Systematic review of spalling fire resistance and residual capacity in advanced and composite concrete columns exposed to fire

Advanced concrete systems such as HSC, UHPC, RPC, CFST and SRC columns are used in high-rise construction due to their strength, durability and structural efficiency. Their performance is still influenced by explosive spalling, serious degradation of mechanical properties and large reductions in residual load-bearing capacity after fire. The existing fire design rules calibrated for normal strength concrete do not yet integrate the complex thermal and mechanical deterioration mechanisms of advanced concrete systems. Systematic reviews following PRISMA guidelines This PRISMA-guided systematic review addresses this gap. The results show that the addition of 0.9–2.0 kg/m 3 polypropylene fibers decreases the explosive spalling in HSC during the ISO 834 fire. However, their performance in UHPC depends on the mixture composition, moisture content, and heating rate and needs to be evaluated for each formulation. The maximum damage to CFST columns with axial load ratios of 0.3–0.5 and fire resistance ratings of 30 to 90 min was caused by eccentric loading and high slenderness ratios. The residual axial load capacity of UHPC columns after fire was 0.35–0.78 of the initial capacity depending on the axial load ratio, cross-sectional dimensions and fiber dose. The axial strains after fire were 2.3% for CFST columns and 0.5–0.8% for exposed HSC and UHPC columns. Columns exposed to fire in high-rise structural frames may shrink more than columns not exposed to fire. This is the first cross-typology synthesis to clearly distinguish the during-fire resistance from the post-fire residual capacity and to benchmark the data against Eurocode 2, Eurocode 4 and ACI 216.1.