abstract
Red mud, the main waste generated in aluminum and alumina production by the Bayer process, is considered hazardous due to its high pH, according to the Brazilian standard NBR 10004/2004, and worldwide generation of this waste exceeds 117 million tons/year. In this work, non-calcined red mud was used, thus requiring less energy and time and reducing costs, which is the ideal condition for reusing wastes. Mortars containing 30 wt. (%) of cement substituted by red mud showed higher strength of hardened products. The pozzolanic activity index was evaluated based on physical and mechanical parameters (Brazilian NBR 5751 and NBR 5752 standards) and on a chemical analysis (European EN 196-5 standard). A comparison of the reference mixture (without red mud) and the results obtained with red mud confirm the potential of non-calcined red mud for use a as pozzolanic additive in cementitious materials. The setting time (according to the MERCOSUL NM 65 standard) tends to increase but workability remains almost unchanged.
keywords
WATER FILTRATION SLUDGE; COAT PLASTERING MORTARS; RICE HUSK ASH; STRENGTH DEVELOPMENT; BAUXITE
subject category
Materials Science
authors
Ribeiro, DV; Labrincha, JA; Morelli, MR
our authors
João António Labrincha Baptista
Full professoracknowledgements
The authors wish to thank CNPq - National Council for Scientific and Technological Development (Brazil), PPGCEM/UFSCar - Postgraduate Program in Materials Science and Engineering at the Federal University of Sao Carlos (Brazil), and UA/DECV - Department of Ceramics and Glass Engineering, University of Aveiro & CICECO (Portugal) - Project FCT-PTDC/CTM/65243/2006, for their support of this research.; This project was not funded by Alcoa Brazil.