纤维增强水泥基复合材料自愈合性能研究

Research on self-healing properties of fiber reinforced cementitious composites

从纤维增强水泥基复合材料配合比出发,研究了掺加粉煤灰、偏高岭土、硅灰、矿渣、磷渣等矿物掺合料后PVA纤维增强水泥基复合材料拉伸性能,并以强度恢复、裂缝变化为标准研究了在干湿循环养护条件下掺加不同掺合料时复合材料裂缝自愈合性能。结果表明:添加矿渣、硅灰与偏高岭土时复合材料表现出最佳的拉伸性能,峰值拉应变高达2.2%,并也表现出上佳的裂缝自愈合能力,开裂材料干湿循环养护28 d后的强度能达到预裂加载时强度的117%。初始裂缝宽度对裂缝自愈合起主导作用,小于50μm的裂缝基本都能愈合,而大于150μm的裂缝愈合效果不明显。

To study the self-healing properties of fiber reinforced cementitious composites （ECC）, fly ash, metakaolin, silica fume, slag and phosphorus slag were added with different mix proportion to the cement-based materials.Tensile tests were carried out to determine the tensile properties of ECC materials,then the self-healing behaviors of ECCs were evaluated on the basis of strength recovery and crack width reduction.The results show that a material with fly ash, silica fume, slag and metakaolin presents the greatest tensile property with an ultimate strain of 2.2%.In addition, it also shows the best self-healing behavior,the tensile strength of this self-healed material can reach 117% of its initial pre-loading tensile strength after a wet-dry cycle curing for 28 days.The initial crack width has a dominant influence on the self-healing ratio.Cracks under 50 μm can be heal completely, while those over 150 μm are not healed obviously.