Experimental investigations of ultra-high performance concrete exposed to natural fires

Abstract

In the fire safety part of Eurocode 2, material properties for conventional concrete (CC) up to a strength class of C 50/60 and high performance concrete (HPC) of strength classes C 55/67 to C 90/105 are provided. These given values were derived from experimental investigations of heated components based on the thermal exposure of the ISO 834 standard fire. Ultra-high performance concrete (UHPC) has not been standardized yet.While the ISO 834 standard fire is only characterized by a heating phase, a natural fire consists of a heating and a cooling phase.In this paper, the investigation of the thermal and thermo-mechanical material properties of UHPC, considering natural fires, is presented. The thermal properties, including the heat conductivity, the specific heat capacity and the temperature-dependent density as well as the mechanical properties like the temperature dependent stress-strain-relation were experimentally determined. In addition for validation purpose, real-scale experiments on columns were carried out.