A device and method for evaluating the uniformity of pouring of semi-flexible pavement grouting material

Abstract

The present invention relates to a device and method for evaluating the uniformity of pouring of a semi-flexible pavement grouting material. The device comprises a circular tube, a semicircular groove, a bottom plate and a side plate. The side plate is connected to the bottom plate to form an open container. Two mutually perpendicular semicircular grooves are arranged on the bottom plate panel, and the two ends thereof extend out of the bottom plate. Four vertical circular tubes are arranged outside the open container, and the part of the semicircular groove extending out of the container is connected to the bottom of the circular tube. The evaluation method utilizes the above device to divide the formed base asphalt mixture specimen into four equal-volume sector-shaped small specimens along the axial direction, and put them into the open container for a pouring test. The pouring unevenness U is calculated by testing the quality of the four small specimens before grouting and the connected porosity before and after grouting. The smaller U is, the better the pouring uniformity of the grouting material is. The present invention can accurately, efficiently and quantitatively evaluate the pouring uniformity of the grouting material, and has the advantages of simple operation method and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering material working performance testing, and in particular relates to a device and method for evaluating the pouring uniformity of a semi-flexible road grouting material. Background Art

[0002] Semi-flexible pavement is a new type of combined pavement, which mainly refers to the cement-based materials with high fluidity, micro-expansion and early strength poured into the macroporous matrix asphalt mixture. Semi-flexible pavement combines the advantages of cement concrete pavement and asphalt pavement, forming a unique new type of pavement material that is both rigid and flexible. Domestic and foreign road researchers believe that the uniformity of grouting is one of the key performances for the success of semi-flexible pavement. The uniformity of grouting is related to factors such as the uniformity of the matrix asphalt mixture, the fluidity technical indicators of the grouting, and construction machinery and tools. Relatively speaking, the influencing factors of construction machinery and tools are better controlled. Therefore, controlling the two important factors of the uniformity of the matrix asphalt mixture and the fluidity of the grouting is the key to ensuring the road performance of semi-flexible pavement.

[0003] In the existing specifications and test methods, the properties of grouting materials for semi-flexible pavements in the field of road engineering have been continuously enriched and developed through reference and innovation, such as the fluidity test method, strength test method, shrinkage performance test method (application number: 201920442416.7) and injection rate of grouting materials, which play an important role in the promotion and application of semi-flexible pavements. However, the fluidity test of grouting materials based on the flow cone flow method is derived from "GB / T 25182 Prestressed Duct Grouting Agent" and "JT / T 946 Prestressed Duct Grouting Agent for Highway Engineering", which are quite different from the working conditions of the internal pores of the semi-flexible pavement matrix asphalt mixture. At the same time, the injection rate test evaluation index fails to consider the problem of injection uniformity.

[0004] Therefore, the present invention provides a device and method for evaluating the uniformity of the injection of a semi-flexible pavement grouting material. The present invention comprehensively considers the influence of the variability of the internal pores of the base asphalt mixture on the injection of the grouting material, as well as the variability of the injection rate, and can accurately, efficiently and quantitatively evaluate the injection uniformity of the grouting material, and has the advantages of simple operation method and low cost. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for evaluating the uniformity of the injection of semi-flexible pavement grouting materials. The present invention can effectively solve the problems such as the influence of the variability of the internal pores of the base asphalt mixture on the injection of the grouting material and the variability of the injection rate, and realize accurate, efficient and quantitative evaluation of the injection uniformity of the grouting material, and has the advantages of simple operation method and low cost.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for evaluating the pouring uniformity of a semi-flexible pavement grouting material, the device comprising a round tube, a semi-circular groove, a side plate, and a bottom plate, wherein the round tube is made of a transparent material;

[0008] The lower edge of the side panel is vertically connected to the bottom plate along the edge of the bottom plate to form an open container; two mutually perpendicular semicircular grooves are arranged on the bottom plate panel, the semicircular grooves are concave, the intersection of the two semicircular grooves is the center of the bottom plate, and both ends thereof extend out of the bottom plate; four vertical circular tubes are arranged on the outside of the open container, the upper end of the circular tube is open, the bottom is connected to the end of the semicircular groove outside the container, and the part of the semicircular groove extending out of the container is connected to the bottom of the circular tube.

[0009] Preferably, the diameter of the circular tube is equal to the diameter of the semicircular groove, and the diameter ranges from 5 to 10 mm.

[0010] Preferably, the circular tube is provided with a scale, and the minimum scale value is 1 mL.

[0011] Preferably, the height of the round tube is consistent with the height of the side plate.

[0012] Preferably, the side panels are made of a soft and elastic material.

[0013] Preferably, the base plate is made of hard material.

[0014] Preferably, the bottom plate is circular or square.

[0015] An evaluation method for a semi-flexible pavement grouting material pouring uniformity evaluation device comprises the following steps:

[0016] Step 1: Weigh the mass of the formed dry base asphalt mixture specimen M Then the base asphalt mixture specimen is divided into four equal-volume sector-shaped small specimens along the axial direction, and the quality of each dry small specimen is tested in turn. m 1. m 2. m 3 and m 4 and connected porosity A 1. A 2. A 3 and A 4;

[0017] Step 2: Brush the release agent on the inner sides of the side panels and the bottom panel of the open container, then place the four small test pieces in the open container, and ensure that the four small test pieces are tightly spliced ​​according to the positions before cutting;

[0018] Step 3: Pour the prepared grouting material into the open container. After the liquid level in the round tube rises to the height of the small test piece and the liquid level is stable, stop grouting, scrape off the excess grouting material on the top surface of the four small test pieces, and maintain under standard conditions (temperature 20±2°C, relative humidity>95%) for the specified time;

[0019] Step 4: Take out the four small specimens that have been cured from the open container, and test the connected porosity of the four small specimens. a 1. a 2. a 3 and a 4. Calculate the grouting unevenness U by the mass of the base asphalt mixture specimen before grouting and the connected porosity before and after grouting. The smaller U is, the better the grouting uniformity is.

[0020] Preferably, the perfusion unevenness U in step 4 is calculated according to the following formula:

[0021] (9-1);

[0022] (9-2);

[0023] (9-3);

[0024] (9-4);

[0025] In formula (9-1), M is the mass of the dry base asphalt mixture specimen, m i ( i =1, 2, 3, 4) is the mass of each small specimen under dry conditions, A i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen under dry conditions, a i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen after pouring, S i ( i =1, 2, 3, 4) is the pouring void ratio of each small specimen, and the pouring void ratio of each small specimen is calculated by the mass of each small specimen before pouring and the connected void ratio of each small specimen before and after pouring S i ;

[0026] In formula (9-2), is the average pouring void ratio of the four small specimens, that is, the average pouring void ratio of the base asphalt mixture specimen;

[0027] In formula (9-3), U i ( i =1, 2, 3, 4) is the infusion unevenness of each small specimen. The variability of the infusion rate is characterized by calculating the standard deviation and coefficient of variation of the infusion void ratio of each small specimen.

[0028] In formula (9-4), U It is the sum of the pouring unevenness of the four small specimens, that is, the pouring unevenness of the base asphalt mixture specimen and the pouring unevenness U It can characterize the uniformity of the base asphalt mixture specimen, the fluidity of the grouting material and the uniformity of the injection rate, so as to evaluate the uniformity of the grouting material and the unevenness of the injection. U The smaller it is, the better the uniformity of the grouting material will be.

[0029] Compared with the prior art, the beneficial technical effects of the present invention are:

[0030] (1) The present invention relates to a device for evaluating the uniformity of grouting of a semi-flexible pavement grouting material. The side panels of the open container are made of a soft elastic material. When a specimen is placed in the open container, the side panels of the specimen can be in close contact with the side panels, with a small gap. No grouting material overflows during grouting, ensuring that the grouting material seeps from the surface and surroundings of the base asphalt mixture. At the same time, the bottom plate has a semicircular groove and is connected to an open circular tube to avoid air resistance during the grouting process, so that the slurry flows smoothly from the bottom of the specimen into the circular tube. The circular tube is made of a transparent material and is provided with a scale with a minimum scale of 1 mL. By using the principle of a communicating vessel, the grouting and flow of the grouting material to the specimen can be observed during grouting. By adjusting the shape and size of the bottom plate and the side panels, the test requirements of cylindrical and rectangular specimens can be met. The device has good adaptability. In short, the device more realistically simulates the way in which grouting material flows into the base asphalt mixture at the construction site.

[0031] (2) A semi-flexible pavement is a composite of a base asphalt mixture and a grouting material. The device and method for evaluating the uniformity of grouting material for a semi-flexible pavement described in the present invention divide the base asphalt mixture specimen into four small sector-shaped specimens of equal volume along the axial direction, pour the prepared grouting material into the base asphalt mixture, test the quality of the four small specimens before pouring and the connected porosity before and after pouring, calculate the pouring unevenness U, and obtain the pouring uniformity of the base asphalt mixture in four axial directions, thereby realizing the evaluation of the grouting material. Uniformity, the smaller the injection unevenness U, the better the injection uniformity of the grouting material. The adopted injection uniformity index takes into account the variability of the base asphalt mixture and the fluidity and injection rate of the grouting material, improves the test efficiency, and ensures the scientificity and reliability of the test results. According to the test results, the grouting material with good injection uniformity is selected to inject the base asphalt mixture, which is beneficial to extend the service life of the semi-flexible pavement and improve driving comfort and safety. The device and evaluation method are simple to operate, the test takes less time, the efficiency is high, the cost is low, and the test results are reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram when the bottom plate of the device of the present invention is circular;

[0033] Figure 2 It is a top view of the structure when the bottom plate of the device of the present invention is circular;

[0034] In the attached drawings, 1-circular tube, 2-semicircular groove, 3-side plate, 4-bottom plate, 5-base asphalt mixture specimen. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] A device for evaluating the pouring uniformity of a semi-flexible pavement grouting material, the device comprising a round tube 1, a semi-circular groove 2, a side plate 3, and a bottom plate 4, wherein the round tube 1 is made of a transparent material;

[0038] The lower edge of the side plate 3 is vertically connected to the bottom plate 4 along the edge of the bottom plate 4 to form an open container; two mutually perpendicular semicircular grooves 2 are arranged on the panel of the bottom plate 4, the semicircular groove 2 is concave, the intersection of the two semicircular grooves 2 is the center of the bottom plate 4, and both ends thereof extend out of the bottom plate 4, and four vertical circular tubes 1 are arranged on the outside of the open container, the upper end of the circular tube 1 is open, and the bottom is connected to the end of the semicircular groove 2 outside the container, and the part of the semicircular groove 2 extending out of the container is connected to the bottom of the circular tube 1, so as to avoid air resistance during the grouting process, so that the slurry flows smoothly from the bottom of the specimen into the circular tube 1;

[0039] The diameter of the circular tube 1 is equal to the diameter of the semicircular groove 2, and the diameter range is 5-10 mm. A scale is set on the circular tube 1, and the minimum scale value is 1 mL. The height of the circular tube 1 is consistent with the height of the side plate 3. By using the communicating vessel principle, the pouring and flow of the grouting material to the base asphalt mixture specimen 5 can be observed during pouring;

[0040] The side plate 3 is made of a soft elastic material. When the specimen is placed in an open container, the side of the specimen can be in close contact with the side plate, and no grouting material overflows during grouting, ensuring that the grouting material seeps from the surface and surroundings of the base asphalt mixture specimen 5.

[0041] The bottom plate 4 is a circular structure made of hard material. The side plate 3 and the bottom plate 4 form a cylindrical open container. In addition to being circular, the bottom plate 4 can also be square. By adjusting the shape and size of the bottom plate 4 and the side plate 3, the test requirements of cylindrical specimens and rectangular specimens can be met.

[0042] Example 2

[0043] This embodiment provides a method for evaluating the pouring uniformity of a semi-flexible pavement grouting material using the device of embodiment 1, comprising the following steps:

[0044] Step 1: First weigh the mass M of the formed dry base asphalt mixture specimen 5, then divide the base asphalt mixture specimen 5 into four equal-volume sector-shaped small specimens along the axial direction, and test the mass of each dry small specimen in turn. m 1. m 2. m 3 and m 4 and its connected porosity A 1. A 2. A 3 and A 4;

[0045] Step 2: Brush the release agent on the inner side of the side plate 3 and the inner side of the bottom plate 4 of the open container, and then place the four small test pieces in the open container, and ensure that the four small test pieces are tightly spliced ​​according to the positions before cutting;

[0046] Step 3: Pour the prepared grouting material from the top of the open container. After the liquid level of the four round tubes 1 rises to the height of the small test pieces and the liquid level is stable, stop grouting, scrape off the excess grouting material on the top surface of the four small test pieces, and maintain under standard conditions (temperature 20±2°C, relative humidity>95%) for the specified time;

[0047] Step 4: Take out the four small specimens that have been cured from the open container, and test the connected porosity of the four small specimens. a 1. a 2. a 3 and a 4. Calculate the unevenness of grouting by the mass of the base asphalt mixture specimen 5 before grouting and the connected void ratio before and after grouting U , the smaller U is, the better the uniformity of the grouting material is.

[0048] The unevenness of the perfusion in step 4 U Calculate according to the following formula:

[0049] (9-1);

[0050] (9-2);

[0051] (9-3);

[0052] (9-4);

[0053] In formula (9-1): M is the mass of the dry base asphalt mixture specimen 5, m i ( i =1, 2, 3, 4) is the mass of each small specimen under dry conditions, A i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen under dry conditions, a i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen after pouring, S i ( i =1, 2, 3, 4) is the pouring void ratio of each small specimen, and the pouring void ratio of each small specimen is calculated by the mass of each small specimen before pouring and the connected void ratio of each small specimen before and after pouring S i ;

[0054] In formula (9-2), is the average infusion void ratio of the four small specimens, i.e. the average infusion void ratio of the base asphalt mixture specimen 5;

[0055] In formula (9-3), U i ( i =1, 2, 3, 4) is the infusion unevenness of each small specimen. The variability of the infusion rate is characterized by calculating the standard deviation and coefficient of variation of the infusion void ratio of each small specimen.

[0056] In formula (9-4), U It is the sum of the pouring unevenness of the four small specimens, that is, the pouring unevenness of the base asphalt mixture specimen and the pouring unevenness U It can characterize the uniformity of the base asphalt mixture specimen 5, the fluidity of the grouting material and the uniformity of the injection rate, thereby realizing the evaluation of the uniformity of the grouting material and the injection unevenness. U The smaller it is, the better the uniformity of the grouting material will be.

[0057] Example 3

[0058] In this embodiment, a Φ101.6 mm×63.5 mm cylindrical specimen was formed according to the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E 20-2011) T0702-2011 to prepare a base asphalt mixture specimen 5. The SFAC-13 gradation of the base asphalt mixture specimen 5 is shown in Table 1, the asphalt-stone ratio is 3.5%, and the target porosity is 28%.

[0059] Table 1 SFAC-13 gradation

[0060]

[0061] The following steps are implemented using the semi-flexible pavement grouting material pouring uniformity evaluation device and evaluation method of the above-mentioned embodiment 1 and embodiment 2:

[0062] In step 1, the mass of the formed dry base asphalt mixture specimen 5 is measured to be M = 1051.3 g, and then the base asphalt mixture specimen 5 is divided into four small specimens of equal volume along the axial direction, and the mass of each dry small specimen is measured to be m 1 = 269.7g, m 2 = 255.6g, m 3 = 255.9 g and m 4 = 270.1 g, and the connected void ratio measured by the density test of compacted asphalt mixture according to the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E 20-2011) A 1=22.4%, A 2 = 20.7%, A3 = 21.5% and A 4 = 22.1%;

[0063] After grouting and curing in steps 2 and 3, the connected porosity of the four small specimens measured in step 4 is a 1=1.4%, a 2=1.7%, a 3 = 1.6% and a 4=1.5%. Substitute the above test data into formula (9-1), formula (9-2), formula (9-3), and formula (9-4) to calculate the perfusion unevenness. U =1.2.

[0064] Example 4

[0065] This embodiment adopts the same semi-flexible pavement grouting material injection uniformity evaluation device and evaluation method as in Example 3, and prepares the SFAC-13 gradation of the base asphalt mixture specimen 5 as shown in Table 2, with an asphalt-stone ratio of 3.8% and a target porosity of 24%.

[0066] Table 2 SFAC-13 grading

[0067]

[0068] The following steps are implemented using the above-mentioned semi-flexible pavement grouting material pouring uniformity evaluation device and evaluation method:

[0069] In step 1, the mass M of the dry base asphalt mixture specimen 5 is measured to be 1087.3 g, and then the base asphalt mixture specimen 5 is divided into four small specimens of equal volume along the axial direction, and the mass of each dry small specimen is measured to be m 1 = 262.2g, m 2 = 276.4g, m 3 = 282.6 g and m 4 = 266.1 g, and the connected void ratio measured by the density test of compacted asphalt mixture according to the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E 20-2011) A 1=16.5%, A 2=18.4%, A 3 = 18.1% and A 4=16.5%;

[0070] After grouting and curing in steps 2 and 3, the connected porosity of the four small specimens measured in step 4 is a 1=3.4%, a 2=3.3%, a 3 = 3.1% and a4=3.3%. Substitute the above test data into formula (9-1), formula (9-2), formula (9-3), and formula (9-4) to calculate the perfusion unevenness. U =2.1.

[0071] The perfusion unevenness of Example 3 and Example 4 U The calculated value of the evaluation results shows that the grouting uniformity of Example 3 is better than that of Example 4.

[0072] The method for evaluating the uniformity of the pouring of semi-flexible pavement grouting materials proposed in the present invention is based on the designed device and the test data of actual semi-flexible pavement materials, and is reliable. In summary, the design ideas of the device and the evaluation method of the present invention are scientific and reasonable, simple and easy to implement, and the test results are true and reliable.

[0073] All parts of the embodiments of the present invention that are not described in detail are the same as the prior art or can be implemented by using the prior art.

[0074] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for evaluating the uniformity of pouring of semi-flexible pavement grouting material, characterized in that: The device comprises a circular tube (1), a semicircular groove (2), a side plate (3), and a bottom plate (4); the circular tube (1) is made of a transparent material; The lower edge of the side plate (3) is vertically connected to the bottom plate (4) along the edge of the bottom plate (4) to form an open container; two mutually perpendicular semicircular grooves (2) are arranged on the panel of the bottom plate (4); the semicircular grooves (2) are concave, the intersection of the two semicircular grooves (2) is the center of the bottom plate (4), and the two ends thereof extend out of the bottom plate (4); four vertical circular tubes (1) are arranged on the outside of the open container; the upper ends of the circular tubes (1) are open, and the bottoms are connected to the ends of the semicircular grooves (2) outside the container; the portions of the semicircular grooves (2) extending out of the container are connected to the bottoms of the circular tubes (1); The device for evaluating the pouring uniformity of the semi-flexible pavement grouting material is used for the method for evaluating the pouring uniformity of the semi-flexible pavement grouting material, and the method comprises the following steps: Step 1: First weigh the mass M of the formed dry base asphalt mixture specimen (5), then divide the base asphalt mixture specimen (5) into four equal-volume sector-shaped small specimens along the axial direction, and test the mass of each dry small specimen in turn. m 1. m 2. m 3 and m 4 and its connected porosity A 1. A 2. A 3 and A 4; Step 2: Brush a release agent on the inner side of the side plate (3) and the inner side of the bottom plate (4) of the open container, then place the four small test pieces in the open container, and ensure that the four small test pieces are tightly spliced ​​according to the positions before cutting; Step 3: Pour the prepared grouting material from the top of the open container. When the liquid level in the four round tubes (1) rises to the height of the small test pieces and the liquid level is stable, stop grouting, scrape off the excess grouting material on the top surface of the four small test pieces, and maintain under standard conditions (temperature 20±2°C, relative humidity>95%) for a specified time; Step 4: Take out the four small specimens that have been cured from the open container, and test the connected porosity of the four small specimens. a 1. a 2. a 3 and a 4. Calculate the grouting unevenness by the mass of the base asphalt mixture specimen (5) before grouting and the connected void ratio before and after grouting U , the smaller U is, the better the uniformity of the grouting material is.

2. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The diameter of the circular tube (1) is equal to the diameter of the semicircular groove (2), and the diameter ranges from 5 to 10 mm.

3. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The circular tube (1) is provided with a scale, and the minimum scale value is 1 mL.

4. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The height of the circular tube (1) is consistent with the height of the side plate (3).

5. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The side panels (3) are made of a soft material with elasticity.

6. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The base plate (4) is made of a hard material.

7. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The bottom plate (4) is circular or square.

8. The device for evaluating the uniformity of pouring of semi-flexible pavement grouting material according to claim 1, characterized in that: The unevenness of the perfusion in step 4 U Calculate according to the following formula: （9-1）； （9-2）； （9-3）； （9-4）； In formula (9-1): M is the mass of the dry base asphalt mixture specimen, m i ( i =1, 2, 3, 4) is the mass of each small specimen under dry conditions, A i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen under dry conditions, a i ( i =1, 2, 3, 4) is the interconnected porosity of each small specimen after pouring, S i ( i =1, 2, 3, 4) is the pouring void ratio of each small specimen, and the pouring void ratio of each small specimen is calculated by the mass of each small specimen before pouring and the connected void ratio of each small specimen before and after pouring S i ; In formula (9-2), is the average injection void ratio of the four small specimens, i.e. the average injection void ratio of the base asphalt mixture specimen (5); In formula (9-3), U i ( i =1, 2, 3, 4) is the infusion unevenness of each small specimen. The variability of the infusion rate is characterized by calculating the standard deviation and coefficient of variation of the infusion void ratio of each small specimen. In formula (9-4), U It is the sum of the pouring unevenness of the four small specimens, that is, the pouring unevenness of the base asphalt mixture specimen and the pouring unevenness U It can characterize the uniformity of the base asphalt mixture specimen, the fluidity of the grouting material and the uniformity of the injection rate, so as to evaluate the uniformity of the grouting material and the unevenness of the injection. U The smaller it is, the more uniform the grouting material will be.

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