Abstract
Based on theoretical calculations and laboratory tests, this article studies the effect of nano-materials and fiber materials on the impermeability and chemical resistance of concrete, analyzes the mechanism of impermeability and corrosion resistance of concrete from macroscopic and microscopic aspects respectively and establishes the relationship between the impermeability and corrosion resistance of nano-concrete with its pore structure, compressive strength and flexural strength. According to the research results, the fiber material has not improved the pore structure inside the concrete, but much worse degradation appears in the interior of concrete due to the agglomeration caused by uneven mixing. With the addition of nano-materials (SiO2 and TiO2), the total pore volume, the most probable pore diameter and other pore structure parameters of the concrete all show a decrease in the total number of harmful pores (pore diameter >50 nm) and an increase in the number of harmless pores (pore diameter <50 nm). The concrete with 1% of TiO2 has the best improving effect on concrete pore structure, but if too much nano-material is incorporated, the pore structure inside the concrete will be worse; suggesting that proper amount of nano-materials can effectively improve the pore structure and pore distribution in concrete. The incorporation of nano-materials can greatly improve the resistance to chloride ion corrosion of concrete. And the greater the compressive and flexural strength of concrete is, the smaller the chloride diffusion coefficient will be. In general, chloride ion diffusion coefficient is in a clear linear relationship with these two. Thus compressive strength and flexural strength of concrete can be used to judge the chloride ion diffusion resistance of concrete. The pore structure distribution of concrete is proportional to its chloride ion corrosion resistance.
