Influence of seawater and sea sand on early-age performance and cracking sensitivity of concrete

Abstract

Due to resource constraints, there has been a growing demand for alternative sources of water and sand in construction engineering. Recent advancements in technology, such as the use of fiber-reinforced polymers (FRP) reinforcement or impressed current cathodic protection-structural strengthening (ICCP-SS), have enabled the utilization of seawater and sea sand, garnering significant research attention. The study investigated various aspects of four types of early-age concrete based on the temperature stress testing machine (TSTM) method, including fresh properties, basic mechanical properties, hydration temperature history, restraint stress, autogenous shrinkage, creep, and cracking sensitivity. The results showed that seawater significantly increased the early tensile strength of concrete, while sea sand had the opposite effect. Compared with ordinary concrete, seawater and sea sand increased the early autogenous shrinkage of concrete, and the impact of seawater was more significant. For the early creep of concrete, seawater and sea sand reduced the maximum compressive creep of concrete, and the effect of sea sand was more remarkable. Seawater increased the tensile creep of concrete, while sea sand decreased the tensile creep of concrete. The comprehensive evaluation index indicates that seawater and sea sand have no significant effect on concrete's cracking sensitivity. This research may serve as a valuable reference for the use of seawater and sea sand in concrete.