Silica Fume for Concrete Products
Silica Fume Concrete is widely used in concrete and fiber cement industries. In addition to its pozzolanic properties its is also a very good filler due to its particle size. These combined properties lead to an extended life expectancy in corrosive environments (resistance to chlorides, acids and sulphates) and improved strength.
High performance concrete containing silica fume is one of the more important advanced materials necessary in the effort to rebuild our nation's infrastructure. Silica fume delivers increased toughness and resistance to abrasion and corrosion, improving sustainability and life-cycle cost efficiency.
Some examples of Silica fume concrete include use for highway bridges, parking decks, marine structures and bridge deck overlays and other applications that are typically subject to deterioration caused by corrosion, abrasion and chemical degradation. Silica fume improves concrete protection against deicing salts, seawater, traffic and heavy impact and other destructive environments.
Silica Fume Concrete Properties
Silica Fume Concrete reacts with lime during cement hydration to form additional calcium silicate hydrates
(C-S-H gel) which bonds the components together creating a dense matrix.
Silica Fume Concrete is 100 to 150 times smaller than a cement particle and can fill the interstitial voids. The packing effect reduces strongly the concretes porosity and permeability.
Silica Fume Concrete improves component packing and adhesion, which has a direct impact on the mechanical properties, especially on strength.
Porosity/ Permeability/ Resistance to Corrosion
Addition of Silica Fume Concrete reduces porosity by decreasing pore size. Porosity and permeability reductions inhibit the penetration of aggressive agents. The use of Silica Fume Concrete is beneficial
to prevent concrete from corrosion in difficult environments: harbors, airports, chemical areas, and coastal buildings are common examples.
Silica Fume Concrete protects the concrete against the alkali reaction. Its fine and amorphous
particles react with cement alkalies and reduce their content in the concrete before hardening.
By reducing concrete permeability, Silica Fume Concrete reduces water movements and internal pressures leading to irreversible degradation.