1)FLYASH: A PROBLEM
OF POLLUTION AND DISPOSAL
72% of India's power plants are coal based.
These power stations generate nearly 40 million tonnes of flyash annually.
Flyash causes severe
pollution of air and water,and its disposal
gobbles up large tracts of land. Well planned programmes
for proper management of flyash are therefore being
undertaken to enhance the use of flyash in various
applications, so that our already perilously imbalanced
environment can be protected.
Recycling of Flyash
Bricks, Portland pozzolana
cement, blocks, tiles,
light weight aggregates and hollow blocks are
produced utilising flyash as raw material. Mechanised
manufacture of flyash lime bricks is a major thrust area.
The twofold aim is to utilise bulk quantities of flyash and
help bridge the huge shortfall of bricks and other
building materials required by the constantly rising
construction activity.
Advantages of flyash bricks
Several loadbearing
grades.
Savings in mortar, plastering.
Smart looking brickwork.
2)AGRO WASTE RECYCLING INTO BUILDING MATERIALS
India is primarily an agricultural country.In the absence
of organised data, exact estimates of the agricultural wastes such as bagasse,
banana leaves and stalks, saw mill waste, sisal fibre, rice husk, jute stalk
etc.,are not available, but their availability in the country is more than
500 million tonnes
per year.
Recycling Agro Waste
The building materials
industry is gainfully
utilising these wastes in a wide range of applications, many of which
can serve as timber substitutes for wood-based products. By their very nature,
fibrous wastes along with suitable binders under pressure are eminently
suitable for making several kinds of insulation boards, panels and roofing
sheets. These products can be strong, lightweight and also find aesthetic
acceptance.
3)CELLULAR LIGHTWEIGHT CONCRETE
Cellular Lightweight Concrete (CLC) has been used in over 40 countries
over the past 25 years to produce over hundred thousand
houses and apartments, apart from schools, hospitals, industrial and commercial
buildings. CLC is an air-cured lightweight concrete
with flyash as a major ingredient, that can be produced at large project sites just like traditional concrete, utilising equipment
and moulds normally used for traditional concreting.
It is especially suitable in India for low-rise loadbearing constructions
and for partitioning work in multistorey blocks.
Benefits of CLC Blocks/Panels:
Tremendous weight reduction
High thermal insulation
Optimal fire rating
Substantial material saving:
No gravel used
Little cement
Less steel in structure and foundation
Easy and fast production
No primary energy and reduced transportation costs
Boon for remote areas with only sand availability.
In view the use of flyash (33%) in CLC and this being
a good substitute of ordinary clay bricks ( which use high energy and precious
agricultural topsoil) the Govt. of India has given
special import duty concessions for specialised equipment.