The development and use of geopolymers (GPs) considerably increased in the construction industry. This paper assesses the suitability of metakaolin-based GP mortar and concrete mixtures for underwater applications, including the performance comparison to cementitious (CEM)-based materials. Results showed that the flow times and rheological properties of GP mixtures are significantly higher (i.e., about 2 to 5.5-times) than CEM-based ones. This was mostly related to the high viscosity of the alkaline activator that promotes hydrogen bonding and entanglements between interstitial solution and solid particles. The GP mixtures showed no signs of bleeding and remarkably lower levels of washout loss, reflecting excellent stability as well as superior resistance to dilution, erosion, and washout phenomena upon underwater placement. Their residual compressive, flexural, and pull-off bond strengths varied from 65 to 95% (as opposed to 25–70% for CEM-based materials), revealing the suitability of metakaolin-based GPs for underwater placement.

中文翻译：

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基于偏高岭土的地质聚合物在水下应用的适用性

地质聚合物 (GP) 的开发和使用在建筑行业显着增加。本文评估了偏高岭土基 GP 砂浆和混凝土混合物在水下应用的适用性，包括与水泥基 (CEM) 基材料的性能比较。结果表明，GP 混合物的流动时间和流变特性明显高于 CEM 基混合物（即约 2 至 5.5 倍）。这主要与碱性活化剂的高粘度有关，该活化剂促进间隙溶液和固体颗粒之间的氢键和缠结。GP 混合物没有渗出迹象，冲刷损失水平显着降低，反映了优异的稳定性以及在水下放置时对稀释、侵蚀和冲刷现象的卓越抵抗力。