In-flight vitrification of granitic aggregate: Characterization and performance of a scalable supplementary cementitious material

Abstract

Using supplementary cementitious material (SCM) to replace clinker is the cheapest and most effective way to lower CO2 impact of concrete, but supply of conventional SCMs is not currently sufficient. Manufactured SCMs must scale to help meet demand. Traditional calcination approaches up to 1000 °C are only able to activate mineral groups like hydrous clays and zeolites that are not available in all markets. To manufacture SCM from even more abundant and widespread lithologies, a new in-flight vitrification technique was developed. Microspherical glassy SCM was made from archetypal granitic rock sourced from low-value construction aggregate. Vitrified granitic SCM has excellent pozzolanic reactivity compared to a well-known commercial Class F fly ash, as measured by strength activity index of mortar, R3 calorimetry, rapid alkali silica reactivity testing, and realistic concrete mix designs. Aggregate mines with silicate mineralogy are an overlooked feedstock resource for vitrified SCM manufacture with this new technique.