Pozzolanic Reaction Effects of Red Mud on Hygrothermal and Microstructural Properties of Cementitious Composites

Abstract:

The alumina industry produces the red mud (RM) as one of its by-products. The red mud waste has pozzolanic potential, mainly when calcined at 600oC. In this paper, the microstructure of cement pastes constituted by 15% of dry and calcined red mud at 600, 700, 800 and 900oC were investigated by scanning electron microscopy analysis. To assess the evolution of the heat of hydration of pastes produced with until 15% of red mud in replacing the cement was used a semi-adiabatic calorimeter. Water absorption by capillarity and wetting angle tests were realized on mortars constituted by 5 and 10% of red mud in replacement of cement. The images of the microstructures of the pastes produced with red mud showed the formation of the hydration products calcium silicate hydrate, fase AFm (monosulfate) and ettringite. The pastes produced with 5, 10 and 15% red mud showed higher heat of hydration than the reference pastes (only cement). The mortars produced with 5% of dry and calcined red mud at 600, 700, 800 and 900oC showed lower sorptivity than the reference mortar. The results shown that the replacement of the cement by red mud waste influence in the hygrothermal and microstructural properties of cementitious composites.

• Periodical: Key Engineering Materials (Volume 600)
• Pages: 319-328
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.600.319
• Online since: March 2014
• Authors: Eliz Paula Manfroi*, Malik Cheriaf, Janaíde Cavalcante Rocha
• Keywords: Cement, Hygrothermal Property, Microstructure, Red Mud

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