开裂龄期对超高韧性纯粉煤灰基地聚合物自愈合性能的影响

Effect of Cracking Ages on Self-Healing of Pure Fly Ash-Based Engineered Geopolymer Composite

结合裂缝特征、拉伸性能及吸水性能多层面评价不同开裂龄期(3、7、14 d和28 d)对超高韧性纯粉煤灰基地聚合物(FA-EGC)自愈合性能的影响,同时采用红外光谱、X射线衍射、扫描电镜-能谱分析对FA-EGC裂缝自愈合产物组成及形貌进行了研究。结果表明:开裂龄期为7 d的FA-EGC试样的自愈合效果最好,其裂缝宽度减小幅度最大、极限强度恢复效果较好、平均吸水率下降得最多,经过28 d自愈合后,裂缝宽度从42μm减小至15μm,平均吸水率下降了29.5%。FA-EGC的自愈合产物为持续的地聚合反应生成的地聚合物凝胶以及CaCO_(3)。

The effect of cracking ages(i.e., 3, 7, 14 d and 28 d) on the self-healing of pure fly ash-based engineered geopolymer composite(FA-EGC) was evaluated by crack characteristics, tensile properties and water absorption. The components and microstructure of self-healing products of FA-EGC were investigated by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. The results show that there is an optimum self-healing effect of FA-EGC samples when cracking age is 7 d, a better recovery of ultimate tensile strength and a reduction in average water absorption rate can be obtained at the maximum decrease in crack width. The self-healing products of FA-EGC are the geopolymer gel generated by ongoing geopolymerization reaction and CaCO_(3).