Civil Engineering Reference
In-Depth Information
1.2 Sustainability in Construction Materials
The construction industry, one of the largest industries in the world, is notorious
for having a major role on the emission of CO
2
into the atmosphere. Nowadays,
the pace of development of this industry is increasing enormously all over the
world especially in the developing countries due to rapid economic and industrial
developments and consequent development of infrastructures and standard of
living. As an example, currently, the construction industry is the second largest
industry in India and the total investments in this sector account for nearly 11 % of
the total gross domestic product (Construction Industry in India
2008
). Similarly,
the construction industry in China has been experiencing consistent growth for a
long time and each year China spends nearly 16 % of its gross domestic product in
this sector (China construction industry no date). By the end of 2001, about 36.69
million people in China worked on the construction sector. The construction
industry is responsible for 7 % of total employment in the European Union (EU)
and in the EU, the US and Japan combined, it employs more than 40 million
people (OECD
2008
).
The residential sector consumes huge amounts of energy all over the world. The
energy used in the construction sector comprises direct use at the construction site
and indirect energy used in the manufacture of the building materials. In the EU,
about 40 % of total final energy is consumed by the residential and tertiary
building sectors (Koukkari et al.
2007
). According to Joseph and Tretsiakova-
McNally (
2010
), building construction in the world consumes around 25 % of the
global annual wood harvest; 40 % of stone, sand and gravel; and 16 % of water
and also generates 50 % of the global output of greenhouse gases and agents of
acid rains. The rapid expansion of this sector is creating a huge environmental
problem all over the world and therefore recently several initiatives have been
taken to tackle such problems.
To evaluate the environmental impact of construction materials, several issues
need to be considered, namely collection, treatment and production of raw
materials, construction, service life and demolition and disposal. In the whole
process of construction, service life of the building and its demolition, not only
huge amounts of energy of all sectors are consumed but also huge amounts of CO
2
emissions are created. These activities also consume huge amounts of most non-
energy-related resources, create high volumes of waste and are responsible for
enormous pollution in the atmosphere, soil and water. The uses of energy and the
emission of CO
2
take place at various steps, such as raw material extractions,
transportation, manufacture, demolition, service life and waste processing.
Table
1.1
shows a typical example of calculation of the emitted amount of CO
2
into the atmosphere at the various steps of a building life cycle (BIS
2010
).
Thus, by considering the size, importance, resources use and environmental
impact of the construction industry, it is necessary to produce sustainable con-
struction materials with increasing service life but minimum maintenance future
needs. Sustainability in construction is also inevitable due to stringent regulations
