Diseño de Pavimentos ARMY USA

ARMY TM 5-822-5AIR FORCE AFM 88-7, CHAP. 1

PAVEMENT DESIGN FOR ROADS,STREETS, WALKS, ANDOPEN STORAGE AREAS

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION IS UNLIMITED

DEPARTMENTS OF THE ARMY AND THE AIR FORCE

JUNE 1992

REPRODUCTION AUTHORIZATION/RESTRICTIONS

This manual has been prepared by or for the Government and is publicproperty and not subject to copyright.

Reprints or republications of this manual should include a credit substan-tially as follows: Joint Departments of the Army and Air Force, TM 5-822-5/AFM 88-7, Chapter 1, Pavement Design for Roads, Streets, Walks,and Open Storage Areas, 12 June 1992.

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*TM 5-822-5*AFM 88-7, Chap. 1

TECHNICAL MANUAL HEADQUARTERSNo. 5-822-5 DEPARTMENT OF THE ARMYAIR FORCE MANUAL AND THE AIR FORCENo. 88-7, CHAPTER 1 WASHINGTON, DC, 12 June 1992

PAVEMENT DESIGN FOR ROADS, STREET, WALKS, AND OPENSTORAGE AREAS

Paragraph PageCHAPTER 1. INTRODUCTION

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1-1Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1-1References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 1-1Selection of Pavement Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 1-1Basis of Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 1-1Computer Aided Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6 1-1

CHAPTER 2. PRELIMINARY INVESTIGATIONSGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 2-1Investigations of Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2-1Soil Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 2-1Borrow Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 2-1

CHAPTER 3. VEHICULAR TRAFFICEffect on Pavement Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3-1Traffic Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3-1

CHAPTER 4. FLEXIBLE PAVEMENT SUBGRADESFactors To Be Considered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4-1Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 4-1Compaction Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 4-1Selection of Design CBR Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 4-2

CHAPTER 5. FLEXIBLE PAVEMENT SELECT MATERIALS AND SUBBASE COURSESGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 5-1Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 5-1Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 5-4Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 5-2Selection of Design CBR Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 5-2

CHAPTER 6. FLEXIBLE PAVEMENT BASE COURSESMaterials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 6-1Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 6-1Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 6-1Selection of Design CBR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 6-1Minimum Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 6-1

CHAPTER 7. BITUMINOUS PAVEMENTGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 7-1Criteria for Bituminous Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2 7-1

CHAPTER 8. FLEXIBLE PAVEMENT DESIGNGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 8-1Design Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2 8-1Design Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3 8-1Thickness Criteria-Conventional Flexible Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4 8-1Example Thickness Design-Conventional Flexible Pavements . . . . . . . . . . . . . . . . . . . . . . . 8-5 8-2Thickness Criteria-Stabilized Soil Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6 8-3Example Thickness Design-Stabilized Soil Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7 8-4Shoulders and Similar Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8 8-4Bituminous Sidewalks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9 8-5Bituminous Driveways. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10 8-5

This publication with special software (Appendix E) has a value of less than $100.00 per copy, and does not require accountabilityunder the provisions of AR 735-17 and AR 710-2-1.

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION IS UNLIMITED_________

*This manual supersedes TM 5-822-5/AFM 88-7, Chap 3, dated 1 October 1980 and TM 5-822-6/AFM 88-7, Chap 1, dated 1 April 1977.

*TM 5-822-5

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Paragraph PageCurbs and Gutters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11 8-6Flexible Overlay Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12 8-6

CHAPTER 9. RIGID PAVEMENT SUBGRADESSoil Classification and Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 9-1Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2 9-1Treatment of Unsuitable Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3 9-1Determination of Modulus of Subgrade Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4 9-2

CHAPTER 10. RIGID PAVEMENT BASE COURSESGeneral Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 10-1Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2 10-1Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 10-1Frost Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4 104

CHAPTER 11. CONCRETE PAVEMENTMix Proportioning and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1 11-1Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 11-1Special Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 11-1

CHAPTER 12. PLAIN CONCRETE PAVEMENT DESIGNGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1 12-1Roller-Compacted Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 12-1Design Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3 12-1Design Procedure for Stabilized Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4 12-3Design Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-5 12-4Concrete Sidewalks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-6 12-4Concrete Driveways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7 12-5Curbs, Gutters, and Shoulders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8 12-5

CHAPTER 13. REINFORCED CONCRETE PAVEMENTSApplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1 13-1Design Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 13-3Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3 13-5Reinforcing Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4 13-5Design Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5 13-5Design Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-6 13-6

CHAPTER 14. PAVEMENT OVERLAYSGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1 14-1Definitions and Symbols for Overlay Pavement Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2 14-1Preparation of Existing Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 14-1Condition of Existing Rigid Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4 14-2Rigid Overlay of Existing Rigid Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5 14-2Rigid Overlay of Existing Flexible or Composite Pavements . . . . . . . . . . . . . . . . . . . . . . . . . 14-6 14-4Flexible Overlay of Flexible Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7 14-4Flexible Overlay of Rigid Base Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-8 14-4Use of Geotextiles to Retard Reflective Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-9 14-7Overlays in Frost Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-10 14-8Overlay Design Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-11 14-8

CHAPTER 15. JOINTS FOR PLAIN CONCRETEDesign Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1 15-1Joint Types and Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-2 15-1Dowels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3 15-17Special Provisions for Slipform Paving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-4 15-17Joint Sealing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5 15-17Special Joints and Junctures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6 15-17

CHAPTER 16. JOINTS FOR REINFORCED CONCRETERequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1 16-1Joint Sealing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2 16-8

CHAPTER 17. ROLLER-COMPACTED CONCRETE PAVEMENTSIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1 17-1Load Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2 17-1Thickness Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3 17-1Multilift Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-4 17-1Joint Types for RCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-5 17-2

CHAPTER 18. SEASONAL FROST CONDITIONSGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1 18-1Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2 18-2Frost-Susceptibility Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3 18-4

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Paragraph PageAlternative Methods of Thickness Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-4 18-6Selection of Design Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-5 18-6Limited Subgrade Frost Penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-6 18-6Reduced Subgrade Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-7 18-12Use of State Highway Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-8 18-14Free-Draining Material Directly Beneath Bound Base or Surfacing Layer . . . . . . . . . . . . . . 18-9 18-14Other Granular Unbound Base Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-10 18-15Use of Fl and F2 Soils for Base Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-11 18-15Filter or Drainage Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-12 18-15Stabilizers and Stabilized Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-13 18-15Stabilization with Lime and with LCF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-14 18-16Stabilization with Portland Cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-15 18-16Stabilization with Bitumen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-16 18-16Subgrade Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-17 18-16Other Measures to Reduce Heave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-18 18-18Pavement Cracking Associated with Frost Heave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-19 18-18Control of Subgrade and Base Course Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-20 18-18Base Course Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-21 18-19Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-22 18-19Use of Insulation Materials in Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-23 18-19Design Example-Heavily Trafficked Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-24 18-19

APPENDIX A. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1APPENDIX B. DETERMINATION OF FLEXURAL STRENGTH AND MODULUS OF ELASTICITY OF

BITUMINOUS CONCRETE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1APPENDIX C. METHOD OF TEST FOR PERFORMED POLYCHLOROPRENE ELASTOMERIC JOINT

SEAL JET-FUEL-RESISTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1APPENDIX D. USE OF INSULATION MATERIALS IN PAVEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1APPENDIX E. COMPUTER AIDED DESIGN FOR FLEXIBLE ROAD PAVEMENTS/RIGID ROAD PAVEMENTS . E-1

List of Figures

Figure No. Title Page8-1. Flexible Pavement Design Curve for Roads and Streets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-28-2. Equivalency Factors for Soils Stabilized with Cement, Lime or Cement and Lime Mixed with Flyash . . . . . . . . . . . 8-49-1. Effect of Base-Course Thickness on Modulus of Soil Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

12-1. Design Curves for Plain Concrete Roads and Streets, and RCCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-212-2. Design Curve for Plain Concrete Parking and Open Storage Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3134. Typical Layout of Joints at Intersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-213-2. Reinforced Rigid Pavement Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-413-3. Design Details of Reinforced Rigid Pavement with Two Traffic Lanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-613-4. Design Details of Reinforced Rigid Pavement with Traffic and Parking Lanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-813-5. Design Details of Reinforced Rigid Pavement with Integral Curb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-913-6. Typical Layout of Joints at the Intersection of Reinforced Rigid Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1114-1. Factor for Projecting Cracking in a Flexible Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-614-2. Location Guide for the Use of Geotextiles in Retarding Reflective Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-615-1. Design Details for Plain Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-215-2. Joint Layout for Vehicular Parking Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-415-3. Contraction Joints for Plain Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-515-4. Construction Joints for Plain Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-615-5. Expansion Joints for Plain Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1015-6. Thickened-Edge Slip Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1115-7. Joint Sealant Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1216-1. Contraction Joints for Reinforced Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-216-2. Construction Joints for Reinforced Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-316-3. Expansion Joints for Reinforced Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-718-1. Determination of Freezing Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-418-2. Distribution of Design Freezing Index for North America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-818-3. Frost Penetration Beneath Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-918-4. Design Depth of Nonfrost-Susceptible Base for Limited Subgrade Frost Penetration . . . . . . . . . . . . . . . . . . . . . . . . . 18-1218-5. Frost-Area Index of Reaction for Design of Rigid Roads, Streets, and Open Storage Areas . . . . . . . . . . . . . . . . . . . . 18-1418-6. Tapered Transition Used Where Embankment Material Differs from Natural Subgrade in Cut . . . . . . . . . . . . . . . . 18-18D-1. Equivalent Sinusoidal Surface Temperature Amplitude A and Initial Temperature Difference V . . . . . . . . . . . . . . D-2oD-2. Thickness of Extruded Polystyrene Insulation to Prevent Subgrade Freezing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-3D-3. Effect of Thickness of Insulation and Base on Frost Penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-4

*TM 5-822-5

iv

List of Tables

Table No. Title Page3-1. Pavement Design Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24-1. Depth of Compaction for Select Materials and Subgrades (CBR < 20). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15-1. Maximum Permissible Design Values for Subbases and Select Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16-1. Minimum Thickness of Pavement and Base Course. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28-1. Equivalency Factors for Bituminous Stabilized Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-39-1. Modulus of Soil Reaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-2

15-1. Maximum Allowable Spacing of Transverse Contraction Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-1515-2. Dowel Size and Spacing for Construction, Contraction, and Expansion Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1518-1. Modes of Distress in Pavements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-218-2. Frost Design Soil Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18-518-3. Frost-Area Soil Support Indexes for Subgrade Soils for Flexible Pavement Design. . . . . . . . . . . . . . . . . . . . . . . . . . 18-13

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CHAPTER 1

INTRODUCTION

1-1. Purpose. (5)Modulus of rupture (flexural strength) forThis manual provides criteria for the design ofpavements for roads, streets, walks, and open stor-age areas at U.S. Army and Air Force installations.

1-2. Scope.This manual provides criteria for plain concrete,reinforced concrete, flexible pavements, and designfor seasonal frost conditions. These criteria includesubgrade and base requirements, thickness designs,and compaction requirements, criteria for stabilizedlayers, concrete pavement joint details, andoverlays.

1-3. References.Appendix A contains a list of references used in thismanual.

1-4. Selection of Pavement Type.Rigid pavements or composite pavements with arigid overlay are required for the following areas.

a. Vehicle Maintenance Areas.b. Pavements for All Vehicles with Nonpneuma-

tic Tires.c. Open Storage Areas with Materials Having

Nonpneumatic Loadings in Excess of 200 psi.d. Covered Storage Areas.e. Organizational Vehicle Parking Areas.f. Pavements Supporting Tracked Vehicles.g. Vehicle Wash Racks.h. Vehicle Fueling Pads.

Except for architectural or special operational re-quirements, all other pavements will be designedbased upon life-cycle cost analysis.

1-5. Basis of Design.a. Design Variables. The prime factor influenc-

ing the structural design of a pavement is the load-carrying capacity required. The thickness ofpavement necessary to provide the desired load-carrying capacity is a function of the following fiveprincipal variables-

(1)Vehicle wheel load or axle load.(2)Configuration of vehicle wheels or tracks.(3)Volume of traffic during the design life of

pavement.(4)Soil strength.

concrete pavements.b. Rigid Pavements. The rigid pavement design

procedure presented herein is based upon the criti-cal tensile stresses produced within the slab by thevehicle loading. Correlation between theory, small-scale model studies, and full-scale accelerated traf-fic tests have shown that maximum tensile stressesin the pavement occur when the vehicle wheels aretangent to a free or unsupported edge of thepavement. Stresses for the condition of the vehiclewheels tangent to a longitudinal or trans-verse jointare less severe because of the use of load-transferdevices in these joints to transfer a portion of theload to the adjacent slab. Other stresses, because oftheir cyclic nature, will at times be additive to thevehicle load stresses and include restraint stressesresulting from thermal expansion and contraction ofthe pavement and warping stresses resulting frommoisture and temperature gradients within thepavement. Provision for those stresses not inducedby wheel loads is included in design factorsdeveloped empirically from full-scale acceleratedtraffic tests and from the observed performance ofpavements under actual service conditions.

c. Flexible Pavement. The design procedureused by the Corps of Engineers and the Air Forceto design flexible pavements is generally referred toas the California Bearing Ratio (CBR) design pro-cedure. This procedure requires that each layer bethick enough to distribute the stresses induced bytraffic so that when they reach the underlying layerthey will not overstress and produce excessiveshear deformation in the underlying layer. Eachlayer must also be compacted adequately so thattraffic does not produce an intolerable amount ofadded compaction. Use ASTM D 1557 compactioneffort procedures to design against consolidationunder traffic.

1-6. Computer Aided Design.In addition to the design procedures presentedherein, computer programs are available for deter-mining pavement thickness and compaction re-quirements for roads, streets, and open storageareas. These programs are contained on the floppydisk appendix E located in pocket to cover 3.

a. Development. Computer programs have been

TM 5-822-5/AFM 88-7, Chap. 1

1-2

developed to aid in the design of pavements for identical to the data required by the design manual,roads, streets, and open storage areas. The pro- and the results obtained from the program shouldgrams were developed on an IBM PC-AT using be close to the results obtained from the designFORTRAN 77 as the development language with curves. Because the computer program recalculatesMicrosoft's FORTRAN Compiler (version 3.2) and data and approximates certain empirical data, thereMS-DOS (version 3.1) as the operating system. may be some minor differences in results from theNormally, the programs will be furnished as a program and from the manual. If significantcompiled program which can be executed from difference are obtained contact HQUSACEfloppy diskettes or hard drives. Thus far all the (CEMP-ET).programs have been run on IBM PC-AT or IBM c. Program names. The flexible pavement roadcompatible microcomputers containing a minimumdesign program is FRD 904, and the rigid pave-of 512K RAM. ment design program is RRD 805. The numbers in

b. Use of programs. In development of the com- the name refer to the date of the program. The firstputer programs, an effort was made to provide a digit is the year of the revision. The last two digitsuser friendly program requiring no external in- of the program name is the month of the revision.structions for use of the programs. Aside from in-Thus, the program FRD 904 is the flexible roadstructions for initiating execution, which is standard design program that was revised in April 1989.for any executable program, the user is lead Care should be taken that the latest version of thethrough the design procedure by a series of ques- computer programs is being used. If there is doubttions and informational screens. The input data re-concerning a program, contact HQUSACEquired for pavement design by the program are (CEMP-ET).

TM 5-822-5/AFM 88-7, Chap. 1

2-1

CHAPTER 2

PRELIMINARY INVESTIGATIONS

2-1. General. conditions in ditches, and cuts and tests ofThe subgrade provides a foundation for supportingthe pavement structure. As a result, the requiredpavement thickness and the performance obtainedfrom the pavement during its design life will dependlargely upon the strength and uniformity of thesubgrade. Therefore, insofar as is economicallyfeasible, a thorough investigation of the sub-gradeshould be made so that the design and constructionwill ensure uniformity of support for the pavementstructure and realization of the maximum strengthpotential for the particular sub-grade soil type. Theimportance of uniformity of soil and moistureconditions under the pavement cannot beoveremphasized with respect to frost action.

2-2. Investigations of Site.Characteristics of subgrade soils and peculiar fea-tures of the site must be known to predict pave-ment performance. Investigations should determinethe general suitability of the subgrade soils basedon classification of the soil, moisture-densityrelation, degree to which the soil can be compact-ed, expansion characteristics, susceptibility topumping, and susceptibility to detrimental frostaction. Such factors as groundwater, surface infil-tration, soil capillarity, topography, rainfall, anddrainage conditions also will affect the future sup-port rendered by the subgrade by increasing itsmoisture content and thereby reducing itsstrength. Past performance of existing pavementsover a minimum of 5 years on similar local sub-rades should be used to confirm the proposeddesign criteria. All soils should be classified ac-cording to the Unified Soil Classification Systems(USCS) in ASTM D 2487.

2-3. Soil Conditions.a. General survey of subgrade conditions.

Sources of data should include the landforms, soil

representative soils in the site. The survey shouldbe augmented with existing soil and geologicalmaps. Both natural and subsurface drainage of thesubgrade must be considered.

b. Preliminary subsurface explorations. Prelimi-nary subsurface explorations should be made at in-tervals selected to test each type of soil and topog-raphy identified in the general survey. Additionalsubsurface explorations should be made in thoseareas where the preliminary investigation indicatesunusual or potentially troublesome subgradeconditions. In determining subgrade conditions,borings will be carried to the depth of frost pene-tration, but no less than 6 feet below the finishedgrade. In the design of some high fills, it may benecessary to consider settlement caused by theweight of the fill. The depth requirements statedabove will usually result in the subsurface explora-tions reaching below the depth of maximum frostpenetration. If this is not the case, they should beextended to the maximum depth of frost penetra-tion below the design grade as determined fromchapter 10.

c. Soil. Soil samples from the preliminary bor-ings should be classified and the data used to pre-pare soil profiles and to select representative soilsfor further testing. Measurements should includemoisture contents which indicate soft layers in thesoil.

2-4. Borrow Areas.Where material is to be borrowed from adjacentareas, subsurface explorations should be made inthese areas and carried 2 to 4 feet below the an-ticipated depth of borrow. Samples from the explo-rations should be classified and tested for moisturecontent and compactions characteristics.

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3-1

CHAPTER 3

VEHICULAR TRAFFIC

3-1. Effect on Pavement Design. weights and the maximum allowable weights. ForPavement thickness must be designed to withstandthe anticipated traffic, categorized by type andweight of vehicles, and measured by average dailyvolume (ADV) of each type for the design life ofthe pavement. For most pavements, the magnitudeof the axle load is of greater importance than thegross weight of pneumatic-tired vehicles becauseaxle spacings are generally so large that there islittle interaction between the wheel loads of oneaxle and the wheel loads of the other axles. Thus,for the case of pneumatic-tired vehicles havingequal axle loads, the increased severity of loadingimposed by conventional four- or five-axle trucksas compared with that imposed by two- or three-axle trucks is largely a fatigue effect resulting froman increased number of load repetitions per vehicleoperation. For forklift trucks where the loading isconcentrated largely on a single axle and fortracked vehicles where the loading is evenly dividedbetween the two tracks, the severity of the vehicleloading is a function of the gross weight of thevehicle and the frequency of loading. Relationsbetween load repetition and required rigidpavement thickness developed from acceleratedtraffic tests of full-scale pavements have shownthat, for any given vehicle, increasing the grossweight by as little as 10 percent can be equivalentto increasing the volume of traffic by as much as300 to 400 percent. On this basis, the magnitude ofthe vehicle loading must be considered as a moresignificant factor in the design of pavements thanthe number of load repetitions.

3-2. Traffic Evaluation.Procedures for the evaluation of traffic and selec-tion of design index are as follows.

a. Pneumatic-tired vehicles. To aid inevaluating vehicular traffic for the purpose ofpavement design, pneumatic-tired vehicles havebeen divided into the following three groups

Group 1. Passenger cars, panel trucks, andpickup trucks

Group 2. Two-axle trucksGroup 3. Three-, four-, and five-axle trucks

The design weights for various pneumatic-tired ve-hicles have been based on average weights, as de-termined from Federal Highway Administrationtraffic surveys made on public highways, plus one-fourth of the difference between these average

group 2 and group 3 vehicles, maximum allowableweights are based on single-axle and tandem-axleloadings not exceeding 18,000 and 32,000 pounds,respectively. Since traffic rarely will be composedof vehicles from a single group, pneumatic-tiredvehicular traffic has been classified into five generalcategories based on the distribution of vehiclesfrom each of the three groups listed above. Thesetraffic categories are defined as follows

Category I. Traffic composed primarily of pas-senger cars, panel and pickup trucks (group 1vehicles), but containing not more than 1 percenttwo-axle trucks (group 2 vehicles).Category II. Traffic composed primarily of pas-senger cars, panel and pickup trucks (group 1vehicles), but may contain as much as 10 percenttwo-axle trucks (group 2 vehicles). No truckshaving three or more axles (group 3 vehicles) arepermitted in this category.Category III. Traffic containing as much as 15percent trucks, but with not more than 1 percentof the total traffic composed of trucks havingthree or more axles (group 3 vehicles).Category IV. Traffic containing as much as 25percent trucks, but with not more than 10 percentof the total traffic composed of trucks havingthree or more axles group 3 vehicles).Category IVA. Traffic containing more than 25percent trucks.b. Tracked vehicles and forklift trucks. Tracked

vehicles having gross weights not exceeding 15,000pounds and forklift trucks having gross weights notexceeding 6,000 pounds may be treated as two-axle trucks (group 2 vehicles) and substituted fortrucks of this type in the traffic categories definedabove on a one-for-one basis. Tracked vehicleshaving gross weights exceeding 15,000 pounds butnot 40,000 pounds and forklift trucks having grossweights exceeding 6,000 pounds but not 10,000pounds may be treated as group 3 vehicles andsubstituted for trucks having three or more axles inthe appropriate traffic categories on a on-for-onebasis. Traffic composed of tracked vehicles ex-ceeding 40,000 pounds gross weight and forklifttrucks exceeding 10,000 pounds gross weight hasbeen divided into the following three categories

TM 5-822-5/AFM 88-7, Chap. 1

3-2

c. Selection of design index. The design of anticipated for a road in flat terrain. First, the roadpavements for Army and Air Force roads, streets, class is determined from TM 5-822-2/AFM 88-7,and similar areas is based on a design index, Chap. 5 to be a class D road. Second, the group 2which represents the combined effect of the loads vehicles are 100/2,000 or 5 percent of the total ofdefined by the traffic categories just described andgroups 1 and 2, making this category II traffic.the traffic volumes associated with each of the Therefore, the appropriate design index from tablelettered classifications of roads or streets. This 3-1 is 2.index extends from one through ten with an

increase in numerical value indicative of an increasein pavement design requirements. Table 3-1 givesthe appropriate design index for combinations ofthe eight traffic categories based on distribution oftraffic, vehicle type, and the six-letter classificationsbased on the volume of traffic. For example,suppose an average daily traffic (ADT) of 2,000vehicles composed primarily of passenger cars,panel trucks, and pickup trucks (group 1), butincluding 100 two-axle trucks (group 2) is

(1) Tracked vehicles and forklift trucks. tired vehicles, forklifts, and tracked vehicles are toProvision is made whereby the designer may be considered, the proper letter classification of thedetermine pavement design requirements for road or street is determined from TM 5-822-2/tracked vehicles or forklifts in combination with AFM 88-7, Chapter 5 according to the total volumetraffic by pneumatic-tired vehicles or for traffic by of traffic from all types of vehicles. In table 3-1 thetracked vehicles or forklifts only. Where pneumatic-traffic for categories V, VI, and VII has been

TM 5-822-5/AFM 88-7, Chap. 1

3-3

divided further into various levels of frequency. If should be determined from the column for class Ethe tracked vehicle or forklift traffic is composed ofroads or streets, again taking into account thevehicles from more than a single traffic category, itrelative traffic frequencies where there are vehicleswill be necessary for the designer to determine thefrom more than a single traffic category.anticipated frequency of traffic in each category in (2)Special-Purpose Vehicles. Information re-order to determine the appropriate design index. garding pavement design requirements for specialFor example, 40 vehicles per day of category VI purpose vehicles producing loadings significantlytraffic require a greater pavement design index thangreater than those defined in this manual will bedoes one vehicle per day of category VII traffic. requested from Headquarters, US Army Corps ofThus, the designer cannot rely on maximum gross Engineers (CEMP-ET), or the appropriate Airweight alone to determine pavement design index Force Major Command.values. For vehicular parking areas, the design index

TM 5-822-5/AFM 88-7, Chap. 1

4-1

CHAPTER 4

FLEXIBLE PAVEMENT SUBGRADES

4-1. Factors To Be Considered. 4-2. Compaction.The information obtained from the explorations and The natural density of the subgrade must be suffi-tests previously described should be adequate to cient to resist densification under traffic or theenable full consideration of all factors affecting thesubgrade must be compacted during constructionsuitability of the subgrade and subsoil. The primaryto a depth where the natural density will resistfactors are as follows: densification under traffic. Table 4-1 shows the

a. The general characteristics of the subgrade depth, measured from the pavement surface, atsoils such as soil classification, limits, etc. which a given percent compaction is required to

b. Depth to bed rock. prevent densification under traffic. Subgrades inc. Depth to water table (including perched water cuts must have natural densities equal to or greater

table). than the values shown in table 4-1. Where such isd. The compaction that can be attained in the not the case, the subgrade must be compacted from

subgrade and the adequacy of the existing density the surface to meet the tabulated densities, or bein the layers below the zone of compaction require- removed and replaced in which case thements. requirements for fills apply, or be covered with

e. The CBR that the compacted subgrade and sufficient select material, subbase, and base so thatuncompacted subgrade will have under local envi-the uncompacted subgrade is at a depth where theronmental conditions. in-place densities are satisfactory. In fill areas,

f. The presence of weak of soft layers in the cohesionless soils will be placed at no less than 95sub- soil. percent of ASTM D 1557 maximum density nor

g. Susceptibility to detrimental frost action.cohesive fills at less than 90 percent 0 ASTM D1557 maximum density.

4-3. Compaction Example. 12 inches below the pavement surface. Below thisAn example illustrating the application of sub-gradecompaction requirements is as follows:

a. Cohesion less subgrade. Assume a cleancohesionless sand and a design CBR of 18, with anatural in-place density of 90 percent of maximumdensity to beyond the depth of exploration of 6 feet.From table 4-1 for a design index of 5, it is foundthat 100 percent density must extend to a depth of

depth, fill sections must be compacted to 95 percentmaximum density throughout, and cut sections to95 percent of maximum density to a depth of 22inches below the pavement surface. The designermust decide from previous experience or from test-section data whether or not these percentages ofcompaction in cut sections can be obtained from thetop of the subgrade. If they cannot, a part of thesubgrade must be removed, the underlying layer

TM 5-822-5/AFM 88-7, Chap. 1

4-2

compacted, and the material replaced, or the should be 85 percent of maximum density tothickness of select material or subbase must be so conform to fill requirements.increased that the densities in the uncompactedsubgrade will be adequate. 4-4. Selection of Design CBR Values.

b. Cohesive subgrade. Assume a lean clay, adesign CBR of 7, and a natural in-place density of83 percent of maximum density extending below thedepth of exploration of 6 feet. Compaction of thesubgrade from the surface would be impracticablewith ordinary equipment beyond the 6- to 8-inchdepth that could be processed; therefore, theminimum depth of cut would be limited by the in-place density. From table 4-1 for a design index of5, it is found that the 83 percent in-place naturaldensity would be satisfactory below depths of about25 inches from the pavement surface. From CBRdesign curves (explained subsequently), the top ofthe subgrade will be 14.5 inches below thepavement surface; therefore, a zone 10.5 inchesthick below the top of the subgrade requires treat-ment. The bottom 6 to 8 inches of this can be proc-essed in place; so about 4 inches of material must beremoved and replaced. Compaction to 95 percent ofmaximum density is required for all cohesivematerial that lies within 12 inches of the pavementsurface. Since the subgrade does not fall within thiszone compaction requirements in the replacedmaterial should be 90 percent to conform to fillrequirements, and the layer processed in place

Flexible pavements may be designed using the lab-oratory soaked CBR, the field in-place CBR, or theCBR from undisturbed samples as described inMIL-STD-621A, Method 101. For the design offlexible pavements in areas where no previous ex-perience regarding pavement performance is avail-able, the laboratory soaked CBR is normally used.Where an existing pavement is available at the sitethat has a subgrade constructed to the samestandards as the job being designed, in-place testsor tests on undisturbed samples may be used in se-lecting the design CBR value. In-place tests areused when the subgrade material is at the maximumwater content expected in the prototype. Contrarily,tests on undisturbed samples are used where thematerial is not at the maximum water content andthus soaking is required. Sampling involvesconsiderably more work than in-place tests; also,"undisturbed" samples tend to be slightly disturbed;therefore, in-place tests should be used wherepossible. Guides for determining when in-place testscan be used are given in details of the CBR test inMIL-STD-621A, Test Method 101.

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5-1

CHAPTER 5

FLEXIBLE PAVEMENT SELECT MATERIALS AND SUBBASECOURSES

5-1. General.It is common practice in pavement design to uselocally available or other readily available materialsbetween the subgrade and base course for econ-omy. These layers are designated in this manual asselect materials or subbases. Those with designCBR values equal to or less than 20 are designatedselect materials, and those with CBR values above20 are designated subbases. Minimum thicknessesof pavement and base have been established toeliminate the need for subbases with design CBRvalues above 50. Where the design CBR value ofthe subgrade without processing is in the range of20 to 50, select materials and subbases may not beneeded. However, the subgrade cannot be assigneddesign CBR values of 20 or higher unless it meetsthe gradation and plasticity requirements for sub-bases.

5-2. Materials.The investigations described in chapter 2 will beused to determine the location and characteristicsof suitable soils for select material and subbaseconstruction.

a. Select materials. Select materials will normal-ly be locally available coarse-grained soils (prefix Gor S), although fine-grained soils in the ML and CLgroups may be used in certain cases. Limerock,coral, shell, ashes, cinders, caliche, disintegratedgranite, and other such materials should be consid-ered when they are economical. Recommendedplasticity requirements are listed in table 5-1. Amaximum aggregate size of 3 inches is suggested toaid in meeting grading requirements.

b. Subbase materials. Subbase materials may in this way is not satisfactory. Material stabilizedconsist of naturally occurring coarse-grained soils with commercial additives may be economical as aor blended and processed soils. Materials such as subbase. Portland cement, lime, flyash, or bitumenlimerock, coral, shell, ashes, cinders, caliche, and and combinations thereof are commonly employeddisintegrated granite may be used as subbases whenfor this purpose. Also, it may be possible tothey meet the requirements described in table 54. decrease the plasticity of some materials by use ofThe existing subgrade may meet the requirements lime or portland cement in sufficient amounts tofor a subbase course or it may be possible to treat make them suitable as subbases.the existing subgrade to produce a subbase.However, admixing native or processed materials 5-3. Compaction.will be done only when the unmixed subgrade meetsthe liquid limit and plasticity index requirements forsubbases. It has been found that "cutting" plasticity

These materials can be processed and compactedwith normal procedures. Compaction of subbaseswill be 100 percent of ASTM D 1557 density

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5-2

except where it is known that a higher density can struction is available, CBR tests may be made inbe obtained practically, in which case the higher place on material when it has attained its maximumdensity should be required. Compaction of select expected water content or on undisturbed soakedmaterials will be as shown in table 4-1 except that samples. The procedures for selecting CBR designin no case will cohesionless fill be placed at less values described for subgrades apply to selectthan 95 percent or cohesive fill at less than 90 materials and subbases. CBR tests on gravellypercent. materials in the laboratory tend to give CBR values

5-4. Drainage. difference is attributed to the processing necessarySubbase drainage is an important aspect of designand should be accomplished in accordance with TM5-820-2/AFM 88-5, Chap. 2.

5-5. Selection of Design CBR Values.The select material or subbase will generally beuniform, and the problem of selecting a limitingcondition, as described for the subgrade, does notordinarily exist. Tests are usually made on remoldedsamples; however, where existing similar con-

higher than those obtained in the field. The

to test the sample in the 6-inch mold, and to theconfining effect of the mold. Therefore, the CBRtest is supplemented by gradation and Atterberglimits requirements for subbases, as shown in table5-1. Suggested limits for select materials are alsoindicated. In addition to these requirements, thematerial must also show in the laboratory tests aCBR equal to or higher than the CBR assigned tothe material for design purposes.

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6-1

CHAPTER 6

FLEXIBLE PAVEMENT BASE COURSES

6-1. Materials. High-quality materials must be mold, the laboratory CBR test will not be used inused in base courses of flexible pavements. These determining CBR values of base courses. In-stead,high-quality materials provide resistance to the high selected CBR ratings will be assigned as shown instresses that occur near the pavement surface. the following tabulation. These ratings have beenGuide specifications for graded crushed aggregate,based on service behavior records and, wherelimerock, and stabilized aggregate may be used pertinent, on in-place tests made on materials thatwithout qualification for design of roads, streets, had been subjected to traffic. It is imperative thatand parking areas. Guide specifications for dry- and the materials conform to the quality requirementswater-bound macadam base courses may be used given in the guide specifications so that they willfor design of pavements only when the cost of thedevelop the needed strengths.dry- or water-bound macadam base does notexceed the cost of stabilized-aggregate base course,and the ability of probable bidders to constructpavements with dry- or water-bound macadam baseto the required surface smoothness and gradetolerances has been proved by experience in thearea.

6-2. Compaction. Base courses placed in flexiblepavements should be compacted to the maximumdensity practicable, generally in excess of 100percent of ASTM D 1557 maximum density butnever less than 100 percent of ASTM D 1557maximum density. 6-5. Minimum Thickness. The minimum allow-

6-3. Drainage. Drainage design for base coursesshown in table 6-1, except that in no case will theshould be accomplished in accordance with TM 5-total thickness of pavement plus base for class A820-2/AFM 88-5, Chap. 2. through D roads and streets be less than 6 inches

6-4. Selection of Design CBR. Because of the chapter 18 when frost conditions are controlling.effects of processing samples for the laboratory TM 5-822-5/AFM 88-7, Chap. 1CBR tests and because of the effects of the test

able thickness of base course will be 4 inches as

nor less than frost design minimum specified in

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6-2

TM 5-822-5/AFM 88-7, Chap. 1

7-1

CHAPTER 7

BITUMINOUS PAVEMENT

7-1. General. or tar) should normally be based on economy.The bituminous materials used in paving are as-phaltic or tar products as listed in TM 5-822-8/AFM 88-6, Chap 9. Although asphalts and tars re-The basic criteria for selection and design of bitu-semble each other in general appearance, they do minous pavements are contained in TM 5-822-8not have the same physical or chemical character- which includes the following criteria:istics. Tars are affected to a greater extent by tem-a. Selection of bitumen type.perature changes and whether conditions; however, b. Selection of bitumen grade.they tend to have better adhesive and penetrating c. Aggregate requirements.properties than asphalts. Generally asphalt surfaced. Quality requirements.courses are preferred to tar surface courses. The e. Types of bituminous pavements.selection of the type of bituminous material (asphalt

7-2. Criteria for Bituminous Pavements.

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8-1

CHAPTER 8

FLEXIBLE PAVEMENT DESIGN

8-1. General. instances, be modified rather than stabilized. InFlexible pavement designs will provide the follow-ing:

a. Sufficient compaction of the subgrade and ofeach layer during construction to prevent objec-tionable settlement under traffic.

b. Adequate drainage of base course.c. Adequate thickness above the subgrade and

above each layer together with adequate quality ofthe select material, subbase, and base courses toprevent detrimental shear deformation under trafficand, when frost conditions are a factor, to controlor reduce to acceptable limits effects of frost heaveor permafrost degradation.

d. A stable, weather-resistant, wear-resistant wa-terproof, nonslippery pavement.

8-2. Design Procedure. parking areas, open storage, and similar areas willa. Conventional flexible pavements. In designing

conventional flexible pavement structures, thedesign values assigned to the various layers areapplied to the curves and criteria presented herein.Generally, several designs are possible for a specificsite, and the most practical and economical designis selected. Since the decision on the practicabilityof a particular design may be largely a matter ofjudgment, full particulars regarding the selection ofthe final design (including cost estimates) will beincluded in the design analysis. For computer aideddesign, see paragraph 1-6.

b. Stabilized Soil Layers. Flexible pavementscontaining stabilized soil layers are designedthrough the use of equivalency factors. A conven-tional flexible pavement is first designed and the Thickness design requirements are given in figure 8-equivalency factors applied to the thickness of the 1 in terms of CBR and design index. Minimumlayer to be stabilized. When stabilized materials thickness requirements are shown in table 6-1. Formeeting all gradation, durability, and strength re- frost condition design, thickness requirements willquirements indicated in TM 5-822-4, and in chap ter be determined from chapter 18 of this manual. In17 herein are utilized in pavement structures, an regions where the annual precipitation is less thanappropriate equivalency factor may be applied. Soils 15 inches and the water table (including perchedwhich have been mixed with a stabilizing agent andwater table) will be at least 15 feet below thewhich do not meet the requirements for a stabilizedfinished pavement surface, the danger of highsoil are considered modified and are designed as moisture content in the subgrade is reduced. Whereconventional pavement layers. When portland in-place tests on similar construction in thesecement is used to stabilize base course materials inregions indicate that the water content of theAir Force Pavements, the treatment level must be subgrade will not increase above the optimum, themaintained below approximately 4 percent by total pavement thickness, as determined by CBRweight to minimize shrinkage cracking which will tests on soaked samples, may be reduced by asreflect through the bituminous concrete surface much as 20 percent. The minimum thickness ofcourse. In this case, the base course will, in most pavement and base course must still be met; there-

addition, when unbound granular layers areemployed between two bound layers (e.g., an un-bound base course between an asphalt concrete(AC) surface course and a stabilized subbasecourse), it is imperative that adequate drainage beprovided the unbound layer to prevent entrapmentof excessive moisture in the layer. Additional in-formation on soil stabilization may be - obtainedfrom TM 5-818-1.

c. All-bituminous concrete. All-bituminous con-crete pavements are also designed using equivalencyfactors (see para 8-6). The procedure is the same asfor stabilized soil layers discussed above.

8-3. Design Index.The design of flexible pavements for roads, streets,

be based on a design index, which is an index rep-resenting all traffic expected to use a flexiblepavement during its life. It is based on typicalmagnitudes and compositions of traffic reduced toequivalents in terms of repetitions of an 18,000-pound, single-axle, dual-tire load. Selection of thedesign index will be accomplished as stated inchapter 3. The designer is cautioned that in select-ing the design index, consideration will be given totraffic which may use the pavement structure duringvarious stages of construction and to otherforeseeable exceptional use.

8-4. Thickness Criteria-Conventional FlexiblePavements.

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8-2

fore the reduction Will be affected in the subbase consideration will be given to the sensitivity of thecourse immediately above the subgrade. when onlysubgrade to small increases in moisture contentlimited rainfall records are available, or the annual before any reduction in thickness is made.precipitation is close to the 15-inch criterion, careful

8-5. Example Thickness Design-Conventional requirements will necessitate an increase inFlexible Pavements. subgrade density to a depth of 9 inches below theThis example illustrates design by the CBR methodwhen the subgrade, subbase, or base coursematerials are not affected by frost. Assume that adesign is to be prepared for a road that will requirea design index of 5. Further assume that compaction

subgrade surface and that a soft layer occurs withinthe subgrade 24 inches below the subgrade surface.The CBR design values of the various subgradelayers and the materials available for subbase andbase course construction are as follows:

TM 5-822-5/AFM 88-7, Chap. 1

8-3

The total thickness and thicknesses of the varioussubbase and base layers are determined as follows:

a. Total thickness. The total thickness of sub-base, base, and pavement will be governed by theCBR of the compacted subgrade. From the flexible-pavement design curves shown in figure 8-1, therequired total thickness above the compacted sub-grade (CBR of 10) is 11 inches. A check must bemade of the adequacy of the strength of the un-compacted subgrade and of the weak layer withinthe subgrade. From the curves in figure 8-1, therequired cover for these two layers is 14.5 and 21inches, respectively. If the design thickness is 11inches and the subgrade is compacted to 9 inchesbelow the subgrade surface, the natural subgradewill be covered by a total of 20 inches of higherstrength material. Similarly, the soft layer occurring24 inches below the subgrade surface will beprotected by 35 inches of total cover. Thus, thecover is adequate in both cases.

b. Minimum base and pavement thicknesses. Fora design index of 5 the minimum base thickness is 4inches and the pavement thickness is 2 inches asindicated in table 6-1. If, however, the CBR of thebase material had been 100 rather than 80, aminimum pavement thickness of 2 inches wouldhave been required.

c. Thickness of subbase and base courses. Thedesign thickness of each layer of materials 1 and 2will depend upon the CBR design value of eachmaterial. The total thickness of subbase, base, andpavement, as determined above, is 11 inches. Thethickness required above material 1 (CBR = 35), asdetermined from figure 8-1, is 3 inches; therefore,the required thickness of material 1 is 8 inches (11 -3 inches). The 3-inch layer required above material1 will be composed of material 2 and pavement;however, adjustments must be made in thethicknesses of material 2 and the pavement toconform with minimum base and pavementthickness, which is a combined thick-ness of

pavement and base of 6 inches (2 inches ofpavement and 4 inches of base). Therefore, thesection using materials 1 and 2 will consist of a 4.5-inch subbase course of material 1, a 4-inch basecourse of material 2, and a 2-inch pavement.

8-6. Thickness Criteria-Stabilized Soil Layers.a. Equivalency factors. The use of stabilized soil

layers within a flexible pavement provides the op-portunity to reduce the overall thickness of pave-ment structure required to support a given load. Todesign a pavement containing stabilized soil layersrequires the application of equivalency factors to alayer or layers of a conventionally designedpavement. To qualify for application of equivalencyfactors, the stabilized layer must meet appropriatestrength and durability requirements set forth in TM5-822-4. An equivalency factor represents thenumber of inches of a conventional base or subbasewhich can be replaced by 1 inch of stabilizedmaterial. Equivalency factors are determined asshown in table 8-1 for bituminous stabilizedmaterials, and from figure 8-2 for materialsstabilized with cement, lime, or a combination offlyash mixed with cement or lime. Selection of anequivalency factor from the tabulation is dependentupon the classification of the soil to be stabilized.Selection of an equivalency factor from figure 8-2requires that the unconfined compressive strengthas determined in accordance with ASTM D 1633 beknown. Equivalency factors are determined fromfigure 8-2 for subbase materials only. Therelationship established between a base and subbaseis 2 to 1. Therefore, to determine an equivalencyfactor for a stabilized base course, divide thesubbase factor from figure 8-2 by 2.

TM 5-822-5/AFM 88-7, Chap. 1

8-4

b. Minimum thickness. The minimum thickness 8-7. Example Thickness Design-Stabilized Soilrequirements for a stabilized base or subbase is 4 Layers.inches. The minimum thickness requirements for theasphalt pavement are the same as shown forconventional pavements in table 6-1.

To use the equivalency factors requires that a con-ventional flexible pavement be designed to supportthe design load conditions. If it is desired to use a

TM 5-822-5/AFM 88-7, Chap. 1

8-5

stabilized base or subbase course, the thickness ofconventional base or subbase is divided by theequivalency factor for the applicable stabilized soil.Examples for the application of the equivalencyfactors are as follows

a. Example 1. Assume a conventional flexiblepavement has been designed which requires a totalthickness of 16 inches above the subgrade. Theminimum thickness of AC and base is 2 and 4inches, respectively, and the thickness of subbase is10 inches. It is desired to replace the base andsubbase with a cement-stabilized gravelly soilhaving an unconfined compressive strength of 890psi. From figure 8-2 the equivalency factor for asubbase having an unconfined compressive strengthof 890 is 2.0. Therefore, the thickness of stabilizedsubbase is 10 inches 2.0=5.0 inches. To calculatethe thickness of stabilized base course, divide thesubbase equivalency factor by 2 and then divide theunbound base course thickness by the result.Therefore, 4 inches 1.0 = 4.0 inches of stabilizedbase course. The final section would be 2 inches ofAC and 9 inches of cement-stabilized gravelly soil.The base course thickness of 4.0 inches would alsohave been required due to the minimum thickness ofstabilized base.

b. Example 2. Assume a conventional flexiblepavement has been designed which requires 2 inchesof AC surface, 4 inches of crushed stone base, and6 inches of subbase. It is desired to construct an all-bituminous pavement (ABC). The equivalencyfactor from table 8-1 for a base course is 1.15 andfor a subbase is 2.30. The thickness of AC requiredto replace the base is 4 inches 1.15=3.5 inches,and the thickness of AC required to replace thesubbase is 6 inches 2.30 = 2.6 inches. Therefore,the total thickness of the ABC pavement is2+3.5+2.6 or 8.1 inches, which would be roundedto 8.0 inches.

8-8. Shoulders and Similar Areas.These areas are provided only for the purpose ofminimizing damage to vehicles which use them ac-cidentally or in emergencies; therefore, they are notconsidered normal vehicular traffic areas. Normally,only shoulders for class A roads will be paved.Others will be surfaced with soils selected for theirstability in wet weather and will be compacted asrequired. Dust and erosion control will be providedby means of vegetative cover, anchored mulch,coarse-graded aggregate, or liquid palliatives (TM5-830-3/AFM 88-17, Chap 3). Shoulders will notblock base-course drainage, particularly where frost

conditions are a factor. Where paving of shouldersis deemed necessary, the shoulders will be designedas a class F road or street.

8-9. Bituminous Sidewalks.Permanent bituminous sidewalks will consist of a 4-inch-thick base with a 1-inch-thick bituminoussurfacing. Material used locally in base constructionfor roads will normally be suitable as sidewalk basematerial. Bases may also be constructed of soilsstabilized or modified in place with portlandcement, lime, bituminous materials, or otheracceptable stabilizers. In frost and permafrost areas,bases of sidewalks should be nonfrost-susceptible.The bituminous surfacing may consist of hot- orcold-mix bituminous concrete, sand-asphalt or sand-tar mixes, or sheet asphalt; in locations where thesurface texture is not of prime importance,bituminous surface treatments may be used.Temporary walks or walks that are seldom used willbe constructed of stable or stabilized soils or rockscreenings containing granular and colloidalmaterials combined in the proportions necessary toensure maximum density and stability under variedweather conditions, including frost action. Wherenecessary, the life of these walks may be prolongedby the application of bituminous surface treatmentsor by the addition of suitable stabilizing agents. Theuse of soil sterilants may be considered to preventvegetation growth through bituminous sidewalks.

8-10. Bituminous Driveways.Base course materials in residence driveway areaswill be compacted to not less than 100 percent, andthe top 6 inches of the subgrade to not less than 90percent (95 percent for cohesionless sands andgravels) of the maximum density from ASTM D1557. Minimum base course thicknesses for resi-dence driveways are as follows:

The minimum paving requirements for residencedriveways are a multiple bituminous surface treat-ment for base course CBR values less than 80 anda single-bituminous surface treatment for CBRvalues of 80 or above.

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8-6

8-11. Curbs and Gutters. gutters will not block the drainage of base courseCurbs and gutters will be provided with a founda-tion at least 4 inches thick of material of 50-CBRminimum. The material will be nonfrost-susceptiblewhen required and will be compacted to the same For the design of flexible pavement overlays, seerequirements as the base or subbase course at the chapter 14 of this manual.same elevation. The foundation for curbs and

(TM 5-822-2/AFM 88-7, Chap 5).

8-12. Flexible Overlay Design.

TM 5-822-5/AFM 88-7, Chap. 1

9-1

CHAPTER 9

RIGID PAVEMENT DESIGN

9-1. Soil Classification and Tests. All soils density from ASTM D 1557, no rolling is necessaryshould be classified according to the Unified Soil other than that required to provide a smoothClassification System (USGS) as given in ASTM D surface. Compaction requirements for cohesive soils2487. There have been instances in construction (LL > 25; PI > 5) will be 90 percent of maximumspecifications where the use of such terms as density for the top 6 inches of cuts and the full"loam," gumbo, "mud," and "muck" have resulted depth of fills. Compaction requirements forin misunderstandings. These terms are not specificcohesionless soils (LL < 25: PI

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9-2

pavement, or drainage facilities construction.vail at the proposed site. Table 9-1 presents typical

9-4. Determination of Modulus of Subgrade conditions. These values should be considered as aReaction. For the design of rigid pavements in guide only, and their use in lieu of the field plate-those areas where no previous experience regardingbearing test, although not recommended, is left topavement performance is available, the modulus ofthe discretion of the engineer. Where a base coursesubgrade reaction k to be used for design purposesis used under the pavement, the k value on top ofis determined by the field plate-bearing test. This the base is used to determine the pavementtest procedure and the method for evaluating its thickness. The plate-bearing test may be run on topresults are given in MIL-STD-621A. Where per- of the base, or figure 9-1 may be used to determineformance data from existing rigid pavements are the modulus of soil reaction on top of the base. It isavailable, adequate values for k can usually be de- good practice to confirm adequacy of the k on toptermined on the basis of consideration of soil type,of the base from figure 9-1 by running a field plate-drainage conditions, and frost conditions that pre- load test.

values of k for various soil types and moisture

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9-3

TM 5-822-5/AFM 88-7, Chap. 1

10-1

CHAPTER 10

RIGID PAVEMENT BASE COURSES

10-1. General Requirements.Base courses may be required under rigid pave-ments for replacing soft, highly compressible or ex-pansive soils and for providing the following.

a. Additional structural strength.b. More uniform bearing surface for the pave-

ment.c. Protection for the subgrade against detrimen-

tal frost action.d. Drainage.e. Suitable surface for the operation of construc-

tion equipment, especially slipform pavers.

Use of base courses under a rigid pavement to pro-vide structural benefit should be based on econ.-myof construction. The first cost is usually less for anincrease in thickness than for providing a thick basecourse. However, thick base courses have oftenresulted in lower maintenance costs since the thickbase course provides stronger foundation andtherefore less slab movement. A minimum base-course thickness of 4 inches is required oversubgrades that are classified as OH, CH, CL, MH,ML, and OL to provide protection against pumping.In certain cases of adverse moisture conditions(high water table or poor drainage), SM and SCsoils also may require base courses to preventpumping. The designer is cautioned against the useof fine-grained material for leveling courses orchoking open-graded base courses since this maycreate a pumping condition. Positive drainageshould be provided for all base courses to ensurewater is not trapped directly beneath the pavementsince saturation of these layers will cause thepumping condition that the base course is intendedto prevent. The base course material and drainsmust meet the drainage criteria listed in TM 5-820-2/AFM 88-5, Chap. 2.

10-2. Materials.If conditions indicate that a base course is desirableunder a rigid pavement, a thorough investigationshould be made to determine the source, quantity,and characteristics of the available materials. Astudy should also be made to determine the mosteconomical thickness of material for a base coursethat will meet the requirements. The base coursemay consist of natural, processed, or stabilizedmaterials. The material selected should be the onethat best accomplishes the intended purpose of thebase course. In general, the base- course materialshould be a well-graded, high-stability material. Inthis connection all base courses to be placedbeneath concrete pavements for military roads andstreets should conform to the fol-lowingrequirements:

a. Percent passing No.10 sieve; Not more than85.

b. Percent passing No.200 sieve: Not more than15.

c. Plasticity index: Not higher than 6.Where local experience indicates their desirability,other control limitations such as limited abrasionloss may be imposed to ensure a uniform high-quality base course.

10-3. Compaction.Where base courses are used under rigid pavements,the base-course material should be compacted to aminimum of 95 percent of the maximum density.The engineer is cautioned that it is difficult tocompact thin base courses to high densities whenthey are placed on yielding subgrades.

10-4. Frost Requirements.In areas where subgrade soils are subjected to sea-sonal frost action detrimental to the performance ofpavements, the requirements for base-coursethickness and gradation will follow the criteria inchapter 18 of this manual.

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11-1

CHAPTER 11

CONCRETE PAVEMENT

11-1. Mix Proportioning and Control. used for concrete with the maximum size aggregateProportioning of the concrete mix and control ofthe concrete for pavement construction will be inaccordance with TM 5-822-7. Normally, a designflexural strength at 28-day age will be used for thepavement thickness determination. Should it benecessary to use the pavements at an earlier age,consideration should be given to the use of a designflexural strength at the earlier age or to the use ofhigh early strength cement, whichever is more Mix proportion or pavement thickness may have toeconomical. Flyash gains strength more slowly thanbe adjusted due to results of concrete tests. If thecement, so that if used it may be desirable to selecttests show a strength gain less than predicted or aa strength value at a period other than 28 days if retrogression in strength, then the pavement wouldtime permits. have to be thicker. If the concrete strength was

11-2. Testing. reduced. Rather than modifying the thicknessThe flexural strength of the concrete and lean con-crete base will be determined in accordance withASTM C 78. The standard test specimen will be a6- by 6-inch section long enough to permit testingover a span of 18 inches. The standard beam will be

up to 2 inches. When aggregate larger than the 2-inch nominal size is used in the concrete, the cross-sectional dimensions of the beam will be at leastthree times the nominal maximum size of theaggregate, and the length will be increased to atleast 2 inches more than three times the depth.

11-3. Special Conditions.

higher than predicted, then the thickness may be

required as a result of tests on the concrete, the mixproportioning could be changed to increase ordecrease the concrete strength, thereby not chang-ing the thickness.

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12-1

CHAPTER 12

PLAIN CONCRETE PAVEMENT DESIGN

12-1. General. tained from the design chart presented in figure 12-Rigid pavements for roads, streets, and open stor-age areas at military installations will be plain(nonreinforced) concrete except for those condi-tions listed in chapter 13 or unless otherwise ap-proved by HQUSACE (CEMP-ET), or theappropriate Air Force Major Command.

12-2. Roller-Compacted Concrete Pavements.Roller-compacted concrete pavements (RCCP) areplain concrete pavements constructed using a zero-slump portland cement concrete mixture that isplaced with an AC paving machine and compactedwith vibratory and rubber-tired rollers. The designof RCCP is presented in chapter 17.

12-3. Design Procedure.For convenience in determining design require-ments, the entire range of vehicle loadings andtraffic intensities anticipated during the design lifeof pavements for the various classifications of mili-tary roads and streets has been expressed as anequivalent number of repetitions of an 18,000-pound single-axle loading. To further simplify thedesign procedure, the range of equivalent repeti-tions of the basic loading thus determined has beendesignated by a numerical scale defined as thepavement design index. This index extends from 1through 10 with an increase in numerical valueindicative of an increase in pavement designrequirements. Values for the design index are de-termined using the procedure in chapter 3. Once thedesign index has been determined the requiredthickness of plain concrete pavement is then ob-

1 for roads and streets. Figure 12-2 is used todetermine the thickness of parking and storageareas except that the thickness of roller-compactedconcrete parking and storage areas will be designedusing figure 12-1. These design charts are graphicalrepresentations of the interrelation of flexuralstrength, modulus of subgrade reaction k, pavementthickness, and repetitions (design index) of the basic18,000-pound single-axle loading. These designcharts are based on the theoretical analyses ofWestergaard (New Formulas for Stresses inConcrete Pavements of Airfields, ASCETransactions), supplemented by empirical modifi-cations determined from accelerated traffic tests andobservations of pavement behavior under actualservice conditions. The design charts are enteredusing the 28-day flexural strength of the concrete.A horizontal projection is then made to the right tothe design value for k. A vertical projection is thenmade to the appropriate design-index line. A secondhorizontal projection to the right is then made tointersect the scale of pavement thickness. Thedashed line shown on curves is an example of thecorrect use of the curves. When the thickness fromthe design curve indicates a fractional value, it willbe rounded up to the next -inch thickness. Allplain concrete pavements will be uniform in cross-sectional thickness. Thickened edges are notnormally required since the design is for free edgestresses. The minimum thickness of plain concretefor any military road, street, or open storage areawill be 6 inches.

TM 5-822-5/AFM 88-7, Chap. 1

12-2

TM 5-822-5/AFM 88-7, Chap. 1

12-3

12-4. Design Procedure for Stabilized Founda- h = thickness of plain concrete pavement over-tions. lay required over the stabilized layer, inchesThe thickness requirements for a plain concretepavement on a modified soil foundation will be de-signed as if the layer is unbound using the k valuemeasured on top of the modified soil layer. For sta-bilized soil layers, the treated layer will be consid-ered to be a low-strength base pavement and thethickness determined using the following modifiedpartially bonded overlay pavement design equation:

where

o

h = thickness of plain concrete pavement fromddesign chart (fig. 12-1) based on k value ofunbound material, inches

E = flexural modulus of elasticity of the stabi-flized soil. The modulus value for bituminousstabilized soils will be determined accordingto the procedures in appendix B. The modulusvalue for lime and cement stabilized soils willbe determined using the results of CRD-C 21and the equations in appendix B

h = thickness of stabilized layer, inchess

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12-4

For additional information on stabilization and mixchapter 3, the 50-kilopounds (kip) tracked vehiclesproportioning see TM 5-822-4 and TM 5-818-1.would be classified as category V traffic. For a fire-

12-5. Design Examples. pavement design index would be 6. The 80-kipAs an example of the application of the design pro-cedures given for nonstabilized foundations, designa plain concrete pavement for a road in a rural areaon rolling terrain to carry the following traffic:

Based on the criteria in TM 5-822-2/AFM 88-7,Chap 5, this traffic would be evaluated as requiringa class C road. It would be designed for categoryIV traffic and a design index of 5. Assuming a 28-day flexural strength for the concrete of 675 psi,and a k value of 100 pounds per cubic inch (pci),the required pavement thickness as indicated byfigure 12-1 is approximately 7.3 inches. This thick-ness value would be rounded off to 7.5 inches fordesign. To illustrate the design procedure whentraffic includes tracked vehicles, assume that inaddition to the pneumatic-tired traffic used in theprevious example, the designer must provide for anaverage of 60 tanks per lane per day and that thegross weight of each tank is 50,000 pounds. The50,000-pounds gross weight would be classified asPortland cement concrete walks may be provided atcategory V traffic (according to chapter 3) since itinstallations where pedestrian traffic justifies thisexceeds the maximum of 40,000 pounds permittedtype of construction. Normally, the design thicknessfor tracked vehicles in category IV traffic. Inasmuch for walks will be 4 inches. Where it is necessary andas the tank traffic exceeds 40 per day, the rigid desirable to continue the walk across driveways andpavement design index would be based on the nextprivate entrances, provided for vehicle crossings,higher traffic volume given in table 3-1, which is the thickness of the walk should be increased to100 per day. Thus, the design index for a class C provide sufficient strength to support the vehicularstreet would be 6. Assuming the same 28-day loads to which such portions of the walks will beflexural strength and k value as in the previous subjected. Concrete walks should be groovedexample, the required pavement thickness is transversely into rectangular areas with the longestapproximately 7.75 inches (fig 12-1) and would re-dimension no greater than 1.25 times the shorterquire a design thickness of 8.0 inches. To illustratedimension to create planes of weakness for controlthe procedure for combining tracked vehicles withof contraction cracking. The depth of such groovespneumatic-tired vehicles, design a rigid pavement should be a minimum of one-fourth the thickness ofon rolling terrain for the following traffic: the slab and need not be sealed. Expansion joints

According to TM 5-822-2/AFM 88-7, Chap 5, thefor such joints should be not less than 30 feet nortraffic on rolling terrain would be evaluated as re- more than 50 feet. A base is only recommended atquiring a class D road or class E street. From locations where past experience has shown that sub-

quench of 50 of these vehicles per lane per day, the

tracked vehicles are classified as category VI traffic.For a frequency of 20 of these vehicles per lane perday, the pavement design index would be 7. Thus,it can be seen that the 80-kip tracked vehicle trafficgoverns as it requires the highest design index.Assuming the same 28-day flexural strength and kvalue as in the previous design examples, therequired pavement thickness is 8.1 inches (fig 12-1)which would be rounded to 8.5 inches for design.For this same example, if the plain concretepavement is to be placed on 6 inches of cementstabilized soil having an E~ value of 500,000 psi,then the thickness of plain concrete require wouldbe as follows using equation 12-1.

Design examples for rigid pavement for frost con-ditions are discussed in chapter 18.

12-6. Concrete Sidewalks.

consisting of approved preformed bituminous filleror wood approximately inch thick should beinstalled to surround or to separate all structures orfeatures which project through or against thesidewalk slab. Expansion joints of a similar typeshould be installed at regularly spaced intervalstransversely across the sidewalk slab. The spacing

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grade soils exhibit unacceptable swell and frost 50 pci, and when frost penetrates a frost-susceptibleheave potential. These soils can result in safety material underlying the rigid pavement on small jobsproblems with differential joint elevations. in frost areas. Where the flexural strength or

12-7. Concrete Driveways. inches of concrete with a 6-inch base course.Under normal conditions, rigid pavement for resi-dential driveways will be either 6-inch plain con-crete or 5-inch reinforced concrete with 0.10 per-cent of reinforcement steel. In plain concrete pave-ment design, slab lengths will not exceed 15 feetwith 12 feet recommended. For reinforced pave-ment, slab lengths up to 30 feet may be used. Theresidential driveways will be 6 inches thick and re-inforced with a minimum of 0.05 percent of rein-forcement steel when the following adverse condi-For a discussion of the design of curbs, gutters, andtions prevail: when concrete flexural strength is shoulders, see paragraphs 8-8 and 8-11 of thisbelow 630 psi and the subgrade modulus k is belowmanual.

subgrade modulus is unknown, the design will be 6

Contraction or construction joints provided in adriveway will be designed and sealed in accordancewith chapter 15 or 16. Expansion joints consistingof approved preformed bituminous filler or woodshould be installed to surround or separate allstructures which project through or against thedriveway slabs.

12-8. Curbs, Gutters, and Shoulders.

TM 5-822-5/AFM 88-7, Chap. 1

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CHAPTER 13

REINFORCED CONCRETE PAVEMENTS

13-1. Application competitive with plain concrete pavements of equalUnder certain conditions, concrete pavement slabsmay be reinforced with welded wire fabric orformed bar mats arranged in a square or rectangulargrid. The advantages of using steel reinforcementinclude a reduction in the required slab thickness,greater spacing between joints, and reduceddifferential settlement due to nonuniform support orfrost heave.

a. Subgrade conditions. Reinforcement mayreduce the damage resulting from cracked slabs.Cracking may occur in rigid pavements founded onsubgrades where differential vertical movement is adefinite potential. An example is a foundation withdefinite or borderline frost susceptibility that cannotfeasibly be made to conform to conventional frostdesign requirements.

b. Economic considerations. In general, rein-forced concrete pavements will not be economically

load-carrying capacity, even though a reduction inpavement thickness is possible. Alternate bids,however, should be invited if reasonable doubtexists on this point.

c. Plain concrete pavements. In otherwise plainconcrete pavements, steel reinforcement should

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