Analyzing the Effects of Nano-Titanium Dioxide and Nano-Zinc Oxide Nanoparticles on the Mechanical and Durability Properties of Self-Cleaning Concrete.

The goal of this paper is to investigate the impact of nano-materials on the mechanical and electrochemical properties of self-cleaning concrete. Nano-titanium dioxide and nano-zinc oxide were used as additives for this purpose. Additionally, a comparative study on the effect of using these materials on the self-cleaning concrete's characteristics was conducted. The dosages of nano-titanium dioxide (nps-TiO2) and nano-zinc oxide (nps-ZnO) used were 0, 0.5, 1, 1.5, 2, and 2.5% and 0, 1, 2, and 3% of the weight of the cement, respectively. The results showed that the optimum compressive strength and the lowest corrosion rate were fulfilled at 2.5% of nps-TiO2 and 1% of nps-ZnO, and using 2.5% of nps-TiO2 achieved the highest improvement in the corrosion rate. However, 1% for nps-TiO2 mixtures and 1% for nps-ZnO mixtures were the best ratios for flexural strength. On the other hand, for the corrosion rate, the samples were tested at 2 and 6 months. When nps-TiO2 and nps-ZnO samples were compared to the control sample, 2.5% and 1% of nps-TiO2 and nps-ZnO, respectively, showed the largest improvement in resistance to corrosion. Also, the self-cleaning property of the samples containing nano-materials (nps-TiO2 and nps-ZnO) was tested. As the results illustrated, the self-cleaning property of the samples was increased over time due to photocatalytic degradation. Furthermore, the results of the photocatalytic tests showed that nps-TiO2 samples outperformed nps-ZnO samples overall.

Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC.

This investigation presents the influence of various types of nanoparticles on the performance of ultra high performance concrete (UHPC). Three nanoparticles from waste materials include nano-crushed glass, nano-metakaolin, nano-rice husk ash were prepared using the milling technique. In addition, nano-silica prepared using chemical method at the laboratory is implemented to compare the performance. Several UHPC mixes incorporating different dosages of nanoparticles up to 5% are prepared and tested. Mechanical properties, durability as well as the microstructure of UHPC mixes have been evaluated in order to study the influence of nanoparticles on the hardened characteristics of UHPC. The experimental results showed that early strength is increased by the incorporation of nanomaterials, as compared to the reference UHPC mix. The incorporation of 3% nano-rice husk ash produced the highest compressive strength at 91 day. Microstructural measurements using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), and Thermogravimetric Analysis (TGA) confirm the role of nanomaterials in densifying the microstructure, reducing calcium hydroxide content as well as producing more C-S-H, which improves the strength and reduces the absorption of UHPC. Nanoparticles prepared from waste materials by the milling technique are comparable to chemically prepared nanosilica in improving mechanical properties, refining the microstructure and reducing the absorption of UHPC.