AbstractThe static and dynamic fracture behavior of high-strength fiber-reinforced seawater sea-sand (SWSS) concrete was investigated by conducting fracture toughness and drop-weight impact tests. The results were compared with those of freshwater normal-sand (FWNS) and SWSS plain concretes. Polypropylene (PP) and polyvinyl alcohol (PVA) fibers with different fiber ratios (0.1%–0.5%), were used for reinforcement. A poor brittle failure was found for plain SWSS and FWNS mixes. Compared with FWNS, SWSS concrete had higher fracture toughness and impact energy values. Incorporation of fibers, especially PP fiber, significantly improved both static and dynamic fracture behavior of the plain SWSS concrete. PP fiber pull-out led to a considerable enhancement of ductility, residual strength, and fracture and impact energy values. The fibers in SWSS concrete with a high percentage of PP fibers can be used as partial and, in some cases, total substitution for conventional reinforcement. On the other hand, due to their chemical bonding with cement products PVA fibers mostly improved the precracking properties of the SWSS mix, such as flexural strength and impact resistance at first crack formation, rather than postcracking properties.