.

[0129] The movable plate was reset, the position of the discarded concrete block was adjusted, and the test was repeated at least five times. The results are shown in the following table:

[0130] Test results of mechanical properties of waste concrete

[0131] Number of trials 1 2 3 4 5 Drilling (MPa) 42.3 43.1 44.5 40.5 43.8 Pull out (MPa) 41.7 43.6 42.9 41.9 42.4 Average value (MPa) 42.0 43.4 43.7 41.2 43.1

[0132] In order to further optimize the above technical solution, the length×width×height of the waste concrete block 13 is between 100mm×100mm×100mm and 500mm×500mm×500mm.

[0133] In this embodiment, the length range of the drill bit in step S2 is 40 mm to 60 mm; the diameter of the drill bit is 8 mm to 16 mm; the rotation speed is 500 r / min to 1000 r / min; the accuracy of the drilling torque sensor, drilling pressure sensor and drilling displacement sensor are 0.1 N·m, 0.1 N and 0.1 mm respectively.

[0134] In order to further optimize the above technical solution, in step S3, the length of the expansion bolt is 20 mm to 30 mm; the range of the pressure that can be applied is 0 to 2000 N; and the range of the torque that can be applied is 0 to 200 N·m.

[0135] In order to further optimize the above technical solution, the pulling force applied in step S4 should be continuous and uniform, the speed should be controlled between 0.2 kN / s and 0.5 kN / s, and the accuracy of the tension sensor should be 0.1N.

[0136] In order to further optimize the above technical solution, the strength difference between drilling in and pulling out in step S5 should be within 10%, otherwise it is invalid data, and each waste concrete test block should have at least 5 valid data. The average value of the valid data is taken as the strength value of the waste concrete.

[0137] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0138] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waste concrete mechanical properties testing device, characterized in that: include: A foundation (1), wherein a clamp (8) is fixed at the middle of the top surface of the foundation (1) to clamp the waste concrete block (13); Guide pillars (2), the guide pillars (2) being multiple and arranged in an array and vertically fixed on the circumference of the top surface of the foundation (1); A movable plate (3), the panel of which is vertically slidably connected to the plurality of guide pillars (2); A rotating disk (4), the top surface of which is rotatably connected to the bottom surface of the movable plate (3); A drilling mechanism (5), wherein the drilling mechanism (5) is fixed to the bottom surface of the rotating disk (4) to drill holes in the waste concrete blocks (13); A placing mechanism (6), wherein the placing mechanism (6) is fixed to the bottom surface of the turntable (4) to place expansion bolts into the drilled holes; A pulling-out mechanism (7), wherein the pulling-out mechanism (7) is fixed to the bottom surface of the rotating disk (4) for pulling out the expansion bolt; The axes of the drilling mechanism (5), the placing mechanism (6) and the pulling mechanism (7) are arranged in an isosceles triangle on the bottom surface of the rotating disk (4).

2. A waste concrete mechanical properties testing device according to claim 1, characterized in that: The drilling mechanism (5) comprises a first connecting rod and a drill bit (55); the first connecting rod is vertically fixed to the bottom surface of the turntable (4); one end of the drill bit (55) is hinged to an end of the first connecting rod away from the turntable (4) through a first hinge ring (51); and a drilling torque sensor (52), a drilling pressure sensor (53) and a drilling displacement sensor (54) are fixed to the outer wall of the drill bit (55).

3. A waste concrete mechanical properties testing device according to claim 2, characterized in that: The placement mechanism (6) comprises a second connecting rod and a placement mechanical arm (64), wherein the second connecting rod is vertically fixed to the bottom surface of the turntable (4), one end of the placement mechanical arm (64) is hinged to an end of the second connecting rod away from the turntable (4) through a second hinge ring (61), and a placement torque sensor (62) and a placement pressure sensor (63) are fixed to the placement mechanical arm (64).

4. A waste concrete mechanical properties testing device according to claim 3, characterized in that: The pulling mechanism (7) comprises a third connecting rod and a pulling mechanical arm (73), wherein the third connecting rod is vertically fixed to the bottom surface of the rotating disk (4), one end of the pulling mechanical arm (73) is hinged to an end of the third connecting rod away from the rotating disk (4) through a third hinge ring (71), and a pulling tension sensor (72) is fixed to the pulling mechanical arm (73).

5. The waste concrete mechanical properties testing device according to claim 1, characterized in that: A plurality of fixing mechanical arms (9) are fixed to the top surface of the foundation (1) on the peripheral side of the clamp (8) to fix the waste concrete blocks (13).

6. The waste concrete mechanical properties testing device according to claim 1, characterized in that: There are four guide pillars (2) arranged at the four corners of the top surface of the base (1). The guide pillars (2) include a base and a ball screw. The base is fixed to the top surface of the base (1). The ball screw is rotatably connected to the top surface of the base. A threaded sleeve is threadedly connected to the ball screw. The movable plate (3) is provided with an engaging hole on the panel corresponding to the ball screw and is engaged with the threaded sleeve so as to move up and down along the ball screw with the threaded sleeve.

7. The waste concrete mechanical properties testing device according to claim 1, characterized in that: A motor (11) is fixed to the top surface of the movable plate (3); an output shaft of the motor (11) passes through the panel of the movable plate (3) and is fixed to the turntable (4) to drive the turntable (4) to rotate.

8. The waste concrete mechanical properties testing device according to claim 7, characterized in that: The motor (11), the drilling mechanism (5), the placing mechanism (6), and the pulling mechanism (7) are all communicatively connected to a control system (12).

9. A method for testing the mechanical properties of waste concrete, characterized in that: The waste concrete mechanical properties testing device according to any one of claims 1 to 8 is used to perform a performance test on waste concrete blocks, specifically comprising the following steps: S1, clamping the waste concrete block on the fixture; S2, moving the movable plate downward, the drilling mechanism drills holes in the waste concrete blocks, and records the curves of drilling torque and drilling pressure changing with time; S3, turn the turntable, and the placement mechanism takes the expansion bolt and installs it in the drilled hole; S4. Turn the turntable, and the pull-out mechanism pulls out the expansion bolts in the holes, and records the pull-out pressure; S5. Repeat the above steps to conduct multiple tests, record no less than five groups of valid data and calculate the average value.

10. A method for testing mechanical properties of waste concrete according to claim 9, characterized in that: The length×width×height of the waste concrete block (13) is between 100mm×100mm×100mm and 500mm×500mm×500mm.

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