Abstract In this study, an agricultural waste-rice husk ash (RHA) is proposed to substitute fly ash in high strength, high ductility engineered cementitious composites (ECC). The experimental results showed that the substitution of fly ash by RHA accelerated hydration process, promoted pozzolanic reaction, and refined pore distribution in ECC matrix, thereby increased compressive strength of ECC mixtures significantly from 82 MPa to 108 MPa. On the other hand, tensile properties of ECC mixtures were improved with addition of RHA, except ECC mixture with substitute ratio of 50% showed a slight reduction in strain capacity yet exhibited highest strength. At micro-scale, incorporating RHA into ECC reduced the theoretical complementary energy (Jb′) as a result of enhanced fiber/matrix interface, meanwhile, lowered crack tip toughness (Jtip) in ECC matrix which mainly due to the evidently increased modulus of ECC; subsequently lead to the increment of pseudo strain-hardening PSH (=Jb′/Jtip) index, and thus ductility.

中文翻译：

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稻壳灰替代粉煤灰的环保型高强度、高延性工程水泥基复合材料（ECC）

摘要 在这项研究中，提出了一种农业废稻壳灰 (RHA) 来替代粉煤灰在高强度、高延展性工程水泥基复合材料 (ECC) 中的应用。实验结果表明，RHA 替代粉煤灰加速了水化过程，促进了火山灰反应，细化了 ECC 基体中的孔隙分布，从而使 ECC 混合物的抗压强度从 82 MPa 显着提高到 108 MPa。另一方面，加入 RHA 后，ECC 混合物的拉伸性能得到改善，但替代比例为 50% 的 ECC 混合物的应变能力略有降低，但强度却最高。在微观尺度上，由于增强的纤维/基质界面，将 RHA 纳入 ECC 降低了理论互补能量（Jb'），同时，ECC基体裂纹尖端韧性（Jtip）降低，这主要是由于ECC模量明显增加；随后导致伪应变硬化 PSH (=Jb'/Jtip) 指数增加，从而导致延展性增加。