INTRODUCTION
With the increase in demand for construction along with development . in infrastructure, the demand of construction material is also increasing. Among this construction material, one " the important construction materials is River Sand and stone aggregates. Construction and demolition waste is generated whenever any construction/demolition- activity lakes place, such as, building roads, bridges; over, subway, re modeling etc. It consists mostly of inert and non-biodegradable material such as concrete, plaster, metal, wood, plastics etc. A part' of this waste comes to the municipal stream.
CRUSHED CONCRETE DEBRIS
It is estimated that the construction industry in India generates about 10-12 million tons, of waste annually. Projections for building material requirement of the housing sector indicate a shortage of aggregates to the extent of about 55.000 million. An additional 750 million aggregates would be required for achieving the targets of the road sector. Recycling of aggregate material from construction and demolition waste may reduce the demand-supply gap in both these sectors.
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. The end-use of the aggregate recovered from concrete waste depends on its cleanness and soundness, which are controlled by the .source of Origin of the rubble and the processing technology. Aggregate recovered from surplus fresh concrete in pre casting yards and ready-mixed concrete plants is generally clean and similar in properties to the virgin aggregate.
Huge machines are required to carry out the process of concrete crushing. There are many of the crushing plants installed to any out the concrete crushing. Other than these concrete crushing factories Other than these concrete crushing factories there are also, moveable mobile concrete crushing machines available.
CONCRETE DEBRIS IN INDIA
Construction and demolition waste is generated whenever any construction/demolition activity takes place, such as. building roads, bridges; fly over, subway,' re modeling etc. It consists' mostly of inert and ,non-biodegradable material such as concrete, plaster, metal, wood,
.-plastics etc. A part of this waste comes to the
. municipal stream.
is then crushed. The concrete crushing process includes crushing of concrete into small pieces, it is not as easy to do concrete crushing.
USES OF CRUSED CONCRETE
Concrete and masonry waste can be recycled by sorting, crushing and sieving into recycled aggregate. This recycled aggregate can be used to make concrete for road construction and building material.
EXPERIMENTAL INVESTIGATIONS
ORDINARY PORTLAND CEMENT
In the present investigations OPC 53 grade was used and the cement has been tested to obtain following properties.
COARSE AND FINE AGGREGATE
Coarec aggregate with the size 20mm was used. The (RFA) recycled line aggregate was obtained from the waste concrete debris by crushing the debris .The aggregate size 4.75mm to 120 microns were taken as line aggregate. The physical properties of river sand and rec\eled aggregate used are given I table 3

CONCRETE CRUSHING
Concrete is basically the solution of cement, sand and some other building materials. When some buildings or houses are demolished, the leftovers and useless concrete and construction materials can be pul into use. This leftover concrete
CASTING, CURING AND TESTING
The mix design chosen for the present investigation is 1:1.58:3.18 with water cement ratio 0.65.The percentage replacement of RFA with fine aggregate was done for 0%,25%.50%:75%,100%.
For each percentage of replacement nine cubes of 150mm in size and three flexure beams of size IOOmmxlOOmm.N500mm were cast using steel moulds and compacted using a tamping rod. The cast specimens are were kept in ambient temperature for 24 hours. Alter 24 hours they were demoulded and placed in water for curing. Six cubes were used to determine the compressive strength and the other three cubes were use to evaluate the density and water absorption at 14 days. Flexure beams was used to find out the flexure strength of concrete at 14 days by three points loading using a universal testing machine of capacity IOO0KN.
TEST PROCEDURES
The workability tests were conducted for the recycled concrete and the results were given in
the table 4.

FLEXURALSTRENCTHTEST:
Concrete as we know is relatively strong in compression and weak in tension. In reinforced concrete members, little dependence is placed on the tensile strength of concrete since steel reinforcing bars are provided to resist all tensile forces.
COMPRESSIS'E STRENGTH TEST
To determine the compressive strength of the concrete cube moulds of size 150X150X150mm were used. The line aggregate sand was replaced with RFA (Recycled concrete aggregate). The cubes were casted and cured for 7 days and 28 days. The table shows the compressive strength results.
WET AND DRY DENSITY OF CONCRETE
For density studies cubes of size 150x 150x 150mm were casted. Weight of the mould is measured, before and after pouring the concrete into the mould to get the wet weight of the concrete. The weight of the cube is measured after demoulding has been done. Wet and dry density is measured using the formulae.

FLEXURALSTRENCTHTEST:
Concrete as we know is relatively strong in compression and weak in tension. In reinforced concrete members, little dependence is placed on the tensile strength of concrete since steel reinforcing bars are provided to resist all tensile forces.

Density = Mass/Volume

WATER ABSORPTION TEST
> Water absorption lest ol' each specimen was carried out in accordance with BS: 1881 pan 5.
> The specimen was oven dried for 72 hours at 115 degree centigrade.
> The temperature is high enough lor the evaporation of incrtial moisture from i

GENERAL
Research on the usage of waste
construction materials is very important as the
quantity of waste materials is gradually increasing
as a result of increase in population and increase in
urban development.
The reasons that many investigations and analysis had been made on recycled aggregate arc because recycled aggregate is easy to obtain and the cost is cheaper than virgin aggregate. Virgin aggregate need to mine but recycled aggregate can ignore this process.
Furthermore, with the cheaper price of recycled aggregates compared to natural aggregates, the builders can carry out the construction task with lesser material costs. From the present experimental investigation it was found that the recycled aggregates will influence much in hardened properties of concrete.
CONCLUSIONS
While comparing with conventional concrete there is an overall rise of 25% in strength .For 25% replacement of RFA, the compressive strength obtained was 39.25Mpa.Similarly, the compressive strength for 50%. 75%, 100% replacement of RFA are 39.9IMpa, 42.27Mpa and 42.33Mpa respeclively. Therefore, as the percentage of replacement of w -sand increases, the compressive strength of the concrete also increases. Apart from this more studies are required to understand the long term durability characteristics of concrete made using recycled aggregates .Overall, it is recognised that the

recycling and reuse of demolition waste may not always be economic or practical and in some cases may be impacted by the external issues such as regulatory and planning controls. However, if the construction industry as a whole question need for aggregates and review alternatives on a case by case basis then it is possible that the result may give both economic and environmental benefits.
REFERENCES
[I] Dhir, R.K., Henderson, N.A. AND Umbachiya, M.C (edit). Proceedings of" the International Conference on the Use of Recycled Concrete Aggregates. Thomas Telford. UK. 1998.
[2] CSIR Building and Construction Technology, Reusing construction and demolition waste, Technobrief, June 2000.
[3] Rao Akash. Kumar N. Jha and Sudhir Misra (2007).Use of aggregates from recycled
construction and demolition waste in concrete. Resources.Conservation and Recycling, Volume 50, Issue 1,71-81.
[4] Poon Chi-Sun and Dixon Chan (2007). The use of recycled aggregate in concrete in Hong Kong.Resources, Conservation and Recycling 50: 293-305.
[5] Aggregates Advisory Service-UK, Digest no. 016, Construction and demolition waste Management practices and their economic impacts-study for DGXI- European Commission, May 1999.
[6] Sharma, P.C., Nagraj, N.(I999), "Recycled Aggregate Concrete and Its Importance in Indian Conditions'- All India Seminar on Indian Cement Industries : Challenges and Prospects of Cement" Chandrapur (Maharashtra)
Claim
1.For replacement ratios of crushed concrete debris as fine aggregate in concrete 0.25,0.75,1