USE OF CONSTRUCTION AND DEMOLITION WASTE BY BABITHA & YASHODHA SIETK (puttur) Email: email@example.com
Introduction:Demolition sites & restoration schemes are large amounts of solid waste.Recycling of concrete & other building materials is difficult &uneconomical.It is possible to reuse most of the building materials & components.As the volume of demolition waste is huge allowing the waste to becrushed, processed, & reused as aggregate in building works.The recycling of construction materials like concrete, timber , glass, &steel is primarily an attempt to reduce the cost of production of newmaterials & construction & also reduce the consumption of naturalresources.
WHAT IS C & D WASTE?Renovation Demolition New Construction 40% 50% 10%
WHAT DOES C & D WASTECONSISTS OF?ConcreteBrickTimberSanitary wareGlassSteelplastics
CONCRETE:o Concrete is one of the most important construction material.o Approximately one ton of concrete is used per capita per year throughout the world.o Recycling of concrete reduces• Cost of aggregates• Disposal costs• Environmental damage• Consumption of natural resources &• Valuable landfill spaceo Recycled coarse aggregates may be more durable than virgin material.o It can also be used in residential construction
BRICK:o Broken & discarded brick can be used asconstruction infill or as aggregate for non-structural concrete.o Brick that are part of demolish rubble can becrushed and used in the same way.o Brick masonry rubble contains mortar upto20% by volume.o Crushed brick & roofing tiles are the bulk ofdemolition waste which were earlier being dumpedin landfills, but now they can be recycled into mortarplaster & building blocks.
TIMBER:o It is mostly crushed into chip & used as fuel.o It can also be utilized to manufacture wood-chipconcrete by injecting cement grout into voids ofcompacted wood-chips in moulds.o Wood-chip concrete can be used as building material.o This chip can be sawn & nailed as well.o In Japan alone about 12 million cubic metersof used timber from demolished houses are used.
SANITARY WARE:o Sanitary ware includes tiles also.o There can be reused as it is, if they are not damaged.o If sanitary ware are chipped (or) cracked(or)otherwise damaged are advised to crush anduse them as construction infill (or) as filler in concrete.o Pozzolanic value of such crushed & powdered sanitary ware, is a desirable property in concrete mixes.
GLASS:o One ton of recycled waste glass corresponds to savings in energy equivalent to 125lit of fuel oil & 1.2tons of raw materials.o Recycling of glass reduces non-biodegradable glass out of landfills.o Glass can be used as substitute for Quartz &Feldspar in the manufacturing of high strengthprocelain sanitary ware.o It can also be used to make mineral wool- an insulation product & in granular form as part of the aggregate in concrete mixes.o In USA an experiment was conducted on metal free-glass constituents separated from municipal incinerator residue. This glass was used to produce brick, glass-wool thermal insulation & as a major component of a light weight aggregate used in structural concrete.
STEEL:o Steel is most commonly used metal in the world.o Steel reinforcement from demolished concrete is usually separated from the rubble on site &sold scrap to recycling plants.o The world produces over 783 million tons ofraw steel. It currently recycles over 320 million tons of iron & steel every year.o Scrap metal can yield energy savings of upto 76% .o In Europe steel is most recycled .
PLASTIC:o There is an over abundance of waste plastic.o It is very difficult to dispose plastics.o Waste plastics can be shredded & used asfiller in other materials such as concrete& also in construction of roadso House hold plastic waste can also be recycledto obtain artificial light weight aggregatesfor mortar.o Plastics reduces the possibilities of cracking.
Conclusion: It has been established that materials & components from demolished buildings are being reused for new construction works as well as renovation projects, especially by low- income communities in developing countries. In developing countries most of the demolition rubble is dumped, the developed world has now started to recycle it into aggregate for non- structural concrete. It is hoped that recycling waste materials for use in the building will cut down costs of producing new raw materials thereby reducing consumption of natural resources like energy & reduces usage of landfills.
The iimportant iinitiatives sited are::1. Promoting separation of C&D waste at source2. Promoting recycling3. Ban on llandffilling of C&D waste4. Developing market for recycled products5. Production of concrete bricks and paving blocks6. Guidelines for using C&D waste7. Developing designs which ffacilitate ‘deconstruction’’iinstead of outright demolition
REFERENCES:o Abert, J.G., Resource Recovery Guide, New York: Van Nostrand Reinhold Co., 1983.o Akman, M.S., A. Güner, and I.H. Aksoy, "Historical and Technical Specifications of the Khorasano Mortar" (Horasan Harci ve Betonunun Tarihi ve Teknik Özellikleri), 2nd Internationalo Congress on the History of Science and Technology in Turko-Islamic Era, ITÜ, Istanbul, 1986.o Hendriks, Ch.F., The Use of Concrete and Masonry Waste as Aggregates for Concrete Production inthe Netherlands, Environmental Technology: Proceedings of the 2nd. European Conference in