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Sustainable
concrete for the 21st century - Concept of strength
through durability
R.N.
Swamy
The
world is passing through difficult and troubled times,
and we live in a rapidly changing world. The construction
industry is facing many challenges - global warming,
climate change forces, and the capability to achieve
sustainable development and economic progress without
damaging our environment. The concrete industry in
particular faces further challenges. There is extensive
evidence to show that concrete materials and concrete
structures all over the world are deteriorating at
a rapid rate, and that we are unable to ensure their
long-term durable service life performance. To confound
this situation, we are also faced with an urgent need
to regenerate our infrastructure systems if we are
to eradicate poverty and provide a decent quality
of life for all the people of the world. This paper
shows that the current emphasis on high strength and
very high strength, and the design philosophy of durability
through strength for concrete materials and concrete
structures is fundamentally flawed. It is this misleading
concept and vision that is primarily responsible for
the lack of durable performance of concrete in real
life environments. To change this scenario, this paper
advocates that concrete materials must be manufactured
for durability and not for strength. It is shown that
this concept of strength through durability can be
achieved through careful design of the cement matrix
and its microstructure. If concrete is to be an eco-friendly,
and sustainable driving force and construction material
for social change, the need is to produce durable
concrete with strengths of 30 to 60 to 80 Mpa rather
than very high strength concrete without an assured
durable performance.
Use
of industrial wastes for sustainable cement and concrete
constructions
A.K.
Mullick
Construction
plays a vital role in all aspects of societal and
economic development. An overall balance between industrial
development, enhancing the quality of life by providing
food, health, housing, education and gainful employment
without damaging the ecological health of the planet
and the environment we live in, have become imperative.
Construction activities have to be carried out to
ensure well-being and prosperity of the citizens and
society, without disturbing the delicate balance of
the eco-system and the environment. In other words,
constructions have to be 'sustainable'.
Sustainability
- Challenges and solutions
N.
Subramanian
Several
factors, which are interactive in nature, are affecting
as well as threatening the existence of our planet
Earth. They include overpopulation and urbanisation
(which have multitude of effects), transportation
in cities, energy use and global warming, excessive
waste generation and subsequent pollution of air,
water and soil, and limited supply of resources. A
brief discussion about these challenges is provided
and some solutions are given. The building industry
consumes about 40 percent of the extracted materials
and is responsible for 35 percent of CO2 emissions.
Green and smart buildings will substantially impact
the energy consumption and volume of emissions. Life
cycle analysis of building materials and life cycle
management of products are necessary in order to select
the materials for high performance green buildings.
Concrete with cementitious materials such as fly ash,
silica fume and slag can be used to build such sustainable
constructions.
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