Portorož, Slovenia
Thin asphalt layers for highways – optimised for low tyre / road noise
•Bent AndersenBent Andersen
•Danish Road Directorate / Road InstituteDanish Road Directorate / Road Institute
•Senior reseacher / Traffic NoiseSenior reseacher / Traffic Noise
•[email protected]@vd.dk
Portorož, Slovenia
Background and purpose
o First thin layer experiment in Denmark: 6 test pavements i 2004 at M10. Danish Road Directorate
o Second experiment: 11 test pavements in 2006 at M64. Part of DRI-DWW noise abatement program
o Purpose:
• Develop and optimise thin semi-dense pavements for highway application
• Monitor performance over time:– noise (SPB and CPX), texture, and friction
Portorož, Slovenia
Measurement program
o Noise • SPB method (ISO 11819-1)• CPX method (ISO/CD 11819-2)
o Texture (laser profilometer)
o Friction (wet, 20% slip, 60 km/h)
Portorož, Slovenia
Thin layers at M10 - DK 2004
o 110 km/ho 84000 veh/24ho Ref. AC 11d
• SMA 8• AC 8o• UTLAC 8• SMA 6+• SMA 8+
Portorož, Slovenia
SPB results for cars at 110 km/h
oRange ≈ 3 dB
oNord2000 ref. (8 years):
83.8 dB
oNoise reduction2 – 5 dB initially0 – 2 dB 4 years
oBest surfaces:AC 8oSMA 6+
Passenger cars 110 km/h
76
78
80
82
84
86
0 1 2 3 4 5
Age [yrs]
Lve
h [d
B]
AC 11dSMA 8UTLAC 8SMA 6+AC 8oSMA 8+
Portorož, Slovenia
SPB results for multi-axle trucks at 85 km/h
oRange ≈ 3 dB
oNord2000 ref. (8 years, 5 ax):
88.5 dB
oNoise reduction1 – 2 dB initially-1– 2 dB 4 years
oBest surfaces:AC 8oUTLAC 8SMA 8
Multi-axle trucks 85 km/h
82
84
86
88
90
92
0 1 2 3 4 5
Age [yrs]
Lve
h [d
B]
AC 11dSMA 8UTLAC 8SMA 6+AC 8oSMA 8+
Portorož, Slovenia
SPB results for dual-axle trucks at 85 km/h
oRange ≈ 3 dB
oBest surfaces:AC 8oUTLAC 8SMA 8
Dual-axle trucks 85 km/h
80
82
84
86
88
90
0 1 2 3 4 5
Age [yrs]
Lve
h [d
B]
AC 11dSMA 8UTLAC 8SMA 6+AC 8oSMA 8+
Portorož, Slovenia
New experiment 2006: M64, Herning-1
o90 km/ho7100 veh/24hoRef. AC 11d
oOptimize mix ← intl. experienceoMax aggregate size 6+ mmoIncrease built-in air voido4 pavement families:
• SMA• UTLAC• BBTM• AC o
Portorož, Slovenia
Herning-1 test surface data, M64
PavementMax. aggr.
[mm]Air void
[%]Thickness
[mm]
UTLAC 8 8 12 22
UTLAC 6 6 13 18
BBTM 6 – cl. 2 6 14 24
BBTM 8 – cl. 1 8 14 25
BBTM 8 – cl. 2 8 16 24
SMA 6 6 9 18
SMA 6+ 6 + 5/8 6 22
SMA 8 8 8 24
AC 6o 6
AC 8o 8
DAC 11 11 2.3 -
Portorož, Slovenia
0
10
20
30
40
50
60
70
80
90
100
AC 11 dense
SMA 6
SMA 6+
SMA 8
0,063 0,125 0,250 0,5 1 2 4 5,6 8 11,2 16 [mm]
Pe
rce
nta
ge
pa
ss
ing
[%
]
SMA 6, SMA 6+, SMA 8 and AC 11 (ref.)
Grading curves – SMA
Portorož, Slovenia
DAC 11
SMA 6
SMA 6+
SMA 8
Portorož, Slovenia
Grading curves – UTLAC
0
10
20
30
40
50
60
70
80
90
100
AC 11 dense
UTLAC 6
UTLAC 8
0,063 0,125 0,250 0,5 1 2 4 5,6 8 11,2 16 [mm]
Pe
rce
nta
ge
pa
ss
ing
[%
]
UTLAC 6, UTLAC 8 and AC 11 (ref.)
Portorož, Slovenia
DAC 11
UTLAC 6
UTLAC 8
Portorož, Slovenia
Grading curves – BBTM (semi-porous)
0
10
20
30
40
50
60
70
80
90
100
AC 11 dense
BBTM 6 Class 2
BBTM 8 Class 1
BBTM 8 Class 2
0,063 0,125 0,250 0,5 1 2 4 5,6 8 11,2 16 [mm]
Pe
rce
nta
ge
pa
ss
ing
[%
]
BBTM 6 Class 2, BBTM 8 Class 1, BBTM 8 Class 2 and AC 11 (ref.)
Portorož, Slovenia
DAC 11
BBTM 6 Cl-2
BBTM 8 Cl-1BBTM 8 Cl-2
Portorož, Slovenia
SPB results for cars at 90 km/h, year 0
oRange 73.8 – 78.6 dB
oUncertainty (95% conf.) ≈
± 0.2 dB
73
74
75
76
77
78
79
Lve
h [
dB
]
UTLAC8 BBTM8 cl-1 BBTM8 cl-2 DAC11 SMA8 SMA6
AC8o UTLAC6 BBTM6 cl-2 SMA6+ AC6o
Portorož, Slovenia
SPB results for cars at 90 km/h, year 0 & 1
Passenger cars 90 km/h
72
74
76
78
80
82
0 1 2 3 4 5
Age [yrs]
L ve
h [d
B]
UTLAC 8BBTM 8 Cl. 1BBTM 8 Cl. 2DAC 11SMA 8UTLAC 6BBTM 6 Cl. 2SMA 6+AC 8oAC 6o
oRange 5 – 6 dB
oNord2000 ref. (8 years):
80.5 dB
oNoise reduction2 – 7 dB initially1 – 7.4 dB 1year
oBest surfaces:AC 6oAC 8o SMA 6+
Portorož, Slovenia
SPB results for multi-axle trucks at 80 km/h, year 0
81
82
83
84
85
86
87
88
89
90
Lve
h [
dB
]
UTLAC8 UTLAC6 DAC11 SMA6 BBTM8 cl-1 BBTM8 cl-2
AC6o AC8o BBTM6 cl-2 SMA6+ SMA8 oRange 84.5 – 87.5 dB
oUncertainty (95% conf.) ≈
± 0.4 dB
Portorož, Slovenia
Trucks 80 km/h
82
84
86
88
90
92
0 1 2 3 4 5
Age [yrs]
L ve
h [d
B]
UTLAC 8BBTM 8 Cl. 1BBTM 8 Cl. 2DAC 11SMA 8UTLAC 6BBTM 6 Cl. 2SMA 6+AC 8oAC 6o
SPB results for multi-axle trucks at 80 km/h
oRange ≈ 3 dB
oNord2000 ref. (8 years, 5 ax):
87.7 dB
oNoise reduction0 – 3 dB initially.5 – 3.7 dB 1year
oBest surfaces:AC 6oSMA 8, AC 8o,BBTM 8 Cl. 2
Portorož, Slovenia
40
45
50
55
60
65
70
63 100
160
250
400
630
1000
1600
2500
4000
6300
Frequency [Hz]
[dB
(A)]
DAC11 AC6o AC8o BBTM6 cl-2
BBTM8 cl-2 UTLAC6 Ref. M10
1/3 octave band SPB spectra, cars, M64 year 0
Air pumping noise
Vibration noise
No absorp-tion dip
Portorož, Slovenia
CPXDK index at M10, year 3, 80 km/h
oRange 100 – 101.5 dB
oBest surfaces:SMA 8SMA 6+AC 8o
M10, year 3
93
94
95
96
97
98
99
100
101
102
CP
XD
K [
dB
]
DAC11 UTLAC8 AC8o SMA6+ SMA8
Portorož, Slovenia
CPXDK index at M64, year 1, 80 km/h
oRange 95.5 – 98.2 dB
o3 – 5 dB lower than M10, year 3
oBest surfaces:SMA 6+BBTM 6 Cl.2UTLAC 6SMA 6AC 6o
M64, year 1
93
94
95
96
97
98
99
100
101
102
CP
XD
K [
dB
]
BBTM8 cl-2 UTLAC8 AC8o BBTM8 cl-1 DAC11 SMA8
AC6o SMA6 UTLAC6 BBTM6 cl-2 SMA6+
Portorož, Slovenia
Texture and SPB noise spectra, M10 year 0 & 2
oAC 8o (best surface)oTexture spectra almost identical year 0 & 2,
noise increased
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
Wavelength [mm]
dB [re 1µm]
AC8o Year 0 Left AC8o Year 0 Right
AC8o Year 2 Left AC8o Year 2 Right
41434547495153555759616365676971737577
63 80 100
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
5000
6300
8000
Frequency [Hz]
dB [re 20µPa]
AC8o Year 0 AC8o Year 2
Portorož, Slovenia
Texture and SPB noise spectra, M10 year 0 & 2
oSMA 6+ oTexture spectra year 2 lower, noise increasedoTexture levels lower than for AC 8o, noise levels similaroNO simple relationship found
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
Wavelength [mm]
dB [re 1µm]
SMA6+ Year 0 Left SMA6+ Year 0 Right
SMA6+ Year 2 Left SMA6+ Year 2 Right
41434547495153555759616365676971737577
63 80 100
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
5000
6300
8000
Frequency [Hz]
dB [re 20µPa]
SMA6+ Year 0 SMA6+ Year 2
Portorož, Slovenia
MPD for 6 and 8 mm test surfaces
oMPD reduced by traffic during first ½ year (M64)
oMPD increased from year 0 to year 2 (M10, 84000 veh/day)
oMPD for test surfaces > MPD for AC 11d ref. surface
0,0
0,2
0,4
0,6
0,8
1,0
1,2
DAC11 SMA8 AC8o SMA6+ UTLAC8
Year 0
Year 2
0,00,20,40,60,81,01,2
DA
C 1
1
SM
A 6
SM
A 6
+
UT
LAC
6
UT
LAC
8
SM
A 8
BB
TM
6 C
l.2
BB
TM
8 C
l.2
BB
TM
8 C
l.1
MP
D [
mm
]
month -0
month 7
Portorož, Slovenia
Skid resistance for 6 and 8 mm test surfaces
oFriction increased by traffic during first ½ year (M64)oFriction reduced from year 0 to year 2 (M10,
84000 veh/day)oFriction for test surfaces > friction for AC 11d ref. surface
Measurements of the friction at M 10 test site
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
TP 8c SMA 6+ AC 8o SMA 8 AC 11d
August 2004 September 2006
M64
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
DA
C11
BB
TM
6 cl
-2
BB
TM
8 cl
-1
BB
TM
8 cl
-2
SM
A6
SM
A6+
SM
A8
UT
LAC
6
UT
LAC
8
month -0 month 7
Portorož, Slovenia
Summary, thin surface layers, 6 – 8 mm max
Traffic noise reduction, year 0 – 1:ore DAC 11 same age:Light 5 dBHeavy 3 dBTraffic 4 dB
ore Nord2000:Light 7 dBHeavy 4 dBTraffic 5 dB
MPD: test surfaces > AC 11d ref. surface
Friction: test surfaces > AC 11d ref. surface
Portorož, Slovenia
Recommendations
Optimize thin layers for noise reduction:AC · o, SMA ·, and BBTM · Cl.2
Pavement design:•Small, cubic aggregate•Good compaction•High built-in air void•Modified bitumen
Lifetime investigations are needed
New: Herning-27 thin layers builtSept. 2008
Portorož, Slovenia
Thank you for your attention!
For detailed information:
download DRI reports from www.roadinstitute.dk
or contact [email protected]
