WO2021129184A1

WO2021129184A1 - Manufactured sand water absorption rate measuring device and method

Info

Publication number: WO2021129184A1
Application number: PCT/CN2020/126762
Authority: WO
Inventors: 王旭昊; 甘珑; 李程; 司伟; 余海洋; 刘泽鑫; 余祥晶; 宋鹏飞; 赵小春
Original assignee: 长安大学
Priority date: 2019-12-28
Filing date: 2020-11-05
Publication date: 2021-07-01
Also published as: AU2020413969A1; CN110926902A

Abstract

A manufactured sand water absorption rate measuring device and method. A drying device (18), a tamping device, and a slump cone sample mold (17) are provided in a box (2). Manufactured sand is dried by means of stirring and by heating a boiler body (23), thereby improving drying efficiency, also solving the problem of reduced stone powder content of manufactured sand in an existing air-drying process, and effectively ensuring the measurement accuracy of the water absorption rate of the manufactured sand. Next, an opening is formed in the bottom of the boiler body (23), so that dried manufactured sand automatically flows into the slump cone sample mold (17), and the dried manufactured sand is tamped by using the tamping device, thereby avoiding the process of manually filling the manufactured sand, and improving the measurement efficiency. Finally, tamping is performed by the tamping device, thereby reducing the labor intensity of an operator.

Description

Device and method for measuring water absorption of machine-made sand

Technical field

The invention relates to the technical field of methods for determining the properties of cement concrete fine aggregates, in particular to a device and a method for measuring water absorption of machine-made sand.

Background technique

Fine aggregate is an important part of cement concrete. Among them, fine aggregate includes natural sand and machine-made sand. At present, due to the lack of river sand, machine-made sand has been widely used in cement concrete. The water absorption rate of machine-made sand is one of the important physical properties of machine-made sand. The water absorption rate of machine-made sand affects the water demand and water-cement ratio in the mix ratio of cement concrete, which in turn affects the construction and workability of cement concrete. It also affects the difficulty of construction and the strength and durability of cement concrete in the later stage. At present, the water absorption rate of machine-made sand is measured by the T0330-2005 method in the "Highway Process Aggregate Test Regulations" (JTGE42-2005). This method can simultaneously determine the water absorption of natural sand and machine-made sand. The wet machine-made sand is dried to reach the saturated surface dry state, and then the mold is installed and tamped to determine its water absorption rate.

However, the current use of this method to measure the water absorption of manufactured sand has many disadvantages. First of all, compared with natural sand, machine-made sand has a higher stone powder content and is difficult to stand still. When dumping the water in the machine-made sand container, it is difficult to pour the water to ensure that the stone powder does not lose, resulting in excessive moisture in the sample to be air-dried. The drying time of the blower is too long, which affects the test efficiency; secondly, the machine-made sand and stone powder content is high, and the fine powder is easily lost when air-dried, which affects the test accuracy; further, the free fall of the ramming rod needs to be strictly controlled in real time. The sample does not exceed 10mm, but it is difficult to guarantee this test requirement during manual testing, which reduces the test accuracy; finally, this method requires manual drying and manual loading of the machine-made sand sample into the mold, which is cumbersome and not convenient enough.

CN201620478495.3 provides a device for measuring dry water absorption rate of machine-made sand saturated surface. This method is based on the T0330-2005 method in the "Highway Process Aggregate Test Regulations" (JTG E42-2005), under the machine-made sand container pan A heating mechanism is provided to replace the hair dryer for air drying, but the efficiency of this method is still too low and the heating is uneven during drying. There are also problems such as insufficient test accuracy and cumbersome operation.

Therefore, there is an urgent need for a high-efficiency, high-precision, and convenient water absorption rate measuring device for machine-made sand for experimental research and engineering applications.

Summary of the invention

Aiming at the problem of low accuracy in measuring the water absorption rate of the existing manufactured sand, the present invention provides a device and method for measuring the water absorption rate of manufactured sand, so as to realize accurate and efficient measurement of the water absorption rate of manufactured sand.

The present invention is realized through the following technical solutions:

A device for measuring water absorption of machine-made sand, comprising a box body in which a slump cylinder test model is arranged, and the top of the slump cylinder test model is provided with a drying device and a tamping device;

The drying module includes a stirring device, a pot body and a heating device;

The pot body is suspended in the box body, the upper part of the stirring device is fixed on the box body, the lower part of the stirring device extends into the pot body, and the pot body is provided with a heating device for drying the machine-made sand. An outlet is provided at the bottom of the slump to pour the dried machine-made sand into the slump cylinder test mold, and the tamping device is used to tamping the machine-made sand in the slump cylinder test mold.

Preferably, the stirring device includes an electric rotor, a stirring blade and a stirring shaft;

The top of the electric rotor is connected with the top of the box body, the stirring shaft is connected with the rotating shaft of the electric rotor, the stirring blade is arranged on the stirring shaft, and the stirring blade extends into the pot body.

Preferably, the side wall of the pot body has a hollow sandwich structure, and the heating device is arranged in the sandwich.

Preferably, a funnel is provided at the center of the bottom of the pot body, and the dried machine-made sand enters the slump cylinder test mold through the funnel.

Preferably, the tamping device includes a fixed pulley, a steel wire rope, a tamping rod and a motor;

The fixed pulley is fixed on the top of the box body, one end of the steel wire rope is connected with the output shaft of the motor, the motor is located outside the box body, and the other end of the wire rope bypasses the fixed pulley and is connected to the top of the ram.

Preferably, the box is also provided with a laser rangefinder for measuring the distance from the bottom of the ram to the surface of the machine-made sand sample in the slump cylinder test mold.

Preferably, a steel wire rope pipe is further provided on the inner wall of the box, and the end of the steel wire rope passes through the steel wire rope pipe and bypasses the fixed pulley to be connected to the ram.

Preferably, the bottom of the box body is also provided with a transmission belt, and the slump cylinder test mold is placed on the transmission belt, and the transmission belt is used to move the slump cylinder test mold to the bottom of the drying device or the tamping device.

Preferably, the test mold of the slump cylinder is placed on the transmission belt through a machine-made sand tray.

The present invention also provides a measuring method of the above-mentioned machine-made sand water absorption rate measuring device, which includes the following steps:

Step 1. Pour the wet machine-made sand into the pot;

Step 2. Start the stirring device and the heating device to dry the machine-made sand in the pot;

Step 3. Pour the machine-made sand obtained in step 2 into the slump cylinder test mold;

Step 4. Use a tamping device to tamping the machine-made sand in the slump cylinder test mold;

Step 5. Perform a slump test on the tamped machine-made sand to determine whether the machine-made sand reaches a saturated surface dry state;

When the machine-made sand reaches the saturated surface dry state, go to step 6, otherwise go to step 2;

Step 6. The sand water absorption rate is measured for the machine-made sand that has reached the saturated surface dry state.

Compared with the prior art, the present invention has the following beneficial technical effects:

The invention provides a device for measuring water absorption of machine-made sand. A drying device, a tamping device and a slump cylinder test model are arranged in a box. The machine-made sand is dried by means of stirring and heating the pot, which greatly improves The drying efficiency is improved, and at the same time, the problem of the reduction of the stone powder content in the machine-made sand caused by the air-drying process of the existing hair dryer is solved. Therefore, the measurement accuracy of the water absorption rate of the machine-made sand can be effectively guaranteed. Secondly, through the opening at the bottom of the pot body, The dried machine-made sand is automatically flowed into the slump cylinder test mold, and the dried machine-made sand is tamped by the tamping device, which avoids the process of manual filling of the machine-made sand, improves the measurement efficiency, and finally passes through the automatic tamping device Tamping reduces the error of manual tamping and improves the measurement accuracy.

Furthermore, the electric rotor drives the mixing blade to stir the machine-made sand, which improves the drying efficiency of the machine-made sand and at the same time enables the machine-made sand to be evenly heated.

Further, the heating device is arranged in the interlayer of the pot body to ensure that the pot body is evenly heated, and at the same time, the safety during drying is improved.

Further, the motor is used to control the tamping rod through the steel wire rope to perform automatic tamping, and the structure is simple, which reduces the operation error of the tester and improves the measurement accuracy.

Further, the distance between the bottom surface of the tamping rod and the surface of the machine-made sand sample in the slump cylinder test mold is measured by a laser rangefinder to ensure that the tamping process meets the requirements of the regulations and improve the measurement accuracy.

Furthermore, the movement of the machine-made sand tray equipped with the slump cylinder test mold is controlled by the transmission belt to further improve the measurement efficiency.

The present invention also provides the measurement method of the above-mentioned measuring device. Firstly, the heating of the machine-made sand is realized by the drying device, and the real-time stirring is realized by stirring at the same time, so that the machine-made sand is heated evenly, and the setting of the drying module ensures that the machine-made sand is quickly and evenly dried. Dry to the saturated surface dry state, and at the same time eliminate the loss of fine powder, which affects the test accuracy; secondly, the machine-made sand is dried to the saturated surface dry state and then automatically loaded into the slump cylinder test mold, which is compared with the traditional manual method. Dumping the mold, the process realizes the automatic and rapid filling of the machine-made sand to the slump cylinder test mold, which improves the test efficiency; then, the ramming rod is combined with the laser rangefinder to automatically tamping in accordance with the tamping requirements specified in the specification. This process uses a ramming rod. The automatic tamping eliminates the manual tamping error in the existing methods and improves the test accuracy. Finally, operate according to the T0330-2005 regulation in the "Highway Process Aggregate Test Regulations" and measure the water absorption rate of machine-made sand.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the measuring device of the present invention;

Figure 2 is a schematic diagram of the structure of the drying module of the present invention.

Among them, 1. Power supply; 2. Box; 3. Base; 4. Conveyor belt; 5. Control unit; 6. Motor; 7. Laser rangefinder; 8. Fixed pulley; 9. Steel wire rope; 10. Tamping rod; 11. , Wire rope pipeline; 12. The first button; 14, the second button; 15, the entrance and exit; 16, the machine-made sand tray; 17, the slump cylinder test model; 18. Drying device; 19. Electric rotor fixed block; 20, Electric rotor; 21. Mixing blade; 22. Mixing shaft; 23. Pot body; 24. Electric heating wire; 25. Funnel; 26. Funnel switch; 27. Control system; 28.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings, which is an explanation but not a limitation of the present invention.

1 and 2, a device for measuring water absorption of machine-made sand includes a box body 2, a control system 27, and a drying device 18, a slump cylinder test mold 17 and a tamping device arranged in the box body 2.

Among them, the front of the box 2 is provided with a fetching port, the drying device 18 is located at the top of the box 2, and the slump cylinder test mold 17 is set at the bottom of the box 2, and is located directly below the drying device 18. The device is set on the top of the box body and is used for tamping the machine-made sand in the slump cylinder test mold 17.

The drying module 18 includes an electric rotor fixing block 19, an electric rotor 20, a stirring blade 21, a stirring shaft 22, a pot body 23, an electric heating wire 24, a hopper 25 and a hopper switch 26.

Wherein, the upper end of the electric rotor 20 is fixed to the top of the box body 2 by the electric rotor fixing block 19, the control end of the electric rotor 20 is connected with the output end of the control system 27, the upper end of the stirring shaft 22 is connected with the lower end of the electric rotor 20, The electric rotor 20 drives the stirring shaft 22 to rotate, the stirring blade 21 is fixed on the stirring shaft 22, the stirring blade 21 is located in the pot body 23, the pot body 23 is set in the box body 2 through the pot body clamping groove 28, and the pot body clamping groove 28 is fixed On the inner wall of the box body 2, the side wall of the pot body 23 is provided with an electric heating wire 24 that can be energized and heated. The center of the bottom of the pot body 23 is provided with a discharge port. The lower part of the pot body 23 is also provided with a funnel 25, which can interact with the discharge The port is connected, and a funnel switch 26 is provided on the upper part of the funnel 25.

The funnel switch 26 is a plug-in board, and a horizontal slot is provided at the connection between the pot body 23 and the funnel. The plug-in board is fitted in the slot, and the plug-in board can move horizontally in the slot, so that the bottom of the pot body 23 can be moved horizontally. The discharge port is closed or opened.

The stirring blade 21 is spirally arranged on the stirring shaft 22 for stirring the machine-made sand of the pot body.

The pot body clamping groove is used to constrain the pot body 23 to ensure the stability of the pot body. The pot body 23 is detachable and is arranged in the pot body clamping groove 28.

The side wall of the pot body 23 has a hollow sandwich structure, and the electric heating wires 24 are evenly distributed in the interlayer, and the machine-made sand in the pot body 23 is dried by uniform heating of the electric heating wires.

The slump cylinder test mold 17 has a conical structure and has an open structure at both ends. The slump cylinder test mold 17 is placed in the machine-made sand tray 16, and the machine-made sand tray 16 is placed at the bottom of the box body 2, and The entrance of the slump cylinder test mold 17 is directly opposite to the outlet of the funnel 25, to ensure that the dried machine-made sand falls into the slump cylinder test mold 17, and the machine-made sand tray 16 is used to receive from the slump cylinder test mold 17 and The machine-made sand spilled during the tamping process can avoid waste of machine-made sand and environmental pollution.

The bottom of the box 2 is provided with a base 3, and a conveyor belt 4 is provided on the base 3, which is used to transport the slump cylinder test mold 17 filled with machine-made sand to the tamping position, that is, directly under the tamping device, the machine-made sand tray 16 is located on the conveyor belt 4, the slump cylinder test mold 17 is placed on the machine-made sand tray 16, and the center of the slump cylinder test mold 17 is aligned with the center of the funnel 25.

The tamping device includes a fixed pulley 8, a steel wire rope 9, a laser rangefinder 7, a tamping rod 10 and a motor 6.

The fixed pulley 8 is fixed on the top of the box body 2. One end of the wire rope 9 is connected to the output shaft of the motor 6. The motor is located on the outside of the box body. The other end of the wire rope 9 bypasses the fixed pulley 8 and is connected to the top of the ram 10. The control terminal of 6 is connected to the output terminal of the control system 27.

The front of the box body 2 is provided with a box body entrance 15, and the inner wall of the box body 2 is also provided with a wire rope pipe 11, the wire rope 9 passes through the wire rope pipe 11 and then bypasses the fixed pulley 8 and is connected to the ram 10.

The laser rangefinder 7 is set on the top of the box 2 to detect the distance between the bottom surface of the ram 10 and the surface of the machine-made sand sample in the slump cylinder test mold 17, the output end of the laser rangefinder 7 and the control system 27 Connected to the input terminals.

The control system 27 includes a first button 12, a second button 14, a control unit 5, and a power source 1 for providing electric energy. The control unit 5 is connected to the first button 12, the second button 14, the electric rotor 20, the heating wire 24, The conveyor belt 4, the motor 6 and the laser rangefinder 7 are connected.

The first button 12 is used to control the working state of the heating wire 24 and the electric rotor 20; the second button 14 is used to control the working state of the conveyor belt.

The measuring method of a device for measuring water absorption of machine-made sand provided by the present invention is described in detail below, including the following steps:

1) Open the entrance and exit 15, and pour the wet machine-made sand that has been poured with excess water, which has been made according to the T0330-2005 method in the "Highway Process Aggregate Test Regulations", into the pot body 23.

2) Turn on the power supply 1, click the first button 12, the heating wire 24 in the pot body 23 starts to heat, and the electric rotor 20 drives the stirring blade 21 to stir the machine-made sand. At the same time, the technician observes the wet state of the machine-made sand sample and makes a preliminary judgment. Whether it has reached the saturated surface dry state.

3) When it is judged that the machine-made sand reaches the saturated surface dry state, click the first button 12, the heating wire 24 and the electric rotor 20 stop working, move the insert plate to open the outlet of the pot body, and the machine-made sand after drying passes through the funnel 25 flows to the slump cylinder test mold 17, when the machine-made sand is filled with the slump cylinder test mold 17, the funnel switch 26 is turned off.

4) Click the second button 14, the conveyor belt 4 will automatically move the machine-made sand tray 16 with the slump cylinder test mold 17 to the center of the ram 10 until the center of the slump cylinder test mold 17 is below the center of the ram 10 , The laser rangefinder 7 measures the distance between the bottom surface of the tamping rod 10 and the sample, so that the distance is less than 10mm. This distance can be achieved by adjusting the length of the wire rope 9; finally, the motor 6 is started to make the tamping rod 10 free fall to ram the machine-made sand real.

The combination of the tamping rod 10 and the laser rangefinder 7 realizes the high-precision tamping of the free-falling body with the end surface of the tamping rod 10 not more than 10mm away from the sample, which meets the requirements of the T0330-2005 method in the "Highway Process Aggregate Test Regulations".

5) Take out the machine-made sand tray 16 with the slump cylinder test mold 17 through the entrance and exit, and operate according to the T0330-2005 method in the "Highway Process Aggregate Test Regulations" to determine whether the machine-made sand sample has reached the saturated surface dry state.

6) If the machine-made sand reaches the saturated surface dry state, the water absorption rate of the machine-made sand shall be measured according to the T0330-2005 method in the "Highway Process Aggregate Test Regulations". If it has not reached the saturated surface dry state, pour the machine-made sand in the slump cylinder test mold 17 and the machine-made sand tray 16 into the pot body 23, and repeat steps 2 to 5 until the saturated surface dry state is reached.

When the device for measuring water absorption of machine-made sand according to the present invention is used, firstly, the heating wire of the drying module is used to heat the machine-made sand, and at the same time, the electric rotor drives the stirring blade to realize real-time stirring, so that the machine-made sand is evenly heated and dried. The setting of the module ensures that the machine-made sand is quickly and evenly dried to the saturated surface dry state, and at the same time, it eliminates the loss of fine powder that affects the test accuracy.

Secondly, after the machine-made sand is dried to the saturated surface dry state, the funnel is automatically loaded into the slump cylinder test mold. Compared with the traditional manual dumping and mold assembly, this process realizes the machine-made sand automatic and fast filling of the slump cylinder test mold, which improves The test efficiency;

Then, the machine-made sand tray on which the slump cylinder test mold is placed is moved by the conveyor belt to the center of the ram bar until the center of the slump cylinder test mold is below the center of the ram bar, combined with the laser range finder to automatically follow the specifications. Tamping is required in practice. This process uses a tamping rod to automatically tamping in real time to eliminate the manual tamping error in the existing method and improve the test accuracy.

The above content is only to illustrate the technical ideas of the present invention, and cannot be used to limit the scope of protection of the present invention. Any changes made on the basis of the technical solutions based on the technical ideas proposed by the present invention fall into the claims of the present invention. Within the scope of protection.

Claims

A device for measuring water absorption of machine-made sand, which is characterized by comprising a box body (2) in which a slump cylinder test mold (17) is arranged, and the top of the slump cylinder test mold (17) is provided with a drying device (18) And tamping device;

The drying module (18) includes a stirring device, a pot body (23) and a heating device;

The pot body (23) is suspended in the box body, the upper part of the stirring device is fixed on the box body, and the lower part of the stirring device extends into the pot body (23). The pot body (23) is provided with a heating device for For drying the machine-made sand, an outlet is provided at the bottom of the pot body (23), which is used to pour the dried machine-made sand into the slump cylinder test mold (17), and the tamping device is used to test the slump cylinder mold (17). 17) The machine-made sand is tamped.
A device for measuring water absorption of machine-made sand according to claim 1, wherein the stirring device comprises an electric rotor (20), a stirring blade (21) and a stirring shaft (22);

The top of the electric rotor (20) is connected with the top of the box body, the stirring shaft (22) is connected with the rotating shaft of the electric rotor, the stirring blade (21) is arranged on the stirring shaft (22), and the stirring blade extends into the pot Body (23).
A device for measuring water absorption of machine-made sand according to claim 1, characterized in that the side wall of the pot body (23) is a hollow sandwich structure, and the heating device is arranged in the sandwich.
The device for measuring water absorption of machine-made sand according to claim 1, characterized in that a funnel is arranged at the center of the bottom of the pot body, and the machine-made sand after drying enters the slump cylinder test mold (17) through the funnel.
A device for measuring water absorption of machine-made sand according to claim 1, characterized in that the tamping device comprises a fixed pulley (8), a steel wire rope (9), a ramming rod (10) and a motor (6);

The fixed pulley (8) is fixed on the top of the box (2), one end of the wire rope (9) is connected with the output shaft of the motor (6), the motor is located on the outside of the box, and the other end of the wire rope (9) goes around The fixed pulley (8) is connected with the top of the ram (10).
A device for measuring water absorption of machine-made sand according to claim 5, characterized in that a laser rangefinder (7) is also provided in the box body for measuring the bottom of the ram (10) to the slump cylinder test The distance between the surface of the machine-made sand sample in the mold (17).
A device for measuring water absorption of machine-made sand according to claim 5, characterized in that a steel wire rope pipe (11) is further provided on the inner wall of the box body (2), and the end of the steel wire rope (9) passes through the wire rope pipe ( 11) And bypass the fixed pulley (8) and connect with the ram (10).
A device for measuring water absorption of machine-made sand according to claim 1, wherein the bottom of the box (2) is also provided with a transmission belt (4), and the slump cylinder test model (17) is placed on the transmission belt. (4) It is used to move the slump cylinder test mold (17) to the bottom of the drying device (18) or the tamping device.
The device for measuring water absorption of machine-made sand according to claim 8, characterized in that the slump cylinder test mold (17) is placed on the transmission belt through a machine-made sand tray (16).
A method for measuring the water absorption rate of machine-made sand according to any one of claims 1-9, characterized in that it comprises the following steps:

Step 1. Pour the damp machine-made sand into the pot body (23);

Step 2. Start the stirring device and the heating device to dry the machine-made sand in the pot body (23);

Step 3. Pour the machine-made sand obtained in step 2 into the slump cylinder test mold (17);

Step 4. Use a tamping device to tamping the machine-made sand in the slump cylinder test mold (17);

Step 5. Perform a slump test on the tamped machine-made sand to determine whether the machine-made sand reaches a saturated surface dry state;

When the machine-made sand reaches the saturated surface dry state, go to step 6, otherwise go to step 2;

Step 6. The sand water absorption rate is measured for the machine-made sand that has reached the saturated surface dry state.