1、Standard Method of Test for Determining Rutting Susceptibility of Hot Mix Asphalt (HMA) Using the Asphalt Pavement Analyzer (APA) AASHTO Designation: T 340-10 (2015) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-
2、2d T 340-1 AASHTO Standard Method of Test for Determining Rutting Susceptibility of Hot Mix Asphalt (HMA) Using the Asphalt Pavement Analyzer (APA) AASHTO Designation: T 340-10 (2015) 1. SCOPE 1.1. This method describes a procedure for testing the rutting susceptibility of hot mix asphalt (HMA) usin
3、g the Asphalt Pavement Analyzer (APA). 1.2. Annex A1 contains procedures for calibration checks for several APA components and related equipment. 1.3. Appendix X1 presents specifications for, and discussion concerning, several options for APA testing parameters often employed by APA users. 1.4. The
4、values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is t
5、he responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: T 166, Bulk Specific Gravity (Gmb) of Compacted Hot Mix Asphalt (HMA) Using Satur
6、ated Surface-Dry Specimens T 168, Sampling Bituminous Paving Mixtures T 209, Theoretical Maximum Specific Gravity (Gmm) and Density of Hot Mix Asphalt (HMA) T 269, Percent Air Voids in Compacted Dense and Open Asphalt Mixtures T 312, Preparing and Determining the Density of Asphalt Mixture Specimens
7、 by Means of the Superpave Gyratory Compactor 2.2. ASTM Standard: E1, Standard Specification for ASTM Liquid-in-Glass Thermometers 3. APPARATUS 3.1. APAA thermostatically controlled device designed to test the rutting susceptibility of HMA by applying repetitive linear loads to compacted test specim
8、ens through pressurized hoses via wheels. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d T 340-2 AASHTO 3.1.1. The APA shall be thermostatically controlled to maintain the test temperature and con
9、ditioning chamber at any set point between 4 and 72C (40 and 160F) within 1C (2F). 3.1.2. The APA shall be capable of independently applying loads up to 578 N (130 lbf) to the wheels. The loads shall be calibrated to the specified test load by an external-force transducer. 3.1.3. The APA shall be ca
10、pable of adjusting the pressure in the test hoses and maintaining up to 862 kPa (125 psi) in the test hoses. 3.1.4. The APA shall be capable of testing six cylindrical specimens. 3.1.5. The test molds shall be rectangular in shape, be composed of ultra-high molecular weight (UHMW) polyethylene, fit
11、snugly within the testing position in the APA testing chamber, and contain two holes in which to insert the specimens. The dimensions of each hole shall be 150 2.0 mm (5.91 0.08 in.) in diameter by 75.0 2.0 mm (2.95 0.08 in.) tall. 3.1.6. The APA shall have a programmable master cycle counter that c
12、an be preset to the desired number of cycles for a test. The APA shall be capable of automatically stopping the test at the completion of the programmed number of cycles. 3.1.7. The test hoses shall be composed of a nylon tube with high-tensile textile cord reinforcement and a synthetic rubber cover
13、. The nominal inside diameter of the hoses shall be 19.0 mm (0.75 in.); the nominal outside diameter of the hoses shall be 29.5 mm (1.16 in.). The maximum working pressure (WP) of the hoses shall be 5.17 MPa (750 psi). The hoses should be replaced when any of the outer rubber casing exhibits signifi
14、cant wear. Follow the APA manufacturers instructions for the technique on replacing hoses. Note 1A Gates 77B Paint Spray and Chemical hose has been found to be satisfactory. This hose is available from the Gates Corporation (Product No. 3207-0296). 3.1.8. When electing to manually measure rut depths
15、, a rut depth measurement template is required. This template shall be machined aluminum plate approximately 31.7 to 38.1 mm (1.25 to 1.50 in.) thick and have the following dimensions: 400.0 mm (15.75 in.) long by 152.4 mm (6 in.) wide. The rut depth measurement template shall contain five openings,
16、 spaced along the length of the template, in which the ruts are measured. The locations of the openings on the template will coincide with the locations utilized by the automatic measurement system. Each of the five openings shall be approximately 11 mm (0.43 in.) wide. Note 2Manual rut depth measur
17、ements on specimens that are rutted significantly may result in erroneous data. The rut depth measurement template may rest on the displaced material rather than on the test mold. In these cases, the rut depth measurement template should be modified with a channel removed from the bottom side of the
18、 template in order to span the displaced material and ensure that the template rests on the test mold. 3.1.9. The APA shall be calibrated in accordance with Annex A1. 3.2. Ovens for maintaining temperature of plant-produced HMA and preheating specimens. 3.3. Compaction device and molds: 3.3.1. Super
19、pave gyratory compactor (SGC) and compaction molds conforming to T 312, or 3.3.2. Vibratory compactor and compaction molds. 3.3.2.1. Vibratory CompactorA steel-frame device mounted on noise-absorbing isolators and supports that utilizes adjustable vibratory compression forces to consolidate and comp
20、act HMA to produce cylindrical specimens for further testing. The device shall be timer-controlled and capable of 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d T 340-3 AASHTO compacting the speci
21、mens to a specified height and extracting the specimens after compaction. The vibratory compactor shall have a control panel separate from the compaction unit. The panel shall contain a mode switch to control specimen compaction and extraction and a timer to control the compaction-time cycle. 3.3.2.
22、2. The compaction molds used for specimens produced in the vibratory compactor shall be composed of steel with the following dimensions: Inside diameter of 149.9 0.5 mm (5.90 0.02 in.), Inside height of 133.4 0.5 mm (5.25 0.02 in.), Overall height of 152.7 0.5 mm (6.01 0.02 in.), Wall thickness of 7
23、.81 0.5 mm (0.31 0.02 in.), and Bottom plate diameter of 149.0 0.5 mm (5.87 0.02 in.). 4. PREPARATION OF TEST SPECIMENS 4.1. Number and Dimensions of Test SpecimensSix cylindrical specimens, 150 mm (5.91 in.) in diameter by 75 2 mm (3.0 0.1 in.) tall. 4.2. Roadway Core Specimens: 4.2.1. Roadway core
24、 specimens shall be 140 to 152 mm (5.5 to 6.0 in.) in diameter and a minimum of 50 mm (2 in.) tall with all surfaces of the perimeter perpendicular to the surface of the core within 5 mm (0.2 in.). Cores taller than the desired height shall be trimmed with a saw to a height of 75 2 mm (3.0 0.1 in.).
25、 For cores with diameters between 140 and 152 mm (5.5 and 6.0 in.) or heights between 50 and 73 mm (2.0 and 2.9 in.), plaster of paris or comparable material may be used to achieve the proper testing height of 75 2 mm (3.0 0.1 in.) and to ensure that specimens with small diameters fit snugly within
26、the testing mold. Testing shall be conducted on the uncut face of the core. 4.3. Plant-Produced (HMA): 4.3.1. Samples of plant-produced HMA shall be obtained in accordance with T 168. HMA samples shall be reduced to the appropriate test size and compacted while the HMA is within the compaction tempe
27、rature range as determined by the specifying agency. Reheating of loose plant HMA should be avoided. 4.3.2. When using an SGC, compact specimens conforming to the dimensional requirements of Section 4.1 to 7.0 0.5 percent air voids in accordance with T 312. 4.3.3. When using a vibratory compactor, c
28、ompact specimens conforming to the dimensional requirements of Section 4.1 to 7.0 0.5 percent air voids in accordance with the following procedure: 4.3.3.1. Attach and level the appropriate compaction head to the vibrating assembly in accordance with the manufacturers instructions. Verify that the c
29、ompaction head is correctly attached and arranged to produce a specimen of the desired height. Check the position of the compaction head against the specimen mold in accordance with the manufacturers instructions. 4.3.3.2. Adjust the compaction force and vibration time settings in accordance with th
30、e manufacturers instructions. 4.3.3.3. Heat and charge the specimen mold in accordance with the manufacturers instructions. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d T 340-4 AASHTO 4.3.3.4. O
31、perate the vibratory compactor in order to compact and extrude the specimen in accordance with the manufacturers instructions. 4.3.4. Compacted specimens should remain at room temperature, approximately 25C (77F), to allow the entire specimen to cool, for a minimum of 3 h. 4.4. Laboratory-Prepared (
32、HMA): 4.4.1. Prepare the ingredient materials and mix the HMA specimens in accordance with T 312. 4.4.2. When using an SGC, compact specimens conforming to the dimensional requirements of Section 4.1 to 7.0 0.5 percent air voids in accordance with T 312. 4.4.3. When using a vibratory compactor, comp
33、act specimens conforming to the dimensional requirements of Section 4.1 to 7.0 0.5 percent air voids in accordance with the procedure given in Sections 4.3.3.1 through 4.3.3.4. 4.4.4. Compacted specimens should remain at room temperature, approximately 25C (77F), to allow the entire specimen to cool
34、, for a minimum of 3 h. 5. DETERMINING THE AIR VOID CONTENT 5.1. Determine the bulk specific gravity of the HMA specimens in accordance with T 166. In the case of sawn specimens as described in Section 4.2.1, determine the bulk specific gravity of the specimens after sawing. 5.2. Determine the maxim
35、um specific gravity of the loose HMA in accordance with T 209. 5.3. Determine the air void content of the HMA specimens in accordance with T 269. 6. SELECTING THE TEST TEMPERATURE 6.1. The test temperature shall be set to the high temperature of the standard Superpave performance-graded (PG) binder
36、identified by the specifying agency for the project for which the HMA is intended. For circumstances where the high-temperature binder grade has been increased, the APA test temperature will remain at the standard PG binder high temperature. 7. SPECIMEN PREHEATING 7.1. Place the specimens in the tes
37、t molds. 7.2. Specimens shall be preheated at the test temperature in the temperature-calibrated APA test chamber or a separate calibrated oven for a minimum of 6 h. Specimens should not be held at the test temperature for more than 24 h prior to testing. 8. PROCEDURE 8.1. Set the hose pressure gap
38、reading to 690 35 kPa (100 5 psi). Set the load cylinder pressure reading for each wheel to achieve a load of 445 22 N (100 5 lbf). 8.2. Stabilize the testing chamber temperature at the temperature selected in Section 6. 2015 by the American Association of State Highway and Transportation Officials.
39、All rights reserved. Duplication is a violation of applicable law.TS-2d T 340-5 AASHTO 8.3. Secure the preheated, molded specimens in the APA. The preheated APA chamber should not be open for more than 6 min when securing the test specimens into the machine. Close the chamber doors and allow a minim
40、um of 10 min for the temperature to stabilize prior to starting the test. 8.4. Manual Rut-Depth Measurement: 8.4.1. Apply 25 cycles to seat the specimens before taking the initial measurements. Make adjustments to the hose pressure as needed during these 25 cycles. 8.4.2. Open the chamber doors; unl
41、ock and pull out the sample holding tray. 8.4.3. Place the rut-depth-measurement template conforming to Section 3.1.8 over the specimen. Ensure that the rut-depth-measurement template is properly seated and firmly rests on top of the testing mold. 8.4.4. Zero the measuring gauge. Take initial readin
42、gs at each of the four outside locations on the template; the center measurement is not used. Measurements shall be determined by placing the measuring gauge in the template slots and sliding the gauge slowly across each slot. Record the smallest measurement for each location to the nearest 0.01 mm
43、(0.0004 in.). 8.4.5. Repeat Sections 8.4.3 and 8.4.4 for each set of cylinders in the testing position. All measurements shall be completed within 6.0 0.5 min. 8.4.6. Push the sample holding tray in and secure it. Close the chamber doors and allow a minimum of 10 min for the temperature to stabilize
44、. 8.4.7. Set the preset counter to 8000 cycles. 8.4.8. Start the test. When the test reaches 8000 cycles, the APA will stop and the load wheels will automatically retract. 8.4.9. Repeat Sections 8.4.2 through 8.4.5 to obtain the final measurements. 8.5. Automatic Rut-Depth Measurement: Note 3Some AP
45、A users have reported significant differences in rut depths between automatic measurements and manual measurements. 8.5.1. Initialize the APA computer software. Using the APA computer software or on the APA as appropriate, enter the applicable test parameters and project information prior to startin
46、g the test. 8.5.2. Ensure that the cycle-countdown mechanism is set to a value that will permit the specimens to be seated, a complete test of 8000 cycles to be performed, and the computer program to be disengaged at the end of the test. Normally, this value is between 8050 and 8100 cycles. 8.5.3. U
47、sing the APA computer software or on the APA as appropriate, start the test. 8.5.4. The APA will stop when the test is complete, and the wheels will automatically retract. Save the rut-depth data file to the computer. Print the data if desired. 2015 by the American Association of State Highway and T
48、ransportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d T 340-6 AASHTO 9. CALCULATIONS 9.1. Determine the average rut depth for each of the three test positions: 9.1.1. When utilizing manual rut-depth measurement, determine the rut depth at each location by su
49、btracting the final measurement from the initial measurement. Use the rut depth for all four locations to calculate the average rut depth for each of the three test positions. 9.1.2. When utilizing automatic rut-depth measurement, obtain the rut depths from the three test positions as displayed on the APA computer software. 9.2. Outlier EvaluationCalculate the sample standard deviation for the three test positions. If the sample standard deviation of the three test positions is grea
