17-08-2012, 11:48 AM
RECYCLED AGGREGATES
RECYCLED AGGREGATES.pptx (Size: 1.36 MB / Downloads: 39)
Recycling is the act of processing the used material for use in creating new product.
Usage of natural aggregate is becoming intense.
Recycled aggregates can replace natural aggregate.
Recycled aggregates are obtained from construction and demolition debris.
HISTORICAL BACKGROUND
From the time of Romans, the stones from previous
roads were used for rebuilding of roads.
It has been used in Australia for the last 100 years.
Extensive research started in 1945.
Nixon made first effort in 1977.
State -of-the-art document by Hansen in 1992.
INTERNATIONAL STATUS
IN EUROPEAN UNION
IN UK
IN HOLLAND
IN NETHERLANDS
IN GERMANY
IN FRANCE
IN JAPAN
IN HONG KONG
IN USA
INDIAN STATUS
Quantum of solid waste – 48 million tonnes per annum.
Construction industry waste – 12 to 14.7 million tonnes.
Due to excessive dumping shortage of place for further dumping.
Project on recycling and reuse of C & D wastes by SERC,ghaziabad.
Use of RA in Indian scenario.
What are recycled aggregates ?
Why recycled aggregates ?
Sources of recycled aggregates ?
What are recycled aggregates ?
Recycled aggregates are the aggregates produced from the processing of previously used construction materials such as concrete or masonry.
Recycled aggregates consists of hard, graduated fragments of inert mineral materials, including sand, gravel, crushed stone, slag, rock dust, or powder.
Why recycled aggregates ?
Due to rapid growth in population and urbanization, the natural resources are depleting.
High cost of good quality crushed aggregates, as compared to Recycled aggregates.
Shortage of dumping sites has resulted in sharp increase in transport and disposal costs.
An enormous increase in the quantity of waste materials and the shortage of dumping sites.
Sources of recycled aggregates ?
Construction and demolished waste generated due to natural disasters, for future development the old buildings are replaced by new ones, and war inflicted damages.
Crushing of Portland concrete pavement
Tested specimens from laboratory.
Concrete from ready mix concrete plants and precasting units.
Worn out rail ballast.
CONCLUSION
Recycling and reuse is an appropriate solution.
Use of recycled aggregates prove to be valuable.
There is a need for modifying codes, specification
The subject of use of recycled aggregates in India should be given importance