Civil Engineering Reference
In-Depth Information
Fig. 1.1
Typical concrete
mix
mechanical and durability properties of concrete and also indirectly reduce the
emission of CO
2
. Nanotechnology can provide huge opportunities towards gaining
sustainability in concrete preparation. Improved understanding of nanostructure of
cement hydration product, the only binding phases in concrete using nanotech-
nological tools, the use of nanomaterials such as nano silica, nano alumina and
nanofibres in concrete preparation, the use of photo-catalysts such as nano TiO
2
for
self-cleaning of concrete products, and the use of nanotechnology to monitor the
performance during service life of concrete, are some of the recent inventions,
which definitely decrease the environmental impact of concrete (Mukhopadhyay
2011
). However, the toxic effect of nano-based products in human health during
manufacturing and the service life of the resulting concrete products must thor-
oughly be investigated before their applications.
1.5 Sustainability in Concrete by Innovation in Concrete
Constituents
Concrete mainly consists of at least three constituents: cement as a binding
material, aggregates, the major part of concrete (normally accounting for 70-75 %
of its volume) and water. A typical concrete composition is shown in Fig.
1.1
.
Each constituents of concrete has its own environmental impact; however, the
sustainability of concrete as a material is strongly influenced by the cement and
aggregate industries. The sustainability in water use in concrete has also become a
big issue recently due to the huge consumptions of potable water during concrete
preparation as well as the scarcity of potable water faced all over the world.
Sustainability in water, cement and aggregate use in concrete preparation is
highlighted in the remaining sections.
