Influence of thermally activated artificial concrete fines composition on mortar strength development

The study explores the use of thermally activated concrete fines as substitution for cement to recycle mineral waste and reduce emissions. Concrete fines from waste recycling have a significant impact on compressive strength, with considerable variation due to their varying compositions. In the present study, 12 artificial concrete fines with varying compositions are thermally activated and assessed for their strength contribution. Increasing aggregate content within artificial fines results in a decrease in compressive strength, with aggregate mineralogy and binder composition having a major impact. Ultimately, this study proposes a model for predicting the impact of fines composition on compressive strength based on mass loss during dehydration. For thermally activated cement paste, the new model proposes no influence on compressive strength compared to the reference ( k = 1 . 0 ). Paste precursors containing hydration products from alternative binders may even surpass the reference ( k > 1 . 0 ), while an increasing amount of inert aggregates reduces strength ( k < 1 . 0 ). • Strength contribution of fines correlates with mass change from dehydration. • The presence of aggregates reduces mass loss and strength contribution. • Siliceous aggregates have a higher strength contribution than calcitic ones. • Fines with slag or fly ash exhibit a higher strength contribution than OPC fines.