What is nano silica used for?
Nano silica is used in variety products ranging from cosmetic to construction materials. Most of the nanoparticles reported in literature exhibit various size, shape and orientation and therefore significantly differ in product development. These nanoparticles are either in colloidal form or agglomerated dry powder.
What is nano silica?
Nano-silica modified coating is applied on the surface of concrete, which can prevent the degree of carbonization of concrete. The reason is that the nano-SiO2 particles reduce the microscopic defects in the concrete and the damage to the polymer molecules caused by ultraviolet rays [1].
Is nano silica toxic?
Amorphous SiNPs have a higher cytotoxicity to macrophages than submicron-sized particles [42]. The toxicity of nano- and micron-sized silica particles (14 nm and 1–5 μm, respectively) was compared. Concentrations greater than 200 μg/ml are large enough to induce cytotoxic and genotoxic effects in RAW 264.7 cells [45].
How is nano silica made?
By reacting 1 kg of sulphuric acid 3M with 190 g of Olivine at 90°C in a stirred reactor 65 g of nano-silica is produced. Silica produced by olivine dissolution has very low particle size and high surface area in micropores.
What are the disadvantages of high silica cement?
disadvantages of silica fume in concrete
- Silica fume concrete is too viscous and difficult to apply.it is not easy to wipe the surface.
- Silica fume requires a high amount of water and needs to be used with a superplasticizer.
- The price of silica fume is relatively high compared to cement and fly ash.
What does nano stand for?
The term “nano” comes from ancient Greek and means “dwarf” (nános = dwarf). However, the nanosciences deal not with garden gnomes but with tiny nanostructures only a few nanometers in size (<100 nm). Used as a prefix, “nano” denotes 10-9, just as “kilo” denotes 103 and “milli” 10-3.
Is silica harmful to humans?
Breathing in very small (“respirable”) crystalline silica particles, causes multiple diseases, including silicosis, an incurable lung disease that leads to disability and death. Respirable crystalline silica also causes lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease.
Is silica safe on skin?
Silica in skincare is safe. Silica’s absorbing properties help you mattify your skin and keep the shine at bay. Less oil = less breakouts, too.
What are the advantages of using silica fume in concrete?
Advantages of Using Silica Fume
- High early compressive strength.
- High tensile flexural strength and modulus of elasticity.
- Very low permeability to chloride and water intrusion.
- Enhanced durability.
- Increased toughness.
- Increased abrasion resistance on decks, floors, overlays and marine structures.
What are the advantages of silica fume in concrete?
Advantages of silica fume in concrete: It does not contain crystalline water, does not participate in the curing reaction, and does not affect the reaction mechanism. (2) good infiltration for various kinds of resin, good adsorption performance, easy to mix, no agglomeration phenomenon.
What is nano a nickname for?
Nano is a short form of the Greenlandic name Nanoĸ. In Spanish, Nano is a diminutive of several names, especially of Fernando.
What are the properties of silica nanoparticles?
Nano-silica particles are divided into P-type and S-type according to their structure. The P-type particles are characterized by numerous nanopores, which have a pore rate of 0.61 ml/g and exhibit a higher ultraviolet reflectivity compared to the S-type; the latter also has a comparatively smaller surface area.
How does nano-silica affect the durability of concrete?
In this study, the effect of incorporating colloidal nano-silica in concrete prepared with single (OPC) and binary (OPC + Class F fly ash) binders is investigated. The influence of the nano-silica dosage on the mechanical and durability properties of concrete was evaluated in the light of micro-structural and thermal analyses.
What’s the difference between microsilica and nanosilica cement?
Considering that the main difference between nanosilica and microsilica is their respective particle sizes and assuming that the pozzolanic behaviors in both materials are similar, nanosilica will react faster with the cement than microsilica due to its higher SSA (specific surface area).
What are the properties of nanosilica in glass?
The coating of glass with nanosilica results in antireflective properties, contributing to energy conservation (Troitskii et al., 2010 ).