Investigations on Cyclic Flexural Behavior of Fiber Reinforced Cementitious Composites Using Digital Image Correlation and Acoustic Emissions

Superelastic shape memory alloys (SE SMAs) are smart materials that recover 6-8% of inelastic strains upon unloading and exhibit good energy dissipation. In this study, the mechanical behavior of cementitious composites, reinforced with steel and SE SMA fibers, under flexure was examined. Fiber reinforced concrete, with a total fiber volume ratio of 0.6%, was prepared and a third point bending flexural test was conducted using an incrementally increasing displacement loading protocol. DIC was used to measure the strain and displacement contours and detect the crack width propagation. The results of the cyclic flexural testing were analyzed to assess the re-centering and crack recovery capabilities. Acoustic emissions (AE) were monitored using AE transducers to predict the failure modes (fiber pullout/matrix cracking). The AE were analyzed using average frequency, cumulative energy, duration and hits. The correlation between the DIC and AE was investigated. The results suggest that the crack data can be correlated with AE.