Performance of Normal Strength Concrete Slab Strengthened with High-Performance Concrete After Exposure to Elevated Temperature

Abstract Reinforced concrete as the most important construction material suffers from long-term deterioration due to different exposure conditions. Fire attack is a critical condition it can lead complete collapse of structure. On other hand, repair and strengthening existing structures have become necessary both technically financially. Moreover, since high-performance concretes (HPCs) are extensively used repairing or materials for structures, their performance after elevated temperature needs be investigated. Therefore, this study directed investigate post-fire flexural behavior RC slabs cast with traditional normal strength (NSC) strengthened HPC. Twenty-one were prepared tested including casting full thickness same mixture (single-concrete slabs) composite (cast NSC HPC). Different variables considered; using high concrete, 30% fly ash, slag, 0.5% polypropylene, steel fibers, hybrid fibers (0.5% + polypropylene), reinforcement ratio, side exposed (tension compression), joining HPC layer (shear studs epoxy resin). The required 600°C 2 h. results show that slab in tension compression by remarkably enhanced slab’s temperature. Specially, containing when recorded highest cracking load, ultimate stiffness, toughness, ductility index compared slab, increases 92.8%, 116%, 157%, 335%, 86.9%, respectively.