CN110031336A - A kind of improved dynamic shear rheometer parallel-plate and its test method - Google Patents

Abstract

The invention discloses a kind of improved dynamic shear rheometer parallel-plate and its test methods.The improved dynamic shear rheometer parallel-plate includes upper parallel-plate and lower parallel-plate, and the upper parallel-plate includes bottom platform and first handle, and lower parallel-plate includes second handle, top platform, boss and sleeve；Top platform lower surface is fixedly connected with second handle, and top platform upper surface is fixedly connected with boss；The edge of top platform upper surface is detachably connected upright sleeve；The corresponding setting bottom platform in the top of boss, the upper surface of bottom platform is fixedly connected with first handle；Sample to be tested is placed between boss and bottom platform；First handle and second handle, which are installed with dynamic shear rheometer, to be connected.The present invention can be under the conditions of quantitative test has water, and the rheological property of pitch or rubber cement in true mineral aggregate surface contact conditions to complete the quantitative assessment to the anti-water damage ability of different type pitch or rubber cement based on pitch shear rheology instrument.

Description

An improved dynamic shear rheometer parallel plate and its testing method

technical field

The invention belongs to asphalt performance testing equipment, and relates to an improved parallel plate of a dynamic shear rheometer and a testing method thereof.

Background technique

Water damage to asphalt pavement is one of the main forms of asphalt pavement damage. According to existing research, water damage to asphalt pavement is one of the key factors that cause early pavement diseases. It is precisely because water damage is closely related to road performance. , which has increasingly become a worldwide problem in recent years. At present, the damage forms of water damage are mainly attributed to three types: cohesion damage, adhesion damage and cohesion-adhesion composite damage. Adhesion failure refers to the adhesion failure at the weak interface between asphalt and aggregate, and cohesion failure refers to cracking failure due to the decrease of cohesion in the asphalt or asphalt mortar. In response to the problem of water damage, different scholars have carried out in-depth research based on different theoretical methods (fracture mechanics, damage mechanics, etc.) and different scales (macro, micro and even nano), and many achievements have been formed at home and abroad. The evaluation and characterization of adhesion and asphalt peeling resistance are also included in the corresponding specifications. However, in the existing specifications, the evaluation of the water damage resistance of asphalt or asphalt mortar is mainly based on qualitative evaluation. For the problem that the correlation between the indicators and the actual application of the project is not strong, the quantitative evaluation methods are mostly complicated and the operation requirements are high. Therefore, it is of great significance and value to explore a new evaluation method for the water damage resistance of asphalt or asphalt mortar.

Although the mass percentage of asphalt in the asphalt mixture is only about 3% to 6%, as a typical thermorheological material, the rheological properties of asphalt will have a significant impact on the high and low temperature performance and fatigue performance of the asphalt mixture. , which has formed a consensus in the road industry. The process in which the traffic load on the road acts on the road surface is manifested as a cyclic process of road compression, then tension, and then compression. Therefore, the dynamic loading mode is used to develop the deformation characteristics of asphalt and its mixture under dynamic loads. Research and analysis of its dynamic mechanical response behavior will have important practical significance. In this context, domestic and foreign scholars have used dynamic shear rheometer (DSR) as an analytical instrument for the dynamic rheological properties of asphalt and its mixtures to study the dynamic mechanical properties of asphalt and its mixtures. Based on DSR, rheological data of asphalt over a wide temperature and frequency range can be obtained, enabling a more comprehensive analysis of the rheological properties of asphalt than traditional asphalt indicators.

However, the current mainstream shear rheometers are all defaulted to measure the rheological properties of asphalt in a normal state. The specific implementation is as follows: place the poured asphalt sample between the upper and lower fixtures, and then heat up to soften the asphalt. , and then control the distance between the upper and lower clamps to an appropriate position to form a "sandwich" structure to complete the test of the rheological properties of the intermediate asphalt layer. Obviously, based on DSR equipment, exploring the rheological properties of asphalt or asphalt mortar under unconventional test conditions (water or even salt water environment and real mineral surface contact state), on the one hand, will be able to further tap the application potential of DSR equipment, On the other hand, it also provides a new quantitative analysis and evaluation method and approach for exploring the failure mechanism of asphalt and mortar adhesion failure and cohesion failure.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an improved dynamic shear rheometer parallel plate and its test method, so that the dynamic rheological properties of asphalt and asphalt mortar in the real contact state of mineral materials under water conditions can be simulated, It provides a new analysis and evaluation method for characterizing the water damage resistance of asphalt and its mortar.

In order to achieve the above objects, the technical solutions of the present invention are as follows.

An improved dynamic shear rheometer parallel plate, comprising an upper parallel plate and a lower parallel plate, the upper parallel plate includes a bottom platform and a first handle, and the lower parallel plate includes a second handle, a top platform, a boss and a sleeve The lower surface of the top platform is fixedly connected to the second handle, and the upper surface of the top platform is fixedly connected to the boss; the surrounding edges of the upper surface of the top platform are detachably connected to an upright sleeve to form a groove that can hold liquid and form a sealing structure, The sleeve forms the side of the groove, and the top platform forms the bottom surface of the groove; the top of the boss is correspondingly provided with the bottom platform of the upper parallel plate, and the upper surface of the bottom platform is fixedly connected to the first handle; the top platform, the second handle, the boss , the bottom platform and the first handle are arranged concentrically; the sample to be tested is placed between the boss and the bottom platform; the first handle and the second handle are both installed and connected with the dynamic shear rheometer.

Preferably, the bottom platform, the top platform, the boss and the sleeve are all circular, and the bottom platform and the boss have the same diameter, and the diameter is 5-40 mm.

Preferably, the diameter of the bottom platform is 25mm or 8mm.

Preferably, the peripheral edges of the upper surface of the top platform are connected with the sleeve through a tenon-and-mortise structure.

Preferably, the first handle and the second handle are dumbbell structures whose middle diameter is smaller than the diameter of both ends, so as to be fixed on the dynamic shear rheometer; Instrument installation connection.

Preferably, the upper parallel plate and the lower parallel plate are made of metal material, the metal material has stable physical and chemical properties at a temperature of -20°C to 500°C, has a certain hardness, and does not undergo physical and chemical reaction with the salt solution.

Preferably, the thicknesses of the bottom platform, the top platform and the boss are all 1 mm to 10 mm.

Preferably, the boss, the top platform and the second handle are integrally formed; the bottom platform and the first handle are integrally formed.

The present invention also provides a method for testing the rheological properties of asphalt or asphalt mortar using the improved dynamic shear rheometer parallel plate, comprising the following steps:

1) Select the upper and lower parallel plates of the corresponding specifications according to the test purpose and requirements, assemble the sleeve on the top platform, and fix the second handle on the base of the dynamic shear rheometer and above the heating system by means of screws. Fix the first handle to the sleeve rod of the dynamic shear rheometer through screw clamping;

2) Complete the selection of parallel plate specifications, the calibration of the system, and the zeroing of the gap between the upper parallel plate and the lower parallel plate;

3) According to the test purpose, or in accordance with the "Highway Engineering Asphalt and Asphalt Mixture Test Regulations" JTG E20-2011, the People's Republic of China Petrochemical Industry Standard SH/T0777-2005, the American Road Traffic Official Association Standard AASHTOT315-09 Regulations and controls Mode, test target temperature, frequency, test time;

4) Put the pre-cast asphalt or asphalt mortar sample on the upper surface of the boss, and use the heating device of the dynamic shear rheometer to heat the upper parallel plate and the lower parallel plate, so that the upper parallel plate and the lower parallel plate are heated up to Temperature T, T≥46℃, after the asphalt or asphalt mortar sample is heated and softened, adjust the distance between the upper parallel plate and the lower parallel plate, remove the overflowing asphalt squeezed by the upper parallel plate and the lower parallel plate, and then pass the cooling system or heating The system cools or heats the asphalt or asphalt mortar sample to the test target temperature, and keeps the sample at the test target temperature for 15min-60min;

5) Add water or salt solution already at the test target temperature into the groove, and the height of the added water or salt solution in the groove is between the upper surface of the asphalt or asphalt mortar sample and the upper surface of the bottom platform , and then according to the purpose of the test, keep it at the target temperature of the test for a certain period of time;

6) Conduct dynamic rheological tests.

Preferably, the pre-prepared cylindrical mineral material is respectively fixed on the lower surface of the bottom platform and the upper surface of the boss, and the cylindrical mineral material includes the upper target mineral material fixed on the lower surface of the bottom platform and the lower part fixed on the upper surface of the boss The target mineral material; the cylindrical mineral material, the bottom platform and the boss are arranged concentrically, and the pre-cast asphalt or asphalt mortar sample is placed on the upper surface of the lower target mineral material.

Preferably, the cylindrical mineral material is bonded and fixed with the lower surface of the bottom platform and the upper surface of the boss by glue.

Preferably, the height of the added water or salt solution in the groove is the upper surface of the upper target mineral material.

Preferably, the machine model of the dynamic shear rheometer is AR-2000 rheometer produced by TA Company.

Preferably, the test target temperature for adjusting the dynamic shear rheometer is 5°C to 85°C.

Preferably, the test target temperature for adjusting the dynamic shear rheometer is -20-150°C.

Preferably, the frequency of adjusting the dynamic shear rheometer is 7.5E-7～628rad/s.

Compared with the prior art, the present invention has the following beneficial effects and advantages:

The improved parallel plate of the dynamic shear rheometer of the invention can bond the mineral material on both the upper parallel plate and the lower parallel plate, and can test the asphalt or asphalt glue on the surface of the real mineral material under anhydrous conditions without external sleeve. Rheological properties of pulp. After the sleeve is externally connected, the dynamic rheological properties of the asphalt or asphalt mortar samples can be tested when water (or salt solution) diffuses in the asphalt or mortar. In contrast, asphalt or asphalt mortar samples can be analyzed for performance degradation due to water damage (cohesion damage and adhesion damage). Therefore, the improved dynamic shear rheometer parallel plate provided by the present invention provides a way to quantitatively analyze the water damage resistance of asphalt or asphalt mortar samples, and has certain application value.

Description of drawings

Fig. 1 is the schematic diagram of the upper parallel plate provided by the present invention;

Fig. 2 is the schematic diagram of the lower parallel plate provided by the present invention;

Fig. 3 is the parallel plate schematic diagram under simulated mineral asphalt contact and water environment provided by the present invention;

Figure 4 is a dynamic shear rheometer (DSR) standard test fixture and rotation direction;

FIG. 5 is a schematic diagram of shear stress (strain) and phase difference.

The numbers in the figure represent: 1. Bottom platform, 201, First handle, 202, Second handle, 3. Top platform, 4, Boss, 5, Sleeve, 6, Upper target mineral material, 7, Lower target Mineral material, 8. Sample to be tested, 9. Water or salt solution, 10. Upper metal plate, 11. Lower metal plate.

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Detailed ways

As shown in FIG. 1, FIG. 2 and FIG. 3, the present embodiment provides an improved dynamic shear rheometer parallel plate, including an upper parallel plate and a lower parallel plate, and the upper parallel plate includes a bottom platform 1 and a first parallel plate A handle 201, the lower parallel plate includes a second handle 202, a top platform 3, a boss 4 and a sleeve 5; the lower surface of the top platform 3 is fixedly connected to the second handle 202, and the upper surface of the top platform 3 is fixedly connected to the boss 4; 3. The peripheral edge of the upper surface is detachably connected to the upright sleeve 5 to form a groove that can hold liquid. The sleeve 5 forms the side of the groove, and the top platform 3 forms the bottom surface of the groove; the top of the boss 4 corresponds to The bottom platform 1 of the upper parallel plate is set, and the upper surface of the bottom platform 1 is fixedly connected to the first handle 201; the top platform 3, the second handle 202, the boss 4, the bottom platform 1 and the first handle 201 are arranged concentrically; the asphalt sample 8 is placed between the boss 4 and the bottom platform 1; the first handle 201 and the second handle 202 are both installed and connected to the dynamic shear rheometer. The bottom platform 1, the top platform 3, the boss 4 and the sleeve 5 are all circular, the bottom platform 1 and the boss 4 have the same diameter, and the diameter is 25mm, and the peripheral edge of the upper surface of the top platform 3 passes through the tenon with the sleeve 5. The mortise structure is connected, the peripheral edge of the upper surface of the top platform 3 has a tenon structure, and the bottom of the sleeve 5 has a mortise structure. The first handle 201 and the second handle 202 are dumbbell structures with a middle diameter smaller than the diameters of both ends, so as to be installed on the dynamic shear rheometer and fixed by screw clamping. The boss 4, the top platform 3 and the second handle 202 are integrally formed; the bottom platform 1 and the first handle 201 are integrally formed.

The present embodiment also provides a method for testing the rheological properties of asphalt using the improved dynamic shear rheometer parallel plate, comprising the following steps:

1) Carry out the asphalt time scanning test with the test target temperature of 40°C, and select the bottom platform 1 and the boss 4 with a diameter of 25mm. The sleeve 5 is assembled on the top platform 3, the second handle 202 is fixed on the base of the dynamic shear rheometer and the heating system by screws, and the first handle 201 is fixed on the dynamic shear rheometer by screws. The sleeve rod of the instrument; the pre-prepared cylindrical mineral material is fixed on the lower surface of the bottom platform 1 and the upper surface of the boss 4 respectively by high-strength glue, and the cylindrical mineral material includes the upper target mineral material fixed on the lower surface of the bottom platform 1 6 and the lower target mineral material 7 fixed on the upper surface of the boss 4; the cylindrical mineral material, the bottom platform 1 and the boss 4 are coaxially arranged; the bottom platform 1 and the boss 4 have the same diameter, and the diameter is 25mm.

2) After the DSR control software completes the selection of the specifications of the parallel plates, the system calibration, and the clearance between the upper parallel plate and the lower parallel plate after bonding the target ore material to zero;

3) The model of the DSR machine used in this example is the AR-2000 rheometer produced by TA Company. According to the purpose of the test and research, the distance between the upper target mineral material and the lower target mineral material is adjusted to 1mm, and the adjustment test mode is time scan, and the frequency is set It is 10HZ, the stress control mode, the stress is set to 30kpa, the test duration is 2h, and the sampling time interval is 10s.

4) Put the pre-cast asphalt sample 8 on the upper surface of the lower target mineral material 7, use the heating device of the dynamic shear rheometer to heat the upper parallel plate and the lower parallel plate to 60°C, and the parallel plate heats up to drive the cylindrical mineral. After the asphalt sample 8 is softened, adjust the distance between the upper target mineral material 6 and the lower target mineral material 7, remove the overflowing asphalt squeezed by the upper target mineral material 6 and the lower target mineral material 7, and pass the Natural cooling cools the asphalt sample 8 to 40°C, and keeps it at the target temperature of 40°C for 15 minutes;

5) Add water already at 40°C into the groove, the height of the added water in the groove is the upper surface of the upper target mineral material 6, keep the temperature at 40°C for 1 hour, during which time the water will be in the asphalt osmotic diffusion;

6) Carry out the time scanning test, and finally obtain the test data such as complex modulus, loss modulus, storage modulus, phase angle, etc., and draw the y-x curve of complex modulus-loading times or time. In addition, only change the water condition to Anhydrous conditions, other parameters remain unchanged in the comparison test, by comparing the two sets of experimental results, the rheological property attenuation of asphalt in water environment can be obtained, so as to realize the quantitative analysis of fatigue damage under asphalt water damage.

The principle of DSR test is shown in Figure 4 and Figure 5. DSR can apply sinusoidal alternating shear stress to test the viscoelastic behavior of materials. The phase angle δ is the hysteresis angle between material strain and stress, and the phase angle of ideal elastic material and ideal viscous material are 0° and 90°, respectively, and the phase angle of the viscoelastic material is between 0° and 90°. By heating the sample and adjusting the distance between the metal plates, the sample to be tested forms a sandwich structure with the upper metal plate 10 and the lower metal plate 11. The instrument provides torque to drive the upper metal plate 10 to rotate, and the lower metal plate is fixed on the base of the instrument. The rheological properties of asphalt samples were tested by applying dynamic shear loads.

The processing methods of the upper target mineral material 6 and the lower target mineral material 7 are as follows: select parallel plates of corresponding specifications according to the test requirements, and determine the cylinder diameter of the block stone according to the specifications of the parallel plate, drill the core of the block stone, and use a cutting machine to cut the core. It is recommended that the thickness of the rock be selected as an integer in the range of 3 to 6 mm. In addition, in order to make the surface roughness of the tested ore as similar to the unprocessed ore as much as possible, laser testing equipment or other fine and micro texture testing equipment can be used to detect the roughness. number of sandpapers. The above methods are used to ensure the rationality and accuracy of the DSR test.

The duration of the soaking process of the sample to be tested in the presence of water can be selected according to the purpose of the test.

An improved parallel plate of dynamic shear rheometer provided by the present invention can test the dynamic rheological properties of asphalt or asphalt mortar samples when water (or salt solution) diffuses in asphalt or mortar. The comparison of the dynamic rheological data of the samples in the water state allows the analysis of the performance degradation of the asphalt or asphalt mortar samples due to water damage (cohesion damage and adhesion damage). Therefore, the improved dynamic shear rheometer parallel plate provided by the present invention provides a way to quantitatively analyze the water damage resistance of asphalt or asphalt mortar samples, and has certain application value.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the specific embodiments of the present invention can still be Modifications or equivalent replacement of some technical features without departing from the spirit of the technical solutions of the present invention shall all be included in the scope of the technical solutions claimed in the present invention.

Claims (10)

1. An improved dynamic shear rheometer parallel plate, characterized in that it comprises an upper parallel plate and a lower parallel plate, the upper parallel plate comprises a bottom platform (1) and a first handle (201), and the lower parallel plate It includes a second handle (202), a top platform (3), a boss (4) and a sleeve (5); the lower surface of the top platform (3) is fixedly connected to the second handle (202), and the upper surface of the top platform (3) is fixed The connecting boss (4); the peripheral edge of the upper surface of the top platform (3) is detachably connected to an upright sleeve (5) to form a groove that can hold liquid, the sleeve (5) constitutes the side of the groove, and the top The platform (3) constitutes the bottom surface of the groove; the top of the boss (4) is correspondingly provided with a bottom platform (1) of the upper parallel plate, and the upper surface of the bottom platform (1) is fixedly connected to the first handle (201); the top platform ( 3) The second handle (202), the boss (4), the bottom platform (1) and the first handle (201) are arranged concentrically; the sample to be tested is placed between the boss (4) and the bottom platform (1). The first handle (201) and the second handle (202) are both installed and connected with the dynamic shear rheometer. 2. The improved dynamic shear rheometer parallel plate according to claim 1, wherein the bottom platform (1), the top platform (3), the boss (4) and the sleeve (5) are all circular The diameter of the bottom platform (1) and the boss (4) are the same, and the diameter is 5~40mm. 3. The improved dynamic shear rheometer parallel plate according to claim 2, characterized in that the diameter of the bottom platform (1) is 25mm or 8mm. 4. The improved dynamic shear rheometer parallel plate according to claim 1, characterized in that, the peripheral edge of the upper surface of the top platform (3) is connected with the sleeve (5) through a tenon-and-mortise structure, and the top platform (3) A tenon structure is provided on the peripheral edges of the upper surface, and the tenon structure is matched with the mortise structure at the bottom of the sleeve (5). 5. The improved parallel plate of dynamic shear rheometer according to claim 1, characterized in that, the first handle (201) and the second handle (202) are dumbbell structures whose middle diameter is smaller than the diameter of both ends, so as to facilitate installation On the dynamic shear rheometer; the first handle (201) and the second handle (202) are installed and connected to the dynamic shear rheometer by means of screw clamping positions. 6. The improved dynamic shear rheometer parallel plate according to claim 1, wherein the upper parallel plate and the lower parallel plate are made of metal material, and the metal material is at a temperature of -20 ℃ ~ 500 ℃ No physical and chemical reaction with the salt solution; the thickness of the bottom platform (1), the top platform (3), and the boss (4) are all 1~10mm; the boss (4), the top platform (3) and the second handle ( 202) is integrally formed; the bottom platform (1) and the first handle (201) are integrally formed. 7. utilize the improved dynamic shear rheometer parallel plate described in any one of claim 1 to 6 to carry out the method for asphalt or asphalt mortar rheological property test, is characterized in that, comprises the steps: 1) Select the upper and lower parallel plates of corresponding specifications according to the test purpose and requirements, assemble the sleeve (5) on the top platform (3), and fix the second handle (202) to the dynamic shear flow through the screw clamp. Above the base of the rheometer and the heating system, the first handle (201) is fixed to the sleeve rod of the dynamic shear rheometer through screw clamping; 2) Complete the selection of the specifications of the parallel plate, the calibration of the system, and the zeroing of the gap between the upper parallel plate and the lower parallel plate; 3) According to the test purpose, or in accordance with the "Highway Engineering Asphalt and Asphalt Mixture Test Regulations" JTG E20-2011, the People's Republic of China Petrochemical Industry Standard SH/T0777-2005, the American Road Traffic Official Association Standard AASHTO T315-09 Regulations Control mode, test target temperature, frequency, test time; 4) Put a pre-cast asphalt or asphalt mortar sample on the upper surface of the boss (4), and use the heating device of the dynamic shear rheometer to heat the upper parallel plate and the lower parallel plate, so that the upper parallel plate and the lower parallel plate are parallel. The plate is heated to the temperature T, T≥46℃. After the asphalt or asphalt mortar sample is heated and softened, adjust the distance between the upper parallel plate and the lower parallel plate, remove the overflowing asphalt extruded from the upper parallel plate and the lower parallel plate, and then cool down The system or heating system cools or heats the asphalt or asphalt mortar sample to the test target temperature, and keeps the sample at the test target temperature for 15min~60min; 5) Add water or salt solution that is already at the test target temperature into the groove, and the height of the added water or salt solution in the groove is on the upper surface of the asphalt or asphalt mortar sample and on the bottom platform (1). Between the surfaces, according to the purpose of the test, keep it at the target temperature of the test for a period of time; 6) Conduct dynamic rheological tests. 8. The method for testing the rheological properties of asphalt or asphalt mortar using the improved dynamic shear rheometer parallel plate according to claim 7, characterized in that, on the lower surface of the bottom platform (1) and the boss ( The upper surfaces of 4) are respectively fixed with pre-prepared cylindrical mineral materials, and the cylindrical mineral materials include an upper target mineral material (6) fixed on the lower surface of the bottom platform (1) and a lower target fixed on the upper surface of the boss (4). Mineral material (7); cylindrical mineral material, bottom platform (1) and boss (4) are coaxially arranged, and a pre-cast asphalt or asphalt mortar sample is placed on the upper surface of the lower target mineral material (7) . 9. The method for testing the rheological properties of asphalt or asphalt mortar using an improved dynamic shear rheometer parallel plate according to claim 8, wherein the cylindrical mineral material and the lower surface of the bottom platform (1) And the upper surface of the boss (4) is fixed by glue. 10. the method that utilizes improved dynamic shear rheometer parallel plate to carry out asphalt or asphalt mortar rheological property test method according to claim 8, is characterized in that, the height of added water or salt solution in groove is The upper surface of the upper target material (6).