Pozzolanic Activity of Calcined Red Mud


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Title: Pozzolanic Activity of Calcined Red Mud

Author(s): J. Pera and A. Sadr Momtazi

Publication: Special Publication

Volume: 132


Appears on pages(s): 749-762

Keywords: amorphous phase; calcination; compressive strength; dehydration; durability; lime; metakaolin; mortars (material); pozzolanic reactions; red mud; temperature; Materials Research

Date: 5/1/1992

Red mud is a by-product from the aluminum industry. To investigate the possibility of using this waste material as a pozzolan in the cement and concrete industries, tests were carried out to examine the pozzolanic properties of calcined red mud. Red mud was calcined for 5 hr at five different temperatures: 600, 650, 700, 750, and 800 C. Blended portland cements containing 30 or 50 percent of the calcined red mud were studied for hydration products, strength, and durability. The results indicated that the red mud had the maximum reactivity when calcined at 600 C, because on hydration the lime content of the blended cement was considerably reduced. The calcined red mud when used in combination with portland cement contributed to the formation of hydrated alumina-silicates and hydrogarnets. Very good compressive strengths were obtained with the blended cement containing 30 percent calcined red mud. Mortars cast with these blended cements were placed in solutions of seawater and acetic acid. The results indicated good stability of mortars to these environments.