army - fm5 436 - paving and surfacing operations

8/14/2019 Army - fm5 436 - Paving and Surfacing Operations

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FM 5-436

Paving andSurfacing

Operations

Headquarters,Department of the Army

DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.


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*FM 5-436

Field Manual HeadquartersNo. 5-436 Department of the Army

Washington, DC, 28 April 2000

Paving and Surfacing Operations

ContentsPage

PREFACE .................................................................................................................... x

INTRODUCTION ........................................................................................................ xi

Construction Principles ............................................................................................... xiStage Construction............................................................................................... xiSafe Construction................................................................................................. xi

Types of Pavements and Surfaces ............................................................................ xii

PART ONE BITUMINOUS PAVEMENTS AND SURFACES

Chapter 1 BITUMINOUS MATERIALS ..................................................................................... 1-1

Section I - Bitumen ................................................................................................. 1-2

Types of Bitumen ...................................................................................................... 1-2Asphalt................................................................................................................ 1-2Tar ...................................................................................................................... 1-2

Asphalt Cement ........................................................................................................ 1-2Asphalt Cutback ........................................................................................................ 1-3Asphalt Emulsion ...................................................................................................... 1-3Tar............................................................................................................................. 1-4

Section II - Aggregate ............................................................................................. 1-5

Function .................................................................................................................... 1-5Types of Aggregate................................................................................................... 1-5Characteristics .......................................................................................................... 1-6

Distribution Restriction: Approved for public release; distribution is unlimited.

______________________________

*This publication supersedes Technical Manuals (TMs) 5-331D, 21 April 1969; 5-337, 21 February 1966;and 5-337-1, 29 March 1971.


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Chapter 2 BITUMINOUS DESIGN ........................................................................................... 2-1

Bitumen Selection.................................................................................................... 2-1

Asphalt Cement ................................................................................................. 2-1Asphalt Cutback ................................................................................................ 2-1Asphalt Emulsion .............................................................................................. 2-5Tar ..................................................................................................................... 2-5

Aggregate Selection ................................................................................................ 2-5Mix Gradation .................................................................................................... 2-5Aggregate Blending. ........................................................................................ 2-10Example of Aggregate Blending ...................................................................... 2-15Reporting ......................................................................................................... 2-18

Optimum Bitumen Content .................................................................................... 2-18Reporting Test Results .................................................................................... 2-18Evaluating Test Results .................................................................................. 2-21

Job-Mix Formula .................................................................................................... 2-22

Chapter 3 EQUIPMENT USED IN BITUMINOUS OPERATIONS ........................................... 3-1

Section I - Production Equipment ........................................................................ 3-1

Asphalt Plant ........................................................................................................... 3-1Batch and Continuous-Mix Plants ........................................................................... 3-1

Cold-Feed Calibration ....................................................................................... 3-2Dryer ................................................................................................................. 3-3Dust Collector .................................................................................................... 3-3Screening .......................................................................................................... 3-3Percentage of Each Hot Bin .............................................................................. 3-3Mixing Aggregate and Asphalt .......................................................................... 3-4

Drum Mixer .............................................................................................................. 3-4Cold-Feed Calibration ....................................................................................... 3-5Dryer ................................................................................................................. 3-5

Storage Silo ............................................................................................................. 3-5Travel Plant ............................................................................................................. 3-5Liquid Handling Equipment...................................................................................... 3-5Hauling Equipment .................................................................................................. 3-6Support Equipment .................................................................................................. 3-6

Section II - Placement Equipment ........................................................................ 3-6

Truck-Mounted Asphalt Distributor .......................................................................... 3-6Trailer-Mounted (Tankless) Asphalt Distributor ....................................................... 3-8Asphalt Finisher ....................................................................................................... 3-8Compactors ........................................................................................................... 3-10

Static Steel-Wheel Rollers .............................................................................. 3-10Vibratory Steel-Wheel Rollers ......................................................................... 3-11Rubber-Tired Rollers ....................................................................................... 3-11Other Compaction Devices ............................................................................. 3-12

Motor Grader ......................................................................................................... 3-12Hand Tools ............................................................................................................ 3-12Aggregate Spreaders ............................................................................................ 3-14Surface-Treatment Combine ................................................................................. 3-15


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Chapter 4 PRODUCTION AND LAYDOWN OF BITUMINOUS MATERIALS ......................... 4-1

Section I - Fundamentals ....................................................................................... 4-1

Construction ............................................................................................................. 4-1Handling and Stockpiling Aggregate ........................................................................ 4-2Traffic Problems ....................................................................................................... 4-2

Section II - Prime and Tack Coats ........................................................................ 4-3

Prime Coat ............................................................................................................... 4-3Base Preparation ............................................................................................... 4-3Materials ............................................................................................................ 4-3Application ......................................................................................................... 4-4Curing Period ..................................................................................................... 4-5Protection ........................................................................................................... 4-5

Tack Coat ................................................................................................................. 4-5Materials ............................................................................................................ 4-5

Application ......................................................................................................... 4-5Curing Period ..................................................................................................... 4-6Protection ........................................................................................................... 4-6

Section III - Surface Treatment ............................................................................. 4-6

Single Surface Treatment ........................................................................................ 4-6Aggregate .......................................................................................................... 4-7Bituminous Material ........................................................................................... 4-8Rolling ................................................................................................................ 4-9Final Sweeping .................................................................................................. 4-9

Multiple Surface Treatment ...................................................................................... 4-9Dust Palliative ........................................................................................................ 4-10

Section IV - Penetration Macadam ..................................................................... 4-10

Concept.................................................................................................................. 4-10Materials................................................................................................................. 4-11Construction ........................................................................................................... 4-11

Recondition the Base Course .......................................................................... 4-13Construct Edges on the Wearing Surface ....................................................... 4-13Apply the Macadam Aggregate ....................................................................... 4-13Test the Course-Aggregate Thickness ............................................................ 4-14Apply the First Layer of Bituminous Material ................................................... 4-14Protect the Area ............................................................................................... 4-15Apply the Keystone .......................................................................................... 4-15Broom and Roll the Aggregate ........................................................................ 4-15Apply the Second Layer of Bituminous Material .............................................. 4-15

Apply the Choke Stone .................................................................................... 4-15Apply the Surface Treatment ........................................................................... 4-16Protect and Maintain the Pavement ................................................................. 4-16

Section V - Road-Mix Pavement ......................................................................... 4-16

Concept.................................................................................................................. 4-16Bitumen .................................................................................................................. 4-16Aggregate............................................................................................................... 4-17Mix Proportions ...................................................................................................... 4-17Construction ........................................................................................................... 4-18


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Prepare the Base ............................................................................................ 4-19Place and Windrow the Aggregate .................................................................. 4-19Mix the Materials ............................................................................................. 4-20Blade Thickened Edges .................................................................................. 4-21Spread and Shape the Mix .............................................................................. 4-21Roll the Finished Surface ................................................................................ 4-22Shape the Edges ............................................................................................. 4-22Take Samples ................................................................................................. 4-22Treat the Surface ............................................................................................ 4-22

Section VI - Plant-Mix Pavement ........................................................................ 4-22

Concept ................................................................................................................. 4-22Hot-Mix Bituminous Concrete ................................................................................ 4-23Cold-Laid Bituminous Plant Mix............................................................................ 4-25

Bituminous Materials ............................................................................................. 4-26Laying a Hot M i x ................................................................................................. 4-26

Determining the Placement Temperature ....................................................... 4-27Inspecting and Rejecting the Mix .................................................................... 4-27Placing and Spreading the Mix ....................................................................... 4-28Computing the Depth ...................................................................................... 4-29Adjusting the Screed ....................................................................................... 4-30Raking the Mix ................................................................................................ 4-31Adjusting the Mix ............................................................................................. 4-31Rolling the Pavement ...................................................................................... 4-31

Density Tests ......................................................................................................... 4-33Selecting and Marking Samples ...................................................................... 4-34Removing Samples ......................................................................................... 4-35Identifying Samples ......................................................................................... 4-35

Correcting Low Density ................................................................................... 4-35Longitudinal Joints ................................................................................................. 4-36Construction .................................................................................................... 4-36Alignment ........................................................................................................ 4-38

Transverse Joints .................................................................................................. 4-38Terminating a Lane ......................................................................................... 4-38Rolling a Transverse Joint. .............................................................................. 4-39Constructing Pavement Ends .......................................................................... 4-39

Section VII - Special Mixes ................................................................................. 4-40

Sand Asphalt and Tar ............................................................................................ 4-40Sheet Asphalt ........................................................................................................ 4-40Stone-Filled Sheet Asphalt .................................................................................... 4-40Rock Asphalt ......................................................................................................... 4-41

Chapter 5 FIELD MANUFACTURE OF ASPHALT CUTBACKS ............................................ 5-1

Equipment and Production Rate.............................................................................. 5-1Safety ...................................................................................................................... 5-2Procedures .............................................................................................................. 5-3

Drums ................................................................................................................ 5-4Asphalt Cement ................................................................................................. 5-5Temperature ...................................................................................................... 5-5


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Material Requirements ............................................................................................. 5-5

Chapter 6 MATERIAL ESTIMATES ......................................................................................... 6-1

Prime Coat ............................................................................................................... 6-1Tack Coat ................................................................................................................. 6-2Surface Treatment ................................................................................................... 6-2Penetration Macadam .............................................................................................. 6-3Road Mix .................................................................................................................. 6-5Plant Mix .................................................................................................................. 6-5Mileage Requirements ............................................................................................. 6-6

Chapter 7 MAINTAINING AND REPAIRING BITUMINOUSWEARING SURFACES ........................................................................................... 7-1

Principles.................................................................................................................. 7-1

Materials................................................................................................................... 7-1Inspections ............................................................................................................... 7-2Causes of Failure ..................................................................................................... 7-2Types of Failure ....................................................................................................... 7-3

Potholes ............................................................................................................. 7-3Raveling ............................................................................................................. 7-4Cracking ............................................................................................................. 7-4Rutting and Shoving .......................................................................................... 7-4Corrugation ........................................................................................................ 7-4Burned Areas ..................................................................................................... 7-5Bleeding ............................................................................................................. 7-5Settlements and Depressions ............................................................................ 7-5

Patches .................................................................................................................... 7-5

Premixed Patch ................................................................................................. 7-5Penetration Patch .............................................................................................. 7-9Skin Patch ........................................................................................................ 7-10Seal Coat ......................................................................................................... 7-10

Craters ................................................................................................................... 7-11

PART TWO CONCRETE PAVEMENTS

Chapter 8 COMPONENTS OF CONCRETE ............................................................................ 8-2

Types of Portland Cement ....................................................................................... 8-2Water........................................................................................................................ 8-3

Sea Water .......................................................................................................... 8-3

Well Water (Sulfur) ............................................................................................ 8-3Aggregate................................................................................................................. 8-3

Types ................................................................................................................. 8-4Characteristics ................................................................................................... 8-4Gradations ......................................................................................................... 8-4Fineness Modulus .............................................................................................. 8-5Blending ............................................................................................................. 8-5

Admixtures ............................................................................................................... 8-5Air-Entraining Agents ......................................................................................... 8-6


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Accelerators ...................................................................................................... 8-6Retardants ......................................................................................................... 8-6Plasticizers ........................................................................................................ 8-6

Materials Handling and Storage .............................................................................. 8-7Aggregate .......................................................................................................... 8-7Cement .............................................................................................................. 8-7

Chapter 9 CHARACTERISTICS OF CONCRETE ................................................................... 9-1

Plastic Concrete ...................................................................................................... 9-1Hardened Concrete ................................................................................................. 9-1Air-Entrained Concrete ............................................................................................ 9-2

Production ......................................................................................................... 9-2Measurement of Air Content ............................................................................. 9-3Slump ................................................................................................................ 9-3Strength ............................................................................................................. 9-3

Chapter 10 MIX DESIGN ......................................................................................................... 10-1

Criteria ................................................................................................................... 10-1Water-to-Cement Ratio ................................................................................... 10-1Aggregate ........................................................................................................ 10-3Workability ....................................................................................................... 10-3

Methods................................................................................................................. 10-3Book Method ................................................................................................... 10-4Trial-Batch Method .......................................................................................... 10-7

Chapter 11 CONCRETE EQUIPMENT .................................................................................... 11-1

Concrete Mixer ...................................................................................................... 11-1Pneumatic Concrete Vibrator ................................................................................ 11-1Concrete Saw ........................................................................................................ 11-2Pin Puller ............................................................................................................... 11-2Water Heater ......................................................................................................... 11-2Concrete Bucket .................................................................................................... 11-2Supporting Equipment ........................................................................................... 11-2Central Mix Plant ................................................................................................... 11-3M919 Concrete Mobile .......................................................................................... 11-3

Chapter 12 FORMS AND JOINTS ........................................................................................... 12-1

Section I - Forms ................................................................................................. 12-1

Procedures ............................................................................................................ 12-2Construction .......................................................................................................... 12-2Placement and Alignment...................................................................................... 12-2Handling ................................................................................................................ 12-3

Section II - Joints ................................................................................................. 12-4

Types of Joints ...................................................................................................... 12-4Construction .................................................................................................... 12-4Expansion ....................................................................................................... 12-4Contraction ...................................................................................................... 12-5


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Dowels ................................................................................................................... 12-5Installation of Joints................................................................................................ 12-6

Longitudinal Construction Joints ...................................................................... 12-7Transverse Construction Joints ....................................................................... 12-7Expansion Joints .............................................................................................. 12-7Concrete Placement ........................................................................................ 12-7Final Positions ................................................................................................. 12-8Joint Surfaces .................................................................................................. 12-8Contraction Joints ............................................................................................ 12-8Hand-Formed Joints ........................................................................................ 12-8Sawed Joints ................................................................................................... 12-9

Sealing Joints......................................................................................................... 12-9

Chapter 13 CONCRETE PAVING ............................................................................................ 13-1

Section I - Material Measurements and Truck Requirements .......................... 13-1

Cement................................................................................................................... 13-1Water...................................................................................................................... 13-1Aggregate............................................................................................................... 13-2

Weight Measurement ....................................................................................... 13-2Volume Measurement ...................................................................................... 13-2

Truck Requirements............................................................................................... 13-2

Section II - Procedures ........................................................................................ 13-3

Sequence of Operations ........................................................................................ 13-3Prepare the Subgrade............................................................................................ 13-3Mix the Concrete .................................................................................................... 13-4Transport the Concrete .......................................................................................... 13-5Prepare Expansion Joints ...................................................................................... 13-6Place the Concrete................................................................................................. 13-6Vibrate the Concrete .............................................................................................. 13-6Finish the Surface .................................................................................................. 13-7

Spreading ........................................................................................................ 13-7Hand Finishing and Floating ............................................................................ 13-8Straightedge Finishing ..................................................................................... 13-8Burlap Drag Finishing ...................................................................................... 13-8

Prepare Contraction Joints..................................................................................... 13-9Finish the Edges .................................................................................................... 13-9Cure the Concrete .................................................................................................. 13-9

Burlap or Cotton Mat ........................................................................................ 13-9Waterproof-Paper Blanket or Impermeable Sheet ......................................... 13-10

Membrane ...................................................................................................... 13-10Seal Joints and Cracks ........................................................................................ 13-11Remove Forms..................................................................................................... 13-11Test the Surface................................................................................................... 13-11Test the Strength.................................................................................................. 13-11

Section III - Cold- and Hot-Weather Techniques ............................................. 13-11

Cold-Weather Construction.................................................................................. 13-11Frozen Subgrade ........................................................................................... 13-12Effect of Temperature .................................................................................... 13-13


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Heating Equipment ........................................................................................ 13-16Heat Preservation ......................................................................................... 13-16Placing and Finishing .................................................................................... 13-16Protection After Finishing .............................................................................. 13-16

Hot-Weather Construction ................................................................................... 13-17

Section IV - Reinforced and Prestressed Concrete ........................................ 13-18

Reinforced Concrete............................................................................................ 13-18Prestressed Concrete .......................................................................................... 13-20

Section V - Maintenance and Repair ................................................................ 13-21

Introduction.......................................................................................................... 13-21Types of Cement ................................................................................................. 13-21Repair of Joints and Cracks ................................................................................ 13-21Repair of Areas.................................................................................................... 13-22Repair of Breaks .................................................................................................. 13-23

Concrete Patches .......................................................................................... 13-23Cement-Bound Macadam Patches ............................................................... 13-24Bituminous Patches ...................................................................................... 13-24Emergency Patches ...................................................................................... 13-24

Settlements.......................................................................................................... 13-24

PART THREE EXPEDIENT OPERATIONS

Chapter 14 EXPEDIENT PAVEMENTS AND SURFACES ..................................................... 14-1

Materials ................................................................................................................ 14-2Special Considerations .......................................................................................... 14-2Roads .................................................................................................................... 14-3

Cross-Country Tracks............................................................................................ 14-3Army Tracks .......................................................................................................... 14-3Chespaling Mats .................................................................................................... 14-4Bamboo Mats ........................................................................................................ 14-4Sommerfeld Track ................................................................................................. 14-6

Construction .................................................................................................... 14-7Sommerfeld Sandwich .................................................................................... 14-7Monkton Pack ................................................................................................. 14-7

Wire Mesh ............................................................................................................. 14-7Chain-Link Wire Mesh ..................................................................................... 14-9Chicken Wire and Expanded Metal Lath ......................................................... 14-9

Heavy Expedient Roads and Pioneer Trails .......................................................... 14-9Mat Roads ..................................................................................................... 14-10Plank Roads .................................................................................................. 14-11Plank-Tread Roads ....................................................................................... 14-12Log-Tread and Log-Plank Roads .................................................................. 14-12Corduroy Roads ............................................................................................ 14-12Pioneer Roads .............................................................................................. 14-16

Mat Repair ........................................................................................................... 14-17Surface Repair With Brick ................................................................................... 14-17


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Appendix A METRIC CONVERSIONS ....................................................................................... A-1

Appendix B CHECKLIST FOR CONCRETE PAVING ............................................................... B-1

GLOSSARY ................................................................................................ Glossary-1

BIBLIOGRAPHY .................................................................................... Bibliography-1

INDEX .................................................................................................................Index-1
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PrefaceField Manu al (FM) 5-436 provides essent ial informat ion to milita ry personnel wh o are en gaged ino r r e spons ib le fo r b i tuminous and conc re t e ope ra t ions fo r roads and a i r f i e lds . I t con ta insinformation on construction materials and equipment and the mix design, production, placement,and repair of concrete and bituminous pavements.

Emphasis is primarily placed on the duties and responsibil i t ies of engineer platoon sergeants,p la toon leaders , company commanders , and s taff personnel dur ing bi tuminous and concreteoperations. In addition, technical engineering specialists (military occupational specialty [MOS]51T) are involved in quality cont rol of bituminous a nd concrete opera tions.

FM 5-436 is a compa nion p ublicat ion of FMs 5-410, 5-430-00-1, an d 5-430-00-2. It completes th eprocess of road and airfield construction.

Append ix A cont ains a metr ic conversion char t.

The proponent of this publication is HQ TRADOC. Forward comments and recommendations onDepartment of the Army (DA) Form 2028 to Commandant, United States Army Engineer School,ATTN: ATSE-TD-D, Fort Leonar d Wood, Missour i 65473-6650.

Unless this publication states otherwise, masculine nouns and pronouns do not refer exclusivelyto men.


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IntroductionCONSTRUCTION PRINCIPLES

The a dvent of devasta t ing weapons a nd the increased m obil ity of modern warfare ma ke i tposs ible for combat s i tes to be located anywhere . Const ruct ing roads and a i r f ie lds mustp roceed even aga ins t t r em endous d i ff icu l t i e s . The du ra b i li t y o f cons t ru ct ion an d o the rstandards may require the modification of plans based on

The immediate tactical or strategic si tuation. Urgen t factor s . The availabili ty of manpower, mat erials, and equipment. Cont inuous enemy at tack.

Underst anding constr uction principles helps engineers at tain the best constr uction possibleusing the materials available. Construction principles include making a sound plan for theroute, clearing t he r ight-of-way, evening out t he r oadbed, and m aking impr ovement s to t hesurface.

STAGE CONSTRU CTION

S t a g e c on s t r u c t io n i s t h e p l a n n e d e x p a n s i on (w i d t h o r d e p t h ) of a r o a d . R oa d s ca n b eexpanded (upgraded) us ing a minimum amount of t ime, manpower, and mater ia ls . S tageconst ruction in depth is a vital considera tion when plann ing combat -zone (CZ) roads. Flexiblepavements lend themselves to th is task . For example , an unsurfaced road was or ig inal lyconstructed in a CZ. As the combat area moves forward, surfacing the road with road-mix

pavement increases the traffic capacity. When the road is part of the rear area, engineers paveit with a hot or cold plant mix if increased durability is necessary or they treat the surface if increased su rface smoothn ess i s needed. The road could th en h andle th e h igh volume andheavy loads of rear-area traffic, assuming the base and subbase are adequate. Engineers mustensure that all layers are completely bonded.

As the load or amount of t raff ic increases , the road may need to be widened. During thep l a n n i n g s t a g e o f a n o r i g i n a l r o a d c o n s t r u c t i o n , e n g i n e e r s s h o u l d i n c l u d e w i d e n i n gallowances. For example, th ey plan for wide cut s a nd fi l ls t o allow for later road widening.(Most military widening operations are less than one lane width.)

SAFE CONSTRUCTION

En gineers m ust rigidly observe safety pr ecaut ions and procedures during pa ving operations

and when heating bitumens, especially if flammable materials are being used. They must alsoobserve proper t ra ffic mainten an ce procedures.


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TYPES OF PAVEMENTS AND SURFACES

This ma nu al a ddresses t he following types of paving an d su rfacing operations:

Bitum inous pavements and surfaces (Part One). Concrete pavements (Part Two). Expedient operations (Part Three).

NOTE: The term c o n c r e t e i n t h i s p u b l i c a t i o n r e f e r s t o p o r t l a n d - c e m e n t c o n c r e t eun les s spec i f i ed o the rwise .

Selecting the types of pavements and surfaces to construct is based on traffic conditions; theavai labi l i ty of equipment , manpower, and mater ia ls ; t ime a l lo t ted; c l imat ic and weathercond i t ions ; an d expected subgrade de forma t ions . E ng ineer s a re no t l imi t ed to us ing t heexpedient methods discussed in this m anu al. Soun d engineering principles and imaginationoften lead to improved expedient meth ods.

A pavement i s the end resul t of an opera t ion that contr ibutes to the overa l l load-bear ing

capacity of a structure: Bituminous pavement i s usually more than 1 inch t h ick, and concrete pavement i s

usually more than 6 inches thick. Flexible pavement gives or flexes under loads. Ideally, the load is distributed over a

surface area that is proportional to the distance of the area from the surface. Rigid pavement , such as concrete, deflects slightly un der a load and distribut es it over

a large area while bridging small weak spots in the base.

A surface r etains and waterproofs a load-bearing course. Bituminous sur face treat ments andmembran es a re usua l ly l es s th an 1 inch t h i ck a nd do no t con t r ibu te to the load -bea r ingcapacity of a base.


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Bituminous Materials 1-1

PART ONEBituminous Pavements and Surfaces

Bituminous pavements and surfaces are composed of compacted aggregate andbitumen. The aggregate transmits the load from the surface to the base, takes theabrasive wear of traffic, and provides a nonskid surface. The bitumen (bituminousbinder) holds the aggregate together, prevents the displacement and loss ofaggregate, and provides a waterproof cover for the base.

Bituminous surfaces

Are particularly adaptable to stage construction because engineers can addcourses to existing pavement for reinforcement if the load or the amount oftraffic increases.

Are flexible, allowing for slight adjustments due to subgrade settlement withoutdetrimental effects.

Provide a resilient, waterproof medium that protects the base from water andtraffic.

Are less affected by temperature changes than concrete. Resist wear, weathering, and deterioration. Are highly versatile and meet temporary, expedient, and light traffic

requirements where concrete is unjustifiable. Lack measurable beam action to carry loads over weak spots in the subbase.

(The subbase must have an adequate, uniform bearing strength; and the basemust have adequate thickness, bearing capacity, and cohesion.)

Bituminous pavements are comparable to concrete pavements and are designed tocarry heavy traffic volume and heavy loads on highways, roads, streets, and airfields.

Chapter 1

Bituminous Materials

Aspha l t pavemen t s a r e composed o f a spha l t and agg rega t e . Aspha l t -

concrete pavement is the highest quality asphalt pavement. It consists of w e ll -g r a d e d a g g r e ga t e a n d a s p h a l t ce m e n t (AC ) t h a t a r e h e a t e d a n dblended together in exact proportions at a hot-mix plant.


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1-2 Bituminous Materials

TYPES OF BITUMEN

1-1. Asphalt and tar bitumens are used in road and airfield construction. (SeeFM 5-472 for field identification of tar and asphalt paving compounds.)

ASPHALT

1-2. Asphalt is a natural or man-made by-product of petroleum disti l lation.Natu ral a sphalt is found in nat ure, either as lake (pit) or rock asph alt:

Lake asphal t . It is formed when crude oil seeps to the surface of the

earth and lighter fractions (volati le materials) are driven off by thea c t i o n o f s u n a n d w i n d . L a rg e d e p o s i t s o f l a k e a s p h a l t e x i s t i nTrinidad and Venezuela.

Rock a spha l t . I t occurs in more than one form. I t may be asphal tt h a t i s i m p r e gn a t e d i n p or o u s r o ck s , or i t m a y b e a s p h a l t t h a t i sha rdened into r ock-like form s.

1-3 . Manufactured asphal t i s more uniform in qual ity th an natu ra l asphal t .AC is the residue (waste product) of crude-oil distillation. It is used alone or incombination with other materials to form asphalt cutbacks and emulsions. Allthree bituminous compounds (lake, rock, and manufactured) are referred to asaspha l t . Use na tu ra l a spha l t when i t i s l oca l ly ava i l ab le ; o the rwise , u semanufactured asphalt .

TAR

1-4. Tar is extr acted from coal. Coal-gas t ar is a by-product of coke production,and water-gas tar is distilled from tar vapors. Both are produced, condensed,an d collected during t he pr oduction of illum inat ing gas an d ar e used in pa vingta r. Wate r-gas t a r combines wi th coa l -gas t a r a s a f lux . The two types o f paving tar are road tar (RT) and road-tar cutback (RTCB).

ASPH ALT CEMENT

1-5. AC consistency varies in relation to the amount of volatile substances inthe r esidue. The penetration (hardness) test measures the distan ce in u nits of

1/100 centimeter that a standard blunt needle of a penetrometer, under a forceof 100 grams, wi l l penetra te an AC sample a t 77F in 5 seconds . (See FM 5-472 for more details on the penetration test.)

1 -6 . The re a re n ine pav ing g rades o f AC. Each g rade i s des igna ted by apenetration-grade number, an asphalt-petroleum (AP) number, and a relative-consisten cy (ha rdn ess) indicat or (ha rd, medium , or s oft). (See Table 1-1. )

SECTION I - BITUMEN


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ASPH ALT CUTB ACK

1-7. Asphalt cutback is produced during th e refining process or from heat edAC that i s cut back wi th a vola t i le pet roleum dis t i l la te (cut ter s tock) . Incontr as t to AC, asphal t cutback is workable a t low temperat ures . Napht ha ,gasoline, kerosene, jet fuel, diesel oil, and fuel oil can be used as cutter stocks.The three types of asphalt cutback are based on the rate of curing:

Slow-cur ing (SC) asphal t cutback. It contains diesel oil or fuel oil. Medium-cur ing (MC) asphal t cutback. It contains a less volatile

substance, such as kerosene or jet fuel. Rap id -cu r ing (RC) a spha l t cu tback . It conta ins a highly volati le

cutter stock that evaporates rapidly, such as naphtha or gasoline.

1-8. The viscosity (resistance to flow) of asphalt cutback varies according tothe amount of cutter stock added and the type of AC used. As the amount of cut ter stock increases, t he viscosity decreases. Ea ch type of asphalt cut back isproduced in four standard grades of kinematic viscosity70, 250, 800, and3,000 centistokes. The n umer ical gra de is t he lowest k inemat ic viscosity limitat 140F, an d th e upper limit is twice th e lower limit. Therefore, RC-250 has akinema tic viscosity ra nge of 250 t o 500 centistokes a t 140F.

ASPHALT EMULSION1-9. Asphalt emulsion is a nonflamma ble liquid substan ce tha t is produced bycombining asphalt and water with an emulsifying agent such as soap, dust, orcertain colloidal clays. The emulsifying agent promotes emulsification andcontrols cert ain physical pr operties of the emu lsion. Emu lsion is deposited ona sur face; and when th e water a nd a sphalt break (separa te), they leave a th infilm of AC.

Table 1-1. Paving Grades of AC

PenetrationGrade AP

RelativeConsistency

40-50 7 Hard

50-60* 6 Hard

60-70 5 Hard

70-80* 4 Hard

85-100 3 Medium

100-120* 2 Medium

120-150 1 Medium

150-200* 0 Soft

200-300 00 Soft

*Penetration grade is no longer readily available. It isprovided to facilitate field identification if necessary.


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1-10. The two kinds of emuls ionsanionic and cat ionicare es tabl ishedaccording to t heir electr ical cha rge. The use of anionic (negatively char ged)emulsion is restricted because it does not adhere easily to negatively charged

siliceous aggregates. However, certain cationic (positively charged) emulsionsimprove a dherence t o negat ively charged a ggregates . In addi t ion, ca t ionicemulsions coat damp aggregates better than anionic emulsions.

1 -11 . The t h ree bas i c types o f emuls ions a r e r a p id se t t i ng (RS), med iumse t t ing (MS), an d s low se t t i ng (SS). The se t t i ng r a t e , wh ich i s t he r a t e o f asphalt and water separation, depends on the amount and kind of emulsifyingagent used. Asphalt emulsion is graded on the basis of viscosity and groupedaccording to its use. (See Table 1-2 .)

1 -12 . Emuls ions a re nonf l ammable and l iqu id a t o rd ina ry t empera tu res .Using water in an emulsion is a disadvantage in freezing weather because thewater freezes and break s th e emulsion. Emu lsions ar e also difficult t o store orstockpile since they tend to break while still in unopened drums. Due to thesedisadvantages, emulsions are not used extensively in the theater of operations(TO).

TAR

1 -1 3 . RT i s m a n u f a c t u r e d i n 1 2 g r a d e s o f v i s co s it y ( h a r d n e s s ) a t atemperat ure of 77F. Grades 1 t hrough 7 a re l iquid, and gra des 8 th rough 12are semisolid to solid. Liquid RT contains more l iquid coal disti l lates thansolid RT.

1 - 1 4 . RT i s r e d u c e d w i t h a c o a l - t a r d i s t i l l a t e t o f o r m RT C B , w h i c h i smanufactured only in viscosity grades 5 and 6. Highly volatile coal distillate,such as benzene or a solution of naph tha lene and benzol, is used to cut back the heavy grades of RT to produce RTCB. RTCB is similar to asphalt cutback

an d cures r apidly. The viscosity gra des of RT an d RTCB ar e compa ra ble to thev i s co s it y g r a d e s o f a s p h a l t cu t b a c k a n d A C. ( S e e F M 5 - 4 7 2 f o r m o r einformation.)

Table 1-2. Asphalt Emulsions

Emulsion Type Viscosity Grade Mixing Ability

AnionicRS RS-1, RS-2 SprayingMS MS-2 Mixing and sprayingSS SS-1, SS-1H Mixing and spraying

Cationic

RS-C RS-2C, RS-3C Spraying

MS-C MS-C Mixing (sand) and sprayingSS-C SS-C, SS-CH Mixing and spraying


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FUNCTION

1-15. Aggregate i s combined wi th b i tumen to form a bi tuminous wear ingsurface. This nonskid surface transm its th e load from th e surface to the baseand takes the abras ive wear of the t raffic. Aggregate consis ts of a minera lfiller a nd cru shed st one, gravel, sand, s lag, coral, or s imilar mat erial.

TYPES OF AGGREGATE

1-16 . For b i tuminous cons t ruc t ion , aggrega te i s c l a s s i f i ed accord ing topa r t i c l e s i z e . Th e s i z e o f a gg r ega t e u se d va r i e s w i t h cons t r u c t i onrequ i remen t s , and g rada t ion pa r t i c l e s l a rge ly de te rmine the mechan ica lstabil ity of a bitu minous mix. Some types of bitum inous sur faces require a naggregate gradat ion wi th a wide range of par t ic le s izes , whi le o ther typesrequire a uniform gradation of particles that are the same size. Particle size isdetermined by sor t ing the m ater ia ls on s ta ndar d s ieves . (See FM 5-472 forsieve an alysis.) The t hr ee types of aggregate ar e

Coarse aggregate (CA). It consists of crushed rock, broken gravel,slag, or other minera l materials tha t a re reta ined on a num ber 8 sieve.

Fine aggregate (FA). It consists of sand or small pieces of crushedrock tha t pass t hrough a num ber 8 sieve but ar e retained on a num ber200 sieve.

Mineral f i lle r. I t consis ts of iner t , nonplas t ic par t icles that pass

through a number 200 sieve. Rock dust, hydrated lime, inert fine soil,and portland cement can be used as mineral fillers. Most clays are tooplastic for th is pur pose.

1-17. These three types of aggregate are blended in different proportions toproduce various aggregate gradations. Trial-and-error calculations determinethe percentage (blend) of each s tockpi led aggregate used in the mix. Thefollowing aggregate gra dat ions are used in bituminous constru ction:

Uniform gradat ion. It consists of same-size aggregate particles thatare


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CHARACTERISTICS

1-18 . The in t e r lock ing a ggrega te ac t ion in a b i tuminous su r face i s morepronounced when angular, rough-textured particles are used, because angularparticles need more asphalt for coating than round particles. Using as mucha s p h a l t a s p os s i bl e i n a b i t u m i n o u s s u r f a c e e n s u r e s d u r a b i li t y w it h o u ti m p a i r i n g s t a b i l it y. A gg r e g a t e m u s t b e s t r o n g a n d d u r a b l e t o r e s i s tw e a t h e r i n g a n d m u s t h o l d u p u n d e r a p p l i e d l o a d s w i t h o u t c r a c k i n g o rb reak ing . (See FM 5-472 f o r t e s t s t o d e t e r m i n e a g g r e g a t e s t r e n g t h a n ddurability.)

1 -1 9 . Ag gr e g a t e p a r t i cl e s m u s t b e c le a n a n d d r y s o t h a t b i t u m e n ca np e n e t r a t e t h e p o r e s a n d h o ld t h e p a r t i c le s t o ge t h e r. B it u m e n w i l l n otpenetrate or adhere if aggregate is coated with clay or dust or if the pores arewet. In addition, aggregate must be hot and dry for hot mixes. The moisturecontent should be


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Bituminous Design 2-1

Chapter 2Bituminous Design

B i t u m i n o u s d e s i gn con s i s t s o f s e l ec t i n g t h e b i t u m e n a n d a g gr e g a t egrada tion, blending the aggregates t o conform to the selected gradat ion,determining the optimum content , and calculat ing the job-mix formula(J MF). After determining t he percenta ges of mater ials, calculat e th e totalquan t i t y o f ma t e r i a l s needed for t he p ro ject . Th i s chap te r de t a i l s t hedesign of a typical high mix. Low mixes are designed by the same method,al though m an y steps ar e often omitted becau se th e al lowable var iat ionsare great enough th at accurat e measurements are unnecessary.

BITUMEN SELECTION

2-1. The selection of a particular bituminous material depends on the type of pavement , the range of temperatures , the amount of ra infa l l , the type andvolume of tra ffic, and th e type an d ava ilability of equipment. In general, ha rd-penetra t ion grades of AC are used in warm cl imates and sof t -penetra t iongrades are used in cold climates. Heavy grades of asphalt cutback and tar arenormally used in warm regions, and light grades are used in cool regions. ACis generally more su itable for high t raffic volume tha n cutba ck. Asphalt andta r do no t necessa r i ly bond to each o the r ; t hus , bond ing a l so becomes aconsidera tion in bitu men selection. Tables 2-1 an d 2-2 , pages 2-2 thr ough 2-4,

list the characteristics and uses of bituminous materials.ASPHALT CEMENT

2-2. AC is us ually used in hot-mix pavement s a nd is solid at 77F. To ma keAC f lu id enough fo r mix ing wi th aggrega te o r fo r sp ray ing , hea t i t t o atemperatu re of 250 to 350F. A disadvantage of AC is tha t adequat e hea tingequipment may not always be available. The various penetration grades of ACare suitable for plant mixes, penetra tion macadams, an d sur face treatment s.

ASP HALT CUTBACK

2-3. Different types and grades of aspha l t cutback a re u sed dur ing var iouscl imat ic condi t ions . When the cut ter s tock evaporates , i t leaves AC as anactive bonding and waterproofing agent. Consider the prevailing atmospherictemperature during construction when selecting the grade of asphalt cutback.Light grades are usually used in cool weather. If the preferred grade and typeof asphalt cutback is unavailable, use a comparable grade of another type. Forexample, using RC-70 instea d of MC-70 or using RC-300 instea d of MC-300will not ser iously affect the fin ished s t r uctur e . In the fie ld , l ight grades of asphalt cutback can be made by adding solvents to AC or to heavier grades of asph alt cutba ck. (See Chapter 5 for m ore informat ion on t he field ma nu factur eof asph alt cut backs.)


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2-2 Bituminous Design

T a b l e 2 - 1 . C h a r a c t e r i s t i c s o f B i t u m i n o u s M a t e r i a l s

M a t e r i a l

F o r m

G r a d e

D e s i g n a -

t i o n

T e m p e r a t u r e o f A p p l i c a t i o n R a n g e s

F l a s h P o i n t

R e m a r k s

S p r a y i n g 1

M i x i n g

F

C

F

C

F

C

P e n e t r a t i v e s o i l

b i n d e r

L i q u i d

1 3 0 - 1 5 0

5 5 - 6

5

8 0

2 7 C o n t a i n s n a p h t h a .

C a u t i o n : H i g h l y f l a m m a b l e .

C u t b a c k ( R C )

L i q u i d a s p h a l t

r e s i d u e s f l u x e d

w i t h m o r e v o l a t i l e

p e t r o l e u m d i s t i l l a t e

R C - 7

0

R C - 2

5 0

R C - 8

0 0

R C - 3 , 0

0 0

1 0 5 - 1 7 5 2

1 4 5 - 2 2 0

1 8 0 - 2 5 5

2 1 5 - 2 9 0 2

4 1 - 7

9 2

6 3 - 1

0 4

8 2 - 1

2 4 2

1 0 2 - 1 4 3 2

9 5 - 1

3 5

1 3 5 - 1 7 5

1 7 0 - 2 1 0

2 0 0 - 2 4 0

3 5 - 5

7

5 7 - 7

9

7 7 - 9

9

9 3 - 1

1 6

8 0 8 0 8 0

2 7 2 7 2 7 R C c u t b a c k s c o n t a i n h i g h l y

v o l a t i l e n a p h t h a c u t t e r s t o c k .

N a p h t h a e v a p o r a t e s q u i c k l y ,

l e a v i n g a n A C b i n d e r a n d

p e r m i t t i n g e a r l y u s e o f t h e

s u r f a c e .

C a u t i o n : H i g h l y f l a m m a b l e .

C u t b a c k ( M C )





M C - 3

0

M C - 7

0

M C - 2

5 0

M C - 8

0 0

M C - 3 , 0

0 0

7 0 - 1 4 0

1 0 5 - 1 7 5

1 4 5 - 2 2 0

1 8 0 - 2 5 5

2 1 5 - 2 9 0

2 1 - 6

0

4 1 - 7

9

6 3 - 1

0 4

8 2 - 1

2 4

1 0 2 - 1 4 3

5 5 - 9

5

9 5 - 1

3 5

1 3 5 - 1 7 5

1 7 0 - 2 1 0

2 0 0 - 2 4 0

1 3 - 3

5

3 5 - 5

7

5 7 - 7

9

7 7 - 9

9

9 3 - 1

1 6

1 0 0

1 0 0

1 5 0

1 5 0

1 5 0

3 7 3 7 6 5 6 5 6 5 M C c u t b a c k s c o n t a i n l e s s

v o l a t i l e k e r o s e n e c u t t e r

s t o c k . K e r o s e n e e v a p o r a t e s

l e s s r a p i d l y t h a n n a p h t h a

.

C a u t i o n : F l a m m a b l e

.

C u t b a c k ( S C )





S C - 7

0

S C - 2

5 0

S C - 8

0 0

S C - 3 , 0

0 0

1 0 5 - 1 7 5

1 4 5 - 2 2 0

1 8 0 - 2 2 5

2 1 5 - 2 9 0

4 1 - 7

9

6 3 - 1

0 4

8 2 - 1

2 4

1 0 2 - 1 4 3

9 5 - 1

3 5

1 3 5 - 1 7 5

1 7 0 - 2 1 0

2 0 0 - 2 4 0

3 5 - 5

7

5 7 - 7

9

7 1 - 9

9

9 3 - 1

1 6

1 5 0

1 7 5 +

2 0 0 +

2 2 5 +

6 5 7 9 +

9 3 +

1 0 7 +

S C c u t b a c k s c o n t a i n s l i g h t l y

v o l a t i l e d i e s e l - f u e l c u t t e r

s t o c k . D i e s e l f u e l e v a p o r a t e s

s l o w l y .


.

A C

S o l i d

4 0 - 5

0

6 0 - 7

0

8 5 - 1

0 0

1 2 0 - 1 5 0

2 0 0 - 3 0 0

2 8 5 - 3 5 0

2 8 5 - 3 5 0

2 8 5 - 3 5 0

2 6 0 - 3 2 5

1 4 1 - 1 7 7

1 4 1 - 1 7 7

1 4 1 - 1 7 7

1 2 7 - 1 6 3

3 0 0 - 3 5 0

2 7 5 - 3 2 5

2 7 5 - 3 2 5

2 7 5 - 3 2 5

2 0 0 - 2 7 5

1 4 9 - 1 7 7

1 3 5 - 1 6 3

1 3 5 - 1 6 3

1 3 5 - 1 6 3

9 3 - 1

3 5

P e n e t r a t i o n s 4 0 t o 1 0 0 a r e

u s e d f o r c r a c k a n d j o i n t

f i l l e r s . P

e n e t r a t i o n s 7 0 t o

3 0 0 a r e u s e d f o r p l a n t

m i x e s , p

e n e t r a t i o n

m a c a d a m , a

n d s u r f a c e

t r e a t m e n t . T e s t t o d e t e r m i n e

t h e f l a s h p o i n t .

P o w d e r e d a s p h a l t

H a r d a n d s o l i d

a s p h a l t g r o u n d t o

p o w d e r

U s e d w i t h S C t o p r o d u c e

e x t r a t o u g h r o a d s u r f a c e s .

1 L o w t e m p e r a t u r e i s b a s e d o n a 2 0 0 - c e n t i s t o k e k i n e m a t i c v i s c o s i t y

, a n d t h e h i g h t e m p e r a t u r e i s b a s e d o n a 5 0 - c e n t i s t o k e v i s c o s i t y

.

2 R C c u t b a c k s a r e s e l d o m u s e d f o r s p r a y i n g .


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FM 5-436


T a b l e 2 - 1 . C h a r a c t e r i s t i c s o f B i t u m i n o u s M a t e r i a l s ( c o n t i n u e d )

M a t e r i a l

F o r m

G r a d e

D e s i g -

n a t i o n

T e m p e r a t u r e o f A p p l i c a t i o n R a n g e s

F l a s h P o i n t

R e m a r k s

S p r a y i n g 1

M i x i n g

F

C

F

C

F

C

A s p h a l t e m u l s i o n

( R S )

L i q u i d ( a s p h a l t

p a r t i c l e s h e l d i n

a n a q u e o u s

s u s p e n s i o n b y a n

e m u l s i f y i n g

a g e n t )

R S - 1

R S - 2

R S - 2

K

R S - 3

K

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0 1 0 - 6 0

1 0 - 6 0

1 0 - 6 0

1 0 - 6 0

N o n m i x i n g

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

1 0 - 6

0

1 0 - 6

0

1 0 - 6

0

1 0 - 6

0

F r e e z i n g d e s t r o y s e m u l s i o n s .

U s e d f o r r o a d a n d p l a n t m i x e s

w i t h C A ( S S ) . A l l e m u l s i o n s

w i t h K s u f f i x a r e c a t i o n i c .


( M S )



a n a q u e o u s



a g e n t )

M S - 2

S M - K

C M - K

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0 1 0 - 6 0

1 0 - 6 0

1 0 - 6 0

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

1 0 - 6

0

1 0 - 6

0

1 0 - 6

0


( S S )



a n a q u e o u s



a g e n t )

S S - 1

S S - 1

H

S S - K

S S - K

H

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0 1 0 - 6 0

1 0 - 6 0

1 0 - 6 0

1 0 - 6 0

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

5 0 - 1

4 0

1 0 - 6

0

1 0 - 6

0

1 0 - 6

0

1 0 - 6

0

R T

L i q u i d

R T - 1

R T - 2

R T - 3

6 0 - 1

2 5

6 0 - 1

2 5

6 0 - 1

2 5 1 5 - 5 2

1 5 - 5 2

2 7 - 6 6

P r i m i n g o i l s

. R T - 4 t h r o u g h

R T - 1 2 a r e n o t g e n e r a l l y u s e d .

R T C B

L i q u i d

R T C B - 5

R T C B - 6

6 0 - 1

2 0

6 0 - 1

2 0 1 6 - 4 9

1 6 - 4 9

P a t c h i n g m i x t u r e s .


.

R o c k a s p h a l t

S o l i d

M i x e d a n d u s e d l o c a l l y w h e r e

f o u n d . C u t b a c k m a y b e a d d e d

i f n e c e s s a r y .

1 L o w t e m p e r a t u r e i s b a s e d o n a 2 0 0 - c e n t i s t o k e k i n e m a t i c v i s c o s i t y

, a n d t h e h i g h t e m p e r a t u r e i s b a s e d o n a 5 0 - c e n t i s t o k e v i s c o s i t y

.

2 R C c u t b a c k s a r e s e l d o m u s e d f o r s p r a y i n g .


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Table 2-2. Typical Uses of Bituminous Materials

Purpose or Use Grade or Designation 1 of Asphalt Cutback 2RC MC SC

Dust palliative DCA-70 3MC-30, -70, -250APSB

SC-70, -250

Prime coat:Tightly bonded surfacesLoosely bonded, fine-grained surfacesLoosely bonded, coarse-grained

surfaces

MC-30MC-70MC-250

SC-70SC-250

Tack coat RC-250, -800 MC-250, -800Surface treatment and seal coat:

Coarse sand coverClean CA cover

Graded gravel aggregate coverGravel mulch

RC-70, -250RC-250, -800,-3,000

MC-250, -800MC-800

MC-250-, -800MC-250 SC-800SC-250Mixed-in-place road mix:

Open-graded aggregate:SandMaximum diameter 1 inch, high

percentage passing No. 10

RC-70, -250 MC-800MC-800

Macadam aggregate RC-250, -800Dense-graded aggregate:

High percentage passing No. 200Maximum diameter 1 inch, medium

percentage passing No. 200

MC-250MC-250, -800

SC-250SC-250, -800

Premix or cold patch:Open-graded aggregateDense-graded aggregate

RC-250 MC-800MC-250

SC-800SC-250

Cold-laid plant mix:Open-graded aggregate:

SandMaximum diameter 1 inch, highpercentage passing No. 10

Macadam aggregateDense-graded aggregate:

High percentage passing No. 200Maximum diameter 1 inch, medium

percentage passing No. 200Aggregate precoating followed with

asphalt

RC-250, -800RC-800

RC-800, -3,000

SC-800

Hot-laid plant mix RC-3,000 MC-3,000 SC-3,000Penetration macadam:

Cold weatherHot weather

RC-800, -3,000 SC-3,000

1Prevailing temperature during construction also affects selection of bitumen and may be thedetermining factor rather than size and gradation of aggregate.2Caution: Do not overheat aggregate when cutbacks are used to produce hot mixes.3DCA-70 is a water emulsion of a polyvinyl acetate containing chemical modifiers (formerly UCAR-131). Proprietary product of Union Carbide Corporation, New York, NY.


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FM 5-436


ASPHALT EMULSION

2-4 . The m ixing g rades o f a sph a l t emu l s ion can be combined wi th da mpaggregate wi th l i t t le or no heat ing. The recommended use depends on the

setting r at e an d th e mixing ability. Use emulsions for surface treat ment s, roadan d plant mixes, an d crack an d joint fillings.

TAR

2-5. Since tar does not dissolve in petroleum distillates, use it in areas whereasphalt is unsuitable, such as refueling aprons at airfields where petroleumd i s t i ll a t e s a r e l i k e ly t o b e s p i ll e d. B e ca u s e t a r h a s g r e a t e r p e n e t r a t i n gqualities than asphalt, it is preferred when penetration is critical. Use hot tarfor plant mixes, surface treatments, penetration macadams, and crack fillers.Use RTCB for patch m ixes , surface t r ea tments , a nd road mixes. Do not u seo p en f l a m e s n e a r s t or a g e t a n k s o r d r u m s o f RTC B b e ca u s e i t i s h i g h l yflammable. Tar is m ore susceptible to temperat ure chan ges th an asphalt , an d

tar becomes soft a t high temperatu res an d brit t le at low temperat ures.

AGGREGATE S ELECTION

2 - 6 . B e f o r e i n c l u d i n g s p e c i f i c a g g r e g a t e i n a m i x d e s i g n , c o n d u c t ap r e l im i n a r y i n v e s t i ga t i on of t h e a g gr e g a t e a n d e n s u r e t h a t i t s p h y s i ca lproperties conform to those described in Chapter 1 . In addi t ion, perform acomplete an alysis of the aggregate a s described in FM 5-472 and determinethe qua ntity of aggregate available. Select the grada tion specification u singthe criteria in Table 2-3 , pages 2-6 thr ough 2-9.

MIX GRADATION

2-7. Aggregates and minera l f i l le rs can be combined to produce a dense-graded or an open-graded mix:

D e n s e -g r a de d m i x . A dense-graded mix conta ins a cont inuousgradat ion of part icle sizes th at are coarse to very fine. Fine part iclesfi ll th e voids between lar ge par t icles , thereby in creas in g th e m ixsweight. A dense-graded mix is more impervious to water and providesmore protection to the base an d t he su bgrade. I t usua lly requires lessmaintenance, and the asphal t l i fe i s prolonged. However, a dense-graded mix requires precise determination and control of the bitumen-aggregate ratio.

Open-graded mix. An open-graded mix also contains coar se an d finepa r t i cl e s in a con t inu ous g rada t ion . H owever, i t does n ot con ta in

enough fine pa rticles t o fi l l the voids between large pa rticles so i t isless dense. Because of the increased voids in an open-graded mix, thebitumen-aggregate rat io is less critical.


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FM 5-436


T a b l e 2 - 3 . G r a d a t i o n S p e c i f i c a t i o n L i m i t s f o r B i t u m i n o u s C

o n s t r u c t i o n

S i e v e

D e s i g n a -

t i o n

P e r c e n t a g e P a s s i n g b y W e i g h t

M a x i m u m P a r t i c l e S i z e

2 I n c h

1 1 / 2 I n c h

1 I n c h

3 / 4 I n c h

1 / 2 I n c h

1 / 4 I n c h

P a v e m e n t s

, P l a n t M i x e s

( S q u a r e

O p e n i n g s )

A s p h a l t M i x t u r e , S

u r f a c e C o u r s e , L o w - P r e s s u r e T i r e s ( 1 0 0 p s i a n d U n d e r )

G r a d a t i o n 1

G r a d a t i o n 2

G r a d a t i o n 3

G r a d a t i o n 4

G r a d a t i o n 5

A

B

C

A

B

C

A

B

C

A

B

C

A

B

C

1 1 / 2 i n c h

1 0 0

1 0 0

1 0 0

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

1 i n c h

7 9 - 9

5 8 3 - 9

6

8 6 - 9 8

1 0 0

1 0 0

1 0 0

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

- - -

3 / 4 i n c h

7 0 - 8

4 7 4 - 8

6 7 8 - 9 0

8 0 - 9

5 8 4 - 9

6 9 0 - 9

8 1 0 0

1 0 0

1 0 0

- - -

- - -

- - -

- - -

- - -

- - -

1 / 2 i n c h

6 1 - 7

5 6 6 - 7

9

7 1 - 8 4

6 8 - 8

6 7 4 - 8

9 7 9 - 9

3 8 0 - 9

5 8 4 - 9

6 8 7 - 9

8 1 0 0

1 0 0

1 0 0

- - -

- - -

- - -

3 / 8 i n c h

5 4 - 6

8 6 0 - 7

2

6 5 - 7 8

6 0 - 7

7 6 6 - 8

2 7 2 - 8

7 7 2 - 8

6 7 6 - 8

8 8 0 - 9

2 7 9 - 9

4 8 1 - 9

5 8 5 - 9

6 1 0 0

1 0 0

army - fm5 436 - paving and surfacing operations

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