J.5_AMPT_Equipment_Specification.pdf

Asphalt Mixture Performance Tester (AMPT)

Draft Equipment Specification – April 12, 2016

1. Scope

1.1. The objective of this specification is to define the required attributes for the

Asphalt Mixture Performance Tester (AMPT). The AMPT is a computer automated control and data acquisition system and a, typically servo-hydraulic, servo-pneumatic, or servo-electric test system used to perform the following standard methods of test:

AASHTO T 378 – Standard Method of Test for Determining the

Dynamic Modulus for Asphalt Mixtures using the Asphalt Mixture

Performance Tester (AMPT)

AASHTO TP 107 – Standard Method of Test for Determining the

Damage Characteristics Curve of Asphalt Mixtures Using the Asphalt

Mixture Performance Tester (AMPT)

AASHTO TP 116 – Standard Method of Test for Rutting Resistance of

Asphalt Mixtures using Incremental Repeated Load Permanent

Deformation (iRLPD)

AASHTO TP XXX – Standard Method of Test for Determining the Flow

Number for Asphalt Mixtures using the Asphalt Mixture Performance

Tester (AMPT)

1.2. This specification does not address specific analysis software that will be needed to analyze data collected with the AMPT to produce engineering properties.

NOTE 1 – Refer to the above standard methods of test for specific analysis software that will be needed to analyze data collected with the AMPT and produce the resulting engineering properties.

1.3. This specification does not specify all design details for the AMPT. It is the responsibility of the manufacturer/supplier and the purchaser to ensure that the

AMPT equipment being supplied is appropriate for the intended function.

2. Referenced Standards

2.1. AASHTO T 378 – Standard Method of Test for Determining the Dynamic

Modulus and Flow Number for Asphalt Mixtures using the Asphalt Mixture

Performance Tester (AMPT)

2.2. AASHTO TP 107 – Standard Method of Test for Determining the Damage

Characteristics Curve of Asphalt Mixtures Using the Asphalt Mixture

Performance Tester (AMPT)

2.3. AASHTO TP 116 – Standard Method of Test for Rutting Resistance of Asphalt

Mixtures using Incremental Repeated Load Permanent Deformation (iRLPD)

2.4. AASHTO TP XXX – Standard Method of Test for Determining the Flow

Number for Asphalt Mixtures using the Asphalt Mixture Performance Tester

(AMPT)

2.5. ASTM D 5720 - Standard Practice for Static Calibration of Electronic

Transducer-Based Pressure Measurement Systems for Geotechnical Purposes

2.6. ASTM D 6027 - Standard Practice for Calibrating Linear Displacement

Transducers for Geotechnical Purposes

2.7. ASTM E4 -Standard Practices for Force Verification of Testing Machines

2.8. ASTM E74 - Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines

2.9. ASTM E83- Standard Practice for Verification and Classification of

Extensometer Systems

3. Terminology

3.1. Dynamic Modulus. Ratio of the stress amplitude to the strain amplitude for asphalt concrete subjected to sinusoidal loading.

3.2. Phase Angle. Angle in degrees between a sinusoidally applied stress and the resulting strain in a controlled stress test.

3.3. Resolution. The smallest change of a measurement that can be displayed or recorded by the measuring system. When noise produces a fluctuation in the display or measured value, the resolution shall be a minimum of one-half of the range of the fluctuation.

3.4. Accuracy. The permissible variation from the correct or true value.

3.5. Error. The value obtained by subtracting the value indicated by a traceable calibration device from the value indicated by the measuring system.

3.6. Confining Pressure. Stress applied to all surfaces of the specimen in a confined test.

4. General Equipment Requirements

4.1. The AMPT shall be a complete, fully integrated testing system meeting the requirements of these specifications and having the capability to perform the tests described in AASHTO T 378, TP 107, TP 116, and TP XXX.

4.2. Annex A summarizes the methods to be used to verify that the AMPT complies with the requirements of this specification.

4.3. The AMPT shall include the following components:

4.3.1. Tension-compression loading machine.

4.3.2. Loading platens.

4.3.3. Load measuring system.

4.3.4. Actuator displacement measuring system.

4.3.5. Specimen deformation measuring system.

4.3.6. Confining pressure system.

4.3.7. Environmental chamber.

4.3.8. Computer control and data acquisition system.

4.4. The load frame, environmental chamber, and computer control system for the

AMPT shall occupy a foot-print no greater than 1.5 m (5 ft) by 1.5 m (5 ft) with a maximum height of 1.8 m (6 ft). A suitable frame, bench or cart shall be provided so that the bottom of the test specimen, and the computer keyboard and display are approximately 90 cm (36 in) above the floor.

4.5. The load frame, environmental chamber and computer control system for the

AMPT shall operate on 120 or 208 VAC, 60 Hz electrical power.

4.6. If a hydraulic power supply is required, it shall occupy a foot-print no larger than

1 m (3 ft) by 1.5 m (5 ft). The noise level 2 m (6.5 ft) from the hydraulic power supply shall not exceed 70 dB. The hydraulic power supply shall operate on 120 or 208 VAC 60 Hz electrical power.

4.7. When disassembled, the width of any single component shall not exceed 76 cm

(30 in).

4.8. Air supply requirements shall not exceed 0.005 m3/s (10.6 ft3/min) at 850 kPa

(125 psi).

4.9. The AMPT shall include appropriate limit and overload protection.

4.10. An emergency stop shall be mounted at an easily accessible point on the system.

5. Equipment

5.1. Tension-Compression Loading Machine

5.1.1. The AMPT shall have closed-loop load control with the capability of applying constant, ramp, sinusoidal, and pulse loads. The requirements for each of these modes are listed in the table below.

Type of Loading Capacity Rate

Ramp 10 kN (2.25 kips) 0.5 sec ramp

Pulse 8 kN (1.80 kips) 10 Hz pulse with

0.9 sec dwell

Sinusoidal 13.5 kN (3.0 kips) 0.01 to 25 Hz

5.1.2. The AMPT shall have the capability to provide continuous loading through zero in both load and actuator displacement control.

5.1.3. For ramp and constant loads, the load shall be maintained within +/- 2 percent of the desired load.

5.1.4. For sinusoidal loads, the standard error of the applied load shall be less than 10 percent. The standard error of the applied load is a measure of the difference between the measured load data, and the best fit sinusoid. The standard error of the load is defined in Equation 1.

o n i ii xn xx

Pse ˆ

%100

ˆ

)( 1

(1)

Where:

se(P) = Standard error of the applied load xi = Measured load at point i ix̂ = Predicted load at point i from the best fit sinusoid ox̂ = Amplitude of the best fit sinusoid n = Total number of data points collected during test.

NOTE 2 – Refer to AASHTO T 378 for determining the best fit sinusoid.

5.1.5. For pulse loads, the peak of the load pulse shall be within +/- 2 percent of the specified value and the standard error of the applied load during the sinusoidal pulse shall be less than 10 percent.

5.1.6. The machine shall have the capability to load in tension and compression with the loading platens held parallel to one another. The machine shall also have the capability to load in compression through a convex loading surface that allows rotation of the upper loading platen. The center of the seating surface shall coincide with the center of the specimen end.

NOTE 3– A convex loading plate or a ball joint have been used to meet the requirement of 5.1.6.

5.2. Loading Platens

5.2.1. The loading platens shall be fabricated from hardened or plated steel or anodized aluminum. The platens shall have yield strength, Young’s modulus, and hardness properties equal to or greater than those for 6061-

T6 aluminum.

5.2.2. The loading platens shall be at least 25 mm (1 in) thick. The diameter of the loading platens shall not be less than 100 mm (3.94 in) nor greater than

105 mm (4.125 in).

5.2.3. The loading platens shall not depart from a plane by more than 0.0125 mm

(0.0005 in) across any diameter.

5.2.4. Compression loading platens shall be smooth.

5.2.5. Tension loading platens may be grooved to improve the overall adhesion between the glue and the loading platens.

NOTE 4– It is recommended that if grooved, the grooves be approximately 0.5 mm (0.02 in) deep and spaced laterally by a distance of approximately 1.9 mm (0.075 in). The grooving pattern can be either concentric circles or a spiral pattern. A V-shaped groove or a cross-hatched groove is suggested. The 60 degree point threading bit has been used successfully for making the grooves.

5.3. Load Measuring System

5.3.1. The AMPT shall include an electronic load measuring system with full scale range equal to or greater than the stall force for the actuator of the compression-tension loading machine.

5.3.2. The load measuring system shall have an error equal to or less than +/- 1 percent for loads ranging from 0.12 kN (27 lb) to 13.5 kN (3.0 kips) when verified in accordance with ASTM E4.

NOTE 5- Section 5.3.2 requires the load cell to be rated at 0.01% of full scale, if full scale is 13.5 kN, in order to meet the +/- 1 percent requirement at the 0.12 kN load level.

5.3.3. The resolution of the load measuring system shall comply with the requirements of ASTM E4.

5.4. Actuator Displacement Measuring System

5.4.1. The AMPT shall include an electronic actuator displacement measuring system that measures the movement of the loading actuator.

5.4.2. The actuator displacement measuring system shall have a range of at least

12 mm (0.5 in).

5.4.3. The actuator displacement measuring system shall have a resolution equal to or better than 0.0025 mm (0.0001 in).

5.4.4. The actuator displacement measuring system shall have an error equal to or less than 0.03 mm (0.001 in) over the 12 mm range when verified in accordance with ASTM D 6027.

5.4.5. The actuator displacement measuring system shall be designed to minimize errors due to compliance and/or bending of the loading mechanism. These errors shall be less than 0.25 mm (0.01 in) at 8 kN (1.8 kips) load.

5.5. Specimen Deformation Measuring System

5.5.1. The AMPT shall include a glued gauge point system for measuring deformations on the specimen over a gauge length of 70 mm (2.76 in) 1 mm (0.04 in) at the middle of the specimen.

5.5.2. The specimen deformation measuring system shall include at least two transducers spaced equally around the circumference of the specimen.

When more than two transducers are used they shall be spaced equally around the circumference.

NOTE 6 – Using four transducers set at 90 degrees apart has an advantage over using fewer transducers because if one transducer does not function properly, data from that transducer and the transducer 180 degrees opposed to it can be discarded and the remaining two sensor used to determine the average specimen deformation.

5.5.3. Figure 1 shows a schematic of the standard specimen deformation measuring system with critical dimensions. Other properties of the deformation measuring system are listed below.

Property Value

Gauge point contact area 80 mm2 10 mm2

Dimension of the gauge point in the direction of the gauge length 10mm 2mm

Mass of mounting system and transducer 80 g max

Transducer spring force 1 N max

NOTE 7 – For TP 107 testing and T 378 dynamic modulus tests at high temperatures, it may be necessary to use transducers with lower spring force to minimize gauge point movement. Gauge point movement can be monitored by placing an instrumented specimen on its side at the test temperature and checking that no deformation is measured over a 20 minute interval after thermal equilibrium has been achieved.

Figure 1. Schematic of Standard Specimen Mounted Deformation Measuring

System.

70 mm +/- 1 mm

10 mm(max)

SPECIMEN

GLUED GAGE POINT

SEE 9.2 FOR AREA

CL

10 mm

2 mm

10 mm

2 mm

5.5.3 FOR AREA

5.5.4. The transducers shall have a range of at least 1 mm (0.04 in).

5.5.5. The transducers shall have a resolution equal to or better than 0.0002 mm

(7.8 micro inch).

5.5.6. The transducers shall have an error equal to or less than 0.0025 mm

(0.0001 in) over the 1 mm range when verified in accordance with ASTM

D 6027.

5.5.7. The specimen deformation measuring system shall be designed for rapid specimen installation and subsequent testing. Specimen instrumentation, installation, application of confining pressure, and temperature equilibration shall take no longer than 5 minutes over the complete range of temperatures.

5.6. Confining Pressure System

5.6.1. The confining pressure system shall be capable of providing a constant confining pressure up to 210 kPa (30 psi) to the test specimen. The system shall include a pressure cell with appropriate pressure regulation and control, a flexible specimen membrane, a device or method for detecting leaks in the membrane, a pressure transducer, and a temperature sensing device that is mounted internal to the cell.

5.6.2. The confining pressure cell shall be designed to allow the operator to view the specimen, the specimen mounted deformation measuring system, and the specimen end platens during testing.

5.6.3. Confining pressure shall be controlled by the computer control and data acquisition system. The confining pressure control system shall have the capability to maintain a constant confining pressure throughout the test within +/- 2 percent of the desired pressure.

5.6.4. The specimen shall be enclosed in an impermeable flexible membrane sealed against the loading platens.

5.6.5. The pressure inside the specimen membrane shall be maintained at atmospheric pressure through vents in the loading platens. The system shall include a device or method for detecting membrane leaks.

5.6.6. The confining pressure system shall include a pressure transducer for recording confining pressure during the test. The pressure transducer shall have a range of at least 210 kPa, (30 psi) and a resolution of 0.5 kPa (0.07 psi). The pressure transducer shall have an error equal to or less than 1 percent of the indicated value over the range of 35 kPa (5 psi) to 210 kPa

(30 psi) when verified in accordance with ASTM D5720.

5.6.7. A suitable temperature sensor shall be mounted at the mid-height of the specimen in the pressure cell between the specimen and the cell wall. This temperature sensor shall have a range of 0 to 80 oC (32 to 176 oF), and be readable and accurate to the nearest 0.25 oC. (0.5 oF). For confined tests this sensor shall be used to control the temperature in the chamber, and provide a continuous reading of temperature that will be sampled by the data acquisition system during the test.

5.6.8. The confining pressure system shall be designed for rapid installation of the test specimen in the confining cell and subsequent equilibration of the chamber temperature to the target test temperature. Specimen instrumentation, installation, application of confining pressure, and temperature equilibration shall take no longer than 5 minutes over the complete range of temperatures.

5.7. Environmental Chamber

5.7.1. The environmental chamber shall be capable of controlling temperatures inside the chamber over the range from 4 to 70 oC (39 to 158 oF) within

+/- 0.5 oC (1 F), when room temperature is between 15 and 27 C (60 and

80 F).

5.7.2. The environmental chamber need only be large enough to accommodate the test specimen. It is envisioned that specimens will be preconditioned in a separate chamber that is large enough to hold the number of specimens needed for a particular project along with one or more dummy specimens with internally mounted temperature sensors.

5.7.3. The environmental chamber shall be designed to allow the operator to view the specimen, the specimen mounted deformation measuring system, and the specimen end platens during testing.

5.7.4. The environmental chamber shall be designed for rapid installation of the test specimen and subsequent equilibration of the environmental chamber temperature to the target test temperature. Specimen instrumentation, installation, application of confining pressure, and temperature equilibration shall take no longer than 5 minutes over the complete range of temperatures, when room temperature is between 15 and 27 C (60 and

80 F).

5.7.5. A suitable temperature sensor shall be mounted in the environmental chamber within 25 mm (1 in) of the specimen at the mid-height of the specimen. This temperature sensor shall have a range of at least 0 to 80 oC

(32 to 176 oF), and be readable and accurate to the nearest 0.25 oC (0.5 oF).

This sensor shall be used to control the temperature in the chamber, and provide a continuous reading of temperature that will be sampled by the data acquisition system during the test.

5.8. Computer Control and Data Acquisition System

5.8.1. The AMPT shall be electronically controlled with a computer or controller that operates software specifically designed to conduct the tests described in

AASHTO TP79, AASHTO TP 107, AASHTO TP 116, AASHTO TP XXX.

5.8.2. The AMPT shall provide the capability to control and record, the following within the tolerances described in AASHTO T 378, AASHTO

TP 107, AASHTO TP 116, and AASHTO TP XXX.

1. Load,

2. Actuator displacement,

3. Confining pressure, and

4. Temperature.

5.8.3. The AMPT shall provide the capability to record the specimen deformation measuring sensors as required by AASHTO T 378 and

AASHTO TP 107.

5.8.4. The AMPT shall provide the capability to record data from each channel at rates between 0.25 and 1,250 sample per sec.

5.8.5. The AMPT shall have the capability to apply constant, ramp, and sinusoidal loading in load and actuator displacement control.

5.8.6. The AMPT shall have the capability to change between load and actuator displacement control without changing the actuator position or the load on the test specimen.

5.8.7. In sinusoidal load control, the AMPT shall have the capability to adjust the target load amplitude based on strains calculated from the specimen mounted deformation measuring system.

5.8.8. The AMPT software shall provide the option for user selection of SI or US

Customary units.

6. Calibration and Verification of Dynamic Performance

6.1. Prior to shipment, the complete AMPT shall be assembled at the manufacturer’s facility and calibrated. This calibration shall include calibration of the computer control and data acquisition electronics/software, static calibration of the load, actuator displacement, specimen deformation, confining pressure and temperature measuring systems; and verification of the dynamic performance of the load and specimen deformation measuring systems. Calibration procedures are described in Annex B.

6.2. The results of these calibrations shall be documented, certified by the manufacturer, and provided with the system documentation.

6.3. The following systems on the AMPT shall be calibrated annually, when the

AMPT system is moved including initial installation, or when any of its components are changed:

Load Measuring System

Actuator Displacement Measuring System

Specimen-Mounted Deformation Measuring System

Confining Pressure Measuring System

Temperature Measuring System

Calibration procedures are described in Annex B.

6.4. Loading a proving ring or similar verification device in compression with the specimen deformation measuring system attached shall perform verification of the dynamic performance of the force and specimen mounted deformation measuring systems. The manufacturer shall be responsible for fabricating the verification device and shall supply it with the AMPT.

NOTE 8 – AMPTs used for tension testing such as in TP 107 should be calibrated in tension and compression to cover the full range of loading conditions encountered during testing.

6.5. The verification device shall have a static deflection of 0.007 mm 0.0005 mm

(0.00028 in 0.00002 in) at a load of 1.2 kN (0.27 kips) in tension and compression.

6.6. The dynamic performance verification procedure is described in Annex B. All of the dynamic modulus measurements shall be within 2 percent of that determined by static loading of the verification device. The phase difference between load and displacement measurements on the verification device shall be less than 3 degrees.

6.7. The AMPT shall include a calibration mode for subsequent annual calibration in accordance with Annex B. It shall also include a dynamic verification mode to perform the dynamic performance verification in accordance with Annex B.

Access points for calibration work shall be clearly shown in the system reference manual.

7. Documentation

7.1. The AMPT shall include on-line help and documentation.

7.2. A reference manual completely documenting the AMPT shall be provided. This manual shall include the following Chapters:

1. System Introduction.

2. Installation.

3. Tension-Compression Loading System.

4. Loading Platens. Section shall specify materials used to manufacture the loading platens.

5. Load Measuring System.

6. Actuator Displacement Measuring System.

7. Specimen Deformation Measuring System.

8. Confining Pressure System.

9. Environmental Chamber.

10. Control and Data Acquisition System.

11. Flow Number Test, AASHTO TP XXX.

12. Incremental Repeated Load Permanent Deformation Test, AASHTO TP 116

13. Dynamic Modulus Test, AASHTO T 378.

14. Direct Tension Cyclic Fatigue Test, AASHTO TP 107

15. Calibration.

16. Verification of Dynamic Performance.

17. Verification of Normal Operation.

18. Preventative Maintenance.

19. Spare Parts List

20. Drawings.

8. Keywords

Asphalt Mixture Performance Tester (AMPT), dynamic modulus, flow number, incremental repeated load permanent deformation (iRLPD), viscoelastic continuum damage (VECD)

9. References

None

ANNEX A— SPECIFICATION COMPLIANCE TESTS

(Mandatory Information)

A1. PURPOSE

A1.1. This Annex describes tests to verify that the AMPT is in compliance with this equipment specification.

A2. SUMMARY

A2.1. Methods for verifying that various components of the AMPT are in compliance with this equipment specification are provided.

A3. PROCEDURE

A3.1. The specification compliance tests and methods are listed below.

A3.2. Perform each of the specification compliance tests and document the results.

A3.3. If the specification compliance testing reveals that any component of the AMPT is not in compliance with this equipment specification, contact the manufacturer to resolve the deficiency.

Item Section Method

Assembled Size 4.4 and 4.6 Measure

Specimen and Display Height 4.4 Measure

Component Size 4.7 Measure

Electrical Requirements 4.5 and 4.6 Documentation and trial

Air Supply Requirements 4.8 Documentation and trial

Limit Protection 4.9 Documentation and trial

Emergency Stop 4.10 Documentation, visual inspection, trial

Loading Machine Capacity 5.1.1 Independent force verification (See Annex B)

Load Control Capability 5.1.2 through

5.1.5

Trial tests on manufacturer provided dynamic verification device.

Platen Configuration 5.1.6 Visual

Platen Materials 5.2.1 Documentation

Platen Dimensions 5.2.2 Measure

Platen Flatness 5.2.3 Measure

Platen Smoothness or Grooves 5.2.4 and 5.2.5 Measure

Load Cell Range 5.3.1 Load cell data plate

Load Accuracy 5.3.2 Independent force verification (See Annex B)

Load Resolution 5.3.3 Independent force verification (See Annex B)

Configuration of Actuator

Displacement Measuring System

5.4.1 Visual

Transducer Range 5.4.2 Independent deflection verification (See Annex B)

Transducer Resolution 5.4.3 Independent deflection verification (See Annex B)

Transducer Accuracy 5.4.4 Independent deflection verification (See Annex B)

Item Section Method

Load Mechanism Compliance and

Bending

5.4.5 Measure on steel specimens with various degrees of lack of parallelism

Configuration of Specimen

Deformation Measuring System

5.5.1 through

5.5.3

Visual

Gauge Length of Specimen

Deformation Measuring System

5.5.1 Measure

Transducer Spring Force 5.5.3 Documentation and measure by displacing against a scale

Transducer Range 5.5.4 Independent deflection verification (See Annex B)

Transducer Resolution 5.5.5 Independent deflection verification (See Annex B)

Transducer Accuracy 5.5.6 Independent deflection verification (See Annex B)

Specimen Deformation System

Complexity

5.5.7 Trial

Confining Pressure Range 5.6.1 and 5.6.6 Independent pressure verification (See Annex B)

Confining Pressure Control 5.6.3 Trial tests on asphalt specimens

Confining Pressure System

Configuration

5.6.2, 5.6.4, and 5.6.5

Visual

Confining Pressure Resolution and Accuracy

5.6.6 Independent pressure verification (See Annex B)

Temperature Sensor 5.6.1 and 5.6.7 Independent temperature verification (See Annex B)

Specimen Installation and

Equilibration Time

5.5.7, 5.6.8, and 5.7.4

Trial

Environmental Chamber Range and Control

5.7.1 Independent temperature verification (See Annex B)

Computer Control and Data

Acquisition

5.8 Documentation and trial

Initial Calibration and Dynamic

Performance Verification

6 Certification and independent verification

Calibration Mode 6.8 Trial

Verification of Normal Operation

Procedures and Equipment

6.8 Review

On-line Documentation 7.1 Trial

Reference Manual 7.2 Review

ANNEX B—PROCEDURES FOR CALIBRATING THE AMPT

(Mandatory Information)

B1. PURPOSE

B1.1. This Annex presents procedures for calibrating the measuring systems on the AMPT.

A4. SUMMARY

B4.1. The following components of the AMPT are calibrated using the procedures contained in this Annex:

1. Load Measuring System

2. Actuator Displacement Measuring System

3. Specimen-Mounted Deformation Measuring System

4. Confining Pressure Measuring System

5. Temperature Measuring System

B5. REFERENCED STANDARDS

B5.1. ASTM Standards:

1. D5720, Standard Practice for Static Calibration of Electronic Transducer-Based

Pressure Measurement Systems for Geotechnical Purposes

2. D6027, Standard Test Method for Calibrating Linear Displacement Transducers for

Geotechnical Purposes (Withdrawn 2013)

3. E4, Standard Practices for Force Verification of Testing Machines

4. E74, Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines

5. E83, Standard Practice for Verification and Classification of Extensometer Systems

B6. PROCEDURE

B6.1. Load Measuring System Calibration:

B6.1.1. The load measuring system shall have a maximum error of 1 percent of the indicated value over the range of 0.12 kN (25 lb) to 13.5 kN (3.0 kips) when verified in accordance with ASTM E4.

B6.1.2. The resolution of the load measuring system shall comply with the requirements of

ASTM E4.

B6.1.3. Perform load measuring system verification in accordance with ASTM E4.

B6.1.4. All calibration load cells used for the load calibration shall be certified according to

ASTM E74 and shall not be used below their Class A loading limits.

B6.1.5. When performing the load verification, apply at least two verification runs of at least five loads throughout the range selected.

B6.1.6. If the initial verification loads are within ±1 percent of the reading, these values can be applied as the as-found values, and the second set of verification forces can be used as the final values. Record return-to-zero values for each set of verification loads.

B6.1.7. If the initial verification loads are out of tolerance, calibration adjustments shall be made according to the manufacturer’s specifications until the values are established within the

ASTM E4 recommendations. Two applications of verification loads shall then be applied to determine the acceptance criteria for repeatability according to ASTM E4.

B6.1.8. At no time will correction factors be applied to corrected values that do not meet the accuracy requirements of ASTM E4.

B6.2. Actuator Displacement and Specimen-Mounted Deformation Measuring Systems

Calibration:

B6.2.1. The actuator displacement measuring system shall have a minimum resolution of 0.0025 mm (0.0001 in.).

B6.2.2. The actuator displacement measuring system shall have a maximum error of 0.03 mm

(0.001 in.) over the 12-mm (0.47-in.) range when verified in accordance with ASTM

D6027.

B6.2.3. The specimen-mounted deformation measuring system shall have a minimum resolution of 0.0002 mm (7.8 in.).

B6.2.4. The specimen-mounted deformation measuring system shall have a maximum error of

0.0025 mm (0.0001 in.) over the 1-mm (0.04-in.) range when verified in accordance with

ASTM D6027.

B6.2.5. Perform verification of the actuator displacement and specimen-mounted deformation measuring systems in accordance with ASTM D6027.

B6.2.6. The micrometer used shall conform to the requirements of ASTM E83.

B6.2.7. When performing verification of the actuator displacement and specimen-mounted deformation measuring systems, each transducer and associated electronics must be verified individually throughout its intended range of use.

B6.2.8. Mount the appropriate transducer in the micrometer stand and align it to prevent errors caused by angular application of measurements.

B6.2.9. Apply at least five verification measurements to the transducer throughout its range.

Rezero and repeat the verification measurements to determine repeatability.

B6.2.10. If the readings of the first verification do not meet the specified error tolerance, perform calibration adjustments according to manufacturer’s specifications and repeat the applications of measurement to satisfy the error tolerances.

B6.3. Confining Pressure Measuring System Calibration:

B6.3.1. The confining pressure measuring system shall have a minimum resolution of 0.5 kPa

(0.07 psi).

B6.3.2. The confining pressure measuring system shall have a maximum error of 1 percent of the indicated value over the range of 35 kPa (5 psi) to 210 kPa (30 psi) when verified in accordance with ASTM D5720.

B6.3.3. Perform verification of the confining pressure measuring system in accordance with

ASTM D5720.

B6.3.4. All calibrated pressure standards shall meet the requirements of ASTM D5720.

B6.3.5. Attach the pressure transducer to the pressure standardizing device.

B6.3.6. Apply at least five verification pressures to the device throughout its range and record each value. Determine if the verification readings fall within ±1 percent of the value applied.

B6.3.7. If the readings are within tolerance, apply a second set of readings to determine repeatability. Record the return-to-zero values for each set of verification pressures.

B6.3.8. If the readings are out of tolerance, adjust the device according to the manufacturer’s specifications and repeat the dual applications of pressure as described above to complete verification.

B6.4. Temperature Measuring System Calibration:

B6.4.1. The temperature measuring system shall be readable and accurate to the nearest 0.25°C

(0.5°F).

B6.4.2. Verification of the temperature measuring system shall be performed using an NIST-traceable reference thermal detector that is readable and accurate to 0.1°C (0.2°F).

B6.4.3. A rubber band or O-ring will be used to fasten the reference thermal detector to the system temperature sensor.

B6.4.4. Comparisons of the temperature from the reference thermal detector and the system temperature sensor shall be made at six temperatures over the operating range of the environmental chamber.

B6.4.5. Once equilibrium is obtained at each temperature setting, record the temperature of the reference thermal detector and the system temperature sensor.

B6.4.6. If the readings are out of the specified tolerance, adjust the device according to the manufacturer’s specifications and repeat the measurements as described above to complete verification.

B6.5. Dynamic Performance Verification:

B6.5.1. The verification of the dynamic performance of the equipment shall be performed after calibration of the system.

B6.5.2. The dynamic performance verification shall be performed using the verification device provided with the system by the manufacturer.

B6.5.3. First, measure and record the modulus of the verification device for a diameter of 100 mm (4 in.) under static loading conditions using applied stresses of 65, 575, 1100, and

1600 kPa (10, 85, 160, and 230 psi).

B6.5.4. Then, use the verification device to simulate the dynamic modulus test conditions.

Measure the dynamic modulus of the verification for a diameter of 100 mm (4 in.) using applied stresses of 65, 575, 1100, and 1600 kPa (10, 85, 160, and 230 psi) at frequencies of 0.1, 1, and 10 Hz (a total of 12 measurements).

B6.5.5. The 12 moduli from the dynamic loading shall be within ±2 percent of that value obtained for the same stress level from the static measurement. The 12 phase angles from the dynamic loading shall be less than ±1 degree.