ABSTRACT
This paper attempts to propose the process for prediction of residual internal force of column member
with ultra-high-strength concrete (UHSC) by connecting material mechanical properties at elevated
temperature and fire resistance performance of column member through experimental results of
mechanical properties, spalling properties, internal force degradation of reinforced concrete column
member and residual internal force of UHSC. For evaluation on mechanical properties at elevated
temperature of UHSC, 100×200mm cylinder specimen of 200MPa was heated to 700°C by 1°C/min.
The ratio of compressive strength at room temperature to compressive strength at elevated temperature
was measured. Comparison evaluation between experimental results and previously presented
compressive strength properties of normal strength concrete (NSC) and high strength concrete was
carried out. Column member with 200MPa concrete was heated by ISO-834 standard heating curve for
3hours. Internal force degradation and fire resistance performance of column member was evaluated by
measuring internal temperature and axial deformation. After heating, residual load was evaluated after
24 h of post-test cooling. Prediction process of residual internal force of UHSC column was proposed
by deriving model with experimental results of residual mechanical properties and spalling properties
of UHSC at elevated temperature. As results, internal force degradation of UHSC by elevated
temperature occurred more than that of NSC. In the test for fire resistance performance of column, 26%
of section was lost due to spalling, however, residual internal force was 52% of design axial load.
건설재료시공학연구실