The potential sustainability and cost-effectiveness of seawater sea-sand concrete (SWSSC) have sparked widespread research interest and prompted extensive applied studies. However, the understanding of the alkali-silica reaction (ASR) in SWSSC is still lacking. In this work, the long-term ASR of SWSSC and the characterization of ASR gel was investigated. The result illustrated that the specimens mixed with either seawater or NaCl solution would show long-term ASR expansion, degrading the pore structure and forming ASR cracks. With the increase of sodium ion concentration, higher expansion and larger crack width were observed. Nanoindentation tests further revealed the evolution of ASR damage. The ASR gel produced in SWSCC had a white appearance and consisted of numerous interwoven sheet-like structures forming a honeycomb-like network. Its elastic modulus and hardness were 14.77 GPa and 0.35 GPa, respectively. In addition, the increase of sodium ion concentration would promote the formation of ASR gel but reduce the polymerization degree and the average chain length of the C–S–H, increasing the amount of gel pores.

中文翻译：

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海水海砂混凝土中碱硅反应行为的长期研究


海水海砂混凝土（SWSSC）潜在的可持续性和成本效益引起了广泛的研究兴趣并促进了广泛的应用研究。然而，对SWSSC中碱硅反应（ASR）的了解仍然缺乏。在这项工作中，研究了 SWSSC 的长期 ASR 和 ASR 凝胶的表征。结果表明，与海水或氯化钠溶液混合的试件会出现长期的ASR膨胀，破坏孔隙结构并形成ASR裂纹。随着钠离子浓度的增加，观察到更高的膨胀和更大的裂纹宽度。纳米压痕测试进一步揭示了 ASR 损伤的演变。 SWSCC 生产的 ASR 凝胶具有白色外观，由许多交织的片状结构组成，形成蜂窝状网络。其弹性模量和硬度分别为14.77 GPa和0.35 GPa。此外，钠离子浓度的增加会促进ASR凝胶的形成，但会降低C-S-H的聚合度和平均链长，增加凝胶孔的数量。