Investigation on the dynamic mechanical properties and mesoscopic damage mechanism of alkali-activated seawater and sea sand concrete in marine corrosive environments

The dynamic mechanical behavior of alkali-activated seawater and sea sand concrete (ASSC) in marine corrosive environments were investigated by splitting Hopkinson pressure bar (SHPB) impact experiment. This study investigated how corrosion age, strain rate, and various corrosion environments influence the mechanical characteristics and macroscopic failure behavior of ASSC. Furthermore, a three-dimensional (3D) mesoscopic model was employed to investigate mesoscopic damage mechanism of ASSC. The outcomes indicate that increasing corrosion age intensifies the corrosion effect on concrete, with the dry-wet cycling having a more pronounced erosive impact compared to solution immersion. The dynamic mechanical properties and failure morphology exhibit a pronounced strain-rate effect. Microscopic analysis showed that cracks first developed in the interfacial transition zone (ITZ) before propagating into mortar. As smaller cracks coalesced into larger ones, their progression ultimately led to the fragmentation of the aggregates.