محمد فلاح شیروانی

Under acid rain conditions, physical and chemical reactions occur in the concrete structure, which leads to a change in pH. As these reactions continue, the concrete begins to lose its mechanical strength, leading to cracking, weight loss, and eventual structural damage. Since the control of acid rain and its effects on the environment is inevitable in some cases, researchers have done many studies on this topic and have proposed solutions to eliminate or control its effects. One of the new solutions in this field is the use of nanoparticles. In recent years, studies have focused on silica nanoparticles, with the aim of using this material to further enhance the properties of concrete. The addition of nanosilica to concrete reduces the water permeability of the concrete as well as higher resistance to chemical attacks. In this paper, the mechanical properties and durability of nanosilica-containing concrete including weight loss, compressive strength, electrical resistance and water absorption under acidic conditions are investigated. By increasing nanosilica to concrete under normal conditions, the mechanical properties of concrete are improved, but according to the observed results, when the samples are placed in acidic conditions, the nanosilica in the samples reacts with acid and the performance of nanosilica improves the properties. The mechanical properties of the concrete deteriorate due to the mechanical replacement of the percentage of cement with nanosilica.

In the conditions of acid rain, chemical reactions occur in the concrete structure, which leads to a change in pH. When these reactions continue, concrete begins to lose its mechanical strength, which leads to cracking, weight loss, and finally the destruction of the structure. Since the control of acid rain and its effects on the surrounding environment is unavoidable in some cases, so far researchers have conducted many studies on this category and have provided solutions to eliminate or control its effects. One of the new solutions in this field is the use of nanoparticles. In recent years, studies have been focused on silica nanoparticles, with the aim of increasing the properties of concrete by using this material. Adding nano-silica to concrete in non-acidic (neutral) conditions reduces water permeability in concrete and also increases resistance against chemical attacks. In this article, the mechanical characteristics and durability of concrete containing nano-silica, including weight loss, compressive strength, electrical resistance, and water absorption rate under acidic conditions are investigated. According to the obtained results, with the increase of nano-silica in concrete, the mechanical properties and durability of concrete improve, but with the increase of water acidity, the durability and mechanical properties of concrete decrease.