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.

中文翻译：

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不同应力水平下海水和海砂对混凝土早期徐变的影响

海水海砂混凝土的早期徐变对建筑工程有着深远的影响。本研究研究了海水和海沙对不同压应力下混凝土早期蠕变行为的影响。为了了解海水和海沙对变形的影响，进行了蠕变试验。同时进行了力学测试、收缩变形测试和毛细管吸水测试，以阐明海水和海砂对宏观性能的影响。此外，还采用压汞孔隙率测定法和扫描电子显微镜来检查混凝土的孔隙结构和微观结构。研究结果表明，海水和海砂会加剧混凝土的收缩和蠕变变形，其中海水的影响更为明显。此外，海水和海砂减少了混凝土的孔隙率，通过减少大孔的数量、增加凝胶孔和毛细孔的数量来优化其孔结构，从而增强其耐久性。海水还降低了早期混凝土非线性徐变表现的临界应力阈值，而海砂的影响很小。这些见解对于理解海水和海沙对混凝土早期徐变的影响具有重要意义，并为其在工程项目中的实际部署提供了宝贵的指导。