Behavior of cracked cross-section of fibre reinforced UHPFRC under sustained load

Abstract

In this paper, the work done at TU Kaiserslautern for a better understanding of the behaviour of cracked ultra-high performance fibre reinforced concrete (UHPFRC) is reported. UHPC is a material with a very high compressive strength. A ductile behaviour and a rather good tensile strength are achieved by addition of fibres. While the short time resistance can be easily evaluate with laboratory tests, the discussion concerning the long-term behaviour is still open. A sustained load test rig with lever arms for axial tension tests was built. Dog-bone specimen and prisms were loaded for axial and bending creep tests investigating many different parameters. Aim of this research is to give a systematic characterisation of the problem and find out if the material can creep up to failure and at which load level. Required consequences for design of UHFRC should be defined. The computed tomography was used for a direct observation of the fibre inside the concrete. A correlation between experimental results with large scatter and specimen fibre distribution and orientation is sought in this way.