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Pure Silica Microsilica, also known simply as silica fume, is a high-performance supplementary cementitious material (SCM) that consists primarily of amorphous silica (SiO2) particles. Here’s its composition and uses:
Composition:
- Silicon Dioxide (SiO2): Pure Silica Microsilica is composed predominantly of silicon dioxide, typically ranging from 85% to 98% by weight. This silica is in the form of extremely fine particles, with a large surface area, and is highly reactive with calcium hydroxide (Ca(OH)2) produced during cement hydration.
Uses:
- High-Performance Concrete Production: Pure Silica Microsilica is extensively used as a key ingredient in the production of high-performance concrete. When added to concrete mixtures, it fills the voids between cement particles, leading to denser concrete with improved strength, durability, and resistance to various deleterious agents.
- Reducing Permeability: Addition of Pure Silica Microsilica to concrete mixtures helps in reducing the permeability of concrete, making it less susceptible to water penetration and chemical attacks. This property is particularly beneficial in structures exposed to harsh environments, such as marine structures and bridges.
- Enhancing Strength and Durability: Pure Silica Microsilica improves the compressive strength, flexural strength, and abrasion resistance of concrete. It promotes the formation of additional calcium silicate hydrate (C-S-H) gel, the primary binder in concrete, resulting in higher early-age and ultimate strengths, as well as enhanced resistance to chemical attacks and alkali-silica reaction (ASR).
- Infrastructure Projects: Pure Silica Microsilica finds extensive use in a wide range of infrastructure projects, including bridges, tunnels, highways, and dams, where high-performance concrete is essential for ensuring long-term structural integrity and durability.
- Shotcrete and Repair Materials: It is also utilized in shotcrete and repair mortars to enhance their mechanical properties and bond strength to substrates. This ensures more durable and long-lasting repairs for deteriorated concrete structures.
In summary, Pure Silica Microsilica is a valuable additive in concrete production, offering numerous benefits such as improved strength, durability, and resistance to various environmental and chemical attacks. Its widespread use contributes significantly to the development of high-performance and sustainable concrete structures in the construction industry.
