Feasibility of low-carbon electrolytic manganese residue-based supplementary cementitious materials

In this work, the electrolytic manganese residues (EMR) were used as sulfate activators for fly ash and granulated blast-furnace slag to fabricate highly reactive supplementary cementitious materials (SCMs). The findings promote the im-plementation of a win-win strategy for carbon reduction and waste resource utilisation. The effects of EMR dosing on the mechanical properties, microstructure and CO2 emission of the EMR-doped cementitious materials are investi-gated. The results show that low dosing EMR (5 %) produced more ettringite, fostering early strength development. The fly ash-doped mortar strength increases and then decreases with the addition of EMR from 0 to 5 % to 5-20 %. It was found that blast furnace slag contributes less to strength than fly ash. Moreover, the sulfate activation and the micro-aggregate effect compensate for the EMR-induced dilution effect. The significant increase in strength contribu-tion factor and direct strength ratio at each age verifies the sulfate activation of EMR. The lowest EIF90 value of 5.4 kg center dot MPa-1 center dot m3 was achieved for the fly ash-doped mortar with 5 % EMR, suggesting the synergistic effect between fly ash and EMR optimised the mechanical properties while maintaining lower CO2 emissions.

Automated summary

In this study, electrolytic manganese residues were used as sulfate activators to fabricate highly reactive supplementary cementitious materials. The results showed that appropriate dosing of electrolytic manganese residues promoted early strength development and compensated for the dilution effect through sulfate activation and micro-aggregate effect.