Material Properties of Ultra - High Performance Concrete in Extreme Conditions

Abstract

The Ultra High Performance Concrete (UHPC) is a very promising material suitable for application in special structures. However, the knowledge of performance of this relatively new material is rather limited. The exceptional mechanical properties of UHPC allow for a modification of the design rules, which are applicable in ordinary or high strength concrete. This paper deals in more detail with impact of thermal stress on bond properties between prestressing strands and UHPC and an influence of high temperature to final material properties of different UHPC mixtures. Specimens in the first experimental part were subjected to the cycling freeze-thaw testing. The relationship between bond behavior of both type of material (UHPC and ordinary concrete) and effect of cycling freeze-thaw tests was investigated. The second part of experimental work was focused on mechanical properties of UHPC exposure to the high temperature (Tmax = 200°C to Tmax = 1000°C). Tested mechanical properties were compressive and flexural strengths, the fracture properties will be presented in the next paper. The obtained experimental data serve as a basis for further systematic experimental verification and more accurate information about the significantly higher material properties of UHP(FR)C and its behavior in extreme conditions.