Reusing waste toner powder as functional additives for alkali-activated slag

The incorporation of waste toner powder (WTP), a recognized hazardous waste, into cementitious materials as a functional additive offers a cost-effective disposal method and a sustainable utilization approach. This study examines the feasibility of integrating WTP into alkali-activated slag (AAS) compositeswith a focus on the potential of WTP to enhance the material properties of these composites. Microstructural analysis using SEM confirmed that the inclusion of a dispersing agent (PCE) improved the dispersion of WTP, minimizing particle agglomeration. Rheological tests indicated that increasing WTP content reduced flowability and increased plastic viscosity, though PCE pretreatment helped mitigate these effects. Compressive strength results showed a reduction in strength with higher WTP content, likely due to the limited involvement of WTP in the hydration process. Nevertheless, the strength levels remained sufficient for practical applications. Electrical resistivity measurements demonstrated increased conductivity with higher WTP content, indicating potential self-sensing capabilities. Leaching tests revealed that the AAS composite effectively immobilized heavy metals, ensuring safety for landfill disposal. XRD and MIP analyses provided further insights into WTP's impact on hydration dynamics and pore structure, with PCE enhancing pore refinement. This work introduces a novel valorization strategy for hazardous WTP by developing multifunctional AAS-based composites with potential self-sensing properties. These findings offer practical implications for smart infrastructure development and sustainable waste management in the construction industry.