ASPHALT:

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ASPHALT THE STRONG, QUIET TYPE
www.AsphaltAlliance.com
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The Decibel Scale
Discomfort
Hearing Threshold
Pain Threshold
Conversation
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The Decibel Scale
Increasing the decibel level by 10 doubles the
noise intensity!
Train
Conversation
Chain Saw
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The Decibel Scale
A reduction of 3 dB(A) is like doubling the
distance from the noise.
67 dB(A)
50 ft
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The Decibel Scale
A reduction of 3 dB(A) is like doubling the
distance from the noise.
67 dB(A)
- 3 dB(A) 64 dB(A)
100 ft
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Noise Makes News!

• Road Surface Material Can Reduce Noise
• Bituminous surfaces generally produce less noise
  than do concrete surfaces . . . Star-Tribune,
  Minneapolis, MN, March 21, 1999, pg. 6E.
• Drivers on Exeter, U.K.s A30 Complain About
  Noise from Concrete Surface, Joining Residents
  for Asphalt Resurfacing
• Western Morning News, Exeter, U.K., December 4,
  1999

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Noise Makes News!

• Residents Living Near New York Citys Long Island
  Expressway are Upset at Noise from New Concrete
  Roadbed
• Daily News, Donald Bertrand, New York City, Sept.
  20, 1999, Suburban, pg. 1
• Livonia Residents Complain of Freeway Noise
• Hundreds of people who live along I-275 . . .
  have complained about increased noise . . . since
  the state re-paved the road with concrete. The
  Detroit News, Sheri Hall, Livonia, MI, November
  3, 2000, http//detnews.com/wayne/0011/03/

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Noise Makes News!

• What can be done?
• Erect Noise Walls
• Plant Trees/Shrubs
• Surface Pavement with Hot Mix Asphalt
• Open-Graded Friction Course
• Stone Matrix Asphalt
• Dense-Graded HMA

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Noise Walls
Effective only for those not in line-of-sight.
Do not reduce noise at source.
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Noise Walls

• Effectiveness must justify expense.
• Cases
• I-40, Knoxville gt25,000/home
• I-285, Atlanta Requirements of gt 69 dB(A) and lt
  50,000/home
• U.S. 441, West Boca, FL gt 67dB(A),
  lt30,000/home, reduction of gt 5dB(A)

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What Can Be Done?

• Noise factors including vehicle type, speed, and
  tire tread are beyond control of agency.
• A recent survey shows (NCHRP Synthesis 286)
  pavement texture is most important factor in
  highway noise.
• Pavement texture can be controlled.

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What Can Be Done?

• DOTs indicate a strong need for pavement noise
  control strategies.
• Proper selection of pavement surface is the best
  method to reduce noise from pavement/tire
  interactions.

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Noise Generators

• Major noise generators of vehicles are
• engine,
• exhaust system,
• aerodynamic noise, and
• tire noise.
• (Herman, TRR 1626 McNerney, et al., TRR 1626)
• For gt 50 mph, pavement/tire noise
  dominates.(Billera, et al., TRR 1601)

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Effect of Pavement Surface

• Swedish study - pavement surface can cause a
  change of up to 15 dB(A). (Sandberg, Inter-Noise
  79, 1979)
• Noise studies in U.S. and Europe show asphalt
  surfaces quieter than PCC. (Wayson, NCHRP
  Synthesis 268)

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Effect of Pavement Surface

• Open-graded asphalt surfaces are up to 10 dB(A)
  quieter than transversely tined PCC pavements.
  (Hibbs and Larson, FHWA-SA-96-068, 1996 Jofre,
  et al., 7th Intl Symposium on Conc. Roads, 1994
  Younger, et al., FHWA-OR-RD-95-13B, 1994)
• A decrease of 3 dB(A) is significant. Has the
  same effect as doubling distance.

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Effect of Pavement Surface

• OGFC is the quietest surface type. (Wayson, NCHRP
  Synthesis 268)
• SMA has also proven to be a quiet surface.
  (Wisconsin DOT, 1993)
• Dense graded HMA surfaces are quieter than PCC
  pavements.(Hibbs and Larson, Report
  FHWA-SA-96-068, May 1996)

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Summary

• Highway noise is important to the public.
• Small changes in dB level are noticeable.
• Increase of 10 dB(A) doubles noise
• Decrease of 3 dB(A) is like doubling distance

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Summary

• Noise walls can work, but
• They are expensive.
• They dont work in all types of terrain.
• Source of noise is still there.
• Asphalt pavements can reduce noise up to 10
  dB(A).

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Summary

• Asphalt pavements for noise reduction in order of
  effectiveness
• OGFC
• SMA
• Dense-Graded HMA
• (NCHRP Synthesis 268)

Hot Mix Asphalt
PCC