A review on seawater sea-sand concrete: Mixture proportion, hydration, microstructure and properties

Extensive studies have been conducted on seawater sea-sand concrete (SSSC) in recent years due to the shortage of freshwater and river-sand in many coastal areas. This paper reviews the properties of seawater and sea-sand and their effects on hydration, microstructure and properties of concrete. The relationship between mixture proportion and the hardening properties and durability of SSSC is discussed and optimization of mixture proportion for better performance of SSSC is studied. The results indicate that the utilization of seawater and sea-sand in preparation of concrete is very promising with accelerated cement hydration, improved pore structure and durability only if suitable material composition is applied to mitigate the chemical corrosion caused by sea salt. For sea-sand concrete, it is the shells and organic substances that matters for properties of concrete. The usage of supplementary cementitious materials (SCMs) with high aluminum content has a remarkable improvement on properties of SSSC due to the pozzolanic reaction and chloride binding. SSSC with superior properties can be obtained when appropriate W/B ratio, SCMs and chemical admixtures contents are employed according to the properties of seawater and sea-sand.