CN108225472A - A kind of method and system for measuring cement base test specimen cracking degree - Google Patents

Abstract

The invention discloses a method and system for measuring the cracking degree of a cement-based test piece, wherein the method includes the following steps: placing the cement-based test piece with several crack regions in a liquid filler, making the liquid filling Fill the interior of several crack areas of the cement-based test piece; cool the liquid filling and make it solidify, take out the cement-based test piece, and heat the cement-based test piece so that the filling inside several crack areas melts and flows out; collect The mass of the outflowing filler is weighed, and the volume of the outflowing filler is calculated through a predetermined mass-density relationship, thereby obtaining the total volume of all cracked regions of the cement-based specimen. The method and system for measuring the cracking degree of cement-based specimens in the present invention can be widely used in the measurement of crack volumes of concrete specimens of various shapes, and conveniently provide an experimental basis for concrete self-repair performance evaluation and other durability test research.

Description

Method and system for measuring cracking degree of cement-based test piece

technical field

The invention relates to the technical field of self-repairing of cement-based materials, in particular to a method and system for measuring the cracking degree of cement-based test pieces.

Background technique

Cement-based materials are one of the most widely used materials in the research of modern building materials, especially concrete materials. At present, the research on the self-healing performance of cement-based materials is a hotspot in the research of civil engineering materials, and the degree of crack repair is one of the indicators to evaluate the self-healing efficiency. In order to evaluate the degree of repair of the fracture, the volume of the fracture needs to be measured. The traditional crack volume measurement is mainly through the reconstruction and analysis of the three-dimensional contour of the concrete crack surface. If such methods are used directly, it is necessary to introduce specific equipment and computer program programming, and the data processing process is complicated. Moreover, because it is only the measurement of the crack surface, it can only measure the surface profile of the crack surface of the concrete sample, and roughly calculate the total volume of the crack, but cannot accurately measure the volume of each crack of the concrete sample.

At the same time, the existing measurement methods mainly include the method of measuring cracks with an electrical microscope, but it can only roughly measure the average width of cracks on the concrete surface or the total area of cracks. Therefore, the existing two methods are difficult to achieve accurate measurement of the crack volume of concrete samples.

In addition, when testing spherical concrete samples, since the bearing plate is a smooth plane, there is a possibility of sample deviation, which will also affect the stability of the test experiment.

Thereby prior art still needs to improve and improve.

Contents of the invention

In view of the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a method and system for measuring the cracking degree of cement-based specimens, which can be conveniently and simply widely used in the measurement of crack volumes in concrete specimens of various shapes. Self-healing performance evaluation and other durability test research provide the experimental basis.

In order to achieve the above object, the present invention has taken the following technical solutions:

A method for measuring the degree of cracking of a cement-based test piece, comprising the steps of:

Filling the cement-based test piece: place the cement-based test piece with several cracked areas in the liquid filling, so that the liquid filling fills the interior of the several cracked areas of the cement-based test piece;

Obtain the filler to be tested: cool the liquid filler and allow it to solidify, take out the cement-based test piece, and heat the cement-based test piece to melt the inner filler in several crack areas;

Obtain the volume of the crack area: collect the outflowing filler and weigh its mass, calculate the volume of the outflowing filler through the predetermined mass-density relationship, so as to obtain the total volume of all crack areas of the cement-based specimen.

In the method for measuring the cracking degree of the cement-based test piece, the cement-based test piece with several crack regions is placed in the liquid filling, so that the liquid filling fills the several cracks of the cement-based test piece Before the steps inside the region, also include the steps:

Use sealers to wrap and seal the parts of the cement-based specimens other than several crack areas.

In the method for measuring the degree of cracking of the cement-based test piece, before the step of using the sealant to wrap and seal the parts other than the several crack areas on the cement-based test piece, the steps include:

Mark the location of all cracked areas of the cement-based specimen.

In the method for measuring the cracking degree of the cement-based test piece, the cement-based test piece with several crack areas is placed in the liquid filler, so that the liquid fill fills the several crack areas of the cement-based test piece The internal steps specifically include:

Put the solid filling in the vacuum dish, heat the vacuum dish to melt the filling into a liquid state, and then place the cement-based specimen with several cracked areas in the liquid filling;

Seal the vacuum vessel, use a vacuum pump to extract air from the vacuum vessel, so that the liquid filler completely fills the interior of several cracks in the cement-based specimen;

Stop the vacuum pump.

In the method for measuring the cracking degree of the cement-based test piece, the liquid filler is cooled and allowed to solidify, the cement-based test piece is taken out, and the cement-based test piece is heated so that the fillers in several crack areas melt and flow out The steps specifically include:

Cool the liquid filler and allow it to solidify, remove the filled cement-based test piece and remove the filler from the surface of the seal and crack area;

The cement-based test piece is placed in water and heated to melt and flow out the fillers in several crack areas on the cement-based test piece.

In the method for measuring the cracking degree of a cement-based test piece, the filler is a waxy filler or a lipid filler.

A system for measuring the extent of cracking in cementitious test pieces comprising:

Cementitious specimens with several cracked regions;

A filling device used to fill the interior of several crack areas of the cement-based test piece with liquid filling;

A heating device for heating the cement-based test piece so that the filling inside several crack areas melts and flows out;

Weighing device for measuring the mass of the discharged filling.

In the system for measuring the cracking degree of a cement-based test piece, seals are pasted on parts of the cement-based test piece other than several crack areas.

In the system for measuring the degree of cracking of cement-based specimens, the filling device includes a water bath, a vacuum dish, a vacuum pump, a trachea and fillers, the vacuum dish is arranged inside the water bath, and the filler is arranged in a vacuum The inside of the dish, and the vacuum pump communicates with the inside of the vacuum dish through a gas pipe.

The system for measuring the cracking degree of the cement-based test piece further includes a drying device for drying the filler.

Compared with the prior art, the present invention provides a method and system for measuring the cracking degree of a cement-based test piece, wherein the method includes the following steps: filling the cement-based test piece: filling the cement-based test piece with several crack regions Place the piece in the liquid filling, so that the liquid filling fills the interior of several cracks of the cement-based test piece; obtain the filling to be tested: cool the liquid filling and make it solidify, take out the cement-based test piece, The cement-based test piece is heated to melt and flow out the fillers in several crack regions; to obtain the volume of the crack region: collect the fillers that flow out and weigh their mass, and calculate the volume of the fillers that flow out through the predetermined mass-density relationship, so that Find the total volume of all cracked areas of the cement-based specimen. The method and system for measuring the cracking degree of cement-based specimens in the present invention not only have simple operation, high repeatability, no need to introduce specific equipment, and low cost, it is convenient to be widely used in the measurement of crack volume of concrete specimens of various shapes Therefore, it can conveniently provide an experimental basis for the evaluation of concrete self-repair performance and other durability test research.

Description of drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of a cement-based test piece in a system for measuring the cracking degree of a cement-based test piece provided by the present invention.

Fig. 2 is a schematic structural view of a preferred embodiment of the filling device in the system for measuring the cracking degree of cement-based specimens provided by the present invention.

Fig. 3 is a flowchart of a method for measuring the cracking degree of a cement-based test piece provided by the present invention.

Fig. 4 is a flowchart of step S100 in the method for measuring the cracking degree of a cement-based test piece provided by the present invention.

Fig. 5 is a flowchart of step S200 in the method for measuring the cracking degree of a cement-based test piece provided by the present invention.

In the figure, 10, cement-based test piece; 11, crack area; 12, seal; 20, water bath; 30, vacuum dish; 40, vacuum pump; 50, trachea; 60, filler.

Detailed ways

The present invention provides a method and system for measuring the cracking degree of cement-based test pieces. In order to make the purpose, technical solution and effect of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The system for measuring the degree of cracking of cement-based specimens in the present invention includes cement-based specimens to be measured, please refer to Fig. The shape of the test piece 10 is generally cylindrical, and it has several crack areas 11 (only one of them is shown in the figure), and a sealing member 12 is pasted on the part of the cement-based test piece other than the several crack areas, So that only the crack area 11 on the cement-based test piece 10 is exposed to the air. At this time, the present invention can obtain the total volume of several crack regions by filling the part of the crack region exposed to the air, and then calculating the volume of the filled part.

In the system for measuring the cracking degree of the cement-based test piece provided by the present invention, it also includes a filling device for filling the interior of several crack regions of the cement-based test piece with the liquid filler. Please continue to refer to Fig. 2, which is a schematic structural view of a preferred embodiment of the filling device provided by the present invention, the filling device (not labeled among the figures) includes a water bath 20, a vacuum vessel 30, a vacuum pump 40, an air pipe 50 and a filler 60 , the vacuum vessel 30 is arranged inside the water bath 20 , the filler 60 is arranged inside the vacuum vessel 30 , and the vacuum pump 40 communicates with the inside of the vacuum vessel 30 through the gas pipe 50 . Firstly, the filler in the vacuum dish is solid at room temperature. When the water bath continues to heat the vacuum dish so that the filling in the vacuum dish is completely melted into a liquid state, the cement-based specimen can be placed in the vacuum dish for filling. And by using a vacuum pump to evacuate the vacuum vessel, the liquid filler can be accelerated to completely enter the crack area of the sample.

It is worth noting that the filler in the present invention is solid at normal temperature and can be melted into liquid after heating. Substances of water, such as wax, fat, etc., the present embodiment adopts granular wax with a melting point of about 58°C. Moreover, when substances such as wax and fat are used as waxy fillers or lipid fillers, they have better fluidity after melting, and are neither soluble in water nor react with concrete samples, thereby avoiding measurement errors.

The sealing member in the present invention can be the sealing tape with good wrapping properties, by using the sealing tape with good wrapping properties to seal and wrap the parts other than several crack areas on the cement-based test piece, after the cement-based test piece is filled, tear off The tape easily removes the excess filler, which avoids the tedious work of scraping off the solidified wax on the remaining surface of the cement-based sample in the later stage, and the influence of removing the defects of the sample.

In the system for measuring the cracking degree of the cement-based test piece provided by the present invention, it also includes a heating device for heating the cement-based test piece so that the fillers in several crack regions melt and flow out. The heating device can specifically be the same water bath as in the filling device, and the filling is heated by the water bath to make the filling flow out and float on the water surface, and then salvage and collect.

In addition, the system for measuring the cracking degree of the cement-based test piece provided by the present invention also includes a drying device for drying the filling and a weighing device for measuring the quality of the flowing out filling. The drying device can specifically be a water-absorbing rag or a fan. For example, after the filling flows out and is collected, a fan can be used to generate air flow to take away the water vapor on the surface of the filling and accelerate the evaporation of residual moisture in the filling. Afterwards, measure the mass of the dried filling with a weighing device, such as a balance, an electronic scale, etc., and calculate the volume of the collected filling according to the mass-density relationship of the filling, so as to obtain the total volume of the crack area. volume.

Based on the above-mentioned system for measuring the degree of cracking of the cement-based test piece, please refer to Fig. 3, the present invention also provides a method for measuring the degree of cracking of the cement-based test piece, which includes the following steps:

S100. Filling the cement-based test piece: placing the cement-based test piece with several cracked regions in the liquid filler, so that the liquid filler fills the interior of the several cracked regions of the cement-based test piece;

S200. Obtaining the filler to be tested: cooling the liquid filler and allowing it to solidify, taking out the cement-based test piece, heating the cement-based test piece so that the inner filler in several crack regions melts and flows out;

S300. Obtaining the volume of the cracked area: collecting the outflowing filler and weighing its mass, and calculating the volume of the outflowing filler according to a predetermined mass-density relationship, so as to obtain the total volume of all cracked areas of the cement-based test piece.

Further, before the step S100, it also includes the steps of:

S101. Use a sealing member to wrap and seal the parts of the cement-based test piece other than several crack areas.

Furthermore, before step S1001, the steps include:

S102. Mark the positions of all crack regions of the cement-based test piece. Specifically, the concrete sample that has been produced and has several crack areas can be placed under an instrument that can observe tiny cracks, such as observing the positions of all surface crack areas under an optical microscope, and marking the crack positions. This facilitates the subsequent step of sealing the surface of the non-crack area with a sealing tape, and improves the accuracy of sealing.

Specifically, please refer to FIG. 4, the step S100 specifically includes:

S110, placing the solid filling in a vacuum dish, heating the vacuum dish to melt the filling into a liquid state, and then placing the cement-based test piece with several crack regions in the liquid filling;

S120, sealing the vacuum dish, using a vacuum pump to extract air from the vacuum dish, so that the liquid filler completely fills the interior of several crack regions of the cement-based test piece;

S130, stop the vacuum pump from working.

More specifically, please refer to FIG. 5, the step S200 specifically includes:

S210, cooling the liquid filler and allowing it to solidify, taking out the filled cement-based test piece and removing the filler on the surface of the sealing member and the crack area;

S220, heating the cement-based test piece in water, so that the fillers inside the several crack regions on the cement-based test piece are melted and flowed out.

In order to understand the present invention better, below in conjunction with Fig. 1～Fig. 5, the method for measuring the degree of cracking of the cement-based specimen provided by the present invention is described in detail:

Sealing and wrapping the cracked test piece: take a concrete sample with a size of φ100mm×50mm, place the sample on a pressure testing machine and load it to make cracks. Place the cracked sample under an optical microscope to observe the crack position, mark it and wrap the adjacent surface of the crack with sealing tape.

Liquid wax immerses into cracks: In this embodiment, granular wax with a melting point of about 58°C is used. The granular wax was placed in a vacuum dish and placed in a water bath, heated to 70° C. to completely melt the solid granular wax. At this point, place the sample wrapped in the previous step in a vacuum dish and completely soak it in liquid wax. Use a vacuum pump to evacuate for about 30 minutes to accelerate the entry of liquid wax into the cracks of the sample.

Clean the wax on the surface of the sample: After the above steps are completed, gradually lower the temperature of the water bath. When the liquid wax is completely solidified, take out the sample, and use a knife to scrape off the excess wax covering the adhesive tape and the cracks for reuse. And the adhesive tape was torn off to obtain a concrete sample with only cracks filled with wax.

Take out the wax in the crack of the sample: Soak the sample finally obtained in the 3rd step in hot water at a temperature of about 70°C for about 30 minutes, until the wax is completely melted and flows out from the crack. At this time, the hot water is lowered to normal temperature, the wax solidifies and floats on the water surface, and the wax is removed with a dense sieve. After the wax surface is dry, the wax is placed on a balance to weigh the mass, and the collected wax is calculated according to the mass-density relationship of the wax. The volume of the wax obtained, and finally the total volume of the crack is obtained.

This embodiment avoids the introduction of specific equipment, the measurement steps are simple, and the economical performance is good. Granular wax is used as the measurement medium which does not react with the concrete sample and can be used repeatedly. The measured total crack volume is more accurate.

In summary, the method and system for measuring the degree of cracking of a cement-based test piece provided by the present invention, wherein the method includes the following steps: filling the cement-based test piece: placing the cement-based test piece with several crack regions in In the liquid filling, make the liquid filling fill the interior of several cracks of the cement-based test piece; obtain the filling to be tested: cool the liquid filling and make it solidify, take out the cement-based test piece, and test the cement-based test piece. The heating of the parts makes the fillers in several crack areas melt and flow out; obtain the volume of the crack area: collect the outflowing fillers and weigh their mass, and calculate the volume of the outflowing fillers through the predetermined mass-density relationship, so as to obtain the cement The total volume of all fractured regions of the base specimen. The method and system for measuring the cracking degree of cement-based specimens in the present invention not only have simple operation, high repeatability, no need to introduce specific equipment, and low cost, it is convenient to be widely used in the measurement of crack volume of concrete specimens of various shapes Therefore, it can conveniently provide an experimental basis for the evaluation of concrete self-repair performance and other durability test research.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. a method for measuring the degree of cracking of cement-based test piece, is characterized in that, comprises the steps: Filling the cement-based test piece: place the cement-based test piece with several cracked areas in the liquid filling, so that the liquid filling fills the interior of the several cracked areas of the cement-based test piece; Obtain the filler to be tested: cool the liquid filler and allow it to solidify, take out the cement-based test piece, and heat the cement-based test piece to melt the inner filler in several crack areas; Obtain the volume of the crack area: collect the outflowing filler and weigh its mass, calculate the volume of the outflowing filler through the predetermined mass-density relationship, so as to obtain the total volume of all crack areas of the cement-based specimen. 2. the method for measuring the degree of cracking of a cement-based test piece according to claim 2, is characterized in that, in the described cement-based test piece with several crack regions placed in a liquid filler, the liquid filler Before the step of filling the interior of several cracked regions of the cement-based specimen, further include the steps of: Use sealers to wrap and seal the parts of the cement-based specimens other than several crack areas. 3. the method for measuring the degree of cracking of cement-based test piece according to claim 3, is characterized in that, before the step of using sealant to wrap and seal the parts other than several crack areas on the cement-based test piece, also include step: Mark the location of all cracked areas of the cement-based specimen. 4. the method for measuring the degree of cracking of cement-based test piece according to claim 3, is characterized in that, the described cement-based test piece with several crack regions is placed in the filling of liquid state, makes the filling of liquid state be full of The internal steps of several crack regions of the cement-based specimen specifically include: Put the solid filling in the vacuum dish, heat the vacuum dish to melt the filling into a liquid state, and then place the cement-based specimen with several cracked areas in the liquid filling; Seal the vacuum vessel, use a vacuum pump to extract air from the vacuum vessel, so that the liquid filler completely fills the interior of several cracks in the cement-based specimen; Stop the vacuum pump. 5. the method for measuring the degree of cracking of a cement-based test piece according to claim 4, is characterized in that, the filler of the cooling liquid is solidified, the cement-based test piece is taken out, and the cement-based test piece is heated so that several The steps of melting and flowing out of the filler inside the crack area specifically include: Cool the liquid filler and allow it to solidify, remove the filled cement-based test piece and remove the filler from the surface of the seal and crack area; The cement-based test piece is placed in water and heated to melt and flow out the fillers in several crack areas on the cement-based test piece. 6. The method for measuring the degree of cracking of a cement-based test piece according to claim 1, wherein the filler is a waxy filler or a lipid filler. 7. A system for measuring the degree of cracking of a cement-based test piece, characterized in that it comprises: Cementitious specimens with several cracked regions; A filling device used to fill the interior of several crack areas of the cement-based test piece with liquid filling; A heating device for heating the cement-based test piece so that the filling inside several crack areas melts and flows out; Weighing device for measuring the mass of the discharged filling. 8. The system for measuring the cracking degree of a cement-based test piece according to claim 1, characterized in that seals are pasted on parts of the cement-based test piece other than several crack areas. 9. The system for measuring the degree of cracking of a cement-based test piece according to claim 1, wherein the filling device comprises a water bath, a vacuum dish, a vacuum pump, a trachea and fillers, and the vacuum dish is arranged at the bottom of the water bath. Inside, the filler is arranged inside the vacuum vessel, and the vacuum pump communicates with the inside of the vacuum vessel through an air pipe. 10. The system for measuring the cracking degree of a cement-based test piece according to claim 1, further comprising a drying device for drying the filler.