Multiscale investigation of tensile properties of a TiO ₂ -doped Engineered Cementitious Composite

Engineered Cementitious Composites (ECC) provides a unique platform to develop high-performance and multifunctional construction materials with strain-hardening properties and exceptional crack control capability. ECC incorporating titanium dioxide (TiO ₂ ) nanoparticles has intrinsically embodied photocatalytic properties, such as air-purifying functionality. However, there remains a lack of fundamental knowledge on how the presence of TiO ₂ nanoparticles affects fiber/matrix interface and macro tensile properties of ECC. There is a need to establish a holistic understanding of the role of TiO ₂ nanoparticles in ECC at multiple scales. To this end, this study experimentally investigates the effect of TiO ₂ content (up to 15% of binder) on the fiber/matrix interface and on the tensile properties of ECC. A micromechanical model is used to link the multiscale material properties and interpret the test data of the TiO ₂ -doped ECC. Results show that changes in the macroscopic tensile properties as a result of TiO ₂ addition can be traced back to the matrix and fiber/matrix interface properties. The research findings provide insights into the underlying mechanisms of tensile property modifications by TiO ₂ nanoparticles, as well as establishing a reference for the design of photocatalytic ECC for balanced functional and mechanical properties.