CN115561143A - Concrete water vapor permeability coefficient detection and minimum contact area measurement device and method - Google Patents
Concrete water vapor permeability coefficient detection and minimum contact area measurement device and method Download PDFInfo
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- CN115561143A CN115561143A CN202211392514.7A CN202211392514A CN115561143A CN 115561143 A CN115561143 A CN 115561143A CN 202211392514 A CN202211392514 A CN 202211392514A CN 115561143 A CN115561143 A CN 115561143A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 273
- 239000004567 concrete Substances 0.000 title claims abstract description 110
- 230000035699 permeability Effects 0.000 title claims abstract description 99
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000001514 detection method Methods 0.000 title claims abstract description 23
- 238000005259 measurement Methods 0.000 title claims abstract description 11
- 230000035515 penetration Effects 0.000 claims abstract description 15
- 238000012360 testing method Methods 0.000 claims description 193
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 41
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 41
- 239000012188 paraffin wax Substances 0.000 claims description 41
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 41
- 239000007788 liquid Substances 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 27
- 238000002474 experimental method Methods 0.000 claims description 24
- 238000007789 sealing Methods 0.000 claims description 16
- 230000008859 change Effects 0.000 claims description 15
- 238000010998 test method Methods 0.000 claims description 9
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 3
- 238000000691 measurement method Methods 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 75
- 230000008569 process Effects 0.000 description 13
- 230000008595 infiltration Effects 0.000 description 7
- 238000001764 infiltration Methods 0.000 description 7
- 239000011148 porous material Substances 0.000 description 5
- 238000005303 weighing Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000001680 brushing effect Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 238000007781 pre-processing Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000009738 saturating Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
- G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/0806—Details, e.g. sample holders, mounting samples for testing
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Abstract
The invention provides a concrete water vapor permeability coefficient detection and minimum contact area measurement device and a method, wherein the method comprises the following steps: measuring the minimum penetration contact area of the concrete; measuring the gas permeability of the concrete; the water permeability of the concrete was measured. The invention provides a device and a method for detecting the water vapor permeability coefficient and measuring the minimum contact area of concrete, which have high concentration and wide experimental pressure range and meet the actual condition. The method accurately, quickly and intuitively expresses the permeability of the concrete in real time.
Description
Technical Field
The invention relates to the field of concrete performance measurement, in particular to a device and a method for detecting water vapor permeability coefficient and measuring minimum contact area of concrete.
Technical Field
The water and gas permeability of concrete refers to the property of water or gas penetrating into or through the concrete under the action of gradient pressure, is an important index of the durability of the concrete, and is generally measured by a permeability coefficient, and the size of the concrete mainly depends on the pore structure and the number of harmful pores (including the number of non-capillary pores and the number of large capillary pores) of the concrete. Two types of permeation media, water and gas, are currently used in determining this property. The internal pore structure of concrete is not only related to the durability such as permeability, air tightness and corrosion resistance, but also affects the toughness and pressure resistance of concrete.
In the experimental process of concrete permeability test, the situation that the permeability is unstable can appear when the permeation contact area of gas, water and concrete is small, most of the situations are smaller than the actual permeability coefficient of concrete, and the permeability tends to be stable along with the increase of the permeation contact area. The reason is that large seepage channels exist between the surface and the interior of the concrete, the permeation movement of the gas and the water is mainly carried out through the large seepage channels, and the probability of containing the large seepage channels is small when the contact area of the gas and the water with the concrete is small. And the large seepage porosity on the cross section of the concrete test block with small contact area has more difference compared with the whole large seepage porosity regardless of containing or not containing the large seepage channel. The measured permeability coefficient is representative only when the large seepage channel rate tends to be stable when the contact area reaches a certain size, so that the calculation and the measurement of the minimum seepage contact area of the concrete have important significance.
In the traditional concrete water permeability experiment, a concrete impermeability instrument is used for measuring the concrete permeability coefficient by referring to the industry standard SL/T352-2020 Hydraulic concrete experiment specification, and the method takes the water seepage height of the sectional area under certain pressure as the basis to obtain the concrete impermeability grade and impermeability coefficient. The permeability grade obtained by the experiment is the average value of the whole permeability process, the permeability process cannot be observed in real time, discontinuous data in the experiment process is lost, and the linear relation between the permeability height and the time in the permeability process cannot be proved. According to research, the concrete water infiltration process is an unstable process, and the water infiltration process is characterized in that the water infiltration process is promoted and hindered by capillary siphon effect at the early infiltration stage and the later infiltration stage respectively. Therefore, the calculation of the concrete permeability coefficient by using the traditional concrete impermeability instrument cannot meet the current demand, and a new experimental method and equipment are urgently needed to be developed, so that the permeation condition of water in concrete can be observed in real time in a full process, and the reasonable analysis can be made on the permeation process of the concrete.
The method adopts a steady state seepage method, obtains the volume of the concrete test block seepage water under a constant pressure gradient in the test process, and calculates the water permeability coefficient of the concrete according to the Darcy formula through the change of the seepage quantity of the water in the concrete along with the time. Placing the prepared standard concrete test block into the permeameter of the invention, opening the air pump to pressurize to initial pressure of 0.8Mpa, observing the water seepage amount of the gas-liquid outlet 24, if the water seepage amount is less than 1.7 x 10 -3 ml/min, requiredGradually increasing water pressure by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 -3 ml/min, the maximum pressure can not exceed 1.5Mpa, the pressure is kept stable, the 5 readings of the water pressure gauge are observed, the test is started after the reading of the pressure gauge is stable and the seepage is stable, the reading is recorded once every 15-30 min, the reading is finished after 16h, and the relevant numerical value of the water permeability is calculated.
At present, no determined unified standard exists for a method for measuring the gas permeability coefficient of concrete. The method mostly refers to Shu Lin air permeability test in the prior art, and adopts a negative pressure mode, a vacuum pump is used for pumping out cavity air to be lower than normal pressure by 99kPa, then a valve is closed, and the time when the vacuum pressure reaches 95kPa is taken as the time for starting the test. The time required for the vacuum to reach a pressure of 70kPa was measured. And calculating the gas permeability coefficient of the concrete according to the Darcy formula and the volume and pressure change of the cavity. Shu Lin air permeability test can reflect the gas permeability of concrete in the test process, but has the problems of difficult sealing and low negative pressure strength.
The invention relates to a Shu Lin ventilation method, and a positive pressure and extrusion sealing mode is adopted to perform a gas permeation resistance test on concrete. According to the change of the gas pressure in the cavity along with the time, the permeation condition of the gas in the concrete is reflected, and the high limit value of the gas pressure is greatly improved compared with the Shu Lin ventilation method. Therefore, it is necessary to design a device and a method for detecting the water vapor permeability coefficient and measuring the minimum contact area of concrete.
Disclosure of Invention
The invention aims to provide a device and a method for detecting the water vapor permeability coefficient and measuring the minimum contact area of concrete, which have high concentration and wide experimental pressure range and meet the actual condition. The method accurately, quickly and intuitively expresses the permeability of the concrete in real time.
In order to achieve the purpose, the invention provides the following scheme:
a concrete water vapor permeability coefficient detection and minimum contact area measurement device comprises: the test block placing device comprises an upper machine body part, a test block placing part, a lower machine body, a rack and a computer, wherein the lower machine body is sleeved outside the upper machine body part, the test block placing part is positioned inside the lower machine body and the upper machine body part, the lower machine body is placed on the rack, and the upper machine body part is electrically connected with the computer;
the upper machine body part comprises an air inlet part, an upper machine body and a liquid level detection device, the air inlet part is arranged at the top of the upper machine body, an upper cavity is arranged inside the upper machine body, the liquid level detection device is arranged on the side part of the upper machine body and communicated with the upper cavity, and the liquid level detection device is electrically connected with the computer;
a lower cavity is formed in the lower machine body, a gas-water outlet is formed in the bottom of the lower machine body, and the gas-water outlet is communicated with the lower cavity;
the test block placing part comprises a test block placing cavity, a test block fixing part, a gasket adjusting part and a temperature control device, the bottom of the upper cavity is arranged on the upper portion of the gasket adjusting part, the test block fixing part is arranged on the upper portion of the upper cavity, the upper cavity is communicated with the gasket adjusting part, the bottom of the gasket adjusting part is arranged on the bottom of the test block placing cavity, the bottom of the test block placing cavity is arranged on the lower cavity, the junction of the test block placing cavity and the lower cavity is arranged on the test block fixing part, the upper machine body is connected with the lower machine body through the test block fixing part, the inside of the placing cavity is arranged on the test block, and the temperature control device is arranged on the outer side of the lower part of the upper machine body.
The water inlet part comprises a water inlet part and a water outlet part;
the water inlet part comprises a water tank, a water pressure pump and a water inlet pipe, the water pressure pump is arranged on the water tank and is connected with the water inlet pipe, the water inlet pipe is communicated with the upper cavity, the water seal valve, the water pressure gauge protection valve and the water pressure intensity transmitter are arranged on the water inlet pipe, and the water pressure intensity transmitter is electrically connected with the computer;
the air inlet part comprises an air booster pump and an air inlet pipe, the air booster pump is connected with the air inlet pipe, the air inlet pipe is communicated with the upper cavity, the air inlet pipe is provided with a gas sealing valve, a gas pressure gauge protection valve and a gas pressure transmitter, and the gas pressure transmitter is electrically connected with the computer.
The test block fixing piece comprises a gasket adjusting baffle, a fixing plate, a nut and a screw rod, the gasket adjusting baffle is arranged at the junction of the gasket adjusting part and the upper cavity, the fixing plate is arranged at the junction of the test block placing cavity and the lower cavity, the gasket adjusting baffle and the fixing plate are correspondingly provided with a plurality of screw holes, and the screw rod penetrates through the screw holes and is fixed through the nut;
the gasket adjusting part comprises a gasket and a gasket adjusting area, the gasket is placed in the gasket adjusting area, and the gasket is arranged between the lower part of the gasket adjusting baffle and the upper part of the test block;
the diameter of the test block is smaller than that of the test block placing cavity, paraffin and rosin mixtures are coated on the side face of the test block in a rolling mode, the interiors of the gasket adjusting baffle plate, the gasket and the fixing plate are hollow, and paraffin and rosin mixtures are coated on the upper contact face and the lower contact face of the gasket.
The liquid level detection device comprises a liquid level meter and an automatic liquid level meter reader, the liquid level meter is arranged at the outer side part of the upper cavity and is communicated with the inner part of the upper cavity, the automatic liquid level meter reader is arranged on the liquid level meter, and the automatic liquid level meter reader is in communication connection with a computer;
the temperature control device comprises a heat tracing band and a temperature control box, the heat tracing band is wound outside the lower half part of the upper machine body, and the temperature control box is electrically connected with the heat tracing band.
A concrete water vapor permeability coefficient detection and minimum contact area measurement method comprises the following steps:
content 1: measuring the minimum penetration contact area of the concrete;
content 2: measuring the gas permeability of the concrete;
content 3: the water permeability of the concrete was measured.
The concrete minimum penetration contact area is measured, and the concrete minimum penetration contact area specifically comprises the following steps:
step 101: pre-treating a test block before testing;
step 102: the upper machine body is placed on the rack in an inverted mode, a gasket is placed on a gasket adjusting baffle, a layer of paraffin and rosin mixture is coated on the surface of the gasket, a test block is placed in the test block placing cavity in an inverted mode, and the gasket is compressed;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting nuts of the upper machine body and the lower machine body through screw holes by using a plurality of bolts, screwing the nuts, standing for 30min, and rightly placing the machine body;
step 103: opening a water seal valve, a water pressure gauge protection valve, a gas seal valve and a gas pressure gauge protection valve, opening a water pressure pump to enable water to fill 2/3 of the volume of the upper cavity, closing the water pressure pump, and connecting an air booster pump;
step 104: closing the water seal valve, pressurizing by using the air booster pump, observing the water seepage quantity of the air-water outlet when the initial pressure is 0.8Mpa, and if the water seepage quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased gradually under 0.1Mpa until the water seepage quantity is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 105: calculating the water permeability of the concrete according to the change condition of the reading of the water pressure meter along with the time;
step 106: according to the test method, gaskets with different inner diameters are respectively placed in the gasket adjusting areas, and the step 104 and the step 105 are repeated to carry out test and measurement;
step 107: drawing according to different contact areas and permeability coefficients, wherein when the permeability coefficient is not changed along with the increase of the contact area, the contact area is the minimum permeability contact area;
measuring the water permeability of the concrete, specifically:
step 201: pretreating a test block before testing;
step 202: determining a proper gasket according to a minimum permeation contact area test, inversely placing the upper machine body on a rack, placing the gasket on a gasket adjusting baffle, coating a layer of paraffin and rosin mixture on the surface of the gasket, inversely placing the test block in a test block placing cavity, and pressing the gasket;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting nuts of an upper machine body and a lower machine body through screw holes by using a plurality of bolts, screwing the nuts, standing for 30min, rightly arranging the machine bodies, and connecting an air booster pump;
step 203: opening a water seal valve, a water pressure gauge protection valve, a gas seal valve and a gas pressure gauge protection valve, opening a water pressure pump to enable water to fill 2/3 of the volume of the upper cavity, closing the water pressure pump, and connecting an air booster pump;
step 204: closing the water seal valve, pressurizing by using the air booster pump, observing the water seepage quantity of the air-water outlet when the initial pressure is 0.8Mpa, and if the water seepage quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 205: observing the readings of the water pressure gauge, wherein the readings of the water pressure gauge are stable and the seepage rate of the gas-water outlet is stable, the starting time is the experiment starting time, clicking a starting button on computer software, recording the seepage rate of the gas-water outlet at intervals of fixed time, finishing the experiment after 16h, and clicking an ending button on a computer;
step 206: and (3) calculating the concrete water permeability according to the change condition of the indication of the water pressure meter along with time:
ΔP＝P i -P a
in the formula: q is the mean flow, V w Is penetrated by the test block liquidThe amount of output,. DELTA.t is the test time,. DELTA.P is the differential pressure value, P i The stable air pressure in the cavity is the reading of a water pressure gauge, pa is the atmospheric pressure, and K w Is the water permeability coefficient, mu 2 Is water viscosity coefficient of 0.8949 × 10 -6 (kPa. S), L is the concrete block height, and A represents the block cross-sectional area.
Measuring the gas permeability of the concrete, specifically:
step 301: pretreating a test block before testing;
step 302: determining a proper gasket according to the minimum permeation contact area, inverting the upper body on the rack, placing the gasket on a gasket adjusting baffle, coating a layer of paraffin and rosin mixture on the surface of the gasket, inverting the test block in the test block placing cavity, and compressing the gasket;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting nuts of an upper machine body and a lower machine body through screw holes by using a plurality of bolts, screwing the nuts, standing for 30min, rightly arranging the machine bodies, and connecting an air booster pump;
step 303: closing the water sealing valve and the water pressure gauge protection valve, opening the gas sealing valve and the gas pressure gauge protection valve, opening the air booster pump, closing the gas sealing valve when the reading of the gas pressure gauge is greater than 770kPa, and closing the air booster pump;
step 304: observing the reading of the gas pressure gauge, wherein the start time is the start time of the experiment when the reading of the gas pressure gauge is reduced to 750kPa, clicking a start button on computer software, and clicking an end button on the computer when the experiment is ended when the reading of the gas pressure gauge is reduced to 650 kPa;
step 305: and (3) calculating the concrete gas permeability according to the change of the indication number of the gas pressure gauge along with the time:
ΔP＝P i -P f
ΔP m ＝P m -P a
in the formula: p is i Is the starting pressure in the test, P f For pressure falling to a certain value, Δ P is the differential pressure value, P m Is the mean upper cavity pressure, Δ P, over a certain time m Is the difference between the upper and lower pressure values of the test block, P n Is the mean pressure in the test block, P a At atmospheric pressure, Q m Is the average gas flow in the test block, V t The volume of the upper cavity, Δ t, test time, μ 1 Is a gas viscosity coefficient, air is 2.2X 10 -5 (Pa.S), L is the concrete block height, A is the block cross-sectional area, K g Is the gas permeability coefficient.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a schematic view of the overall structure of a concrete water vapor permeability coefficient measuring and minimum contact area measuring device;
fig. 2 is a graph of permeability coefficient minimum contact area.
Reference numerals: 1. a gas seal valve; 2. a gas pressure gauge; 3. a gas gauge protection valve; 4. a water pressure gauge protection valve; 5. a water pressure gauge; 6. a water seal valve; 7. an air inlet pipe; 8. a water inlet pipe; 9. a water pressure transmitter; 10. an air booster pump; 11. a water tank; 12. a water pressure pump; 13. mounting the machine body; 14. an upper cavity; 15. a liquid level meter; 16. a level gauge automatic reader; 17. a gasket adjusting baffle; 18. a pad conditioning region; 19. a gasket; 20. a test block placing cavity; 21. testing blocks; 22. a lower machine body; 23. a lower cavity; 24. a gas-water outlet; 25. a screw hole; 26. a nut; 27. a screw; 28. a computer; 29. a rack; 30. a heat tracing band; 31. a temperature control box; 32. a fixing plate; 33. a gas pressure transmitter.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a device and a method for detecting the water vapor permeability coefficient and measuring the minimum contact area of concrete, which have high concentration and wide experimental pressure range and meet the actual condition. The method accurately, quickly and intuitively expresses the permeability of the concrete in real time.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1, the present invention provides a device for detecting water vapor permeability coefficient and measuring minimum contact area of concrete, comprising: the test device comprises an upper machine body 13, a test block 21 placing part, a lower machine body 22, a rack 29 and a computer 28, wherein the lower machine body 22 is sleeved outside the upper machine body, the test block 21 placing part is positioned inside the lower machine body 22 and the upper machine body part, the lower machine body 22 is placed on the rack 29, and the upper machine body is electrically connected with the computer 28;
the upper machine body comprises an air inlet part, an upper machine body 13 and a liquid level detection device, the air inlet part is arranged at the top of the upper machine body 13, an upper cavity 14 is arranged inside the upper machine body 13, the liquid level detection device is arranged on the side part of the upper machine body 13 and communicated with the upper cavity 14, and the liquid level detection device is electrically connected with the computer 28;
the lower machine body 22 is of an inverted convex cylindrical structure, a lower cavity 23 is arranged in the lower part of the lower machine body, an air water outlet 24 is arranged at the bottom of the lower machine body 22, and the air water outlet 24 is communicated with the lower cavity 23;
the test block 21 placing part comprises a test block placing cavity 20, a test block fixing piece, a gasket adjusting part and a temperature control device, the bottom of the upper cavity 14 is arranged on the upper portion of the gasket adjusting part, the test block fixing piece is arranged on the upper cavity 14, the gasket adjusting part is communicated with the upper cavity 14, the bottom of the gasket adjusting part is arranged on the test block placing cavity 20, the bottom of the test block placing cavity 20 is arranged on the lower cavity 23, the junction of the test block placing cavity 20 and the lower cavity 23 is provided with the test block fixing piece, the upper machine body 13 is connected with the lower machine body 22 through the test block fixing piece, the inner part of the placing cavity is provided with the test block 21, and the outer side of the lower part of the upper machine body 13 is provided with the temperature control device.
The water inlet part comprises a water inlet part and a water outlet part;
the water inlet part comprises a water tank 11, a water pressure pump 12 and a water inlet pipe 8, the water pressure pump 12 is arranged on the water tank 11, the water pressure pump 12 is connected with the water inlet pipe 8, the water inlet pipe 8 is communicated with the upper cavity 14, the water seal valve 6, the water pressure gauge 5, the water pressure gauge protection valve 4 and the water pressure transmitter 9 are arranged on the water inlet pipe 8, and the water pressure transmitter 9 is electrically connected with the computer 28;
the air inlet part comprises an air booster pump 10 and an air inlet pipe 7, the air booster pump 10 is connected with the air inlet pipe 7, the air inlet pipe 7 is communicated with the upper cavity 14, the air inlet pipe 7 is provided with an air seal valve 1, an air pressure gauge 2, an air pressure gauge protection valve 3 and an air pressure transmitter 33, the air pressure transmitter 33 is electrically connected with the computer 28, and one embodiment of the invention is as follows: the inlet tube 8 is two Y types with intake pipe 7, and intake pipe 7 diameter, inlet tube 8 diameter are known different diameters.
The test block fixing piece comprises a gasket adjusting baffle 17, a fixing plate 32, a nut 26 and a screw 27, the gasket adjusting baffle 17 is arranged at the junction of the gasket adjusting part and the upper cavity 14, the adjusting baffle 17 is hollow inside, the fixing plate 32 is arranged at the junction of the test block placing cavity 20 and the lower cavity 23, the fixing plate 32 is hollow inside, the gasket adjusting baffle 17 and the fixing plate 32 are correspondingly provided with a plurality of screw holes 25, and the screw 27 penetrates through the screw holes 25 and is fixed through the nut 26;
the gasket adjusting part comprises a gasket 19 and a gasket adjusting area 18, the gasket 19 is placed in the gasket adjusting area 18, and the gasket 19 is arranged between the lower part of the gasket adjusting baffle 17 and the upper part of the test block 21;
the diameter of the test block 21 is slightly smaller than that of the test block placing cavity 20, paraffin and rosin mixtures are coated on the side face of the test block 21 in a rolling mode, holes are formed in the middle of the gasket 19 of the gasket adjusting baffle 17 and the middle of the fixing plate 32, and the paraffin and rosin mixtures are coated on the upper contact face and the lower contact face of the gasket 19.
The liquid level detection device comprises a liquid level meter 15 and a liquid level meter automatic reader 16, the liquid level meter 15 is arranged at the outer side part of the upper cavity 14 and is communicated with the inside of the upper cavity 14, the liquid level meter 15 is provided with the liquid level meter automatic reader 16, and the liquid level meter automatic reader 16 is in communication connection with the computer 28;
the temperature control device comprises a heat tracing band 30 and a temperature control box 31, wherein the heat tracing band 30 is wound outside the lower half part of the upper machine body 13, and the temperature control box 31 is electrically connected with the heat tracing band 30.
A concrete water vapor permeability coefficient detection and minimum contact area measurement method comprises the following steps:
content 1: measuring the minimum penetration contact area of the concrete;
content 2: measuring the gas permeability of the concrete;
content 3: the water permeability of the concrete was measured.
The concrete minimum penetration contact area is measured, and the concrete minimum penetration contact area is specifically as follows:
step 101: preprocessing a test block 21 before testing;
step 102: the upper machine body 13 is placed on the rack 29 in an inverted mode, the gasket 19 is placed on the gasket adjusting baffle 17 of the gasket 19, a layer of paraffin and rosin mixture is coated on the surface of the gasket 19, the test block 21 is placed in the test block placing cavity 20 in an inverted mode, and the gasket 19 is compressed;
a power supply of the temperature control box 31 is turned on to raise the temperature of the heat tracing band 30, and a heat transfer gun is used for injecting the rosin and paraffin solution along the inner wall of the upper machine body 13 until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body 13;
connecting nuts 26 of the upper machine body 22 and the lower machine body 22 through screw holes 25 by using a plurality of bolts, screwing the nuts, standing for 30min, and rightly placing the machine bodies;
step 103: opening a water seal valve 6, a water pressure gauge protection valve 4, a gas seal valve 1 and a gas pressure gauge protection valve 3, opening a water pressure pump 12 to fill 2/3 of the volume of the upper cavity 14 with water, and connecting an air booster pump 10;
step 104: closing the water seal valve 6, pressurizing by using the air booster pump 10, observing the seepage water quantity at the air-water outlet 24 when the initial pressure is 0.8Mpa, and if the seepage water quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 105: calculating the water permeability of the concrete according to the change of the indication of the water pressure meter 5 along with the time;
step 106: according to the test method, the gaskets 19 with different inner diameters are respectively placed in the gasket adjusting areas 18, and the step 104 and the step 105 are repeated to carry out the test and the measurement;
step 107: drawing according to different contact areas and permeability coefficients, wherein when the permeability coefficient is not changed along with the increase of the contact area, the contact area is the minimum permeability contact area;
measuring the water permeability of the concrete, specifically:
step 201: preprocessing a test block 21 before testing;
step 202: determining a proper gasket 19 according to a minimum penetration contact area test, inverting the upper machine body 13 on the rack 29, placing the gasket 19 on the gasket adjusting baffle 17 of the gasket 19, coating a layer of paraffin and rosin mixture on the surface of the gasket 19, inverting the test block 21 in the test block placing cavity 20, and compressing the gasket 19;
a power supply of the temperature control box 31 is turned on to raise the temperature of the heat tracing band 30, and a paraffin and rosin solution is injected along the inner wall of the upper machine body 13 by using a heat liquid transfer gun until the paraffin and rosin mixture is flush with the bottom edge of the upper machine body 13;
a plurality of bolts 27 are used for connecting nuts 26 of the upper machine body 22 and the lower machine body 22 through screw holes 25, so that the upper machine body and the lower machine body are screwed tightly, and after standing for 30min, the machine bodies are rightly arranged, connected with the air booster pump 10 and connected with the air booster pump 10;
step 203: opening the water seal valve 6, the water pressure gauge protection valve 4, the gas seal valve 1 and the gas pressure gauge protection valve 3, opening the water pressure pump 12 to fill 2/3 of the volume of the upper cavity 14 with water, and closing the water pressure pump 12;
step 204: closing the water seal valve 6, pressurizing by using the air booster pump 10, observing the seepage water quantity at the air-water outlet 24 when the initial pressure is 0.8Mpa, and if the seepage water quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased gradually under 0.1Mpa until the water seepage quantity is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 205: observing the readings of the water pressure gauge 5, wherein the readings of the water pressure gauge 5 are stable, and the seepage quantity of the gas-water outlet 24 is stable, the experiment starting time is set, the starting button is clicked on the software of the computer 28, the seepage quantity of the gas-water outlet 24 is recorded at fixed intervals, after 16h, the experiment is finished, and the finishing button is clicked on the computer 28;
step 206: according to the change condition of the readings of the water pressure meter 5 along with the time, the water permeability of the concrete is calculated as follows:
ΔP＝P i -P a
in the formula: q is the average flow per time period, V w For the liquid penetration of test piece 21, V1 is the volume of water at the beginning of the test, V n For the volume of water at a certain time in the test,. DELTA.t is the time between two recordings,. DELTA.P is the differential pressure value, P i To start the air pressure, P a At atmospheric pressure, K w Is the water permeability coefficient, mu 2 Is water viscosity coefficient of 0.8949 × 10 -6 (kPa. S), L is the concrete block height, and A represents the block cross-sectional area.
Measuring the gas permeability of the concrete, specifically:
step 301: preprocessing a test block 21 before testing;
step 302: determining a proper gasket 19 according to the minimum contact area, inverting the upper machine body 13 on the rack 29, placing the gasket 19 on the gasket adjusting baffle 17 of the gasket 19, coating a layer of paraffin and rosin mixture on the surface of the gasket 19, inverting the test block 21 in the test block placing cavity 20, and compressing the gasket 19;
a power supply of the temperature control box 31 is turned on to raise the temperature of the heat tracing band 30, and a paraffin and rosin solution is injected along the inner wall of the upper machine body 13 by using a heat liquid transfer gun until the paraffin and rosin mixture is flush with the bottom edge of the upper machine body 13;
a plurality of bolts 27 are used for connecting nuts 26 of the upper machine body 22 and the lower machine body through screw holes 25, so that the upper machine body and the lower machine body are screwed tightly, and after standing for 30min, the machine bodies are rightly arranged and connected with the air booster pump 10;
step 303: closing the water seal valve 6 and the water pressure gauge protection valve 4, opening the gas seal valve 1 and the gas pressure gauge protection valve 3, opening the air booster pump 10, closing the gas seal valve 1 when the reading of the gas pressure gauge 2 is greater than 770kPa, and closing the air booster pump 10;
step 304: observing the indication number of the gas pressure gauge 2, wherein the indication number of the gas pressure gauge 2 is the experiment starting time when reaching 750kPa, clicking a starting button on the software of the computer 28, and clicking an ending button on the computer 28 after the experiment is ended when the indication number of the gas pressure gauge 2 is reduced to 650 kPa;
step 205: according to the change of the readings of the gas pressure gauge 2 along with the time, the gas permeability of the concrete is calculated as follows:
ΔP＝P i -P f
ΔP m ＝P m -P a
in the formula: p i Is the starting pressure in the test, P f For pressure at a certain value, Δ P is the differential pressure value, P m Is the average pressure, Δ P, of the upper cavity 14 over time m Is the difference between the upper and lower pressure values of the test block 21, P n Is the average pressure, P, in the test block 21 a At atmospheric pressure, Q m Is the average flow, V, in the test block 21 t Volume of the upper cavity 14,. DELTA.t is the test time,. Mu. 1 Is gas viscosity coefficient of 2.2 × 10 -5 (Pa.S), L is the concrete block height, A is the block cross-sectional area, K g Is the gas permeability coefficient.
One embodiment of the present invention is:
minimum contact area test method:
step 101: preparing concrete materials, preparing test blocks 21 with the diameter of 150mm and the height of 150mm according to test proportion, wherein the number of each test block 21 to be tested is 2;
step 102: curing the block to be tested for 28 days or 56 days according to the standard of concrete physical and mechanical property test method standard (GB/T50081-2019);
step 103: after the test age is reached, taking out the test block 21, wiping the test block to be clean, requiring the upper bottom and the lower bottom of the test block 21 to be smooth surfaces, polishing the test block to be smooth if the test block is not smooth, and brushing the circular surface with the diameter of 60mm at the central part of the upper top surface by a steel wire brush;
after the test block 21 is weighed, the vacuum water saturation is carried out for more than 8 hours, and the weighing is carried out after the water saturation, so that the water retention degree of the test block 21 reaches more than 40 percent.
Step 104: sealing the surface of the cylinder by adding paraffin and rosin, and airing for 30min at room temperature;
step 105: the upper machine body 13 is placed on the rack 29 upside down, a gasket 19 with the outer diameter of 150mm and the inner diameter of 50mm is placed on the gasket adjusting baffle 17, a layer of paraffin and rosin mixture is coated on the surface of the gasket 19, the test block 21 is placed in the test block placing cavity 20 upside down, and the gasket 19 is compressed;
opening a power supply of the temperature control box 31 to enable the temperature of the heat tracing band 30 to rise to the temperature that the paraffin and the rosin are melted, injecting a paraffin and rosin solution along the inner wall of the upper machine body 13 by using a hot liquid transferring gun until the paraffin and rosin mixture is flush with the bottom of the upper machine body 13, closing the power supply of the temperature control box 31, and enabling the paraffin and rosin mixture to be completely and hermetically jointed with the inner wall of the upper machine body 13 after solidification;
a plurality of bolts 27 are used for connecting the upper machine body 13 and the lower machine body 22 through screw holes 25 and nuts 26, so that the upper machine body and the lower machine body are screwed tightly, the device is arranged upright after standing for 30min, and the water inlet pipe 8 is connected with the water pressure pump 12;
step 106: opening a water seal valve 6, a water pressure gauge protection valve 4, a gas seal valve 1 and a gas pressure gauge protection valve 3, opening a water pressure pump 12 to fill 2/3 of the volume of the upper cavity 14 with water, and connecting an air booster pump 10;
step 107: closing the water seal valve 6, pressurizing by using the air booster pump 10, observing the seepage water quantity at the air-water outlet 24 when the initial pressure is 0.8Mpa, and if the seepage water quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased gradually under 0.1Mpa until the water seepage quantity is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 108: by passingThe time and pressure change rule obtained by the test uses a Darcy formula:
calculating to obtain the water permeability of the test block 21:
ΔP＝P i -P a
in the formula: q is the average flow per time period, V w For the liquid penetration of test piece 21, V1 is the volume of water at the beginning of the test, V n For the volume of water at a certain time in the test,. DELTA.t is the time between two recordings,. DELTA.P is the differential pressure value, P i To start the air pressure, P a At atmospheric pressure, K w Is the water permeability coefficient, mu 2 Is water viscosity coefficient of 0.8949 × 10 -6 (kPa. S), L is the concrete block height, and A represents the block cross-sectional area.
Step 109: according to the test method, the gaskets 19 with inner diameters of 60mm,70mm,80mm,90mm,100mm and 120mm are respectively placed in the gasket adjusting areas 18, and the steps 105 to 108 are repeated;
step 110: drawing according to different contact areas and permeability coefficients, wherein when the permeability coefficient is not changed along with the increase of the contact area, the contact area is the minimum contact area A1;
water penetration test:
step 201: preparing concrete materials, preparing test blocks 21 with the diameter of 150mm and the height of 150mm according to test proportion, wherein the number of each test block 21 to be tested is 2;
step 202: curing the block to be tested for 28 days or 56 days according to the standard of concrete physical and mechanical property test method standard (GB/T50081-2019);
step 203: after the test age is reached, taking out the test block 21, wiping the test block to be clean, requiring the upper bottom and the lower bottom of the test block 21 to be smooth surfaces, polishing the test block to be smooth if the test block is not smooth, and brushing the circular surface with the diameter of 60mm at the central part of the upper top surface by a steel wire brush;
step 204: determining the minimum infiltration contact area A1 according to the minimum contact area infiltration test, and replacing the inner hole area A2 of the gasket 19 (A2 is more than A1);
step 205: weighing the test block 21, saturating the test block with water for more than 8 hours in vacuum, weighing the test block after water saturation to enable the water retention degree of the test block 21 to reach more than 40%, sealing the surface part of the column body by adding paraffin and rosin, and airing the column body for 30min at room temperature;
step 206: calculating the volume of the upper cavity 14, opening the gas sealing valve 1, the gas pressure gauge protection valve 3, the water sealing valve 6, the water pressure gauge protection valve 4, opening the water pressure pump 12 to fill 2/3 of the volume of the upper cavity 14 with water, closing the water sealing valve 6, opening the air booster pump 10 to pressurize, wherein the initial pressure is 0.8Mpa, observing the seepage water amount at the gas-water outlet 24, and if the seepage water amount is less than 1.7 x 10 -3 The water pressure of the water pump is increased by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 207: observing the indication of a water pressure meter 6, starting an experiment when the indication of the water pressure meter is stable and the seepage quantity of the gas-water outlet is stable, recording the seepage quantity of the gas-water outlet 24 once every 15-30 minutes, finishing the experiment after 16 hours, and clicking a finishing button on a computer;
step 208: and calculating the water permeability of the test block 21 according to the time and pressure change rule obtained by the test:
ΔP＝P i -P a
in the formula: q is the average flow per time period，V w For the liquid penetration of test piece 21, V1 is the volume of water at the beginning of the test, V n For the volume of water at a certain time in the test,. DELTA.t is the time between two recordings,. DELTA.P is the differential pressure value, P i To start the air pressure, P a At atmospheric pressure, K w Is the water permeability coefficient, mu 2 Is water viscosity coefficient of 0.8949 × 10 -6 (kPa. S), L is the concrete block height, and A represents the block cross-sectional area.
Gas permeability test method:
step 301: determining the minimum contact area A2 according to the minimum penetration test, and replacing the gasket 19 corresponding to the minimum contact area A3 (A3 > A2);
step 302: preparing concrete materials, preparing test blocks 21 with the diameter of 150mm and the height of 150mm according to test proportion, wherein the number of each test block 21 to be tested is 2;
step 303: curing the block to be tested for 28 days or 56 days according to the standard of concrete physical and mechanical property test method standard (GB/T50081-2019);
step 304: after the test age is reached, taking out the test block 21, wiping the test block cleanly, requiring the upper bottom and the lower bottom of the test block 21 to be smooth surfaces, if the test block is not smooth, polishing the test block smoothly, and brushing a circular surface with the diameter of 60mm at the center of the upper top surface by using a steel wire brush;
weighing the test block 21, putting the test block into an oven, drying for 7 days at the drying temperature of 60 ℃, and weighing the dried test block 21 to calculate the initial water content;
step 305: sealing the surface of the cylinder by adding paraffin and rosin, and airing for 30min at room temperature;
step 306: closing the water seal valve 6 and the water pressure gauge protection valve 4, opening the gas seal valve 1, the gas pressure gauge protection valve 3 and the air booster pump 10, and closing the gas seal valve 1 and the air booster pump 10 when the reading of the gas pressure gauge 2 reaches more than 770 kPa;
step 307: observing the indication number of the gas pressure gauge 2, clicking a start button on the software of the computer 28 when the indication number of the gas pressure gauge 2 is reduced to 750kPa, ending the test when the indication number of the gas pressure gauge 2 is reduced to 650kPa, and clicking an end button on the computer;
step 309: and calculating the gas permeability of the test block 21 by using a Darcy formula according to the time and pressure change rule obtained by the test:
ΔP＝P i -P f
ΔP m ＝P m -P a
in the formula: p i Is the starting pressure in the test, P f For pressure falling to a certain value, Δ P is the differential pressure value, P m Is the mean upper cavity pressure, Δ P, over a given time m Is the difference between the upper and lower pressure values of the test block, P n Is the mean pressure in the test block, P a At atmospheric pressure, Q m To average the flow in the test block, V t The volume of the upper cavity, Δ t, test time, μ 1 Is a gas viscosity coefficient of 2.2X 10 -5 (Pa.S), L is the concrete block height, A is the block cross-sectional area, K g Is the gas permeability coefficient.
According to the device and the method for detecting the water vapor permeability coefficient and measuring the minimum contact area of the concrete, provided by the invention, the contact area can be changed by changing the size of the gasket, and an experiment for researching the minimum contact area can be carried out; the water inlet is closed during the gas permeation experiment, the gas inlet is closed during the water permeation experiment, gas and water can be respectively stored in the upper cavity, the device can simultaneously realize the concrete gas permeability, water permeability and minimum contact area detection tests, and the device has high concentration; the concrete permeation experiment is carried out in a pressurization mode, the experiment pressure range is wide, and the actual situation is met; the computer is used for recording the data of the pressure gauge, so that the permeability of the concrete is accurately, quickly and intuitively expressed in real time.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.
Claims (8)
1. The utility model provides a concrete aqueous vapor permeability coefficient detects and minimum area of contact survey device which characterized in that includes: the test block placing device comprises an upper machine body part, a test block placing part, a lower machine body, a rack and a computer, wherein the lower machine body is sleeved outside the upper machine body part, the test block placing part is positioned inside the lower machine body and the upper machine body part, the lower machine body is placed on the rack, and the upper machine body part is electrically connected with the computer;
the upper machine body part comprises an air inlet part, an upper machine body and a liquid level detection device, the air inlet part is arranged at the top of the upper machine body, an upper cavity is arranged inside the upper machine body, the liquid level detection device is arranged on the side part of the upper machine body and communicated with the upper cavity, and the liquid level detection device is electrically connected with the computer;
a lower cavity is formed in the lower machine body, a gas-water outlet is formed in the bottom of the lower machine body, and the gas-water outlet is communicated with the lower cavity;
the test block placing part comprises a test block placing cavity, a test block fixing part, a gasket adjusting part and a temperature control device, the bottom of the upper cavity is arranged on the upper portion of the gasket adjusting part, the test block fixing part is arranged on the upper portion of the upper cavity, the upper cavity is communicated with the gasket adjusting part, the bottom of the gasket adjusting part is arranged on the bottom of the test block placing cavity, the bottom of the test block placing cavity is arranged on the lower cavity, the junction of the test block placing cavity and the lower cavity is arranged on the test block fixing part, the upper machine body is connected with the lower machine body through the test block fixing part, the inside of the placing cavity is arranged on the test block, and the temperature control device is arranged on the outer side of the lower part of the upper machine body.
2. The concrete moisture permeability coefficient detection and minimum contact area determination apparatus of claim 1, wherein the water inlet portion comprises an air inlet portion and a water inlet portion;
the water inlet part comprises a water tank, a water pressure pump and a water inlet pipe, the water pressure pump is arranged on the water tank and is connected with the water inlet pipe, the water inlet pipe is communicated with the upper cavity, the water seal valve, the water pressure gauge protection valve and the water pressure intensity transmitter are arranged on the water inlet pipe, and the water pressure intensity transmitter is electrically connected with the computer;
the air inlet part comprises an air booster pump and an air inlet pipe, the air booster pump is connected with the air inlet pipe, the air inlet pipe is communicated with the upper cavity, the air inlet pipe is provided with a gas sealing valve, a gas pressure gauge protection valve and a gas pressure transmitter, and the gas pressure transmitter is electrically connected with the computer.
3. The device for detecting the water vapor permeability coefficient and measuring the minimum contact area of the concrete according to claim 1, wherein the test block fixing member comprises a gasket adjusting baffle, a fixing plate, a nut and a screw rod, the gasket adjusting baffle is arranged at the junction of the gasket adjusting part and the upper cavity, the fixing plate is arranged at the junction of the test block placing cavity and the lower cavity, the gasket adjusting baffle and the fixing plate are correspondingly provided with a plurality of screw holes, and the screw rod penetrates through the screw holes and is fixed through the nut;
the gasket adjusting part comprises a gasket and a gasket adjusting area, the gasket is placed in the gasket adjusting area, and the gasket is arranged between the lower part of the gasket adjusting baffle and the upper part of the test block;
the diameter of the test block is smaller than that of the test block placing cavity, paraffin and rosin mixtures are coated on the side face of the test block in a rolling mode, the interiors of the gasket adjusting baffle plate, the gasket and the fixing plate are hollow, and paraffin and rosin mixtures are coated on the upper contact face and the lower contact face of the gasket.
4. The concrete water gas permeability coefficient detection and minimum contact area measurement device according to claim 1, wherein the liquid level detection device comprises a liquid level meter and an automatic liquid level meter reader, the liquid level meter is arranged at the outer side of the upper cavity and is communicated with the inner part of the upper cavity, the automatic liquid level meter reader is arranged on the liquid level meter, and the automatic liquid level meter reader is in communication connection with a computer;
the temperature control device comprises a heat tracing band and a temperature control box, the heat tracing band is wound outside the lower half part of the upper machine body, and the temperature control box is electrically connected with the heat tracing band.
5. A concrete water vapor permeability coefficient detection and minimum contact area measurement method is applied to the concrete water vapor permeability coefficient detection and minimum contact area measurement device of any one of claims 1 to 4, and is characterized by comprising the following steps:
content 1: measuring the minimum penetration contact area of the concrete;
content 2: measuring the gas permeability of the concrete;
content 3: the water permeability of the concrete was measured.
6. The method for detecting the water vapor permeability coefficient and determining the minimum contact area of the concrete according to claim 5, wherein the method for measuring the minimum contact area of the concrete comprises the following steps:
step 101: pretreating a test block before testing;
step 102: the upper machine body is placed on the rack in an inverted mode, a gasket is placed on a gasket adjusting baffle, a layer of paraffin and rosin mixture is coated on the surface of the gasket, a test block is placed in the test block placing cavity in an inverted mode, and the gasket is compressed;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting upper and lower body nuts through screw holes by using a plurality of bolts, screwing the upper and lower body nuts, standing for 30min, and rightly placing the body;
step 103: opening a water seal valve, a water pressure gauge protection valve, a gas seal valve and a gas pressure gauge protection valve, opening a water pressure pump to enable water to fill 2/3 of the volume of the upper cavity, closing the water pressure pump, and connecting an air booster pump;
step 104: closing the water seal valve, pressurizing by using the air booster pump, observing the water seepage quantity of the air-water outlet when the initial pressure is 0.8Mpa, and if the water seepage quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 105: calculating the water permeability of the concrete according to the change condition of the readings of the water pressure meter along with the time;
step 106: according to the test method, gaskets with different inner diameters are respectively placed in the gasket adjusting areas, and the step 104 and the step 105 are repeated to carry out test and measurement;
step 107: and (4) drawing according to different contact areas and permeability coefficients, wherein when the permeability coefficient is not changed along with the increase of the contact area, the contact area is the minimum permeation contact area.
7. The method for detecting the water vapor permeability coefficient and determining the minimum contact area of the concrete according to claim 6, wherein the concrete water permeability is measured by:
step 201: pretreating a test block before testing;
step 202: determining a proper gasket according to a minimum penetration contact area test, inverting the upper body on the rack, placing the gasket on a gasket adjusting baffle, coating a layer of paraffin and rosin mixture on the surface of the gasket, inverting the test block in the test block placing cavity, and compressing the gasket;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting nuts of an upper machine body and a lower machine body through screw holes by using a plurality of bolts, screwing the nuts, standing for 30min, rightly arranging the machine bodies, and connecting an air booster pump;
step 203: opening a water seal valve, a water pressure gauge protection valve, a gas seal valve and a gas pressure gauge protection valve, opening a water pressure pump to fill 2/3 of the volume of the upper cavity with water, closing the water pressure pump, and connecting an air booster pump;
step 204: closing the water seal valve, pressurizing by using the air booster pump, observing the seepage water quantity of the air-water outlet when the initial pressure is 0.8Mpa, and if the seepage water quantity is less than 1.7 x 10 -3 The water pressure of the water pump is increased by 0.1Mpa until the water seepage amount is stable and is more than or equal to 1.7 x 10 ml/min -3 ml/min, the maximum pressure can not exceed 1.5Mpa, and the pressure is kept stable;
step 205: observing the readings of the water pressure meter, wherein the readings of the water pressure meter are stable and the seepage quantity of the gas-water outlet is stable, the experiment starting time is set, a starting button is clicked on computer software, the seepage quantity of the gas-water outlet is recorded at intervals of fixed time, after 16h, the experiment is finished, and an ending button is clicked on the computer;
step 206: and (3) calculating the concrete water permeability according to the change condition of the indication of the water pressure meter along with time:
ΔP＝P i -P a
in the formula: q is the mean flow, V w Delta t is the test time, delta P is the differential pressure value,P i the stable air pressure in the cavity is the reading of a water pressure gauge, pa is the atmospheric pressure, and K w Is the water permeability coefficient, mu 2 Is water viscosity coefficient of 0.8949 × 10 -6 (kPa. S), L is the concrete block height, and A represents the block cross-sectional area.
8. The method for detecting the water vapor permeability coefficient and determining the minimum contact area of the concrete according to claim 6, wherein the concrete gas permeability is measured by:
step 301: pretreating a test block before testing;
step 302: determining a proper gasket according to the minimum permeation contact area, inverting the upper body on the rack, placing the gasket on a gasket adjusting baffle, coating a layer of paraffin and rosin mixture on the surface of the gasket, inverting the test block in the test block placing cavity, and compressing the gasket;
opening a power supply of the temperature control box to raise the temperature of the heat tracing band, and injecting the rosin and paraffin solution along the inner wall of the upper machine body until the mixture of the paraffin and the rosin is flush with the bottom of the upper machine body;
connecting nuts of an upper machine body and a lower machine body through screw holes by using a plurality of bolts, screwing the nuts, standing for 30min, rightly arranging the machine bodies, and connecting an air booster pump;
step 303: closing the water sealing valve and the water pressure gauge protection valve, opening the gas sealing valve and the gas pressure gauge protection valve, opening the air booster pump, closing the gas sealing valve when the reading of the gas pressure gauge is greater than 770kPa, and closing the air booster pump;
step 304: observing the reading of the gas pressure gauge, wherein the start time is the start time of the experiment when the reading of the gas pressure gauge is reduced to 750kPa, clicking a start button on computer software, and clicking an end button on the computer when the experiment is ended when the reading of the gas pressure gauge is reduced to 650 kPa;
step 305: and (3) calculating the concrete gas permeability according to the change of the indication number of the gas pressure gauge along with the time:
ΔP＝P i -P f
ΔP m ＝P m -P a
in the formula: p i Is the starting pressure in the test, P f For pressure falling to a certain value, Δ P is the differential pressure value, P m Is the mean upper cavity pressure, Δ P, over a certain time m Is the difference between the upper and lower pressure values of the test block, P n Is the mean pressure in the test block, P a At atmospheric pressure, Q m Is the average gas flow in the test block, V t The volume of the upper cavity, Δ t, test time, μ 1 Is a gas viscosity coefficient, air is 2.2X 10 -5 (Pa.S), L is the concrete block height, A is the block cross-sectional area, K g Is the gas permeability coefficient.
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