Guidelines for silent roads in NL

Guidelines for silent roads in NL
Jacob Groenendijk MSc PhD, Walter Gerritsen BSc
KOAC-NPC Dutch Road Research Laboratories
Ronald van Loon MSc, GijsJan van Blokland PhD
M+P consulting engineers
Message
Silent pavements are more costly
than conventional pavements,
but they mostly are the cheapest
traffic noise mitigation measure!
Audio demonstration
tyre pavement noise
0 dB(A)
Dense
Asphalt Concrete
(“reference”
Normal tyre
Silent tyre
-2 dB(A)
Thin Silent
Surfacing
-4 to -5 dB(A)
-6 dB(A)
consulting engineers
-6 dB(A)
2-layer
Porous Asphalt
-7 dB(A)
ZOAB met
-8 dB(A)
Ultra rubberen
silent
poreuze
rubbertoplaag
pavement
-9 dB(A)
Contents
•
•
•
•
Overview of silent pavement types
Dutch acoustical characterisation
What is (not) applicable
How to choose the right type and product;
service life expectancy
• Boundary conditions for construction, e.g.
season, crossings, etc
• Maintenance?
• Type of construction contract?
Overview silent pavements
• Silent asphalt
–
–
–
–
Porous Asphalt (PA)
2-layer PA (2PA)
Silent Thin Surfacings (STS)
(SMA)
• Silent block pavements
• Silent PCC
– Porous Concrete
– Optimised texture
Choice of (silent) pavement (1)
• Choice between asphalt, concrete or blocks
mostly for conventional reasons (subgrade
settlements, cables and ducts, traffic speed,
looks)
• Asphalt generally more silent than concrete or
blocks
• Choice of pavement influences traffic speed,
hence traffic noise (10 km/h faster => 1 to 3 dB
more noise)
Choice of (silent) pavement (2)
• What is needed/desired acoustically?
– Traffic: cars/trucks, speed
• What is technically possible (durable)?
– Torsion, (clogging)
• What is economically feasible?
– Service life, cost comparison with noise
barriers or insulation of houses
Choice of (silent) pavement (3)
Type of road
Max.
speed
(km/h)
Porous
Asphalt
2-layer
Porous
Asphalt
(PA)
(2PA)
Texture
optimised
cement
concrete
(TOCC)
Silent
Silent
thin
block
surfacing paving
(STS)
Motorway
120
+
+
+
Rural trunk road
100
+
+
+
+
Rural distributor road
80
+
+
+
Rural lower class
road
60
+
Urban trunk road
70
+
Urban distributor
road
50
+
Urban lower class
road
30
(SBP)
+
+
How to get a silent road?
80
dense and smooth
open
70
thin absorbing
thick absorbing
3
60
1
2
4
50
1:improve texture
4:’tune’absorption
2:reduce flow resistance
3:add acoustic absorption
frequency [Hz]
00
50
00
40
50
31
00
25
00
20
00
16
50
12
00
10
80
0
63
0
50
0
40
0
31
5
25
0
20
0
16
0
12
5
ax
40
LA
m
80 km/h passage level at 7,5 m [dB(A)]
dense and rough texture
Acoustic characterisation in NL
“Cwegdek” = noise reduction when new,
relative to “reference”
• average over 5 sections
• noise reduction measured by SPB at 5(!) m
height
• “reference” is table of SPB-values, based on
DAC 0/16 en 0/11 (1-2 years old)
• different vehicle types and speeds
• both “pavement types” and individual products
C_wegdek cars
5
gewone elementen
(niet keper)
4
3
elementen
keperverband
2
fijngebezemd beton
oppervlakbewerking
uitgeborsteld beton
C_wegdek [dB(A)]
1
0
geoptim. uitgeborsteld
beton
stille elementen
-1
-2
SMA 0/6 (SMA-NL 5)
dunne deklagen A
-3
ZOAB 16
dunne deklagen B
-4
-5
-6
2L ZOAB (4/8)
-7
2L ZOAB fijn (2/6)
-8
30
40
50
60
70
80
snelheid [km/u]
90
100
110
120
130
C_wegdek trucks
5
gewone elementen
(niet keper)
4
3
elementen
keperverband
C_wegdek [dB(A)]
2
fijngebezemd beton
1
stille elementen
SMA 0/6 (SMA-NL 5)
0
-1
uitgeborsteld beton
oppervlakbewerking
dunne deklagen B
geoptim.
uitgeborsteld beton
-2
-3
dunne deklagen A
-4
ZOAB 16
-5
2L ZOAB fijn (2/6)
-6
2L ZOAB (4/8)
-7
-8
30
40
50
60
70
80
snelheid [km/u]
90
100
110
120
130
Choice of (silent) pavement (1)
• Porous pavements (>20% voids)
– Only >70 km/h (cleaning effect of car tyres)
– Not with heavy pollution
– Critical under torsional traffic
– Take care of drainage and weed growth
• STS (Silent Thin Surfacings)
– Critical with heavy pollution
– Critical under torsional traffic
Expectancy of service life
• NB! Strongly dependant on traffic (type, loads,
speed, torsion), conditions and construction quality
Pavement type
Technical
Acoustical
PA (motorways)
7-16 (11)
same?
2PA(>70 km/h)
5-10 (7)
same?
STS
5-15? (8?) ?????
SMA
15-25
same?
STS: service life,
noise and porosity
levensduur
(jaar)
Service
life [years]
15
7
6
Service life
10
5
4
3
Noise reduction
5
2
1
0
0%
5%
10%
15%
20%
0
25%
H o llecontent
ruim te
Void
NB! General estimates only, exceptions exist
(dB(A))
Noisegeluidreductie
reduction [dB(A)]
8
Acoustical deterioration over time
15
Thin Silent Surfacings
(STS)
kort
Newna oplevering
2 years
twee
jaarold
na aanleg
5 years
old
vijf
jaar na
aanleg
5
lmv50
50 km/h
km/u [dB(A)]
Noise geluidreductie
reduction, cars
[dB(A)]
<0
0 - 0.5
0.5 - 1
1 - 2.5
1.5 - 2
2 - 2.5
2.5 - 3
3 - 3.5
3.5 - 4
4 - 4.5
4.5 - 5
0
>5
aantal [-] [[-]
# sections
10
Acoustical deterioration over time
70
sound level (SPB) [dB(A)]
68
66
64
t h in s u rfac e l ay e rs
d ou ble la y e re d p o ro u s a s p ha lt
s ilen t b lo c k p a ve m e nt
d en s e a s p ah lt c on c re t e
62
60
0
1
2
3
4
tim e o f th e m e a su r e m e n t [y e a r s]
5
6
“Effective noise reduction”
dB(A)
?
+2
?
0
conventional
?
“reference
?
e.g. ca. +0.5 dB/yr
example STS
-4
time
8 yr? or
0,5*Tconv
Tconv ca. 16 yr?
Acoustical deterioration over time
8.5
CPX-meting 50 km/h
geluidreductie 2006 [dB(A)]
• initially high
noise reduction
does not imply
largest
deterioration
(noise
increase)!
CPX-meting 80 km/h
5.5
2.5
-0.5
-0.5
2.5
5.5
geluidreductie 2004 [dB(A)]
8.5
Acoustical deterioration over time
• Reasons for acoustical deterioration
– Hardly texture related, acoustical effects of
ravelling are small at 6mm nominal aggregate
size
– acoustical deterioration mostly related to
absorption characteristics (“clogging” of
pores, but cleaning does not help for STS)
Clogging of STS
Blue: near side
wheel path
Red: between
wheel paths
0
5
10
15
Void content [%]
20
25
Durability silent asphalt
• Wet friction
+ polishing-resistant aggregate (high PSV)
• Rutting
+ gap graded stone skeleton (and polymer
modified bitumen)
Silent asphalt on
roundabout??
• ravelling
+ polymer bitumen
+ good aggregate
– high porosity
NO !
Meetvakken CROW
• Tweelaags ZOAB
–
–
–
–
7 vakken
2/4 en 4/8 toplaag
aanleg 1993 – 1999
monitoring 2001 – 2006
• Dunne Geluidreducerende Deklagen (DGD)
–
–
–
–
9 vakken
4 producten
aanleg 2003 – 2004
monitoring 2004 – heden
Stroefheid Tweelaags ZOAB
0,6 0
0,5 5
f50 ( -)
0,5 0
1: 2/4 , 1999
2: 4/8 , 1993
3: 4/8 , 1994
4: 2/4 , 1997
5: 4/8 , 1999
6: 4/8 , 1993
0,4 5
7: 4/8 , 1997
0,4 0
0,3 5
0,3 0
na ja ar 20 01
sep te mbe r 200 2
se ptemb er 20 03
n ove mbe r 200 4
j un i/jul i 20 05
Mee tdatum
• Nr 3: rafeling-corrigerende maatregel in 2004
• NB! grote verschillen in ouderdom
me i/au g 20 06
Textuur Tweelaags ZOAB
1,6
1,5
1,4
1,3
1,2
1: 2/4 , 1999
2: 4/8 , 1993
3: 4/8 , 1994
4: 2/4 , 1997
5: 4/8 , 1999
6: 4/8 , 1993
7: 4/8 , 1997
MPD (m m)
1,1
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
na ja ar 20 01
se ptemb er 20 02
se ptemb er 20 03
no vem ber 2 00 4
j un i/ju li 20 05
Me etdat um
• Nr 3: rafeling-corrigerende maatregel
in 2004
• NB! grote verschillen in ouderdom
me i/au g 200 6
Stroefheid DGD
Stroefheid (RAW 150) dunne deklagen, rechter wielspoor
0.60
0.55
A 2004
A 2004
A 2004
0.50
f50 (-)
C 2003
A 2003?
D 2004
0.45
B 2003?
A 2003
C 2003
0.40
0.35
jan 2005
juni/juli 2005
aug/sep 2006
juni 2007
• Seizoensinvloed
• Grote spreiding binnen product
• Verschil tussen “jaargangen”, wijzigingen in product?
Textuur DGD
0,8 0
0,7 5
0,7 0
0,6 5
1: Microflex 0/6
7: Microflex 0/6
8: ZSA-SD
9: Microflex 0/6
10: Microflex 0/6
11: Dubofalt ZS
12: Microflex 0/6
13: Dubofalt ZS
14: Kon wé stil
MPD (m m)
0,6 0
0,5 5
0,5 0
0,4 5
0,4 0
0,3 5
0,3 0
n ov / d ec 20 04
j un i/jul i 20 05
Me etdat um
a ug ustus 2 006
Points of attention:
Design
• Avoid manual laying!
• SMA where torsion (crossroads, entrances &
exits, along parking lanes)
• “Soft” transverse joints (changing mix ‘on the fly’)
• Quality underlying structure !!
– Assessment and analysis (bearing capacity, cracks,
ravelling, unevenness, potholes, ..), necessary repairs
• Also renew binder layer(?)
• Noisy foreign objects (e.g. bridge joints,
manhole covers, road markings)
Points of attention:
Construction
• Preparation old pavement
– Repairs
– Tack coat
• Low heat capacity
• Weather conditions!
• Continuous production and
supply
• Joints
• (Manual laying, if any)
• Initial friction (wet & dry)
Aandachtspunten
kwaliteitscontrole
• Functionele eigenschappen
• Zo weinig mogelijk of geen
boorkernen
• Geen eis verdichtingsgraad
– referentiedichtheid
– Verbrijzeling
• Wel eisen HR
(“conform ontwerp”)?
• Samenstelling (hoppermonsters) conform opgave?
• Steenslag
• Hechting?
Points of attention:
Management and Maintenance
• Management:
– Extra attention for winter maintenance (de-icing)
– Monitoring of noise reduction?
• Maintenance for acoustical reasons?
– Boosting of noise reduction (yet??) impossible
(cleaning has no effect)
• Maintenance for technical reasons
– Extension of service life or local repairs (still??)
very difficult
– Renew wearing course (and binder too?!)
Recyclability
• A challenge in the future to recycle single-sized
RAP with PMB, especially in new (silent)
wearing courses….
(But we will cross that bridge when we come to
it ….)
Contracts (1)
• Make explicit requirements for noise
reduction
– SMART: specific, measurable, acceptable,
realistic, time-dependant
– For relevant traffic type and speed
– Preferably based on acceptance testing
– Not only initial reduction, but also after time
(e.g. 2-3 years)
– BE REALISTIC, both in dB and in years
Contracts (2)
• Requirements for initial friction (wet & dry)
• Innovative contracts?
– In principle possibility for clear division of
responsibilities, but:
– Little experience with long term performance,
so realistic (fair) requirements are still difficult
– Legal formulation of warranty conditions
– Legal risks larger than technical risks?
Checklist applicability
Silent Pavements (1)
• Design
–
–
–
–
–
quality of underlying structure
desired noise reduction (traffic type and speed!)
drianage
friction
durability
• traffic intensity
• torsion
– (no) manual laying
Checklist applicability
Silent Pavements (2)
• Construction
–
–
–
–
planning / season
preparation old pavement (repairs)
initial friction (wet & dry)
durability
• Management and maintenance
– noise reduction and drainage
– winter maintenance (de-icing)
– durability
Conclusions
• Silent pavement often the most cost
effective noise mitigation solution, but:
• Be realistic!
• Take into account:
–
–
–
–
–
Noise increase over time
Shorter technical service life (than trad. pav.)
Construction is critical (design, planning)
Higher construction costs (than trad. pav.)
Higher maintenance costs (than trad. pav.)
Message
Silent pavements are more costly
than conventional pavements,
but they mostly are the cheapest
traffic noise mitigation measure!
Thank you for your attention!
Questions?
[email protected]
Mob: +31 644 83 65 19
• STS not applicable without strengthening!
• and why should you?
• STS not applicable without strengthening!
• and why should you?
• Width problem remains!

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