The application of seawater and sea sand concrete (SWSSC) can reduce the construction period and cost of island infrastructure, but it may also bring the risk of alkali-silica reaction (ASR) due to the presence of alkali ions in seawater and sea sand. To compare the characteristics of ASR between SWSSC and seawater and desalinated sea sand (DSS) concrete and investigate the effects of desalinated sea sand on the ASR of SWSSC, the properties and the ASR products of mortar-bars with different desalinated sea sand content were investigated. When the DSS proportion increased from 0% to 100%, the Na⁺, K⁺, and Ca⁺ concentration contents and pH of the specimens decreased by 22.6, 2.0, 45.1 mg·L⁺ and 0.05, and the expansion of mortar bars reduced by 0.16%. Desalination of sea sand could not eliminate the risk of ASR of SWSSC completely. The 14 days expansion of mortar bars with 100% DSS was 0.13%, and the precursors of ASR-P1 were observed by SEM. The experimental results of XRD, FTIR, Raman spectrometer, DTA, SEM, and EDX all showed that with the increase of DSS proportion, the content of Na-shlykovite and ASR-P1 were gradually reduced. A small amount of Mg element in both Na-shlykovite and ASR-P1 was detected by EDX, but the mechanism of Mg element in ASR of SWSSC needs further study. This study can provide a basis for the application of SWSSC in island infrastructure.

中文翻译：

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淡化海砂对海水及海砂混凝土碱硅反应的影响

应用海水和海砂混凝土（SWSSC）可以减少海岛基础设施的建设工期和成本，但也可能因海水和海砂中碱离子的存在而带来碱硅反应（ASR）的风险。为了比较SWSSC与海水和淡化海砂混凝土的ASR特性，研究淡化海砂对SWSSC ASR的影响，对不同淡化海砂掺量的砂浆筋性能和ASR产物进行了研究。 。当DSS比例从0%增加到100%时，试件的Na ⁺、K ⁺、Ca ⁺浓度含量和pH值分别降低22.6、2.0、45.1mg·L ⁺和0.05，砂浆棒膨胀减小0.16%。海沙淡化并不能完全消除SWSSC的ASR风险。100% DSS 砂浆棒14 天膨胀率为0.13%，SEM 观察到ASR-P1 的前驱体。XRD、FTIR、拉曼光谱仪、DTA、SEM、EDX实验结果均表明，随着DSS比例的增加，Na-shlykovite和ASR-P1的含量逐渐降低。EDX在Na-shlykovite和ASR-P1中均检测到少量Mg元素，但SWSSC ASR中Mg元素的作用机制有待进一步研究。本研究可为SWSSC在海岛基础设施中的应用提供依据。