Mechanical Properties of Seawater Sea-Sand Concrete Exposed to Daily Temperature Variations

The durability of a concrete structure is affected by temperature cycles that occur during the structure’s service life. This paper presents an experimental and theoretical study of the mechanical properties of seawater sea-sand concrete when exposed to temperature variations. By using compressive tests on cylindrical concrete specimens, the effects of thermal cycling (e.g., the amplitude of temperature variations and cycling times) on the mechanical properties of seawater sea-sand concrete, such as failure modes, compressive strength, stress–strain relationship, Young’s modulus, ultimate strain, Poisson’s ratio and toughness are investigated. Microstructures of both unconditioned and conditioned concrete samples are examined by using scanning electron microscopy (SEM) to understand the mechanisms behind the strength changes. Finally, the stress–strain model is proposed for seawater sea-sand concrete subjected to daily temperature variations, and the proposed model is verified by the experimental data.