Nano-silica, due to its extremely small particle size and high specific surface area, is recognized as a very effective additive in the production of ultra-lightweight concrete. This material, by making changes in the concrete structure, significantly improves its mechanical properties, durability, and some other features.
Mechanism of Nano-Silica Function in Concrete
- Filling Voids: Nano-silica particles, due to their very small size, are able to fill microscopic voids in concrete. This reduces porosity and increases the density of concrete.
- Formation of C-S-H Gel: Nano-silica reacts with calcium hydroxide present in concrete to form C-S-H (Calcium-Silicate-Hydrate) gel. This gel has very high strength and good adhesion to other concrete components, improving the mechanical properties of concrete.
- Increased Specific Surface Area: The high specific surface area of nano-silica increases the contact surface area between cement particles and water, and as a result, the rate of cement hydration increases.
- More Uniform Particle Distribution: Due to its very small size, nano-silica is easily dispersed in the concrete mixture and creates a more uniform distribution of particles. This improves the mechanical properties and durability of concrete.
Properties and Applications of Concrete Containing Nano-Silica
- Increased Compressive and Tensile Strength: Concrete containing nano-silica has higher compressive and tensile strength compared to ordinary concrete.
- Reduced Permeability: Nano-silica, by reducing concrete porosity, reduces its permeability to water and harmful ions. This increases the durability of concrete against environmental factors such as freezing and chloride ion penetration.
- Increased Durability: Concrete containing nano-silica has higher durability against abrasion, corrosion, and environmental factors.
- Reduced Weight: Using nano-silica, lighter concrete can be produced, which is used in the construction of tall buildings and bridges.
- Self-healing: Some research shows that concrete containing nano-silica has self-healing properties and can automatically repair small cracks.
- Improved Thermal Properties: Nano-silica can improve the thermal properties of concrete, such as fire resistance and thermal insulation.
Applications of Ultra-Lightweight Concrete Containing Nano-Silica
- Construction: In the construction of load-bearing walls, roofs, floors, and other structural components of buildings
- Construction of Bridges and Tall Structures: Due to its low weight and high strength
- Automotive Industry: In the production of lightweight vehicle components
- Aerospace Industry: In the production of lightweight and resistant components
- Energy Industry: In the production of wind turbines and solar panels
In summary, nano-silica as a very efficient additive in the production of ultra-lightweight concrete, improves the mechanical properties, durability, and other features of concrete. This material has a wide range of applications in various industries including construction, automotive, and energy.