This document discusses recycled aggregate concrete (RAC). It defines RAC as concrete produced using recycled concrete aggregates. These aggregates are produced by crushing waste concrete. The document outlines the characteristics, classification, production process, uses, benefits and conclusions regarding RAC. It finds that RAC has lower strength but can be used for applications like road bases. Using RAC provides benefits like reduced waste and cost savings compared to using natural aggregates.

1. GUIDED BY :-
HOD
SREEJITH K BABU
CIVIL ENGINEERING
MGM POLYTECHNIC COLLEGE
BY :-
GOKUL KRISHNA G
ROLL NO :- 09
S 5 CIVIL ENGINEERING
MGM POLYTECHNIC COLLEGE 01

2. ➢ What is Recycled Aggregate?
➢ Characteristics of RAC
➢ Classification
➢ Processing of RAC
➢ Production of RAC
➢ Use of RAC
➢ Application
➢ Benefits
➢ Conclusion
➢ REFERENCE
CONTENT
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3. ➢ To achieve sustainable issue in construction area, researchers and companies
focus on using waste concrete as a new construction material. It is called
recycled aggregate which can be produced by concrete Crusher.
➢ The aggregates are categorized by size as coarse and fine aggregate.
➢ The characteristic of recycled aggregates could be different by its parent
concrete because the parent concrete was designed for its purposes such as
permeable, durable and high strength concrete
INTRODUCTION
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4. ➢ Its a lower density, elastic modulus, strength and a higher water
absorption capacity.
➢ recycled aggregate has a proportional mortar which attached to
aggregate, it gives a higher porosity and a lower strength to RAC
than the normal concrete.
➢ In addition, since recycled aggregates require a more amount of
water than natural aggregate, shrinkage issue could be a problematic
to be use RAC in parctially.
WHAT IS RECYCLED AGGREGATE
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5. ➢ Recycle aggregate concrete has a Crushed sound and clean waste concrete
of at least 95% by weight of concrete with typical total contamination lower
than 1 %of the bulk mass
➢ Class IARCA is a well graded RAC with no more than 05% brick content
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6. CLASSIFICATION
Material composition is the basis for classification of
recycled concrete aggregate in two main types
1) Crushed concrete
2) Mixed material
Each of these types is divided in a class for bound and a
class for unbound use
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7. 1. Crushed concrete: This materials generally resulted in increased water demand and
decreased workability.
2. Mixed concrete: Mixed concrete remain plastic for a short time. This properties are
important because they affect the quality and in place cost of the hardened concrete
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8. DEPARTMENT OF CIVIL ENGINEERING MGM PTC
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9. ➢ crushing
➢ pre-sizing
➢ sorting
➢ screening
➢ contaminant elimination
PROCESS OF RAC
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10. Fig:Process of recycle aggregate concrete
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11. ➢ Crushing and screening systems start with primary jaws, coes and/or large
impactor taking rubble from 30 inches to 4 feet.
➢ A secondary cone or impactor may or may not need to be run, and then
primary and secondary screens may or may not be used, depending upon the
project, the equipment used and the final product desired
➢ A scalping screen will remove dirt and foreign particles. Afine harp deck
screen will remove fine material from coarse aggregate
➢ Further cleaning is necessary to ensure the recycled concrete product is free
of dirt, clay. wood, plastic and organic materials.
➢ This is done by water floatation, hand picking, air separators,
andelectromagnetic separator.
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12. DEPARTMENT OF CIVIL ENGINEERING MGM PTC
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13. ➢ In paved roads as aggregate bole aggregate subbase, and shoulders.
➢ In gravel roads as surfacing
➢ As bane for building foundations
➢ As fill for utility trenches
➢ At this time, the primary market is aggregate base and subbase in road projects
➢ Local Government: Local governments can help promote markets for recycled
aggregate because they are large purchasers of aggregate and other road
construction products
USES
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14. DEPARTMENT OF CIVIL ENGINEERING MGM PTC
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15. CLASS-H
CLASS-M
CLASS-1
No limitation are put on the type
segment for concrete & structures with a nominal strength
of45 mpa or less.
Member not subjected to drying or
freezing - and – thawing action, such as piles under ground
beam and concrete fill in steel tubes.
Backfill concrete, building concrete, and leveling concrete
APPLICATION OF RECYCLED AGGREGATE
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16. ➢ There are a variety of benefits in recycling concrete rather than dumping it or
burying it in a landfill.
➢ Keeping concrete debris out of landfills saves landfill space.
➢ Using recycled material as gravel reduces the need for gravel mining Using
recycled concrete as the base material for roadways reduces the pollution
involved in trucking material.
BENEFITS
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17. ➢ Reduces the amount of virgin aggregates to be Crated, hence less evacuation of
natural resources
➢ While being crushed into smaller particles a large amount of carbon dioxide is
absorbed. This duces the amount of CO, is the atmosphere
➢ Cost saving - few research studies have shown a significant reduction in construction
costs if RAC is used Conserves landfill spare, reduces the need for new landfills and
hence Creates more employment opportunities is recycling industry.
ADVANTAGES OF RAC
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18. ➢ Downgrading of quality of concrete
➢ Increase in water absorption capacity ranging from 3% to 994
➢ Decrease in compressive strength of concrete (10 - 30%)
➢ Reduces workability of concrete.
➢ Lack of specifications and guidelines.
➢ Less durability of RM. however few papers have shown an improvement
in the durability by mining it with special materials like fly ash
DISADVANTAGES OF RAC
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19. ➢ Initial moisture states of RCA is one of the most important variables that
impact strength and shrinkage.
➢ When oven-dried RCAis used, strength is used to be greatly reduced but free
shrinkage as measured in this study was low.
➢ The creep to free shrinkage ratio for RAC was similar to that of normal
concrete at 7 days under restrained conditions.
➢ When greater volume of recycled fine aggregates and fly ash was used, free
shrinkage of the specimens was reduced.
CONCLUSION
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20. ➢ The use of recycled aggregate has been found to be better than that of
virgin aggregates for certain applications. For example, the physical
properties of recycled aggregates make them ideally suited for road base
and sub-base. This is because of their physical properties which means
less cement is required making them suited for sub-base use. This is in
addition to the cost benefits accrued by developers in the process.
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21. RECYCLED AGGREGATE CONCRETE
➢ KK Sagoe - Crentsil, T Brown, AH Taylor Cement and concrete research, 2001 -
Elsevier
REFERENCE
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➢ By the reference of slideshare website.
➢ M. Heemlal, P. Rathish Kumar, Y.V. Rao and V. Tulasi Shiva Kalyan, A study on
the utilization of recycled concrete aggregates (RCA) in bituminous concrete.
➢ Katrina McNeil and Thomas H-K Kang, Recycled Concrete Aggregates: A Review,
International Journal of Concrete Structures and Materials Vol 7. No.1. pp 61-69,
March 2013
DEPARTMENT OF CIVIL ENGINEERING MGM PTC

22. THANK YOU
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