Geotechnical Use of Waste Material

Waste Reduction

Many urban centers in India are facing problems of finding adequate land for disposal of waste. Disposal of waste in landfill is not a sustainable solution in long term because of limited availability of land space.
        The most suitable long term sustainable solution is to reduce the quantity of waste being produced and eventually become a 'zeo waste' society. 
         Industrial waste reduction can be achieved through adoption of efficient and clean technologies which produce the same quantity with smaller waste and also by recycling or through re-use of waste material generated.

Use of Waste Material in Geotechnical Construction 

Soil is used as construction material in various applications such as earth dams, for road and rail embankments, for filling of low-lying areas, for embankments of canals and lakes, for backfilling behind retaining structures etc. If soil could be replaced by waste material in some of these applications, not only would waste material not have to be disposed off but it would result in the following added benefits-

1. Saving of valuable top soil; suitable for agriculture
2. Reduction in number of depressions created due to excavation of soil.

Waste characteristic for Soil Replacement 

Not all wastes are suitable for use in Geotechnical construction works. Following characteristics are essential-
  1. Should not be classified as hazardous material,
  2. Should not have any biodegradable component,
  3. Particles should not be soluble, not volatile and not to be susceptible to disintegration,
  4. Should not exhibit a high degree of heterogeneity.
  5. Should not have the potential of harming the ground water quality.

Some waste material that meet the above criteria and can be considered for use in geotechnical construction are as follows:

  1. Coal ash available in ash ponds
  2. Mine tailing available in tailing ponds 
  3. Mining overburden 
  4. Construction and demolition waste 
  5. Waste discarded by marble, slate, china clay industries etc.