ABSTRACT

Growing population and shifting from rural to urban areas have posed lest of
problem. One among them is the accommodation particularly in areas Where space.
problem is dominant's has construction of new building with more accommodation.
space in place of old structures is necessary. This produce huge quantum of concrete
waste this waste generally goes to landfill which need good resources to deal with the
problem. An automotive of it is to make use of concrete waste in new construction.
Therefore research to evaluate such possibilities started and is active these days.
This research were conducted experimental evaluation of strength deflection and
cracking behavior of reinforced of concrete slabs made with recycled aggregate from
demolished concrete waste as partial replacement of natural coarse aggregate. The
replacement is done in 50%, 60%, 70% and 80% proportion to compare the results
one batch of slab is cost with 100% natural aggregate.
Demolished concrete is collected from various location of Nawabshah. Bulky pieces
of concrete are hammered down the maximum size of I " inch followed by evaluation
of basic properties of aggregate. In addition to slabs, four cylinders from each batch
of concrete are also prepared to evaluate compressive strength. For all batches of
concrete 1:2:4 is used with 0.45-0.55 water cement ratio. Cylinders are tested for
compressive strength and maximum reduction in strength is obtained as 12.6% for
50% replacement of natural coarse aggregate with recycled concrete aggregate. All
slabs are tested by applying central point load. Average reduction in load carrying
capacity is recorded as 7.1% for 50% replacement of natural aggregates. Maximum
deflection recorded is 4.4mm which is with in allowable limits of ACI 318. Cracking
behavior of all slabs is also observed and it is found that cracking pattern remained
almost same for all models how ever reduction in cracking load with increased
percentages of recycled aggregate is recorded. Based on result it is concluded that
coarse aggregates from demolished concrete can effectively be used in reinforced.