A Mechanical Investigation on the Recovery of Thermally Damaged Self-Compacting Concrete Using Magnetized Water

Concrete exposed to high temperatures undergoes severe deterioration in strength and microstructural integrity, demanding effective post-fire rehabilitation. This study investigates Magnetized Water (MW) as a re-curing medium for restoring heat-damaged Self-Compacting Concrete (SCC). Specimens prepared with either MW or Normal Water (NW) were subjected to 200°C, 400°C, and 600°C, then re-cured for 28 days in magnetized or plain water. Performance recovery was assessed through compressive, flexural, and bond strength tests, complemented by porosity and Ultrasonic Pulse Velocity (UPV) measurements. The results showed that MW significantly improved recovery compared with NW: after 600°C exposure, re-cured SCC regained 75%–80% of its original compressive strength versus 60%–65% with NW, with a residual strength consistently higher by 5%–15% across all temperatures. The flexural and bond strength recovery exhibited similar trends. MW also reduced porosity by 5%–10% and increased UPV, indicating a denser matrix. Overall, MW re-curing proved an efficient technique for restoring the mechanical properties of thermally deteriorated concrete, highlighting its potential as a practical strategy for post-fire rehabilitation and durability enhancement.