ufc_3_260_03_2001.pdf

UFC 3-260-03

15 April 2001

UNIFIED FACILITIES CRITERIA (UFC)

AIRFIELD PAVEMENT EVALUATION

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

UNIFIED FACILITIES CRITERIA (UFC)

AIRFIELD PAVEMENT EVALUATION

Any copyrighted material included in this UFC is identified at its point of use.

Use of the copyrighted material apart from this UFC must have the permission of the copyright holder.

U.S. ARMY CORPS OF ENGINEERS (Preparing Activity)

NAVAL FACILITIES ENGINEERING COMMAND

AIR FORCE CIVIL ENGINEER SUPPORT AGENCY

Record of Changes (changes are indicated by \1\ ... /1/)

Change No. Date Location

This UFC supersedes TM 5-826-1/AFM 88-24, Chap 1, dated August 1988; TM 5-826-2/AFM 88- 24, Chap. 2, dated December 1990; TM 5-826-3/AFM 88-24, Chap. 3, dated December 1990; TM 5- 826-4, dated February 1980; TI 826-01/AFMAN 32-1121V1(I)/NAVFAC DM 21.7, dated August 1999;

and AFJMAN 32-1036, dated August 1988.

FOREWORD

\1\ The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides planning, design, construction, sustainment, restoration, and modernization criteria, and applies to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance with USD(AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and work for other customers where appropriate. All construction outside of the United States is also governed by Status of forces Agreements (SOFA), Host Nation Funded Construction Agreements (HNFA), and in some instances, Bilateral Infrastructure Agreements (BIA.)

Therefore, the acquisition team must ensure compliance with the more stringent of the UFC, the SOFA, the HNFA, and the BIA, as applicable.

UFC are living documents and will be periodically reviewed, updated, and made available to users as part of the Services’ responsibility for providing technical criteria for military construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities Engineering Command (NAVFAC), and Air Force Civil Engineer Support Agency (AFCESA) are responsible for administration of the UFC system. Defense agencies should contact the preparing service for document interpretation and improvements. Technical content of UFC is the responsibility of the cognizant DoD working group. Recommended changes with supporting rationale should be sent to the respective service proponent office by the following electronic form: Criteria Change Request (CCR). The form is also accessible from the Internet sites listed below.

UFC are effective upon issuance and are distributed only in electronic media from the following source:

• Whole Building Design Guide web site http://dod.wbdg.org/.

Hard copies of UFC printed from electronic media should be checked against the current electronic version prior to use to ensure that they are current.

AUTHORIZED BY:

DONALD L. BASHAM, P.E.

Chief, Engineering and Construction U.S. Army Corps of Engineers

DR. JAMES W WRIGHT, P.E.

Chief Engineer Naval Facilities Engineering Command

KATHLEEN I. FERGUSON, P.E.

The Deputy Civil Engineer DCS/Installations & Logistics Department of the Air Force

Dr. GET W. MOY, P.E.

Director, Installations Requirements and Management Office of the Deputy Under Secretary of Defense (Installations and Environment) http://www.wbdg.org/pdfs/ufc_implementation.pdf http://www.wbdg.org/ccb/browse_cat.php?o=29&c=4 http://dod.wbdg.org/

15 Apr 01 i

CONTENTS

Page

CHAPTER 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Paragraph 1. PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

3. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

4. UNITS OF MEASUREMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

5. TYPES OF PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

CHAPTER 2. EVALUATION CONCEPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Paragraph 1. RELATION OF DESIGN TO EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2. CONCEPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

3. EVALUATION PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

4. SITE DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

5. OPERATIONAL CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

6. EVALUATION TESTING METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

7. AIRCRAFT/PAVEMENT CLASSIFICATION NUMBERS (ACN/PCN) . . . . . . . 2-7

8. EVALUATION OF ARMY AIRFIELDS AND HELIPORTS . . . . . . . . . . . . . . . . 2-7

9. EVALUATION OF AIR FORCE AIRFIELDS . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

10. EVALUATION OF NAVY AND MARINE CORPS AIRFIELDS . . . . . . . . . . . . . 2-8

11. SUMMARY OF ARMY EVALUATION REQUIREMENTS . . . . . . . . . . . . . . . . 2-8

12. SUMMARY OF AIR FORCE EVALUATION REQUIREMENTS . . . . . . . . . . . 2-9

13. SUMMARY OF NAVY AND MARINE CORPS EVALUATION

REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

14. FROST-CONDITION EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

15. EMERGENCY CONSTRUCTION EVALUATION . . . . . . . . . . . . . . . . . . . . . 2-10

CHAPTER 3. DATA COLLECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Paragraph 1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

2. STUDY OF EXISTING DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3. COLLECTION OF NDT DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

4. DATA COLLECTION USING DIRECT SAMPLING . . . . . . . . . . . . . . . . . . . . . 3-4

5. SAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

6. LABORATORY TESTS REQUIRED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

CHAPTER 4. PAVEMENT EVALUATION USING NONDESTRUCTIVE TESTING . . . . . . . . . . . . . . . 4-1

Paragraph 1. EVALUATION PRINCIPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

2. PAVEMENT RESPONSE MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

3. PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4. STEP 1 (FEATURE IDENTIFICATION) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

5. STEP 2 (SELECT REPRESENTATIVE DEFLECTION BASIN) . . . . . . . . . . . 4-2

6. STEP 3 (PREDICT LAYER MODULUS VALUES) . . . . . . . . . . . . . . . . . . . . . . 4-3

7. STEP 4 (DETERMINE DESIGN TRAFFIC) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

8. STEP 5 (COMPUTE ALLOWABLE AIRCRAFT LOADS, ALLOWABLE

PASSES, REQUIRED OVERLAY THICKNESS, AND PCN) . . . . . . . . . . . . . . 4-6

ii

CHAPTER 5. EVALUATION OF FLEXIBLE PAVEMENT USING DIRECT SAMPLING . . . . . . . . . . . . 5-1

Paragraph 1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

2. FACTORS LIMITING LOAD-CARRYING CAPACITY . . . . . . . . . . . . . . . . . . . 5-1

3. SELECTION OF THICKNESS VALUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

4. SELECTION OF STRENGTH VALUES FOR SOIL LAYERS . . . . . . . . . . . . . 5-1

5. PASS/LOAD RELATIONSHIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

6. QUALITY OF BITUMINOUS PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

7. EFFECTS OF TRAFFIC COMPACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

8. PAVEMENT CLASSIFICATION NUMBER . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

9. EVALUATIONS FOR ARID REGIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

10. EVALUATIONS FOR FROST CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

11. EVALUATIONS FOR STABILIZED LAYERS . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

CHAPTER 6. EVALUATION OF RIGID PAVEMENTS USING DIRECT SAMPLING . . . . . . . . . . . . . . 6-1

Paragraph 1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

2. FACTORS LIMITING LOAD-CARRYING CAPACITY . . . . . . . . . . . . . . . . . . . 6-1

3. SELECTION OF THICKNESS VALUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

4. SELECTION OF STRENGTH VALUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

5. PLAIN CONCRETE PAVEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

6. REINFORCED CONCRETE PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

7. RIGID OVERLAY ON RIGID PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

8. NONRIGID OVERLAY ON RIGID PAVEMENTS . . . . . . . . . . . . . . . . . . . . . . 6-10

9. RIGID OVERLAY OF FLEXIBLE PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . 6-13

10. COMPOSITE PAVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

11. FIBROUS REINFORCED CONCRETE PAVEMENTS . . . . . . . . . . . . . . . . . 6-14

12. PAVEMENT CLASSIFICATION NUMBER . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14

13. EVALUATIONS FOR FROST CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . 6-14

CHAPTER 7. PAVEMENT EVALUATIONS FOR FROST CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . 7-1

Paragraph 1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

2. FROST CONDITION TERMINOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

3. FROST EFFECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

4. CRITICAL WEAKENING PERIOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

5. EFFECT OF FROST ACTION ON PAVEMENT SURFACE . . . . . . . . . . . . . . 7-3

6. MAGNITUDE OF SUBGRADE WEAKENING . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

7. RECOGNITION OF POTENTIAL FOR DETRIMENTAL FROST ACTION . . . 7-4

8. PAVEMENT EVALUATION-GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

9. DETERMINE DESIGN FREEZING INDEX (DFI) . . . . . . . . . . . . . . . . . . . . . . . 7-4

10. DETERMINE FROST SUSCEPTIBILITY OF BASE, SUBBASE, AND

SUBGRADE LAYERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

11. EVALUATE PAVEMENT FOR COMPLETE FROST PROTECTION . . . . . . . 7-5

12. EVALUATE PAVEMENT FOR LIMITED SUBGRADE FROST

PENETRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

13. EVALUATE PAVEMENT FOR REDUCED SUBGRADE STRENGTH . . . . . . 7-7

14. EVALUATION METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9

15. EXAMPLE 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11

16. EXAMPLE 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

17. EXAMPLE 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13 iii

CHAPTER 8. REPORTING ALLOWABLE WEIGHT BEARING USING THE ACN/PCN

PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

Paragraph 1. GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

2. PCN DETERMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

3. TIRE PRESSURE LIMITATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

4. EVALUATION METHOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

5. CODED REPORTING IN FLIGHT INFORMATION PUBLICATION (FLIP)

OR AIRFIELD INFORMATION PUBLICATION (AIP) DOCUMENTS . . . . . . . 8-3

CHAPTER 9. COMPUTER PROGRAMS FOR PAVEMENT EVALUATION . . . . . . . . . . . . . . . . . . . . . 9-1

Paragraph 1. DEVELOPMENT OF COMPUTER PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . 9-1

2. PROGRAM NAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1

3. OBTAINING PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1

4. USING PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1

APPENDIX A REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

APPENDIX B SAMPLING AND TESTING METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

APPENDIX C HOW TO INSTALL EVALUATION COMPUTER PROGRAMS (LEEP) . . . . . . . . . . . C-1

FIGURES

Figure Title

3-1. Typical airfield layout showing recommended NDT testing frequencies . . . . . . . . . . . . . . . . . 3-11 3-2. NDT equipment configuration for joint load-transfer measurements . . . . . . . . . . . . . . . . . . . . 3-12 3-3. Prediction of pavement temperature for bituminous layers . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13 3-4. Relationship between design pavement temperature and design air temperature . . . . . . . . . 3-14 3-5. General relationship between CBR and modulus of subgrade or base-course reaction . . . . 3-15 3-6. Curves for determining the effective k value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16 4-1. Typical Army airfield layout showing feature identification . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15 4-2. Determination of area beneath deflection basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16 4-3. Procedure for determining the volumetric k value (an estimate of the modulus of subgrade reaction) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17 4-4. Illustration of a layered pavement structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18 4-5. Simplified description of how deflection basins are matched in WESDEF

(one deflection and one layer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19 4-6. Prediction of AC modulus for bituminous layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20 4-7. Limiting horizontal tensile strain criteria for an AC layer in a flexible pavement evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21 4-8. Limiting vertical subgrade strain criteria for flexible pavement evaluation . . . . . . . . . . . . . . . 4-22 4-9. Design factor versus coverages for rigid pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23 4-10. Gear configurations for several typical aircraft with controlling wheels and recommended evaluation positions indicated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24 4-11. Load reduction factors for load-transfer analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25 4-12. Typical WESPAV output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26 5-1. Flexible pavement evaluation curve for UH-60, Type A traffic area . . . . . . . . . . . . . . . . . . . . . 5-9 5-2. Flexible pavement evaluation curve for UH-60, Types B and C traffic areas . . . . . . . . . . . . . 5-10 iv

5-3. Flexible pavement evaluation curves for CH-47, Type A traffic area . . . . . . . . . . . . . . . . . . . 5-11 5-4. Flexible pavement evaluation curve for CH-47, Types B and C traffic areas . . . . . . . . . . . . . 5-12 5-5. Flexible pavement evaluation curve for OV-1, Type A traffic area . . . . . . . . . . . . . . . . . . . . . 5-13 5-6. Flexible pavement evaluation curve for OV-1, Types B and C traffic areas . . . . . . . . . . . . . . 5-14 5-7. Flexible pavement evaluation curve for C-12, Type A traffic area . . . . . . . . . . . . . . . . . . . . . . 5-15 5-8. Flexible pavement evaluation curve for C-12, Types B and C traffic areas . . . . . . . . . . . . . . 5-16 5-9. Flexible pavement evaluation curve for C-23 (Air Force Group Index 1), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17 5-10. Flexible pavement evaluation curve for C-23 (Air Force Group Index 1), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18 5-11. Flexible pavement evaluation curve for F-15 (Air Force Group Index 2), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19 5-12. Flexible pavement evaluation curve for F-15 (Air Force Group Index 2), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20 5-13. Flexible pavement evaluation curve for F-111 (Air Force Group Index 3), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21 5-14. Flexible pavement evaluation curve for F-111 (Air Force Group Index 3), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22 5-15. Flexible pavement evaluation curve for C-130 (Air Force Group Index 4), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23 5-16. Flexible pavement evaluation curve for C-130 (Air Force Group Index 4), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24 5-17. Flexible pavement evaluation curve for C-9 (Air Force Group Index 5), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25 5-18. Flexible pavement evaluation curve for C-9 (Air Force Group Index 5), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26 5-19. Flexible pavement evaluation curve for T-43 (Air Force Group Index 6), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27 5-20. Flexible pavement evaluation curve for T-43 (Air Force Group Index 6), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28 5-21. Flexible pavement evaluation curve for B-727 (Air Force Group Index 7), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29 5-22. Flexible pavement evaluation curve for B-727 (Air Force Group Index 7), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30 5-23. Flexible pavement evaluation curve for E-3 (Air Force Group Index 8), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31 5-24. Flexible pavement evaluation curve for E-3 (Air Force Group Index 8), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32 5-25. Flexible pavement evaluation curve for C-141 (Air Force Group Index 9), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33 5-26. Flexible pavement evaluation curve for C-141 (Air Force Group Index 9), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-34 5-27. Flexible pavement evaluation curve for C-17 (Air Force Group Index 10), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35 5-28. Flexible pavement evaluation curve for C-17 (Air Force Group Index 10), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-36 5-29. Flexible pavement evaluation curve for C-5 (Air Force Group Index 11), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37 5-30. Flexible pavement evaluation curve for C-5 (Air Force Group Index 11), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-38 5-31. Flexible pavement evaluation curve for KC-10 (Air Force Group Index 12), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-39 v

5-32. Flexible pavement evaluation curve for KC-10 (Air Force Group Index 12), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40

5-33. Flexible pavement evaluation curve for E-4 (Air Force Group Index 13), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-41

5-34. Flexible pavement evaluation curve for E-4 (Air Force Group Index 13), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42

5-35. Flexible pavement evaluation curve for B-52 (Air Force Group Index 14), Type A traffic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-43

5-36. Flexible pavement evaluation curve for B-52 (Air Force Group Index 14), Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-44

5-37. Flexible pavement evaluation curve for F-14, primary traffic area . . . . . . . . . . . . . . . . . . . . . 5-45 5-38. Flexible pavement evaluation curve for F-14, secondary traffic area . . . . . . . . . . . . . . . . . . . 5-46 5-39. Flexible pavement evaluation curve for P-3, primary traffic area . . . . . . . . . . . . . . . . . . . . . . 5-47 5-40. Flexible pavement evaluation curve for P-3, secondary traffic area . . . . . . . . . . . . . . . . . . . . 5-48 5-41. Flexible pavement evaluation curve for C-130, primary traffic area . . . . . . . . . . . . . . . . . . . . 5-49 5-42. Flexible pavement evaluation curve for C-130, secondary traffic area . . . . . . . . . . . . . . . . . . 5-50 5-43. Flexible pavement evaluation curve for C-141, primary traffic area . . . . . . . . . . . . . . . . . . . . 5-51 5-44. Flexible pavement evaluation curve for C-141, secondary traffic area . . . . . . . . . . . . . . . . . . 5-52 5-45. Flexible pavement evaluation curve for C-5, primary traffic area . . . . . . . . . . . . . . . . . . . . . . 5-53 5-46. Flexible pavement evaluation curve for C-5, secondary traffic area . . . . . . . . . . . . . . . . . . . . 5-54 5-47. Comparison of field and laboratory densities and moisture contents . . . . . . . . . . . . . . . . . . . 5-55 6-1. Load factor curves for rigid pavement evaluation, UH-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15 6-2. Load factor curves for rigid pavement evaluation, CH-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 6-3. Load factor curves for rigid pavement evaluations, OV-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 6-4. Load factor curves for rigid pavement evaluation, C-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 6-5. Load factor curves for rigid pavement evaluation, C-23 (Air Force Group

Index 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19 6-6. Load factor curves for rigid pavement evaluation, F-4 (Air Force Group

Index 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20 6-7. Load factor curves for rigid pavement evaluation, F-111 (Air Force Group

Index 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21 6-8. Load factor curves for rigid pavement evaluation, C-130 (Air Force Group

Index 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22 6-9. Load factor curves for rigid pavement evaluation, C-9 (Air Force Group

Index 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23 6-10. Load factor curves for rigid pavement evaluation, T-43 (Air Force Group

Index 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 6-11. Load factor curves for rigid pavement evaluation, B-727 (Air Force Group

Index 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25 6-12. Load factor curves for rigid pavement evaluation, E-3 (Air Force Group

Index 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26 6-13. Load factor curves for rigid pavement evaluation, C-141 (Air Force Group

Index 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27 6-14. Load factor curves for rigid pavement evaluation, C-17 (Air Force Group

Index 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28 6-15. Load factor curves for rigid pavement evaluation, C-5 (Air Force Group

Index 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29 6-16. Load factor curves for rigid pavement evaluation, KC-10 (Air Force Group

Index 12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30 6-17. Load factor curves for rigid pavement evaluation, E-4 (Air Force Group

Index 13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-31 vi

6-18. Load factor curves for rigid pavement evaluation, B-52 (Air Force Group Index 14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32

6-19. Design factor for standard evaluation, UH-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-33 6-20. Design factor for standard evaluation, CH-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34 6-21. Design factors for standard evaluation, OV-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35 6-22. Design factors for standard evaluation, C-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36 6-23. Design factors for standard evaluation, C-23 (Air Force Group Index 1) . . . . . . . . . . . . . . . . 6-37 6-24. Design factors for standard evaluation, F-4 (Air Force Group Index 2) . . . . . . . . . . . . . . . . . . 6-38 6-25 Design factors for standard evaluation, F-111 (Air Force Group Index 3) . . . . . . . . . . . . . . . . 6-39 6-26. Design factors for standard evaluation, C-130 (Air Force Group Index 4) . . . . . . . . . . . . . . . 6-40 6-27. Design factors for standard evaluation, C-9 (Air Force Group Index 5) . . . . . . . . . . . . . . . . . 6-41 6-28. Design factors for standard evaluation, T-43 (Air Force Group Index 6) . . . . . . . . . . . . . . . . . 6-42 6-29. Design factors for standard evaluation, B-727 (Air Force Group Index 7) . . . . . . . . . . . . . . . 6-43 6-30. Design factors for standard evaluation, E-3 (Air Force Group Index 8) . . . . . . . . . . . . . . . . . . 6-44 6-31. Design factors for standard evaluation, C-141 (Air Force Group Index 9) . . . . . . . . . . . . . . . 6-45 6-32. Design factors for standard evaluation, C-17 (Air Force Group Index 10) . . . . . . . . . . . . . . . 6-46 6-33. Design factors for standard evaluation, C-5 (Air Force Group Index 11) . . . . . . . . . . . . . . . . 6-47 6-34. Design factors for standard evaluation, KC-10 (Air Force Group Index 12) . . . . . . . . . . . . . . 6-48 6-35. Design factors for standard evaluation, E-4 (Air Force Group Index 13) . . . . . . . . . . . . . . . . 6-49 6-36. Design factors for standard evaluation, B-52 (Air Force Group Index 14) . . . . . . . . . . . . . . . 6-50 6-37. Design factors for extended life evaluation, UH-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51 6-38. Design factors for extended life evaluation, CH-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52 6-39. Design factors for extended life evaluation, OV-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53 6-40. Design factors for extended life evaluation, C-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-54 6-41. Design factors for extended life evaluation, C-23 (Air Force Group Index 1) . . . . . . . . . . . . . 6-55 6-42. Design factors for extended life evaluation, F-4 (Air Force Group Index 2) . . . . . . . . . . . . . . 6-56 6-43. Design factors for extended life evaluation, F-111 (Air Force Group Index 3) . . . . . . . . . . . . 6-57 6-44. Design factors for extended life evaluation, C-130 (Air Force Group Index 4) . . . . . . . . . . . . 6-58 6-45. Design factors for extended life evaluation, C-9 (Air Force Group Index 5) . . . . . . . . . . . . . . 6-59 6-46. Design factors for extended life evaluation, T-43 (Air Force Group Index 6) . . . . . . . . . . . . . 6-60 6-47. Design factors for extended life evaluation, B-727 (Air Force Group Index 7) . . . . . . . . . . . . 6-61 6-48. Design factors for extended life evaluation, E-3 (Air Force Group Index 8) . . . . . . . . . . . . . . 6-62 6-49. Design factors for extended life evaluation, C-141 (Air Force Group Index 9) . . . . . . . . . . . . 6-63 6-50. Design factors for extended life evaluation, C-17 (Air Force Group Index 10) . . . . . . . . . . . . 6-64 6-51. Design factors for extended life evaluation, C-5 (Air Force Group Index 11) . . . . . . . . . . . . . 6-65 6-52. Design factors for extended life evaluation, KC-10 (Air Force Group Index 12) . . . . . . . . . . . 6-66 6-53. Design factors for extended life evaluation, E-4 (Air Force Group Index 13) . . . . . . . . . . . . . 6-67 6-54. Design factors for extended life evaluation, B-52 (Air Force Group Index 14) . . . . . . . . . . . . 6-68 6-55. Rigid pavement evaluation curves, F-14 (interior load criteria) . . . . . . . . . . . . . . . . . . . . . . . . 6-69 6-56. Rigid pavement evaluation curves, P-3 (interior load criteria) . . . . . . . . . . . . . . . . . . . . . . . . . 6-70 6-57. Rigid pavement evaluation curves, C-130 (interior load criteria) . . . . . . . . . . . . . . . . . . . . . . . 6-71 6-58. Rigid pavement evaluation curves, C-141 (interior load criteria) . . . . . . . . . . . . . . . . . . . . . . . 6-72 6-59. Rigid pavement evaluation curves, C-5 (interior load criteria) . . . . . . . . . . . . . . . . . . . . . . . . . 6-73 6-60. Equivalent thickness of reinforced concrete pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-74 6-61. Factor for determining equivalent thickness of nonrigid overlay, UH-60 . . . . . . . . . . . . . . . . . 6-75 6-62. Factor for determining equivalent thickness of nonrigid overlay, CH-47 . . . . . . . . . . . . . . . . . 6-76 6-63. Factor for determining equivalent thickness of nonrigid overlay, OV-1 . . . . . . . . . . . . . . . . . . 6-77 6-64. Factor for determining equivalent thickness of nonrigid overlay, C-12 . . . . . . . . . . . . . . . . . . 6-78 6-65. Factor for determining equivalent thickness of nonrigid overlay, C-23

(Air Force Group Index 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-79 6-66. Factor for determining equivalent thickness of nonrigid overlay, F-4

(Air Force Group Index 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-80 vii

6-67. Factor for determining equivalent thickness of nonrigid overlay, F-111 (Air Force Group Index 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-81

6-68. Factor for determining equivalent thickness of nonrigid overlay, C-130 (Air Force Group Index 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-82

6-69. Factor for determining equivalent thickness of nonrigid overlay, C-9 (Air Force Group Index 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-83

6-70. Factor for determining equivalent thickness of nonrigid overlay, T-43 (Air Force Group Index 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-84

6-71. Factor for determining equivalent thickness of nonrigid overlay, B-727 (Air Force Group Index 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-85

6-72. Factor for determining equivalent thickness of nonrigid overlay, E-3 (Air Force Group Index 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-86

6-73. Factor for determining equivalent thickness of nonrigid overlay, C-141 (Air Force Group Index 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-87

6-74. Factor for determining equivalent thickness of nonrigid overlay, C-17 (Air Force Group Index 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-88

6-75. Factor for determining equivalent thickness of nonrigid overlay, C-5 (Air Force Group Index 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-89

6-76. Factor for determining equivalent thickness of nonrigid overlay, KC-10 (Air Force Group Index 12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-90

6-77. Factor for determining equivalent thickness of nonrigid overlay, B-707 (Air Force Group Index 13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-91

6-78. Factor for determining equivalent thickness of nonrigid overlay, B-52 (Air Force Group Index 14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-92

6-79. Factor for determining equivalent thickness of nonrigid overlay, F-14 . . . . . . . . . . . . . . . . . . 6-93 6-80. Factor for determining equivalent thickness of nonrigid overlay, P-3 . . . . . . . . . . . . . . . . . . . 6-94 6-81. Fibrous concrete design factors for UH-60, CH-47, OV-1, and C-12, Type A traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-95 6-82. Fibrous concrete design factors for UH-60, CH-47, OV-1, and C-12, Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-96 6-83. Fibrous concrete design factors for Air Force Group Indices 1, 2, and 3, Type A traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-97 6-84. Fibrous concrete design factors for Air Force Group Indices 1, 2, and 3, Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-98 6-85. Fibrous concrete design factors for Air Force Group Indices 4, 5, 6, and 7, Type A traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-99 6-86. Fibrous concrete design factors for Air Force Group Indices 4, 5, 6, and 7, Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-100 6-87. Fibrous concrete design factors for Air Force Group Indices 8 and 9, Type A traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-101 6-88. Fibrous concrete design factors for Air Force Group Indices 8 and 9, Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-102 6-89. Fibrous concrete design factors for Air Force Group Indices 10, 11, 12, 13, and 14, Type A traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-103 6-90. Fibrous concrete design factors for Air Force Group Indices 10, 11, 12, 13, and 14, Types B and C traffic areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-104 7-1. Illustration of thaw-weakening period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15 7-2. Distribution of design air freezing indices in North America . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16 7-3. Distribution of mean air freezing indices in northern Eurasia . . . . . . . . . . . . . . . . . . . . . . . . . 7-17 7-4. Pavement evaluation in frost areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18 7-5. Estimation of combined base for limited subgrade frost penetration . . . . . . . . . . . . . . . . . . . . 7-19 7-6. Determination of FAIR values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-20 viii

8-1. PCN curves for UH-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4 8-2. PCN curves for CH-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5 8-3. PCN curves for OV-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6 8-4. PCN curves for C-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7 8-5. PCN curves for C-130 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8 8-6. PCN curves for C-141 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9 8-7. PCN curves for C-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10 8-8. PCN curves for F-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11 8-9. PCN curves for P-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12 8-10. PCN curves for C-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13 8-11. PCN curves for all Air Force pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

TABLES

Table Title

2-1. Air Force Aircraft Group Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 2-2. Characteristics of Controlling Aircraft Landing Gear Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 2-3. Pass Levels for Air Force Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8 2-4. Loads for Air Force Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19 4-1. WESDEF Default Modulus Values, MPa (psi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 5-1. Equivalency Factors for Army and Air Force Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 5-2. Equivalency Factors for Navy and Marine Corps Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 6-1. Suggested E Values for Stabilized Layers (Use as a guide when values are not available.) . . . 6-4s 7-1. Frost Susceptibility Soil Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 7-2. Values for Different Water Content Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7 7-3. FASSI Values for Various Frost Susceptibility Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8 7-4. Length of End-of-Winter Thaw-Weakened Period for Evaluation Purposes . . . . . . . . . . . . . . . . 7-9

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CHAPTER 1

INTRODUCTION

1. PURPOSE. This document presents criteria for evaluation of the load-carrying capacity of pave-ments used (or to be used) for the support of aircraft. An evaluation is conducted to assess the allowable traffic that a pavement can sustain for given loading conditions or the allowable load for a given amount of traffic without producing unexpected or uncontrolled distress.

2. SCOPE. This document is for use in evaluating Army, Air Force, Navy, and Marine Corps Airfields and Heliports and is applicable to conventional-type pavements. The procedures presented include direct sampling and nondestructive testing techniques. The document also describes computer programs that can be used for pavement evaluation.

3. REFERENCES. Appendix A contains a list of references used in this manual.

4. UNITS OF MEASUREMENT. The unit of measurement in this document is the International System of Units (SI). In some cases, inch-pound (IP) measurements may be the governing critical values because of applicable codes, accepted standards, industry practices, or other considerations. Where the IP measurements govern, the IP value may be shown in parenthesis following a comparative SI value or the IP values may be shown without a corresponding SI value. Chapter 4 contains several regression equations which are not available in SI units, and therefore the units for the equations in that chapter remain as English units.

5. TYPES OF PAVEMENT. The types of pavement considered in this manual are as follows:

a. Flexible Pavement. A pavement with a bituminous surface course and one or more supporting base or subbase courses placed over a prepared subgrade.

b. Plain Concrete Pavement. A single thickness of nonreinforced portland cement concrete resting directly on a prepared subgrade, granular base course, or stabilized layer.

c. Rigid Overlay on Rigid Pavement. A rigid overlay pavement that has been placed on an existing rigid pavement. In the construction of the rigid overlay, a bond-breaking course may or may not have been placed on the existing rigid pavement before the overlay was placed. If the bond-breaking course between the two rigid pavements is 102 millimeters (4 inches) or more in thickness, the entire pavement is considered to be a composite pavement (subparagraph f below).

d. Nonrigid Overlay on Rigid Pavement. A bituminous concrete or combination of bituminous concrete and granular base course that has been placed on an existing rigid pavement.

e. Rigid Overlay on Nonrigid Pavement. A rigid overlay pavement that has been placed on an existing nonrigid pavement.

f. Composite Pavement. A “sandwich pavement” consisting of a rigid overlay placed on an existing pavement that consists of a nonrigid overlay on a rigid pavement. The nonrigid overlay may be bituminous concrete for its full depth or a combination of bituminous concrete and granular base course.

When the thickness of the nonrigid overlay is less than 102 millimeters (4 inches), the entire pavement will be treated as a rigid overlay on rigid pavement and the nonrigid material will be considered to be a bond-breaking course.

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g. Reinforced Concrete Pavement. A concrete pavement that has been reinforced with steel deformed-bar mats or welded-wire fabrics.

h. Fiber Reinforced Concrete. A concrete pavement that has been reinforced with steel fibers.

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CHAPTER 2

EVALUATION CONCEPTS

1. RELATION OF DESIGN TO EVALUATION. The design of a pavement requires selecting materials with the necessary strength and placing them at the proper thickness, density, and depth, so that the pavement will be capable of carrying an anticipated number of passes of a given load. Because of vari-ations in materials and placement conditions, the as-constructed pavement may have strengths and thicknesses of layers greater or less than those required in the design process. Also, with time, usage, and environmental impacts, the elements of a pavement contributing to its strength can be subject to some change. Thus, an evaluation determines the physical properties of a pavement as actually built or in its current condition and establishes therefrom the traffic/load-supporting capacity of the pavement.

2. CONCEPTS. The primary function of a pavement is to spread and distribute the wheel loads placed on it. Each airfield or landing strip has its own natural soil and environmental conditions, and the in situ soils must ultimately sustain the stresses resulting from loads applied to the pavement. Since the strengths of native soils can vary widely from site to site, the ability to support loads also varies widely.

Except in special cases, aircraft tire loads cannot be satisfactorily sustained directly on the native soils.

a. Pavement Structure. Pavement design and evaluation are concerned with determining the capability of the pavement structure to reduce the load intensity to a magnitude the airfield site soils can sustain. The larger the load on the surface or the higher the contact pressure, the stronger the pavement structure must be to distribute load and reduce load intensity (pressure or stress) to that which the native soil can accept. Layered flexible pavements distribute load by broadening the effective area supporting the load, from the tire contact area on the surface to a wider area on the base, to a still wider area on the subbase, and so on. Each layer must be of a quality to sustain the load intensity or stress it must accept, and each must be thick enough to broaden or distribute the load and reduce intensity to that which its supporting layer can sustain. Rigid pavements are stiffer and have a “beam action” or flexural capability that spreads or distributes load more widely, so these pavements can be much thinner than flexible pave-ments. However, thickness, flexural strength, and other quality aspects must be assessed during the evaluation process.

b. Loadings. Early aircraft were primarily supported on two main landing gear wheels, referred to as “single” wheels. With the large increases in aircraft gross weights, landing gears have changed to twin (2 per strut) wheel loadings, to twin-tandem (4-wheel) loadings, and to more complex (16 and 24 main gear wheels, extra “belly” gear) wheel support systems. The two main wheels of single-wheel aircraft are generally spaced far enough apart that there is no significant overlap of the distributed loads for even very thick pavement structures protecting weak subgrades. For twin wheels, however, and closely spaced tandem wheels or complex wheel groups, the patterns of distributed surface loadings at and near the bottom of pavement structures overlap so that the intensities (pressures or stresses) combine between adjacent wheels. This combining effect of load intensities is greater as the adjacent wheels become closer.

c. Tire Pressure. The intensity of stress at a given point in a flexible pavement is affected by the tire contact pressure, which, for large aircraft tires, is roughly equivalent to the inflation pressures. The major difference in stress intensities caused by variation in tire pressure occurs near the surface; conse-quently, the pavement surfacing and upper base-course layers are most seriously affected by high tire pressures.

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d. Load Repetitions.

(1) Repetitions of load or aircraft passes is an aspect of structural capacity. A pavement cap-able of sustaining a certain aircraft loading on a regular repeating basis for some design life of the facility (commonly 10 years for Navy and Marine Corps Airfields) can sustain repeated…