Engineered Cementitious Composites (ECC) has demonstrated superior mechanical and durability performance than conventional concrete. In the micromechanical reinforcing system of ECC, fiber plays a pivotal role in establishing the ultrahigh tensile ductility and autogenous crack width control. This article reviews the state-of-the-art of discontinuous micro-fibers as intrinsic reinforcement of ECC regarding technical performance as well as environmental and economic impacts. Mechanical properties of ECC made with different micro-fibers, man-made or natural, and their embodied energy, emissions and material cost, are comprehensively surveyed. Further, studies on fiber hybridization are discussed regarding the combination of different fiber types to form synergetic reinforcements that mitigate total material cost, and potentially enhance the composite performance. Recommendations on fiber selections are highlighted and directions for future research are suggested.

工程水泥复合材料（ECC）已显示出比常规混凝土优越的机械性能和耐久性能。在ECC的微机械增强系统中，纤维在建立超高拉伸延展性和自生裂纹宽度控制方面起着关键作用。本文就技术性能以及对环境和经济的影响，综述了不连续微纤维作为ECC的内在增强的最新技术。对由人造或天然的不同微纤维制成的ECC的机械性能及其所体现的能量，排放量和材料成本进行了全面调查。此外，还讨论了有关纤维杂交的研究，涉及不同纤维类型的组合以形成协同增强材料，从而降低了总体材料成本，并有可能提高复合材料的性能。突出了有关纤维选择的建议，并提出了未来研究的方向。