高掺量硅灰石纤维对偏高岭土基地聚物性能和微结构的影响

Effect of high wollastonite fiber incorporation on metakaolin base geopolymers'properties and microstructure

为了研究高添加量的硅灰石纤维对偏高岭土-矿渣地聚物力学性能及开裂特性的影响,以硅灰石纤维替代质量分数(最高40wt%)为实验参数,制备了硅灰石/偏高岭土-矿渣地聚物,评估了与硅灰石含量有关的性能(力学强度、孔隙率和裂纹),并研究了硅灰石纤维对地聚物微结构的影响。结果表明:硅灰石纤维的加入对处于干燥环境下的地聚物抑制开裂行为有积极作用,且在替代量为40wt%以内是持续改善的;同时也观察到硅灰石纤维的加入对地聚物力学性能也有积极影响,其中硅灰石纤维替代量为20wt%的地聚物28天强度达到70.2 MPa,较偏高岭土基地聚物样品抗压强度增长了36%,但继续增加硅灰石纤维会导致地聚物抗压强度的降低;此外沸石相在复合物中被检测到,硅灰石的添加有利于沸石相的发展。

In order to study the effect of high addition of wollastonite fiber on the mechanical properties and cracking characteristics of metakaolin/slag geopolymer,wollastonite-metakaolin-slag geopolymer was prepared with the substitution mass fraction of wollastonite fiber(up to 40wt%)as the experimental parameter.The properties related to the content of wollastonite(mechanical strength,porosity and crack)were evaluated,and the effect of wollastonite fiber on the microstructure of geopolymer was studied.The results show that the addition of wollastonite fiber has a positive effect on inhibiting the cracking behavior of the geopolymer in dry environment,and it is continuously improved when the substitution amount is less than 40wt%.At the same time,it is also observed that the addition of wollastonite fiber has a positive effect on the mechanical properties of the geopolymer.The 28 days strength of the geopolymer with the substitution amount of wollastonite fiber of 20wt%reaches 70.2 MPa,which is 36%higher than the original compressive strength of metakaolin-based geopolymer.However,the continuous increase of wollastonite fiber will lead to the decrease of the compressive strength of the geopolymer.In addition,zeolite was detected in the composite,and the addition of wollastonite was beneficial to the development of zeolite phase.