Compaction test method of asphalt cold patch material

Abstract

The invention relates to the field of road engineering, in particular to a compaction test method of an asphalt cold patch material, which comprises the following steps: setting parameters of a rotary compactor according to the compaction degree of a to-be-tested asphalt pavement, and calibrating a rotation angle parameter; preparing an asphalt test piece through a space enclosed by a test mold and a pressure plate of the rotary compactor, compacting the asphalt test piece, and measuring the mass m4 of the asphalt test piece; drilling a notch from the center of the top of the asphalt test piece; filling the gap of the asphalt test piece with an asphalt cold-patch material to be tested to obtain an asphalt cold-patch test piece; compacting the asphalt cold-patch test piece by using a rotary compactor, and measuring the mass m5 of the asphalt cold-patch test piece; preparing the asphalt cold patch material according to at least two groups of parallel tests for calculating the theoretical maximum relative density B of the asphalt cold patch material; calculating the actual density A of the compacted cold patch material in the asphalt cold patch test piece by using the difference between m5 and m4; the compaction degree G is obtained according to the ratio of A to B; the problems that an evaluation result of an existing compaction test method cannot truly reflect the actual construction condition and the test cost is high are solved.

Description

Technical Field

[0001] The invention relates to the field of road engineering, in particular to a compaction test method for asphalt cold patch material. Background Art

[0002] Asphalt pavement is an important type of pavement widely used in the field of road engineering at this stage. The quality of asphalt pavement affects all aspects of road performance and service level. As the traffic load of asphalt pavement becomes heavier and the traffic volume increases significantly, some of the early paved asphalt pavements have defects such as potholes, cracks, rutting and loose peeling, which not only affect the service life of the pavement, but also increase the hidden dangers of vehicle driving safety; and the cold patch method is one of the conventional repair methods for these defects. It uses solvent-based asphalt cold patch material or emulsion-based asphalt cold patch material for repair, which has the advantages of not being affected by weather, simple construction, energy saving and environmental protection.

[0003] Therefore, it is often necessary to study the comprehensive performance of asphalt cold patch materials, continuously improve the repair effect of cold-patch asphalt pavements, and extend the service life of asphalt pavements. Among them, testing the compaction of asphalt cold patch materials is an important part of evaluating the comprehensive performance of cold patch materials; the better the compaction of the cold patch material, the lower the porosity in the mixture after the asphalt pavement is repaired, the more difficult it is for water to enter the mixture, the better the waterproofness, and the stronger the durability; while the worse the compaction of the cold patch material, the weaker the ability to resist water damage in the later stage of repair, and the more likely the asphalt pavement will reappear the original disease.

[0004] The currently commonly used asphalt cold patch material compaction test method uses a specimen that is completely prepared from cold patch material. The cold patch material is directly compacted into shape by a compaction instrument, and then the density of the compacted specimen is calculated. At the same time, based on the test result of the maximum theoretical density, the ratio of the two is calculated to obtain the density, thereby evaluating the compaction of the cold patch material.

[0005] However, the currently used cold patch material compaction test method has some shortcomings:

[0006] (1) The purpose of asphalt cold patch material is to repair defects such as potholes on the original asphalt pavement. Taking potholes as an example, during the actual compaction process of the cold patch material, the cold patch material is in contact with the original asphalt pavement mixture at the interface around the pothole. However, when using the current compaction test method, the asphalt cold patch material is actually in contact with the test mold (i.e., the carrier of the test piece prepared by the cold patch material on the rotary compactor). During the compaction process, the test mold and the test piece interact with each other at the boundary (i.e., the test piece is resisted by the test mold during the compaction process to prevent deformation). It is impossible to reflect the impact of the original asphalt pavement at the interface around the pothole on the compaction of the cold patch material in actual construction, resulting in a large error between the results of the indoor compaction test and the compaction effect in actual construction. Therefore, the compaction of the asphalt cold patch material cannot be accurately evaluated.

[0007] (2) In order to improve the performance of the asphalt cold patch material currently being studied, other additives are often added to it, and the cost of these modifiers and additives is relatively high. When the currently used cold patch material compaction test method is adopted, the entire specimen is prepared entirely from asphalt cold patch material, resulting in the need to use more asphalt cold patch material, and therefore more additives or cold patch agents, which will increase the cost and cause a waste of resources. Summary of the invention

[0008] In view of the above-mentioned defects, the purpose of the present invention is to propose a compaction test method for asphalt cold patch material to solve the problem that the evaluation results of the current compaction test method cannot truly reflect the actual construction situation and the test cost is high.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] A method for testing the compactability of asphalt cold patch material comprises the following steps:

[0011] A1: According to the compaction degree of the asphalt pavement to be tested, set the parameters of the rotary compactor, and start the rotary compactor multiple times to measure the internal rotation angle. When the angle error in multiple measurements is less than 0.02°, take the average of the multiple measured angles and set it as the rotation angle parameter of the rotary compactor.

[0012] A2: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the rotary compactor, and use the rotary compactor to compact the asphalt specimens, and measure the mass of the asphalt specimens, which is recorded as m4;

[0013] A3: Drill a notch from the top center of the asphalt specimen;

[0014] A4: Fill the gap of the asphalt test piece with the asphalt cold patch material to obtain an asphalt cold patch test piece;

[0015] A5: Use a rotary compactor to compact the asphalt cold patch specimen and measure the mass of the asphalt cold patch specimen, recorded as m5;

[0016] A6: Prepare asphalt cold patch material according to at least two sets of parallel tests to calculate the theoretical maximum relative density B of asphalt cold patch material;

[0017] A7: Use the difference between m5 and m4 to calculate the actual density A of the compacted cold patch material in the asphalt cold patch specimen;

[0018] A8: The compaction degree G is obtained by using the ratio of the actual density A and the theoretical maximum relative density B, G = A / B.

[0019] Furthermore, in step A3, the volume of the notch is less than or equal to one half of the total volume of the asphalt specimen.

[0020] Furthermore, in step A3, the shape of the notch is the same as the shape of the asphalt test piece.

[0021] Furthermore, in the step A2, a cylindrical test mold is used as the test mold; in the step A3, a cylindrical drill bit is used for drilling the notch corresponding to the shape of the cylindrical test mold.

[0022] Furthermore, in step A7, m5 and m4 are substituted into the formula Where h is the depth of the notch and d is the diameter of the notch; the actual density A of the compacted cold patch material is obtained.

[0023] Furthermore, the step A2 comprises the following steps:

[0024] A21: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the gyratory compactor, and compact the asphalt specimens using the gyratory compactor;

[0025] A22: Repeatedly humidify, dry and roll the top surface of the asphalt specimen within a preset time, and then measure the mass of the asphalt specimen, recorded as m4.

[0026] Furthermore, the step A1 further comprises: when the internal rotation angle includes a top internal rotation angle and a bottom internal rotation angle, starting the rotary compactor multiple times to measure the top internal rotation angle and the bottom internal rotation angle respectively;

[0027] The average of the top inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the top inner rotation angle parameter of the gyratory compactor;

[0028] The average of the bottom inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the bottom inner rotation angle parameter of the gyratory compactor.

[0029] Furthermore, in step A6, the theoretical maximum relative density B of the asphalt cold patch material is calculated using a vacuum method.

[0030] Furthermore, the step A6 includes the following sub-steps:

[0031] A61: After the prepared asphalt cold patch material is cured at room temperature, the asphalt cold patch material is repeatedly turned over and mixed to ensure that the coarse aggregate is not crushed, the fine aggregate is dispersed to less than 6.4mm, and the asphalt cold patch material does not adhere;

[0032] A62: Group the asphalt cold patch materials equally into at least two parallel test groups, place each group of asphalt cold patch materials into a negative pressure container, and measure the mass of each group of negative pressure containers containing asphalt cold patch materials, recorded as m1;

[0033] A63: Pour water into the negative pressure container so that the asphalt cold patch material is completely submerged and the water level is higher than the surface of the asphalt cold patch material, and add a surfactant to the water to remove bubbles in the water;

[0034] A64: Use negative pressure and vibration to fully remove the air in each group of asphalt cold patch material, measure the mass of water in each group of negative pressure containers containing asphalt cold patch material, and record it as m2;

[0035] A65: Pour out the cold patch material in each group of negative pressure containers respectively, and measure the mass of water in the negative pressure container, recorded as m3;

[0036] A66: Substitute m1, m2 and m3 into the formula B = m1 / [m1-(m2-m3)] to obtain the theoretical maximum relative density B of each group of asphalt cold patch material. Take the average of the theoretical maximum relative density B of each group as the final theoretical maximum relative density B.

[0037] The technical solution provided by the present invention may include the following beneficial effects: in view of the problem that the evaluation results of the current asphalt cold patch material compaction test method cannot truly reflect the actual construction situation, according to the compaction degree of the asphalt pavement to be tested, the rotation angle parameter is calibrated through step A1, so that the rotary compactor makes the test piece evenly stressed during the subsequent compaction process, so that the density distribution is uniform, and the compaction scene of the asphalt pavement after construction (i.e., asphalt test piece) or the cold-patch asphalt pavement (i.e., asphalt cold patch test piece) can be truly simulated; through step A2, the asphalt test piece is prepared and compacted by using the test mold and the pressure plate of the rotary compactor to enclose the space, and there is no need to use a special mold to pour hot-mix asphalt mixture to prepare the asphalt test piece, and then demold and compact it using the rotary compactor, thereby reducing the asphalt test piece preparation steps, and the asphalt test piece prepared by the test mold of the rotary compactor is most consistent with the test mold, there is no gap at the joint, and it will not be over-compressed; and During compaction, the pressure head is directly driven to squeeze into the assembly surrounded by the test mold and the pressure plate to compact the asphalt test piece, which is easy to operate; through step A3, a notch is drilled from the top center of the asphalt test piece to simulate the disease phenomenon of the asphalt pavement. At the same time, because the notch is located in the top center of the asphalt test piece, when the asphalt cold patch material to be tested is filled with the notch in step A4, there is an asphalt layer between the asphalt cold patch material and the test mold, and the asphalt cold patch material does not contact the test mold, so as to avoid the asphalt cold patch material compaction process being blocked by the test mold; on the basis of the above, through steps A6 to A8, the compaction degree G that truly reflects the compaction state of the asphalt cold patch material in the actual construction scene can be obtained, which is used to evaluate the comprehensive performance of the asphalt cold patch material (usually the larger the compaction degree G, the better, and the larger the closer to the ideal state), compared with the current compaction test method, the compaction degree G has a very small error, which is basically consistent with the multiple test results of the asphalt cold patch material. More importantly, the asphalt test piece no longer needs to be prepared entirely with asphalt cold patch material, which greatly reduces additives or cold patch agents and reduces test costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention is a flowchart of a method for testing the compactability of asphalt cold patch material according to one embodiment of the present invention.

[0039] Figure 2 It is a schematic structural diagram of an asphalt cold patch specimen in one embodiment of the present invention.

[0040] Among them: asphalt cold patch specimen 1, gap 2. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0042] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of the features, and are used to distinguish and describe features, without distinction of order or importance.

[0043] In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0044] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0045] Combine the following Figure 1 to Figure 2 , describes a compaction test method for asphalt cold patch material in an embodiment of the present invention.

[0046] A method for testing the compactability of asphalt cold patch material comprises the following steps:

[0047] A1: According to the compaction degree of the asphalt pavement to be tested, set the parameters of the rotary compactor, and start the rotary compactor multiple times to measure the internal rotation angle. When the angle error in multiple measurements is less than 0.02°, take the average of the multiple measured angles and set it as the rotation angle parameter of the rotary compactor.

[0048] A2: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the rotary compactor, and use the rotary compactor to compact the asphalt specimens, and measure the mass of the asphalt specimens, which is recorded as m4;

[0049] A3: Drill a notch 2 from the top center of the asphalt specimen;

[0050] A4: Fill the gap 2 of the asphalt specimen with the asphalt cold patch material to be tested to obtain an asphalt cold patch specimen 1;

[0051] A5: Use a rotary compactor to compact the asphalt cold patch specimen 1 and measure the mass of the asphalt cold patch specimen 1, recorded as m5;

[0052] A6: Prepare asphalt cold patch material according to at least two sets of parallel tests to calculate the theoretical maximum relative density B of asphalt cold patch material;

[0053] A7: Calculate the actual density A of the compacted cold patch material in asphalt cold patch specimen 1 using the difference between m5 and m4;

[0054] A8: The compaction degree G is obtained by using the ratio of the actual density A and the theoretical maximum relative density B, G = A / B.

[0055] The present invention provides a method for testing the compactability of asphalt cold patch material. Figures 1 to 2As shown, in view of the problem that the evaluation results of the current asphalt cold patch material compaction test method cannot truly reflect the actual construction situation, according to the compaction degree of the asphalt pavement to be tested, the rotation angle parameters are calibrated through step A1, so that the rotary compactor can make the test piece evenly stressed in the subsequent compaction process, so that the density distribution is uniform, and it can truly simulate the compaction scene of the asphalt pavement after construction (i.e., asphalt test piece) or the cold-patched asphalt pavement (i.e., asphalt cold patch test piece); through step A2, the asphalt test piece is prepared and compacted by using the test mold and the pressure plate of the rotary compactor, and there is no need to use a special mold to pour hot-mix asphalt mixture to prepare the asphalt test piece, and then demold and compact it using the rotary compactor, thereby reducing the steps of asphalt test piece preparation, and the asphalt test piece prepared by the test mold of the rotary compactor is most consistent with the test mold, there is no gap at the joint, and it will not be over-compressed; and when compacting, it is directly driven The pressure head is pressed into the assembly surrounded by the test mold and the pressure plate to compact the asphalt test piece, which is easy to operate; through step A3, a gap 2 is drilled from the top center of the asphalt test piece to simulate the disease phenomenon of the asphalt pavement. At the same time, because the gap 2 is located in the top center of the asphalt test piece, when the gap 2 in step A4 fills the asphalt cold patch material to be tested, there is an asphalt layer between the asphalt cold patch material and the test mold, and the asphalt cold patch material does not contact the test mold, so as to avoid the asphalt cold patch material compaction process being blocked by the test mold; on the basis of the above, through steps A6 to A8, the compaction degree G that truly reflects the compaction state of the asphalt cold patch material in the actual construction scene can be obtained, which is used to evaluate the comprehensive performance of the asphalt cold patch material (usually the larger the compaction degree G, the better, and the larger the closer to the ideal state), compared with the current compaction test method, the compaction degree G has a very small error, which is basically consistent with the multiple test results of the asphalt cold patch material. More importantly, the asphalt test piece no longer needs to be prepared entirely with asphalt cold patch material, which greatly reduces additives or cold patch agents and reduces test costs.

[0056] It should be noted that the specific implementation methods of each step can be as follows (one of the embodiments):

[0057] A1: Prepare the rotary compactor and determine the test conditions for calibrating the instrument: the vertical pressure of the loading device is 600kPa, and the compaction speed is 30r / min; clean the surface of the test mold, the upper platen of the instrument, and the internal rotation angle measuring device, and heat the test mold in a 150℃ oven for 45min; set the number of rotations to 140 times; assemble the internal rotation angle measuring device, put it into the test mold, position the instrument probe or reference base, and then put the test mold into the rotary compactor; start rotary compaction, and control the conditions for rotation as follows: The generated eccentricity e is 22 mm, and the torque M (i.e., e×F) is 466.5 N·m; after rotating to the set number of times, stop compacting, and after the upper pressure head rises to a certain height, take out the internal rotation angle measuring device and record the test results; adjust the position of the internal rotation angle measuring device, and repeat the above steps 3 times (if the angle difference of the internal rotation angle is greater than 0.02°, the test must be repeated). When the angle errors in the three measurements are all less than 0.02°, take the average angle of the corresponding three internal rotation angles as the final internal rotation angle.

[0058] A2: First, weigh the stone and mineral powder of each particle size according to the designed gradation, and weigh the asphalt according to the designed amount. The specific types and amounts of the above materials vary depending on the design of the mixture ratio; then prepare the common hot-mix asphalt mixture, set the temperature of the mixing pot to 185℃, and after the mixing pot reaches the specified temperature, add the stone and stir for 30s; then add the mineral powder and stir for 60s; then add the asphalt and stir for 90s to obtain the hot-mix asphalt mixture. Pour the mixed hot-mix asphalt mixture from the mixing pot and place it on an iron plate for easy access. Wipe the test mold and the pressure plate with a brush dipped in butter or lubricating oil, and place them together in a 185℃ oven at a constant temperature for 45 minutes. Evenly weigh the mixture mass required to prepare an asphalt specimen from the mixed hot-mix asphalt mixture. Take the example of a rotary compactor with the platen at the bottom and the test mold as a cylinder sleeved on the platen (there are many combinations of the test mold and the platen), place a round piece of paper on the platen to prevent the asphalt from sticking to the platen, assemble the test mold and the platen (enclose them), quickly pour the weighed hot-mix asphalt mixture into the test mold, level the surface, and then cover the top with a round piece of paper. Place the test mold containing the hot-mix asphalt mixture into the rotary compactor, rotate the pressure head above the test mold, and start the rotary compactor to compact the inside of the test mold. When the rotary compactor stops running, raise the rotary pressure head, take out the test mold and the platen containing the hot-mix asphalt mixture specimen as a whole, separate the platen, and then peel off the round pieces of paper on the upper and lower sides of the specimen in the test mold to obtain the asphalt specimen made of the hot-mix asphalt mixture.

[0059] Turn off the rotary compactor and maintain the compacted asphalt specimen together with the test mold at room temperature for 2 weeks to simulate the changes of the original asphalt pavement over time; after 2 weeks, weigh the asphalt specimen (or the mass of the asphalt specimen together with the test mold) and record it as m4.

[0060] A3: Use a drill to drill a notch 2 from the top center of the asphalt specimen, and keep the remaining part to simulate the original asphalt pavement with defects (such as potholes).

[0061] A4: Prepare the materials for the asphalt cold patch material to be studied, including: (1) weighing the stone and mineral powder of each particle size according to the designed gradation; (2) weighing the asphalt according to the designed amount; (3) weighing the additives used according to the design requirements, such as water-based epoxy resin, polyurethane, etc. (Depending on the specific cold patch material composition design, demulsifiers, water and other materials can be prepared separately. At the same time, the specific types and amounts of various materials vary depending on the different cold patch material mix designs.)

[0062] Preparation of asphalt cold patch material: set the temperature of the mixing pot to 25°C, add stone, stir for 50s; then add mineral powder, stir for 50s; then add asphalt, stir for 50s; finally add additives, stir for 50s to obtain the asphalt cold patch material. (In this step, demulsifier, water and other materials can be added according to the specific cold patch material composition design. At the same time, the order of adding various materials only needs to follow the first three steps of adding stone, mineral powder, and asphalt. The order of adding other materials to the mixing pot can be customized according to the specific design plan.) Pour the mixed cold patch material from the mixing pot and place it on an iron plate for easy access; then fill the gap 2 with the asphalt cold patch material to obtain the asphalt cold patch specimen 1.

[0063] A5: The following compaction and measurement processes are the same as step A2. The asphalt cold patch specimen 1 is compacted and the mass m5 of the asphalt cold patch specimen 1 is measured.

[0064] A6: According to the currently commonly used theoretical maximum relative density B test method, asphalt cold patch material should be prepared according to at least two groups of parallel tests to calculate the theoretical maximum relative density B of the asphalt cold patch material, so as to improve the accuracy of the theoretical maximum relative density B.

[0065] A7: According to the density formula, the difference between m5 and m4 can be used to calculate the actual density A of the compacted cold patch material in the asphalt cold patch specimen 1.

[0066] A8: The compaction degree G is obtained by using the ratio of the actual density A and the theoretical maximum relative density B, G = A / B.

[0067] Furthermore, in step A3, the volume of the gap 2 is less than or equal to half of the total volume of the asphalt specimen.

[0068] In this embodiment, the volume of the gap 2 is less than or equal to one half of the total volume of the asphalt specimen, so that there are enough asphalt layers to buffer between the test mold and the asphalt cold patch layer, ensuring that the fusion between the asphalt layer and the asphalt cold patch layer during the compaction process reflects the actual construction scene, improves the test accuracy, and can also reduce the related usage of asphalt cold patch material and reduce the test cost.

[0069] Furthermore, in step A3, the shape of the notch 2 is the same as the shape of the asphalt test piece.

[0070] In this embodiment, the shape of the notch 2 is the same as the shape of the asphalt test piece, which can ensure that the asphalt cold patch layer is evenly stressed when the test mold acts on the asphalt layer during compaction, further reducing factors that affect the authenticity of the test. More importantly, the notch 2 with the same shape makes it easier to accurately fill the asphalt cold patch material, reducing the generation of gaps and uneven areas, and the notches of the same shape make the force distribution during compaction more uniform, which is conducive to the good combination of the asphalt cold patch layer and the asphalt layer.

[0071] Furthermore, in step A2, a cylindrical test mold is used as the test mold; in step A3, a cylindrical drill bit is used for drilling the notch 2 corresponding to the shape of the cylindrical test mold.

[0072] In this embodiment, based on the fact that the shape of the notch 2 and the shape of the asphalt test piece must be the same, taking into account the commonly used test mold shape of the rotary compactor and the shape of the drill bit used in daily life, it is preferred that both are cylindrical, which is a common regular shape and does not require additional customization, thereby reducing test costs and helping to reduce complex operations during drilling and filling, thereby improving test efficiency.

[0073] Furthermore, in step A7, substitute m5 and m4 into the formula Where h is the depth of notch 2, and d is the diameter of notch 2; the actual density A of the compacted cold patch material is obtained.

[0074] In this embodiment, based on the fact that the shape of the notch 2 and the shape of the asphalt test piece are both cylindrical, the calculation formula for the actual density A is:

[0075] Further, step A2 includes the following steps:

[0076] A21: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the gyratory compactor, and compact the asphalt specimens using the gyratory compactor;

[0077] A22: Repeatedly humidify, dry and roll the top surface of the asphalt specimen within a preset time, and then measure the mass of the asphalt specimen, recorded as m4.

[0078] In this embodiment, the top surface of the asphalt specimen is repeatedly humidified, dried and rolled to simulate the environmental factors such as rain scouring, sun exposure and vehicle rolling that the actual road experiences during use; this step can make the surface of the asphalt specimen closer to the road conditions under actual use, and prepare asphalt specimens that are closer to the actual road conditions, thereby improving the accuracy and reliability of the subsequent cold patch material compaction test results. This is of great significance for evaluating the actual application effect of cold patch materials, and can provide more reliable data support for road repair and maintenance. Therefore, measuring the quality of the asphalt specimen after the above treatment can more accurately reflect the performance of the asphalt pavement under actual use.

[0079] Furthermore, step A1 further comprises: when the internal rotation angle includes a top internal rotation angle and a bottom internal rotation angle, starting the rotary compactor multiple times to measure the top internal rotation angle and the bottom internal rotation angle respectively;

[0080] The average of the top inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the top inner rotation angle parameter of the gyratory compactor;

[0081] The average of the bottom inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the bottom inner rotation angle parameter of the gyratory compactor.

[0082] In this embodiment, when the internal rotation angle of the rotary compactor includes the top internal rotation angle and the bottom internal rotation angle, they need to be calibrated at the same time. If the errors of the internal rotation angles at the bottom and the top are large, the asphalt specimen or the asphalt cold-patch specimen 1 may be subjected to uneven compaction force, which will cause uneven density distribution inside the asphalt specimen or the asphalt cold-patch specimen 1, and cannot reflect the compaction effect under actual construction conditions.

[0083] Furthermore, in step A6, the vacuum method is used to calculate the theoretical maximum relative density B of the asphalt cold patch material.

[0084] In this embodiment, in order to improve the compatibility of the compaction test method and match the calculation of all types of asphalt cold patch materials, the vacuum method is preferably used to calculate the theoretical maximum relative density B of the asphalt cold patch material. Because in the commonly used theoretical maximum relative density calculation method:

[0085] (1) The solvent method is mainly applicable to asphalt mixture specimens with a high water absorption rate, such as asphalt gravel mixture and large-void permeable open-graded asphalt mixture specimens. This method is more suitable for mixture specimens with a large void ratio because it can accurately measure the maximum theoretical relative density of the asphalt mixture. However, for various asphalt mixture specimens with a water absorption rate not exceeding 2%, the solvent method is not very applicable because the water absorption of such specimens is relatively low and the use of the solvent method may lead to inaccurate measurement results.

[0086] (2) Surface dry method: It is mainly applicable to the determination of the gross volume relative density or gross volume density of various asphalt mixture specimens with a water absorption rate not exceeding 2%, including Type I or denser Type II asphalt concrete, anti-skid surface mixture, and asphalt mastic crushed stone mixture (SMA) specimens. This method is applicable to the calculation of various volumetric indicators of asphalt mixture specimens, such as the void ratio and mineral gap ratio. However, for asphalt mixture specimens with a water absorption rate greater than 2%, the surface dry method is no longer applicable because such specimens have a large water absorption rate and the use of the surface dry method may result in inaccurate measurement results.

[0087] However, the vacuum method can solve the problems existing in the solvent method and the surface drying method.

[0088] Furthermore, step A6 includes the following sub-steps:

[0089] A61: After the prepared asphalt cold patch material is cured at room temperature, the asphalt cold patch material is repeatedly turned over and mixed to ensure that the coarse aggregate is not crushed, the fine aggregate is dispersed to less than 6.4mm, and the asphalt cold patch material does not adhere;

[0090] A62: Group the asphalt cold patch materials equally into at least two parallel test groups, place each group of asphalt cold patch materials into a negative pressure container, and measure the mass of each group of negative pressure containers containing asphalt cold patch materials, recorded as m1;

[0091] A63: Pour water into the negative pressure container so that the asphalt cold patch material is completely submerged and the water level is higher than the surface of the asphalt cold patch material, and add a surfactant to the water to remove bubbles in the water;

[0092] A64: Use negative pressure and vibration to fully remove the air in each group of asphalt cold patch material, measure the mass of water in each group of negative pressure containers containing asphalt cold patch material, and record it as m2;

[0093] A65: Pour out the cold patch material in each group of negative pressure containers respectively, and measure the mass of water in the negative pressure container, recorded as m3;

[0094] A66: Substitute m1, m2 and m3 into the formula B = m1 / [m1-(m2-m3)] to obtain the theoretical maximum relative density B of each group of asphalt cold patch material. Take the average of the theoretical maximum relative density B of each group as the final theoretical maximum relative density B.

[0095] In this embodiment, the vacuum method of step A6 can be specifically carried out through sub-steps A61 to A66. After the asphalt cold patch material is fully dispersed, the m1, m2 and m3 parameters are measured under negative pressure, and the theoretical maximum relative density formula is substituted to obtain the theoretical maximum relative density B of each group. The average is taken as the final theoretical maximum relative density B to improve accuracy.

[0096] It should be noted that the specific implementation methods of each sub-step may be as follows (one of the embodiments):

[0097] A61: The preparation process of asphalt cold patch material is the same as step A4. Then use a small shovel to repeatedly stir the asphalt cold patch material, and use hands to disperse the cold patch material that is still clumped after stirring, so as to achieve the dispersion standard of coarse aggregate without crushing, fine aggregate dispersed to less than 6.4mm, and no cold patch material sticking to the iron plate and small shovel.

[0098] A62: Use the equal division method to divide the cold patch materials in the iron plate into at least two groups of parallel tests, and level and calibrate the balance to reduce human errors. Prepare the theoretical maximum relative density tester, wipe the negative pressure container clean, and place it on the balance to zero. Put one group of asphalt cold patch materials into the negative pressure container, place it on the balance to read the mass, record it as m1, and check that the balance reading should not be less than the minimum mass of the sample in the specification.

[0099] A63: Pour water at about 20℃±0.5℃ into the negative pressure container to completely immerse the mixture and keep the water level 1cm to 2cm above the surface of the mixture. Add a surfactant with a concentration of 0.01%, such as detergent, to the water to more conveniently remove bubbles in the water.

[0100] A64: Tighten the exhaust valve of the theoretical maximum relative density tester, install and fix the negative pressure container, start the vacuum pump, make the negative pressure in the negative pressure container reach 3.7kPa±0.3kPa within 2 minutes, turn on the vibration switch, and start the stopwatch to time, and keep the negative pressure container vibrating strongly for 15min±2min to fully remove the air in the cold patch material. After the specified time, turn off the vibration switch and the vacuum pump, and let the container stand for 2min to allow the suspended particles to settle. Loosen the exhaust valve at a pressure relief speed of no more than 8kPa / s. Take out the negative pressure container, open the container cover, return the balance to zero, connect the balance and the mesh basket in the water tank, and slowly place the negative pressure container containing the asphalt cold patch material on the mesh basket in the water tank; after 10 minutes, weigh the mass of the negative pressure container and the asphalt cold patch material in water and record it as m2.

[0101] A65: Pour out the asphalt cold patch material in the negative pressure container, wipe the negative pressure container clean, immerse it completely in a constant temperature water tank at 25℃±5℃ and keep it warm for 10min±1min, then weigh the mass in the water of the negative pressure container and record it as m3. A66: Substitute m1, m2 and m3 into the formula B=m1 / [m1-(m2-m3)] to obtain the theoretical maximum relative density B of each group of asphalt cold patch material, and take the average of the theoretical maximum relative density B of each group as the final theoretical maximum relative density B.

[0102] Other structures and operations of the compaction test method of asphalt cold patch material according to the embodiment of the present invention are known to ordinary technicians in the field and will not be described in detail here.

[0103] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0104] Although the 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 claims and their equivalents.

Claims

1. A method for testing the compactability of asphalt cold patch material, characterized in that: The following steps are involved: A1: According to the compaction degree of the asphalt pavement to be tested, set the parameters of the rotary compactor, and start the rotary compactor multiple times to measure the internal rotation angle. When the angle error in multiple measurements is less than 0.02°, take the average of the multiple measured angles and set it as the rotation angle parameter of the rotary compactor. A2: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the rotary compactor, and use the rotary compactor to compact the asphalt specimens, and measure the mass of the asphalt specimens, which is recorded as m4; A3: Drill a notch from the top center of the asphalt specimen; A4: Fill the gap of the asphalt test piece with the asphalt cold patch material to obtain an asphalt cold patch test piece; A5: Use a rotary compactor to compact the asphalt cold patch specimen and measure the mass of the asphalt cold patch specimen, recorded as m5; A6: Prepare asphalt cold patch material according to at least two sets of parallel tests to calculate the theoretical maximum relative density B of asphalt cold patch material; A7: Use the difference between m5 and m4 to calculate the actual density A of the compacted cold patch material in the asphalt cold patch specimen; A8: The compaction degree G is obtained by using the ratio of the actual density A and the theoretical maximum relative density B, G = A / B.

2. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: In step A3, the volume of the notch is less than or equal to half of the total volume of the asphalt test piece.

3. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: In the step A3, the shape of the notch is the same as the shape of the asphalt test piece.

4. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: In the step A2, a cylindrical test mold is used as the test mold; in the step A3, a cylindrical drill bit is used for drilling the notch corresponding to the shape of the cylindrical test mold.

5. The method for testing the compactability of asphalt cold patch material according to claim 4, characterized in that: In step A7, substitute m5 and m4 into the formula Where h is the depth of the notch and d is the diameter of the notch; the actual density A of the compacted cold patch material is obtained.

6. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: The step A2 comprises the following steps: A21: Prepare asphalt specimens by enclosing the space between the test mold and the pressure plate of the gyratory compactor, and compact the asphalt specimens using the gyratory compactor; A22: Repeatedly humidify, dry and roll the top surface of the asphalt specimen within a preset time, and then measure the mass of the asphalt specimen, recorded as m4.

7. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: The step A1 further comprises: when the internal rotation angle includes a top internal rotation angle and a bottom internal rotation angle, starting the rotary compactor multiple times to measure the top internal rotation angle and the bottom internal rotation angle respectively; The average of the top inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the top inner rotation angle parameter of the gyratory compactor; The average of the bottom inner rotation angles with an error of less than 0.02° in multiple measurements is taken as the bottom inner rotation angle parameter of the gyratory compactor.

8. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: In step A6, the theoretical maximum relative density B of the asphalt cold patch material is calculated using a vacuum method.

9. The method for testing the compactability of asphalt cold patch material according to claim 1, characterized in that: The step A6 comprises the following sub-steps: A61: After the prepared asphalt cold patch material is cured at room temperature, the asphalt cold patch material is repeatedly turned over and mixed to ensure that the coarse aggregate is not crushed, the fine aggregate is dispersed to less than 6.4mm, and the asphalt cold patch material does not adhere; A62: Group the asphalt cold patch materials equally into at least two parallel test groups, place each group of asphalt cold patch materials into a negative pressure container, and measure the mass of each group of negative pressure containers containing asphalt cold patch materials, recorded as m1; A63: Pour water into the negative pressure container so that the asphalt cold patch material is completely submerged and the water level is higher than the surface of the asphalt cold patch material, and add a surfactant to the water to remove bubbles in the water; A64: Use negative pressure and vibration to fully remove the air in each group of asphalt cold patch material, measure the mass of water in each group of negative pressure containers containing asphalt cold patch material, and record it as m2; A65: Pour out the cold patch material in each group of negative pressure containers respectively, and measure the mass of water in the negative pressure container, recorded as m3; A66: Substitute m1, m2 and m3 into the formula B = m1 / [m1-(m2-m3)] to obtain the theoretical maximum relative density B of each group of asphalt cold patch material. Take the average of the theoretical maximum relative density B of each group as the final theoretical maximum relative density B.

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