Page 369 - Handbook of Thermal Analysis of Construction Materials

References 345

consumed in a mixture with a 30% red mud replacement. The hydrated
products consisted of C-S-H, hydrated aluminum silicates and hydrogarnets.
The blended cement showed better durability to acids and sea water
compared with the untreated cement.
Pressurized fluidized bed combustion (in a coal-fired thermal
plant) offers efficiency and reduction in environmental loads. The coal ash
produced in this process is a consequence of firing a mixture of pulverized
limestone and coal. In this process, the mixes are burned at a lower
temperature than that carried out in the conventional power plant which
produces fly ash. There is a possibility of utilizing coal ash as an admixture
in concrete. Thermal analysis of the hydration products obtained at differ-
ent w/s ratios from coal ash-cement pastes indicated substantially lower
amounts of lime than that estimated in pure cement pastes. [98] This indicates
that lime in the mixes is consumed by the coal ash through a pozzolanic
action. In another study, the residue of fluidized combustion of bituminous
and sub-bituminous coal was tested for its hydraulic properties. [99] The
residue had a carbon content of 0.1 to 10% and compounds such as iron
oxide, calcite, feldspar, anhydrite, and quartz. DTA/TG was successfully
used for determining the residual carbon content, CaCO , and anydrite. [15][99]
3

REFERENCES

1. Hewlett, P. C., (ed.), Lea’s Chemistry of Cement and Concrete, p. 1053,
John Wiley & Sons, New York (1998)
2. Swamy, R. N., (ed.), Cement Replacement Materials, p. 259, Surrey
University Press, Glasgow (1986)
3. Taylor, H. F. W., Cement Chemistry, p. 459, Thomas Telford, London
(1997)
4. Sarkar, S. L., and Ghosh, S. N., (eds.), Mineral Admixtures in Cement and
Concrete, p. 565, ABI Books Priv. Ltd., New Delhi, India (1993)
5. Muller, C., Hardtl, R., and Shielbl, P., High Performance Concrete with Fly
rd
Ash, 3 Int. Symp. on Advances in Concr. Technol., (V. M. Malhotra, ed.),
SP-171:173–200 (1997)
6. Ghosh, S. N. (ed.), Advances in Cement Technology, p. 804, Pergamon
Press, New York (1983)