Micro silica is a tiny particle material made from ferrosilicon and silicon metal alloys. Silica fume powder is a fine-sized powder that is 100 times more minute than cement and fly ash. The silica fume is grey in color with particles of very tiny size.
It is useful to boost the quality of concrete. Silica fumes in concrete are very important for building better quality and long-lasting structures. Micro silica is also beneficial for flexural, bonding, and built compressive strength in the concrete.
Micro silica also helps in avoiding corrosion and improves the quality of concrete. Thus, silica fumes are used multiple times in the construction industry.
What is silica fume?
Knowing about silica fume uses and its properties is very important as it has both advantages and disadvantages. The labor or the supervisor at the construction site should be aware of all its benefits and properties as the use of silica fumes in concrete should be done in an appropriate manner.
The use of silica fumes in cement concrete should be of an appropriate quantity as excessive use may degrade the quality of concrete.
Silica fumes look like ordinary Portland cement or fly ash. Silica fume is a non-crystalline material with particles 100 times smaller than cement. The silica fume is categorized into two categories such as un-densified silica fume and dense silica fume. The silica fume properties and density for both the un-densified and densified materials are different.
The un-densified silica fume has a density of 250-350 kg/m3 while the dense silica fume has a density of 550-700 Kg/m3. For enhancing or modifying the properties of concrete silica fumes is a recommended material to be used in concrete to avoid rusting metal inside the structures and to increase the strength of the structure. To build Long lasting structures silica fume is a beneficial material.
Why is silica fume an important material?
Silica fume is a material made up of very minute particles that mix well with concrete and help fill the pores inside the concrete. Silica fumes can achieve good compressive strength for the concrete and help in maintaining better corrosion resistance to the steel structure of the concrete.
Rusting of steel inside the concrete leads to degradation of structures and lowers the life of the structure. Thus, building excellent quality structures using silica fumes is beneficial. The silica fume in concrete helps in the permeability of the mixture and improves the durability of the structure.
Silica fume has one of the better advantages in that it is suitable for use in any kind of cement. There are no limitations for the reactions of any category of cement. The silica fume has its application in refractories as well to gain better strength and high-temperature performance which has applications in rubber and glass industries.
How is silica fume used in concrete?
There are multiple chemical reactions involved in the silica fume and knowing them is necessary as the wrong use of the material may lead to serious problems with the structure.
There are two types of chemical compounds formed once water silica fume is added to the cement concrete after mixing water into it. The calcium silicate hydrate is a crystalline compound responsible for material strength. Calcium hydroxide is a by-product that helps in filling the gaps and pores within the concrete.
Below are the important advantages of micro silica in concrete:
Silica fumes are used across the world for construction purposes as the material helps in gaining better strength, helps fill the pores of the concrete, and helps in avoiding rusting steel inside the structure.
- Stable physical and chemical properties: The silica has very neutral properties, both chemical and physical properties.
- Increased thermal conductivity: Silica fume increases thermal conductivity, improves flame retardancy, and changes the adhesive velocity.
- Good absorption capacity: The silica fume has got good absorption capacity and good infiltration in the retardation process.
- Reduced precipitation and stratification: As the particles of silica fume are very minute in size it can effectively reduce precipitation and stratification.
- Improved strength: Higher strength of the concrete can be achieved with the help of silica fumes. The minute particles of the silica fume help fill the tiny particles of the concrete to fill the pores which improves the strength of the concrete. The use of silica fumes in concrete can help improve the resistance, tensile strength, and compressive strength.
- Improved insulation: Silica fume possesses stable physical and chemical properties that ensure good insulation of the curing material.
- Improved corrosion resistance: The corrosion of steel poses a high chance of damage to the structure. The improved corrosion resistance is achieved through silica fume as it protects the structure from getting rusted. Silica fume helps in improved cavitation and corrosion resistance by up to 16 times higher.
- Reduced induction period: Early strength can be achieved with the help of silica fume, and it also shortens the induction period.
- Prevention of cracks: Silica fume can reduce the peak temperature achieved during the curing reaction. Silica fume reduces the shrinkage rate of the concrete thus reducing internal stress and avoiding the cracks to be formed in the structures. The binding of the concrete increases which leads to the prevention of cracks in the structure. Durable and strong structures can be built with the addition of silica fumes inside the concrete.
Disadvantages of silica fume:
- Difficulty of construction: The workability of the concrete is necessary during construction. The contractor and the laborer should ensure the use of silica fumes should be in appropriate quantity. Excessive mixing of silica fumes can lead to concrete becoming more compacted and thus using the concrete for plastering may become difficult. Excessive use of silica fumes may also lead to poor concrete quality, smoothness of the concrete, and uniformity of the surface.
- Dry shrinkage: The shrinkage rate of silica fume is relatively higher, especially during the early dry shrinkage. The moisture inside the concrete may be reduced due to excessive use of silica fumes. Dry shrinkage may affect the overall strength of the product.
- Temperature cracks: While the silica fume gains early strength in the concrete the corresponding hydration dissipates quickly which leads to an increase in temperature of the concrete. Increased temperature of the concrete leads to wider cracks, thus affecting the quality of the structure.
- High prices: The prices of silica fumes are quite high compared to cement concrete or fly ash. Though the silica fume is a bit costlier, the addition of this material in concrete can help in reduced maintenance of the structure in the long run.
Sakshi Chem Sciences Pvt Ltd is a leading manufacturer of construction chemicals. Thus, the micro silica material is named Fumecrete 90 by Sakshi Chem Sciences Pvt Ltd which is an excellent product and recommended to our clients for getting the best results in construction. Due to its larger benefits and lower disadvantages, the silica fume is a great quality product.
Conclusion:
Micro silica is amongst the best quality products with multiple advantages like achieving better strength and providing protection from corrosion of steel inside the structure. Micro silica acts as a binding particle for the concrete which helps in reducing the pores of the concrete. As the particles of silica fume are very minute it mixes easily in concrete.
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