A cement concrete permeability coefficient test instrument

Abstract

The invention discloses a cement concrete permeability coefficient tester, comprising a frame, a water permeability coefficient test device and an air permeability coefficient test device arranged on the frame; the water permeability coefficient test device comprises a water permeability sample cylinder, an overflow water tank and a water collecting measuring cylinder, and the air permeability coefficient test device comprises a vacuum pump, an air compressor, a pressure chamber, an organic glass cylinder, a glass tube and a full-scale recorder installed on the frame. The tester can integrate the water permeability coefficient and the air permeability coefficient of cement concrete samples through the arrangement of the water permeability coefficient test device and the air permeability coefficient test device, and has various functions and is convenient to use; at the same time, through the air bag membrane and the saturation treatment of the sample before the experiment, air leakage is effectively avoided and the experimental accuracy is guaranteed, and the tester has the characteristics of simple structure, convenient use and high accuracy of experimental results.

Description

Technical Field

[0001] The present invention relates to the technical field of civil material testing equipment, and in particular to a cement concrete permeability coefficient testing instrument. Background Art

[0002] With the development of current construction technology and industrial technology, cement concrete has become an indispensable building material for human beings. At present, the concrete on the market includes two types of cement concrete materials, plastic concrete and permeable concrete, according to its permeability characteristics. Among them, plastic concrete refers to the concrete with a compressive strength range of 1-5MPa, an elastic modulus of 300-2000MPa, and a permeability coefficient of n×10 -6 ~n×10 -8 Concrete material with high fluidity and underwater concrete, mostly used in the anti-seepage wall structure of earth-rock dam; Permeable concrete is also called porous concrete, permeable floor, which is a porous lightweight concrete made of aggregate, cement and water. It does not contain fine aggregate, and the surface of coarse aggregate is covered with a thin layer of cement slurry to bond with each other to form a honeycomb structure with uniformly distributed holes. Therefore, it has the characteristics of air permeability, water permeability and light weight. It can also be called sandless concrete. It is mainly used for the pouring of some permeable pavements and buildings with hard permeability requirements;

[0003] Therefore, with the practice of a large number of concrete mix design and construction sampling inspection, it is reflected to varying degrees that plastic concrete has the problem of mismatching design indicators. Due to the low strength, the test of concrete impermeability cannot be carried out according to the specified requirements, which has caused certain difficulties in the assessment of concrete engineering quality. This is mainly due to the problems of existing permeability coefficient test methods and equipment; for example, when the equipment is measuring the permeability coefficient of concrete samples, it is directly measured on the measuring equipment, while ignoring the influence of pores in the concrete samples on the experimental results; at the same time, the permeability coefficient test equipment currently used in the market can only realize a single water seepage or air seepage experiment when conducting the permeability coefficient test of cement concrete, resulting in cumbersome operation and inconvenient use; and most of the current permeability coefficient test methods have the problem of side wall leakage, which makes it impossible to effectively guarantee the test accuracy;

[0004] Therefore, it is urgent to design a cement concrete permeability coefficient experimental device that can achieve multifunctional measurement to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention aims to provide a cement concrete permeability coefficient tester. The tester is equipped with a water permeability coefficient test device and an air permeability coefficient test device, so that the device can integrate the measurement of the water permeability coefficient and the air permeability coefficient of cement concrete samples. The device has various functions and is easy to use. At the same time, the air bag membrane and the saturation treatment of the sample before the experiment are used to effectively avoid air leakage and ensure the experimental accuracy. The device has the characteristics of simple structure, easy use and high accuracy of experimental results.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A cement concrete permeability coefficient tester comprises a frame, a water permeability coefficient test device and an air permeability coefficient test device arranged on the frame;

[0008] The water permeability coefficient test device comprises a water permeable sample cylinder, an overflow water tank and a water collecting graduated cylinder. The water permeable sample cylinder is arranged in the overflow water tank through a height adjustment mechanism, connected to a water source through a water inlet pipe, and a cement concrete sample is arranged at the lower end of the water permeable sample cylinder; the overflow water tank is fixedly mounted on a frame, and a second overflow port is arranged at the upper end of the overflow water tank, and the water collecting graduated cylinder is arranged at the lower side of the second overflow port and is used in conjunction with the second overflow port;

[0009] The air permeability coefficient experimental device includes a vacuum pump, an air compressor, a pressure chamber, a plexiglass cylinder, a glass tube and a full-scale recorder installed on a frame. The pressure chamber is arranged on the operating table of the vacuum pump, and includes, from top to bottom, a first compression chamber, a second compression chamber and a third compression chamber that are interconnected. The first compression chamber, the second compression chamber and the third compression chamber are all provided with pressure sensors, and the pressure sensors are connected to the full-scale recorder through connecting wires. A sample is installed in the second compression chamber; the air compressor is connected to the second compression chamber through an air pipe; the air inlet of the glass cylinder is connected to the air compressor, and the air outlet is connected to the third compression chamber through an air pipe; the air extraction hole of the first compression chamber is connected to the vacuum pump and the glass tube respectively through air pipes.

[0010] Preferably, the water permeable sample tube comprises an upper tube body and a lower tube body which are detachably connected.

[0011] The upper cylinder is arranged at the upper end of the lower cylinder, and a first overflow port is arranged on the upper cylinder, the water inlet pipe is arranged at the water inlet at the upper end of the upper cylinder, and a control valve is arranged on the water inlet pipe;

[0012] The lower cylinder is arranged at the lower end of the upper cylinder through a connecting column, the sample is fixed in the lower cylinder through a sample sleeve, the height adjustment mechanism is arranged on the lower cylinder, and a leakage hole is also arranged on the bottom plate of the lower cylinder;

[0013] The connecting column is a sleeve structure, and a pressure plate is arranged at the upper end of the connecting column, and the pressure plate is used in conjunction with the open groove on the upper cylinder. The connecting column is also provided with external threads for use in conjunction with the first fastening nut and the second fastening nut respectively.

[0014] Preferably, the height adjustment mechanism comprises a linkage adjustment component and a manual leveling component that cooperate with each other, and the linkage adjustment component comprises a rotating fixing member, a top column, an adjustment button and a synchronous belt.

[0015] The rotating fixing member is rotatably installed in the open groove, and an internal thread is provided in the rotating fixing member to cooperate with the top column;

[0016] The top column is movably arranged in the connecting column, and a prism is arranged at the lower end of the top column to cooperate with the first prism groove arranged on the inner side of the supporting leg column;

[0017] The adjusting button is mounted on the lower plate of the upper cylinder through a bearing, and a driving gear is arranged on the lower side of the adjusting button, and the driving gear is meshed with the inner side teeth of the synchronous belt;

[0018] The synchronous belt is arranged on the lower plate of the upper cylinder and meshes with the driven gear arranged on the rotating fixing member.

[0019] Preferably, the supporting leg is arranged in the connecting column through a spring, and a prismatic slot is arranged at the tail of the supporting leg, and a rubber base is arranged at the front end of the supporting leg, and the rubber base is used in conjunction with the overflow water tank; and a circle of balls is also embedded on the bottom wall of the open groove, and the balls are used in conjunction with the ball embedding groove arranged at the bottom of the rotating fixing part.

[0020] Preferably, the rotating fixing member and the driven gear are both provided with keyways for use with each other, and the keyways are used in conjunction with the positioning keys; the tail leg rod of the supporting leg is a prismatic rod, and the prismatic rod is used in conjunction with a second prismatic groove provided at the lower end inside the connecting column; the manual leveling assembly is a threaded adjustment rod, and the threaded adjustment rod is provided in the top column and is threadedly connected to the top column.

[0021] Preferably, the use process of the water permeability coefficient testing device includes:

[0022] Step S1. Use a steel ruler to measure the diameter D and thickness L of the cement concrete cylindrical specimen twice, remove the average value, and calculate the surface area A of the specimen accurately to 1 mm;

[0023] Step S2. Seal the sample with sealing materials or other means to prevent water leakage. Water only penetrates from the upper and lower surfaces of the sample.

[0024] Step S3. After the sealing material is solidified, place the sample in a water permeability vacuum device, evacuate to 90 kpa ± 1 kpa, and maintain for 30 minutes; while maintaining the vacuum, add enough water to cover the sample and make the water 50-80 mm higher than the sample, stop evacuating, soak for 20 minutes, and take it out;

[0025] Step S4. Put an airbag membrane on the sample and put it into the water permeability coefficient test device. Inflate the airbag membrane to seal the sample and the periphery of the lower cylinder; put it into the overflow water tank, open the water supply valve, let the airless water enter the container, and when water flows out of the overflow hole of the overflow water tank, adjust the water inlet to keep a certain water level in the permeable cylinder. After the water outflow from the overflow port of the overflow water tank and the overflow port of the permeable cylinder is stable, use a measuring cylinder to collect water from the water outlet, record the water outflow in five minutes, measure three times, take the average value, and complete the measurement of the water permeability coefficient of the sample under constant head difference;

[0026] Step S5. Use a steel ruler to measure the water level difference between the permeable sample tube and the overflow tank, accurate to 0.1 cm;

[0027] Step S6. Use a thermometer to measure the temperature of the water in the overflow tank during the test, accurate to 0.5°C;

[0028] Step S7. The water permeability coefficient should be calculated according to the following formula:

[0029]

[0030] K T - Water permeability coefficient of the specimen when the water temperature is T℃, in millimeters (mm / s);

[0031] Q - the amount of water seeping out in t seconds (mm 3 );

[0032] L - thickness of the specimen (mm);

[0033] A - upper surface area of ​​the specimen (mm 2 );

[0034] H - water level difference (mm);

[0035] T – time (s);

[0036] The test results are expressed as the average value of three samples, with a calculation accuracy of 1.0×10 -2 mm / s;

[0037] The water permeability coefficient at standard temperature is calculated according to the following formula:

[0038]

[0039] Where: K 15The water permeability coefficient of the sample at -15℃ water temperature, η T - Dynamic viscosity of water at T℃ (kPa·S), η 15 The dynamic viscosity of water at -15°C is

[0040] - Dynamic viscosity ratio of water.

[0041] Preferably, the first compression chamber is arranged at the upper end of the second compression chamber, and an exhaust hole and a third sensor mounting hole are provided on the side wall of the first compression chamber, and there are two exhaust holes, and one of the exhaust holes is connected to the vacuum pump through an air pipe, and the other exhaust hole is connected to the glass tube.

[0042] Preferably, the second pressurized chamber is arranged at the upper end of the third pressurized chamber through a flange fastener, and a second gas injection port is arranged on the side wall of the second pressurized chamber, the second gas injection port is connected to the air compressor through an air pipe, and a second sensor mounting hole is also arranged on the second pressurized chamber, and the second sensor mounting hole is used to install a pressure sensor.

[0043] Preferably, a first gas injection hole is provided on the side wall of the third pressurized chamber, and the first gas injection hole is connected to the gas outlet hole of the glass tube through a conduit, and a first sensor mounting hole is also provided on the side wall of the third pressurized chamber, and the first sensor mounting hole is used in conjunction with a pressure sensor, and an air permeable plate is also provided at the upper end of the third pressurized chamber.

[0044] Preferably, the air permeability test device can detect the air permeability of a sample and calculate the porosity of the sample.

[0045] The beneficial effects of the present invention are as follows: the present invention discloses a cement concrete permeability coefficient tester. Compared with the prior art, the present invention has the following improvements:

[0046] 1. The present invention designs a cement concrete permeability coefficient tester, which includes a water permeability coefficient test device and an air permeability coefficient test device. When in use, the water permeability coefficient test device and the air permeability coefficient test device are set so that the tester can be integrated to measure the water permeability coefficient and the air permeability coefficient of the cement concrete sample. At the same time, the water permeability coefficient test device and the air permeability coefficient test device can also be used crosswise, and the experimental functions are diverse and easy to use;

[0047] 2. In the water permeability coefficient test device, the height and level of the water permeable sample tube are adjusted by setting the height adjustment mechanism to complete the determination of the water permeability coefficient of the cement concrete sample under constant water head and variable water head pressure. At the same time, the device can also be used to determine the permeability coefficient and seepage performance of the cement concrete sample from the interface to the bottom under constant water flow conditions. It has various functions and is easy to use. At the same time, the setting of the sample sleeve effectively avoids water leakage on the side wall of the sample during the experiment, thereby ensuring the experimental accuracy.

[0048] 3. In the air permeability test device, by designing the pressure chamber into a multi-chamber structure including a first pressurized chamber, a second pressurized chamber and a third pressurized chamber which are interconnected, and by utilizing different gas injection methods and structures, the air permeability and porosity of the sample can be tested during use, which has the advantages of simple structure, easy use and high accuracy of experimental results. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of the cement concrete permeability coefficient testing instrument of the present invention.

[0050] Figure 2 It is a front view of the water permeability test device of the present invention.

[0051] Figure 3 It is a cross-sectional view of the water permeable sample tube of the present invention.

[0052] Figure 4 It is a partial enlarged view of the water permeable sample tube A of the present invention.

[0053] Figure 5 It is a cross-sectional view of the water permeable sample tube A of the present invention.

[0054] Figure 6 This is a partial enlarged view of the water permeable sample tube B of the present invention

[0055] Figure 7 It is a top view of the water permeable sample tube of the present invention.

[0056] Figure 8 It is a schematic structural diagram of the supporting leg of the present invention.

[0057] Fig. 9 It is a cross-sectional view of the rotating fixing member of the present invention.

[0058] Fig.10 It is a structural schematic diagram of the threaded adjusting rod of the present invention.

[0059] Fig.11 It is a cross-sectional view of the top column of the present invention.

[0060] Fig.12 It is a cross-sectional view of the connecting column of the present invention.

[0061] Fig.13 It is a schematic structural diagram of the air permeability coefficient experimental device of the present invention.

[0062] Fig.14 It is a schematic structural diagram of the pressure chamber of the present invention.

[0063] Fig.15 It is a schematic structural diagram of the third pressurized chamber of the present invention.

[0064] Fig.16 It is a schematic structural diagram of the first pressurized chamber and the second pressurized chamber of the present invention.

[0065] Among them: 1. frame, 2. vacuum pump, 21. precision regulating valve, 22. boat switch, 23. digital negative pressure gauge, 24. vibration-resistant pressure gauge, 25. full-scale recorder, 3. permeable sample cylinder, 31. water inlet pipe, 32. upper cylinder, 321. opening groove, 322. level bubble, 33. lower cylinder, 34. first overflow port, 35. sample sleeve, 36. leakage hole, 37. connecting column, 371. supporting leg, 3711. prismatic slot, 3712. rubber base, 372. spring, 373. threaded adjustment rod, 374. rotating fixing part, 3741. ball groove, 375. ball, 376. top column, 3761. prism, 377. first fastening nut , 378. second fastening nut, 379. second prismatic groove, 370. pressure plate, 38. adjusting button, 381. driving gear, 382. driven gear, 39. synchronous belt, 4. overflow tank, 41. second overflow port, 5. water collecting cylinder, 6. air compressor, 7. pressure chamber, 71. first pressurizing chamber, 711. exhaust hole, 72. second pressurizing chamber, 721. second air injection port, 722. second sensor mounting hole, 73. third pressurizing chamber, 731. first sensor mounting hole, 732. first air injection hole, 733. breathable plate, 74. flange fastener, 75. test membrane guard ring, 76. test membrane lower guard ring, 8. pressure sensor, 9. glass cylinder, 10. glass tube. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0067] Example 1: Refer to the attached Figure 1-16 The cement concrete permeability coefficient tester shown in the figure comprises a frame 1, a permeability coefficient test device arranged on the frame 1, and is used to measure the permeability coefficient of a cement concrete sample, comprising a permeable sample cylinder 3, an overflow tank 4 and a water collecting measuring cylinder 5.

[0068] The water permeable sample tube 3 is horizontally installed in the overflow tank 4 through a height adjustment mechanism, connected to a water source through a water inlet pipe 31, and a cement concrete sample is arranged at the lower end of the water permeable sample tube 3. When in use, water is supplied to the water permeable sample tube 3 through the water source to detect the water permeability of the sample;

[0069] The overflow water tank 4 is fixedly mounted on the frame 1, and a second overflow port 41 is arranged at the upper end of the overflow water tank 4. The water collecting measuring cylinder 5 is arranged at the lower side of the second overflow port 41, and is used to collect water overflowing from the second overflow port 41. When in use, the water collecting measuring cylinder 5 is used to collect the water overflowing from the second overflow port 41. By converting the volume of the collected water, the air permeability coefficient of the cement concrete sample can be calculated.

[0070] Preferably, in order to facilitate the installation of the sample, the water permeable sample tube 3 is designed to include a detachably connected upper tube 32 and a lower tube 33, wherein

[0071] The upper cylinder 32 is arranged at the upper end of the lower cylinder 33, and a first overflow port 34 is arranged on the upper cylinder 32 for controlling the liquid level in the upper cylinder 32. The water inlet pipe 31 is arranged at the water inlet at the upper end of the upper cylinder 32, and a control valve is also arranged on the water inlet pipe 31;

[0072] The lower cylinder 33 is installed at the lower end of the upper cylinder 32 through a connecting column 37, and the sample is fixedly installed in the lower cylinder 33 through a sample sleeve 35. The height adjustment mechanism is arranged on the lower cylinder 33, and a leakage hole 36 is also arranged at the center of the bottom plate of the lower cylinder 33, so that the water that passes through the sample can flow into the overflow tank 4 by utilizing the water level difference between the first overflow port 34 and the second overflow port 41, and then flow out through the second overflow port 41, so as to convert the water permeability of the sample.

[0073] Preferably, to prevent water leakage, a sealing ring 37 is provided between the upper cylinder 32 and the lower cylinder 33. At the same time, to prevent water leakage between the sample and the side wall of the lower cylinder 33 when the sample is placed in the lower cylinder 33 for experiment, the sample sleeve 35 is designed to be an airbag membrane, which can be inflated when in use to interact with the inner wall of the lower cylinder 33 and the sample, so as to fix the sample in the lower cylinder 33 and prevent water leakage at the same time, ensuring that water can only leak from the upper side of the sample.

[0074] Preferably, in order to facilitate the use of the connecting column 37 to connect the upper cylinder 32 with the lower cylinder 33, the connecting column 37 is designed to be a sleeve structure, and a pressure plate 370 is integrally formed at the upper end of the connecting column 37, and the pressure plate 370 is used in conjunction with the open groove 321 opened on the upper cylinder 32, and an external thread is provided on the connecting column 37 to be used in conjunction with a first fastening nut 377 and a second fastening nut 378 respectively, wherein the second fastening nut 378 is arranged on the lower side of the upper plate of the lower cylinder 33, and is used to tightly connect the lower plate of the upper cylinder 32 with the upper plate of the lower cylinder 33, and is placed when the upper cylinder 32 and the lower cylinder 33 are in use. The first fastening nut 377 is arranged on the lower side of the lower plate of the lower cylinder 33, and is used to tightly connect the upper plate and the lower plate of the lower cylinder 33, so that the upper plate and the lower plate of the lower cylinder 33 form an integral structure to limit and fix the sample sleeve 35.

[0075] Preferably, the height adjustment mechanism includes a linkage adjustment component and a manual leveling component that cooperate with each other. The linkage adjustment component is used to adjust the relative height of the support leg 371 at the lower end of the connecting column 37, thereby adjusting the height of the entire permeable sample tube 3 in the overflow tank 4. The manual leveling component is arranged in the connecting column 37, and is used to manually adjust the relative height of the support leg 371 when in use, so that the level bubble 322 on the permeable sample tube 3 is centered, thereby completing the leveling of the permeable sample tube 3 and ensuring the progress of the experiment.

[0076] Preferably, the support leg 371 is movably installed in the connecting column 37 via a spring 372 , and a prismatic slot 3711 is provided at the tail of the support leg 371 , and a rubber base 3712 is provided at the front end of the support leg 371 , and the rubber base 3712 is used in conjunction with the overflow tank 4 .

[0077] Preferably, in order to facilitate synchronous adjustment of the four supporting legs 371 at the lower ends of the four connecting columns 37 during use, the linkage adjustment assembly is designed to include a rotating fixing member 374, a top column 376, an adjustment button 38 and a synchronous belt 39, wherein

[0078] The rotating fixing member 374 is rotatably installed in the opening groove 321, and an internal thread is provided on the inner side of the rotating fixing member 374 to be screwed to the top column 376;

[0079] The top column 376 is movably installed in the connecting column 37, and a prism 3761 is provided at the lower end of the top column 376 for use in conjunction with a first prism groove 3711 provided on the inner side of the leg column of the supporting leg 371, that is, the height of the top column 376 is adjusted by rotating the rotating fixing member 374 so that the top column 376 is pressed on the supporting leg 371, thereby adjusting the extension amount of the lower end of the supporting leg 371;

[0080] The adjusting button 38 is rotatably mounted on the lower plate of the upper cylinder 32 via a bearing, and a driving gear 381 is provided on the lower side of the adjusting button 38, and the driving gear 381 is meshed with the inner teeth of the synchronous belt 39;

[0081] The synchronous belt 39 is arranged on the lower plate of the upper cylinder 32, and meshes with the driven gear 382 arranged on the rotating fixed part 374, that is, the rotating fixed part 374 is driven to rotate by rotating the adjusting button 38, thereby adjusting the height of the top column 376, and adjusting the extension amount of the lower end of the supporting leg 371, thereby completing the process of adjusting the height of the overall permeable sample tube 3 in the overflow tank 4, and completing the measurement of the permeability coefficient of the cement concrete sample under constant head and variable head pressure. At the same time, the device can also be used to measure the permeability coefficient and seepage performance of the cement concrete sample from the interface to the bottom under constant water flow conditions.

[0082] Preferably, in order to reduce the friction between the rotating fixing member 374 and the bottom wall of the opening groove 321 during the adjustment process, a circle of balls 375 is also embedded on the bottom wall of the opening groove 321. The balls 375 are used in conjunction with the ball embedding groove 3741 set at the bottom of the rotating fixing member 374. When in use, the sliding friction is converted into rolling friction through the action of the balls 375, thereby effectively reducing the friction between the rotating fixing member 374 and the bottom wall of the opening groove 321.

[0083] Preferably, in order to facilitate the fixed connection between the driven gear 382 and the rotating fixing member 374, the rotating fixing member 374 and the driven gear 382 are provided with key slots that cooperate with each other. When in use, the driven gear 382 is fixedly installed on the rotating fixing member 374 using the positioning key 383, thereby realizing the fixed connection between the driven gear 382 and the rotating fixing member 374.

[0084] Preferably, in order to prevent the coaxial rotation of the support leg 371 and the top column 376 from affecting the adjustment effect of the linkage adjustment assembly during the adjustment process, the tail leg rod of the support leg 371 is designed to be a prismatic rod, and is used in conjunction with the second prismatic groove 379 provided at the lower end of the inner part of the connecting column 37.

[0085] Preferably, in order to facilitate the adjustment of the relative height of the support legs 371 during use so that the level bubble 322 on the water-permeable sample tube 3 is centered, thereby completing the leveling of the water-permeable sample tube 3 and making the samples level, the manual leveling component is designed to be a threaded adjustment rod 373, and the threaded adjustment rod 373 is arranged in the top column 376 and is threadedly connected to the top column 376. When in use, the threaded adjustment rod 373 is manually adjusted so that the lower end of the threaded adjustment rod 373 adjusts the relative height of the support legs 371 so that the level bubble 322 is centered, thereby completing the leveling of the water-permeable sample tube 3 and ensuring the progress of the experiment.

[0086] Preferably, the water source is an airless water source, which is installed on the lower side of the frame 1 and connected to the water inlet pipe 31 through a water supply pump.

[0087] Preferably, the technical parameters of the water permeability test device described in this embodiment are:

[0088] (1) Cement concrete specimen size: φ100mm height ≥50mm;

[0089] (2) Water-permeable sample cylinder: φ100mm+0.2mm, divided into upper and lower parts, the upper cylinder 32 is 250mm high; the lower cylinder 33 is 100mm high;

[0090] (3) Water collecting cylinder: capacity is 2L, the minimum scale value is 1mL;

[0091] (4) Overflow tank: equipped with a second overflow port and capable of maintaining a moving water level;

[0092] (5) Stopwatch: used for timing, with an accuracy of 1 second;

[0093] (6) Steel ruler: measure water head difference, scale 0-300mm, graduation value 1mm;

[0094] (7) Sample vacuum saturation device: for sample pre-saturation treatment, a. Saturation container: made of stainless steel barrel, with negative pressure gauge on the top cover; b. Vacuum pump: negative pressure range -0.1MPa to 1 standard atmosphere.

[0095] The use process of the water permeability test device described in this embodiment includes:

[0096] Step S1. Use a steel ruler to measure the diameter D and thickness L of the cement concrete cylindrical specimen twice, remove the average value, and calculate the surface area A of the specimen accurately to 1 mm;

[0097] Step S2. Seal the sample with sealing materials or other means to prevent water leakage. Water only penetrates from the upper and lower surfaces of the sample.

[0098] Step S3. After the sealing material is solidified, place the sample in a water permeability vacuum device, evacuate to 90 kpa ± 1 kpa, and maintain for 30 minutes; while maintaining the vacuum, add enough water to cover the sample and make the water 50-80 mm higher than the sample, stop evacuating, soak for 20 minutes, and take it out;

[0099] Step S4. Put an airbag membrane on the sample and put it into the water permeability coefficient test device. Inflate the airbag membrane to seal the sample and the periphery of the lower cylinder; put it into the overflow water tank, open the water supply valve, let the airless water enter the container, and when water flows out of the overflow hole of the overflow water tank, adjust the water inlet to keep a certain water level (about 210mm) in the permeable cylinder. After the water outflow from the overflow port of the overflow water tank and the overflow port of the permeable cylinder is stable, use a measuring cylinder to collect water from the water outlet, record the water outflow (Q) in five minutes, measure three times, take the average value, and complete the measurement of the water permeability coefficient of the sample under constant head difference;

[0100] Step S5. Use a steel ruler to measure the water level difference (H) between the water level of the permeable sample tube and the water level of the overflow tank, accurate to 0.1 cm;

[0101] Step S6. Use a thermometer to measure the temperature (T) of the water in the overflow tank during the test, accurate to 0.5°C;

[0102] Step S7. The water permeability coefficient should be calculated according to the following formula:

[0103]

[0104] K T - Water permeability coefficient of the specimen when the water temperature is T℃, in millimeters (mm / s);

[0105] Q - the amount of water seeping out in t seconds (mm 3 );

[0106] L - thickness of the specimen (mm);

[0107] A - upper surface area of ​​the specimen (mm 2 );

[0108] H - water level difference (mm);

[0109] T – time (s);

[0110] The test results are expressed as the average value of three samples, with a calculation accuracy of 1.0×10 -2 mm / s;

[0111] This sample uses 15℃ water temperature as the standard temperature. The water permeability coefficient at the standard temperature should be calculated according to the following formula:

[0112]

[0113] Where: K 15 - Water permeability coefficient of the sample at standard temperature (mm / s), η T - Dynamic viscosity of water at T℃ (kPa·S), η 15 Dynamic viscosity of water at -15°C (kPa·S), - Dynamic viscosity ratio of water.

[0114] Embodiment 2: Different from Embodiment 1, in order to detect the air permeability of cement concrete samples, the cement concrete permeability coefficient tester also includes an air permeability coefficient test device, which includes a vacuum pump 2, an air compressor 6, a pressure chamber 7, a plexiglass cylinder 9, a glass tube 10 and a full-scale recorder 25 installed on a frame 1, wherein

[0115] The pressure chamber 7 is installed on the operating table of the vacuum pump 2, and includes, from top to bottom, a first pressurized chamber 71, a second pressurized chamber 72 and a third pressurized chamber 73 which are interconnected. A pressure sensor 8 is provided on each of the first pressurized chamber 71, the second pressurized chamber 72 and the third pressurized chamber 73. The pressure sensor 8 is connected to the full-scale recorder 25 through a connecting wire, and is used to record the gas pressure of each pressurized chamber in the pressure chamber 7 in real time. A sample is installed in the second pressurized chamber 72, and the first pressurized chamber 71, the second pressurized chamber 72 and the third pressurized chamber 73 are divided into three separate pressurized chambers by the sample.

[0116] The air compressor 6 is connected to the second pressurized chamber 72 via a pressurized air pipe, and is used to provide gas pressure into the second pressurized chamber 72;

[0117] The air inlet of the glass cylinder 9 is connected to the air compressor 6, and the air outlet is connected to the third pressurized chamber 73 through an air pipe, so as to inflate the third pressurized chamber 73;

[0118] The exhaust hole of the first pressurized chamber 71 is connected to the vacuum pump 2 and the glass tube 10 through air pipes, respectively, so as to exhaust the gas in the first pressurized chamber 71 through the vacuum pump 2 .

[0119] Preferably, in order to facilitate timely gas injection into the third pressurized chamber 73, a first gas injection hole 732 is provided on the side wall of the third pressurized chamber 73, and the first gas injection hole 732 is connected to the gas outlet of the glass tube 9 through a conduit. When in use, gas is injected into the third pressurized chamber 73 through the air compressor 6; at the same time, a first sensor mounting hole 731 is also provided on the side wall of the third pressurized chamber 73, and the first sensor mounting hole 731 is used to install the pressure sensor 8 to monitor the gas pressure in the third pressurized chamber 73 in real time. At the same time, in order to facilitate the installation of the sample, a breathable plate 733 is also provided at the upper end of the third pressurized chamber 73.

[0120] Preferably, the sample is installed on the air permeable plate 733 through a test membrane lower protective ring 76 and a test membrane upper disassembly piece 77, and a test membrane protective ring 75 is provided on the lower side of the test membrane upper disassembly piece 77 to protect the sample.

[0121] Preferably, the second pressurized chamber 72 is installed on the upper end of the third pressurized chamber 73 through a flange fastener 74. To facilitate the injection of gas into the second pressurized chamber 72 to detect the air permeability of the sample, a second gas injection port 721 is provided on the side wall of the second pressurized chamber 72. The second gas injection port 721 is connected to the air compressor 6 through an air pipe. When in use, the air compressor 6 is used to inject gas into the second pressurized chamber 72 for pressurization. At the same time, in order to monitor the gas pressure at different positions of the sample in real time, a second sensor mounting hole 722 is also provided on the second pressurized chamber 72. The second sensor mounting hole 722 is used to install a pressure sensor 8 to monitor the gas pressure at different positions of the sample in real time and detect the air permeability of the sample.

[0122] Preferably, the first compression chamber 71 is arranged at the upper end of the second compression chamber 72, and an exhaust hole 711 and a third sensor mounting hole 712 are arranged on the side wall of the first compression chamber 71, wherein two exhaust holes 711 are arranged, and one of the exhaust holes 711 is connected to the vacuum pump 2 through an air pipe, and is used to evacuate the first compression chamber 71 to a vacuum using the vacuum pump 2, and the other exhaust hole 711 is connected to the glass tube 10, and the gas change process is observed by observing the gas change in the glass tube 10 to observe whether the cement concrete permeability experiment has started, and at the same time, the experimental process of the cement concrete permeability experiment is observed.

[0123] The experimental process of the air permeability coefficient experimental device in this embodiment includes:

[0124] Test 1: Test of air permeability of sample:

[0125] Step S1. First, install the test piece in the pressure chamber, connect the various gas-filled pipes and electrical wires, and debug the lines after the installation is complete, and observe through the glass cylinder and glass tube to see whether the experiment is going on;

[0126] Step S2. After the above pipelines are properly connected and the test can be carried out, the vacuum pump and the air compressor are turned on. When it is detected that the amount of gas input in a single time is the same as the amount of gas output, the sample is saturated, and the air in the pressure chamber 7 is extracted to carry out the experiment and record it;

[0127] Step S3. Use a stopwatch to record the inflation time, the gas pressure in each pressurized chamber, the gas volume in the first pressurized chamber 71 and other data, and calculate the sample permeability coefficient based on the experimentally measured data.

[0128] Test 2: Calculation of sample porosity:

[0129] Step S1. Before installing the sample, connect each gas-filled tube and wire line, debug after the line is installed, and observe through the glass cylinder and glass tube to see whether the experiment is carried out;

[0130] Step S2. When observing that the device can operate, install the sample in the pressure chamber, and after the sample is installed, open the switches of each pipeline, and use a stopwatch to record the inflation time and the gas pressure and gas volume in each pressurized chamber;

[0131] Step S3. Finally, the porosity of the sample is calculated based on the pressure difference and gas volume difference between the first pressurized chamber 71 and the third pressurized chamber 73.

[0132] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A cement concrete permeability tester, characterized in that: It comprises a frame, a water permeability coefficient test device and an air permeability coefficient test device arranged on the frame; The water permeability coefficient test device comprises a water permeable sample cylinder, an overflow water tank and a water collecting graduated cylinder. The water permeable sample cylinder is arranged in the overflow water tank through a height adjustment mechanism, connected to a water source through a water inlet pipe, and a cement concrete sample is arranged at the lower end of the water permeable sample cylinder; the overflow water tank is fixedly mounted on a frame, and a second overflow port is arranged at the upper end of the overflow water tank, and the water collecting graduated cylinder is arranged at the lower side of the second overflow port and is used in conjunction with the second overflow port; The air permeability coefficient test device comprises a vacuum pump, an air compressor, a pressure chamber, a plexiglass cylinder, a glass tube and a full-scale recorder installed on a frame. The pressure chamber is arranged on the operating table of the vacuum pump, and comprises, from top to bottom, a first pressurized chamber, a second pressurized chamber and a third pressurized chamber which are interconnected. The first pressurized chamber, the second pressurized chamber and the third pressurized chamber are all provided with pressure sensors, and the pressure sensors are connected to the full-scale recorder through connecting wires. A sample is installed in the second pressurized chamber; the air compressor is connected to the second pressurized chamber through an air pipe; the air inlet of the glass cylinder is connected to the air compressor, and the air outlet is connected to the third pressurized chamber through an air pipe; the air extraction hole of the first pressurized chamber is connected to the vacuum pump and the glass tube through air pipes respectively; The water permeable sample tube comprises an upper tube body and a lower tube body which are detachably connected. The upper cylinder is arranged at the upper end of the lower cylinder, and a first overflow port is arranged on the upper cylinder, the water inlet pipe is arranged at the water inlet at the upper end of the upper cylinder, and a control valve is arranged on the water inlet pipe; The lower cylinder is arranged at the lower end of the upper cylinder through a connecting column, the sample is fixed in the lower cylinder through a sample sleeve, the height adjustment mechanism is arranged on the lower cylinder, and a leakage hole is also arranged on the bottom plate of the lower cylinder; The connecting column is a sleeve structure, and a pressure plate is arranged at the upper end of the connecting column, and the pressure plate is used in conjunction with the opening groove on the upper cylinder. The connecting column is also provided with external threads, which are used in conjunction with the first fastening nut and the second fastening nut respectively; The height adjustment mechanism includes a linkage adjustment component and a manual leveling component that cooperate with each other, and the linkage adjustment component includes a rotating fixing part, a top column, an adjustment button and a synchronous belt. The rotating fixing member is rotatably installed in the open groove, and an internal thread is provided in the rotating fixing member to cooperate with the top column; The top column is movably arranged in the connecting column, and a prism is arranged at the lower end of the top column to cooperate with the first prism groove arranged on the inner side of the supporting leg column; The adjusting button is mounted on the lower plate of the upper cylinder through a bearing, and a driving gear is arranged on the lower side of the adjusting button, and the driving gear is meshed with the inner side teeth of the synchronous belt; The synchronous belt is arranged on the lower plate of the upper cylinder and meshes with the driven gear arranged on the rotating fixing member.

2. A cement concrete permeability tester according to claim 1, characterized in that: The supporting leg is arranged in the connecting column through a spring, and a prismatic slot is arranged at the tail of the supporting leg, and a rubber base is arranged at the front end of the supporting leg, and the rubber base is used in conjunction with the overflow water tank; and a circle of balls is also embedded on the bottom wall of the open groove, and the balls are used in conjunction with the ball embedding groove arranged at the bottom of the rotating fixing part.

3. A cement concrete permeability tester according to claim 1, characterized in that: The rotating fixing member and the driven gear are both provided with keyways for use with each other, and the keyways are used in conjunction with the positioning keys; the tail leg rod of the supporting leg is a prismatic rod, and the prismatic rod is used in conjunction with a second prismatic groove provided at the lower end inside the connecting column; the manual leveling assembly is a threaded adjustment rod, and the threaded adjustment rod is provided in the top column and is threadedly connected to the top column.

4. A cement concrete permeability tester according to any one of claims 1 to 3, characterized in that: The use process of the water permeability coefficient test device includes: Step S1. Use a steel ruler to measure the diameter D and thickness L of the cement concrete cylindrical specimen twice, remove the average value, and calculate the surface area A of the specimen accurately to 1 mm; Step S2. Seal the sample with sealing materials or other means to prevent water leakage. Water only penetrates from the upper and lower surfaces of the sample. Step S3. After the sealing material is solidified, place the sample in a water permeability vacuum device, evacuate to 90 kpa ± 1 kpa, and maintain for 30 minutes; while maintaining the vacuum, add enough water to cover the sample and make the water 50-80 mm higher than the sample, stop evacuating, soak for 20 minutes, and take it out; Step S4. Put an airbag membrane on the sample and put it into the water permeability coefficient test device. Inflate the airbag membrane to seal the sample and the periphery of the lower cylinder; put it into the overflow water tank, open the water supply valve, let the airless water enter the container, and when water flows out of the overflow hole of the overflow water tank, adjust the water inlet to keep a certain water level in the permeable cylinder. After the water outflow from the overflow port of the overflow water tank and the overflow port of the permeable cylinder is stable, use a measuring cylinder to collect water from the water outlet, record the water outflow in five minutes, measure three times, take the average value, and complete the measurement of the water permeability coefficient of the sample under constant head difference; Step S5. Use a steel ruler to measure the water level difference between the permeable sample tube and the overflow tank, accurate to 0.1 cm; Step S6. Use a thermometer to measure the temperature of the water in the overflow tank during the test, accurate to 0.5°C; Step S7. The water permeability coefficient should be calculated according to the following formula: ； K T - Water permeability coefficient of the specimen when the water temperature is T℃, in millimeters (mm / s); Q - the amount of water seeping out in t seconds (mm 3 ); L - thickness of the specimen (mm); A - upper surface area of ​​the specimen (mm 2 ); H - water level difference (mm); T – time (s); The test results are expressed as the average value of three samples, with a calculation accuracy of 1.0×10 -2 mm / s; The water permeability coefficient at standard temperature is calculated according to the following formula: ； Where: K 15 The water permeability coefficient of the sample at -15℃ water temperature, η T - Dynamic viscosity of water at T℃ , η 15 The dynamic viscosity of water at -15°C is 5. A cement concrete permeability tester according to claim 1, characterized in that: The first compression chamber is arranged at the upper end of the second compression chamber, and an exhaust hole and a third sensor mounting hole are arranged on the side wall of the first compression chamber. There are two exhaust holes, and one of the exhaust holes is connected to the vacuum pump through an air pipe, and the other exhaust hole is connected to the glass tube.

6. A cement concrete permeability tester according to claim 1, characterized in that: The second pressurized chamber is arranged at the upper end of the third pressurized chamber through a flange fastener, and a second gas injection port is arranged on the side wall of the second pressurized chamber. The second gas injection port is connected to the air compressor through an air pipe, and a second sensor mounting hole is also arranged on the second pressurized chamber. The second sensor mounting hole is used to install a pressure sensor.

7. A cement concrete permeability tester according to claim 1, characterized in that: A first gas injection hole is arranged on the side wall of the third pressurized chamber, and the first gas injection hole is connected to the gas outlet hole of the glass tube through a conduit. A first sensor mounting hole is also arranged on the side wall of the third pressurized chamber, and the first sensor mounting hole is used in conjunction with a pressure sensor. A gas permeable plate is also arranged at the upper end of the third pressurized chamber.

8. A cement concrete permeability tester according to any one of claims 5 to 7, characterized in that: The air permeability test device can detect the air permeability of a sample and calculate the porosity of the sample.

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