Construction Middle East: Arabian Civil Engineers by GineersNow GineersNow Engineering Magazine Issue No. 014, Sau | Page 49

Wet concrete recycling: Builders often order
a little more ready mixed concrete than they
actually need, so it is common for concrete trucks
to have wet concrete remaining in their drum after a
delivery. This unused concrete can be returned to
the ready mixed plant and either (1) used to pour
precast concrete products (e.g., highway barriers,
retaining wall blocks, riprap), (2) used to pave the
ready mixed plant’s yard, (3) washed into a
reclaimer, or (4) dumped on an impervious surface
and allowed to harden, so it can be crushed and
recycled as aggregate. Unused wet concrete
should not be dumped on bare ground to harden at
construction sites because this can contribute to
ground water and surface water contamination.
Schwing Stetter recycling plant RA 12 helps in
conserving the environment by not contaminating
the ground water through recycling of slurry water
and reusing it in making concrete.
Schwing Stetter’s RA 12 can recycle the concrete at
a washing capacity for normal concrete at 12m3
per hour. The major benefits to RA 12 are easy
operation, fully automatic, no wastage of
aggregates or raw materials, short vehicle
downtimes during cleaning, no disposal costs,
exceptionally resistant to wear, variable installation
possibilities and low operating costs.
Operation of SCHWING Stetter’s RA 12 is based on
reverse flow principle. This provides quick intake of
concrete. It separates aggregates in various sizes
ranging from 63 mm to 0.2 mm. Vibrators are
available for free concrete flow and aggregate flow.
Drum rollers are provided with nylon ring for
increased life, maintenance door provided for easy
access to wash drum, drive protection cover
provided for safety.
Typical system for recycling wash water/ aggregate
recovery is that the surplus concrete is fed into the
washing drum with the help of vibrators in the
hopper. Depending on the system, upto two trucks
can be unloaded simultaneously. The boom pump
delivers water to Transit mixer for washing. Transit
Mixer washout concrete discharges into the
charging hopper and flows into the drum. The Drum
rotates to separate the aggregate and slurry water
by reverse flow method. The slurry water gets
collected into the slurry tank. The aggregates gets
collected through vibrating sieve. The agitator stir
the slurry tank in regular interval to avoid
deposition. The rinsing pump delivers water to
drum through vibrating sieve and charging hopper.
Batching pump delivers slurry water to batching
plant for concrete production.
Our happy customers are quite a many: Leighton,
Larsen and Toubro at their Dhirubhai Ambani
International Convention centre were able to reuse
the remaining concrete from 4 lakhs m3 from the
construction site. For every 50 numbers of transit
mixers washed per day through RA 12, a total of 10
lakhs can be saved yearly.
Schwing Stetter are the best in the next generation
- recycling plant. RA 12 offers easy to use, low
noise equipment wherein it separates aggregates
and slurry from the concrete to be reused. The
major benefits of concrete recycling are keeping
concrete debris out of landfills saves landfill space,
recycled gravel reduces the need for gravel mining
and using the recycled concrete as the base
material for roadways reduces the pollution
involved in construction, satisfying legal authorities
guidelines of not allowing waste water containing
cement slurry should be allowed to be flushed into
municipal drains, minimum payback period of
capital investments made on RA 12 system. We
recently launched recycling plant RA20 at Bauma
Conexpo India 2016 to be held at Huda grounds in
Gurgaon.
Construction Leaders • April 2017
47