Now a days as the construction is increasing the demolition waste from the buildings is also increasing. We have to increase the usage of waste materials and to help for the future generation. Construction activities generate millions of tonnes of Construction and Demolition (C&D) waste materials each year. These materials contain a lot of reusable materials. If not properly managed, they will become wastes, a burden to the society, which will be extremely expensive to handle and will occupy precious landfill space. Now even for small projects it has been made mandatory to use Ready mix concrete or compulsory use of Batching plant. However, except for large projects and some industrial projects, Demolition of structures is not yet mechanised. This waste is also affects the air, noise pollution in the form of releasing dust and noise respectively. Recycling can turn the waste materials into usable products, which can help conserve our natural resources for our next generations and for the sustainable development of the society. In the recent years, C&D waste management issues have attracted the attention from researches around the world. The ultimate aim is to create the awareness among the Civil Engineers is to do the research on this topic and to reuse these materials. Main points of this PPT: • An overview of the concept on Waste management. • Brief description on “Recycled Concrete Aggregates”. • Waste reduction and Reuse. • Demolition techniques. • Use of proper Waste Management plan.

1. CONSTRUCTION
&
DEMOLITION WASTE RECYCLING
(CDWR)
By
V. ANAND
B Tech 3rd year
Department of Civil Engineering
Gokaraju Rangaraju Institute of Engineering and Technology,
Hyderabad.
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2. Introduction
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3. Constituents of C&D waste:
•Woody and plant materials
•Concrete
•Gravel, aggregate, stone and rock
•Masonry and rubble
•Metals (ferrous and non-ferrous)
•Wood
•Plastic
•Glass
•Doors and windows
•Asphaltic roofing
•Gypsum board
•Carpet and pad
•Cardboard and paper
•Plumbing fixtures
•Lighting fixtures
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4. Recycled Concrete Aggregates
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5. Definition
Aggregate resulting from the processing of inorganic material previously use in construction and principally
comprising crushed concrete washed and graded for use as an aggregate in the Production of further concrete.
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6. S.no Material Water
absorption
Specific gravity
1 Natural sand 0.21 2.6
2 Recycled aggregate 6.2 2.41
Properties of fine aggregate6

7. • many types of general bulk fills
• bank protection
• base or fill for drainage structures
• road construction
• noise barriers and embankments
Applications7

8. The crushing characteristics of hardened concrete are similar to those of natural rock and are not significantly
affected by the grade or quality of the original concrete. Recycled concrete aggregates produced from all but the
poorest quality original concrete can be expected to pass the same tests required of conventional aggregates.
Recycled concrete aggregates contain not only the original aggregates, but also hydrated cement paste. This paste
reduces the specific gravity and increases the porosity compared to similar virgin aggregates. Higher porosity of
RCA leads to a higher absorption.
Recycled Aggregate Characteristics
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9. Decrease in modulus of elasticity , tensile strength and it no significant effect on compressive strength.
It is recommended that RCA be batched in a pre wetted and close to a saturated surface dry condition,
like lightweight aggregates. To achieve the same workability, slump, and water-cement ratio as in conventional
concrete, the paste content or amount of water reducer generally have to be increased.
Concrete with RCA can be transported, placed, and compacted in the same manner as conventional concrete.
Special care is necessary when using fine RCA. Only up to 10 to 20 percent fine RCA is beneficial. The
aggregate should be tested at several substitution rate to determine the optimal rate.
Often recycled aggregate is combined with virgin aggregate when used in new concrete.
Mix design9

10. An example of a mix design using recycled aggregates in a pavement application is
shown following table.
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11. Sustainability
Recycling concrete provides sustainability several different ways. The simple act of recycling the concrete
reduces the amount of material that must be landfilled. The concrete itself becomes aggregate and any embedded
metals can be removed and recycled as well. As space for landfills becomes premium, this not only helps reduce
the need for landfills, but also reduces the economic impact of the project. Moreover, using recycled concrete
aggregates reduces the need for virgin aggregates. This in turn reduces the environmental impact of the
aggregate extraction process. By removing both the waste disposal and new material production needs,
transportation requirements for the project are significantly reduced.
In addition to the resource management aspect, recycled concrete aggregates absorb a large amount of
carbon dioxide from the surrounding environment. The natural process of carbonation occurs in all concrete
from the surface inward. In the process of crushing concrete to create recycled concrete aggregates, areas of the
concrete that have not carbonated are exposed to atmospheric carbon dioxide.
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12. Waste Management
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13. The main reasons for increase of volume of demolition concrete / masonry
waste are as follows:-
1) Many old buildings, concrete pavements, bridges and other structures have overcome their age
and limit of use due to structural deterioration beyond repairs and need to be demolished.
2) The structures, even adequate to use are under demolition because they are not serving the
needs in present scenario.
3) New construction for better economic growth.
4) Structures are turned into debris resulting from natural disasters like earthquake, cyclone and floods etc.
5) Creation of building waste resulting from manmade disaster/war.
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14. Waste reduction
&
Reuse
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15. Eliminating Waste
Some waste generated in the process of construction can be eliminated. For example, durable
modular metal form systems for use in concrete construction may be selected on the basis of
being readily demountable and reusable on other projects, thus eliminating wood waste
associated with formwork fabricated of plywood and dimensional lumber. Elimination of waste
can be beneficial to reduce impacts on human health and the environment.
Minimizing Waste
Some building-related waste can be minimized. For example, construction products can be
selected on the basis of its being designed and manufactured to be shipped with minimal
packaging. Also consider that selection and use of recyclable materials and products offers
potential to minimize waste.
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16. Demolition Techniques
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17. • Demolition by hand
• Demolition with the ball
• Demolition by pusher arm
• Demolition by deliberate collapse
• Demolition by wire rope pulling
• Demolition by explosion or implosion
• Demolition using grapples and shears
• High-reach (or Long-reach) demolition excavators
• Underwater demolition
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18. Thank you..
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