APPLICATION OF CONSTRUCTION DEMOLITION WASTE

BY:AKSHAY R MANOHAR

CCTNMAMIT-NITTE

Demolition and

INDRODUCTION:

• Construction waste consists of unwanted material produced directly or incidentally by the construction or 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.

• Construction waste may contain lead, asbestos, or other hazardous substances must be removed.

• 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 assumed by quantity surveyors and the construction industry. Since considerable variability exists between construction sites, there is much opportunity for reducing this waste.

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• At the end of a building’s life, demolition generates large amounts of materials that can be reused or recycled, principally wood, concrete and other types of masonry, and drywall.

• Rather than demolish an entire building, consider “deconstructing” all or part of the structure. Deconstruction is the orderly dismantling building components for reuse or recycling.

Diverting construction and demolition materials from landfills.

• The good news is that many construction and demolition (C&D) materials are highly reusable or recyclable. The bad news is that many of these materials are still going to landfills. Like other recycling efforts, there are more management options for C&D debris that isn't mixed with other waste, so it's important to separate reusable or recyclable materials from other debris when possible.

Materials Separation

• Containers for material recycling must be set up on site and clearly labelled. Construction personnel must be trained in material sorting policy, and bins must be monitored periodically to prevent waste mixing as a result of crews or passersby throwing trash into the bins.

• Some materials will require bins or storage that protect from rain. Other bins may be locked to prevent tampering.

Dumping and separation.

Dumping and separation.

Materials that can generally has various application after recycling include the following:

• Aluminium siding;• architectural antiques;• asphalt shingles;• brick/masonry;• carpet;• carpet pad;• concrete;

• concrete painted with lead-based paint;• gas pipe/metal pipe;• porcelain plumbing fixtures;• PVC pipe;• site clearance vegetative woody debris;• steel - structural or rebar;• untreated lumber and other wood;• vinyl siding; and• wallboard/drywall (gypsum).

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Lumber(wood logs)

• Can be used for used later as fire blocking, spacers in header construction, etc.

• sawdust for use in compost piles or around gardens.

Recycle lumber(wood log).

Drywall

• Drywall is the principal wall material used in the United States for interior purposes. It is made of a sheet of gypsum covered on both sides with a paper facing and a paperboard backing. Drywall can be recycled into new products.

• Drywall scraps can be placed in the interior wall cavities during new construction.

• Gunite Support: Gunite is concrete sprayed on at high pressure. Cutoff pieces of new construction drywall can be used as forms to support gunite as it is being sprayed. A swimming pool construction company uses new cutoffs for this purpose, in sizes from 4 x 2 ft to 4 x10 ft, and thickness of 1/2 to 3/8 in. The pieces are then discarded.

sheet of gypsum.

Masonry

• During construction, collect, stack and cover brick and other masonry materials to prevent soiling or loss.

• Salvage usable bricks, blocks, slate shingles, tile and other masonry materials from remodeling and construction. Store for future jobs or divert to salvage operations.

• Good quality used concrete (also known as urbanite) can also be used as brick or block for landscaping walls and foundations for small buildings.

Bricks separated.

Metals and Appliances

• During remodeling, separate metal radiators, grates, piping, aluminum siding, and old appliances for salvage or recycling.

• During construction, separate metals for recycling, including copper piping, wire and flashing; aluminum siding, flashing and guttering; iron and steel banding from bundles, nails and fasteners, galvanized flashing and roofing, and rebar;

Metals recycle.

Cardboard and Paper

• Separate cardboard waste, bundle, and store in a dry place. Recycle through Ecology Action.

• Can be used for recycled paper making and packaging goods.

Cardboard and Paper recycle.

Paints, Stains, Solvents and Sealants

• Donate unused portions to Habitat for Humanity ReStore. They accept any quantity of white latex paint and full gallons of other paints.

• Any other unused materials should be taken to a hazardous waste collection facility.

Paints, Stains, Solvents and Sealants recycle.

Miscellaneous

• Branches and trees from brush clearing can be stored separately and chipped at the city’s landfill facility, or a chipper can be used on site to create landscaping mulch.

• Old nickel cadmium batteries from portable power tools should be disposed of at a hazardous waste collection facility.

• Cabinets, light fixtures, bathtubs, sinks, mortar mix, hardware, nails, screws and plumbing fittings and supplies are all accepted by Habitat for Humanity.

Case studies:

• Fletcher Insulation: recycling glass into insulation.• CSR Gyprock™ take-back scheme for gypsum board

product.• PIPA recycling PVC pipes into new product.• Eastern Metropolitan Regional Council: wood is too

good to waste.• Recycling power poles into high-value timber

products.• Waverley Council: recycled glass in roads.• Recycling waffle pod waste.

Case study: Waverley Council: recycled glass in roads: Australia

• There is an estimated 75 000 tonnes of crushed glass fines in New South Wales.

• This material is destined for landfill unless an alternative use can be found.

• In the concrete industry, glass powder can be used alternate to natural sand. This can save them $2.25 million.

Recycling residential asphalt shingles in Wisconsin

• Benefits of shingle recycling• Recycling shingles has many benefits, especially when the

price of oil and virgin asphalt is high.• Highway engineers have investigated use of shingles that

are recycled into an additive for hot mix asphalt to build or repair roads.

• Recycling also saves landfill space and uses less energy than using virgin materials.

• Asphalt shingles contain asphalt cement "binder" and mineral aggregate, which are useful for asphalt hot mix pavement applications if proportioned well.

Recycling residential asphalt shingles in Wisconsin

Using wood waste from a construction site for erosion control and soil amendment

• Unpainted and untreated wood that is chipped or shredded can be used for erosion control, landscaping, trail surfaces and soil amendment.

• Limitations:• Placement of wood within an area designated as

a floodplain should be limited to thin layers for landscaping and trail surfaces.

• Improper use of wood chips and sawdust can damage surface and groundwater quality.

Using wood waste from a construction site for erosion control.

Concrete Recycling and Disposal

• Broken-up pieces of sidewalk or used concrete paving stones can be used to build new paths and walkways around your home and yard.

• Smaller pieces of concrete are used as gravel for new construction projects.

• Crushed recycled concrete can also be used as the dry aggregate for brand new concrete if it is free of contaminants. Also, concrete pavements can be broken in place and used as a base layer for an asphalt pavement through a process called rubblization(creating a base for new roadways)

Broken-up pieces: beneficiary use on ruptured road.

• Larger pieces of crushed concrete can be used as riprap revetments, which are "a very effective and popular method of controlling streambank erosion.

• Also for creating a base for new roadways.

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riprap revetments.

References:

• Current practices and applications in construction and demolition debris recycling: by Edward L. von Stein and George M. Savage.

• Construction Waste Recycling: Sustainable Sources: 20 years of online Green Building information.

• http://www.epa.gov/lead/pubs/nlic.htm• http://dhfs.wisconsin.gov/lead/