Experimental investigation of fibre reinforced engineered cementitious composite short deep beam under static and impact loading

Engineered Cementitious Composites (ECC), characterised by their remarkable strain-hardening behaviour and superior crack control, are increasingly utilised in infrastructure applications requiring enhanced durability and resilience. However, in deep ECC beam elements, the stress distribution across the depth is non-uniform due to the greater height, leading to a concentration of stresses in certain sections, which may limit the material's ability to exhibit its strain-hardening potential. This study aims to investigate the static and dynamic response of polyvinyl alcohol (PVA) fibre-reinforced ECC short deep beams subjected to three-point bending and impact loading. The experimental program involved casting short deep beam specimens using a PVA-ECC mix, with a 2% volume fraction of PVA fibres. Static three-point bending tests were conducted to assess flexural strength, crack formation, and load-deflection characteristics. For dynamic testing, a drop-weight impact machine was employed to simulate high strain-rate loading in a three-point dynamic bending setup. The primary response parameters, such as peak load, energy absorption, and crack propagation, were recorded under both static and dynamic conditions. The results demonstrated that the ECC beams exhibited a more elastic-brittle failure mode as the deeper sections experienced localised overstressing before significant strain-hardening could occur. In both static and dynamic tests, the primary failure mechanism was a significant flexural crack formed at the centre of the deep ECC beam. These findings highlight the limitations of ECC when used in certain structural elements, particularly deep beam configurations.