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Highlights • 5% TiO 2 in ECC saturates air-purification ability while preserving tensile properties. • The optimized TiO 2 -doped ECC sustains a tensile strain capacity of 4.0%. • Alterations in tensile properties of ECC by TiO 2 are understood by micromechanics. • Both site effect and dilution effect are operative in ECC when TiO 2 is added. Abstract 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. [ABSTRACT FROM AUTHOR]

Using Martian resource to construct a site on Mars is a superior choice to instead of transporting all the construction materials from Earth to the Mas with incredibly high cost. This study proposes a developed Martian concrete composed of sulfur and magnetite, heated by microwave to meet the energy-poor environment on Mars. A lattice Boltzmann model is developed to determine the optimal microwave power and heating time for Martian concrete casting. The compressive strength and microstructure of Martian concrete casted by microwave are measured by test. Finally, a 3D printed device is conceived to prepare Martian concrete and the four-layered specimen is casted to simulate the 3D print process. The results indicate that the compressive strength of Martian concrete casted by microwave can reach 1.78 kgf/mm2 (17.44 MPa) on earth, which is corresponding to 4.62 kgf/mm2 on Mars. Since the heating rate of magnetite under microwave is very high, if possible, the low microwave power and long heating time should be chosen to reduce the temperature gradient in matrix and reduce the possibility of sulfur matrix boiling. In addition, the strength of four-layered (simulated 3D printed) Martian concrete can reach 1.21 kgf/mm2 (11.86 MPa) on earth, which is corresponding to 3.15 kgf/mm2 on Mars. [Display omitted] [ABSTRACT FROM AUTHOR]