CONCRETO & Construções | 59
single-layer solution to approximately
99 dB(A), which brings it into a com-
parable category as a stone mastic
asphalt with aggregates of 10 mm
(SMA-C). The average noise level for
SMA-C, calculated from a total of 70
measurements, both newer and older
pavements, was 99.6 dB(A).
The double-layer process, simi-
lar to the Austrian technique but
applied for continuously reinforced
concrete pavement (CRCP), has
also been used in Belgium. Noise
measurements show that the noise
level drops another 0.5-1 dB(A).
In 2011, the Flemish Agency for
Roads and Traffic acquired a CPX-
trailer aiming for a systematic ex-
ecution of noise measurements on
motorways and regional roads. In
Wallonia measurements were also
done on newly built road sections.
The diagram in Figure 10 gives an
overview of the results of a series of
measurements on concrete roads
(CPX with SRTT-tyre for light vehi-
cles at 80 km/h in dB(A); measure-
ments done in 2011-2012, in 2013
for N19g).
The red bars represent trans-
versely grooved surfaces, the blue
are single layered and the green
double-layered exposed-aggregate
concrete surfaces.
These measurements show that
low-noise concrete surfaces are
perfectly possible, both in a single
and a double layer concept. The
noise performance of the surface
of a double-layered CRCP is equiv-
alent to that of a stone mastic as-
phalt wearing course. For a SMA
with aggregates of 10 mm, the
average noise level for newly built
pavements (maximum 2 years old
- CPX with SRTT-tyre for light vehi-
cles at 80 km/h in dB(A)) amounts
to 98.7.
It should be noted that for the dif-
ferent types of exposed aggregate
concrete surfaces, the skid resis-
tance requirements were easily met,
both for the new and the older ones
((BRIESSINCK & RENS (2009)).
u
Figure 9
E313 Herentals-Grobbendonk: double-layer exposed-aggregate concrete
with top layer 0/6.3
Noise levels measured with CPX act 80 km/h: 98.5 dB(A) for a truck tyre
and 98.5 dB(A) for a passenger car tyre
u
Figure 10
Results of noise measurements on Belgian motorways
u
Figure 11
Longitudinal tining of fresh concrete in Illinois, U.S.
