Silica Fume Research Paper

SILICA FUMES
Definition
Silica fume, better known as microsilica,is a non-crystalline polymorph of silica(silicon dioxide). Silica fume is an ultrafine powder that is collected as a by-product elemental silicon and alloys of silicon .Further it consists of spherical particles whose average diameter remains 150nm.It is often confused with fumed silica but its production process, particle characteristics and fields of application are all different from those of fumed silica.
Meaning
Silica Fume Production

Physical Characteristics
Specific Gravity :- 2.2
Specific surface area :- 20,000Sq.meters /Kg
Particle size :- < 1 micron with Avg. Dia of 0.1 micron
Particle Spherical in shape. Amorphous in nature. SILICA FUME COLORS:
1)White
2)Grey

silica fume concreteis used to produce high strength concrete.The factors that have a beneficial effect onstrength( like dense concrete, strongaggregates) also have a beneficial effecton abrasion resistance. silica fumeconcrete caters to all this needs. Chemical resistance A major reason for the improvedresistance of concrete to acidic andsulphate waters is the reduction in theca(oh)2 content of the cement paste,which decreases linearly with the amountof silica fume added. with 20% silica fumeby weight of cement ,very little of ca(oh)2produced by the Portland cementhydration is left in well hydrated cementpaste. Alkali aggregate reaction
The amount of pozzolona needed for reducing the alkali aggregate expansiondepends on the reactivity of pozzolona.studies have shown that less than 10% of silica fume is found adequate for thispurpose as compared to fly ash whichrequires 30%-40% replacement
High Strength Concrete High Performance Concrete (HPC)enhanced with silica fume is so strong itbecomes an economical alternative tosteel. Besides providing architects andengineers with greater design flexibility,there is more usable space, since smaller columns and beams can be used in highrise buildings and long span structuraldesigns.
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