Superpave 3

7/26/2019 Superpave 3

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Asphalt Concrete Mix

DesignSuperpave


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Superpave Volumetric Mix Design

GoalsCompaction method which simulates fieldAccommodates large size aggregates

Measure of compactibilityAble to use in field labsAddress durability issues

Film thickness Environmental


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SHRP Project 1988 199!

he !utcomes of the S"#$ $ro%ect&ew Asphalt Grading system '$G(

Consensus properties of aggregates&ew Mi) *esign $rocedureMi)ture Analysis procedure 'AAMAS(

3


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Superpave Asphalt Binder

Specification

he grading system is based on Climate

$G +, - ..

$erformance

GradeAverage /-day ma)

pavement temperature

Min pavement

temperature


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$G ,+ $G 0. $G 01 $G +, $G /2 $G /+ $G 1.

'#otational 3iscosity( #3

42 42 522 522 522 '552( 522 '552( 552 '552(

'Flash $oint( F$

,+ 0. 01 +, /2 /+

,+ 0. 01 +, /2 /+

'#!667&G "7& F76M !3E&('#!667&G "7& F76M !3E&( #F!#F! Mass 6ossMass 6oss 88 5922 :5922 :

'*irect ension( *

';ending ;eam #heometer( ;;# $hysical "ardening

.1

-


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$G ,+ $G 0. $G 01 $G +, $G /2 $G /+ $G 1.

'#otational 3iscosity( #3

42 42 522 522 522 '552( 522 '552( 552 '552(

'Flash $oint( F$

,+ 0. 01 +, /2 /+

,+ 0. 01 +, /2 /+

'#!667&G "7& F76M !3E&('#!667&G "7& F76M !3E&( #F!#F! Mass 6ossMass 6oss 88 5922 :5922 :

'*irect ension( *

';ending ;eam #heometer( ;;# $hysical "ardening

.1

-


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Aggregate Properties

Coarse and fine aggregate angularity Flat and elongated particles

Sand euivalent results 'Clay content(

7


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Aggregate angularit"Aggregate angularit"


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Percent #racture$ #acesPercent #racture$ #aces


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Re%uirements #or angularit"

Coarse aggregates H based on traffic anddepth from surface

: of 5 or more fractured faces: of . or more fractured faces Fine aggregates H based on traffic and

depth from surface >n-compacted voids

10

100 sbWV G

V


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Re%uirements #or &lat an$ elongate$Re%uirements #or &lat an$ elongate$

particlesparticles

6ongest dimension'6( is compared to

the shortestdimension ';(9

7f 6D; ? 0= thenaggregate is flat or

elongated9


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San$ e%uivalent 'cla" content(San$ e%uivalent 'cla" content(


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Re%uirement #or san$ e%uivalent

raffic H ESA6 'Millions( Sand Euivalent 'Min :(

< 0.3 40

< 1 40

< 3 40

< 10 45

< 30 45

< 100 50

100 50

13


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)ther aggregate properties

6os Angeles Abrasion Sulphate soundness

Absorption

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Aggregate Si*e De#initions

+ominal Maximum AggregateSize

one size larger than the first sieve to

retain more than 52:

MaximumAggregate Sizeone size larger than nominal

ma)imum size

100100

1001009090

7272

6565

4848

3636

2222

1515

99

44

100100

99998989

7272

6565

4848

3636

2222

1515

99

44


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100100

00.075.075 .3.3 2.36 2.36 4.75 4.75 9.59.5 12.5 19.012.5 19.0

$ercent $assing$ercent $assing

control pointcontrol point

restricte$ *onerestricte$ *one

ma) density linema) density line

ma)ma)

sizesizenomnom

ma)ma)

sizesize

Sieve Size 'mm( #aised to 29,0 $owerSieve Size 'mm( #aised to 29,0 $ower


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Superpave Aggregate ,ra$ation

100100

00

.075.075.3.3 2.36 2.36 12.512.5 19.019.0

$ercent $assing$ercent $assing

Design Aggregate StructureDesign Aggregate Structure

Sieve Size 'mm( #aised to 29,0 $owerSieve Size 'mm( #aised to 29,0 $ower


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Superpave Mix Si*e Designations

SuperpaveSuperpave &om Ma) Size&om Ma) Size Ma) SizeMa) Size

*esignation*esignation 'mm( 'mm( 'mm( 'mm(


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Re%uirements #or Control points an$

Restricte$ -one .oun$ar" &ominal ma)imum size determines these

reuirements 'ables ,-+ to ,-52(

. H < trial gradations are used initially foran estimated optimum asphalt content9

he best blend based on min 3MA= &iand&ma)reuirements is selected for the mi)

design9

19


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Specimen Preparation

Mechanical mixer

0.170 Pa-s binder viscosity Short term oven aging

4 hours at 135!

" hours at 135! #o$tional%

&ging allo's absor$tion o(as$halt by aggregates


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.1.1

.2.2

.3.3

.5.5

11

1010

55

100100 110110 120120 130130 140140 150150 160160 170170 180180 190190 200200

)em$erature* !)em$erature* !

+iscosity* Pa s+iscosity* Pa s

Compaction Range

Mixing Range

Mixing/Compaction 0emps


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Specimen Preparation

Specimen "eight Mi) *esign - 550 mm ',/22 g(

Moisture Sens9 - 40 mm '


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Place pre-heated aggregate in bowland add hot aphalt

Mixing


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MixingPlace bo'l on mixer and mix until

aggregate is 'ell-coated


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,m$ty mix into $an and $lace in oven to

simulate short term aging

" hours (or lo' absor$tion aggregates

4 hours (or high absor$tion aggregates

Short 0erm Aging


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Short 0erm Aging mportant

Allows time for aggregate to absorb asphalt "elps minimize variability in volumetric

calculations

Most terms dependent upon volumes whichchange with changes in the amount

'volume( of absorbed asphalt


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Compaction

$lace funnel on top of mold and place mi) in mold9ake care not to allow the mi) to segregate9


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Compaction

$lace another paper on top of mi)

and place mold in compactor9


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29

E)ample of typical full-size compactors9

Compaction


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reaction

frame

rotating

base

loading

ram

control and data

acuisition panel

mold

height

measurement

tilt bar

2e" Components o# ,"rator" Compactor

Compaction


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Compaction

Gyratory compactor

A)ial and shearing action 502 mm diameter molds Aggregate size up to


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+um3er o# ,"rations '+(

*epends on ESA6s and Av9 *esign "igh Airemperature9

;e as &i= &dand &m9

&dis &-design and is the number of gyrations

reuired to produce density euivalent to fielddensity at ,: air voids9

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+um3er o# ,"rations '+(

&iis &-initial and is the number of gyrationsreuired to produce mi)tures with at least 55: air

voids9 his avoids tender mi)es9

&mis &-ma)imum and is the number of gyrationsreuired to produce mi)tures with a laboratory

density never achievable in the field '.: air voids(9

&iI '&d(29,0and &mI '&d(5952

33


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After aging= take mi) and preheated moldfrom oven9 $lace paper in bottom of mold9

Compaction


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!nce compaction is finished= e)trudesample from mold9

Compaction


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Compaction

#emove the paper and label samples9


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Densit" Determination

he bulk densities are determined at thedifferent levels of &9

hese are got both by computer'calculated( and measurement 'Actual(9 A correction factor 'CF( is then obtained I

Actual densityDcalculated density9

6oose samples of mi)tures are used todetermine the G

mm9

37


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Selection o# )ptimum AC

*etermine estimated opt AC using trialblends9

$repare specimens at 290: below !AC= at!AC= 290: and 592: above !AC9 Mi) each sample and oven age at 5


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Selection o# )ptimum AC

#emove from mold and determine Gmbat&m9

*etermine the CF and ad%ust air voids at &iand &d9

$lot $ercent Gmm I 522@'GmbDGmm(

#ecall &iI? 55: Avoids= &dI? ,: Avoidsand &

mI? .: Avoids

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S,C Results

mm

/og yrations

10 100 1000


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mmmm

/og yrations/og yrations

1010 100100 10001000

iniini

desdesmaxmax

0hree Points on S,CCurve


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Design Compaction

&desbased on

average design highair temp

traffic level

6og &ma)I 5952 6og &des 6og &iniI 29,0 6og &des

mm

/og yrations10 100 1000

ini

des

max


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umber o( yrationsumber o( yrations

44

22

00

""

44

22

100100

11 1010 100100 10001000

S$ecimen 1S$ecimen 1

S$ecimen "S$ecimen "

&verage&verage

mmmm

maxmax 174 174

desdes 10 10

iniini

Data Presentation


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Superpave Mix Design Anal"sis


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Superpave 0esting

Specimen heights Mi)ture volumetrics

Air voids 3oids in mineral aggregate '3MA( 3oids filled with asphalt '3FA( Mi)ture density characteristics

*ust proportion Moisture sensitivity

Superpave Mix Design


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Gmb'estimated( I m


!"#$

hereJ

mI mass of specimen= g3m)I volume of compaction mold 'cm


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"owever= surface irregularities cause the volume of the

specimen to be slightly less than volume of cylinder Actual bulk specific gravity measurement of compacted

sample used to determine correction factor= CJ


C IGmb'measured(

Gmb'estimated(

: GmmI Gmb'estimated( C D Gmm'measured(


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*etermine mi) properties at &*esignand compare tocriteria

Air voids ,: 'or 4+: Gmm(

3MA See table 3FA See table

:Gmmat &ini 8 14:

:Gmmat &ma) 8 41: *ust proportion 29+ to 59.


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S,C Results

: Gmm

6og Gyrations52 522 5222

ncreasing asphalt

cement content

Each line I avg9 of two samples

inides max

4+:

',: 3oids(

S Mi D i


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50

3MA reuirementsJ&ominal ma) agg size Min9 3MA

%490 mm 50

%5.90 mm 5,%54 mm 5

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