Civil Engineering Reference
In-Depth Information
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13.9
Colour measurements in CIELab colour space.
environment can be created artifi cially or it is possible to expose some
specimens directly to urban atmosphere. In the latter case, since experimen-
tal conditions (humidity, temperature, irradiation) cannot be chosen and
regulated, it is fundamental to have a monitoring station close to the expo-
sure site, from where atmospheric data can be obtained. It is then possible
to correlate them with the colour measurements, the most relevant param-
eters being the amount of radiation reaching the surface during the day and
the time of wetness, which is closely correlated to the number of rainy days.
As for the interpretation of data, a lower colour change in time is expected
from a self-cleaning material. Moreover, if the soiled surface of a photoac-
tive material returns towards its original colour right after a rainy event,
and the same trend is not observed in a similar 'blank' material (without
TiO
2
), then this behaviour will be due to the onset of self-cleaning (Dia-
manti
et al.
, 2008).
13.5.3 A case study of life cycle assessment
A life cycle assessment (LCA) of TiO
2
-containing coatings for concrete
pavements was performed by Hassan in 2010. The author assumed that an
improvement in air quality cannot be used as the only criterion for the
complete evaluation of a material that should be considered sustainable, as
critical environmental factors may be omitted. Therefore, a life-cycle inven-
tory (LCI) was performed to quantify the energy, abiotic raw material
inputs and emission from cradle to grave. A Building for Environmental
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