Salient issues and recommendations emerged out of deliberations
- It is recommended that
all the G.Os on the promotion of fly ash and blended cements
be reviewed in practical lines in order to bring out a pragmatic
action plan. For this purpose, it is further recommended that
the Committee of Engineers-in-Chief would conduct their meeting
at the earliest in order to provide necessary technical inputs
to the government with regard to the successful implementation
of the G.Os.
- It is also recommended
that all departments would update their Standard Schedule of
Rates (SSRs) with the new materials.
- It is recommended that
all the departments fix targets for themselves with regard to
replacement of conventionally used materials with fly ash brick/block
and blended cements. A committee may monitor these targets with
suitable mechanism for performance-linked recognition.
- It is recommended to
update the manuals for new materials, highlighting additional
technical virtues despite price parity.
- It is recommended that
the government sets up laboratories at each district head quarter
to facilitate studies on fly ash evaluation and advanced concrete
technology.
- It is recommended that
government laboratories evaluate fly ash blended concretes in
order to optimize the mix design. INSWAREB has offered technical
support for these studies in understanding various issues.
- It is recommended to develop
a comprehensive database on the strength gain of blended cement
concrete at various ages in order to draw the schedule for removal
of formwork.
- In view of the service
of blended cements concrete to ecology and economy of the nation,
It is recommended that Government should resort to propagate
through media the engineering virtues of fly ash blended cements
and fly ash brick/blocks.
- It is recommended that
prompt payments be made to small and tiny sector entrepreneurs,
in the lines of payment to steel and cement, for the supply
of fly ash bricks/blocks to government-sponsored housing programs,
without subjecting them to the mercy of beneficiaries or to
the delay tactics from vested interests.
- It is recommended to
extend the validity of sales tax exemption (for fly ash bricks
and blocks and machinery used for their production) by ten years
since no tangible results could be achieved by 2003, which was
the target period to achieve 100% replacement with fly ash based
brick.
EXPLANATORY NOTE FOR THE
RECOMMENDATIONS:
The Workshop has
primarily targeted to have interaction with departmental engineers
who were deprived of opportunities to practise advanced concrete
technology on one reason or the other. In view of the nature of
the subject that summoned for more floor interaction, technical
presentations were limited to a few, encouraging more and more delegate
interaction. The discussions were lively in view of practical problems
posed by the departmental engineers. It would have
been nice if the issues posed by faculty members from universities/institutions
were associated with accountability. Despite vast research facilities
and dedicated time at their disposal, these very questioners missed
to take up studies on the subject that would have provided answers
on the very issues they sought to discuss.
Government
Orders (G.Os), Manuals and Standard Schedule of Rates (SSR)
It is recommended
that all the G.Os be reviewed in practical lines in order to bring
out a pragmatic action plan. It is further recommended that the
Committee of Engineers-in-Chief would conduct their meeting at the
earliest in order to provide necessary technical inputs to the government
with regard to the successful implementation of the G.Os.
It is also
recommended that all departments would update their SSRs with the
new materials. In this context, it is sufficiently clarified that
the revision of IS:456-2000 (code of practice for concrete) is adequate
enough to facilitate the departments to switch over to blended cements
on durability criteria.
It is recommended
that all the departments fix targets for themselves with regard
to replacement of conventionally used materials with fly ash brick/block
and blended cements. A committee may monitor these targets with
suitable mechanism for performance-linked recognition.
It is recommended to update the manuals for new materials, highlighting
additional technical virtues despite price parity.
Evaluation of fly ash to understand the characteristics:
It is recommended
that the government sets up laboratories at each district head quarter
to facilitate studies on fly ash evaluation and advanced concrete
technology.
Mix Designs
for fly ash blended concretes:
PPC and FaL-G have
low bulk density in comparison to OPC. Hence there is a need to
reorient volumetric dose based on weight of cementitious material
derived in accordance to mix design.
Keeping in
view the slow rate of strength gain with fly ash more so at early
ages, mix designs need to be oriented commensurately for fly ash
based concretes.
It is recommended
that government laboratories evaluate fly ash blended concretes
in order to optimize the mix design. INSWAREB has offered technical
support for these studies in understanding various issues.
Curing
regime for fly ash based concretes:
This issue has been
discussed at length. It is clarified that, though blended cement
chemistry renders relatively lower strengths to concrete in comparison
to that of OPC, the grade strengths are normally achieved as required
for formwork removal. It is further clarified that as long as IS:456-2000
is followed the practice would be safer. However, to have a common
code of understanding, it was felt necessary to know the schedule
for removal of formwork commensurate to strength gain. ENC, Panchayat
Raj, suggested that government laboratories initiate the studies
to correlate and record relation between curing and strength for
various concrete grades based on blended cements.
It is recommended
to tabulate various results into comprehensive database so as to
make the same available for due codification.
Impact value
of fly ash concretes to use the latter in road construction:
It is globally established
that fly ash blended concrete has higher MOR and ultimate strengths
in view of sound bonding at transition zone in comparison to OPC.
This aspect may contribute for high impact values also. However,
to quantify the same in absolute terms, Chaitanya Bharathi Institute
of Technology (CBIT), Hyderabad, offered to undertake work in this
direction and develop substantial data. ACT Foundation, the division
of INSWAREB, declared Fellowship for this purpose.
Propagation
on the virtues of blended cement concrete:
The cement and concrete
companies are sufficiently publicizing about the engineering virtues
of blended cement concretes. However, in view of the service of
blended cements concrete to ecology and economy of the nation, it
is recommended that Government should resort to propagate through
media the engineering virtues of fly ash blended cements and fly
ash brick/blocks.
Payment of bills to SSI units engaged in FaL-G brick/block production:
It is recommended
that prompt payments be made to small and tiny sector entrepreneurs,
in the lines of payment to steel and cement, for the supply of fly
ash bricks/blocks to government-sponsored housing programs, without
subjecting them to the mercy of beneficiaries or to the delay tactics
from vested interests.
Extension
of Sales tax exemption:
It is recommended
to extend the validity of sales tax exemption (for fly ash bricks
and blocks and machinery used for the same) by ten years since no
tangible results could be achieved by 2003, which was the target
period to achieve 100% replacement with fly ash based brick.
Economic
zone for fly ash procurement:
It was clarified
that procurement of fly ash is feasible even in a radius of 1000
km wherever blending of fly ash at site is proposed. Similarly it
was justified that, for manufacturing brick and blocks, a logical
radius of 400 km is feasible for procurement of fly ash.
Interaction
with power plants to get fine fly ash for on-site blending with
concrete:
The power plants
may organize their fly ash collection in such a way that the fine
fly ash from 2nd to last field is collected and delivered to concrete
industry, who opt to add fly ash directly into the concrete.
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