CN202230007U - Cement-based material porosity distribution testing device based on industrial X-ray tomography - Google Patents

Abstract

A testing device for porosity distribution of cement-based materials based on industrial X-ray tomography, comprising: a plastic hose, a plastic test tube with epoxy resin fixed at the bottom, and a vacuum suction device; Two rubber stoppers and the third rubber stopper; the first opening rubber stopper is provided on the test tube hole of the plastic test tube; A vacuum gauge is connected to the conical flask, a vacuum pump is connected to the conical flask through a first vacuum tube, a second vacuum tube is also connected to the conical flask and one end of the conical flask is connected to the second vacuum tube, and the other end of the second vacuum tube is connected to There is a fourth opening rubber plug; the third rubber plug on the plastic hose is connected to the fourth opening rubber plug, the second rubber plug forms a negative pressure connection with the first opening rubber plug when the vacuum pump is working, and the second The rubber plug is separated from the first hole rubber plug when the vacuum pump stops working.

Description

Measuring device for porosity distribution of cement-based materials based on industrial X-ray tomography

technical field

The utility model relates to a testing device for porosity distribution of cement-based materials based on industrial X-ray tomography, in particular to a testing device for three-dimensional porosity distribution of test blocks of concrete, mortar and other cement-based materials. the

Background technique

The porosity of cement-based materials is an important technical parameter that determines the mechanical properties, transmission properties and durability of the material. How to accurately characterize the porosity of cement-based materials has attracted extensive attention of researchers. Porosity testing methods are divided into two categories: quantitative statistical methods and microscopic observation methods. Quantitative statistical methods include mercury injection method, gas adsorption method, boiling water absorption method, heat preservation oil absorption method, etc. These methods can only give the statistical average value of the internal porosity of a certain sample, but cannot obtain the distribution of porosity with space. Microscopic observation methods such as metallographic microscope, electron microscope, and industrial X-ray tomography can visually see where the pores are, and can also approximate the porosity in a certain range based on stereology and statistics, but it is difficult to give The specific distribution of porosity with space. In addition, metallographic microscopes and electron microscopes can only see a section, and the porosity data deduced from a section section is different from the actual three-dimensional porosity data; various X-ray tomography is limited by the spatial resolution of observation, often Only relatively large pores can be observed and characterized, ignoring the gel pores and small capillary pores that account for a large proportion in cement-based materials. Therefore, how to accurately give the three-dimensional porosity distribution inside the cement-based material is a realistic technical problem. the

The utility model calculates the three-dimensional porosity distribution by using the X-ray attenuation difference between a dry cement-based sample and an in-situ saturated cement-based sample. Different from low-resolution medical X-ray tomography, high-resolution industrial X-ray tomography uses the rotation of the sample for tomography, so how to ensure that the sample remains in place during the two scans and the drying and saturation process is a technical problem . The utility model solves the technical problem by connecting the sample part and the vacuum part with a negative pressure and a hose, and provides a method for testing the three-dimensional porosity distribution of cement-based materials by using industrial X-ray tomography. the

Utility model content

The utility model provides a cement-based material porosity distribution testing device based on industrial X-ray tomography, which can keep the X-ray tomography conditions unchanged in the testing process and can realize in-situ. the

A cement-based material porosity distribution testing device based on industrial X-ray tomography, comprising: a plastic hose, a plastic test tube with epoxy resin fixed at the bottom, and a vacuum suction device;

The two ends of the plastic hose are respectively connected with a second rubber plug and a third rubber plug;

A first perforated rubber stopper is provided on the test tube hole of the plastic test tube;

Described vacuum suction device comprises Erlenmeyer flask, is provided with rubber stopper on the bottleneck of Erlenmeyer flask, is connected with vacuum gauge on Erlenmeyer flask, is connected with vacuum pump through first vacuum tube on Erlenmeyer flask simultaneously, and Also be connected with the second vacuum tube on the flask and conical flask is connected with one end of the second vacuum tube, the other end of the second vacuum tube is connected with the fourth opening rubber stopper;

The third rubber plug on the plastic hose is connected to the fourth opening rubber plug, and the second rubber plug forms a negative pressure connection with the first opening rubber plug when the vacuum pump is working. When the vacuum pump stops working, it is separated from the first rubber plug with holes. the

Beneficial effects: the utility model cuts off the vibration effect of the vacuum pump by introducing a conical flask and a plastic hose between the sample and its container, the vacuum pump and the vacuum tube, and adopts a soft connection. The utility model connects the sample container with the vacuum suction system during the vacuum saturation process, and disconnects the connection during the tomography process. The specific operation is as follows: when connecting, put the second rubber stopper at the opening of the first rubber stopper and close Form a loose connection, start the vacuum pump, form a negative pressure in the plastic test tube, and connect the second rubber stopper and the first rubber stopper to the opening of the first rubber stopper by the negative pressure, and stop when the sample is fully saturated. Vacuum pump, after the vacuum returns to the standard atmospheric pressure, the second rubber plug and the first rubber plug are restored to a loose connection, the second rubber plug is removed from the first rubber plug, and a negative pressure is used between the two rubber plugs. The method of pressure connection solves the artificial disturbance. The above scheme is adopted to solve the problem of in-situ testing of two tomographic scans on a rotating industrial X-ray tomography platform, and provides a method for testing the three-dimensional porosity distribution of cement-based materials by using industrial X-ray tomography. Three-dimensional porosity distributions were obtained by in situ testing of industrial tomography grayscale calculations of dry and saturated samples. The utility model achieves the in-situ saturation process by means of vacuuming, thereby reducing the occupied time of the equipment. The utility model can be used for measuring the porosity distribution of various cement-based materials such as various concretes and mortars, solves the problem of difficulty in measuring the porosity distribution of cement-based materials, and has a spatial resolution much higher than that of medical X-ray tomography. the

Description of drawings

Fig. 1 is the structural representation of the utility model. the

Fig. 2 is a flow chart of a method for testing porosity distribution of cement-based materials based on industrial X-ray tomography. the

Detailed ways

Example 1

A cement-based material porosity distribution testing device based on industrial X-ray tomography, comprising: a plastic hose 5, a plastic test tube 4 with epoxy resin fixed at the bottom and a vacuum suction device,

The two ends of the plastic hose 5 are respectively connected with a second rubber plug 7 and a third rubber plug 8,

The first perforated rubber stopper 6 is provided on the test tube hole of the plastic test tube 4,

Described vacuum suction device comprises Erlenmeyer flask 12, is provided with rubber stopper 11 on the bottleneck of Erlenmeyer flask 12, is connected with vacuum gauge 14 on Erlenmeyer flask 12, passes first vacuum tube on Erlenmeyer flask 12 simultaneously 13 is connected with vacuum pump 15, is also connected with second vacuum tube 10 on conical flask 12 and conical flask 12 is connected with one end of second vacuum tube 10, is connected with the 4th opening rubber stopper 9 at the other end of second vacuum tube 10,

The third rubber plug 8 on the plastic hose 5 is connected to the fourth opening rubber plug 9, and the second rubber plug 7 forms a negative pressure connection with the first opening rubber plug 6 when the vacuum pump 15 is working. , the second rubber plug 7 is separated from the first perforated rubber plug 6 when the vacuum pump 15 stops working. the

Example 2:

Step 1: Select samples. In order to verify the reliability of this method, a certain degree of dissolution of calcium-dissolved cement paste samples is selected, so as to ensure that there is a porosity gradient inside the samples. the

Step 2: Vacuum dry the sample to be tested in a vacuum oven for 48 hours and weigh it to a constant weight to ensure that the sample reaches a completely anhydrous state;

Step 3: Take a plastic test tube 4, inject epoxy resin liquid and curing agent into its bottom, after it is cured, use 502 glue to fix the completely dried cement-based material 2 on the cured resin 1, the plastic test tube uses the first Open-hole rubber plug 6 is sealed; fix the plastic test tube 4 on the rotary sample stage of industrial X-ray tomography and perform the first X-ray tomography to obtain the tomographic grayscale data of the completely dry sample. Step 4: Take a rubber The Erlenmeyer flask 12 with stopper 11 sealing is connected with vacuum gauge 14 on the Erlenmeyer flask 12 of sealing, and the vacuum pump 15 is connected with the first vacuum tube 13 on the Erlenmeyer flask 12 of sealing simultaneously, and also on the Erlenmeyer flask 12 of sealing Connect the second vacuum tube 10 and the sealed conical flask 12 is connected with one end of the second vacuum tube 10, and the other end of the second vacuum tube 10 is connected with a fourth opening rubber stopper 9; Connect the two ends of the second rubber stopper 7 and the third rubber stopper 8 respectively, and connect the third rubber stopper 8 to the fourth opening rubber stopper 9; pour 5 into the plastic test tube 4 from the opening of the first rubber stopper 6 % potassium iodide solution 3 and make it exceed more than 5 mm of the cement-based material sample; the second rubber stopper 7 is placed on the opening of the first rubber stopper 6 and forms a loose connection, and the vacuum pump 15 is started to form a negative pressure in the plastic test tube 4 , and the second rubber stopper 7 and the first rubber stopper 6 are sealed and connected to the opening of the first rubber stopper 6 by negative pressure; when the vacuum degree reaches 750 mm Hg negative pressure and is maintained for more than two hours, the sample reaches full saturation , then stop the vacuum pump 15, wait for the vacuum to return to the standard atmospheric pressure, restore the loose connection between the second rubber plug 7 and the first rubber plug 6, and take off the second rubber plug 7 from the first rubber plug 6; keep Under the same test conditions as the first tomography, the second X-ray tomography is performed in situ to obtain the tomographic grayscale data of the fully saturated sample;

Step 5: Use the following formula to calculate the grayscale data of each voxel to obtain the three-dimensional porosity distribution image in the sample:

$\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; satu</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; dry</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; the\; water</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; the\; air</span>}}}$

x, y, z are spatial coordinate positions;

p(x, y, z) is the porosity at x, y, z;

G _satu (x, y, z) is the gray value of the saturated water sample x, y, z;

G _dry (x, y, z) is the gray value of the dry sample x, y, and z;

G _water is the gray value of water or aqueous solution;

G _air is the gray value of air.

The gray values of the aqueous solution and air required in the formula can be obtained from the gray data of industrial X-ray tomography three-dimensional reconstruction, as long as the gray values of the areas completely filled with potassium iodide solution and completely filled with air are selected respectively. the

In order to simplify the data, this embodiment only takes a two-dimensional section in the three-dimensional tomographic image for calculation, and the calculation result is shown in the grayscale image in Figure 3: different grayscales in the figure represent different porosities, the whitest The porosity is 100%, and the blackest porosity is 0. It can be seen from the figure that the porosity in the middle of the sample is the lowest, and the porosity increases toward the two sides, which corresponds to the undissolved part in the middle of the image, and the more serious the corrosion is toward the two sides. In addition, there is a curve with a porosity of 1 at the dissolution front, corresponding to cracks caused by dissolution (the porosity at the crack is 1). the

The above is only one of the embodiments of the utility model, so all equivalent changes or modifications made according to the structure, features and principles described in the utility model patent application scope are all included in the utility model patent application scope . the

Claims (1)

1. A cement-based material porosity distribution testing device based on industrial X-ray tomography, characterized in that it comprises: a plastic hose (5), a plastic test tube (4) and a vacuum suction device that are fixed with epoxy resin at the bottom , The two ends of the plastic hose (5) are respectively connected with a second rubber plug (7) and a third rubber plug (8), A first perforated rubber stopper (6) is provided on the test tube hole of the plastic test tube (4), Described vacuum suction device comprises conical flask (12), is provided with rubber stopper (11) on the bottleneck of conical flask (12), is connected with vacuum gauge (14) on conical flask (12), simultaneously On conical flask (12), be connected with vacuum pump (15) by first vacuum tube (13), on conical flask (12), also be connected with second vacuum tube (10) and conical flask (12) and second vacuum tube One end of (10) is connected, and the other end of second vacuum tube (10) is connected with the 4th opening rubber stopper (9), The third rubber plug (8) on the plastic hose (5) is connected to the fourth opening rubber plug (9), and the second rubber plug (7) is connected to the first opening when the vacuum pump (15) is working. A holed rubber plug (6) forms a negative pressure connection, and the second rubber plug (7) is separated from the first holed rubber plug (6) when the vacuum pump (15) stops working.

Images