Civil Engineering Reference
In-Depth Information
another important issue that needs to be better comprehended for the
improvement of binder use efficiency is the robustness of the concrete mix.
Low binder content implies that small variation on water content will have
larger impact on water/cement ratio affecting the porosity and mechanical
strength. Also, this concretes demands efficient dispersants and the robustness
of the system cement-dispersants must be improved (nkinamubanzi and
Aïtcin 2004).
The effect of binder content reduction on mechanical behavior,
including fracture, dimensional stability and creep behavior also need to be
investigated.
2.4 Conclusion and future trends
Current strategies for decreasing Co
2
emissions in cement production are
not enough to mitigate environmental impacts, as expected by society.
Carbon capture and storage, as under discussion by the cement industry, is
not a desirable option due to cost impact that leads to social and economic
implications in developing countries. on the otherhand, binder use optimization
has enormous potential to supply the cement-based materials that society
needs,with much lower environmental impacts.
our results show that it is possible to produce in laboratory conditions
concretes using less than 3 kg m
-3
mPa
-1
of binder. This binder intensity is
almost a third of the current market and lab benchmarks. This can be done
using well-established packing engineering, selected fillers and commercial
Portland cement and dispersants. Scaling up this solution will require
substantial R&D effort, facing problems related to robustness of this systems
and its long-term performance. it also might demand new technologies for
production of better controlled aggregates, especially ultra-fine particles,
more reactive clinkers, new admixtures, at compatible cost.
The authors believe that a
bi
between 5 and 6 kg m
-3
mPa
-1
can be a
feasible target for the market. This will allow a reduction of 30-50% of total
binder intensity, which make possible doubling the cement-based material
production without investing in new kilns and using much additional fuel.
This strategy seems to be economically attractive to the industry since it
means replacing expensive investment and the operational cost of kilns
by new and more sophisticated mills. it will also avoid the need for huge
investment and operational costs of carbon caption and storage.
2.5 Acknowledgements
Bruno Damineli's research is supported by CnPq and CaPeS. The authors
wish to acknowledge the collaboration of CBi Betonginstituten team and
Prof. Björn Lagerblad (KTh-CBi).
