Carbon fiber filaments–enhanced electrothermal curing for integrated curing‑maintenance of mortar in cold regions: Thermal behavior and strength evolution

To address the need for integrated rapid curing and maintenance in cold‑region concrete engineering, this study proposes a carbon fiber filament–enhanced internal electrical curing method (CFF‑IEC), where CFFs are embedded in fresh mortar and energized to generate Joule heat for internal heating. The thermal mechanisms and temperature‑control measures of CFF‑IEC mortar were analyzed based on thermodynamics and heat transfer principles. The study systematically investigated temperature evolution characteristics under varied CFF specifications, power densities, specimen dimensions, and surrounding temperature. Additionally, the effects of two key process parameters (power density and curing duration) on the development of compressive and flexural strengths were evaluated. Test results demonstrate that under ambient conditions, CFF‑IEC effectively regulated internal thermal fields, with stable temperature profiles and heating rates validating its thermal regulation efficacy, while significantly enhancing early‑age compressive and flexural strengths compared to standard curing (SC). Critically, even at −10℃, supplementary top insulation synergized with CFF‑IEC under optimized curing parameters to maintain thermal stability, which translated to remarkable early‑age strength development: 1 d compressive (22.42 MPa) and flexural (5.51 MPa) strengths increased by over 200% and 150%, respectively, relative to SC. Notably, the combination of 10 W/m power density and high‑performance insulation achieved early strength gains comparable to those under higher power settings, with reduced energy consumption. These findings confirm that the proposed CFF‑IEC method enables efficient curing‑maintenance integration, offering a practical and energy-efficient solution for cold‑region cementitious material applications. • A novel Carbon fiber filaments‑enhanced electrothermal curing method is proposed to achieve curing‑maintenance integration for cold‑region mortar. • Thermal mechanisms and temperature‑control strategies of CFF‑IEC are comprehensively analyzed. • The effects of CFF‑IEC parameters on mortar’s strength development under varied ambient temperatures are systematically investigated.