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TECHNICAL PAPER COLLECTOR’S EDITION

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(iii) waste construction material formed due to housing , The available literature indicates that
natural disasters like earthquake, cyclone only limited studies have been made on the use of
and flood, and brick masonry demolition waste as aggregate for
making concrete. Hence, a systematic investigation
(iv) war-inflicted damages. on physical and mechanical properties of
aggregate obtained from demolished concrete
Most of the waste materials produced by and masonry with two types of bricks, and their
demolishing structures is disposed by dumping relative performance in making recycled aggregate
them as land fill or for reclaiming land. But with concrete has been carried out. The main aim of this
the demand for land increasing day by day, work is to assist field engineers with experimental
the locations, capacity and width of the land data on different types of recycled aggregate
that can receive waste materials are becoming concrete, which will enhance their confidence
limited. Add to it the cost of transportation, which and thereby facilitate wider adoption of recycled
makes disposal a major problem. Hence, reuse aggregate concrete with proper understanding of
of demolition waste appears to be an effective its strength and behaviour.
solution and the most appropriate and large-scale
use would be to use it as aggregates to produce
concrete for new construction. After the second EXPERIMENTAL PROGRAMME
world war, a number of European countries Tests on aggregate
(notably Germany, England, and the Netherlands) To start with, it is essential for any study to
and Japan have made attempts to study and reuse establish the basic characteristics of the materials
demolition materials in the construction of civil proposed to be used. As a first step, in order to
1
engineering works . have a basis for comparison, the properties of
fresh granite aggregate were determined. Three
An extensive review of literature on the recycled types of recycled coarse aggregates were prepared
aggregate concrete has been presented by from old concrete cubes of unknown strength
2
Hansen , The salient characteristics of the recycled (original concrete), masonry with wire-cut bricks
aggregate and concrete as presented by various and masonry with table moulded (country) bricks
authors 3-10 is compiled in Table 1. In general, it by crushing, first using a 1000 kN compression
has been concluded that the recycled concrete testing machine, followed by use of hammer. Then
aggregate possess relatively lower density the crushed products were screened through 25
and higher water absorption characteristics as mm sieve and the aggregates retained on IS sieve
compared to those of fresh granite aggregate. no. 480 were used for making recycled aggregate
The percentage reduction in compressive strength concrete. The physical properties (viz., particle size
of recycled aggregate concrete as compared to distribution, specific gravity,water absorption, bulk
original concrete is reported to range between 5 density, voids, elongation index and flakiness index)
to 32 percent. Chitharanjan has investigated the and mechanical properties (crushing and impact
use of brick rubble (brick kiln waste) in making value) of these aggregates were determined as per
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building blocks considering two mix proportions, IS:2386 and compared with those of fresh granite
that is, 1:5:10 and 1:6:12 for its use in low-cost mass aggregate.

76 The Indian Concrete Journal | November 2018