The aim of this study was to investigate the freeze-thaw resistance of 3D-printed geopolymer mortars containing nano zinc oxide (nano-ZnO). Metakaolin (MK) and fly ash (FA) were selected as binders in the geopolymer mortar. The mixes containing 0 %, 0.25 %, 0.5 %, and 0.75 % nano-ZnO were prepared. The viscosity, setting time, buildability, and flow experiments were made to determine the fresh properties of the samples. Then, 40 × 40 × 160 mm samples for hardened properties were produced using the 3D printer, and they were cured at 20 ± 2 °C for 28 days. In this study, the 3D-printed geopolymer mortars were subjected to freeze-thaw cycles according to TS EN 15177 standard. Finally, ultrasonic pulse velocity (UPV), the weight change, flexural strength, and compressive strength of 3D-printed geopolymer mortar samples exposed to freeze-thaw cycles were determined. Also, the microstructure of 3D-printed geopolymer mortar samples was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. This study found that the 3D-printed geopolymer mortars containing 5 % nano-ZnO had the highest resistance to freeze-thaw, with a compressive strength retention rate of 95.72 %. Thus, this study showed that the 3D-printed geopolymer mortars containing ZnO were resistant to freeze-thaw.

中文翻译：

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纳米氧化锌对3D打印地聚合物砂浆抗冻融性能的影响


本研究的目的是研究含有纳米氧化锌 (nano-ZnO) 的 3D 打印地质聚合物砂浆的抗冻融性。选择偏高岭土（MK）和粉煤灰（FA）作为地质聚合物砂浆的粘合剂。制备含有 0%、0.25%、0.5% 和 0.75% 纳米 ZnO 的混合物。进行粘度、凝固时间、可施工性和流动性实验以确定样品的新鲜特性。然后，使用3D打印机生产40×40×160毫米的硬化性能样品，并在20±2℃下固化28天。在这项研究中，根据 TS EN 15177 标准对 3D 打印地质聚合物砂浆进行冻融循环。最后，测定了暴露于冻融循环的 3D 打印地质聚合物砂浆样品的超声波脉冲速度 (UPV)、重量变化、弯曲强度和压缩强度。此外，还使用 ​​X 射线衍射 (XRD)、扫描电子显微镜 (SEM) 和能量色散 X 射线 (EDX) 分析对 3D 打印地质聚合物砂浆样品的微观结构进行了分析。研究发现，含有5%纳米ZnO的3D打印地聚合物砂浆具有最高的抗冻融能力，抗压强度保留率为95.72%。因此，这项研究表明，含有ZnO的3D打印地质聚合物砂浆具有抗冻融能力。