A comparative study between ultra-high-performance concrete structures and normal strength concrete structures exposed to fire

The use of ultra-high-performance concrete (UHPC) in civil infrastructure is increasing due to its numerous advantages compared to normal strength concrete (NSC). In this research, thermal analysis of NSC and UHPC beams and columns was developed to understand and compare the fire performance of these structures. A numerical analysis was performed using finite element (FE) modeling with ABAQUS software. Compared to NSC, UHPC structures in some cases have lower fire resistance due to their slender cross-sections and unfavorable thermal properties and mechanical capacity degradation due to temperature effect. The results show that UHPC structures experience significantly higher cross-sectional temperatures when exposed to fire compared to NSC. The results are particularly relevant for high-rise buildings, where fire safety requirements are more stringent and the use of UHPC is attractive, leading to an unprecedented contradiction. Alternative strategies for the application of UHPC, such as the contradictory increases in cross-section or the use of fire protection coatings, must be considered. In some cases, NSC may be more attractive as a structural material than UHPC if structural fire design requirements are taken into account.