Print version ISSN 0366-6913
RIBEIRO, D. V.; SILVA, A. M. S.; LABRINCHA, J. A. and MORELLI, M. R.. Study of alkali-silica reactions associated with the use of red mud in plastering mortars. Cerâmica [online]. 2012, vol.58, n.345, pp. 90-98. ISSN 0366-6913. http://dx.doi.org/10.1590/S0366-69132012000100015.
The incorporation of industrial wastes in cementitious matrices, with the goal of inertization, is an alternative of reuse that has been extensively studied in recent years. In this paper, the red mud, the main waste generated in aluminum and alumina production by the Bayer process from bauxite ore and considered "hazardous" due to the high pH, was studied. Despite the use of this waste have been reported in previous studies, some pathologies may be associated with its use, due to high concentration of alkali ions (mainly sodium), favoring the alkali-silica reactions (ASR) and the difficulties of molding (rheology) because of high fineness of this waste. Despite these potential problems arising from the indiscriminate use of red mud as an addition to mortars and concrete, there are few studies that contemplate this problem, and is the focus of the present work. The rheological properties of mortars were studied using a rheometer, and the evaluation of ASR was evaluated, according to ASTM C 1260-07 and NBR 11582 standards. The results were very satisfactory as to the mortars behavior concerning the ASR, despite the high alkali concentration in red mud, with great rheological influence.
Keywords : cement; mortar; red mud; ASR; durability; rheology.