CEMENTITIOUS ACTIVITY OF CALCINED RED MUD

Ano:
2011
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Resumo:

Red mud is a solid waste derived from the processing of bauxite ore to produce alumina. It is considered a hazardous waste due to its high pH. Since cementitious matrices are also strongly alkaline the incorporation of mud might be an interesting reuse solution. This paper describes the use of mud as collected and after calcination at distinct temperatures (450, 650, and 1000ºC) attempting to improve its reactivity. Materials with pozzolanic characteristics may partially replace the cement in mortars or concrete, with known benefits on the durability of products. Mortars containing up to 30 wt% red mud were prepared and characterized. Their pozzolanic activity index was evaluated based on physical and mechanical parameters (EN 4220) and on chemical analysis (EN 196-5). By comparing with a reference mixture without red mud, the obtained results confirm the potential of red mud  as a pozzolanic additive to cementitious materials.