بررسی آزمایشگاهی تاثیر نانوسیلیس بر خصوصیات مکانیکی و دوام بتن خودتراکم در مواجهه با محیط های کلریدی

بتن خود تراکم به دلیل ویژگی های برجسته اش مانند خواص مکانیکی و دوام برتر شناخته شده است. خوردگی میلگرد در اثر نفوذ یون های کلرید در عناصر بتن مسلح از اهمیت ویژه ای برخوردار است. بنابراین این موضوع در بتن خود تراکم باید بررسی شود. از مواد پوزولانی می توان در بتن خود تراکم برای افزایش مقاومت بتن در برابر نفوذ یون کلر استفاده کرد. در این تحقیق اثرات مواد پوزولانی شامل میکرو سیلیس، نانو سیلیس، خاکستر بادی، خاکستر پوسته برنج و همچنین پودر سنگ آهک بر خصوصیات مکانیکی و دوام بتن خود متراکم قرار داده شده در محیط کلرید بررسی شده است. نتایج نشان می دهد که نانو سیلیس ویژگی های مکانیکی و دوام بتن خود متراکم را افزایش می دهد. علاوه بر این، بتن خود تراکم حاوی ترکیبی از نانو سیلیس و مواد پوزولانی دارای خواص بهتری نسبت به نمونه حاوی نانو سیلیس است.

experimental study of the effect of nano-silica on the mechanical properties and durability of self-compacting concrete placed in chloride environments

in recent years, nanotechnology has attracted the attention of many scientists and researchers, which is due to the use of nanoscale particles and their unique physical and chemical properties. on the other hand, cement is a material that binds concrete components together and is widely used in construction projects. as a result, the use of nanomaterials in the production of cement and concrete can improve civil infrastructures, because the lifespan of structures and mechanical resistance are determined by infrastructures and mass transfer on a nano scale. on the other hand, the concrete industry also takes into account its needs in terms of strength, resistance, high efficiency and durability, as well as the problem of corrosion of reinforcements in concrete due to the penetration of chlorine ions, which is one of the biggest challenges of stability and durability in reinforced concrete structures is one of the important users of nanostructure materials. self-compacting concrete (scc) is known for its outstanding characteristics such as superior mechanical and durability properties. corrosion of rebar due to penetration of chloride ions in the reinforced concrete elements is of particular importance. therefore, this issue in the scc must be investigated. pozzolanic materials could be used in the scc to increase the resistance of concrete against chlorine ion penetration. in this research, effects of pozzolanic materials including micro silica, nano silica, fly ash, rice husk ash, as well as limestone powder on the mechanical and durability characteristics of self-compacting concrete placed in chloride environment have been studied. to check the performance of the above mixtures, properties such as compressive and bending strength, water absorption, expansion and contraction value, electrochemical corrosion potential, ultrasonic, chlorine ion penetration and electrical resistance of the samples located in the environmental conditions of ordinary water and destructive saline with 3% salt it has been evaluated for 180 days. based on the results obtained from research and experiments, nanosilica improves the mechanical properties of self-compacting concrete, such as durability and compressive and bending resistance against corrosive environments. it was observed in designs containing nanosilica and pozzolanic materials, the said samples have better properties than samples with nanosilica alone. in the meantime, the design containing nanosilica and microsilica showed the best resistance results in addition to the durability of concrete compared to other samples in the conditions of a destructive salt environment, and among the pozzolans that are used in this research, rice paddy husk ash is the most sensitive. against contraction, which is very important. the use of nanomaterials in the production of cement and concrete can improve civil infrastructures, because the lifespan of structures and mechanical resistance are determined by infrastructures and mass transfer at the nanoscale. on the other hand, the concrete industry also considers its needs in terms of strength, resistance, durability and high efficiency, as well as the problem of corrosion of reinforcements in concrete due to the penetration of chlorine ions, which is one of the biggest challenges of durability and stability in reinforced concrete structures, one of the most important users is the structure of nano materials. the results show that nano-silica increases the mechanical and durability characteristics of self-compacting concrete. moreover, the scc containing combination of nano-silica and pozzolanic materials has better properties than the one containing nano-silica.