6-7 binder ( Highway Engineering Dr. Sherif El-Badawy )

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Mansoura University - Faculty of Engineering – Public Works Engineering Dept.

Types & Uses of Asphalt Materials

HMA Surface

Dr. Sherif El-Badawy Mansoura University - Faculty of Engineering – Public Works Engineering Dept.

+

HMA (Hot Mix Asphalt)


Bituminous Materials

Asphalt Tar

Asphalt

Cement Emulsion Cutback

(from petroleum crude) (from coal)

Natural

Asphalt

Petroleum

Asphalt

Oxidized

Asphalt


Trinidad Lake Asphalt

Natural bitumen from the Dead Sea, Wiki

2


Asphalt Binder is

Generally Produced

in a Refinery

Oil is produced in mainly 4 regions: Middle East, Russia,

United States, and Central America



General Asphalt Binder Properties

• Adheres well to most rock

• Waterproof

• Fairly durable

• Resistant to reaction with most acids,

alkalis, and salts

• Temperature sensitive


Asphalt Components Asphalt binder is broken down into 3 components:

• Asphaltenes • Dark brown friable solids

• Control viscosity and adhesive properties

• Resins • Dark solid or semi-solid

• Greatly affected by temp.

• Disperse the asphaltenes

• Oils • Colorless or white liquids

• Oxidize and harden into asphaltenes and resin molecules

* These three components are Blended to produce

asphalt binder of desired properties

3


Asphalt Types Used in Pavement

• Asphalt cement (asphalt binder)

Used for HMA, patching

• Asphalt emulsion

(residue + water + emulsifying agent)

• Asphalt cutback

(residue + solvent)


Emulsions and Cutbacks

• Asphalt Emulsion

• (30-40%residue +60-70% water + fraction

of a % of emulsifying agent)

• Used for cold mix maintenance, patching, chip

seals, slurry seals, crack sealing, base and sub-

base stabilization, and surfacing low volume

roads

• Asphalt Cutback (residue + solvent)

• Hazardous, volatile solvents and hydrocarbons

are released

• Same as emulsion but phased out because of

environmental reasons and cost


• Asphalt concrete

• Asphalt paving mix

• Asphalt mix

• Asphalt

Hot Mix Asphalt (HMA)

• Bituminous concrete

• Bituminous paving mix

• Bituminous mix

HMA = Asphalt concrete = binder + aggregate

Used mainly for hot mix pavement surfacing


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Mansoura University - Faculty of Engineering – Public Works Engineering Dept. Mansoura University - Faculty of Engineering – Public Works Engineering Dept.


Cutback Asphalts

Rapid Curing

(RC) Asphalt + Naphtha

Surface Treatment

RC - 70

RC - 250

RC - 800

RC - 3000

Medium Curing (MC)

Asphalt + Kerosene

Prime Coat

MC - 70

MC - 250

MC - 800

MC - 3000

Slow Curing (SC)

Asphalt + Oil

SC - 70

SC - 250

SC - 800

SC - 3000


70 250 800 3000

COMPOSITION OF CUTBACK ASPHALTS

RC = Naphtha; MC = Kerosene SC = Light Oil

Numbers represent the minimum kinematic viscosity in

centistokes at 60 oC

5


CUTBACKS - USES

• Rapid Curing

• Tack coats

• Surface treatments

• Medium curing

• Prime coats

• Stockpile patching materials

• Slow curing

• Prime Coats

• Stockpiling

Mansoura University - Faculty of Engineering – Public Works Engineering Dept. Asphalt

Binder

Types and Uses 20

EMULSIONS - USES

• Slow Setting (SS)

• Tack coats, fog seals, dense-graded cold mixes

• Medium Setting (MS)

• Open graded cold asphalt-aggregate mixtures

• Rapid Setting

• Surface treatments


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Properties of Asphalt Binder


Binder Performance is affected

by:

• Temperature

• Rate of Loading

• Aging


Temperature Susceptibility

Temperature, °C

Stiffness (Response to Load)

-30 25 60 135

elastic

viscous

elasticsolid

viscousfluid

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Log Temperature

Too brittle (Thermal cracking)

Too soft (Rutting)

Optimum range

Of viscosity

Lo

g L

og

(V

isco

sity

)



Log Temperature

Soft

Log L

og (

Vis

cosi

ty)

Hard

Soft asphalt is used in cold climates Hard asphalt is used in hot climates


Effect of Rate of Loading


60 C

25 C

1 hour

1 hour

Time vs. Temperature

10 hours

8


Aging Behavior

• Causes

Oxidation

Volatilization

Physical hardening

• Types

Short-term aging

Long-term aging


Modified Asphalt

Asphalt properties can be improved with

polymer and other modifiers

Temperature susceptibility

Adhesion to aggregates

Resistance to permanent deformation

Resistance to fatigue cracking

Elasticity, ductility, and durability


Traditional Tests: 1 Penetration test

2 Ring and Ball Softening Point test

3 Absolute Viscosity test

4 Kinematic Viscosity test

Performance Grade (Superpave) tests: 1 Rotational Viscometer (Brookfield) test

2 Dynamic Shear Rheometer (DSR) test

3 Bending Beam Rheometer (BBR) test

4 Direct Tension (DT) test

5 Rolling Thin Film Oven (RTFO) test

6 Pressure Aging Vessel (PAV) test

7 Flash Point test

Characterization of Asphalt Binder


Classification of Asphalt Cement

• Based on penetration

• Based on viscosity

• Based on viscosity after aging

• Based on performance (Superpave)

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Penetration Specifications


Penetration Test

100g100g

penetration

0 sec 5 sec


Penetration Specification

Five Grades

• 40 - 50

• 60 - 70

• 85 - 100

• 120 - 150

• 200 - 300 Maximum penetration

Minimum penetration Mansoura University - Faculty of Engineering – Public Works Engineering Dept.

Penetration Gradation Specification

• Uses penetration results to specify

• Adds

– Flash point test

– Ductility

– Solubility

– Thin film oven aging

• Penetration

• Ductility

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Flash Point (Safety)

Thermometer

Cup filled with

asphalt binder

Wand attached

to gas line


Ductility


Solubility (Purity)


Thin Film Oven

Outside of Oven Rotating Shelf

Pan Thermometer

11


Typical Penetration Specifications

Penetration 40 - 50 200 - 300

Flash Point, oF 450+ 350+

Ductility, cm 100+ 100+

Solubility, % 99.0+ 99.0+

Retained Pen., % 55+ 37+

Ductility, cm NA 100+


Temperature

25C (77F)

High

Medium

Low


Advantages of Penetration

Specifications

• Grades asphalt binders near average in-service

temp.

• Fast

• Can be used in field labs

• Low cost of Equipment

• Precision well established

• Temp. susceptibility can be determined


Disadvantages

• Empirical test

• Shear rate

– High

– Variable

• Mixing and compaction temperature information not

available

• Similar penetrations at 25C (77F) do not reflect wide

differences in asphalts

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Viscosity Graded Specifications


Viscosity: is defined as the resistance of the

material to flow.

Viscosity: is the ratio between the applied

shear stress and the rate of shear strain.

h = t / g

Definition


Units of Viscosity

• Pa.S = Pascal. Second

• cS = Centi Stoke

• cP = Centi Poise

• P = Poise

Pa.S = 1000 cP

P = 100 cP

Stoke = 100 cS

cS = cP * Gb


Viscosity Tests vacuum

CANNON

CANNON

100100

A9A9

Timing Marks

13


Absolute Viscosity Test

• Absolute viscosity

– U-shaped tube with

timing marks & filled

with asphalt binder

– Placed in 60C bath

– Vacuum used to pull

asphalt through tube

– Time to pass marks

– Visc. in Pa s (Poise)


Kinematic Viscosity Test

• Kinematic viscosity

– Cross arm tube with timing

marks & filled with asphalt

– Placed in 135C bath

– Once started gravity moves

asphalt through tube

– Time to pass marks

– Visc. in mm2 / s (centistoke)


Viscosity Grade Specifications

• Viscosities at 60 and 135oC

• Penetrations at 25oC

• Flash point

• Solubility

• TFO aged residue

– Viscosity at 60oC

– Ductility at 25oC


AC Grades (Viscosity Grades)

AC-2.5, AC-5, AC-10

AC-20, AC-30, AC-40

AC- # 1/100 of midpoint of the allowable viscosity range.

AC-20, viscosity range 1,600 to 2,400 poises.

Asphalt cement

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AC Grades Example

AC 2.5 AC 40

Visc, 60C 250 + 50 4,000 + 800

Visc, 135C 80+ 300+

Penetration 200+ 20+

Visc, 60C <1,250 <20,000

Ductility 100+ 10+

Log Temperature

25C (77F) 60C (140F) 135C (275F)

Ave.

Service

Temp.

Mixing

&

Compaction

Hot

Summer

Lo

g L

og

Vis

co

sit

y (

Sti

ffn

es

s)


Log Temperature, R

Log

Log

Vis

cosi

ty, cP

Compaction Range

Mixing Range

Mixing/Compaction Temps


Ai-VTSi

Temperature - Viscosity Relationship for:

PG 64-22, Tank Condition

y = -3.8785x + 11.519

R2 = 0.992

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2.70 2.75 2.80 2.85 2.90 2.95

Log (Temp) (R)

Log L

og (

Vis

c)

(cP

)

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Advantages of (Original AC Visc. Grade)

• Fundamental property

• Wide range of temperatures

• Based on max. pavement surface temp.

• Wide range of instruments

• Test method precision established

• Temperature susceptibility is controlled

• Limits aging

• Information on mixing & compaction temps.


Disadvantages

(Original AC Visc. Grade)

• More expensive

• Longer testing time

• More technician skill needed

• Not applicable for Non-Newtonian materials

• Wide range of properties for same grade


Viscosity After Aging Graded

Specifications


AR Grades

AR-10, AR-20, AR-40

AR-80, AR-160

AR- # 1/100 of midpoint of viscosity after aging.

AR-40, viscosity range 3,000 to 5,000 poises.

Aged residue

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AR Grades Specifications • AR Grades

– AR 1000, AR 2000, AR 4000,

AR 8000, AR 16000

• Tests on RTFO aged residue

– Viscosities at 60 and 135oC

– Penetrations at 25oC

– % of Original Penetration

– Ductility

– Properties of unaged asphalt

binders

• Flash point and solubility


Fan

Air Line

Rotating

Bottle

Carriage

Before After

Rolling Thin Film Oven Test (RTFOT)


Advantages

(AR Visc. Grade)

• Represents asphalt binder properties after

mixing

• Fundamental properties

• Covers wide range of temperatures

• Limits aging


Disadvantages

(AR Visc. Grade)

• Highly regional

• Requires different testing equipment

• Longer testing time

• No consistency test on original Asphalt Binder

• Not applicable for Non-Newtonian materials

• Wide range of properties for same grade

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40

50

60

70 85

100

120

150 200

300

Penetration Grades

AC 40

AC 20

AC 10

AC 5

AC 2.5

100

50

10

5

Vis

co

sit

y, 6

0C

(140F

) AR 16000

AR 8000

AR 4000

AR 2000

AR 1000

Comparison of the Various Traditional

Specifications


Traditional tests: 1 Penetration test

2 Ring and Ball Softening Point test

3 Absolute Viscosity test

4 Kinematic Viscosity test

Performance Grade (Superpave) tests: 1 Rotational Viscometer (Brookfield) test

2 Dynamic Shear Rheometer (DSR) test

3 Bending Beam Rheometer (BBR) test

4 Direct Tension (DT) test

5 Rolling Thin Film Oven (RTFO) test

6 Pressure Aging Vessel (PAV) test

7 Flash Point test

Characterization of Asphalt Binder


Superpave Asphalt Binder Specification


New Superpave Binder Specifications

Intended to improve pavement performance by

reducing the potential to:

Permanent deformation

Fatigue cracking

Low-temperature cracking

Excessive aging from volatilization

Pumping and handling

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Superpave Asphalt Binder Specification

PG 64-22

PerformanceGrade

Average 7-daymax pavementdesign temp

Min pavementdesign temp

Grading system and selection based primarily on climate

(NHI, 2002)


Pavement Temperatures are Calculated

• Calculated by Superpave software

• High temperature

– 20 mm below the surface of mixture

• Low temperature

– at surface of mixture

Pave temp = f (air temp, depth, latitude)

www.tfhrc.gov/pavement/ltpp/ltppbind.htm


PG Specification Tests

• Rheology

• Fundamental properties related to HMA performance

• Test parameters • Selected to represent in-service & construction

temperatures

• Asphalt binder conditioning • Environmental factors

• Short and long term aging


Test Equipment Performance Property

Rotational Viscometer

Dynamic Shear

Rheometer

Bending Beam Rheometer

Direct Tension

Tester

Handling Pumping

Permanent Deformation

Fatigue Cracking

Thermal Cracking

Flow

Rutting

Structural

Cracking

Low Temp.

Cracking

http://www.tfhrc.gov/pavement/ltpp/ltppbind.htm

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Superpave Binder Equipment

Fatigue

CrackingRutting

PAV - aging

RTFO - aging No aging

Pavement Age

Construction

[RV][DSR]

Low Temp

Cracking

[BBR]

[DTT]


Superpave Binder Equipment

Pavement Temperature, C

- 20 20 60 135

DTT

BBR

DSR

RV


Rotational Viscometer

spindle

torque

sample

sample

chamber

(Brookfield Viscosity)


RV

DSR

BBR

Rutting

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Short Term Aging

• Simulates stiffening of asphalt binder

during storage, mixing, and lay down

• Function of:

• Oxidation hardening

• Asphalt binder reacts with oxygen

• Volatilization of specific components

• Simulated using rolling thin film oven

(RTFO)


Dynamic Shear Rheometer

Applied Stress

Fixed Plate

Asphalt

Oscillating

Plate

B CA

Position of

Oscillating Plate

A

B

A

C

A

Time

1 cycle


Dynamic Shear Rheometer

height (h)

radius (r)

torque (T)

deflection angle ()


Elastic vs. Viscous Behaviors

time

time

Elastic: = 0 deg Viscous: = 90 deg

gmax

gmax

tmax tmax

time lag = t

Applied

Shear

Stress

Resulting

Shear

Strain

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Viscoelastic: 0 < < 90 o

Resulting

Shear

Strain

Applied

ShearStress

gmax

t t = time lag

time

time

tmax

tG* = gmax

max


Rutting

• High in-service temperature

• Desert climates

• Summer temperatures

• Sustained loads

• Slow moving trucks

• Intersections

Viscous Liquid

Function of warm

weather and traffic


Rutting Superpave DSR test requirements:

G*/sin on unaged (original) asphalt binder

> 1.00 kPa

G*/sin on RTFO aged asphalt binder

> 2.20 kPa

We want a stiff, elastic asphalt binder

to resist rutting (for the early part of the

service life)

(By increasing G* or decreasing )


RV

DSR

BBR

Fatigue

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Fatigue Cracking

Function of repeated traffic loads over time

(in wheel paths)


DSR

• Aged PG asphalt binder

• Since long term performance

problem, include:

• Short term aging

• Long term aging

• Determine DSR parameters using

8 mm plate and intermediate test

temperature

Fatigue

Cracking

[DSR]


Long Term Aging

• Simulates aging of an PG asphalt binder for 7

to 10 years

• Starts with RTFO aged PG asphalt binder

– Additional aging with Pressure Aging Vessel

(PAV)


PAV Components

Bottom of

pressure

aging

vessel

Rack of individual

pans

(50g of asphalt / pan)

Vessel Lid Components

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Fatigue Cracking

• G* (sin ) on RTFO and PAV aged asphalt

binder

• The parameter addresses the later part of the

fatigue life

• Value must be < 5,000 kPa

We want a soft elastic asphalt binder to

sustain many loads without cracking

(By decreasing G* or decreasing )



Fluid Bath

DeflectionTransducer

Load Cell

Asphalt Beam

Air Bearing

Loading

Frame

Supports

Control andData Acquisition

Thermometer





aluminum mold

plastic strips

Rubber O-rings

127 mm

6.35 mm

12.7 mm

asphalt beam

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RV DSR

BBR

Thermal

Cracking

Pavement Temperature, C

- 20 20 60 135

DTT

BBR

DSR

RV

DTT


Low Temperature Behavior

• Low Temperature

• Cold climates

• Winter

• Rapid Loads

• Fast moving trucks

Elastic Solid


Thermal Cracking

Courtesy of FHWA Mansoura University - Faculty of Engineering – Public Works Engineering Dept.

Low Temperature

• Two tests

• Bending beam

• Stiffness

• Direct tension

• Strength

Low Temp

Cracking

[BBR]

[DTT]

25


Direct Tension Tester

L

Load

L+ L

L

failure strain ( f) =

effective length (L )

change in length ( L)

eL

e

f

stress

strain

f


Summary

Fatigue

Cracking Rutting

RTFO

Short Term Aging No aging

Construction

[RV] [DSR]

Low Temp

Cracking

[BBR]

[DTT]

PAV

Long Term Aging


PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82

(Rotational Viscosity) RV

90 90 100 100 100 (110) 100 (110) 110 (110)

(Flash Point) FP

46 52 58 64 70 76 82

46 52 58 64 70 76 82

(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %

(Direct Tension) DT

(Bending Beam Rheometer) BBR Physical Hardening

28

-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22

-28 -34

Avg 7-day Max, oC

1-day Min, oC

(PRESSURE AGING VESSEL) PAV

ORIGINAL

> 1.00 kPa

< 5000 kPa

> 2.20 kPa

S < 300 MPa m > 0.300

Report Value

> 1.00 %

20 Hours, 2.07 MPa

10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31

(Dynamic Shear Rheometer) DSR G* sin

( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value

-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -

18 -24

-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12

-18 -24

Superpave Binder Specifications

(Dynamic Shear Rheometer) DSR G*/sin

(Dynamic Shear Rheometer) DSR G*/sin

< 3 Pa.s @ 135 oC

> 230 oC

CEC


Flash Point Temp. T48: Minimum. C

Performance Grade PG-52 PG-58

-10 -16 -22 -28 -34 -40 -46 -16 -22 -28

<52 <58

>-10 >-16 >-22 >-28 >-34 >-40 >-46 >-16 >-22 >-28

Average 7-day Maximum

Pavement Design Temp. C Minimum Pavement

Design Temperature.C

Original Binder

135 Viscosity, ASTM D 4402

Maximum, Pa - s (3000 cP)

Test Temp. C

Dynamic Shear, TP5:

G*/sin 8 , Minimum, 1.00 kPa

Test Temp @ 10 rad/sec. C

52 58

Spec Requirement Remains Constant Test Temperature Changes

230

Superpave Binder Specifications