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This study explores the potential of the granite residue to be applied as a supplementary cementitious material. Furthermore, the efficiency of grinding methods in the improvement of the residue reactivity was also evaluated. The granite residue was collected in a facility located in Brazil and used as a Portland cement replacement with a substitution rate of 25% in mass. The residue was submitted to wet, dry and additive dry grinding methods, with several different times. The cement-based composites were characterized by quantitative X-Ray diffraction using the Rietveld's method, thermogravimetric analysis, and compressive strength. In conclusion, there was observed a higher efficiency of the wet grinding method, followed by an increase in compressive strength results as grinding time increased. Furthermore, the portlandite content was lower in the cement-based composite with granite residue, especially in the samples ground for 60, 120, and 180 minutes; a fact that summed up with other results for the pozzolanic potential of the granite residue.

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In this study, synthesis, microstructural characteristics, mechanical properties, and environmental compatibility of alkali‐activated binders derived from iron ore tailings (IOT)—with partial replacement with metakaolin (MK)—were investigated. The binders were produced with a NaOH solution, IOT, and MK. A thermal cure at 100°C was used and the MK was applied as a partial replacement of IOT in three proportions (10, 20, and 30 wt%). The IOT‐based specimens presented an average of 98.0 and 18.0 MPa at 7 days age of curing for compressive and flexural strength, respectively. The mechanical properties of the alkali‐activated binders with MK decreased as the substitution ratio increased. By the microstructural analysis, it was found a zeolite‐type phase in alkali‐activated IOT, while in the binders blended with MK, three new mineral phases were identified. Furthermore, Fourier transform infrared, quantitative X‐ray diffraction, and environmental analysis suggest that the Fe species present in IOT acted in the alkali‐activation reaction.

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