cedr transnational road research programme call 2012: … · 2016-11-24 · cedr transnational road...

CEDR Transnational Road Research ProgrammeCall 2012: Recycling: Road construction in a post-fossil fuel societyfunded by Denmark, Finland, Germany,Ireland, Netherlands and Norway

Toward a sustainable 100% recycling of reclaimed asphalt in road pavements

Gustavo Canon FallaResearch Fellow, Institute of urban and pavement engineering

Technische Universität Dresden

International workshop on Recycling: Roadconstruction in a post‐ fossil fuel society

http://allback2pave.fehrl.orgInternational workshop on Recycling: Roadconstruction in a post‐ fossil fuel society

Objectives

AllBack2Pave is a research project project that will evaluate the feasibilityof going towards 100% recycling of asphalt pavements into surfacecourses.


Objectives

AllBack2Pave is a research project project that will evaluate the feasibilityof maximizing the amount of recycling of asphalt pavements intosurface courses.

The main objectives of the project are:

• To establish, through laboratory tests on binders and asphalt mixes,whether the use of high rates of RA is feasible in developing mixeswith a high level of performance which do not affect the durability.

• To develop the so-called “AllBack2Pave end-user manual” on how tobest produce cost-effective and quality asphalt mixes with high RAcontent.


Consortium


Project organization


Methodology

• Two typical asphalt surface mixes ofhigh volume roads of Germany andItaly.

• Mix design and production followingeach country regulatory environment.

• Three different amounts of RA in eachmix.

Control mixes

DE: SMA 8S

IT: AC 16

Control mixes

DE: SMA 8S

IT: AC 16

30% RA

DE30

IT30

30% RA

DE30

IT30

60% RA

DE60

IT60

60% RA

DE60

IT60

Max% RA

DE60+Add.

IT90

Max% RA

DE60+Add.

IT90


Materials: DE

Cold virgin aggregatesHot virgin aggregatesFibresFinesCold RAHot RAVirgin BitumenAdditivesHot mix

1 Stockpiles of virgin aggregates2 Cold Feeders3 Aggregates heating drum4 Fibre silo5 Aggregate elevator6 Filler silo7 Screen / Fractioning8 Aggregate scale9 Parallel heating drum for RA10 Bitumen tank11 RA elevator12 RA screen13 Stockpiles of RA14 Mixer15 Additive addition16 Hot mix storage silo


Materials: DE

Sand

Fine

sFi

bres

Virg

inB

itum

enA

dditi

ves

RA

Coa

rse

Agg

rega

tes Crushed stone 8/11 Quarry in Gilching

2 buckets of 15kg each foreach aggregate.

Crushed stone 8/11 Quarry in TreidlingCrushed stone 5.6/8

Crushed stone 2/5.6 Quarry in Treidling

Material Source / Producer Sampling

Quarry in GilchingCrushed stone 5.6/8 Quarry in TreidlingCrushed stone 2/5.6 Quarry in Gilching

Sand 0/2 Quarry in Gilching 2 buckets of 15kg each

Fines Quarry in Lauterhofen 1 bucket of 15 kg

Fibres Viatop premium 1 bucket of 5 kg

Bitumen(PmB 25/55-55) OMV 1 bucket of 15 Kg

Blend of rejuvenatorand WMA Storimpex 1 sample of 5 kg was

obtained from the producer

Reclaimed asphaltSMA 11S

Rehabilitation of A8 highwaynear Munich

10 buckets of 15 kg each.The buckets were filled withRA from 5 random locations ofthe stockpile

Virginminerals

Virginminerals FibresFibres Virgin

bitumenVirgin

bitumen AdditiveAdditive RARA


Materials: IT

Virginminerals

Virginminerals

VirginbitumenVirgin

bitumen AdditiveAdditive RARA


Hot mix recycling process

Reclaim theasphalt

Process theRA

Characterizethe RA

Mix designMixingTransport andpaving

Maintenance End of lifeReclaim the

asphalt (multiplerecycling)


Reclaim the asphalt

• Mill out from the surface layer of ahigh volume road near Munich(highway A8).

• The RA was made up of abituminous surface originallydesigned as a SMA with a nominalgrain size of 11mm (SMA 11S) anda Polymer modified bitumen (PmB25/55-55).

• The original mix design formulasand maintenance history of the RAwere not available

German RA Italian RA

• Mill out from the surface layer ofan urban road

• The RA was made up of abituminous surface originallydesigned as an AC with a nominalgrain size of 16mm



• Mill out from the surface layer ofan urban road

• The RA was made up of abituminous surface originallydesigned as an AC with a nominalgrain size of 16mm


Reclaim the asphalt

• Mill out from the surface layer of ahigh volume road near Munich(highway A8).

• The RA was made up of abituminous surface originallydesigned as a SMA with a nominalgrain size of 11mm (SMA 11S) anda Polymer modified bitumen (PmB25/55-55).



RA properly milled (i.e. layer by layer)

Mix desing formulas, material andmaintenance records of RA

RA properly milled (i.e. layer by layer)

Mix desing formulas, material andmaintenance records of RA



Reclaim theasphalt

Process theRA

Characterizethe RA


Maintenance RehabilitationReclaim the



Process the RA

• RA crushed in the mixing plant to amaximum grain size of 22 mm

• RA stored in stockpiles withoutfurther screening

• Open air storage


• RA crushed in the mixing plant to amaximum grain size of 20 mm

• RA stored in stockpiles withoutfurther screening

• Under shelter storage


Process the RA

• RA crushed in the mixing plant to amaximum grain size of 22mm

• RA storage in stockpiles withoutfurther screening

• Open air storage


• RA crushed in the mixing plant to amaximum grain size of 20mm

• RA storage in stockpiles withoutfurther screening

• Under shelter storage

RA properly stored (e.g. under shelter)

Fractionation of RA

RA properly stored (e.g. under shelter)

Fractionation of RA



Reclaim theasphalt

Process theRA

Characterizethe RA





Characterize the RA

Binder extractionand recovery

Testing of RAaggregates

Testing ofBinder

Bitumen content


Characterize the RA



Testing ofBinder

Mineral

Agedbitumen

BlackAggregate

WhiteAggregate

Partial blendingconcept


Characterize the RA



Testing ofBinder

Blackcurve

Whitecurve

Partial blendingconcept

Greycurve


Characterize the RA



Testing ofBinder

Grading

Whitecurve



Characterize the RA



Testing ofBinder

PSV.

The aggregates ability to resistskidding is crucial when designing

wearing course mixes.


Characterize the RA



Testing ofBinder

Angularity

C100/0 C100/0


Characterize the RA



Testing ofBinder

Conventionalproperties


Characterize the RA



Testing ofBinder

PG grade testing



Reclaim theasphalt

Process theRA

Characterizethe RA





Mix design

What is the maximum amount of RA that couldbe allowed in the mix?

VirginBinder

RABinder

VirginAggregates

RAAggregates

Choose highest RA that satisfies bothaggregate gradation and bitumen

requirements

Combine bitumen to meetspecification requirements

Combine aggregates tomeet gradationA

ggre

gate

path


Mix design

The RA grading needs to be modified by additionof virgin aggregates


Mix design

Max RA in mix: 70% -w

German Mix

Max RA in mix: 100% -w

Italian Mix


Mix design

What is the maximum amount of RA that couldbe allowed in the mix?

VirginBinder

RABinder

VirginAggregates

RAAggregates

Choose highest RA that satisfies bothaggregate gradation and bitumen

requirements

Combine bitumen to meetspecification requirements

Combine aggregates tomeet gradation

Bitu

men

path

Blendingcharts


Mix design

Virginbinder

property

RAbinder

property

Replaced bitumen content

The charts correlate the replaced bitumen content (RBC) with theempirical properties of the blend.

By replaced bitumen content it should be understood the percentageof bitumen from the RA in the final blend.

Blending charts


Mix designGERMAN CASE:

• Use available RA (short term aged) and perform the design withand without rejuvenator

• Rejuvenator:o virgin PmB 25/55-55o partly rejuvenator + warm mix additive (mix)


Mix designGERMAN CASE:

• Use available RA (short term aged) and perform the design withand without rejuvenator

• Rejuvenator:o virgin PmB 25/55-55o partly rejuvenator + warm mix additive (mix)

These charts are developed assuming that 100% of the RAbinder will be mobilized and become active part of the binder in

the new mix.

However, in reality it is also possible that part of the RA bitumenremain non-active resulting in a partial blending scenario.


Mix design

GERMAN CASE:

Blending charts includingdegree of blending between

60% and 100%


Mix design

GERMAN CASE:

• Binder blend design based on conventional properties shows that by using theselected binder PMB 25/55-55 as a virgin binder for the selected RA-mixes(30%,60%, and 70%), it is possible to obtain a final blend whom properties arestill within the limits of Pen and SP

%RA in the mixture

Penetration(25⁰C)(d mm)

Softening Point(⁰C)

Final Blend (30% RA) 37.3 61.5

39.7 61.0

Final Blend (60% RA)32.3 62.6

36.6 61.6

Final Blend (70% RA)30.8 63.0

35.7 61.8

target 25-55 ≥55


Mix design

GERMAN CASE:

• Binder blend design based on performance-related properties shows that byusing the selected binder PMB 25/55 (VB-D) as a virgin binder for theselected RA-mixes (30%,60%, and 70%), it is possible to obtain a final blendwhom properties do not differ too much from the selected Virgin binder

%RA in the mixture High Tc(⁰C)

Intermediate Tc (⁰C)

Low Tc(⁰C)

Final Blend (30% RA)79.5 19.9 -15.5

79.5 19.6 -15.7

Final Blend (60% RA)79.7 20.6 -14.9

79.6 20.2 -15.4

Final Blend (70% RA)79.8 20.8 -14.8

79.6 20.1 -15.3

Target (VB-D) >79.3 <19.2 <-16.0


Mix designITALIAN CASE:

• Use available RA (long term aged) and perform the design withrejuvenator

• Rejuvenators:o virgin bitumen 50/70o rejuvenator + warm mix additive (mix)

y = 0.0013x + 1.8325

y = 0.0025x + 1.8325

1.8

1.85

1.9

1.95

2

2.05

2.1

0 10 20 30 40 50 60 70 80 90 100

LOG

Pen

etra

tion

(25⁰C) (lo

g d

mm

)

%RVB

Rejuvenated RAPb with RejA Rejuvenated RAPb with RejB

y = 0.208x + 47.6

y = 0.181x + 47.6

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 100

Soft

enin

g P

oint

(⁰C)

%RVB

Rejuvenated RAPb with RejA Rejuvenated RAPb with RejB


Mix design

ITALIAN CASE:• Binder’s blend design based on conventional properties shows that by

using the selected binder Pen 50/70 as a virgin binder and RejA and RejBfor the selected RA-mixes (30%,60%, and 90%), both Pen and SP valuesstruggle to achieve the target

%RA in themixture

Final properties of blendwith RejA

Final properties of blendwith RejB


SofteningPoint(⁰C)


SofteningPoint(⁰C)

30%RA71.0 50.5 73.7 50.273.9 53.3 79.5 52.6

60%RA70.4 53.4 79.8 52.780.3 59.0 92.9 57.5

90%RA77.3 56.4 86.5 55.287.2 64.7 108.7 62.5

target 50-70 >54 50-70 >54


Mix design

ITALIAN CASE:• Blend design based on performance-related properties shows that by using

the selected binder Pen 50/70 as a virgin binder and RejA and RejB for theselected RA-mixes (30%, 60%, and 90%), it is possible to obtain a finalblend with comparable properties to the target binder VB.

Final properties of blendwith RejA

Final properties of blendwith RejB

Binder High Tc(⁰C)

IntTc

(⁰C)

Low Tc(⁰C)

High Tc(⁰C)

IntTc

(⁰C)

Low Tc(⁰C)

RAb 87 33 -6 87 33 -6Final Blend (30% RA –

white100) 67.1 16.9 -16.6 67.1 16.6 -14.4

Final Blend (60% RA –white100) 68.5 14.8 -18.1 68.4 14.2 -13.9

Final Blend (90% RA –white100) 69.8 12.7 -19.7 69.7 11.8 -13.3

target (VB) >66 <19 <-16 >66 <19 <-16


Mix design process in lab

Combine virginaggregates for

gradation

Combine virginaggregates for

gradation

Heat virginaggregatesHeat virginaggregates Add RAAdd RA

Heat RA + VirginAggregates

Heat RA + VirginAggregates Add virgin bitumenAdd virgin bitumen

Performconventional

volumetric mixdesign

Performconventional

volumetric mixdesign

Performperformance tests

Performperformance tests

T=180°CTime=8h 30%,60%,90%

T=120°CTime=3h


Conclusions• The heterogeneity of the RA aggregates plays an important role when

designing asphalt mixes for wearing courses where high qualityaggregates with high resistance to wear/abrasion (polishing) areneeded.

• Properly milled (i.e. layer by layer) and stockpiled RA is a mandatoryprerequisite in order to produce durable asphalt wearing courses withhigh content of RA.

• The RA must be treated as a valuable material

• In order to produce mixes with high RA content, a balanced mix designapproach must be followed.

• One possible solution is to allow the use of high percentage of RA inwearing courses only if the RA material proceeds from the samelocation and layer where the new mix will be placed.

cedr transnational road research programme call 2012: … · 2016-11-24 · cedr transnational road...

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