Abstract
This study investigates the potential of spodumene slag (SPS) as a supplementary cementitious material (SCM). Firstly, the comprehensive characterization results show that SPS consists of quartz, gypsum, calcite, lazurite, and alumino-silicates, with 34 % amorphous content. Next, the hydration characterization indicates that SPS has limited self-cementing properties; however, it inhibits the initial dissolution of C3S, C3A, and C4AF due to the gypsum. This inhibition for C3S is counteracted by the dilution effect of SPS. Over time, the hydration degrees of the clinker phases improve as SPS provides additional nucleation sites and retains more free water for cement hydration. Additionally, thermodynamic modelling was established and validated by experimental data to capture the reaction process and phase changes. AFt forms in all systems, but AFm phases decrease and disappear at 40 % and 50 % SPS levels. Engineering tests reveal that 50 % SPS addition extends initial setting time by 60 %, and reduces fluidity by 20 %. Compressive strength remains acceptable up to 20 % SPS replacement, with an activity index of more than 80 %. Overall, SPS shows potential as a supplementary cementitious material, but careful adjustment of replacement levels is essential to minimize its disadvantages.
Published Version
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