Analyzing Performance of Partially Encased Composite Columns with Steel Wool and Carbon Fiber

Steel wool (L/d = 70, 0.3%) and carbon fiber (0.6%) alone raised the 28-day compressive strength by 11.6% and 15.9%, but the hybrid of 0.50% CF + 0.50% SW performed best, giving about 19% higher strength, 18–58% higher residual strength after exposure to 400–800 °C, lower mass loss, and a core temperature 115–120 °C below that of plain M30. The PECC with hybrid infill carried 14.9% more load than the plain-concrete PECC and deformed about 135% more, while the ANSYS model matched the tests and showed slower heat transfer to the steel core. Load-bearing fire tests on PECCs are recommended as future work.

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