CN103471953A - Automatic test system and test method for testing surface capillary water absorption of concrete - Google Patents

Abstract

The invention provides an automatic test system and test method for testing surface capillary water absorption of concrete, relates to a test system and a test method thereof, and aims to solve the problems that the existing test system is impracticable to ensure that the effective depth of a specimen immersed in water is always a small constant value, the water absorption mass of the specimen can not be automatically and continuously measured in real time, accidental errors caused by manual operation and the like exist, the test sensitivity is low and the precision is low. The system comprises a constant-pressure water supply unit, an electronic balance and a specimen water absorption unit. The test method comprises the following steps: 1, emptying liquid in a balanced air inlet pipe; 2, regulating height and water level of the specimen water absorption unit; and 3, acquiring mass data by using a computer. According to the invention, the effective depth of the specimen immersed in water can be ensured to be always a small constant value, real-time automatic continuous measurement can be realized, the accidental errors can be reduced, the test sensitivity is high, and the precision is high. The system and method are used in the fields of experimental study on pore structures and surface capillary water absorption of a concrete material, and physical engineering durability detection.

Description

An automatic test system and test method for concrete surface capillary water absorption

technical field

The invention relates to a test system and a test method thereof, in particular to an automatic test system and a test method for capillary water absorption of concrete surface.

Background technique

The durability of concrete materials is of great significance to the safety and economy of the whole life cycle of concrete structures. How to correctly evaluate and detect the durability of concrete materials is very important for the engineering application of concrete materials. The durability of concrete is closely related to the speed at which aggressive media migrate through the pores and cracks inside the material. Capillary water absorption can quantitatively describe the ease or speed of water absorption by concrete materials under capillary action, and there is a clear and strict theoretical relationship with water diffusivity and permeability. It is an important indicator for quantitatively characterizing the durability of concrete materials. index. Compared with the test of concrete gas, moisture and chloride ion permeability and other indicators, the surface capillary water absorption rate is used to evaluate the material transmission performance and durability of concrete materials by measuring the speed of water absorption per unit area of concrete specimens over time. , the test principle is simple and is especially suitable for characterizing the quality of surface concrete, which is directly and closely related to durability, and is widely used in academia and engineering.

The surface capillary water absorption test requires monitoring the mass change of the side-sealed specimen when the surface is in contact with water, and the actual measurement is often directly calculated by manually measuring the mass change of the concrete specimen. At this time, with the progress of capillary water absorption on the surface, it is difficult to ensure that the depth of the concrete specimen immersed in water is always a small value during the entire measurement process. Secondly, due to the high density and mass of concrete specimens and the relatively small water absorption mass, when directly testing the quality of water-absorbing concrete specimens, it is also required to dry the free water on the surface of the specimens in contact with water with a damp cloth, which makes the water absorption quality difficult to determine. The measurement accuracy is low and it is easily affected by manual operation error. In addition, manual measurement of the mass of water-absorbing concrete specimens will inevitably take a certain amount of time, and the timing cannot be stopped during the quality test. During this period, the hydraulic boundary conditions on the surface of the concrete specimens are changed, which will make the surface contact with free water and act on the capillary driving force. The entire process of drawing water into the interior of the material is disturbed. The above-mentioned various influencing factors make the measurement results of surface capillary water absorption may introduce large errors, and it is difficult to monitor continuously for a long time. In 1998, Sabir proposed to use a suspended electronic balance to directly measure the mass change of the water-absorbing concrete specimen to convert the capillary water absorption rate. Although the manual operation error caused by manually drying the contact surface between the specimen and water can be avoided, the system is tested. It still cannot guarantee that the depth of the test piece submerged in water is always constant to a small value. In 2006, Cerny proposed to use a Martens bottle device to maintain a constant water level. He made some improvements on the basis of Sabir's test device, but it is the same as the device proposed by Sabir by measuring the mass change of a concrete specimen with a large density and mass. Calculating the water absorption quality, because the mass change caused by capillary water absorption is very small and the sensitivity of the traditional Malovich bottle (the sensitivity of the water level change to be measured is about 0.5mm) cannot meet the requirements, making it difficult to guarantee the measurement accuracy of the concrete capillary water absorption quality, which is very important for long-term testing. Changes in the quality of water absorption are particularly disadvantageous.

Contents of the invention

The purpose of the present invention is to solve the problem that the existing surface capillary water absorption test system is difficult to ensure that the effective depth of the concrete specimen immersed in water is always a small value, and the water absorption quality of the concrete specimen cannot be measured in real time, automatically and continuously, and there are In order to solve the problems of accidental error, low test sensitivity and low precision introduced by manual operation, an automatic test system and test method for concrete surface capillary water absorption are provided.

A concrete surface capillary water absorption automatic testing system of the present invention is composed of a constant pressure water supply unit, an electronic balance and a test piece water absorption unit, and the constant pressure water supply unit and the test piece water absorption unit are connected through a water outlet pipe, a silicone hose and a water inlet pipe;

The constant pressure water supply unit is composed of a constant pressure water supply sealed bottle, a gas connecting pipe, a balance inlet pipe and a water outlet pipe; the electronic balance is arranged at the bottom of the constant pressure water supply sealed bottle and is used to measure the weight of the constant pressure water supply unit; Among them, the gas connecting pipe and the balanced air inlet pipe are both arranged on the upper end of the constant pressure water supply sealed bottle, and the end of the gas connected pipe inside the constant pressure water sealed bottle is arranged near the upper end of the constant pressure water fed sealed bottle, and the balanced air inlet pipe is placed on the constant pressure water supply sealed bottle. One end inside the sealed bottle is set near the lower end of the constant pressure water supply sealed bottle; a gas valve is arranged on the upper part of the gas communication pipe; a gas valve is arranged on the upper part of the balanced air inlet pipe; a needle tube is arranged at the bottom of the balanced air inlet pipe; the outlet pipe with valve One end communicates with the bottom side end of the constant pressure water supply seal bottle, and the other end communicates with the water inlet pipe through a silicone hose, and the water inlet pipe communicates with the bottom side of the sample sealing chamber;

The sample water absorption unit is composed of a sample sealing chamber, a water inlet pipe, a drain valve, a regulating valve, an L-shaped water level gauge and a sample support; wherein, a level is arranged on the upper part of the sample sealing chamber, and an inlet is arranged on the lower end. For the water pipe, an L-shaped water level gauge is installed at the lower end of the right side of the sealed chamber, and the other end of the L-shaped water level gauge is set upward; a regulating valve is installed at the upper right end of the sample sealed chamber; Three equal-height sample supports are arranged on the inner side of the bottom of the sealed chamber.

The test method of a kind of concrete surface capillary water absorption automatic test system of the present invention is as follows:

1. Close the valve on the water outlet pipe, seal the bottled water to the constant pressure water supply until it does not submerge the lower end of the gas connection pipe; open the gas valve on the gas connection pipe and the gas valve on the balance inlet pipe and seal the constant pressure water supply seal bottle , and then close the gas valve on the upper part of the gas communication pipe; open the valve on the water outlet pipe, the water inside the constant pressure water supply sealed bottle flows out through the water outlet pipe, the water level in the constant pressure water supply sealed bottle drops slightly, and the air pressure in the internal cavity drops slightly and balances The water level in the intake pipe drops rapidly. When the water level drops to the lower end of the balanced intake pipe and the gas begins to enter the constant pressure water supply seal bottle through the balanced intake pipe, close the valve on the water outlet pipe to empty the liquid in the balanced intake pipe. The liquid inside the constant pressure water supply sealed bottle is in a balanced state;

2. Use a silicone hose to connect the outlet pipe with the water inlet pipe, close the drain valve, open the regulating valve, add water to the sample sealing chamber to submerge the water inlet pipe and the communication hole between the L-shaped water level gauge and the sample sealing chamber, and at the same time require the water level Submerge the top of the sample support by 3mm, cover and seal the top cover of the sample sealing chamber; adjust the height adjustment feet to change the height of the sample sealing bottle to make the internal liquid level 10~ 15mm, open the valve on the water outlet pipe, the water in the constant pressure water supply sealed bottle begins to replenish the sample sealed chamber and empty the gas that may exist in the silicone hose, close the regulating valve, the water level in the sample sealed chamber remains unchanged, L The water level in the L-shaped water level gauge continues to rise and may overflow; adjust the height adjustment foot so that the gas no longer enters the constant pressure water supply seal bottle through the balance inlet pipe and the corresponding equilibrium water level in the L-shaped water level gauge is lower than the top of the L-shaped water level gauge At the same time, the level of the water-absorbing unit of the test piece is controlled by a spirit level; the height of the water-absorbing unit of the test piece and the water level are adjusted, and the whole system is in a state of water level balance; at this time, if a small amount of water is sucked from the top of the L-shaped water level gauge, the gas will enter through the balanced air intake pipe Constant pressure feed water to seal the bottle, and make the whole system in a balanced state again;

3. Close the valve on the water outlet pipe, open the regulating valve, open the upper cover of the sample sealing chamber, lower the water level of the sample sealing chamber through the drain valve and make the tip of the sample support part exposed to the water surface; Put the test piece on the upper part of the support piece of the test piece and temporarily do not contact with water, cover the upper cover of the sample sealing chamber and seal it well; open the valve on the water outlet pipe, water starts to replenish from the constant pressure water supply sealing bottle to the sample sealing chamber, The gas enters the constant pressure water supply sealed bottle through the balance inlet pipe, and the water level in the sample sealed chamber gradually rises. When the internal water level submerges the test piece to a height of 3mm, close the regulating valve, and the water level in the sample sealed chamber remains unchanged and the L-shaped water level The water level in the meter continues to rise until it is 1mm from the top and reaches a balanced state, allowing the computer to start collecting quality data of the constant pressure water supply unit at a preset time interval. As the concrete specimen absorbs water, the air pressure in the sample sealing chamber drops slightly, water continues to be replenished from the constant pressure water supply sealing bottle to the sample sealing chamber, the pressure of the gas cavity in the upper part of the constant pressure water supply sealing bottle drops, and the external atmosphere flows into the sample sealing chamber through the balanced air inlet pipe. Constant pressure feeds water to the inside of the sealed bottle to replenish and reach a new equilibrium state. After balancing, the liquid level in the L-shaped water level gauge remains unchanged, and the effective depth corresponding to the bottom surface of the test piece submerged in water is constant. The mass of water absorbed by the test piece is equal to the reduction in the mass of the constant pressure water supply unit and can be measured by the electronic balance. Computer The mass decrease of the collection electronic balance is equal to the increase of the concrete specimen mass, and the surface capillary water absorption of the concrete specimen can be calculated through the mass change.

The present invention comprises following beneficial effect:

1. Since the constant pressure water supply unit and the specimen water absorption unit are connected through a silicone hose, the constant pressure water supply unit can strictly ensure that the liquid level of the L-shaped water level gauge is constant, thereby ensuring that the bottom of the concrete specimen is immersed in water effectively. The depth is a constant minimum value, which strictly meets the hydraulic boundary conditions required by the surface capillary water absorption test, and can avoid affecting the measurement accuracy due to the evaporation of water in the sample sealing chamber during long-term testing;

The present invention adopts a sample sealing chamber with a regulating valve, which can not only ensure that the effective depth of the bottom surface of the test piece immersed in water is constant at a small value, but also avoid the impact of water evaporation in the sample sealing chamber on the measurement accuracy during long-term testing. The L-type The water level gauge and the sample sealing chamber can greatly improve the sensitivity of the test system. When the sample absorbs about 0.5g of water in the present invention, the balance inlet pipe will start to replenish air, and the water level in the corresponding sealing chamber will change by about 0.02mm. The existence of the liquid surface can adaptively adjust the curvature of the liquid surface, and the measurement accuracy of the actual water absorption quality is higher; while the sensitivity of the traditional Martens bottle to the change of the measured water level is about 0.5mm;

2. Since the constant pressure water supply unit and the specimen water absorption unit are connected through a silicone hose, the moisture absorbed by the concrete specimen can be replenished from the constant pressure water supply unit in real time and continuously, and the water absorption of the concrete specimen is equal to constant The reduction of the mass of the pressure water supply unit, through the indirect measurement of the reduction of the mass of the constant pressure water supply unit, can measure the water absorption of the concrete specimen in real time. Water absorption test requirements;

3. Since the water absorption quality of the concrete specimen is monitored by indirect measurement of the quality change of the constant pressure water supply unit, it can reduce the accidental water caused by manual drying of the free water at the bottom of the concrete specimen, and the free water at the bottom of the specimen for a period of time. error;

4. Because the electronic balance is used to measure the quality change of the constant pressure water supply unit to indirectly measure the water absorption quality of the concrete specimen, real-time, continuous, fully automatic and long-term tracking measurement can be achieved, and it can be used to measure and study concrete materials for a long time Mass change of surface water absorption and its surface capillary water absorption. The invention can strictly meet the hydraulic boundary condition that the effective depth of the concrete specimen submerged in water is constant to a small value required by the surface capillary water absorption test, and can perform real-time, fully automatic and long-term continuous testing with high precision and excellent test results. With good reproducibility and convenient test operation, it can be applied to the experimental research of concrete material pore (crack) structure, surface capillary water absorption and actual engineering durability testing.

Description of drawings

Fig. 1 is the structure schematic diagram of automatic measurement system of surface capillary water absorption;

Fig. 2 is a test result graph of concrete surface capillary water absorption in Example 1, wherein · represents the measured data, — represents the fitting curve.

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific embodiment one: a kind of concrete surface capillary water absorption automatic test system of this embodiment is made up of constant pressure water supply unit, electronic balance 2 and test piece water absorption unit, constant pressure water supply unit and test piece water absorption unit pass water outlet pipe 7, silica gel The hose 8 communicates with the water inlet pipe 9;

The constant pressure water supply unit is composed of a constant pressure water supply sealed bottle 1, a gas communication pipe 5, a balance inlet pipe 6 and a water outlet pipe 7; the electronic balance 2 is arranged at the bottom of the constant pressure water supply sealed bottle 1 and is used to measure the The weight of the pressure water supply unit; wherein, the gas communication pipe 5 and the balance air intake pipe 6 are all arranged on the upper end of the constant pressure water supply sealed bottle 1, and the end of the gas communication pipe 5 inside the constant pressure water supply sealed bottle 1 is arranged near the constant pressure water supply seal On the upper end of the bottle 1, one end of the balanced air intake pipe 6 inside the constant pressure water supply sealed bottle 1 is arranged near the lower end of the constant pressure water supply sealed bottle 1; the upper part of the gas communication pipe 5 is provided with a gas valve 14; the upper part of the balanced air intake pipe 6 is provided with A gas valve 15; a needle tube is arranged at the bottom of the balance inlet pipe 6; one end of the water outlet pipe 7 with the valve 16 communicates with the side end of the bottom of the constant pressure water supply sealing bottle 1, and the other end communicates with the water inlet pipe 9 through the silicone hose 8. The water inlet pipe 9 communicates with the bottom side of the sample sealing chamber 3;

The sample water absorption unit is composed of a sample sealing chamber 3, a water inlet pipe 9, a drain valve 10, a regulating valve 11, an L-shaped water level gauge 12 and a sample support member 13; wherein, the upper part of the sample sealing chamber 3 is provided with a A level 18 is provided with a water inlet pipe 9 at the lower end, an L-shaped water level gauge 12 is arranged at the lower end of the right side of the sealed chamber 3, and the other end of the L-shaped water level gauge 12 is set upward; a regulating valve 11 is arranged at the upper right side of the sample sealed chamber 3 The drain valve 10 is set at the bottom of the sample sealing chamber 3; the inside of the bottom of the sample sealing chamber 3 is provided with three sample supports 13 of equal height.

The beneficial effect of this implementation mode:

1. Since the constant pressure water supply unit and the specimen water absorption unit are connected through a silicone hose, the constant pressure water supply unit can strictly ensure that the liquid level of the L-shaped water level gauge is constant, thereby ensuring that the bottom of the concrete specimen is immersed in water effectively. The depth is a constant minimum value, which strictly meets the hydraulic boundary conditions required by the surface capillary water absorption test, and can avoid affecting the measurement accuracy due to the evaporation of water in the sample sealing chamber during long-term testing;

In this embodiment, the sample sealing chamber is used with a regulating valve, which not only ensures that the effective depth of the bottom surface of the test piece immersed in water is kept at a small value, but also avoids the influence of water evaporation in the sample sealing chamber on the measurement accuracy during long-term testing. The combination of a water level gauge with a sample sealing chamber can greatly improve the sensitivity of the test system. In this embodiment, when the sample absorbs about 0.5g of water, the balance inlet pipe will start to replenish air, and the water level in the corresponding sealing chamber will change by about 0.02mm. The existence of the meniscus can adaptively adjust the curvature of the liquid surface, and the measurement accuracy of the actual water absorption quality is higher; while the sensitivity of the traditional Martens bottle to the change of the measured water level is about 0.5mm;

2. Since the constant pressure water supply unit and the specimen water absorption unit are connected through a silicone hose, the moisture absorbed by the concrete specimen can be replenished from the constant pressure water supply unit in real time and continuously, and the water absorption of the concrete specimen is equal to constant The reduction of the mass of the pressure water supply unit, through the indirect measurement of the reduction of the mass of the constant pressure water supply unit, can measure the water absorption of the concrete specimen in real time. Water absorption test requirements.

Embodiment 2: This embodiment differs from Embodiment 1 in that: the specimen water absorption unit also includes height adjustment feet 17 and a level 18 . Others are the same as in the first embodiment.

Embodiment 3: This embodiment differs from Embodiment 1 or Embodiment 2 in that three equal-height height-adjusting feet 17 are arranged outside the sample sealing chamber 3 and are located on a horizontal operating platform 19 . Others are the same as in the first or second embodiment.

Embodiment 4: This embodiment differs from Embodiments 1 to 3 in that: the electronic balance 2 has a measuring range of 1000 g and an accuracy of 0.001 g. Others are the same as those in the first to third specific embodiments.

Embodiment 5: This embodiment is different from Embodiment 1 to Embodiment 4 in that: the gas communication pipe 5, the balance inlet pipe 6, the water outlet pipe 7, the water inlet pipe 9 and the L-shaped water level gauge 12 are made of plexiglass . Others are the same as one of the specific embodiments 1 to 4.

Embodiment 6: This embodiment differs from Embodiment 1 to Embodiment 5 in that: the vertical distance between the top of the L-shaped water level gauge 12 and the top of the sample support 13 is 5 mm. Others are the same as one of the specific embodiments 1 to 5.

Specific implementation mode seven: the present embodiment is a test method of a concrete surface capillary water absorption automatic test system, and its test method comprises the following steps:

1. Close the valve 16 on the water outlet pipe 7, fill the constant pressure water supply sealed bottle 1 with water until it does not submerge the lower end of the gas communication pipe 5; open the gas valve 14 on the gas communication pipe 5 and the gas valve on the balance inlet pipe 6 15 and seal the constant pressure water supply sealing bottle 1, then close the gas valve 14 on the upper part of the gas communication pipe 5; open the valve 16 on the water outlet pipe 7, the water inside the constant pressure water supply sealing bottle 1 flows out through the water outlet pipe 7, and the constant pressure water supply The water level in the sealed bottle 1 drops slightly, the air pressure in the inner cavity drops slightly, and the water level in the balanced air intake pipe 6 drops quickly. When the water level drops to the lower end of the balanced air intake pipe 6 and the gas begins to enter the constant pressure water supply through the balanced air intake pipe 6 When the bottle 1 is sealed, the valve 16 on the water outlet pipe 7 is closed, and the liquid in the balanced intake pipe is emptied, and the liquid inside the sealed bottle 1 is in a balanced state for constant pressure water supply;

2. Use a silicone hose 8 to connect the outlet pipe 7 with the water inlet pipe 9, close the drain valve 10, open the regulating valve 11, add water to the sample sealing chamber 3 until the water inlet pipe 9 and the L-shaped water level gauge 12 and the sample are submerged The connecting hole of the sealing chamber 3 requires the water level to submerge the top 3mm of the sample support member 13, cover the top cover of the sample sealing chamber 3 and seal it well; adjust the height adjustment foot 17 to change the height of the test piece sealing bottle 3 to The internal liquid level is 10-15mm lower than the needle tip level of the balance inlet pipe 6, and the valve 16 on the outlet pipe 7 is opened, and the water in the constant pressure water supply sealing bottle 1 starts to replenish and empty the silicone hose in the sample sealing chamber 3 8, close the regulating valve 11, the water level in the sample sealing chamber 3 remains unchanged, and the water level in the L-shaped water level gauge 12 continues to rise and may overflow; adjust the height regulating foot 17 so that the gas no longer enters through the balance. The trachea 6 enters the constant pressure water supply sealed bottle 1 and the corresponding equilibrium water level in the L-shaped water level gauge 12 is 1 mm lower than the top of the L-shaped water level gauge. At the same time, the level of the water absorption unit of the test piece is controlled by the level gauge 18; the height and water level of the water absorption unit of the test piece are adjusted Finished, the whole system is in the state of water level balance; at this time, if a small amount of water is sucked from the top of the L-shaped water level gauge, the gas will enter the constant pressure water supply seal bottle 1 through the balance inlet pipe 6, and the whole system will be in a balanced state again;

3. Close the valve 16 on the outlet pipe 7, open the regulating valve 11, open the upper cover of the sample sealing chamber 3, lower the water level of the sample sealing chamber 3 through the drain valve 10 and expose the tip of the sample support 13 to the water surface; Place all the side-sealed concrete test pieces 4 on the top of the test piece support 13 and temporarily avoid contact with water, cover the upper cover of the sample sealing chamber 3 and seal it well; open the valve 16 on the outlet pipe 7, and the water starts to flow from the The constant pressure water supply sealed bottle 1 is replenished into the sample sealed chamber 3, the gas enters the constant pressure water supply sealed bottle 1 through the balance inlet pipe 6 and the water level in the sample sealed chamber 3 gradually rises until the internal water level submerges the test piece 4 When the height is 3mm, the regulating valve 11 is closed, the water level in the sample sealing chamber 3 remains unchanged, and the water level in the L-shaped water level gauge 12 continues to rise to reach a balance state when it is 1mm away from the top, so that the computer starts to collect the constant value according to the time interval set in advance. Quality data for pressurized water units. As the concrete specimen 4 absorbs water, the air pressure in the sample sealing chamber 3 drops slightly, water continues to be replenished from the constant pressure water supply sealing bottle 1 to the sample sealing chamber 3, and the pressure of the gas cavity in the upper part of the constant pressure water supply sealing bottle 1 drops, The external atmosphere is supplemented to the inside of the constant-pressure water supply sealed bottle 1 through the balance air intake pipe 6 and reaches a new equilibrium state. After balancing, the liquid level in the L-shaped water level gauge 12 remains unchanged, and the effective depth corresponding to the bottom surface of the test piece submerged in water is constant. , the decrease in mass of electronic balance 2 collected by computer is equal to the increase in mass of concrete specimen 4, and the surface capillary water absorption of concrete specimen can be calculated through the mass change.

The beneficial effect of this implementation mode:

1. Since the water absorption quality of the concrete specimen is monitored by indirect measurement of the quality change of the constant pressure water supply unit, it can reduce the accidents caused by factors such as manually drying the free water on the bottom surface of the concrete specimen, and the bottom surface of the specimen being separated from free water for a period of time. error;

2. Because the electronic balance is used to measure the quality change of the constant pressure water supply unit to indirectly measure the water absorption quality of the concrete specimen, real-time, continuous, fully automatic and long-term tracking measurement can be achieved, and it can be used to measure and study concrete materials for a long time Mass change of surface water absorption and its surface capillary water absorption. This embodiment can strictly meet the hydraulic boundary condition that the effective depth of the concrete specimen submerged in water is constant to a small value required by the surface capillary water absorption test, and can perform real-time, fully automatic, and long-term continuous testing with high precision. The reproducibility of the results is good, the test operation is convenient, and it can be applied to the experimental research of the pore (crack) structure of concrete materials, surface capillary water absorption and actual engineering durability testing.

Prove beneficial effect of the present invention by following examples:

Embodiment one:

In this embodiment, a concrete surface capillary water absorption automatic testing system is composed of a constant pressure water supply unit, an electronic balance 2 and a test piece water absorption unit. The constant pressure water supply unit and the test piece water absorption unit pass through the outlet pipe 7, the silicone hose 8 and the inlet The water pipe 9 is connected;

The constant pressure water supply unit is composed of a constant pressure water supply sealed bottle 1, a gas communication pipe 5, a balance inlet pipe 6 and a water outlet pipe 7; the electronic balance 2 is arranged at the bottom of the constant pressure water supply sealed bottle 1 and is used to measure the The weight of the pressure water supply unit; wherein, the gas communication pipe 5 and the balance air intake pipe 6 are all arranged on the upper end of the constant pressure water supply sealed bottle 1, and the end of the gas communication pipe 5 inside the constant pressure water supply sealed bottle 1 is arranged near the constant pressure water supply seal On the upper end of the bottle 1, one end of the balanced air intake pipe 6 inside the constant pressure water supply sealed bottle 1 is arranged near the lower end of the constant pressure water supply sealed bottle 1; the upper part of the gas communication pipe 5 is provided with a gas valve 14; the upper part of the balanced air intake pipe 6 is provided with A gas valve 15; a needle tube is arranged at the bottom of the balance inlet pipe 6; one end of the water outlet pipe 7 with the valve 16 communicates with the side end of the bottom of the constant pressure water supply sealed bottle 1, and the other end communicates with the water inlet pipe 9 through the silicone hose 8. The water inlet pipe 9 communicates with the bottom side of the sample sealing chamber 3;

The sample water absorption unit is composed of a sample sealing chamber 3, a water inlet pipe 9, a drain valve 10, a regulating valve 11, an L-shaped water level gauge 12 and a sample support member 13; wherein, the upper part of the sample sealing chamber 3 is provided with a A level 18 is provided with a water inlet pipe 9 at the lower end, an L-shaped water level gauge 12 is arranged at the lower end of the right side of the sealed chamber 3, and the other end of the L-shaped water level gauge 12 is set upward; a regulating valve 11 is arranged at the upper right side of the sample sealed chamber 3 The drain valve 10 is set at the bottom of the sample sealing chamber 3; the inside of the bottom of the sample sealing chamber 3 is provided with three sample supports 13 of equal height.

The common production method of concrete specimen 4 is as follows: dry the concrete specimens cured in the laboratory (cured for a certain age) or the concrete specimens obtained by taking cores on site at a temperature of 60°C to constant weight, and then dry the concrete specimens in the concrete specimens. All sides of the test piece are painted with epoxy resin or paraffin material for waterproof sealing treatment, and finally the dried test piece is placed in a dry environment and cooled to room temperature.

The shape of the concrete specimen 4 can be a cylinder or a prism.

In this implementation example, the electronic balance 2 is used to measure the quality of the constant pressure water supply unit in real time. 50mm cylinder (the height is not limited, but the sample sealing chamber 3 whose height matches the length of the test piece must be used), and the 4 sides are sealed with epoxy resin for waterproof; gas connecting pipe 5, balanced air inlet pipe 6, water outlet pipe 7. Both the water inlet pipe 9 and the L-shaped water level gauge 12 are plexiglass tubes with an outer diameter of 6 mm and a wall thickness of 1 mm; the needle tube connected to the bottom end of the balanced air intake pipe 6 (its inner diameter is 0.5 to 1.5 mm, and the inner diameter of the needle tube can be adjusted to adapt to Measurement of different materials) In this embodiment, it is a needle tube for injection with an inner diameter of 1 mm; the height of the sample support 13 is 10 mm.

The test method of a kind of concrete surface capillary water absorption automatic test system of the present embodiment is as follows:

1. Close the valve 16 on the water outlet pipe 7, fill the constant pressure water supply sealed bottle 1 with water until it does not submerge the lower end of the gas communication pipe 5; open the gas valve 14 on the gas communication pipe 5 and the gas valve on the balance inlet pipe 6 15 and seal the constant pressure water supply sealing bottle 1, then close the gas valve 14 on the upper part of the gas communication pipe 5; open the valve 16 on the water outlet pipe 7, the water inside the constant pressure water supply sealing bottle 1 flows out through the water outlet pipe 7, and the constant pressure water supply The water level in the sealed bottle 1 drops slightly, the air pressure in the inner cavity drops slightly, and the water level in the balanced air intake pipe 6 drops quickly. When the water level drops to the lower end of the balanced air intake pipe 6 and the gas begins to enter the constant pressure water supply through the balanced air intake pipe 6 When the bottle 1 is sealed, the valve 16 on the water outlet pipe 7 is closed, and the liquid in the balanced intake pipe is emptied, and the liquid inside the sealed bottle 1 is in a balanced state for constant pressure water supply;

2. Use a silicone hose 8 to connect the outlet pipe 7 with the water inlet pipe 9, close the drain valve 10, open the regulating valve 11, add water to the sample sealing chamber 3 until the water inlet pipe 9 and the L-shaped water level gauge 12 and the sample are submerged The connecting hole of the sealing chamber 3 requires the water level to submerge the top 3mm of the sample support member 13, cover the top cover of the sample sealing chamber 3 and seal it well; adjust the height adjustment foot 17 to change the height of the test piece sealing bottle 3 to The internal liquid level is 15mm lower than the needle tip level of the balance inlet pipe 6, and the valve 16 on the outlet pipe 7 is opened, and the water in the constant pressure water supply sealing bottle 1 starts to replenish into the sample sealing chamber 3 and empty the silicone hose 8 If the gas that may exist, close the regulating valve 11, the water level in the sample sealing chamber 3 remains unchanged, and the water level in the L-shaped water level gauge 12 continues to rise and overflow may occur; adjust the height regulating foot 17 so that the gas no longer passes through the balance intake pipe 6 Enter the constant pressure water supply seal bottle 1 and the corresponding equilibrium water level in the L-shaped water level gauge 12 is lower than the top 1mm of the L-shaped water level gauge, and at the same time control the level of the water absorption unit of the test piece through the level gauge 18; the height and water level of the water absorption unit of the test piece have been adjusted. The whole system is in a state of water level balance; at this time, if a small amount of water is sucked from the top of the L-shaped water level gauge, the gas will enter the constant pressure water supply seal bottle 1 through the balance inlet pipe 6, and the whole system will be in a balanced state again;

3. Close the valve 16 on the outlet pipe 7, open the regulating valve 11, open the upper cover of the sample sealing chamber 3, lower the water level of the sample sealing chamber 3 through the drain valve 10 and expose the tip of the sample support 13 to the water surface; Place all the side-sealed concrete test pieces 4 on the top of the test piece support 13 and temporarily avoid contact with water, cover the upper cover of the sample sealing chamber 3 and seal it well; open the valve 16 on the outlet pipe 7, and the water starts to flow from the The constant pressure water supply sealed bottle 1 is replenished into the sample sealed chamber 3, the gas enters the constant pressure water supply sealed bottle 1 through the balance inlet pipe 6 and the water level in the sample sealed chamber 3 gradually rises until the internal water level submerges the test piece 4 When the height is 3mm, the regulating valve 11 is closed, the water level in the sample sealing chamber 3 remains unchanged, and the water level in the L-shaped water level gauge 12 continues to rise to reach a balance state when it is 1mm away from the top, so that the computer starts to collect the constant value according to the time interval set in advance. Quality data for pressurized water units. As the concrete specimen 4 absorbs water, the air pressure in the sample sealing chamber 3 drops slightly, water continues to be replenished from the constant pressure water supply sealing bottle 1 to the sample sealing chamber 3, and the pressure of the gas cavity in the upper part of the constant pressure water supply sealing bottle 1 drops, The external atmosphere is supplemented to the inside of the constant-pressure water supply sealed bottle 1 through the balance air intake pipe 6 and reaches a new equilibrium state. After balancing, the liquid level in the L-shaped water level gauge 12 remains unchanged, and the effective depth corresponding to the bottom surface of the test piece submerged in water is constant. , the computer collects the mass decrease of the electronic balance 2 at a time interval of 2 minutes, which is equal to the increase in the mass of the concrete specimen 4, and the surface capillary water absorption of the concrete specimen can be calculated through the mass change.

The electronic balance is connected to the computer through the data line, and the quality data is automatically collected by the computer at a certain time interval, and the quality change of the water supply unit is continuously monitored in real time, that is, the quality change of the water in the constant pressure water supply sealed bottle 1 .

The data collection interval can be shorter in the early stage of the test, and the data collection interval can be set relatively longer after the quality change slows down in the later stage.

To calculate the surface capillary water absorption of the above-mentioned concrete specimens, the steps are as follows:

1. The initial mass test data of electronic balance 2 is M ₀ (kg), and the i-th mass measurement data at time t _i (min) after that is M _i , then the actual water absorption mass of the concrete specimen within t _i time is M ₀ -M _i , at this time, the water absorption volume V _i (m) per unit area within the time t _i can be calculated according to the following formula:

V _i =(M ₀ -M _i )/ρA ①

Among them, A (m ² ) is the area of the bottom surface of the concrete specimen in contact with water, and ρ is the density of water (kg/m ³ );

2. Carry out linear fitting between different time t _i and the corresponding unit area water absorption volume V _i (m) according to the following formula:

$V=S\sqrt{t}+\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000387360050000011.png,HDA0000387360050000012.png"\; state="\{\{state\}\}">b</figure-callout>}$ ②

The obtained slope S (m/min ^0.5 ) is the surface capillary water absorption of the tested piece.

3. When the test of the concrete specimen is completed, close the valve 16 of the water outlet pipe 7, open the regulating valve 11, open the top cover of the sample sealing chamber 3 and take out the specimen (repeat the above steps to continue testing the next concrete specimen) surface capillary water absorption of parts).

Use a cylindrical specimen with a diameter of 100 mm and a height of 50 mm. After sealing the side of the specimen and pre-drying, follow the above steps to collect the mass data of the electronic balance 2 every 2 minutes, and calculate the water absorption mass per unit area according to the formula ① After m _i , linear regression is performed according to formula ②, and the slope obtained after the regression is the capillary water absorption S of the concrete specimen. The test results are shown in Figure 2, where · represents the measured data, and — represents the fitting curve.

The function expression of the fitted curve obtained by the least square method is:

$V=0.039\sqrt{t}-0.101$ ③

The correlation R between the fitting function and the measured data is 0.9948. It can be seen from the above formula ③ that the surface capillary water absorption S of the specimen is 0.039m/min ^0.5 .

In each above-mentioned embodiment example, the structure of each component, setting position and connection thereof all can be changed to some extent, on the basis of the technical solution of the present invention, the improvement and equivalent replacement of individual components should not be excluded from the scope of the present invention. outside the scope of protection.

Claims (7)

1. A concrete surface capillary water absorption automatic test system is characterized in that the concrete surface capillary water absorption test system is made of constant pressure water supply unit, electronic balance (2) and specimen water absorption unit, constant pressure water supply unit and test piece The suction unit of the piece is connected through the outlet pipe (7), the silicone hose (8) and the water inlet pipe (9); The constant pressure water supply unit is composed of a constant pressure water supply sealed bottle (1), a gas connecting pipe (5), a balance inlet pipe (6) and a water outlet pipe (7); the electronic balance (2) is set at a constant pressure The bottom of the sealed water supply bottle (1) is used to measure the weight of the constant pressure water supply unit; among them, the gas connecting pipe (5) and the balance inlet pipe (6) are both arranged on the upper end of the constant pressure water supply sealing bottle (1), and the gas connecting pipe (5) One end inside the constant pressure water supply bottle (1) is set close to the upper end of the constant pressure water supply bottle (1), and the end of the balance air intake pipe (6) inside the constant pressure water supply bottle (1) is set close to The lower end of the constant pressure water supply seal bottle (1); a gas valve (14) is arranged on the upper part of the gas connecting pipe (5); a gas valve (15) is arranged on the upper part of the balanced air inlet pipe (6); the bottom of the balanced air inlet pipe (6) A needle tube is provided; one end of the water outlet pipe (7) with a valve (16) communicates with the bottom side end of the constant pressure water supply seal bottle (1), and the other end communicates with the water inlet pipe (9) through a silicone hose (8). The water inlet pipe (9) communicates with the bottom side of the sample sealing chamber (3); The sample water absorption unit is composed of sample sealing chamber (3), water inlet pipe (9), drain valve (10), regulating valve (11), L-shaped water level gauge (12) and sample support (13) ; Wherein, a level gauge (18) is arranged on the upper part of the sample sealed chamber (3), a water inlet pipe (9) is arranged at the lower end, and an L-shaped water level gauge (12) is arranged at the lower end of the right side of the sealed chamber (3). The other end of the water level gauge (12) is set upward; the upper end of the right side of the sample sealing chamber (3) is provided with a regulating valve (11); the drain valve (10) is set at the bottom of the sample sealing chamber (3); the sample sealing chamber (3) Three sample supports (13) of equal height are provided on the inner side of the bottom. 2. An automatic testing system for capillary water absorption of concrete surface according to claim 1, characterized in that the water absorption unit of the specimen further includes a height adjustment foot (17) and a level (18). 3. An automatic testing system for capillary water absorption of concrete surface according to claim 1, characterized in that three equal-height height adjustment feet (17) are arranged on the outside of the sample sealing chamber (3), and are located on the On the horizontal operating platform (19). 4. An automatic testing system for concrete surface capillary water absorption according to claim 1, characterized in that the electronic balance (2) has a measuring range of 1000g and an accuracy of 0.001g. 5. A concrete surface capillary water absorption automatic test system according to claim 1, characterized in that said gas communication pipe (5), balanced air inlet pipe (6), water outlet pipe (7), water inlet pipe (9) ) and the L-shaped water level gauge (12) are made of plexiglass. 6. A concrete surface capillary water absorption automatic testing system according to claim 1, characterized in that the top of the L-shaped water level gauge (12) is higher than the vertical direction of the top of the sample support (13) The distance is 5mm. 7. use the test method of a kind of concrete surface capillary water absorption automatic test system according to claim 1, it is characterized in that described test method comprises the steps: 1. Close the valve (16) on the outlet pipe (7), fill the constant pressure water supply bottle (1) with water until it does not submerge the lower end of the gas connecting pipe (5); open the gas valve on the gas connecting pipe (5) (14) and balance the gas valve (15) on the inlet pipe (6) and seal the constant pressure water supply bottle (1), then close the gas valve (14) on the upper part of the gas communication pipe (5); open the water outlet pipe (7 ), the water inside the constant pressure water supply sealing bottle (1) flows out through the outlet pipe (7), the water level in the constant pressure water supply sealing bottle (1) drops slightly, the air pressure in the internal cavity drops slightly and the balance enters The water level in the trachea (6) drops rapidly, and when the water level drops to the lower end of the balanced air intake pipe (6) and the gas begins to enter the constant pressure water supply seal bottle (1) through the balanced air intake pipe (6), close the water outlet pipe (7 ) on the valve (16) to complete the emptying of the liquid in the balanced intake pipe, and the liquid inside the constant pressure water supply sealed bottle (1) is in a balanced state; 2. Use a silicone hose (8) to connect the outlet pipe (7) with the water inlet pipe (9), close the drain valve (10), open the regulating valve (11), and add water to the sample sealing chamber (3) until it is submerged The water inlet pipe (9) and the L-shaped water level gauge (12) communicate with the sample sealing chamber (3). At the same time, the water level is required to submerge the top of the sample support (13) by 3 mm, and the sample sealing chamber (3) is covered. The top cover is sealed well; adjust the height adjustment foot (17) to change the height of the test piece sealed bottle (3) until the internal liquid level is 10-15mm lower than the needle tip level of the balance inlet pipe (6), open the water outlet pipe (7 ), the water in the constant pressure water supply sealing bottle (1) starts to replenish and empty the gas that may exist in the silicone hose (8), and close the regulating valve (11 ), the water level in the sample sealing chamber (3) remains unchanged, and the water level in the L-shaped water level gauge (12) continues to rise and may overflow; adjust the height adjustment foot (17) so that the gas no longer passes through the balance inlet pipe (6) Enter the constant pressure water supply sealed bottle (1) and the corresponding equilibrium water level in the L-shaped water level gauge (12) is 1mm lower than the top of the L-shaped water level gauge, and at the same time control the level of the water absorption unit of the test piece through the level meter (18); the water absorption unit of the test piece After the height and water level are adjusted, the whole system is in a state of water level balance; at this time, if a small amount of water is sucked from the top of the L-shaped water level gauge, the gas will enter the constant pressure water supply seal bottle (1) through the balance inlet pipe (6), and make the whole system to regain balance; 3. Close the valve (16) on the outlet pipe (7), open the regulating valve (11), open the upper cover of the sample sealing chamber (3), and lower the water level of the sample sealing chamber (3) through the drain valve (10) And make the tip of the sample support (13) exposed to the water surface; place all the side-sealed concrete specimens (4) on the upper part of the specimen support (13) and temporarily avoid contact with water, and cover the sample sealing chamber (3 ) and seal it well; open the valve (16) on the water outlet pipe (7), water starts to replenish from the constant pressure water supply sealed bottle (1) to the sample sealed chamber (3), and the gas passes through the balance inlet pipe (6 ) into the constant pressure water supply sealed bottle (1) and the water level in the sample sealed chamber (3) gradually rises, and when the internal water level submerges the test piece (4) to a height of 3 mm, close the regulating valve (11), and the sample The water level in the sealed chamber (3) remains unchanged and the water level in the L-shaped water level gauge (12) continues to rise to 1mm from the top when it reaches a balanced state, allowing the computer to start collecting quality data of the constant pressure water supply unit at a preset time interval. As the concrete specimen (4) absorbs water, the air pressure in the sample sealing chamber (3) drops slightly, and water continues to be replenished from the constant pressure water supply sealing bottle (1) to the sample sealing chamber (3), and the constant pressure water supply sealing bottle (1) The pressure of the upper gas cavity drops, and the external atmosphere replenishes to the inside of the constant-pressure water supply sealed bottle (1) through the balance inlet pipe (6) and reaches a new equilibrium state. After balancing, the liquid level in the L-shaped water level gauge (12) remains unchanged, and the effective depth corresponding to the bottom surface of the test piece submerged in water is constant. 2) It is measured that the mass decrease of the computer-collected electronic balance (2) is equal to the mass increase of the concrete specimen (4), and the surface capillary water absorption of the concrete specimen can be calculated through the mass change.

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