Supplemental Materials: Absorption-Dominant Electromagnetic Shielding in Cementitious Composites Containing Steel Machining Swarf

Supplemental Materials for the manuscript "Absorption-Dominant Electromagnetic Shielding in Cementitious Composites Containing Steel Machining Swarf," submitted to the ASCE Journal of Materials in Civil Engineering (manuscript MTENG-26026, in review). The study investigates the direct valorisation of as-received mild steel machining swarf as a functional additive for electromagnetic interference (EMI) shielding cementitious composites, combining mechanical characterisation of concrete mixes (5–20% fine-aggregate replacement), X-band (8.2–12.4 GHz) waveguide shielding measurements on cement-paste specimens (0–20 wt% swarf of cement mass), life cycle assessment with the swarf-preparation phase internalised, and multi-objective composition selection. This deposit contains: Section S1 — Electromagnetic shielding theory and parameter extraction: shielding-effectiveness definitions (Eqs. S1–S4), the Nicolson–Ross–Weir (NRW) formulation, power-coefficient definitions, and the shielding-mechanism schematic (Fig. S1). Section S2 — Electromagnetic parameters of the NRW-stable compositions: complex permittivity spectra (Fig. S2), dielectric loss tangent (Fig. S3), NRW instability discussion for the 15 wt% composition, and magnetic permeability observations. Table S1 — Life cycle inventory of the steel swarf concrete mixes recomputed from as-batched proportions (kg/m³), absolute-volume method. Citations in this document refer to the reference list of the main article. These materials supplement but are not required for understanding the main article.