碱激发粉煤灰-硅灰基地质聚合物的性能及表征

Properties and Characterization of Alkali-activated Fly Ash-Silica Fume Based Geopolymers

以粉煤灰(FA)和硅灰(SF)为主要原料制备碱激发地质聚合物胶凝材料,运用XRD、SEM、EDS及FTIR等测试手段研究了SF与FA的质量比(SF/FA)及不同碱激发剂(NaOH和KOH)对粉煤灰-硅灰基地质聚合物砂浆力学性能及组织结构的影响。研究结果表明,随着SF/FA的增大,碱激发粉煤灰-硅灰基地质聚合物的抗压强度和抗折强度逐渐增大,最高可分别达到23.89 MPa和6.60 MPa,NaOH的激发效果强于KOH。碱激发粉煤灰-硅灰基地质聚合物结构中新生成了菱沸石相和无定形N-A-S-H凝胶相,FA和SF反应不完全,结构中仍存在未反应的FA颗粒及SF颗粒。FTIR结果表明N-A-S-H相的存在,随着SF/FA的增大,碱激发粉煤灰-硅灰基地质聚合物中[AlO6]9-八面体和[AlO4]5-四面体发生了结构重组,配位状态进一步完善,且T-O-Si(T=Al,Si)发生了聚合,致使地质聚合物强度逐渐增大。

The alkali-activated geopolymer materials were prepared using fly ash(FA)and silica fume(SF)as the main raw materials.The effects of SF/FA mixture ratio and different alkali activators(NaOH and KOH)on the mechanical properties and microstructure of fly ash-silica fume based geopolymers were studied.The results show that the compressive strength and flexural strength of the geopolymers gradually increase with the increase of SF/FA mixture ratio,and the maximum strength reach 23.89 MPa and 6.60 MPa,respectively.The activating effect of NaOH is more effective than that of KOH.The mineral phases existed in the structures of geopolymers form rhombozeolite phases and the amorphous N-A-S-H gel phase newly,the unactivated SF and FA particles are also found in the geopolymers.FTIR results show that[AlO6]9-octahedron and[AlO4]5-tetrahedron are reorganized,the state of[AlO6]9-octahedron and[AlO4]5-tetrahedron is further strengthened,in addition,the T-O-Si(T=Al,Si)structures are polymerized with the increase of SF/FA ratio,which increases the strength of the geopolymers.