The roles of nano-silica (NS) in nano-modified cement concrete.
Dear Sir,
pl refer these articles which are useful for your research work.
Article Use of nano-silica in cement based materials—A review
https://www.hindawi.com/journals/amse/2016/8453567/
https://pdfs.semanticscholar.org/3b32/fce35e4c33f0ae2e15f367d64a60e9a0947a.pdf
http://onlinepubs.trb.org/onlinepubs/circulars/ec170.pdf
http://www.scielo.br/pdf/mr/v17n3/aop_matres_210013.pdf
Article Effect of nano materials in geopolymer concrete
1. Nano silica reduces the air voids which further improved the density of the concrete and presence of CaO in silica led to formation of extra CSH.
Very useful and interesting discussion, thanks to all.
Nano-particles exhibit unique properties that develop a stronger, more durable concrete with favorable characteristics when added to concrete. Addition of NMs at the time of production of concrete can lead to significant improvements in the strength and life performance of concrete. One of the active areas of research dealing with cement and concrete is strength and durability of concrete containing NPs. Nano-particles can be summarized as follows: i) NPs act as fillers in the empty spaces, ii) well distributed NPs act as crystallization centers (nuclei) of hydration products, increasing hydration rate, iii) NPs assist towards the formation of small sized Ca(OH)2 crystals and homogeneous clusters of CSH composition, and iv) NPs improve the structure of the transition zone between aggregates and paste.
The role of NPs can be summarized as follows: i) NPs act as fillers in the empty spaces, ii) well distributed NPs act as crystallization centers (nuclei) of hydration products, increasing hydration rate, iii) NPs assist towards the formation of small sized Ca(OH)2 crystals and homogeneous clusters of CSH composition, and iv) NPs improve the structure of the transition zone between aggregates and paste.
In recent years, there is a great interest in replacing a long time used materials in concrete structure by nanomaterials (NMs) to produce a concrete with novel functions. NMs are used either to replace a part of cement, producing ecological profile concrete or as admixtures in cement pastes. The great reactivity of NMs is attributed to their high purities and specific surface areas. A number of NMs been explored and among of them nanosilica (NS) has been used most extensively. The role of NPs are: 1) NPs act as fillers in the empty spaces, 2) well distributed NPs act as crystallization centers (nuclei) of hydration products, increasing hydration rate, 3) NPs assist towards the formation of small sized Ca(OH)2 crystals and homogeneous clusters of CSH composition, and iv) NPs improve the structure of the transition zone between aggregates and cement paste.
The addition of NS in cement paste and in concrete can lead to completely different effects. One is size effect, i.e. primarily based on their particle nature, which makes it useful as filling material and the second is the commerce pozzolanic activity of the cluster compounds. NS in cement mortar not only increases the compressive strength, but also results in a finer pore structure, and then reduces overall permeability of hardened cement concrete.
Addition of NMs at the time of production of concrete can lead to significant improvements in the strength and life performance of concrete.
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