Abstract Nano-SiO2 is a non-toxic, tasteless, and pollution-free material with hydroxyl groups that facilitate the adsorption of water on its surface. Nano-SiO2 is characterized by small particle size, high purity, low density, large surface area, and good dispersion properties. In addition, nano-SiO2 has excellent stability, reinforcement, thixotropy, and optical and mechanical properties. The additive of nano-SiO2 can enhance the mechanical properties and microstructure of concrete. Therefore, nano-SiO2 is widely used as an additive in the field of building materials. Geopolymers have excellent mechanical properties, acid–alkali resistance, fire resistance, and high-temperature resistance. In addition, mineral waste and construction waste can be used as raw materials for geopolymers. Therefore, geopolymers have the potential to substitute ordinary Portland cement and have good prospects for application as construction materials. The application of nanomaterials in geopolymer products has shown that nano-SiO2 is effective in increasing the rate of geopolymerization reaction and reducing the setting time of geopolymers in a controlled quantity. Related results indicate that an appropriate quantity of nano-SiO2 can make the microstructure of fly ash-based geopolymers denser and produce higher mechanical strength. In this study, based on the mechanism of geopolymerization, the effects of nano-SiO2 on the properties of fly ash-based geopolymers including compressive strength, microstructure, hardening properties, shear bond strength, durability, and practical applications have been summarized. This study can provide a basis for understanding the effects of nano-SiO2 on the mechanical properties and durability of fly ash-based geopolymers.

中文翻译：

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纳米SiO2添加剂粉煤灰基地质聚合物性能综合评价

摘要 纳米SiO2是一种无毒、无味、无污染的材料，其表面带有羟基，有利于水的吸附。纳米SiO2具有粒径小、纯度高、密度低、比表面积大、分散性好等特点。此外，纳米SiO2具有优异的稳定性、增强性、触变性以及光学和机械性能。纳米SiO2添加剂可以增强混凝土的力学性能和微观结构。因此，纳米SiO2被广泛用作建筑材料领域的添加剂。地质聚合物具有优异的机械性能、耐酸碱、耐火性和耐高温性。此外，矿物废料和建筑废料可用作地聚合物的原料。所以，地聚合物具有替代普通硅酸盐水泥的潜力，作为建筑材料具有良好的应用前景。纳米材料在地质聚合物产品中的应用表明，纳米SiO2可有效提高地质聚合物的反应速率，并在可控的量下减少地质聚合物的凝固时间。相关结果表明，适量的纳米SiO2可以使粉煤灰基地质聚合物的微观结构更致密，并产生更高的机械强度。本研究基于地质聚合机理，总结了纳米SiO2对粉煤灰基地质聚合物的抗压强度、微观结构、硬化性能、剪切粘合强度、耐久性和实际应用等性能的影响。