LOW NOISE THIN SURFACE COURSE
As the traffic volumes within urban areas increase, this poses strong political pressures to reduce traffic noise, thus improving the urban population’s standard of living.
Ultraphone is a low noise surface course material, developed by Jean Lefebvre (UK) which meets every expectation of those living in the vicinity. It combines the benefits of exceptional noise reducing properties with excellent skid resistance characteristics.
- Substantial reduction in rolling noise
- Excellent skid resistance
- Reduced spray in wet weather conditions
- Perceived traffic reduction of ≥ 50%
- Installed at depths of between 20 and 30mm
THE WINNING FORMULA
Ultraphone efficiently and sustainably combats tyre noise (rolling noise) pollution generated by moving traffic. Its design lowers the risk of long-term silting up, unlike porous asphalt; therefore, its acoustic performance is maintained. Based on these intrinsic properties it is surfacing best suited for the construction and maintenance of urban and suburban pavements.
In addition to comfort and safety, Ultraphone offers a homogenous surface which is aesthetically pleasing.
Ultraphone is typically applied using conventional paving equipment. An integral part of the system is the use of a bond coat. The application rate of this is adapted to suit the type of substrate; thus ensuring an excellent bond and waterproofing characteristics prolong the service life of both the surface and the underlying pavement.
EXCELLENCE ACROSS THE BOARD
Developed in France during the 1980’s Ultraphone uses high performance polymer-modified bitumen, which have high cohesion, low thermal sensitivity and excellent resistance to aging. Different degrees of modification make it possible to adapt the choice of binder to the performance requirements, nature and characteristics of the substrate, traffic loading and climatic conditions.
Ultraphone’s 0/6mm gap-graded formulation, along with the binder properties give the material excellent resistance to deformation, along
with acoustic and skid resistance characteristics.
Ultraphone is 100% recyclable, thus reducing the amount of material being sent to landfill.
The special formulation provides Ultraphone with its low rolling noise and excellent skid resistance properties.
Optimised Noise Reduction
The standard analysis of measuring road noise is the Statistical Pass-By method. The principle is to measure the emitted noise a person at the side of the road would hear as various vehicle types pass by, taking account of the amount of noise absorbed by the road surface. For a particular surface, the volume of noise will depend on vehicle speeds and the combination of vehicles in the flow.
Noise is measured in units called decibels (dB). The human ear is not equally sensitive to all frequencies, so a measure known as ‘A’ weighting is used to give dB(A). It is a log scale, so a decrease of 3dB(A) is equivalent to the halving the traffic, or doubling the distance away from the source.
Surveys have shown that even with traffic speeds of 30mph, the reduction on noise with Ultraphone compared to an adjacent section constructed with standard 0/14 Thin Surfacing was 5.7 dB(A).
This is a very significant and noticeable improvement, equivalent to reducing the traffic by 75%.
Ultraphone is capable of providing adequate friction at both low and high speeds even though its in-service surface texture may be relatively low when measured by conventional techniques.
This is due to the 0/6mm gradation, which provides a higher proportion of aggregate in the road/ tyre interface, thus improving the grip.
SCRIM analysis has indicated that Ultraphone consistently outperforms other thin surface course materials produced with larger size aggregates from the same source.
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