Résumé
Developing multifunctional, self-heating cementitious composites is a key strategy for creating sustainable infrastructure and mitigating the environmental damage caused by de-icing salts. We fabricated composites using Portland cement and high-structure acetylene black as a conductive nanofiller (0–7 wt%) and analyzed their performance through systematic thermo-electric measurements, scanning electron microscopy, and a two-regime percolation model. The results demonstrate a percolation threshold (pc) at approximately 2.5 wt% AB, above which the electrical conductivity increases by eight orders of magnitude to nearly 1 S/m. Our analysis reveals a distinct microstructural transition from a rapid-onset percolation regime (low exponent t1) to a complex network consolidation regime (higher exponent t2). In Joule heating tests, the composites achieved a maximum temperature increase (ΔTmax) of approximately 50 °C. Crucially, the maximum temperature gain plateaus at filler concentrations above 5 wt%, revealing a complex, non-linear relationship between electrical conductivity and steady-state thermal output. A quantitative comparison with literature benchmarks reveals that the AB-based composite possesses a remarkably high intrinsic heating efficiency, orders of magnitude greater than other carbon-based systems. This work provides a quantitative framework that directly links filler content, microstructure, and multifunctional performance in cement-nanocarbon composites, offering a basis for optimizing these materials to achieve both rapid heating and energy efficiency for practical applications.
•AB’s highly branched aciniform morphology outperforms conventional furnace black.•Two-regime model shows hyper-efficient AB networking then costly consolidation step.•AB composites exhibit higher intrinsic heating efficiency than comparable systems.•Joule heating shows a trade-off: fastest heating doesn’t produce highest temperature.•Scaled-up prototypes show strong heating and up to 150× higher intrinsic efficiency.