Effects of seawater and sea sand on early creep of concrete under different stress levels

Early-age creep of seawater sea sand concrete has a profound effect on construction engineering. This study investigates the ramifications of seawater and sea sand on the early-age creep behavior of concrete subjected to different compressive stresses. To discern the impact of seawater and sea sand on deformation, creep tests were conducted. In parallel, mechanical tests, shrinkage deformation tests, and capillary water absorption tests were conducted to elucidate the influence of seawater and sea sand on macroscopic performance. Moreover, mercury intrusion porosimetry and scanning electron microscopy were deployed to scrutinize the concrete's pore structure and microstructure. The findings reveal that seawater and sea sand precipitate augmented shrinkage and creep deformations in concrete, with seawater exerting a more pronounced effect. Furthermore, seawater and sea sand diminish the porosity of concrete, optimizing its pore structure by curtailing the count of large pores and augmenting the number of gel pores and capillary pores, thereby bolstering its durability. Seawater also reduces the critical stress threshold for the manifestation of nonlinear creep in early-age concrete, while sea sand exerts a minimal influence. These insights hold substantial implications for comprehending the influence of seawater and sea sand on the early-age creep of concrete and offer valuable guidance for their practical deployment in engineering projects.