A rapid evaluation method for asphalt performance in the entire temperature range

Abstract

A method for quickly evaluating asphalt performance in the entire temperature range relates to the field of asphalt performance evaluation. The present invention is to solve the problems of low evaluation efficiency and large asphalt consumption in existing asphalt temperature performance evaluation methods. The present invention comprises: placing an asphalt sample on the parallel plates of a dynamic shear rheometer temperature control device; the asphalt sample has a diameter of 8 mm and a thickness of 0.5 mm; obtaining an asphalt high temperature performance evaluation index value based on the asphalt sample, and using the high temperature performance evaluation index value to evaluate the high temperature performance of the asphalt; obtaining an asphalt resistance to low temperature hardening performance index value based on the asphalt sample, and evaluating the asphalt resistance to low temperature hardening performance; obtaining an asphalt low temperature performance index value based on the asphalt sample, and evaluating the asphalt low temperature performance; obtaining an asphalt low temperature performance index value based on the asphalt sample, and evaluating the asphalt low temperature performance; obtaining an asphalt anti-fatigue performance index based on the asphalt sample, and evaluating the asphalt anti-fatigue performance. The present invention is used to evaluate asphalt performance.

Description

Technical Field

[0001] The invention relates to the field of asphalt performance evaluation, and in particular to a method for quickly evaluating asphalt performance in a full temperature range. Background Art

[0002] Asphalt and mixtures are the main materials for asphalt pavement, and their performance will have a great impact on the service quality of the pavement. Among them, asphalt, as a typical viscoelastic material, will produce different performance responses under different loading frequencies and temperatures. In order to reduce the occurrence of rutting and cracking diseases on asphalt pavements, suitable asphalt binders should be selected according to local climate characteristics. Therefore, it is very necessary to use reasonable testing methods to evaluate the high, medium and low temperature performance of asphalt.

[0003] At present, the commonly used asphalt performance evaluation methods include temperature scanning test based on dynamic shear rheometer (DSR), double-sided notch tension (DENT) test and delayed bending beam rheology (EBBR) test. Among them, the temperature scanning test based on DSR generally uses a 25mm rotor under the conditions of test temperature of 52℃~76℃ and temperature interval of 6℃, and conducts high temperature scanning test in parallel plates with a spacing of 1mm, or uses an 8mm rotor under the conditions of test temperature of 34℃~-2℃ and temperature interval of 6℃ / 12℃, and conducts medium and low temperature scanning in parallel plates with a spacing of 2mm. The complex shear modulus G* and phase angle δ of asphalt at different temperatures are collected to calculate the rutting factor (|G*| / sin(δ)), fatigue factor (| G*|·sin(δ)) etc. are used to evaluate the high temperature rutting resistance and fatigue cracking resistance of asphalt; the DENT test uses a force-ductility instrument to test the tensile length and load-displacement of asphalt at different temperatures, calculate its fracture energy and critical cracking displacement to evaluate the fatigue cracking resistance of asphalt; the EBBR test is an extension of the existing BBR test, using a bending beam rheometer to collect the creep rate m value and creep stiffness S of asphalt at different curing times, curing temperatures, and test temperatures, and calculate the temperature grade loss to evaluate the low temperature performance of asphalt. Obviously, the above-mentioned existing asphalt performance evaluation methods require many types of test instruments, long test time and large asphalt consumption, which leads to low efficiency in evaluating asphalt temperature performance and large asphalt consumption. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of low evaluation efficiency and large asphalt consumption in existing asphalt temperature performance evaluation methods, and to propose a method for rapid evaluation of asphalt performance in the full temperature range.

[0005] A method for rapid evaluation of asphalt performance in the full temperature range. The specific process is as follows:

[0006] Step 1: Place the asphalt sample on the parallel plates of the temperature control device of the dynamic shear rheometer;

[0007] Step 2: obtaining an asphalt high temperature performance evaluation index value based on the asphalt sample in step 1, and using the high temperature performance evaluation index value to evaluate the high temperature performance of the asphalt;

[0008] Step 3: Based on the asphalt sample in step 1, obtain the asphalt low temperature hardening resistance index value, and evaluate the asphalt low temperature hardening resistance performance, specifically:

[0009] The asphalt low temperature hardening resistance index value obtained based on the asphalt sample in step 1 is specifically:

[0010] First, the temperature of the dynamic shear rheometer temperature control device was set to 34°C and maintained;

[0011] Then, in the temperature range of 34 to -2°C, the control strain was set to 0.1% and the loading frequency was set to 0.1 to 10 rad / s to obtain the phase angle δ of the asphalt sample at different temperatures. D8-0.5 ;

[0012] Finally, obtain δ D8-0.5 The temperature equal to 30° is taken as the index value of asphalt anti-low temperature hardening performance T 30° ;

[0013] Step 4: obtaining the low temperature performance index value of asphalt based on the asphalt sample in step 1, and evaluating the low temperature performance of asphalt;

[0014] Step 5: Obtain the asphalt anti-fatigue performance index value based on the asphalt sample in step 1, and evaluate the asphalt anti-fatigue performance.

[0015] Furthermore, the asphalt sample has a diameter of 8 mm and a thickness of 0.5 mm.

[0016] Furthermore, in step 2, the asphalt high temperature performance evaluation index value is obtained based on the asphalt sample in step 1, and the high temperature performance evaluation index value is used to evaluate the high temperature performance of the asphalt, specifically:

[0017] Step 21: Based on the asphalt sample in step 1, set the strain control to 12% and the frequency to 10 rad / s in the temperature range of 52-76°C to obtain the rutting factor |G*| / sin(δ) at different temperatures. D8-0.5 , the temperature corresponding to the rutting factor of 1.0 kPa is taken as the classification temperature T D8-0.5 ;

[0018] Step 22: Set the classification temperature T obtained in step 21 to D8-0.5 Converted to asphalt high temperature performance evaluation index value T High ;

[0019] Step 2: Use high temperature performance evaluation index value T High Evaluate the high temperature performance of asphalt, specifically: T High The higher it is, the stronger the asphalt's high-temperature resistance to rutting is, that is, the better the asphalt's high-temperature performance is.

[0020] Furthermore, in step 22, the classification temperature T obtained in step 21 is D8-0.5 Converted to asphalt high temperature performance evaluation index value T High , specifically:

[0021] Lg(T High )=1.178×Lg(T D8-0.5 )-10.243.

[0022] Furthermore, the evaluation of the asphalt's resistance to low temperature hardening in step 3 is as follows: 30° The smaller it is, the better the asphalt's resistance to low-temperature hardening.

[0023] Furthermore, the asphalt low temperature performance index value is obtained based on the asphalt sample in step 1 in step 4, specifically:

[0024] First, the temperature of the dynamic shear rheometer temperature control device was set to 0°C, sheared for 240 seconds under a stress of 1.0 kPa, and then rested for 760 seconds. Then, the temperature of the dynamic shear rheometer temperature control device was adjusted to 5°C, and sheared for 240 seconds under a stress of 1.0 kPa, thereby obtaining the creep rate m at different temperatures.

[0025] Then, the temperature corresponding to when m is equal to 0.5 is obtained as the asphalt low temperature performance index value T (m＝0.5) .

[0026] Further, the creep rate m is obtained by:

[0027] LogS'(t)=A+B[Log(t)]+C[Log(t)]^ 2

[0028] |m|=B+2C[Log(t)]

[0029] Where t is time, A, B, C are regression coefficients, and S′(t) is the creep stiffness varying with time.

[0030] Furthermore, the low temperature performance of asphalt in step 4 is evaluated as follows: (m＝0.5) The smaller it is, the stronger the asphalt's resistance to low-temperature cracking is, that is, the better the asphalt's low-temperature performance is.

[0031] Furthermore, the asphalt anti-fatigue performance index value is obtained based on the asphalt sample in step 1 in step 5, specifically:

[0032] The temperature of the temperature control device of the dynamic shear rheometer was set to 15°C. After the temperature of the asphalt sample stabilized, the control stress was set to 8N for a tensile test until the asphalt reached a damaged state. The current failure length was collected as an index value of the asphalt's anti-fatigue performance.

[0033] Furthermore, the fatigue resistance of asphalt is evaluated in step five, specifically: the longer the current failure length is, the better the fatigue cracking resistance of asphalt is.

[0034] The beneficial effects of the present invention are:

[0035] The present invention provides a method for quickly evaluating the high, medium and low temperature performance of asphalt with only one instrument and a small amount of asphalt. The present invention designs the asphalt sample to be 8mm*0.5mm (diameter*thickness). The amount required for the asphalt performance evaluation of the present invention is less than 1g, while the existing asphalt evaluation method requires at least 300g of asphalt for the experiment. Therefore, the present invention reduces the amount of asphalt used to obtain the asphalt performance index. The present invention can use the same asphalt sample to evaluate the high, medium and low temperature performance of asphalt using a dynamic shear rheometer, shortening the evaluation cycle while reducing the complexity of asphalt performance evaluation, thereby improving the efficiency of asphalt performance evaluation, and the asphalt performance evaluation method proposed by the present invention has the advantages of strong operability and high repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flow chart of the present invention;

[0037] Figure 2 For D8 -0.5 mm specimen and D25 -1 Correlation of high temperature performance test results of mm specimens;

[0038] Figure 3 For D25 cal mm specimen and D25 -1 Correlation of composite shear modulus test results for mm specimens;

[0039] Figure 4 For D25 cal mm specimen and D25 -1 mm phase angle test result correlation;

[0040] Figure 5 For D25 cal mm specimen and D25 -1 Correlation of rutting factor test results in mm;

[0041] Figure 6 For D8 -0.5 mm specimen and D8 -2 mm sample frequency scanning test result correlation;

[0042] Figure 7 For D8 -0.5 mm specimen frequency sweep test and low temperature grade loss results correlation;

[0043] Figure 8 is the correlation between the shear creep test results and the BBR test and EBBR test results;

[0044] Fig. 9 Correlation between the tensile creep test and the DENT test results. DETAILED DESCRIPTION

[0045] Specific implementation method 1: Figure 1 As shown, the specific process of the method for rapid evaluation of asphalt performance in the full temperature range in this embodiment is as follows:

[0046] Step 1: Set the temperature control device of the dynamic shear rheometer to 64°C, place the asphalt sample on a parallel plate with a diameter of 8 mm, then adjust the distance between the parallel plates to 0.5 mm, and scrape off the excess asphalt sample;

[0047] Since the composite shear modulus and phase angle are greatly affected by the size, the setting of the parallel plate gap size often determines whether the properties and viscoelasticity of the asphalt itself are accurately reflected. First, when evaluating low temperature, the present invention uses an indicator T that is sensitive to dimensional changes. 30° , T (m＝0.5) Therefore, the present invention takes the low-temperature boundary size as the control index and sets the specimen diameter to 8mm; secondly, in order to meet the linear viscoelastic hypothesis and fatigue performance, the present invention controls the asphalt film thickness. If the asphalt film thickness is too small, due to the parallel plate gap size effect and the influence of the asphalt failure length, the test results often cannot better reflect the characteristics of the asphalt itself. Therefore, the present invention sets the specimen thickness to 0.5mm.

[0048] Step 2: Based on the asphalt sample in step 1, obtain the asphalt high temperature performance evaluation index value, and use the high temperature performance evaluation index value to evaluate the high temperature performance of asphalt:

[0049] Step 2: Using the asphalt sample from step 1, test the asphalt at a temperature of 52-76°C, with a strain control of 12% and a loading mode of 10 rad / s, and collect the complex shear modulus G* of the asphalt at different temperatures. D8-0.5 , phase angle δ D8-0.5 , rutting factor |G*| / sin(δ) D8-0.5And other indicators, and the temperature corresponding to the rutting factor of 1.0kPa is taken as the classification temperature T D8-0.5 ;

[0050] Step 22: obtain the classification temperature T in step 21 D8-0.5 Converted to asphalt high temperature performance evaluation index value T High , and use the high temperature performance evaluation index value to evaluate the high temperature performance of asphalt, specifically:

[0051] Step 221: The classification temperature T of the asphalt obtained in step 21 is D8-0.5 The equivalent grading temperature T of the traditional asphalt specimen (25 mm in diameter and 1 mm in thickness) is High :

[0052] Lg(T High )=1.178×Lg(T D8-0.5 )-10.243 (1)

[0053] The present invention converts the complex shear modulus G* at different temperatures into D8-0.5 , phase angle δ D8-0.5 , rutting factor |G*| / sin(δ) D8-0.5 Converted to conventional asphalt sample D25 -1 mm (diameter 25mm thickness 1mm) equivalent complex shear modulus G* at different temperatures cal , equivalent phase angle δ cal , equivalent rutting factor |G*| / sin(δ) cal , and using G* cal ,δ cal 、|G*| / sin(δ) cal Obtaining traditional asphalt sample D25 -1 mm (diameter 25mm thickness 1mm) equivalent grading temperature T High , from the validity of the formula (1) designed by the present invention, G* cal ,δ cal 、|G*| / sin(δ) cal Obtained by the following formula:

[0054] Equivalent composite shear modulus G* cal :

[0055] Lg(G* cal )=1.042×Lg(G* D8-0.5 )-0.202 (2)

[0056] Equivalent phase angle δ cal :

[0057] δ cal =0.846×δD8-0.5 +12.909 (3)

[0058] Equivalent rutting factor:

[0059] Lg[|G*| / sin(δ) cal ]=1.041×Lg[|G*| / sin(δ) D8-0.5 ]-0.201 (4)

[0060] Among them, T High Indicates the equivalent classification temperature of a sample with a diameter of 8 mm and a thickness of 0.5 mm, T D8-0.5 Indicates the classification temperature of a sample with a diameter of 8 mm and a thickness of 0.5 mm, G* cal It represents the equivalent composite shear modulus of a specimen with a diameter of 8 mm and a thickness of 0.5 mm, G* D8-0.5 It represents the composite shear modulus of a sample with a diameter of 8 mm and a thickness of 0.5 mm, δ cal It represents the equivalent phase angle of a sample with a diameter of 8 mm and a thickness of 0.5 mm, δ D8-0.5 It represents the phase angle of a sample with a diameter of 8 mm and a thickness of 0.5 mm, |G*| / sin(δ) cal It represents the equivalent rutting factor of a sample with a diameter of 8 mm and a thickness of 0.5 mm, |G*| / sin(δ) D8-0.5 It represents the rutting factor of a specimen with a diameter of 8 mm and a thickness of 0.5 mm;

[0061] Step 222: Set the equivalent classification temperature T High As an evaluation index for high temperature performance of asphalt, and to evaluate the high temperature performance of asphalt:

[0062] Among them, T High The higher it is, the stronger the asphalt's high-temperature resistance to rutting is, that is, the better the asphalt's high-temperature performance is.

[0063] D8 -0.5 mm sample (the asphalt sample designed by the present invention has a diameter of 8 mm and a thickness of 0.5 mm) and the traditional asphalt sample D25 -1 The correlation of high temperature performance test results of mm specimens is as follows Figure 2 As shown, D25 cal mm specimen and D25 -1 The correlation of the composite shear modulus test results of mm specimens is as follows Figure 3 As shown, D25 cal mm specimen and D25 -1 The correlation of the phase angle test results of mm is as follows Figure 4 As shown (R 2 represents the degree of fit index), D25 cal mm specimen and D25 -1The correlation of the rutting factor test results in mm is as follows Figure 5 In the present invention, the high temperature is greater than or equal to 30°C, the low temperature is less than 5°C, and the medium temperature is between 5°C and 30°C.

[0064] Step 3: Based on the asphalt sample in step 1, lower the temperature control device of the dynamic shear rheometer to 34°C and maintain the temperature for 10 minutes; under the temperature condition of 34 to -2°C, control the strain to 0.1%, the loading frequency to 0.1 to 10 rad / s, and collect the phase angle δ of the asphalt sample. D8-0.5 ; and the phase angle δ D8-0.5 The temperature corresponding to 30° (T 30° ) is used as an evaluation index for the asphalt's ability to resist low-temperature hardening. -0.5 mm specimen and D8 -2 mm sample frequency scanning test results correlation Figure 6 As shown, D8 -0.5 The correlation between the frequency sweep test of mm specimen and the low temperature grade loss results is as follows Figure 7 As shown;

[0065] Among them, T 30° The smaller it is, the better the asphalt's resistance to low-temperature hardening.

[0066] Step 4: Based on the asphalt sample in step 1, a shear creep test is performed on the asphalt sample to obtain the asphalt low temperature performance evaluation index value, specifically:

[0067] Step 4: 1. Adjust the temperature control device to 0°C, shear for 240s under a stress of 1.0kPa, and then rest for 760s; then adjust the temperature to 5°C, shear for 240s under a stress of 1.0kPa, and obtain the creep rate at different temperatures, such as Figure 8 As shown, specifically:

[0068] First, the creep stiffness is used to obtain the regression coefficients A, B, and C:

[0069] LogS'(t)=A+B[Log(t)]+C[Log(t)]^ 2

[0070] Then, the regression coefficients B and C are used to obtain the creep rate at different times:

[0071] |m|=B+2C[Log(t)]

[0072] Where t is time, A, B, C are regression coefficients, and S′(t) is the creep stiffness varying with time;

[0073] Step 42: Obtain the temperature when the creep rate is equal to 0.5 as the asphalt low temperature performance evaluation index value T (m＝0.5);

[0074] Among them, T (m＝0.5) The smaller it is, the stronger the asphalt's ability to resist cracking at low temperatures is, that is, the better the asphalt's low-temperature performance is;

[0075] Step 5: Based on the asphalt sample in step 1, adjust the temperature to 15°C until the temperature of the asphalt sample is stable, set the control stress to 8N, and conduct a tensile test until the asphalt reaches a failure state. Collect the failure length as an evaluation index of the asphalt fatigue resistance, and evaluate the asphalt fatigue resistance based on the evaluation index of the asphalt fatigue resistance. The correlation between the test results of the tensile creep test and the DENT test is as follows: Fig. 9 shown.

[0076] Among them, the longer the failure length, the better the asphalt's ability to resist fatigue cracking.

[0077] Step 6: Based on the evaluation index values ​​of steps 2 to 5, various asphalt samples are evaluated to select the asphalt pavement binder suitable for the current climate and environmental characteristics.

[0078] Example: To verify the beneficial effects of the present invention, the present invention evaluates the performance of 10 existing asphalts according to the method described in the specific implementation method:

[0079] This example obtains the T of each asphalt. High , T 30° , T (m＝0.5) , failure length / μm;

[0080] Among them, T High The higher the value, the better the high temperature performance of asphalt; T 30° The smaller the value, the better the asphalt's ability to resist low-temperature hardening. (m＝0.5) The smaller it is, the better the low-temperature performance of the asphalt is; the longer the failure length is, the better the fatigue cracking resistance of the asphalt is. Compared with other asphalts, asphalt J has the best high-temperature performance, and asphalt A has the best low-temperature performance and fatigue cracking resistance, as shown in Table 1.

[0081]

Claims

1. A method for rapid evaluation of asphalt performance in the full temperature range, characterized in that The specific process of the method is: Step 1: Place the asphalt sample on the parallel plates of the temperature control device of the dynamic shear rheometer; The asphalt sample has a diameter of 8 mm and a thickness of 0.5 mm; Step 2: Based on the asphalt sample in step 1, obtain the asphalt high temperature performance evaluation index value, and use the high temperature performance evaluation index value to evaluate the high temperature performance of asphalt, specifically: Step 21: Based on the asphalt sample in step 1, set the strain control to 12% and the frequency to 10 rad / s in the temperature range of 52-76°C to obtain the rutting factor |G*| / sin(δ) at different temperatures. D8-0.5 , the temperature corresponding to the rutting factor of 1.0 kPa is taken as the classification temperature T D8-0.5 ; Step 22: Set the classification temperature T obtained in step 21 to D8-0.5 Converted to asphalt high temperature performance evaluation index value T High , specifically: Lg(T High )=1.178×Lg(T D8-0.5 )-10.243 Step 2: Use high temperature performance evaluation index value T High Evaluate the high temperature performance of asphalt, specifically: T High The higher it is, the stronger the high-temperature rutting resistance of the asphalt is, that is, the better the high-temperature performance of the asphalt is; Step 3: Based on the asphalt sample in step 1, obtain the asphalt low temperature hardening resistance index value, and evaluate the asphalt low temperature hardening resistance value, specifically: The asphalt low temperature hardening resistance index value obtained based on the asphalt sample in step 1 is specifically: First, the temperature of the dynamic shear rheometer temperature control device was set to 34°C and maintained; Then, in the temperature range of 34 to -2°C, the control strain was set to 0.1% and the loading frequency was set to 0.1 to 10 rad / s to obtain the phase angle δ of the asphalt sample at different temperatures. D8-0.5 ; Finally, obtain δ D8-0.5 The temperature equal to 30° is taken as the index value of asphalt anti-low temperature hardening performance T 30° ; Step 4: obtaining the low temperature performance index value of asphalt based on the asphalt sample in step 1, and evaluating the low temperature performance of asphalt; Based on the asphalt sample in step 1, the low temperature performance index value of asphalt is obtained, specifically: First, the temperature of the dynamic shear rheometer temperature control device was set to 0°C, sheared for 240 seconds under a stress of 1.0 kPa, and then rested for 760 seconds. Then, the temperature of the dynamic shear rheometer temperature control device was adjusted to 5°C, and sheared for 240 seconds under a stress of 1.0 kPa, thereby obtaining the creep rate m at different temperatures. Then, the temperature corresponding to when m is equal to 0.5 is obtained as the asphalt low temperature performance index value T (m＝0.5) ; Step 5: obtaining the asphalt anti-fatigue performance index value based on the asphalt sample in step 1, and evaluating the asphalt anti-fatigue performance; Based on the asphalt sample in step 1, the asphalt fatigue resistance index value is obtained, specifically: The temperature of the temperature control device of the dynamic shear rheometer was set to 15°C. After the temperature of the asphalt sample stabilized, the control stress was set to 8N for a tensile test until the asphalt reached a damaged state. The current failure length was collected as an index value of the asphalt's anti-fatigue performance.

2. The method for rapid evaluation of asphalt performance in the full temperature range according to claim 1, characterized in that: The step 3 is to evaluate the asphalt's resistance to low temperature hardening, specifically: 30° The smaller it is, the better the asphalt's resistance to low-temperature hardening.

3. The method for rapid evaluation of asphalt performance in the full temperature range according to claim 2, characterized in that: The creep rate m is obtained as follows: LogS′(t)=A+B[Log(t)]+C[Log(t)]^ 2 |m|=B+2C[Log(t)] Where t is time, A, B, C are regression coefficients, and S′(t) is the creep stiffness varying with time.

4. The method for rapid evaluation of asphalt performance in the full temperature range according to claim 3 is characterized in that: The step 4 of evaluating the low temperature performance of asphalt is as follows: (m＝0.5) The smaller it is, the stronger the asphalt's resistance to low-temperature cracking is, that is, the better the asphalt's low-temperature performance is.

5. The method for rapid evaluation of asphalt performance in the full temperature range according to claim 4, characterized in that: The step five of evaluating the fatigue resistance of asphalt is as follows: the longer the current failure length is, the better the fatigue cracking resistance of the asphalt is.

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