Mechanical properties of various concrete after high temperature exposure Mechanical property of various types of concrete after high temperature exposure is investigated. Considering compressive strength requirement for a vertical element in high rise building, concrete specimens with various design strengths of 35, 80, 100, and 150 MPa were tested. Particularly, the influence of incorporated steel fiber on fire resistance is of interest in this study. Experimental results show that the fire resistance depends on the design strength and steel fiber content. Normal strength concrete (NSC) of a design strength of 35 MPa or high performance concrete (HPC) of 80-100 MPa does not spall when exposed to 100-400 °C of temperature. However, an explosive spalling occurs at 300 °C when the HPCs contain 1 vol. of steel fiber. Ultra-high performance concrete (UHPC) of a design strength of 150 MPa and 1.5 vol. of steel fiber also shows dramatic spalling at 300 °C. The experimental results found in this study can contribute to a better understanding of the behaviors of HPC and UHPC under fire and the role of steel fiber on the fire resistance.