Civil Engineering Reference
In-Depth Information
'higher' goals; in particular, the 7th UN Millennium Goal related to envi-
ronmental sustainability should be a major focus of attention. Consequently,
the construction industry should also be at the core of the R&D efforts in
nanotechnology: as one of the largest and most active sectors in the world,
it will continue to grow at a rapid pace over the coming decades, and most
importantly, it has a very high environmental impact, being responsible for
the depletion of large amounts of non-renewable resources and for carbon
dioxide gas emissions.
Concrete is the most widely-used construction material on Earth, cur-
rently used at a level of about 10 km
3
/year (Gartner and Macphee, 2011),
compared to 2 km
3
for fi red clay, 1.3 km
3
for timber, and 0.1 km
3
for steel
(Flatt
et al.
, 2012). These astonishing fi gures show the importance of con-
crete in the context of material effi ciency (Allwood
et al.
, 2011). The main
binder of concrete, Portland cement, is responsible for almost 80% of the
total CO
2
emissions from concrete, which in turn make up around 6-7% of
the planet's total CO
2
emissions (Shi
et al.
, 2011). This is particularly serious
in light of current concerns around climate change and, more worryingly
still, demand for Portland cement is expected to increase by almost 200%
between 2010 and 2050, reaching a level of 6000 million tons/year (Pacheco-
Torgal and Jalali, 2011). Nanotech research is therefore crucial in helping
to identify methods to make concrete more environmentally friendly.
Another relevant aspect of the high environmental impact of the con-
struction industry relates to the high energy consumption in buildings
(accounting for approximately one third of the world's energy consump-
tion) which is responsible for a signifi cant proportion of global greenhouse
gas emissions. In Europe, buildings are responsible for more than 40 percent
of energy consumption and greenhouse gas emissions (Lechtenbohmer and
Schuring, 2011), and energy effi ciency is an issue of crucial importance. The
recasting of the Energy Performance of Buildings Directive (EPBD) was
adopted by the European Parliament and the Council of the European
Union on 19 May 2010. The recast set 2020 as the deadline for all new
buildings to be 'nearly zero energy'; for public buildings, the deadline is
even sooner - the end of 2018. Technologies and methods to improve energy
effi ciency (Clements-Croome, 2011) are therefore required to ensure eco-
effi cient construction.
1.3
Outline of the topic
The key role that nanotechnology has to play in the development of a more
eco-friendly type of concrete is the basis for several chapters in the fi rst
part of the topic, which looks at infrastructural applications (Chapters 2-7).
Chapter 2 covers the experimental and theoretical advancements in the
fi eld of nanotechnology; these should allow a greater understanding of the
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