Influence of design durability on concrete columns fire performance

Reinforced concrete structures must be designed to meet minimum durability requirements throughout service life and, as well as in case of a fire, to fulfill fire resistance demands to guarantee user’s safety. This study experimentally evaluated the behavior of column prototypes built of different concrete durability design parameters when exposed to fire, confined by a masonry wall. The evaluation consisted of 16 precast columns of 25 × 25 × 300 cm divided into 4 groups of different concrete mix design. The elements were tested in a standardized vertical furnace for 240 min, exposed to the heating curve from ISO 834. The results showed that the concrete durability parameters influenced the spalling degree and fire resistance performance of the columns. Nevertheless, the concrete cover thickness and the diameter of the longitudinal reinforcing steel bars presented greater influence in fire resistance than concrete mix design.