Experimental Investigation on Material Properties of Ultra - High Performance Fiber Reinforced Concrete in Extreme Conditions

The Ultra - High Performance Fibre Reinforced Concrete (UHPFRC) is a very promising modern cementitious material suitable for application in special structures. The knowledge of performance of this relatively new material is limited. This paper deals in more detail with impact of extreme conditions (it means thermal loading) on bond properties between prestressing strands and UHPFRC and an influence of elevated temperature to final material properties of different UHPFRC mixtures. The first part of experimental work was focused on mechanical properties of UHPFRC and UHPC exposure to the high temperature (T-max = 200 degrees C - 1000 degrees C). Tested residual mechanical properties were compressive and flexural strengths, the fracture properties will be presented in this paper. Specimens in the first second 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 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.