Post-fire rehabilitation of reinforced concrete columns: effectiveness of ferrocement jacketing under different cooling regimes

Abstract Fire exposure severely reduces the strength of reinforced concrete (RC) columns, with residual performance strongly influenced by cooling regimes. This study examined 27 columns subjected to 150–600 °C, cooled in air or water, and retrofitted with ferrocement jacketing using locally available materials. Results showed that air cooling preserved higher residual strength than water quenching, while ferrocement jacketing restored up to approximately 80% of original capacity at 150 °C (air cooled) and about 50% under water cooling. At 300–450 °C, retrofitting improved ductility and delayed failure but only partially recovered strength, and at 600 °C, recovery was limited to deformation capacity. Comparative analysis with FRP, steel, and concrete jacketing from previous studies highlights ferrocement’s advantages of low cost, ease of application, and local adaptability, making it a viable rehabilitation strategy for moderate fire damage, though advanced systems may be required for severe exposure.