CN116297106A

CN116297106A - Concrete gas permeability test device

Info

Publication number: CN116297106A
Application number: CN202310342726.2A
Authority: CN
Inventors: 高健琳; 吕建福; 毛继泽; 许强; 刘广智; 尤少斌; 郭轶宏
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2023-03-31
Filing date: 2023-03-31
Publication date: 2023-06-23

Abstract

The invention relates to the technical field related to concrete tests, in particular to a concrete gas permeability test device, which comprises: the environment simulation system is arranged in the second cavity and comprises a gas-liquid injection port, a detection assembly and a heating device; the liquid and the gas enter the second cavity through the gas-liquid injection port, the heating device is used for heating the liquid, and the detection component is used for detecting the temperature value, the humidity value and the pressure value in the second cavity; the gas measurement system is arranged in the first cavity and is used for measuring the volume of gas penetrating into the first cavity through the concrete test piece; and the test piece fixing system is used for fixing the concrete test piece. The concrete gas permeability test device can be used for carrying out gas permeability test and real-time monitoring of temperature field and moisture distribution on concrete test pieces under the coupling action of different high-temperature, high-humidity and high-pressure environmental conditions.

Description

Concrete gas permeability test device

Technical Field

The invention relates to the technical field related to concrete tests, in particular to a concrete gas permeability test device under the coupling action of high temperature, high humidity and high pressure.

Background

Concrete is a porous multiphase medium with a large number of pores inside, and under the effect of a pressure gradient, gas will migrate from a high pressure zone to a low pressure zone through the communicating pores in the material. The property that allows gas to be transported in the pore structure of concrete is the gas permeability of the concrete. It can be seen that the pore structure inside the concrete, in particular the amount of interconnected pores, is a major factor affecting its gas permeability. In addition, liquid-phase water exists in the concrete, and the existence of the water can occupy a gas flowing channel, so that the gas permeability of the concrete is reduced, and the pore water saturation of the concrete is also an important index for influencing the gas permeability of the concrete. When the saturation of the pore water in the concrete rises to a certain critical value, the communicating pores are all blocked, and the gas in the concrete stops flowing.

Environmental conditions in which concrete structures are in service, such as temperature, humidity, gas pressure, can also affect the gas permeability of the concrete. Under the drive of temperature, humidity and pressure gradient, heat and water vapor can be conducted and permeated into the concrete, so that the distribution of a temperature and humidity field in the concrete is affected. The specific effects are mainly manifested in the following four aspects: firstly, moisture easily enters the interior of the concrete structure so as to contact unhydrated cement particles, and the unhydrated cement particles are further hydrated by the rise of the temperature, so that the pore structure of the concrete is changed; secondly, the concrete is heated to generate free water evaporation and bound water dehydration, and the pores of the concrete are also increased, and even microcracks are generated; thirdly, the water content of the concrete is increased, the ventilation pores are reduced, and meanwhile, the temperature gradient, the humidity gradient and the pore pressure gradient in the concrete can promote the migration of the water in the concrete, so that a local high saturation phenomenon similar to wet resistance is formed; and fourthly, pore pressure in the concrete can expand microcracks, so that transmission channels of capillary water and water vapor are increased, and mass transfer of water into the concrete wall is promoted.

The walls of the containment concrete structure generally have larger thickness, and the temperature, the moisture distribution, the pore structure and the gas permeability of the walls are time-varying and non-uniform under the coupling action of high temperature, high humidity and high pressure, so that in order to reflect the variation, the gas permeability test under the high temperature, high humidity and high pressure environment needs to be carried out by adopting concrete test pieces consistent with the thickness of the walls. In the existing test methods, the laboratory measurement methods are difficult to measure large test pieces, and the in-situ test method is difficult to apply high-temperature, high-humidity and high-pressure environment conditions, so that a special test device is required to be designed to study the problem. Gas permeability is an important sign of concrete durability and is the first line of defense for concrete durability. The method has the advantages that the gas permeability of the concrete is studied deeply, the permeation mechanism is known, the durability evaluation and the residual life prediction of the in-service concrete structure are carried out, the method can also be used for carrying out the durability prediction of new projects, the method has important significance in improving the design level of projects and the service life of buildings, and the carbon discharge of the projects is reduced.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the problems that in the test method in the prior art, the laboratory measurement method is difficult to measure a large test piece, and the in-situ test method is difficult to apply high-temperature, high-humidity and high-pressure environmental conditions, so as to provide the concrete gas permeability test device.

In order to solve the technical problems, the invention provides a concrete gas permeability test device, which comprises: the environment simulation system is arranged in the second cavity and comprises a gas-liquid injection port, a detection assembly and a heating device; the liquid and the gas enter the second cavity through the gas-liquid injection port, the heating device is used for heating the liquid, and the detection component is used for detecting the temperature value, the humidity value and the pressure value in the second cavity; the gas measurement system is arranged in the first cavity and is used for measuring the volume of gas penetrating into the first cavity through the concrete test piece; the test piece fixing system is arranged between the environment simulation system and the gas measurement system and is used for fixing a concrete test piece, the concrete test piece has a set gradient, and a sensor group is arranged in the concrete test piece.

Further, a combined gas permeability test device or two implementations of an adjustable environmental condition type gas permeability measurement device are included.

Further, the detection component of the environment simulation system comprises an environment temperature sensor, a humidity sensor and an air pressure sensor, wherein the environment temperature sensor is used for detecting a temperature value in the second cavity, the humidity sensor is used for detecting a humidity value in the second cavity, and the air pressure sensor is used for detecting a pressure value in the second cavity; the environment simulation system further comprises a ceramic cushion block, and the heating device is arranged on the ceramic cushion block.

Further, the method comprises the steps of: the cylinder body is arranged on the fixing frame and comprises a first steel cylinder and a second steel cylinder, a first cavity is formed in the first steel cylinder, and a second cavity is formed in the second steel cylinder; a supporting structure is arranged between the first steel cylinder and the second steel cylinder and is used for supporting a concrete test piece; the heat insulation piece is arranged on the outer wall of the cylinder body; and the sealing structure is arranged between the first cavity and the second cavity and is used for sealing the concrete test piece, the first cavity and the second cavity.

Further, the gas measurement system of the combined gas permeability test apparatus includes: the temperature and humidity sensor is arranged in the first cavity; the liquid meter penetrates through the cylinder body and stretches into the first cavity, and the liquid meter is used for detecting the volume of liquid in the first cavity; the water tank penetrates through the cylinder body and stretches into the first cavity, and the water tank is used for detecting one end, far away from the concrete test piece, of the first cavity; the metering device is connected with the water tank; the gas measurement system further comprises a timing camera for timing the recording of the amount of water in the liquid meter and the metering device.

Further, the gas measurement system of the adjustable environmental condition type gas permeability measurement device comprises a gas collection device and a sealing rubber sleeve, wherein the gas collection device is sleeved at the top of the concrete test piece, and the sealing rubber sleeve is used for the first cavity.

Further, the concrete gas permeability test device also comprises a safety protection system, wherein the safety protection system comprises a steel wire mesh, an organic glass cover and a fuse, the steel wire mesh and the organic glass cover are arranged on the periphery of the device, so that the gas leakage phenomenon in the test process is prevented, and the inside high-temperature high-pressure gas burns test personnel; the heating device and each circuit are provided with fuses.

Further, the combined gas permeability test device further comprises a cooling water circulation system which is arranged on the outer wall of the cylinder body and used for cooling the cylinder body.

Further, the adjustable environmental condition type gas permeability measuring device further comprises a circulating gas injection port and a circulating gas discharge port, wherein the circulating gas injection port and the circulating gas discharge port are arranged on the cavity wall of the second cavity.

Further, the sensor group comprises a test piece temperature sensor, a resistivity sensor and a gas pressure sensor, and the test piece temperature sensor, the resistivity sensor and the gas pressure sensor are arranged in the concrete test piece in a staggered manner.

The technical scheme of the invention has the following advantages:

1. the invention provides a concrete gas permeability test device, which comprises: the environment simulation system is arranged in the second cavity and comprises a gas-liquid injection port, a detection assembly and a heating device; the liquid and the gas enter the second cavity through the gas-liquid injection port, the heating device is used for heating the liquid, and the detection component is used for detecting the temperature value, the humidity value and the pressure value in the second cavity; the gas measurement system is arranged in the first cavity and is used for measuring the volume of gas penetrating into the first cavity through the concrete test piece; the test piece fixing system is arranged between the environment simulation system and the gas measurement system and is used for fixing a concrete test piece, the concrete test piece has a set gradient, and a sensor group is arranged in the concrete test piece.

The cylinder body is divided into two cavities, namely a first cavity and a second cavity, the concrete test piece is arranged in the first cavity, meanwhile, a gas measurement system can be arranged in the first cavity, and an environment simulation system is arranged in the second cavity; in the actual use process of the concrete gas permeability test device, liquid and gas are injected into the second cavity through the gas-liquid injection port, the temperature and the pressure of water and gas in the second cavity are raised through the heating device, and after the environment reaches the expected temperature and pressure, the concrete gas permeability test is started; wherein, the detection component arranged in the second cavity can be used for monitoring corresponding indexes in the cavity, namely a temperature value, a humidity value and a pressure value; and the temperature of the heating device is reflected to the control system in real time, so that the opening and closing of the heating device are regulated, and the internal environmental condition of the test device is ensured to be stable. The gas measurement system detects the gas flow rate of the concrete test piece seeping out and the gas state transformation in the second cavity. After the test is completed, the water outlet is used for releasing pressure to the concrete gas permeability test device and discharging the residual water.

The traditional common gas permeability test device can only study the influence of unilateral factors on the gas permeability of concrete, and meanwhile, the test piece is limited in size, for example, the influence of temperature field or air pressure on the gas permeability is only studied, and the gas permeability of concrete coupled with various environmental factors cannot be studied. And during the test, as the test is carried out, water vapor liquefies, water droplets are generated on the upper surface of the concrete test piece, and the water droplets inhibit the speed of gas passing through the upper surface of the concrete, so that the test result is deviated.

The concrete gas permeability test device can provide accurate high-temperature, high-humidity and high-pressure test environments, and can perform gas permeability test and real-time monitoring of temperature field and moisture distribution under the coupling action of different high-temperature, high-humidity and high-pressure environmental conditions on a concrete test piece.

The invention designs a liquid meter for collecting water liquefied by water vapor on the upper surface of a concrete test piece; in order to enable the water drops to flow out better, the upper surface of the concrete test piece is made into an inclined plane with the gradient of 2-8%; the high-temperature-resistant adhesive is used for filling between the concrete test piece and the cylinder body, or a closed space is reserved between the concrete test piece and the cylinder wall, so that the precision requirement of the concrete test piece can be reduced, the dimensional deviation of large-volume concrete can occur in the pouring and curing processes, and the problem of uneven surface of the concrete test piece can be solved by the concrete gas permeability test device, and the test difficulty is greatly reduced.

2. The invention provides a concrete gas permeability test device, wherein a detection mechanism comprises a test piece temperature sensor, a resistivity sensor and a gas pressure sensor, and the test piece temperature sensor, the resistivity sensor and the gas pressure sensor are arranged in the concrete test piece in a staggered manner.

The temperature sensor, the resistivity sensor and the gas pressure sensor are pre-buried at different depths of the concrete test piece and used for measuring the temperature, the water content and the pore pressure at different depths of the test piece, and the output ends of the temperature sensor, the resistivity sensor and the gas pressure sensor are led out from the side face of the concrete test piece.

The summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the disclosure, nor is it intended to be used to limit the scope of the disclosure.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a combined gas permeability measuring device of a concrete gas permeability test device provided by the invention;

FIG. 2 is a schematic diagram showing a connection part of a first steel cylinder and a second steel cylinder of a combined gas permeability measuring device of a concrete gas permeability test device provided by the invention;

FIG. 3 is a top view of a first steel cylinder of a combined gas permeability test apparatus of the concrete gas permeability test apparatus provided by the invention;

fig. 4 is a schematic structural diagram of an adjustable environmental condition gas permeability measuring device of the concrete gas permeability test device provided by the invention.

Reference numerals illustrate:

1. a cylinder; 2. a fixing frame; 3. a first cavity; 4. a second cavity; 5. a test piece fixing system; 6. a water outlet; 7. a concrete test piece; 8. a sensor group; 9. a heat insulating member; 10. a support structure; 11. an environmental simulation system; 12. a gas-liquid injection port; 13. a heating device; 14. a cooling water circulation system; 15. a gas measurement system; 16. an ambient temperature sensor; 17. a humidity sensor; 18. an air pressure sensor; 19. a ceramic cushion block; 20. a temperature and humidity sensor; 21. a liquid meter; 22. a water tank; 23. a metering device; 24. a timing camera; 26. a first steel cylinder; 27. a second steel cylinder; 28. a circulating gas injection port; 29. a circulating gas outlet; 30. a gas outlet; 31. a liquid discharge port; 32. a sealing gasket; 33. a first sealing bolt; 34. a second sealing bolt; 35. a gas collection device; 36. sealing the rubber sleeve; 37. and (5) a bolt.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present disclosure. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present disclosure, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, or communicable with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art as the case may be.

In this disclosure, unless expressly stated or limited otherwise, a first feature being "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other by way of additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

The following disclosure provides many different embodiments, or examples, for implementing different structures of the disclosure. In order to simplify the present disclosure, components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present disclosure. Furthermore, the present disclosure may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings, it being understood that the preferred embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present disclosure.

Referring to fig. 1 to 4, the present invention provides a concrete gas permeability test apparatus, comprising: the environment simulation system 11 is arranged in the second cavity 4, and the environment simulation system 11 comprises a gas-liquid injection port 12, a detection component and a heating device 13; liquid and gas enter the second cavity 4 through the gas-liquid injection port 12, the heating device 13 is used for heating the liquid, and the detection component is used for detecting the temperature value, the humidity value and the pressure value in the second cavity 4; the gas measurement system 15 is arranged in the first cavity 3, and the gas measurement system 15 is used for measuring the volume of gas which permeates into the first cavity 3 from the gas in the second cavity 4 through the concrete test piece 7; the test piece fixing system 5 is arranged between the environment simulation system 11 and the gas measurement system 15 and is used for fixing a concrete test piece 7, the concrete test piece 7 has a set gradient, and a sensor group 8 is arranged in the concrete test piece.

The cylinder body 1 is divided into two cavities, namely a first cavity 3, a second cavity 4 and a concrete test piece 7, wherein the concrete test piece 7 is arranged in the first cavity 3, meanwhile, a gas measurement system 15 can be arranged in the first cavity 3, and an environment simulation system 11 can be arranged in the second cavity 4; in the actual use process of the concrete gas permeability test device, liquid and gas are injected into the second cavity 4 through the gas-liquid injection port 12, the temperature and the pressure of water and gas in the second cavity 4 are raised through the heating device 13, and after the environment reaches the expected temperature and pressure, the concrete gas permeability test is started; wherein, the detection component arranged in the second cavity 4 can be used for monitoring the corresponding indexes in the cavity, namely a temperature value, a humidity value and a pressure value; and reflects the temperature of the heating device 13 to the control system in real time, and accordingly, the opening and closing of the heating device 13 are adjusted, so that the stability of the internal environmental conditions of the test device is ensured. The gas measuring system 15 detects the gas flow rate of the concrete sample 7 permeated out and the gas state change inside the second cavity 4. After the test is completed, the water outlet 6 is used for releasing pressure to the concrete gas permeability test apparatus and discharging the remaining water.

The traditional common gas permeability test device can only study the influence of unilateral factors on the gas permeability of concrete, and meanwhile, the test piece is limited in size, for example, the influence of temperature field or air pressure on the gas permeability is only studied, and the gas permeability of concrete coupled with various environmental factors cannot be studied. And during the test, as the test proceeds, some water droplets are generated on the upper surface of the concrete test piece 7 due to the liquefaction of the water vapor, and these water droplets inhibit the rate of gas passing through the upper surface of the concrete, thereby causing deviation in the test results.

The concrete gas permeability test device can provide accurate high-temperature, high-humidity and high-pressure test environments, and can perform gas permeability test and real-time monitoring of temperature field and moisture distribution under the coupling action of different high-temperature, high-humidity and high-pressure environmental conditions on the concrete test piece 7.

The invention designs a liquid meter 21 for collecting water liquefied by water vapor on the upper surface of a concrete test piece 7; for better outflow of the water drops, the upper surface of the concrete test piece 7 is made into an inclined plane with the gradient of 2-8%; the high-temperature-resistant adhesive is used for filling between the concrete test piece 7 and the cylinder body 1, or a closed space is reserved between the concrete test piece 7 and the cylinder wall, so that the precision requirement of the concrete test piece 7 can be reduced, the dimensional deviation of mass concrete can occur in the pouring and curing process, and the problem of uneven surface of the concrete test piece 7 can be solved by the concrete gas permeability test device, so that the test difficulty is greatly reduced.

The specimen fixing system 5 is used for fixing a concrete specimen 7, the length of which coincides with the length of the concrete specimen 7.

The safety protection system comprises a steel wire mesh, an organic glass cover and a fuse, and is used for preventing accidents of the test and protecting the test from being carried out safely.

The steel wire mesh and the organic glass cover are adopted to enclose the concrete gas permeability test device, so that the gas leakage phenomenon is prevented in the test process, and the high-temperature and high-pressure gas inside the cylinder 1 is prevented from burning test personnel;

the setting of fuse can play the effect of overcurrent protection, prevents that the interior gas temperature of environmental simulation system 11 from being too high, when the temperature exceeded the alarm value, the fuse fast-fusing cuts off the circuit, increases experimental security.

In some alternative embodiments, the concrete gas permeability test apparatus comprises a combined gas permeability test apparatus, or two implementations of an adjustable environmental condition gas permeability measurement apparatus.

In some alternative embodiments, the detection components of the environmental simulation system 11 include an ambient temperature sensor 16 and a humidity sensor 17, and a barometric pressure sensor 18, the ambient temperature sensor 16 for detecting a temperature value within the second cavity 4, the humidity sensor 17 for detecting a humidity value within the second cavity 4, the barometric pressure sensor 18 for detecting a pressure value within the second cavity 4; the environment simulation system 11 further comprises a ceramic cushion block 19, and the heating device 13 is arranged on the ceramic cushion block 19. Namely, the environmental temperature sensor 16, the humidity sensor 17 and the air pressure sensor 18 which are arranged in the second cavity 4 are all used for monitoring corresponding indexes in the cavity and reflecting the indexes in the control system in real time, and accordingly, the opening and closing of the heating device 13 are adjusted, so that the internal environmental condition of the test device is ensured to be stable.

In some alternative embodiments, the environmental simulation system 11 further includes a ceramic block 19, and the heating device 13 is disposed on the ceramic block 19. The heating means 13 is prevented from coming into direct contact with the thermal insulation coating, resulting in burning out of the insulation material.

In some alternative embodiments, the cartridge 1 comprises: the cylinder body 1 is arranged on the fixed frame 2 and comprises a first steel cylinder 26 and a second steel cylinder 27, a first cavity 3 is formed in the first steel cylinder 26, and a second cavity 4 is formed in the second steel cylinder 27; a supporting structure 10 is arranged between the first steel cylinder 26 and the second steel cylinder 27, and the supporting structure 10 is used for supporting the concrete test piece 7; and the heat insulation member 9 is arranged on the outer wall of the cylinder body 1.

The concrete test piece device further comprises a sealing structure, wherein the sealing structure is arranged between the first cavity 3 and the second cavity 4 and is used for sealing the concrete test piece 7, the first cavity 3 and the second cavity 4.

The sealing structure comprises a sealing gasket 32, a first sealing bolt 33 and a second sealing bolt 34;

the first steel cylinder 26 is formed by splicing two semicircular cylinders, and the two semicircular cylinders are tightly pressed against a sealing gasket 32 between flanges through a first sealing bolt 33 to realize sealing; the first steel cylinder 26 and the second steel cylinder 27 are pressed against the sealing gasket 32 by the second sealing bolt 34 to realize sealing.

And the concrete test piece 7 and the first steel cylinder 26 are sealed by high-temperature-resistant adhesive.

The supporting structure 10 is a supporting cushion block arranged on the inner wall of the cylinder body 1. The supporting cushion block is used for fixing the concrete test piece 7 so as to prevent the concrete test piece 7 from sliding down.

Wherein, the supporting cushion lower part is equipped with a plurality of support columns, prevents that the supporting cushion from taking place deformation in the test process.

The fixing frame 2 is arranged on the ground, and two circular rings (not shown in the figure) are arranged above and below the fixing frame 2 and are used for fixing the concrete gas permeability test device; the periphery of the two circular rings is wrapped by a heat insulating piece 9, and the inner wall of the cylinder body 1 is coated with a uniform heat insulating coating to prevent the concrete gas permeability test device from heat exchange with the outside;

in some alternative embodiments, the gas measurement system 15 of the combined gas permeability test apparatus includes: a temperature and humidity sensor 20 disposed in the first cavity 3; a liquid meter 21 penetrating the cylinder 1 and extending into the first cavity 3, the liquid meter 21 being configured to detect a volume of liquid in the first cavity 3; the water tank 22 penetrates through the cylinder 1 and extends into the first cavity 3, and the water tank 22 is used for detecting one end, far away from the concrete test piece 7, of the first cavity 3; a metering device 23 connected to the water tank 22;

the temperature and humidity sensor 20 can reflect the temperature and humidity changes in the first cavity 3 in real time, and the liquid meter 21 is used for testing the volume of the water liquefied by the water vapor in the first cavity 3;

the water tank 22 and the metering device 23 form a gas permeation quantity testing device for measuring the gas permeation quantity at the upper end of the concrete test piece 7. Wherein the metering device 23 is covered with a nonwoven fabric in order to prevent moisture in the metering device 23 from evaporating out, which leads to inaccurate test results.

The gas seeping from the concrete sample 7 is discharged from the gas outlet 30 and is introduced into the special water tank 22, the gas pressure can cause the water to be discharged into the metering device 23, and the volume of the discharged water is the volume of the discharged gas. The slope of the non-heated surface of the concrete test piece 7 is reserved for 2-8%, so that water on the surface of the concrete test piece 7 is led out into the liquid meter 21 through the liquid outlet 31.

The gas measurement system 15 further comprises a timing camera 24, the timing camera 24 being used for timing the recording of the amount of water in the liquid meter 21 and the metering device 23. The metering device 23 is provided with a timing camera 24 on the scale side, and the gas and liquid volumes in the gas-liquid permeation quantity testing device are recorded by timing photographing.

In some alternative embodiments, the gas measuring system 15 of the adjustable environmental condition type gas permeability measuring device comprises a gas collecting device 35 and a sealing rubber sleeve 36, wherein the gas collecting device 35 is sleeved on the top of the concrete sample 7, and the sealing rubber sleeve 36 is used for the first cavity 3.

The cylinder body 1 is internally provided with a bolt 37, the bolt 37 is used for propping up the upper surface of the concrete test piece 7, the concrete test piece 7 is pressed downwards, the concrete test piece 7 is tightly buckled on the supporting cushion block, a sealing gasket 32 is arranged between the bottom surface of the concrete test piece 7 and the supporting cushion block, and the tightness between the bottom surface of the test piece and the supporting cushion block is ensured.

The gas measuring system 15 is composed of a gas collecting device 35 and a sealing gum cover 36. The gas collecting device 35 is a latex balloon sleeved on the top of the concrete test piece 7 and is used for collecting gas permeated from the environment simulation system 11 through the concrete test piece 7.

The sealing rubber sleeve 36 is used for ensuring the air tightness between the air collecting device 35 and the concrete test piece 7 on one hand, and can enable the side surface environment of the concrete test piece 7 to be a closed space on the other hand, so that the environmental condition of the concrete test piece 7 can be adjusted more easily.

In some optional embodiments, the concrete gas permeability test device further comprises a safety protection system, wherein the safety protection system comprises a steel wire mesh, an organic glass cover and a fuse, the steel wire mesh and the organic glass cover are arranged on the periphery of the device, so that a gas leakage phenomenon is prevented in the test process, and the inside high-temperature high-pressure gas burns test personnel; the heating device 13 is provided with fuses in the respective circuits.

Through setting up barrel 1 at safety protection system, can utilize safety protection system to fix barrel 1, guaranteed the experimental stability of barrel 1.

In some alternative embodiments, the combined gas permeability test apparatus further comprises a cooling water circulation system 14 provided on the outer wall of the cylinder 1, the cooling water circulation system 14 being used for cooling the cylinder 1.

The cooling water circulation system 14 is located at the bottom of the cylinder 1, and is used for cooling the cylinder 1, so that the over-high temperature of the cylinder 1 is prevented, and the test is prevented from being influenced. And monitoring the gas flow rate of the test piece permeation by using a gas collection system.

In some alternative embodiments, the adjustable environmental condition gas permeability measurement device further comprises a circulating gas injection port 28 and a circulating gas discharge port 29, the circulating gas injection port 28 and the circulating gas discharge port 29 being provided on the cavity wall of the second cavity 4.

The circulating gas inlet 28 and the circulating gas outlet 29 can adjust the side environmental conditions of the concrete sample 7 in the second cavity 4 to make the concrete sample stable in a certain temperature range.

In some alternative embodiments, the sensor set 8 includes a specimen temperature sensor and a resistivity sensor, and a gas pressure sensor, which are staggered within the concrete specimen 7.

The temperature sensor, the resistivity sensor and the gas pressure sensor are pre-buried at different depths of the concrete test piece 7 and used for measuring the temperature, the water content and the pore pressure at different depths of the test piece, and the output ends of the temperature sensor, the resistivity sensor and the gas pressure sensor are led out from the side face of the concrete test piece 7.

To prevent gas permeation along the interface between the sensor line and the concrete time during the test, 1-5 ellipsoid materials were placed on the sensor line and the cross-sectional area was increased.

The invention also provides a working method of the concrete gas permeability test device, which comprises the following steps:

coating high-temperature resistant resin on the side surface of the prepared concrete test piece 7 to ensure the tightness of the side surface of the concrete test piece 7, and opening an upper steel cylinder for fixing the concrete test piece 7 into two semicircular cylinders after the resin is solidified; placing the semicircular cylinder on the horizontal ground, and coating a heat-insulating coating with proper thickness and high-temperature-resistant adhesive on the surface;

then, placing the concrete test piece 7 into one of the semi-cylindrical drums, fixing, covering the other semi-cylindrical drum on the concrete test piece 7, and tightening a second sealing bolt 34 to ensure the sealing of the device;

the environment simulation system 11 is connected with the cylinder 1 through a second sealing bolt 34, and the concrete test piece 7 is fixed on the supporting cushion block; the circuit is connected, the power is supplied, whether the environment simulation system 11, the gas measuring system 15 and the like can normally operate or not is checked, then the gas-liquid injection port 12 is opened, a nitrogen bottle is connected, nitrogen is injected into the second cavity 4, and whether the air tightness of the device is good or not is confirmed by observing the indication of the air pressure sensor 18;

after the air tightness is determined to be good, the heat insulation 9 is wrapped on the outer wall of the cylinder body 1 and is arranged on the fixing frame 2;

adding a proper amount of liquid into the environment simulation system 11 from the gas-liquid injection port 12, closing the gas-liquid injection port 12, opening the heating device 13 to heat the water in the second cavity 4, and monitoring the gas state change through the environment temperature sensor 16, the humidity sensor 17 and the air pressure sensor 18;

the cooling water circulation system 14 was turned on and the cooling treatment was continued for the first steel cylinder 26 during the test. After reaching the preset test working condition, the heating device 13 of the environment simulation system 11 is changed from continuous heating to intermittent heating so as to maintain the internal environment condition of the first steel cylinder 26 stable;

starting a data recorder to collect data of the detection mechanism 8 in the concrete test piece 7, opening a timing camera 24, and taking a picture to record water quantities in the liquid meter 21 and the metering device 23 at fixed time, wherein the gas quantity oozing out of the concrete test piece 7 is obtained by a drainage method;

after all the steps are prepared, the appearance test is carried out on the steel wire mesh and the organic glass cover, so that emergency is avoided;

if the environmental simulation system fails, the fuse in the heating device 13 is destroyed and the heating is stopped due to the excessive gas pressure and the excessive temperature in the second steel cylinder 27. The cylinder 1 is cooled according to the actual conditions, so that the test safety is ensured.

After 72h, the heating device 13 and the timing camera 24 are closed, data acquisition is stopped, the heat insulation piece 9 outside the cylinder 1 is removed, then the cylinder 1 is cooled, the water outlet 6 is opened after the device is cooled to a proper temperature, the air pressure inside and outside the device is balanced, and redundant water is discharged.

The first sealing bolt 33 and the second sealing bolt 34 are unscrewed, the concrete test piece 7 which is subjected to the permeability test is immediately taken out of the device, covered by plastic cloth, and the humidity change of the concrete test piece is avoided for subsequent test study.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims

1. A concrete gas permeability test apparatus, comprising:

the environment simulation system (11) is arranged in the second cavity (4), and the environment simulation system (11) comprises a gas-liquid injection port (12), a detection assembly and a heating device (13); liquid and gas enter the second cavity (4) through the gas-liquid injection port (12), the heating device (13) is used for heating the liquid, and the detection component is used for detecting the temperature value, the humidity value and the pressure value in the second cavity (4);

the gas measurement system (15) is arranged in the first cavity (3), and the gas measurement system (15) is used for measuring the volume of gas which permeates into the first cavity (3) from the gas in the second cavity (4) through the concrete test piece (7);

the test piece fixing system (5) is arranged between the environment simulation system (11) and the gas measurement system (15) and is used for fixing a concrete test piece (7), the concrete test piece (7) has a set gradient, and a sensor group (8) is arranged in the concrete test piece.

2. The concrete gas permeability test apparatus according to claim 1, comprising two implementations of a combined gas permeability test apparatus or an adjustable environmental condition gas permeability measurement apparatus.

3. The concrete gas permeability test apparatus according to claim 1, wherein the detection assembly of the environment simulation system (11) includes an environment temperature sensor (16) and a humidity sensor (17), and a gas pressure sensor (18), the environment temperature sensor (16) being configured to detect a temperature value in the second cavity (4), the humidity sensor (17) being configured to detect a humidity value in the second cavity (4), the gas pressure sensor (18) being configured to detect a pressure value in the second cavity (4); the environment simulation system (11) further comprises a ceramic cushion block (19), and the heating device (13) is arranged on the ceramic cushion block (19).

4. The concrete gas permeability test apparatus according to claim 1, comprising:

the cylinder body (1) is arranged on the fixing frame (2), the cylinder body (1) comprises a first steel cylinder (26) and a second steel cylinder (27), a first cavity (3) is formed in the first steel cylinder (26), and a second cavity (4) is formed in the second steel cylinder (27); a supporting structure (10) is arranged between the first steel cylinder (26) and the second steel cylinder (27), and the supporting structure (10) is used for supporting a concrete test piece (7); a heat insulating member (9) provided on the outer wall of the cylinder (1);

the sealing structure is arranged between the first cavity (3) and the second cavity (4) and is used for sealing the concrete test piece (7), the first cavity (3) and the second cavity (4).

5. The concrete gas permeability test apparatus according to claim 2, wherein the gas measurement system (15) of the combined gas permeability test apparatus comprises: the temperature and humidity sensor (17) is arranged in the first cavity (3); a liquid meter (21) penetrating the cylinder (1) and extending into the first cavity (3), the liquid meter (21) being configured to detect the volume of liquid in the first cavity (3); the water tank (22) penetrates through the cylinder body (1) and stretches into the first cavity (3), and the water tank (22) is used for detecting one end, far away from the concrete test piece (7), of the first cavity (3); a metering device (23) connected with the water tank (22); the gas measurement system (15) further comprises a timing camera (24), the timing camera (24) being used for timing recording of the amount of water in the liquid meter (21) and the metering device (23).

6. The concrete gas permeability test apparatus according to claim 2, characterized in that the gas measuring system (15) of the adjustable environmental condition type gas permeability measuring apparatus comprises a gas collecting device (35) and a sealing gum cover (36), the gas collecting device (35) is sleeved on top of the concrete test piece (7), and the sealing gum cover (36) is used for the first cavity (3).

7. The concrete gas permeability test apparatus according to claim 1, wherein: the concrete gas permeability test device further comprises a safety protection system, wherein the safety protection system comprises a steel wire mesh, an organic glass cover and a fuse, the steel wire mesh and the organic glass cover are arranged on the periphery of the device, so that the gas leakage phenomenon in the test process is prevented, and the inside high-temperature high-pressure gas burns test personnel; a fuse is provided in each circuit of the heating device (13).

8. The concrete gas permeability test apparatus according to claim 2, wherein the combined gas permeability test apparatus further comprises a cooling water circulation system (14) provided on an outer wall of the cylinder (1), the cooling water circulation system (14) being for cooling the cylinder (1).

9. The concrete gas permeability test apparatus according to claim 2, wherein the adjustable environmental condition type gas permeability measurement apparatus further comprises a circulating gas injection port (28) and a circulating gas discharge port (29), the circulating gas injection port (28) and the circulating gas discharge port (29) being provided on a wall of the second cavity (4).

10. The concrete gas permeability test apparatus according to claim 1, wherein the sensor group (8) includes a specimen temperature sensor and a resistivity sensor, and a gas pressure sensor, the specimen temperature sensor and the resistivity sensor, and the gas pressure sensor being unevenly disposed in the concrete test piece.