Evaluating the effects of titanium dioxide (TiO2) and carbon-nanofibers (CNF) as cement partial replacement on concrete properties

The objective of this study is to develop durability and mechanical characteristics of concrete mixtures by incorporating nano-engineering practices. The application of titanium dioxide (TiO 2 ) and carbon-nanofibers (CNF) in concrete have received strong consideration in recent years. However, the durability and mechanical properties of these kinds of concretes have not been evaluated thoroughly. To achieve this purpose, an experimental program was designed to assess the performance of TiO 2 and CNF singularly and simultaneously. The mechanical and durability-related characteristics of concrete containing TiO 2 and CNF have been investigated. These nanoparticles as a partial replacement of cement might develop the pore structure of concrete leading to improved durability and strength upgrading of the concrete. The slump flow test was carried out to evaluate the capabilities of TiO 2 and CNF in the slump retention. To evaluate abrasion resistance and wear-ability of samples, weight loss, and rut depths were measured, respectively. Also, the resistance to freezing/thawing, bulk electrical resistivity, and shrinkage test were performed to analyze the pore structure. Although TiO 2 and CNF would fill gel pores of the paste to improve pore structure, using too much weaken mechanical characteristics.