Qasim Khan | NWFP University of Engineering & Technology (original) (raw)

Papers by Qasim Khan

Recycled aggregates are comprised of crushed, graded inorganic particles processed from the mater... more Recycled aggregates are comprised of crushed, graded inorganic particles processed from the materials
that have been used in the constructions and demolition debris. The aim for this research was to determine
the performance of recycled aggregate in the structural concrete giving a better understanding on the
properties of concrete with recycled aggregates, as an alternative material to coarse aggregate in structural
concrete. The investigation was carried out using workability test, compressive test and indirect tensile
Test.

Test Samples were prepared from the virgin aggregate and workability test, compressive test and indirect
tensile test were performed. After testing, samples were recycled to obtain recycled aggregate, a replica of
demolished concrete structure in real life. The recycled aggregate samples were prepared in two batches.
In the first batch the water cement ratio was kept same (0.55) as that in case of virgin concrete. In the
second stage the water cement ratio was increased up to 0.60 to check the variation of concretes specimen
in strength and workability.

It was found that at the same water / cement ratios, the workability of virgin concrete is higher than that
of recycled concrete. Similarly at water / cement ratio of 0.55, the compressive strength and Tensile
strength of recycled concrete is appreciably lower than that of virgin concrete. However, at higher w/c
ratio of 0.60, the compressive and tensile strength of recycled concrete is very close to that of virgin
concrete. Unlike virgin concrete in which compressive strength decreases as water / cement ratio
increases, in recycled concrete the contrary is the case, i.e. strength increases with increase in water /
cement ratios.

Recycled aggregated can be used with confidence in construction works with increased water cement
ratio. The environmental issue can be effectively addressed by avoiding the dumping of the demolished
materials associated with the elimination costs pertaining to the disposing operations.

Keywords Virgin Aggregate, Recycled Aggregate, Workability

Recycled aggregates are comprised of crushed, graded inorganic particles processed from the mater... more Recycled aggregates are comprised of crushed, graded inorganic particles processed from the materials
that have been used in the constructions and demolition debris. The aim for this research was to determine
the performance of recycled aggregate in the structural concrete giving a better understanding on the
properties of concrete with recycled aggregates, as an alternative material to coarse aggregate in structural
concrete. The investigation was carried out using workability test, compressive test and indirect tensile
Test.

Test Samples were prepared from the virgin aggregate and workability test, compressive test and indirect
tensile test were performed. After testing, samples were recycled to obtain recycled aggregate, a replica of
demolished concrete structure in real life. The recycled aggregate samples were prepared in two batches.
In the first batch the water cement ratio was kept same (0.55) as that in case of virgin concrete. In the
second stage the water cement ratio was increased up to 0.60 to check the variation of concretes specimen
in strength and workability.

It was found that at the same water / cement ratios, the workability of virgin concrete is higher than that
of recycled concrete. Similarly at water / cement ratio of 0.55, the compressive strength and Tensile
strength of recycled concrete is appreciably lower than that of virgin concrete. However, at higher w/c
ratio of 0.60, the compressive and tensile strength of recycled concrete is very close to that of virgin
concrete. Unlike virgin concrete in which compressive strength decreases as water / cement ratio
increases, in recycled concrete the contrary is the case, i.e. strength increases with increase in water /
cement ratios.

Recycled aggregated can be used with confidence in construction works with increased water cement
ratio. The environmental issue can be effectively addressed by avoiding the dumping of the demolished
materials associated with the elimination costs pertaining to the disposing operations.

Keywords Virgin Aggregate, Recycled Aggregate, Workability