Research progress on the mechanical properties of high-strength high-ductility ECC: effects of matrix, fibers, and interface

High-strength high-ductility engineered cementitious composites (HSHD-ECC) have attracted extensive attention in the field of civil engineering due to their outstanding mechanical properties. This paper reviews recent research progress on HSHD-ECC and discusses the mechanisms by which the matrix, fibers, and fiber-matrix interface influence its static and dynamic mechanical properties, thereby elucidating the essential principles for achieving the dual objectives of high strength and high ductility. First, based on the theory of dense particle packing, the strengthening effects of inert and reactive supplementary cementitious materials as well as alternative aggregates on the matrix are summarized. Second, the influence mechanisms of fiber volume fraction, aspect ratio, and fiber type on the mechanical properties of HSHD-ECC are systematically analyzed, and corresponding reference design ranges are proposed for different mixing modes: The total volume fraction of hybrid fibers is generally maintained 1.5%–2.5%. PE fibers is designed to be 1%–1.5%, while ST fibers is limited below 1%. Finally, considering the effects of different matrix components and fiber parameters on fiber pull-out behavior, the interfacial characteristics are analyzed in combination with crack-bridging prediction models. The results of this review provide useful references for the multi-performance optimization design of HSHD-ECC.