Long-Term Pavement Performance Materials Characterization Program: Verification of Dynamic Test Systems With An Emphasis On Resilient Modulus

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Foreword

As part of the Federal Highway Administration’s (FHWA) Long-Term Pavement Performance (LTPP) program materials characterization effort, a quality control/quality assurance (QC/QA) procedure was developed to verify the ability of the laboratory equipment and personnel to perform LTPP Protocol P46 resilient modulus testing. This effort is documented in report FHWA-RD-96-176, Resilient Modulus of Unbound Materials (LTPP Protocol P46) Laboratory Startup and Quality Control Procedures.

Since the issuance of that report in February 1997, a great deal of experience has been gathered in using the procedure. The purpose of this document is to further expand the concepts introduced in FHWA-RD-96-176 and incorporate the lessons learned in the past few years. In addition, the procedures documented in this report have been written in a more generic sense so that their use can be more broadly applied in the materials characterization industry. While the procedures outlined herein are principally designed to verify resilient modulus testing operations within a laboratory, extension of these concepts to other test procedures can be made with little or no modification.

The implementation of FHWA-RD-96-176 has had a great impact on achieving repeatable, reliable, high-quality resilient modulus data for the LTPP program. It is envisioned that the broader application of these procedures and processes in other test programs may bring a benefit to a broader community interested in the acquisition of accurate, repeatable test results from dynamic test systems.

Gary L. Henderson
Director, Office of Infrastructure
Research and Development

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Table of Contents

1. Introduction
   • General
   • Structure and Use
   • Who Should Use the Procedure
   • When the Procedure Should Be Used
   • Benefits of Use
   • Disclaimer
2. GENERAL EQUIPMENT REQUIREMENTS
3. ELECTRONIC SYSTEMS PERFORMANCE VERIFICATION PROCEDURE
   • Introduction
   • Background
   • Dynamic System Test Configuration
   • Approach
   • Acceptance Criteria
   • Discussion
   • Example
4. CALIBRATION CHECK AND OVERALL SYSTEM PERFORMANCE VERIFICATION PROCEDURE
   • Introduction
   • Deformation Measurement Devices
   • Load Cell Zero
   • Load Cell Calibration
   • Verification of Load Cell Calibration (Static)
   • Load versus Deformation Response Check (Dynamic)
   • System Dynamic Response Check
   • Triaxial Pressure Chamber
   • Environmental Chamber
5. PROFICIENCY PROCEDURE
   • Background
   • Dynamic System Configuration
   • Approach
   • Discussion
   • Example
6. SUMMARY

APPENDIX A. SAMPLE DATA COLLECTION FORMS

APPENDIX B. DETERMINATION OF PHASE ANGLE

LIST OF FIGURES

1. Graph. Sample electrical schematic of voltage divider.
2. Chart. Example of micrometer reading versus displacement.
3. Graph. Sample 445 N proving ring loading pattern.
4. Graph. Example of proving ring versus load cell check.
5. Graph. Example of proving ring versus LVDT check.
6. Graph. Example of load pulse analysis.
7. Graph. Example of deformation response analysis.
8. Graph. Sample results of dynamic haversine check, 445 N load cell.
9. Graph. Example of system dynamic response check of 445 N proving ring, 1 Hz.
10. Graph. Example of load versus time check.
11. Graph. Example of deformation response analysis, type 1.
12. Graph. Example of P46 type 1 (base/subbase) results.
13. Form. Sample checklist for base/subbase proficiency procedure.
14. Form. Sample form 1—data collection channel check.
15. Form. Sample form 2—determination of load cell zero reading.
16. Form. Sample form 3—load cell check.
17. Form. Sample form 4—dynamic load versus deformation check.
18. Form. Sample form 5—triaxial cell check.
19. Form. Sample form 6—environmental chamber check.
20. Form. Sample form 7—checklist for proficiency procedure
21. Form. Sample form 8—checklist for asphalt proficiency procedure

LIST OF TABLES

1. Example load cell channel attenuation and time delay.
2. Example of LVDT conditioner attenuation and time delay.
3. Example of summary results for electronics check.
4. Sample of deformation calibration verification dataset.
5. Load cell zero example.
6. Sample static loading parameters.
7. Sample loading specification for 445 N proving ring.
8. Sample results of static load testing of 445 N load cell.
9. Example of inside versus outside deformation readings.
10. Example of subgrade loading parameters.
11. Example of subgrade dynamic loading parameters.
12. Example base/subbase loading parameters.
13. Example of subgrade dynamic loading parameters.
14. Example of asphalt concrete dynamic testing parameters.
15. Example of load versus deformation time delay results.
16. Example of summary dynamic loading results.
17. Example of deformation balance check results.
18. Example of dynamic response acceptance results.
19. Sample phase angle test results.
20. Example of pressure test results.
21. Example of environmental chamber test results.
22. Sample results of load pulse and deformation response analysis.
23. Sample results of calculation verification.
24. Sample results of conformance checks.
25. Sample results of LVDT coefficient of variance (CV) check.
26. Sample results of LVDT ratio check.