Green Living

It’s all in the material

In most European countries the government or local authorities often make rules about how much waste should be sorted before it is hauled away to landfills or other waste treatment facilities. Some hazardous materials may not be moved before the authorities ascertain that safety guidelines and restrictions have been followed. Among their concerns would be the proper handling and disposal of such toxic elements as lead, asbestos or radioactive materials.

It is time that India made a beginning in scientific re-cycling of construction waste as a norm as the number of constructions have amplified to gargantuan proportions, says Chandrashekar Hariharan, Co-founder of BCIL-ZED Homes, the green homes builder who spoke to The Hindu-PropertyPlus about construction material that plays a major role on environment.

Is there a data on how much of construction activity goes on in Bangalore/Karnataka in a year?

There is no organised data available since much of such construction is in the private sector and among builders who are largely unlisted companies. However if you go by the figures that emerge from home finance companies the quantum of new homes bought in a year is about 15,000 to 18,000. Or about 16-20 million sq. ft of homes annually. By deduction, over a cycle of 3 years, you end up having the building industry vying for this cake of 20,000 homes.

How much can using rubble or debris make sense to restricting the use of brick & mortar?

Construction today has moved largely away from bricks, to use of solid concrete blocks. About half the market has shifted further to hollow blocks with greater compaction strength and claiming 60 per cent less materials than the conventional blocks. Without much hoopla the building industry has quietly moved to greater efficiency in material profiling for construction.

Use of rubble, concrete debris and demolition debris is pretty extensive. The BBMP has been trying its best to get builders to dispose of such construction debris in a half-a-dozen dump yards across north and east of the city. Such debris is pulverised and reused for concrete. About 100-150 tonnes a year of such construction waste gets recycled.

What is the science behind using old material and what are the economics that work out here?

If we talk of ‘old’ concrete, the dimensional stability they offer for bonding is low. They cannot be used in large quantities unless you blend in small and right proportions to fresh concrete. And as for the economics, sadly given cost of collection and transport, such debris costs nearly the same as freshly extracted stone aggregate and cement.

The deeper challenge therefore lies elsewhere - cost of such mined materials is still extraordinarily low and any increase in price will make housing even more expensive than it is today! The bad news is that over the next 15 years, we will have about 2.5 times more construction than all of what exists as buildings today!

Any idea about well known buildings in Bengaluru that have used old material?

None. There are isolated and inspiring examples of such work with recycled and reclaimed materials, but of metals and wood. They are so far and few between that they don’t count. ZED Habitats has attempted such reclaim-based architecture with a restaurant, Kanua, off Sarjapur road.

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Printable version | Nov 27, 2020 5:29:46 AM | https://www.thehindu.com/features/homes-and-gardens/green-living/its-all-in-the-material/article7285924.ece

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