A test method for high temperature performance difference of road asphalt mixture

Abstract

The present invention discloses a method for testing the high-temperature performance difference of road asphalt mixture, which belongs to the technical field of high-temperature performance testing of asphalt mixture, and specifically includes the following steps: step one, core sample selection; step two, core sample heating; step three, height adjustment; step four, performance testing; step five, compression test. The present invention simulates the use of the asphalt mixture under high temperature by heating the asphalt mixture, and combines the pressure generated by the pressure wheel to make a linear rolling motion on the surface of the asphalt mixture, which can simulate the rolling of the vehicle on the surface of the asphalt mixture on the road surface, so that the performance of the asphalt mixture at high temperature can be comprehensively tested based on the actual application of the asphalt mixture, and the free fall of the sphere is used to test the compression resistance and bearing capacity of the asphalt mixture. The testing method is simple, and the test data of the asphalt mixture is accurate.

Description

Technical Field

[0001] The embodiment of the present invention relates to the technical field of high temperature performance testing of asphalt mixtures, and in particular to a method for testing the high temperature performance differences of road asphalt mixtures. Background Art

[0002] Asphalt mixture is a composite material, mainly composed of asphalt, coarse aggregate, fine aggregate, mineral powder, and sometimes polymer and wood cellulose are added. These materials of different quality and quantity are mixed to form different structures and have different mechanical properties.

[0003] Asphalt mixture is usually laid on the road to improve the smoothness and compression resistance of the road. However, in recent years, with the increase in vehicles and the influence of high temperature on asphalt mixture, asphalt mixture is prone to softening, and the rolling of vehicles can easily affect the performance of asphalt mixture.

[0004] However, up to now, asphalt mixtures have been tested at high temperatures in a variety of ways, the most common of which are through Marshall testers and vehicle pull-off testers;

[0005] The Marshall tester mainly uses the upper and lower pressure heads to load the test samples to test the performance of asphalt mixtures. At present, a large number of studies have shown that the Marshall stability index of the Marshall test is not directly related to the road performance of asphalt aggregates, and its performance cannot be correctly evaluated. In addition, this method cannot correctly simulate the mechanical state of the actual road surface.

[0006] Although the wheel rutting tester can simulate the road surface, the stress distribution they simulate is uneven, and the mechanical parameters cannot be calculated by analytical calculation of the actual deformation. Therefore, the test indicator rutting depth cannot be used for road surface design and the establishment of rutting models. Moreover, the size of the rutting used in the experiment remains unchanged, which will eventually affect the test results of the asphalt mixture. In addition, the equipment is bulky and inconvenient to operate, and requires a matching wheel rutting tester and a wheel rolling tester. The equipment is relatively expensive, resulting in many construction sites and even some university laboratories not having the experimental conditions.

[0007] However, there is currently no simple and complete test method for the high-temperature performance test of asphalt mixtures. In view of the above situation, the present invention proposes a test method for the high-temperature performance difference of road asphalt mixtures, which can not only effectively simulate the bearing capacity and environmental conditions of pavement asphalt mixtures, but also obtain mechanical parameters and can be applied to the test method for the high-temperature performance difference of asphalt mixtures. Summary of the invention

[0008] To this end, an embodiment of the present invention provides a method for testing the high-temperature performance differences of road asphalt mixtures. The method heats the asphalt mixture to simulate the use of the asphalt mixture under high temperature conditions, and combines the pressure generated by a pressure wheel to perform linear rolling motion on the surface of the asphalt mixture to simulate the rolling of the vehicle on the surface of the road asphalt mixture. In addition, by changing the diameter and width of the pressure wheel, the performance of the asphalt mixture at high temperature can be comprehensively tested based on the actual application of the asphalt mixture. The bearing capacity and environmental conditions of the road asphalt mixture can be effectively simulated, and the mechanical parameters can be obtained and applied to the method for testing the high-temperature performance differences of the asphalt mixture.

[0009] In order to achieve the above object, the embodiment of the present invention provides the following technical solution: a method for testing the high temperature performance difference of road asphalt mixture, which specifically includes the following steps:

[0010] Step 1: Select 4-6 groups of rectangular core samples that have been laid flat and rolled from the asphalt pavement construction site, and test the gross volume and relative density of the core samples respectively;

[0011] Step 2: Adjust the temperature of the constant temperature water tank to 45-60°C, place the rectangular core sample in the constant temperature water tank for 30-45 minutes, and place the pressing wheel of the test equipment in the constant temperature water tank or heating box and heat it to the same temperature;

[0012] Step 3: After the pressure wheel of the test equipment is heated, it is placed above the rectangular core sample, and the height between the rectangular core sample and the pressure wheel is set;

[0013] Step 4:

[0014] S1. Use the hydraulic rod of the test equipment to drive the pressing wheel to move to the surface of the rectangular core sample, set the hydraulic pressure of the hydraulic rod of the test equipment, and use the electric guide rail of the test equipment to drive the pressing wheel to move horizontally on the surface of the rectangular core sample to check whether there is an indentation on the surface of the core sample;

[0015] S2. Adjust the pressure of the hydraulic rod of the test equipment. The pressure is different from that in S1. The specific range is between ≦1mpa≦3mpa. Continue to press horizontally on the surface of the same core sample to check whether there is an indentation on the surface of the core sample.

[0016] S3, select another set of core samples, and change the wheel size of the pressing wheel. The diameter of the pressing wheel is within the range of ≦Φ10cm≦Φ15cm and the width is ≦3cm≦5cm. At the same time, the pressing wheel is moved horizontally on the same core sample under the same pressure;

[0017] S4. Combined with the two different pressures in S1 and S2, the depth of the indentation on the surface of the core sample or the depth of the asphalt mixture is measured. At the same time, in S3, the indentation on the surface of the core sample after the same pressure and different replacement of the pressing wheel is measured, and the measured quantity is recorded as a set of data.

[0018] Step 5. Select several other groups of core samples and keep them warm at the same temperature as in step 2. Use free fall motion to drop a ball of the same temperature from a height, perform a hammer test on the asphalt mixture, check the depth of the surface of the asphalt mixture, and record another set of data.

[0019] Furthermore, in step 1, when the rectangular core sample is subjected to the gross volume test, the length, width and height of the rectangular core sample are measured, and the volume of the rectangular core sample is calculated. The density of the asphalt mixture of the rectangular core sample is 2.5 g / m 3 .

[0020] Furthermore, in step 2, a travel sensor is installed on the slide bar of the hydraulic rod and the electric guide rail, and a pressure sensor is installed on the surface of the pressure wheel.

[0021] Furthermore, in step three, when setting the height of the pressing wheel and the rectangular core sample, a support plate may be added to the bottom of the rectangular core sample to keep the surface of the asphalt mixture in contact with the bottom of the pressing wheel.

[0022] Furthermore, in step five, the specific operations are:

[0023] Several other core samples were heated in the same way, and the sphere was heated. The free fall of the sphere was performed by hanging the sphere with a hanging rope, moving the sphere to a certain height and releasing it, so that the sphere hit the surface of the asphalt concrete.

[0024] By changing the falling height, volume and weight of the sphere, the collapse of the surface of the asphalt mixture is observed, the performance of the asphalt concrete is tested, and multiple groups of test results are recorded.

[0025] Furthermore, the diameter of the sphere is controlled within the range of Φ5cm-Φ10cm, the weight is 10kg-20kg, and the height is 30-50cm.

[0026] The embodiments of the present invention have the following advantages:

[0027] By selecting asphalt mixture from the asphalt pavement construction site and heating the asphalt mixture, the use of asphalt pavement under high temperature conditions can be effectively simulated, and the pressure generated by vehicles on the asphalt pavement can be simulated by using hydraulic rods to drive the pressure wheels to apply pressure to the surface of the asphalt mixture. The electric guide rails can be used to drive the pressure wheels to move horizontally on the surface of the asphalt mixture to effectively simulate the scene of a car driving on an asphalt pavement. Therefore, based on the actual application of the asphalt mixture, the performance of the asphalt mixture under high temperature can be comprehensively tested. In the test process, by changing the pressure of the hydraulic rod, the diameter and width of the pressure wheel, it can be used for scenes where vehicles of different sizes are driving on asphalt pavement.

[0028] The compression resistance of asphalt mixture at high temperature is tested by free fall. A sphere is dropped from a height to perform a hammer test on the surface of the asphalt mixture, and it is observed whether the surface of the asphalt mixture collapses. By changing the height at which the sphere falls, the diameter of the sphere, and the weight of the sphere, the maximum bearing capacity and compression resistance of the asphalt mixture can be effectively tested. The performance of asphalt mixture at high temperature is comprehensively tested in different ways.

[0029] The pressure sensor and stroke sensor on the testing equipment can effectively test the maximum pressure generated by the asphalt mixture during the test and the distance the pressure wheel travels on the surface of the asphalt mixture, thereby effectively judging the maximum bearing capacity and load performance of the asphalt mixture in a high temperature environment and improving the accuracy of asphalt mixture testing.

[0030] In summary, compared with the conventional testing methods currently used, the testing method adopted by the present invention can not only effectively simulate the bearing capacity and environmental conditions of the pavement asphalt mixture, but also obtain mechanical parameters and can be applied to the testing of the high-temperature performance differences of the asphalt mixture, thereby improving the accuracy of the testing performance of the asphalt mixture at high temperatures. DETAILED DESCRIPTION

[0031] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are 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.

[0032] Embodiment 1: A method for testing the high temperature performance difference of road asphalt mixture, comprising the following steps:

[0033] Step 1: Select 6 groups of rectangular core samples that have been laid flat and rolled from the asphalt pavement construction site, and test the gross volume and relative density of the core samples respectively;

[0034] Step 2: Adjust the temperature of the constant temperature water tank to 60°C, place the rectangular core sample in the constant temperature water tank for 35 minutes, place the pressing wheel of the test equipment in the constant temperature water tank or heating box, heat it to the same temperature, install the travel sensor on the sliding rod of the hydraulic rod and the electric guide rail, and install the pressure sensor on the surface of the pressing wheel;

[0035] Step 3: After the pressure wheel of the test equipment is heated, it is placed above the rectangular core sample, and a support plate is added to the bottom of the rectangular core sample to keep the surface of the asphalt mixture in contact with the bottom of the pressure wheel to set the height between the rectangular core sample and the pressure wheel;

[0036] Step 4:

[0037] S1. Use the hydraulic rod of the test equipment to drive the pressing wheel to move to the surface of the rectangular core sample, set the hydraulic pressure of the hydraulic rod of the test equipment, and use the electric guide rail of the test equipment to drive the pressing wheel to move horizontally on the surface of the rectangular core sample to check whether there is an indentation on the surface of the core sample. The pressure of the hydraulic rod is 2 MPa, the diameter of the pressing wheel is Φ10 cm, and the width is 3 cm;

[0038] S2. Adjust the pressure of the hydraulic rod of the test equipment. The pressure is different from that in S1. Specifically, it is 3 MPa. Continue to press horizontally on the surface of the same core sample to check whether there is an indentation on the surface of the core sample.

[0039] S3, select another set of core samples, and change the wheel size of the pressing wheel, the diameter of the pressing wheel is Φ20cm, the width is 7cm, and at the same time, the pressing wheel is made to move horizontally on the same core sample under the same pressure;

[0040] S4. Combined with the two different pressures in S1 and S2, the depth of the indentation on the surface of the core sample or the depth of the asphalt mixture is measured. At the same time, in S3, the indentation on the surface of the core sample after the same pressure and different replacement of the pressing wheel is measured, and the measured quantity is recorded as a set of data.

[0041] Step 5: Select several other groups of core samples and keep them warm at the same temperature as in step 2. At the same time, use free fall motion to make a ball of the same temperature fall from a height, perform a hammer test on the asphalt mixture, and check the depth of the surface of the asphalt mixture to record another set of data;

[0042] Specifically, several other groups of core samples are heated in the same manner, and the sphere is heated, and the free fall motion of the sphere is performed by suspending the sphere by a hanging rope, moving the sphere to a certain height and then releasing it, so that the sphere hits the surface of the asphalt concrete;

[0043] By changing the falling height, volume and weight of the sphere, the collapse of the asphalt mixture surface is observed, the performance of the asphalt concrete is tested, and multiple groups of test results are recorded;

[0044] The diameter of the sphere is Φ8cm, the weight is 10kg and the height is 30cm.

[0045] In this embodiment, multiple groups of rectangular samples are collected from the asphalt construction site, and the samples are heated to 60°C in a constant temperature water tank to simulate the use of the asphalt mixture at high temperature outdoors. At the same time, the pressing wheel moves horizontally on the surface of the asphalt mixture to simulate the rolling of the road asphalt by the wheels of the car at high temperature, thereby testing the compression resistance of the asphalt mixture at high temperature, and by adjusting the downward pressure of the pressing wheel, it is used to simulate cars of different weights;

[0046] Secondly, this embodiment simulates the wheel rolling conditions of different vehicle bodies by changing the pressure wheels of different sizes, and conducts free fall hammering experiments on other groups of core samples. By changing the height, weight and volume of the sphere, the compression resistance of the asphalt mixture after softening at a specific high temperature is tested.

[0047] Embodiment 2: A method for testing the high temperature performance difference of road asphalt mixture, comprising the following steps:

[0048] Step 1: Select 6 groups of rectangular core samples that have been laid flat and rolled from the asphalt pavement construction site, and test the gross volume and relative density of the core samples respectively;

[0049] Step 2: Adjust the temperature of the constant temperature water tank to 60°C, place the rectangular core sample in the constant temperature water tank for 35 minutes, place the pressing wheel of the test equipment in the constant temperature water tank or heating box, heat it to the same temperature, install the travel sensor on the sliding rod of the hydraulic rod and the electric guide rail, and install the pressure sensor on the surface of the pressing wheel;

[0050] Step 3: After the pressure wheel of the test equipment is heated, it is placed above the rectangular core sample, and a support plate is added to the bottom of the rectangular core sample to keep the surface of the asphalt mixture in contact with the bottom of the pressure wheel, so as to set the height between the rectangular core sample and the pressure wheel;

[0051] Step 4:

[0052] S1. Use the hydraulic rod of the test equipment to drive the pressing wheel to move to the surface of the rectangular core sample, set the hydraulic pressure of the hydraulic rod of the test equipment, use the electric guide rail of the test equipment to drive the pressing wheel to move horizontally on the surface of the rectangular core sample, and check whether there is an indentation on the surface of the core sample. The pressure of the hydraulic rod is 4 MPa, the diameter of the pressing wheel is Φ20 cm, and the width is 4 cm;

[0053] S2. Adjust the pressure of the hydraulic rod of the test equipment. The pressure is different from that in S1. Specifically, it is 5 MPa. Continue to press horizontally on the surface of the same core sample to check whether there is an indentation on the surface of the core sample.

[0054] S3, select another set of core samples, and change the wheel size of the pressing wheel, the diameter of the pressing wheel is 20cm, the width is 10cm, and at the same time, the pressing wheel is made to move horizontally on the same core sample under the same pressure;

[0055] S4. Combined with the two different pressures in S1 and S2, the depth of the indentation on the surface of the core sample or the depth of the asphalt mixture is measured. At the same time, in S3, the indentation on the surface of the core sample after the same pressure and different replacement of the pressing wheel is measured, and the measured quantity is recorded as a set of data.

[0056] Step 5: Select several other groups of core samples and keep them warm at the same temperature as in step 2. At the same time, use free fall motion to make a ball of the same temperature fall from a height, perform a hammer test on the asphalt mixture, and check the depth of the surface of the asphalt mixture to record another set of data;

[0057] Specifically, several other groups of core samples are heated in the same manner, and the sphere is heated, and the free fall motion of the sphere is performed by suspending the sphere by a hanging rope, moving the sphere to a certain height and then releasing it, so that the sphere hits the surface of the asphalt concrete;

[0058] By changing the falling height, volume and weight of the sphere, the collapse of the asphalt mixture surface is observed, the performance of the asphalt concrete is tested, and multiple groups of test results are recorded;

[0059] The diameter of the sphere is Φ6cm, the weight is 15kg and the height is 35cm.

[0060] In this embodiment, the basic test method is the same as that in embodiment 1, except that this embodiment changes the pressure parameters of the hydraulic rod and changes the width and diameter of the pressure wheel, thereby simulating the rolling of the asphalt mixture by vehicles of different weights and wheels of different diameters and widths, and testing the optimal performance value of the asphalt mixture. The results show that under the same high temperature, the stability of the asphalt mixture is affected by the surface weight pressure, volume size and contact area;

[0061] At the same time, when conducting a free fall experiment on the asphalt mixture, the maximum compressive strength of the asphalt mixture is tested by changing the falling height, diameter and weight of the ball.

[0062] Comparative Example 1: A method for testing the high temperature performance difference of road asphalt mixture, comprising the following steps:

[0063] Step 1: Select 6 groups of circular core samples that have been laid and rolled from the asphalt pavement construction site, and test the gross volume and relative density of the core samples respectively;

[0064] Step 2: Adjust the temperature of the thermostatic water bath to 45-60°C, place the round core sample in the thermostatic water bath and keep it warm for 30-45 minutes, and place the upper and lower pressure heads of the Marshall tester in the thermostatic water bath or oven and heat them to the same temperature;

[0065] Step 3: Install the heated upper and lower pressure heads on the loading device respectively, place the heated round core sample on the surface of the lower pressure head, start the loading device, and make the upper and lower pressure heads perform load test on the core sample at a loading speed of 50±5mm / min;

[0066] Step 4: Calculate the stability of the asphalt mixture to detect the performance stability of the asphalt mixture at high temperature.

[0067] The comparative example is the most widely used test method for high-temperature performance testing of asphalt mixtures. The high-temperature stability of asphalt is measured using a Marshall tester after heating the core sample.

[0068] Summary: According to the above-mentioned Examples 1-2 and the comparative examples, when the asphalt mixture is tested at the same high temperature, the conventional Marshall test method can only test the stability of the asphalt mixture at high temperature, but the test accuracy is not as good as the test method in Examples 1 and 2 of the present invention. Examples 1 and 2 can fully simulate the road asphalt mixture under high temperature, and be rolled by rollers with different pressures, weights and volumes, thereby improving the accuracy of the asphalt mixture test standard, and can test the compressive performance of the asphalt mixture at high temperature. According to Examples 1 and 2, it can be concluded that when the asphalt mixture is under the same temperature environment, its surface is subjected to different pressures, weights and contact areas, which will affect the performance of the asphalt mixture.

[0069] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

[0070] The terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as within the scope of implementation of the present invention without substantially changing the technical content.

Claims

1. A method for testing the high temperature performance difference of road asphalt mixture, characterized by: The specific steps include: Step 1: Select 4-6 groups of rectangular core samples that have been laid flat and rolled from the asphalt pavement construction site, and test the gross volume and relative density of the core samples respectively; Step 2: Adjust the temperature of the constant temperature water tank to 45-60°C, place the rectangular core sample in the constant temperature water tank for 30-45 minutes, and place the pressing wheel of the test equipment in the constant temperature water tank or heating box and heat it to the same temperature; Step 3: After the pressure wheel of the test equipment is heated, it is placed above the rectangular core sample, and the height between the rectangular core sample and the pressure wheel is set; Step 4: S1. Use the hydraulic rod of the test equipment to drive the pressing wheel to move to the surface of the rectangular core sample, set the hydraulic pressure of the hydraulic rod of the test equipment, and use the electric guide rail of the test equipment to drive the pressing wheel to move horizontally on the surface of the rectangular core sample to check whether there is an indentation on the surface of the core sample. The pressure of the hydraulic rod is 2 MPa, the diameter of the pressing wheel is Φ10 cm, and the width is 3 cm; S2. Adjust the pressure of the hydraulic rod of the test equipment. The pressure is different from that in S1 and ranges from 1 MPa to 3 MPa. Continue to press horizontally on the surface of the same core sample to check whether there is an indentation on the surface of the core sample. S3, select another group of core samples, and change the wheel size of the pressing wheel. The diameter of the pressing wheel is different from that of the pressing wheel in S1 and S2. The diameter of the pressing wheel is Φ20 cm and the width is 7 cm. At the same time, the pressing wheel is made to move horizontally on the same core sample under the same pressure; S4, combining the two groups of different pressures in S1 and S2, measuring the depth of the indentation on the surface of the core sample or the depth of the asphalt mixture sinking into it, and at the same time in S3, measuring the indentation on the surface of the core sample after the same pressure and different replacement of the pressing wheel, and recording the measured quantity as a group of data; Step 5. Select several other groups of core samples and keep them warm at the same temperature as in step 2. Use free fall motion to drop a ball of the same temperature from a height, perform a hammer test on the asphalt mixture, check the depth of the surface of the asphalt mixture, and record another set of data.

2. A method for testing the high temperature performance difference of road asphalt mixture according to claim 1, characterized in that: In step 1, when testing the gross volume of the rectangular core sample, the length, width and height of the rectangular core sample are measured, and the volume of the rectangular core sample is calculated. The density of the asphalt mixture of the rectangular core sample is 2.5 g / m 3 .

3. A method for testing the high temperature performance difference of road asphalt mixture according to claim 1, characterized in that: In step 2, a travel sensor is installed on the slide bar of the hydraulic rod and the electric guide rail, and a pressure sensor is installed on the surface of the pressure wheel.

4. A method for testing the high temperature performance difference of road asphalt mixture according to claim 1, characterized in that: In step three, when setting the height of the pressing wheel and the rectangular core sample, a support plate may be added to the bottom of the rectangular core sample to keep the surface of the asphalt mixture in contact with the bottom of the pressing wheel.

5. A method for testing the high temperature performance difference of road asphalt mixture according to claim 1, characterized in that: In step 5, the specific operations are: Several other core samples were heated in the same way, and the sphere was heated. The free fall of the sphere was performed by hanging the sphere with a hanging rope, moving the sphere to a certain height and releasing it, so that the sphere hit the surface of the asphalt concrete. By changing the falling height, volume and weight of the sphere, the collapse of the asphalt mixture surface is checked, the performance of the asphalt concrete is tested, and multiple groups of test results are recorded.

6. A method for testing the high temperature performance difference of road asphalt mixture according to claim 5, characterized in that: The diameter of the sphere is controlled in the range of Φ5cm-Φ10cm, the weight is 10kg-20kg, and the height is 30-50cm.