Microsilica Silica Fume

Product Description

Silica fume, also known asmicro silica is silicon dioxide,silica. It is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy productionThe main field of application is aspozzolanicmaterial for high performance concrete.

Technical Specifications:

Application

Because of its extreme fineness and highsilicacontent, silica fume is a very effectivepozzolanicmaterial. Standard specifications for silica fume used in cementitious mixtures are ASTM C1240,[8]EN 13263.[9]

Silica fume is added tocementconcreteto improve its properties, in particular itscompressive strength,bond strength, andabrasionresistance. These improvements stem from both the mechanical improvements resulting from addition of a very fine powder to the cement paste mix as well as from thepozzolanic reactionsbetween the silica fume and freecalcium hydroxidein the paste.

Addition of silica fume also reduces thepermeabilityof concrete tochlorideions, which protects thereinforcing steelof concrete fromcorrosion, especially in chloride-rich environments such as coastal regions and those ofhumid continentalroadways and runways (because of the use ofdeicingsalts) andsaltwater bridges.

Effects of silica fume on different properties of fresh and hardened concrete include

a) Workability: With the addition of silica fume, theslumploss with time is directly proportional to increase in the silica fume content due to the introduction of large surface area in the concrete mix by its addition. Although the slump decreases, the mix remains highly cohesive.

b)Segregation and bleeding: Silica fume reduces bleeding significantly because the free water is consumed in wetting of the large surface area of the silica fume and hence the free water left in the mix for bleeding also decreases. Silica fume also blocks the pores in the fresh concrete so water within the concrete is not allowed to come to the surface.

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