摘要
在1%、2%及3%不同程度预加单轴直接拉伸应变破坏下,研究了3天、7天及28天龄期的高延性聚乙烯醇(PVA)纤维增强偏高岭土-粉煤灰基地聚合物(PVA/MK-FA EGC)在空气中和干湿循环条件下的裂缝分布及自愈合性能。结果表明:PVA/MK-FA EGC结合了传统高延性纤维增强水泥基复合材料(ECC)及地聚合物二者的优点,表现出了明显的多缝开裂特性和应变硬化行为。2～5mm的裂缝间距、小于25μm的最大残余裂缝宽度给裂缝的自愈合提供了更加有利的条件。带缝试件在不同环境中自愈合后,裂缝数量大大下降,极限拉伸应变可达3.8%以上,大部分试件的极限拉应变及最终应力均能超过对比试件,空气中的养护环境更加有利于PVA/MK-FA EGC材料的自愈合。裂缝内颗粒表面覆盖有凝胶状的地聚合产物,可能增强了体系中的纤维/基体界面,使力学性能恢复。
The crack distribution and self-healing characteristics of engineered geopolymer composites using metakaolin and fly ash（PVA/MK-FA EGC）at various pre-loadings of 1%,2% and 3% under air and wet/dry conditioning cycles were investigated at age of 3 days,7 days and 28 days.The results show that PVA/MK-FA EGC combines the advantages of traditional engineered cementitious composite（ECC）and geopolymer,exhibiting obvious multiple cracking pattern and a strain-hardening behavior.The crack spacing is in the range of 2-5 mm and the maximum residual crack width is below 25μm,which provide more favorable conditions for self-healing.After selfhealing under different environments,number of crack decreases significantly.The ultimate tensile strain can exceed3.8%,and both ultimate tensile strain and tensile strength capacity of the majority specimens at reloading are higher than the control specimens.Air conditioning can favor the self-healing of the PVA/MK-FA EGC materials.The surface of the particles in the crack is covered with geopolymeric gel,which may enhance the bond of fiber and matrix,resulting in the recovery of the mechanical properties.
作者
阚黎黎
段贝贝
闫涛
KAN Lili;DUAN Beibei;YAN Tao(School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China;School of Navel Architecture, Ocean ＆ Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2018年第10期2841-2850,共10页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(51508329)
