Optimal slag content for geopolymer composites under freeze-thaw cycles with different freezing temperatures

Improving the freeze-thaw resistance of geopolymers is of great significance to ensure their durability in cold regions. This study presents an experimental investigation of optimal slag content for geopolymer composites under freeze-thaw cycles with different freezing temperatures. Firstly, five kinds of geopolymer composites with 10.0%, 20.0%, 30.0%, 40.0%, and 50.0% slag contents and 1.0% fiber content were prepared. Freeze-thaw cycle tests at −1.0 ℃, −20.0 ℃, and −40.0 ℃ were carried out for these geopolymer composites and their physical and mechanical properties after the freeze-thaw cycle were tested. The results show that the porosity of the geopolymer composites decreases as the slag content increases. Their mass loss ratio and strength loss ratio increase gradually as the freezing temperature decreases. The mass loss ratio and strength loss ratio of geopolymer composites after freeze-thaw cycles all decrease as the slag content increases. Considering the physical and mechanical properties of geopolymers after freeze-thaw cycles, the optimal slag contents are 40.0% and 50.0%. 目的 提高地聚物的抗冻融循环性能对确保地聚物在寒区中的耐久性具有重要意义。本文旨在研究冻结温度对矿渣改性的偏高岭土基地聚物物理和力学性能的影响,以期为地聚物在寒区中的实际应用和耐久性评估提供参考。 创新点 提出了冻融循环条件下地聚物复合材料的最佳矿渣含量;2. 发现矿渣的掺入可以抑制地聚物在寒冷环境中的开裂,提高地聚物复合材料的抗冻融性。 方法 制备不同矿渣的纤维增强聚合物并对其开展三种冻结温度的冻融循环试验;2. 分析不同矿渣的纤维增强聚合物的孔隙结构特性;3. 分析冻融循环后不同矿渣的纤维增强聚合物的物理力学性能;4. 提出冻融循环作用下地聚物复合材料的最佳矿渣含量。 结论 随着矿渣含量的增加,地聚物复合材料的孔隙率降低,且凝胶孔和过渡孔均逐渐减小;2. 冻融循环后,地聚物复合材料中的裂缝宽度和数量都随着矿渣含量的增加而减少,表明矿渣的掺入可以抑制地聚物在寒冷环境中的开裂;3. 矿渣的掺入可以显著降低地聚物复合材料在冻融循环后的质量损失率和强度损失率,进而提高地聚物复合材料的抗冻融性;4. 40.0%和50.0%矿渣含量的地聚物复合材料在冻融循环后仍能保持较高的力学性能。