Calcium sulfoaluminate (CSA) cements have remarkable environmentally friendly features which can be further enhanced by using industrial wastes and by-products as sources of raw materials. CSA clinkers were obtained by heating for two hours in a laboratory electric oven, at temperatures ranging from 1150° to 1300°C, raw mixes consisting of calcium carbonate or limestone, alumina or bauxite, fluidized bed combustion waste, FGD gypsum and, as additional sources of Al2O3, red mud or pulverized fly ash. The best behaviour in terms of reactants conversion and selectivity degree towards and C2S was obtained when pfa was used instead of red mud. Two high-performance laboratory-made CSA cements (obtained by adding 14-15% of FGD gypsum to two of the best synthetic clinkers), paste hydrated from 3 hours to 28 days, showed a hydraulic behaviour similar to that of CSA industrial cements, when investigated through XRD, DTA-TGA and SEM analyses as well as mercury porosimetry.
Synthesis, Hydration Properties and Environmentally Friendly Features of Calcium Sulfoaluminate Cements
MARROCCOLI, Milena;TELESCA, ANTONIO;VALENTI, Gian Lorenzo
2007-01-01
Abstract
Calcium sulfoaluminate (CSA) cements have remarkable environmentally friendly features which can be further enhanced by using industrial wastes and by-products as sources of raw materials. CSA clinkers were obtained by heating for two hours in a laboratory electric oven, at temperatures ranging from 1150° to 1300°C, raw mixes consisting of calcium carbonate or limestone, alumina or bauxite, fluidized bed combustion waste, FGD gypsum and, as additional sources of Al2O3, red mud or pulverized fly ash. The best behaviour in terms of reactants conversion and selectivity degree towards and C2S was obtained when pfa was used instead of red mud. Two high-performance laboratory-made CSA cements (obtained by adding 14-15% of FGD gypsum to two of the best synthetic clinkers), paste hydrated from 3 hours to 28 days, showed a hydraulic behaviour similar to that of CSA industrial cements, when investigated through XRD, DTA-TGA and SEM analyses as well as mercury porosimetry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
