This study introduces a novel method for incorporating artificial flaws in Engineered Cementitious Composite (ECC) by applying carbon nanotube (CNT) polymer nanocomposite coatings, which has a porous microstructure, to aggregates. In comparison with the control ECC, the implementation of coated aggregates can improve the crack number and the strain capacity of ECC by 268 % and 83.7 %, respectively, while only incurring a 14.1 % decrease in compressive strength. Furthermore, increasing the sand-to-binder (s/b) ratio from 0.36 to 0.75 can improve the strain capacity of ECC by 213.1 %, with a reduction of compressive strength by 22.6 %. The underlying mechanisms were investigated both experimentally and theoretically, which revealed that the reduced spacing between artificial flaws significantly increases the stress concentration factor, thereby facilitating crack initiation and propagation. The simplicity, cost-effectiveness, and general applicability of this coating technique offer a valuable method for enhancing the performance of ECC, which could substantially advance its practical applications.

中文翻译：

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通过骨料的纳米复合涂层在工程水泥基复合材料 （ECC） 中引入人工缺陷：一种新的方法和机制


本研究介绍了一种通过将具有多孔微观结构的碳纳米管 （CNT） 聚合物纳米复合涂层应用于骨料，在工程水泥基复合材料 （ECC） 中加入人工缺陷的新方法。与控制 ECC 相比，涂覆骨料的实施可以将 ECC 的裂纹数和应变能力分别提高 268 % 和 83.7 %，而抗压强度仅降低 14.1 %。此外，将砂与粘合剂 （s/b） 的比率从 0.36 提高到 0.75 可以将 ECC 的应变能力提高 213.1 %，同时将抗压强度降低 22.6 %。从实验和理论上研究了潜在的机制，结果表明，人工缺陷之间间距的减小显著增加了应力集中因子，从而促进了裂纹的萌生和扩展。这种涂层技术的简单性、成本效益和普遍适用性为提高 ECC 的性能提供了一种有价值的方法，这可以大大促进其实际应用。