Study on Asphalt Pavement Technologies Study on Asphalt Pavement Technologies Targeting the Prevention of Global Warming Targeting the Prevention of Global Warming

Masahiko Iwama, Tamotsu Yoshinaka, , Tamotsu Yoshinaka, Shinobu Omoto and Nobuyuki NemotoShinobu Omoto and Nobuyuki Nemoto

International Road Federation International Road Federation 1616th th World MeetingWorld Meeting

May 25th to 28th 2010, Lisbon, Portugal

Outline of Presentation

� Use of Warm-Mix Asphalt- Basic concept- Laboratory test results- Laboratory test results- CO2 reduction at paving work

� Solar Heat-blocking Pavement- Basic concept- Effect of temperature reduction- Case study (Airport taxiway)

� Conclusions

Warm-mix Asphalt - Background -

Warm-Mix Asphalt:- Reduction in CO2

- Improvement of workability, especially in winter- Improvement of workability, especially in winter• In 1997, NIPPO developed the additive agent

called “ECOFINE”• It can be used for both straight and modified

asphalts• 30 °°°°C to reduction in mixing temperature was

achieved

What is ECOFINE ?Forming-based special additive agent for WMA technologyProduction： Fine forms occur in bitumen

A volume of bitumen increases considerablyWorkability of bitumen will be improved

Laying： Good compaction is achieved by “bearing effect”

●

Laying： Good compaction is achieved by “bearing effect”Roller Compaction

Asphalt mixture

Coarse aggregate Mastic

Fine forms

Properties of ECOFINE-Micro-form generation-

• Add the agent of 2 kg/ton • Keep forming state for a long duration;

• Laboratory: Approx. 120 min.• Site: 4 to 5 hours• Site: 4 to 5 hours

Special Additive

100

200

300

400

0 20 40 60 80 100 120 140

Bit

um

en %

by

Vo

lum

e

Duration Time of Foaming (min.)

Foaming Agent only

Special Additive

Straight Asphalt 60/80, 130°CSpecial Additive : 7% by mass of bitumen

Warm-mix AsphaltLaboratory test results

100

101

102

103

Co

mp

acti

on

Deg

ree

(%)

■■■■ ECOFINE■■■■ Without Additive

Dense Asphalt Concrete / Max.Size13mmStraight Bitumen 60/80Mixing Temp. : 130℃

Normal Asphalt MixtureMixng Temp. : 160℃Compac.Temp. : 140℃

95

96

97

98

99

100

707070708080808090909090100100100100110110110110120120120120130130130130

Co

mp

acti

on

Deg

ree

Compaction Temperature (℃℃℃℃)

Mixing Temp. : 130℃

Warm-mix AsphaltLaboratory test results

1.4

1.8

2.2

10 10 10 10 12 12 12 12 14 14 14 14 16 16 16 16

Rav

ellin

g A

bra

sio

n (

cm2 )

Mar

shal

l Sta

bilit

y M

arsh

all S

tabi

lity

Mar

shal

l Sta

bilit

y M

arsh

all S

tabi

lity (

kNkN kNkN) Dense Asphalt Concrete / Max.

Size13mm Straight Bitumen 60/80

0.2

0.6

1

1.4

0 0 0 0 2 2 2 2 4 4 4 4 6 6 6 6 8 8 8 8

10 10 10 10

Normal Asphalt Mixture

ECOFINE 30℃℃℃℃ Lower

Without Additive 30℃℃℃℃ Lower

Rav

ellin

g A

bra

sio

n

Mar

shal

l Sta

bilit

y M

arsh

all S

tabi

lity

Mar

shal

l Sta

bilit

y M

arsh

all S

tabi

lity

Stability

RavellingAbrasion

ECOFINE

Simplification of paving equipment train:CO2 reduction at paving work

� Simplified compaction train was examined

Section A (Control)Mixture: at normal temp. without additiveRollers: 10 t macadam roller +

pneumatic tired roller

Section B (Trial)Mixture: at normal temp. with additiveRollers: 6 t combined roller

100 m 100 m

3.75 mPlane figure

Construction condition and test resultsType of Mix.

ItemsSurface Mixture Type 20

Applied Section A (Control) B (Simplified)

Special Addition 0 3.5

Mixing Conditions

Capacity of Mixer 2,000 kg/batch

Dry Mixing Time (sec) 10

Wet Mixing Time (sec) 36Conditions Wet Mixing Time (sec) 36

Mixing Temp. (ﾟC) 160

Compaction (time)

Macadam Roller 3 -

Pneumatic Tired Roller 7 -

6 t Combined Roller - 11

Cored SampleDensity (g/cm3) 2.339 2.324

Air Void (%) 4.8 5.4

Compaction Degree (%) 98.9 98.6

Evenness (σ) (mm) 0.79 0.78

CO2 reduction at paving work- Calculated CO2 emission -

PneumaticTired Roller40

50

60

Dis

char

ge

(kg/h)

52.9 （（（（kg/h））））

53%

• Approx.53% of CO2 reduction can be saved thanks to the special additive

AsphaltPaver

4 tonCombined Roller

AsphaltPaver

MacadamRoller

0

10

20

30

40

Cal

cula

ted

CO

22 22 D

Simplified Normal Combination

24.8 （（（（kg/h））））

Solar HeatSolar Heat--blocking Pavementblocking Pavement

Solar Heat-blocking Pavement- Background -

Urban areas and pavements in JapanUrban areas and pavements in Japan� Surface temperatures of asphalt pavement reach

60ﾟ゚゚゚C or higher in summer Asphalt surfaces cover approx. 20% of urban areas � Asphalt surfaces cover approx. 20% of urban areas

� Pavement is a source of heat, similar to concrete structures

Hotter pavement:Hotter pavement:- leads to the urban heat island phenomenon- may affect the heath of pedestrians due to the

higher temperatures

Basic concept of solar reflective technology

Surface course of hot mix asphalt

◆◆◆◆ Low reflection for the visible rays

◆◆◆◆ High reflection for the near infrared raysSolar radiation

Hollow ceramic particle Highly reflective pigment

Aggregate

Asphalt

Apply high albedo and dark colored

thin treatment materials

Component of hot mix asphalt

Albedo characteristics of treatment materials

60

80

100

Alb

edo

(%

)Visiblerays

Near-infrared rays

New surface treatment materials L*40(dark gray)

Albedo: Degree of reflection

�Straight asphalt has a very low albedo�Dark-gray treatment materials have a low albedo for visible rays, but

a very high albedo (about 90%) for near-infrared rays

0

20

40

60

400 600 800 1000 1200 1400 1600 1800 2000 2200500 1000 1500 2000

Alb

edo

(%

)

Wavelength (nm)

Normal paint materials L*40(dark gray)

Straight asphalt 60/80

Performance of heat blocking pavement

40

50

60

70S

urfa

ce te

mpe

ratu

re (

C゚) 8/11 - 8/13 2004 Kyoto

16ﾟ゚゚゚C

Dense graded surfaceSolar heat-blocking pavement

Max. air temperature:37.8ﾟC

10

20

30

Sur

face

tem

pera

ture

8/11 8/12 8/130：00 0：00 0：00

Ambient temperature

� The maximum temperature of the conventional pavement rose to 57.4ﾟ゚゚゚C

� The temperature of the treated surface was reduced by about 16ﾟ゚゚゚C

Case study- Rutting mitigation at airport taxiway -

B’-runway

Construction area

Narita International Airport

3

63 2

4

1

0

25

B747

A300

MD11

B757

B737

A320，，，，310 Other

Small11％％％％

A380≒≒≒≒0

Size:

� Temperatures both in conventional surface and S.H.P. were measured at 20 mm, 80mm and 200mm below the surface

Terminal 1, 2

A-runway

area

Garage

12

19

25

B777

A340，，，，330

B767

Large62％％％％

Middle27％％％％

Size:

Temperature of pavements

Surface (20 mm below)

010203040506070

Max

. tem

pera

ture (°C

)

12 3 6 9 12 3 6 9 12 3 6 9 120 12 24 36

Max

. tem

pera

ture

12 3 6 9 12 3 6 9 12 3 6 9 12

Milled Surface (200 mm below)

010203040506070

0 12 24 36

Max

. tem

pera

ture (

°C) Conventinal

S.H.PAmbinet temp.

12 3 6 9 12 3 6 9 12 3 6 9 12

2006 2007 2008

Month

30

40

50

30

40

50

Rut

dep

th (

mm

)

Max

. ru

t dep

th (

mm

)

Rut depth (S.H.P.) Rut depth (Conventional)

Max. rut depth (Conventional)

34Max. rut depth (S.H.P.)

Differences of rut depth

0 0 0 1 00 0 0 1 00

10

20

30

0

10

20

30

2 months 1 year 1.5 years 2 years 2.5 years 3 years 3.5 years 4 years 4.5 years

Rut

dep

th (

mm

)

Max

. ru

t dep

th (

mm

)

2006.7 2007 2008 2009

16

After

Conclusions

� The application of micro-forms WMA(ECOFINE) enables the production and laying temperature to be 30 °°°°C lower than normal bitumen.

� Approx. 50% of CO2 generation can be reduced by � Approx. 50% of CO2 generation can be reduced by decreasing the number and size of rollers.

� The reduction in surface temperatures for the heat-blocking pavement is approximately 16 °°°°C .

� This technology would be effective to the rutting as the rate of rut depth was approximately a half, compared to the dense-graded asphalt surface at the taxiway .

Thank youThank youThank youThank you

Properties of ECOFINE Estimated CO2 emission; 30 to 50 °C reduction

20

22

Dis

char

ge

(kg/ton)Asumption for calculation : Moisture content % agg. : 3% Ambient Temp. : 30゚゚゚゚C

14

16

18

100110120130140150160170180

M ixing Temperature (゚゚゚゚C )

Est

imat

ed C

O2

D

14%23%

Case studies- Highway maintenance -

• Divided the maintenance area into 4 sections

• Compared construction time between Control and ECOFINE sections in surface, binder course and L.S.M.

L = 400 m

Section A (ECOFINE)

Section B(Control)

Section C(ECOFINE)

Section D(Control)

Surface

Binder course

Surface

Large Stone Mix (L.S.M.)

2 cm

3 cm

2 cm

5 cm

W=3.5 m

t = 4 cm

t = 10 cm

L = 400 m

: Thermo-Couple

Plane figure

Sectiont = 6 cm

Case studies - Highway maintenance -

Mixture Surface Binder course Large Stone Mix.

Control ECO ECO FINEFINE

Control ECO ECO FINEFINE

Control ECO ECO FINEFINE

ItemFINEFINE FINEFINE FINEFINE

Density (g/cm3)

2.314 2.309 2.369 2.363 2.379 2.378

Air Void (%)

5.7 5.9 4.1 4.3 4.6 4.6

Compaction Degree (%) 97.7 97.5 100 99.8 99.0 99.0

Case studies - Highway maintenance -

Item

Section

Rut depth (mm) Evenness (mm) Skid resistance (BPN)

After construction

After 6 months

After construction

After 6 months

After construction

After 6 months

Note: Section A Surface + Binder course (ECOFINE) , B Surface + Binder course (Control)

Section C Surface + Large Stone Mix. (ECOFINE), D Surface + Large Stone Mix. (Control)

construction 6 months construction 6 months construction 6 months

A 1 1 0.86 1.03 70 72

B 2 2 0.74 0.82 73 68

C 1 1 0.98 0.84 72 70

D 1 1 0.79 0.82 74 71

Case studies - Highway maintenance - Surface & Binder courses

90

120

150

180

empe

ratu

re (

°C)

ECOFINE BinderControl BinderECOFINE SurfaceControl SurfaceExisting SurfaceAmbient Temp.

○○○○

△△△△

4cm6cm

Surface （（（（ TypeA ））））

Binder

Location ofThermo-Couple

Time diffrence when surface temp. is at 60°C　　　　　　　　　　　　　　　　　　　　　　　　　　　　 about 50 min.

0

30

60

90

0 60 120 180 240 300 360 420 480

Time (min.)

Tem

pera

ture

(°C

)

Temp.difference of Surface Layer : about 4°C Temp.difference of Binder Layer : about 4°C

Case studies - Highway maintenance - Surface & Large Stone Mix.

90

120

150

180T

empe

ratu

re (

°C)

ECOFINE L.S.M. （（（（Section C））））Control L.S.M. （（（（Section B））））ECOFINE Surface （（（（Section C））））Control Surface （（（（Section D））））Existing SurfaceAmbient temp.

4cm

10cm

Surface(TypeⅡⅡⅡⅡ Modified B)

Large Stone Mix

●

●

Location ofThermo-Couple

Time diffrence when surface temp. is at 60°C　　　　　　　　　　　　　　　　　　　　 about 70 min.

0

30

60

90

0 60 120 180 240 300 360 420 480

Time（ min.）

Tem

pera

ture

(°C

)

Temp.difference of Surface Layer : about 8°C Temp.difference of Large Stone Mix : about 6°C

Environmental issuesHotter pavement:Hotter pavement:- leads to the urban heat island phenomenon- may affect the heath of pedestrians due to the

higher temperatures

Public demand to reduce the temperature of road pavementPublic demand to reduce the temperature of road pavement

Research & DevelopmentBasic conceptHighly reflective pigmentHighly reflective pigmentHighly reflective for near-infrared rays→ Prevention of heatingLow reflectivity for visible rays→ Enables various colors to be selected

Hollow ceramic particlesHollow ceramic particles- Reflect solar radiation to the atmosphere

Hollow ceramic particles

（5～150µm）

What is solar radiation?

1,500

2,000

W/m2

� Solar radiation mainly consists of visible rays and near-infrared rays and includes some ultraviolet rays

� 50% of solar energy is visible rays; the rest is near-infrared rays

0

500

1,000

150 360 750 3,000nm

VisibleVisibleraysrays

NearNear--infrared raysinfrared raysUltravioletrays

Infrared rays

NearNear--infrared raysinfrared rays

≒≒≒≒≒≒≒≒50%50%

Visible raysVisible rays

≒≒≒≒≒≒≒≒50%50%

Section of pavements

Solar Heat-blocking Pavement Conventional Surface

▲▲▲

Surface (20 mm below)Inter layer (80 mm below)

Milled surface (200 mm below)

Depth ofThermo-couple

Surface: Large stone mix. (Modified Asphalt)

Bituminous stabilization

Cement stabilization

Crusher-run

Coated layer

t= 80 mm

Binder course: Large stone mix. (Modified Asphalt) t=120 mm

t=200 mm

t=500 mm

t=300 mm

Constructionoverview

Thermo-couple