Wednesday, May 6, 2009

Construction and demolition waste

Construction and demolition waste

Demolition waste
Polyurethane insulator material marked for removal of the construction site (of a residential building). This material is quite wasteful and alternatives as compressed straw could be better used instead.

Construction and demolition waste (C&D waste) consists of unwanted material produced directly or incidentally by the construction or demolition industries.This includes building materials such as insulation, nails, electrical wiring, and rebar, as well as waste originating from site preparation such as dredging materials, tree stumps, and rubble. C&D waste may contain lead, asbestos, or other hazardous substances.Much building waste is made up of materials such as bricks, concrete and wood damaged or unused for various reasons during construction. Observational research has shown that this can be as high as 10 to 15% of the materials that go into a building, a much higher percentage than the 2.5-5% usually assummed by quantity surveyors and the construction industry. Since considerable variability exists between construction sites, there is much opportunity for reducing this waste.Certain components of C&D waste such as plasterboard are hazardous once landfilled. Plasterboard is broken down in landfill conditions releasing hydrogen sulfide, a toxic gas.
There is the potential to recycle many elements of C&D waste. Often roll-off containers are used to transport the waste. Rubble can be crushed and reused in construction projects. Waste wood can also be recovered and recycled.
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, or demolition begun, before the authorities have ascertained 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.
Gallery

A bag with construction waste from a dwelling-to-be.

Rebars being thrown away at a construction site. Again, if these were to have been used or recycled by someone (eg the building company itself), A considerable sum of money could have been reclaimed.

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