Li Erwang, Du Wei, Zhuang Ronghua, Ba Mingfang, Yuan Lianwang, Zhang Qian, Zhang Yuepin
School of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China.
Materials (Basel). 2022 May 18;15(10):3608. doi: 10.3390/ma15103608.
Cement-based materials are susceptible to internal cracks during service, leading to a reduction in their durability. Microcapsules can effectively self-repair cracks in cement-based materials. In this study, novel electromagnetic-induced rupture microcapsules (DWMs) were prepared by using the melt dispersion method with FeO nano-particles/polyethylene wax as the shell and epoxy resin as the repairing agent. The core fraction, compactness, particle size distribution, morphology, and chemical structure of DWMs were characterized. DWMs were subsequently incorporated into the mortar to measure the pore size distribution, compressive strength recovery, and maximum amplitudes of the pre-damaged mortar after self-repairing. DWMs were also evaluated for their ability to self-repair cracks on mortar surfaces. The results showed that the core fraction, remaining weight (30 days), and mean size of DWMs were 72.5%, 97.6 g, and 220 μm, respectively. SEM showed that the DWMs were regular spherical with a rough surface and could form a good bond with cement matrix. FTIR indicated that the epoxy resin was successfully encapsulated in the FeO nano-particles/polyethylene wax. After 15 days of self-repairing, the harmful pore ratio, compressive strength recovery, and maximum amplitude of the pre-damaged mortars were 48.97%, 91.9%, and 24.03 mV, respectively. The mortar with an initial crack width of 0.4-0.5 mm was self-repaired within 7 days. This indicated that the incorporation of DWMs can improve the self-repair ability of the mortar. This work is expected to provide new insights to address the mechanism of microcapsule rupture in self-repairing cement-based materials.
水泥基材料在使用过程中易产生内部裂缝，导致其耐久性降低。微胶囊可以有效地对水泥基材料中的裂缝进行自修复。在本研究中，采用熔体分散法，以FeO纳米颗粒/聚乙烯蜡为壳材、环氧树脂为修复剂，制备了新型电磁诱导破裂微胶囊（DWMs）。对DWMs的芯部占比、致密性、粒径分布、形态和化学结构进行了表征。随后将DWMs掺入砂浆中，以测量自修复后预损伤砂浆的孔径分布、抗压强度恢复情况和最大振幅。还评估了DWMs对砂浆表面裂缝的自修复能力。结果表明，DWMs的芯部占比、剩余重量（30天）和平均尺寸分别为72.5%、97.6 g和220μm。扫描电子显微镜（SEM）显示，DWMs呈规则球形，表面粗糙，能与水泥基体形成良好的粘结。傅里叶变换红外光谱（FTIR）表明，环氧树脂成功地封装在FeO纳米颗粒/聚乙烯蜡中。自修复15天后，预损伤砂浆的有害孔隙率、抗压强度恢复率和最大振幅分别为48.97%、91.9%和24.03 mV。初始裂缝宽度为0.4 - 0.5 mm的砂浆在7天内实现了自修复。这表明掺入DWMs可以提高砂浆的自修复能力。这项工作有望为解决自修复水泥基材料中微胶囊破裂的机理提供新的见解。
