硫酸盐侵蚀-干湿交替耦合作用下纤维增强地聚合物砂浆性能

Performance of Fiber-reinforced Geopolymer Mortar under Sulfate Corrosion and Drying-wetting Alternation Coupling

为探究纤维对地聚合物材料抗硫酸盐侵蚀性能的影响,对纤维增强偏高岭土-粉煤灰(MK-FA)基地聚合物砂浆经硫酸盐侵蚀-干湿交替耦合作用后的宏观形貌特征、微观结构特征、质量损失率及力学性能等进行了研究,探讨了纤维对MK-FA基地聚合物砂浆抗硫酸盐侵蚀性能的改善机理。结果表明:随硫酸盐侵蚀-干湿交替次数的增加,试件力学性能先上升而后趋于稳定,质量损失率先增大后减小,纤维可改善地聚合物砂浆的抗硫酸盐侵蚀性能;Na 2 SO 4溶液主要侵蚀试件表面,对内部结构没有明显损害;稳定致密的内部结构及纤维的桥接作用使纤维增强MK-FA基地聚合物砂浆具有优异的耐硫酸盐侵蚀性能,有利于维持试件力学性能和结构稳定性。

In order to explore the effect of fiber on the sulfate erosion resistance of geopolymeric materials,the fiber-reinforced metakaolin-fly ash(MK-FA)based geopolymer mortar was prepared from the main raw materials of metakaolin and fly ash.The appearance,microstructure,mass loss rate and mechanical properties of fiber-reinforced MK-FA based geopolymer mortar were explored after sulfate corrosion and drying-wetting alternation coupling,and the improvement mechanism of sulfate resistance of mortar by fibers was analyzed.The results show that with the increase of sulfate corrosion and drying-wetting alternation cycle times,the mechanical performance of specimens first increase and then tend to be stable,while the mass loss first increases and then decreases,fibers improve sulfate resistance of geopolymer mortar.The sodium sulfate solution mainly erodes the surface of the specimens,does not generate gypsum and ettringite,and has no obvious damage to the internal structure.Both stable and dense structures of samples and fiber-bridged matrix function make fiber-reinforced MK-FA based geopolymer mortar present excellent performance in resistance to sulfate attack,which is beneficial to maintain the mechanical properties and structural stability of specimens.