Micromechanical model and performance-driven design strategy for textile reinforced engineered cementitious composite (TR-ECC)

Textile reinforced engineered cementitious composite (TR-ECC) is a cementitious composite reinforced with continuous textiles and short random fibers, characterized by high tensile strength and strain capacity due to the successive formation of multiple fine cracks. Various tensile failure modes of TR-ECC have been extensively observed in experimental studies, while clear classification of these failure modes and their underlying mechanisms are to be explored. In this study, the novel established numerical model explains the causes of different tensile failure modes of TR-ECC based on the physical interactions among fibers, textiles, and the matrix. In the model, the tensile behavior of TR-ECC was innovatively simulated through a displacement-controlled loading method, while the stress field in different components was analyzed considering five phases: textiles, short fibers, matrix, textile/matrix interface, and fiber/matrix interface. With the proposed model, two distinct tensile failure modes (modes I and II) were identified. Simulated TR-ECC stress-strain curves (OP-I and OP-II) of both failure modes were acquired with adjustments of several key micro-properties on the same base curve under the guidance of the proposed model. OP-I achieved a tensile strength exceeding 9.5 MPa and maintained a strain capacity above 2 % due to secondary hardening after textile rupture, while OP-II exhibited stable multiple cracking with a lower peak strength of 7.2 MPa but a higher strain capacity exceeding 6 %. These two specific optimization strategies were proposed based on the model to address different material performance requirements, providing a framework for performance-driven design of TR-ECC to ensure optimal mechanical performance and durability.