Flexural fatigue performance of a high-thixotropy UHPC

Abstract

This research aims to perform a comparison of the mechanical response and the fatigue behaviour of two Ultra-High Performance Concrete (UHPC) mixtures subjected to bending loads: a regular UHPC and a high-thixotropy UHPC. The same materials were used in both mixtures and the only difference was the proportions of water and additive. Rheological tests were performed to validate the thixotropy of mixtures in fresh-state. Additionally, image analysis was applied to get fibre distribution and orientation from beam-cut slices. Thus, the Image pixel complete colour structure (RGB) was analysed to avoid greyscale transformations because of its loss of information. Finally, three-point bending tests were conducted over pre-cracked beams to establish a fatigue equation for the mixtures. Experimental results showed that high-thixotropy UHPC has mechanical properties comparable to regular UHPC.