Tyre Asia April/May 2018 47
shredded tyre rubber is ideal.
“This size was chosen to mimic the
aggregate size used for mixture in
concrete.”
He says in terms of economy,
his research has indicated cost-
effectiveness in using waste tyre
rubber in pavement building and
repair. “Well, to be mindful, a
computational cost-effective study
requires further research into
practical implementation onsite.
It should be like an apple to apple
comparison between existing
asphalt pavement vs. recycled waste
tyre concrete pavement.”
Cost effective
Dr Krishnamoorthy suggests that
using recycled material is definitely
cost effective, and in addition,
it paves the way for a greener
and environmentally friendly
construction. Currently there is no
immediate data for a comparison.
However, he said that future
collaboration with industry will
help develop more insight into the
percentage of savings that can be
achieved.
Referring to his work on ‘flexible
pavement’ he explained that
there are two types of pavement
construction that engineers take
into consideration while executing
road projects. One is called flexible
pavement and the other rigid
pavement.Flexible pavement is commonly
used in Malaysian road construction.
However, the ‘infamous’ rigid
pavement has also been extensively
used in the North-South
Expressway. Flexible pavement
is usually asphalt. It is laid with
no reinforcement. It is normallydesigned based on load distributing
characteristics in the component
layers which include sub-grade and
layers up to the surface.
In the case of rigid pavement, there
is application of reinforced concrete
slabs. The load is distributed inthe extensive area of sub-grade
soil. Concrete material consists of
Portland cement, clean river sand,
water and coarse aggregate.Regarding his recommendation for
optimum result, he suggests 10%- 30% of shredded tyre rubber for
laying pavements.
The recommended percentage of
10% - 30% shredded tyre shows
good agreement with existing
pavement strength, he said
adding that he is still sceptical to
include pieces of shredded tyre
rubber that contain steel cord.
This could compromise the safety
of the finished recycled concrete
pavement.“Protruding steel cords are
dangerous for end-users and for the
rubber wheels when they come in
contact. However, a textile mesh
steel reinforced cord can be placed
to overcome the issue,” he feels.Dr Krishnamoorthy said his research
is aimed at upgrading the standard
concrete material that come from
industrial waste. Adding shredded
tyre rubber and ground plastic
bottles in place of coarse aggregates
in place of clean river sand will also
help preserve water bodies.R
esearch has
revealed that 6 mm
coarse shredded tyre
rubber is ideal for the
pavement. This size was
chosen to mimic the
aggregate size used for
mixture in concreteMalaysia’s North-South Highway