Title: Characterization of Quarry Waste Powder for Calcined Clay Production
Author(s): Gabriela Coelho dos Santos, Natalia Alderete, Yury Villagrán-Zaccardi, Nele De Belie
Publication: Symposium Paper
Appears on pages(s): 29-40
Keywords: quarry residue, characterization, SCM, pozzolanic activity, sustainability
This paper analyzes waste fines generated during the mining, crushing, and washing of aggregates in quartzite quarries (Mar del Plata, Argentina). The waste fine consists mainly of a mixture of quartzite and clay. The characterization of the materials included chemical analysis, XRD, TGA, particle size distribution, morphology, and composition of particles by SEM-EDS. Both the dry raw materials and the calcined material (temperatures of 500º C, 700º C, and 950º C) were analyzed. The pozzolanic activity of the calcined powders at different temperatures was evaluated by the modified Chapelle method. The original composition of the material, consisting of angular quartz, kaolinite "face to face" and laminar illites, was modified as calcined clays vary in their morphology and mode of aggregation due to the effect of temperature. The result of the TGA showed some limited loss on ignition (3%) between 400º C and 800º C, reflecting the dehydroxylation of clays. The pozzolanic activity effectively increased with increasing calcination temperature. Therefore, the material is considered to have pozzolanic activity when thermally activated.